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JOURNAL
OF THE
ASSOCIATION OF OFFICIAL
AGRICULTURAL CHEMISTS
BOARD OF EDITORS
R. W. Barco, Chairman
R. E. DoouitTLe WiiiiaM FREAR!
C. B. Lipman R. B. DEEMER
Marian E. Lapp, Associate Editor
1Died January 7, 1922
VOLUME V
1921-1922
1922
ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
BOX 290, PENNSYLVANIA AVENUE STATION
WASHINGTON, D. C.
S
583
47
Ae
Copyricut, 1922,
BY
Tue ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
-CONTENTS
PROCEEDINGS OF THE THIRTY-SIXTH ANNUAL CONVENTION,
NOVEMBER, 1920.
PAGE
Officers, Committees, Referees, and Associate Referees of the Association of Official
Agricultural Chemists, for the year ending November, 1921................
Members:and Visitors: Present, 1920 Meeting:.........0.. 50.20.00 sbuec coe eke 8
President's Address*” (By? H-;G@. Lythgoe® 2 iho nk. ee ee ne eee es shor 14
MonbDay—MorNInG SESSION.
REporejongwaterai By) |. Ws SALON. o-pceter ys) apentgee Rie dato tde ox sabiseys/oh<fayayspaiee eyci clea 29
Report on Tanning Materials and Leather. By F. P. Veitch................... 32
Report on Insecticides and Fungicides. By J. J. T. Graham................... 33
Pickering Bordeauxjsprays: . By Fi. Gj Cooke: 5 s-yofhi e085 ar oyoisya isis oie sp4yeletoiaisis 1s ye an 50
Reportion:Soils.\ By We Ha Maciintire’ (a <(4. 2.6 x05, 1s:¥ous) > 3p jorejoyse\a 4 ope «eye 0 (0,008 6 52
Report on Testing Chemical Reagents. By W. D. Collins..................... 54
Reporsjon! EnudewWiber;, By .G.1. Bidwell... o-<.<ytovenie/b «8 aictstere $9e.s/<siallaya/ste aaa suese
A Study of the Details of the Crude Fiber Method. By G. L. Bidwell and L. E. 3
2) D1 6s G Cn RESET OE EO Me OBO OE ome tine ait ery ao cle Gnd Com ces ee oe 8
The Detection of Ground Bran in Shorts. By J. B. Reed...................... 70
The Detection of the Adulteration of Shorts. By D. B. Bisbee................. 74
Report on Stock Feed Adulteration. By B. H. Silberberg..................... 77
Reportion saccharine, Products... By. FH. S. Paine oo. vee Majo co ciiscee.s s cicies ee cig sie se 78
MonpDay—AFTERNOON SESSION.
Report.on Fertilizers. “By Re N= Brackett. 2c cee sini woe sie ails ited oles Sabai 80
Report on the Determination of Borax in Fertilizers and Fertilizer Materials. By
yi tcaay Ede sR OS est rs cteverey Scticn dt hte el ach she het Ualt Gat spenet.o'c! Shatain’ ele telie|siel «1 aT esi haa eT
Report on Borax in Mixed Fertilizers. By R. B. Deemer...................... 86
The Distillation Method for the Estimation of Borax in Mixed Fertilizers. By J.
il loeind Giga eee yoe ¢ Doobica ves DOGO oO Op bce teens Ot Moe ere nr rane 88
The Composition and Preparation of a Neutral Solution of Ammonium Citrate. By
RROPITISOM Se eT vate ochre etae, TACT lath be, ANE AEFI MEWS Io fe wie Melaleky at's orale See slots 92
Report on Available Phosphoric Acid in Precipitated Phosphates. By H. D.
RAASKITIS Ney a terat reeds cet Mle PSs Petts gine Selo te Da htatere kas WEED ohalerats 97
A Modified Method for the Determination of Phosphoric Acid. By A. W. Clark
chee Ue, Co) Co a a SSeS ORIOL IRIGISES Gita: id ean Ie ae eee eee 103
Report OnUNitrogeny Dy pla Kev REI pSiie/s Ssteisiaie eietayo/a ole stile. o:a area salve wehbe der fev 104
Boric Acid for Neutralizing Ammonia in Nitrogen Determinations. By H. D.
2 he BOR ORIASADD AOL aee Abt OSC Ans her ACHOCDORODO BEBO eon Open 10
The Kjeldahl Nitrogen Method and Its Modifications. By A. E. Paul and E. H. ;
GOR able bya eiChae OCo EOE COE COS EEE OOD A ORIED bo char asta y 405 Sarees S 10.
Report.on Potash Availability. By ALG McCalliiciis ice aes stan aes ctertite > deroere 132
Pot Culture Tests on the Availability of Potassium from Greensand Composts. By
LNA aSreir il ep eatpre HO deo Dor OOS Ode. a ASO Dan aE ane Hee Eamonn 133
Report on Inorganic Plant Constituents. By J. H. Mitchell................... 136
Report on Sulfur and Phosphorus in the Seeds of Plants. By W. L. Latshaw. 136
Reponaonmomigss sisvaGraW PLOGVEIs or ar aciapisies <2 oococ stare cise te ioe cle 141
Repogmonrnixalatds ub ye Anu NEussni| tease ea ne oieys vesemieveitic.o) che akon a iaustsvels ovayern 149
Report on Arsenicals. By W. O. Emery SAGER OR BRT ee RS ties ey Oe Oem 149
Reporte onjoyatberic Drugs ByiG. Oe Wrights, crscc.cls cv sjs.ciject cite ac cede altar 150
Report on Methods of Analysis of Morphine, Codeine, and Diacetylmorphine
AUTeK One) Emig Omen GLYyCantnny. wy. Merrie tary gece Co na ee 150
Report on Medicinal Plants. By Arno Viehoever................20ee00eereees 155
Method for the Examination of Procaine (Novocaine). By Alfred W. Hanson.... 163
Study of the Distillation Method for the Estimation of Santalol in Santal Oil.
By, © Wi ElArrisOn ser terme be eal a crcke riches ters seco hee a Se ee aR oN 166
iv CONTENTS
TuESDAY—MorNING SESSION. PAGE
The 'Eryoscopy.of Milk, | By Julaus Hortyvetin tier svsceiete = [-\ -etexcleieseleteyeds alsiar el ebelstns 172
Determination of Fat in Malted Milk. By J. T. Keister...................... 176
Report) on Fats/and!@ils: By; Ro Haakeerrap tg ae iets = yer seis eyeeteis =ie ee Uiaveee 178
Report/on' BakingPowder. By (Gilly Maingie oe r c iste a> eraienieeieaee nes ae ee 179
Determination of Total Carbon Dioxide in Baking Powder. By C.S. Robinson.. 182
Report on Eggs and Egg Products. By H. L. Lourie........................-- 191
Report on Coloring Matters in Foods. By W.E. Mathewson.................. 196
Reportion Metalsiiniboods:, By We tei Clarkern a mrcitacte ciemiilcie eielaleian ser 219
Report on Pectin in Fruits and Fruit Products. By D. B. Bisbee............... 224
Report oni Canned, Foods: By W., DuiBigelowe,«jccf< d.cjei> cseucyonneicid © sanjatepeyenanepeys egeys 225
Effect of the Use of Different Instruments in Making a Microscopic Examination
for Mold in) Tomato Products, “By Bayjmibloward. saeiace- eel meme anak 226
Honorary President’s Address. By H. W. Wiley................-.0ceeseseeee 229
Address of the Secretary of Agriculture. By E. T. Meredith................... 238
TUESDAYW—AFTERNOON SESSION.
Report’onCereal ‘Foods. By\G: Hs Bailey-'-- 1s.) tosis tetty< ne ieee «lt ieialt. tahele 241
A Note on the Polarization of Vinegars. By R. W. Balcom and E. Yanovsky.... 245
Salad Dressings and Their Analysis. By H. A. Lepper................0....... 248
Report on the Determination of Shells in Cacao Products. By W.C. Taber...... 253
Cacao Products with Special Reference to Shell Content. By B. H. Silberberg.... 260
Report on Methods for the Examination of Cacao Butter. By W.F. Baughman.. 263
Report oni|Coffees }, By He 7As Lepper sry wilt) ost piso eletace, a eevee ee eat. Reet 267
Robusta Coffee. By Arno Viehoever and H. A. Lepper.................00..0. 274
Report‘onPea- / “By ESM: ‘Batley’: cs.cccthoc ths sore tacos atels fos aretatetarstaretarats loyavelte ea eeaeene 288
WEDNESDAY— MORNING SESSION.
Report of Committee on Editing Methods of Analysis. By R. E. Doolittle...... 297
Report of Committee on Quartz Plates Standardization and Normal Weight. By
Brederick Bates 0% 1c.aye ot aie tency iva ciao Teer aerate Oak ee eee 315
Report of Committee on Methods of Sampling Fertilizers to Cooperate With A
Similar Committee of the American Chemical Society. By C. H. Jones.... 315
Report of Committee on the Revision of Methods of Soil Analysis. By C. B.
IY oyro he ees 3 ie eit TC ene CR EAS Ren ere rnPra PL mbes SNM CENT 3 ANY oc 316
Report of Committee on Vegetation Tests on the Availability of Phosphoric Acid
in Basic 'Slags 4 By Had aHaskinsyy. $7, crtespaty acts male ee deste ut An ase eete 317
WEDNESDAY—AFTERNOON SESSION.
Report of the Secretary-Treasurer for the Year Ending November 17, 1920. By
GaLfAlsberg.cqraieod oh, bee. ee ics compet htc R tow. oie, ee 318
Financial Report on the Journal and Book of Methods. By C. L. Alsberg...... 320
Report of the Board! of Editors: (By: €: Is Alsberge. 22): 5 ah) ek Dawtiodieailen 322
Report of Committee on Recommendations of Referees. By B. B. Ross......... 326
Report of Subcommittee A on Recommendations of Referees. By B. B. Ross... 327
Report of Subcommittee B on Recommendations of Referees. By H.C. Lythgoe.. 333
Report of Subcommittee C on Recommendations of Referees. By R. E. Doolittle.. 339
Report of Committee to Cooperate With Other Committees on Food Definitions.
Bay: Walliami ire ar ccs typ aeusceccrebcteeusysaeesvcieteascercuewoksisacdedepetens trove ei siete hee eee 349
Report of Committee on Resolutions. By William Frear...................... 349
PROCEEDINGS OF THE THIRTY-SEVENTH ANNUAL CONVENTION,
OCTOBER, 1921.
Officers, Committees, Referees, and Associate Referees of the Association of Official
Agricultural Chemists, for the Year Ending October, 1922.................. 352
Members and Visitors Present, 1921 Meeting....................cceceeeeeeees 359
President's Address? By Who Hands oo aie) hase tecuatseisieve teicaa eee 366
MonpAy—MorNING SESSION.
Report on Water: ‘By: J’. W.:Sales 2 osc. cicten=a-< «s.cse.4i 0-2 01s 6 are ae ea 79
Report on Tanning Materials and Leather. By F. P. Veitch................... 388
Report on Insecticides and Fungicides. By J. J. T. Graham................... 392
CONTENTS v
PAGE
Reportion Solss bya EuvMachntires aoe eee eee bee wee 405
Reportomonifur: | By) Wallin Mackntine 220 =) ON eh LRU ee Pe Ue ne 0a 418
Report on Foods and Feeding Stuffs. By J. B. Reed_.__---------------------- 418
Report.on\Grude! Fibers ByiG. Es-Bidwelles2 22-2 6222-22 ise ee NE 421
A Study of the Gephart Method for the Determination of Crude Fiber. By L.
EvBopstyand! Gyles Bidwelhs sea tare we We ie es a EARS 422
Report on Stock Feed Adulteration. By H. E. Gensler___---_..-.------------- 424
MonbDaY—AFTERNOON SESSION.
Reportion-Saccharine: Products:) By H.'S).Painez)2 22405 bua ye ee 429
Detection of Artificial Invert Sugar in Honey. By S. F. Sherwood____--________ 429
Reportion) MaplevProducts:, ByiG@.Hijoness=) 2-222 52=- ses. 8 436
Report.on Maltose: Products: By |O.'S./Keeners 222 0-2-2222 2 202-22 So ae 436
Report on Sugar-house Products. By J. F. Brewster. -...--------------------- 437
PATINIOUMCEIER ES ans ern un aes eee os Se ee see es oe ae i
Obituary on Dr. William Frear. By R. N. Brackett._--........-.-..-..=Viw_ iti
ReportonBertilizers:), By) R>/N> Brackett 220220 of eo 439
Report on the Determination of Boric Acid in Fertilizers and Fertilizer Materials.
Byala aR Ross seca oe COA en a ee ee Se 440
Report on the Preparation of a Neutral Solution of Ammonium Citrate. By C.S.
RObInsOn eae ar weet ER ae ee ys eee aed Su ee de ey 443
Some Experiences with the Alkaline Permanganate Method. By C. S. Robinson
ATCA OES SRVVALILERS He epee ets ae NCOs cy centage eel SL eM awake Week eee 446
Reportion| Nitrogen, 1 Byala bhelps=22: 222 | ea ee ee 450
Availability of Nitrogen by the Alkaline Permanganate Method. By E. W. Ma-
RLU CL epsilon eae as 2 MM RENEE ay oie a a 454
Reportiony Potash. By. eer Oye nae ec 456
Determination of Small Amounts of Potash by the Lindo-Gladding Method. By
WVilliamublaze nip eres sees te ee ee ee ee Pos ee ee 456
Report on Precipitated Phosphates. By H. D. Haskins______________________- 460
Determination of Extremely Small Amounts of Phosphorus by the Official Method.
Bs yglen@ap Wille yee emer nS aN ie ok Se SS es Su De ie ae 465
Report on Inorganic Plant Constituents. By A. J. Patten_____________________ 467
Report on Sulfur and Phosphorus in the Seeds of Plants. By W.L. Latshaw____ 468
Cryoscopic Examination of Milk. By Julius Hortvet________._.-____________- 470
CrvoscopyjonMulk:)/ Byib wii Baileys ==. oye sea be OSI Ee 484
Report on the Determination of Moisture in Cheese. By L. C. Mitchell_________ 498
Determination of Fat in Malted Milk. By J. T. Keister_____.___.___________- 507
Moisture/@ontent of Mredi Milk) By G. EoHolme)- 22262 ts 509
Reportonivats and Oils aby Ga Sujamiesonln el eo ee eee ek oe ee tees 512
Modified Procedure for the Determination of the ‘“‘Turbidity Point” of Butter Fat.
By APATITE Se GEN Deb pss = ens es oem iy ee a bere se a 5 ae OS Dd 512
Report. oniBaking, Powder) Byjbe iH. Bailey 2020) etn ae 514
Report on Fluorides in Baking Powder. By J. K. Morton____________________- 522
RepostonsD rigs iby) Ge iW OOVeNs ame ana iney 2 2h Pe Vee en Se $25
Qualitative and Quantitative Analysis of Arsphenamine (Salvarsan) and Neoars-
phenamine (Neosalvarsan). By G. W. Hoover and C. K. Glycart__________ 525
Report on the Determination of Alcohol in Drug Products. By A. G. Murray___ 530
Report on the Determination of Chloroform in Drug Products. By A.G. Murray__ 539
Report on the Determination of Chloral Hydrate in Drug Products. By A. G.
Mn ray eee ee ee ae a eh AE nae ee Set 541
Investigation of Analytical Methods for the Analysis of Silver Proteinate. By
NEU LE IG Wy el Ys UU ACARI SI ae ile a eR a tog 542
Report on the Determination of Camphor in Pills and Tablets, by the Alcohol
Distillation Method: | By.G. JH. Arnersase Ube oo te Be 544
Estimation of Santalol in Santal Oil by the Assay Method of the United States
Pharmacopeeia and by the Distillation Method. By C. W. Harrison_______- 545
Reportoniuunpentine-.) By jn On Clarkes leew 2 547
Volume Weight Determinations of Crude Drugs and Spices. By A. Viehoever___ 553
Microsublimation of Plant Products. By A. Viehoever_______-__________-____- $57
Identification of Crude Drug Substitutes. By A. Viehoever_______.___________- 560
Report onsAlkalords mb yp Neve LiSS, ftom i ee Ue LN UU ARE a 564
Report on Methods of Analysis of Morphine, Codeine and Heroine (Diacetyl-
MOLINE) EB VAC Men Gly Canta eee See uent se ery yee matt Ve 1573
Report on Laxative and Bitter Tonic Drugs. By H.C. Fuller__........._..... 575
VI CONTENTS
PAGE
Report on) Acetylsalicylic Acid) | By AyE. Paulbzess. cee es eo ee 581
Report on Methods for the Determination of Monobromated Camphor in Tablets.
ByiC.D) Wright... 2. 2 Sk ok 2 Oe ees epee see So ete 2 587
Report on Methods for the Examination of Procaine (Novocaine). By A. W.
Hanson... - cost sa se cee ao a ee a ee a ae a ee Ea 589
Preliminary Report on Methods for the Separation and Estimation of the Principal
CinchonayAlkaloidsia is valve © seat 0 ree eee eee ee 594
The Differentiation of Japanese and American Peppermint Oils. By E.O. Eaton__ 597
WILLIAM FREAR, 1860—1922
EE
WILLIAM FREAR
William Frear was born in Reading, Pennsylvania, March 24, 1860, and
passed away at his home at State College, Pennsylvania, January 7, 1922.
The end came suddenly following a stroke of apoplexy. His wife, four
children and a host of friends mourn his loss.
He was of Huguenot ancestry, the first member of the family, Hugo
Frear, having settled in New Paltz, New York, in 1677. William Frear
was the son of the Rev. George and Malvina (Rowland) Frear. His
father was a Baptist minister at Reading and Norristown, where he at-
tended the public schools. Later they moved to Lewisburg, Pennsylvania,
where William Frear entered Bucknell University with the purpose of
fitting himself to be a civil engineer. He, however, developed a taste for
chemistry and the natural sciences and after graduation accepted a
position as assistant in natural science at Bucknell University.
He received his Bachelor of Arts degree from Bucknell University in
1881. Later he pursued postgraduate work at Harvard University and
at the Illinois Wesleyan University, and from the latter institution
received, in 1883, the degree of Doctor of Philosophy. His work both in
the public schools and in the universities was characterized by excellency
of scholarship.
Dr. Frear began his life work, after graduation, as assistant chemist in
the Bureau of Chemistry, U. S. Department of Agriculture, under Dr.
H. W. Wiley, the newly appointed chief chemist, a position which he held
until 1885, when he was appointed assistant professor of agricultural
chemistry at the Pennsylvania State College. He, however, always kept
in close touch with the U. S. Department of Agriculture, serving as special
agent of the Department from 1900 until his death and as chairman of the
Food Standards Committee. A year after his appointment at State
College he was advanced to the rank of professor and served as professor
of experimental agricultural chemistry and head of the department from
1908 until the time of his death. He was also vice-director of the Agri-
cultural Experiment Station from 1887, two years after its organization,
until the time of his death.
The esteem in which he was held for his scholarship, scientific attain-
ments, broad vision, his ability to weigh and solve difficult problems, and
his capacity for work, caused his services to be requisitioned not only in
the college, but in the community, state and nation. For example, he
was chemist of the State Board of Agriculture from 1888 until the Board
was abolished in 1919; chemist in charge of analysis of fertilizers under
the State Fertilizer Control from 1888 until 1919; chemist of the Penn-
sylvania State Department of Agriculture from 1895; chemist of the State
Dairy and Food Commission from 1895; chemist*of the State Cattle Food
Control from 1902 until 1905; editor of Agricultural Science from 1892 to
1894; secretary of the Society for the Promotion of Agricultural Science
from 1893 to 1895, and president of that organization in 1903.
While best known for his interest and work in connection with pure
foods, food definitions, food standards and legislation, Dr. Frear was
regarded as an authority on a wide range of subjects, such as soils, ferti-
lizers, lime, feeds, tobacco culture and meteorology. The scope of his
investigations is indicated by the number of papers on a great variety of
subjects of which he was author or joint-author, amounting to a hundred
or more bulletins and special manuscripts published by the Experiment
Station and in scientific journals. The papers show careful scientific
work and are expressed in language in keeping with his excellent and
thorough literary training. In addition to his investigational work, he
taught agricultural chemistry and various other lines of agriculture at
State College for many years. One who knew him best says: “It was a
great privilege to ke a member of his classes. He was unusually careful
in the presentation of material and most skilful in helping his students to
analyze and grasp the problems involved”’.
On account of his wide range of information, so essential in legislation
of this kind, and because of his clear thinking and exceptionally good
judgment, he wes often called into consultation when laws were being
framed relating to foods, fertilizers, lime and other subjects of importance
in agriculture. For the same reasons, his counsel was in demand in com-
munity matters, such as schools, churches, water system, street improve-
ment, and indeed in every movement of importance to the welfare of the
community, in which he always took an active interest.
He wes an honored member of scientific societies, such as the American
Chemical Society, the Academy of Political and Social Science, the Wash-
ington Academy of Sciences and the Association of Official Agricultural
Chemists; and a highly esteemed member of several Greek letter fra-
ternities. He was also a member of the Cosmos Club of Washington,
and of Bellefonte Lodge No. 268, Free and Accepted Masons, of which he
was master in 1907. He was also post commander of Constans Com-
mandery of Knights Templar.
Such was Dr. Frear, scientist and scholar. His long, faithful and
efficient service at State College, in his community, state and nation, and
his conspicuous ability as a teacher, investigator, administrator, author
and lecturer, challenge our highest admiration. But what of Frear the
man? “A gentleman; a Christian gentleman. His personality was most
admirable”, so says Dr. Wiley, who has perhaps known him longest.
“With all our admiration of Dr. Frear as an eminent scientist, we admire
another side of the man stil! more; his splendid Christian character and
fine human qualities that left an indelible impression upon the lives of all
those who knew him, and upon thousands of people who counted him as
their friend. He possessed to a remarkable degree the admirable quali-
ties of kindness, cheerfulness, patience, charity and thoughtfulness. No
one was ever associated with him in any capacity who was not helped in
some way’, is the testimony of one who was thrown in daily contact with
Frear the man. This estimate of Frear the man is in perfect agreement
w |
with the impression gained by the writer of this sketch during ten years’
association with him in the activities of the Association of Official Agri-
cultural Chemists. His conspicuous ability and admirable personality
made him an outstanding figure at every meeting of the association.
It seems fitting in closing this tribute to the life and work of Dr. Frear
to make special mention of his long, faithful and efficient service as a
member of this association. According to the records, Dr. Frear first
became identified with the Association of Official Agricu!tural Chemists
at its fourth meeting, 1887. At the sixth meeting, 1889, he was made a
member of the Executive Committee. At the eighth meeting, 1891, he
made a very valuable report, “Abstracts of Various Methods of Determi-
ning Nitrogen”, which no doubt led to the appointment, at the ninth
meeting, 1892, ofa Committee on Abstracts of Methods of Analysis, of
which he was made chairman, and served as such for several years. He
was vice-president at the thirteenth meeting, 1896, and president the
following year, 1897. The following statement from his presidential
address is worthy of quotation: “Primarily, the work of the association
has been chiefly along the lines of importance to the official chemist.
This must still be, to a large extent, true of the association’s work. But
it will fail of its opportunities and choose an ideal lower than it may proper-
ly select if its work be not pushed also, in large measure, along more dis-
tinctly scientific lines”. In this address also he cited, in connection with
his work on food adulteration, statistics showing the value of the food
products of the country, amount of consumption and related subjects,
and called especial attention to two ways in which this association could
help the food control chemist: “(1) By a careful selection, accurate descrip-
tion, and test of methods fitted for the control examination of the various
classes of adulterated food materials upon the market; (2) by taking steps
to secure the establishment of standards of composition for pure food
substances, just as druggists have done for drugs. * * * A similar
work must be done for foods.”
It is noteworthy that at this meeting a Committee on Food Standards
was appointed, consisting of Messrs. Wiley, Weber, Scoville, Jenkins and
Frear. Dr. Frear served as chairman of this committee during its entire
existence. He made practically all of its reports. In 1901, on the reso-
lution of Dr. Frear, this committee cooperated with the National State
Dairy and Food Commissioners. Writing of his work in connection with
these committees Dr. Wiley, who is of all men best qualified to speak,
says: ‘‘He did the bulk of the clerical work and took care of the correspond-
ence incident to the great work of establishing standards. I think his
work was in that line, and I believe he remained chairman of the Stand-
ards Committee up until the time of his death. The actual volume of
printed matter containing the standards adopted is small, but the data
which were collected, the literature which was read, and the hearings
which were held, if they could all be published would be most volumi-
nous. It was Dr. Frear’s duty and privilege to sift and sort, to condense
LB
and prepare for action this large mass of material. He did this with care
and industry and a success which are not at all recognized by the public
at large. * * * He never became angry. He never rubbed a wit-
ness the wrong way. He was a discreet, cool and efficient presiding officer,
and whatever the credit there be to be paid to the standards adopted, he
should receive the greater part’’.
This committee functioned under Congressional authority until the
passage of the Federal Food and Drugs Act in 1906. Later, in 1913, a
new committee, the so-called Joint Committee of Definitions and Stand-
ards of the U. S. Department of Agriculture, was founded. Dr. Frear
was again called upon for service. He was chairman of this committee
at the time of his death.
Dr. Frear rarely if ever missed a meeting of the association from the
time he became identified with it in 1887, until the time of his death. He
always took a vital interest in all its activities and contributed freely
and wholeheartedly of his time and talents in making them a success.
He was an honored member of this association, having served on its Execu-
tive Committee, as vice-president, as president, as a member of numerous
committees, and as a member of the Board of Editors of This Journal
from 1920 until his death.
In the passing of Dr. William Frear the association has lost a most
capable worker and a wise counsellor, and many of its members, a warm
personal friend. In life it could well be said of him:
“Whom God illumines,
Dwells in undimmed day;
*Mid storm and night,
He treads a clear, sure way’.
When the summons came he met death, of which he had no fear, “like
one who wraps the drapery of his couch about him and lies down to pleas-
ant dreams”’.
R. N. Brackett.
= a
ry
~*~
.
‘
= -
PROCEEDINGS OF THE THIRTY-SIXTH ANNUAL
CONVENTION OF THE ASSOCIATION OF
OFFICIAL AGRICULTURAL
CHEMISTS, 1920.
OFFICERS, COMMITTEES, REFEREES, AND ASSOCIATE
REFEREES OF THE ASSOCIATION OF OFFICIAL
AGRICULTURAL CHEMISTS, FOR THE YEAR
ENDING OCTOBER, 1921.
Honorary President.
H. W. Witey, Woodward Building, Washington, D. C.
President.
W. F. Hann, Agricultural College, Agricultural College, Miss.
Vice-President.
F. P. Verrcs, Bureau of Chemistry, Washington, D. C.
Secretary-Treasurer.
R. W. Batcom, Box 290, Pennsylvania Avenue Station, Washington, D. C.
Additional Members of the Executive Committee.
A. J. Parren, Agricultural Experiment Station, E. Lansing, Mich.
H. D. Haskins, Agricultural Experiment Station, Amherst, Mass.
PERMANENT COMMITTEES.
Cooperation with Other Committees on Food Definitions.
William Frear (State College, Pa.), Chairman.
Julius Hortvet, St. Paul, Minn.
C. D. Howard, Concord, N. H.
Recommendations of Referees.
(Figures in parenthesis refer to year in which appointment expires.)
R. E. Dootrrrte (Transportation Building, Chicago, Ill.), Chairman.
1
2 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
SuspcommitTeEE A: B. B. Ross (1926), (Polytechnic Institute, Auburn, Ala.), Chairman,
W. H. MaclIntire (1924), C. C. McDonnell (1922). [Fertilizers (borax in fertil-
izers, preparation of ammonium citrate, nitrogen, potash, potash availability,
precipitated phosphates), inorganic plant constituents, (sulfur and phosphorus
in the seeds of plants, calcium and magnesium in the ash of seed), water, tanning
materials and leather, insecticides and fungicides, and: soils (sulfur in soils).]
SuscommiTtee B: H. C. Lythgoe (1926), (State Department of Public Health, Boston»
Mass.), Chairman, E. M. Bailey (1924), C. A. Browne (1922). [Foods and feed-
ing stuffs (crude fiber, stock feed adulteration), saccharine products (honey, maple
products, maltose products, sugar-house products), dairy products (moisture in
cheese, cryoscopic examination of milk, methods for fat in malted milk and dried
milk), fats and oils, baking powder (fluorides in baking powder), drugs (exami-
nation of arsphenamine and neoarsphenamine; determination of alcohol in drug
preparations; determination of chloroform in drug preparations; determination of
chloral hydrate in drug preparations; analytical methods for the determination of
silver in silver proteinates; determination of camphor in pills and tablets by the
alcohol distillation method; distillation method for the estimation of santalol in santal
oil; turpentine; crude drugs; alkaloids; methods of analysis of morphine, codeine
and diacetylmorphine; laxative and bitter tonic drugs; the determination of calo-
mel, mercuric chloride and mercuric iodide in tablets; the analysis of acetylsalicylic
acid; methods for the examination of phenolphthalein; method for the analysis
of monobromated camphor; methods for the examination of procaine; preliminary
report upon methods for the separation and estimation of the principal cinchona
alkaloids; differentiation of Japanese and American peppermint oils), testing
chemical reagents, non-alcoholic beverages, and eggs and egg products.]
Suscommitree C: R. E. Doolittle (1926), (Transportation Building, Chicago, IIl.),
Chairman, W. C. Geagley (1924), W. W. Randall (1922). [Food preservatives
(saccharin), coloring matters (oil-soluble colors), metals in foods (arsenic), pectin
in fruits and fruit products, moisture in dried fruit, canned foods, cereal foods,
limit of accuracy in the determination of small amounts of alcohol in beers, vine-
gars, flavoring extracts, meat and meat products (separation of meat proteins,
decomposition of meat products, gelatin), spices, determination of shells in cacao
products, methods for the examination of cacao butter, coffee, tea, and nitrogen
in foods.]
Board of Editors.
R. W. Balcom (Box 290, Pennsylvania Avenue Station, Washington, D. C.), Chairman.
E. F. Ladd (1921). R. E. Doolittle (1923).
C. B. Lipman (1922). William Frear (1924).
N. A. Parkinson, Associate Editor.
Ediling Methods of Analysis.
R. E. Doolittle (Transportation Building, Chicago, Ul.), Chairman.
B. B. Ross. J. W. Sale.
A. J. Patten. G. W. Hoover.
W. H. MacIntire.
1921| OFFICERS, COMMITTEES, REFEREES AND ASSOCIATE REFEREES 3
SpecrAL COMMITTEES.
Vegetation Tests on the Availability of Phosphoric Acid in Basic Slag.
H. D. Haskins (Agricultural Experiment Station, Amherst, Mass.), Chairman.
C. B. Williams. B. L. Hartwell.
W. B. Ellett. J. A. Bizzell.
Committee to Cooperate with the American Society for Testing Materials on the Subject of
Agricultural Lime.
W. H. MacIntire (Agricultural Experiment Station, Knoxville, Tenn.), Chairman.
William Frear. F. P. Veitch.
Commiittee on Revision of Methods of Soil Analysis.
C. B. Lipman (Agricultural Experiment Station, Berkeley, Calif.), Chairman.
W. H. MaclIntire. R. Stewart.
A. W. Blair. J. A. Bizzell.
Committee on Quartz-Plate Standardization and Normal Weight.
Frederick Bates (Bureau of Standards, Washington, D. C.), Chairman.
C. A. Browne. F. W. Zerban.
Representative to Cooperate with the Revision Committee of the United States
Pharmacopeia.
L. F. Kebler, Bureau of Chemistry, Washington, D. C.
Representatives on the Board of Governors of the Crop Protection Institute of the National
Research Council.
L. Hartwell, Kingston, R. I.
J. Patterson, College Park, Md.
B.
EL
Referees and Associate Referees.
Fertilizers:
Referee: R. N. Brackett, Clemson Agricultural College, Clemson College, S. C.
Boraz in fertilizers:
Associate referee: W. H. Ross, Bureau of Plant Industry, Washington, D. C.-
Preparation of ammonium citrate: :
Associate referee: C.S. Robinson, Agricultural Experiment Station, E. Lansing,
Mich.
Nitrogen:
Associale referee: 1. K. Phelps, Bureau of Chemistry, Washington, D. C.
Potash:
Associate referee: J. T. Foy, Clemson Agricultural College, Clemson Col-
lege, S. C.
4 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Potash availability:
Associate referee: A. G. McCall, Agricultural Experiment Station, College
Park, Md. }
Precipitated phosphates:
Associate referee: H.D. Haskins, Agricultural Experiment Station, Amherst,
Mass.
Inorganic plant constituents:
Referee: A. J. Patten, Agricultural Experiment Station, E. Lansing, Mich.
Sulfur and phosphorus in the seeds of plants:
Associate referee: W. L. Latshaw, Agricultural Experiment Station, Man-
hattan, Kans.
Calcium and magnesium in the ash of seed:
Associate referee: A.J. Patten, Agricultural Experiment Station, E. Lansing,
Mich.
Water:
Referee: J. W. Sale, Bureau of Chemistry, Washington, D. C.
Tanning materials and leather:
Referee: F. P. Veitch, Bureau of Chemistry, Washington, D. C.
Insecticides and fungicides:
Referee: J. J. T. Graham, Bureau of Chemistry, Washington, D. C.
Soils:
Referee: W.H. MacIntire, Agricultural Experiment Station, Knoxville, Tenn.
Sulfur in soils:
Associate referee: W.H. MacIntire, Agricultural Experiment Station, Knox-
ville, Tenn.
Foods and feeding stuffs:
Referee: J. B. Reed, Bureau of Chemistry, Washington, D. C.
Crude fiber:
Associate referee: G. L. Bidwell, Bureau of Chemistry, Washington, D. C.
Stock feed adulteration:
Associale referee: UH. E. Gensler, State Department of Agriculture, Harris-
burg, Pa.
Saccharine products:
Referee: H. S. Paine, Bureau of Chemistry, Washington, D. C.
Honey:
Associate referee: S. F. Sherwood, Bureau of Plant Industry, Washington,
D. C.
Maple products:
Associate referee: C. H. Jones, Agricultural Experiment Station, Burling-
ton, Vt.
1921| OFFICERS, COMMITTEES, REFEREES AND ASSOCIATE REFEREES 5
Maliose products:
Associate referee: O.S. Keener, Bureau of Chemistry, Washington, D. C.
Sugar-house products: d
Associate referee: J. F. Brewster, Sugar Station, New Orleans, La.
Dairy products:
Referee: Julius Hortvet, State Dairy and Food Commission, St. Paul, Minn.
Moisture in cheese:
Associate referee: 1. C. Mitchell, U. S. Food and Drug Inspection Station
310 Federal Office Building, Minneapolis, Minn.
Cryoscopic examination of milk:
Associate referee: E. M. Bailey, Agricultural Experiment Station, New
Haven, Conn.
Methods for fat in malted milk and dried milk:
Associate referee: J.T. Keister, Bureau of Chemistry, Washington, D. C.
Fats and oils:
Referee: G.S. Jamieson, Bureau of Chemistry, Washington, D. C.
Baking powder:
Referee: L. H. Bailey, Bureau of Chemistry, Washington, D. C.
Fluorides in baking powder:
Associate referee: J. K. Morton, Bureau of Chemistry, Washington, D. C.
Drugs:
Referee: G. W. Hoover, U. S. Food and Drug Inspection Station, Transporta-
tion Building, Chicago, Ill.
Determination of alcohol in drug preparations:
Associate referee: A. G. Murray, Bureau of Chemistry, Washington, D. C.
Determination of chloroform in drug preparations:
Associate referee: A. G. Murray, Bureau of Chemistry, Washington, D. C.
Determination of chloral hydrate in drug preparations:
Associate referee: A. G. Murray, Bureau of Chemistry, Washington, D. C.
Analytical methods for the determination of silver in silver proteinates:
Associate referee: W. L. Mitchell, Room 1012, U. S. Appraiser’s Stores,
New York, N. Y.
Determination of camphor in pills and tablets by the alcohol distillation method:
Associate referee: G. H. Arner, Room 1012, U. S. Appraiser’s Stores, New
York, N. Y.
Distillation method for the estimation of santalol in santal oil:
Associate referee: C. W. Harrison, U. S. Food and Drug Inspection Station,
Park Avenue Building, Baltimore, Md.
Turpentine:
Associate referee: J. O. Clarke, U. S. Food and Drug Inspection Station,
U.S. Custom House, Savannah, Ga.
6 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Crude drugs:
Associale referee: Arno Viehoever, Bureau of Chemistry, Washington, D. C.
Alkaloids:
Associale referee: A. R. Bliss, Emory University, Emory University, Ga.
Methods for analysis of morphine, codeine and diacetylmorphine:
Associate referee: C. K. Glycart, U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, Il.
Larative and bitter tonic drugs:
Associate referee: HH. C. Fuller, Institute of Industrial Research, Washing-
ton, D. C.
Determination of calomel, mercuric chloride and mercuric iodide in tablets:
Associate referee: EE. C. Merrill, United Drug Company, Boston, Mass.
Analysis of acetyl salicylic acid:
Associale referee: A. E. Paul, U. S. Food and Drug Inspection Station,
Government Building, Cincinnati, Ohio.
Methods for the ecamination of phenolphthalein:
Associate referee: Samuel Palkin, Bureau of Chemistry, Washington, D. C.
Methods for the analysis of monobromated camphor:
Associate referee: C. D. Wright, Bureau of Chemistry, Washington, D. C.
Methods for the eramination of procaine:
Associale referee: A. W. Hanson, U. 8. Food and Drug Inspection Station,
Transportation Building, Chicago, Il.
Methods for the separation and estimation of the principal cinchona alkaloids:
Associale referee: E. O. Eaton, U. S. Food and Drug Inspection Station,
U.S. Appraiser’s Stores, San Francisco, Calif.
Differentiation of Japanese and American peppermint oils:
Associale referee: KE. O. Eaton, U. S. Food and Drug Inspection Station,
U.S. Appraiser’s Stores, San Francisco, Calif.
Testing chemical reagents:
Referee: G. C. Spencer, Bureau of Chemistry, Washington, D. C.
Non-alcoholic beverages:
Referee: W.W. Skinner, Bureau of Chemistry, Washington, D. C.
Eggs and egg products:
Referee: HH. L. Lourie, U.S. Food and Drug Inspection Station, U. S. Appraiser’s
Stores, New York, N. Y.
Food preservatives (saccharin):
Referee: M. G. Wolfe, U.S. Food and Drug Inspection Station, U. S. Appraiser’s.
Stores, New York, N. Y.
Coloring matlers (oil-soluble colors):
Referee: W.¥. Mathewson, Bureau of Chemistry, Washington, D. C.
1921] OFFICERS, COMMITTEES, REFEREES AND ASSOCIATE REFEREES 7
Metals in foods:
Referee: W.F. Clarke, Bureau of Chemistry, Washington, D. C.
Arsenic:
Associate referee: R.M. Hann, Bureau of Chemistry, Washington, D. C.
Pectin in fruits and fruit products:
Referee: H. J. Wichmann, U. S. Food and Drug Inspection Station, Tabor Opera
House Building, Denver, Colo.
Moisture in dried fruit:
Referee: R. W. Hilts, U. S. Food and Drug Inspection Station, U. S. Appraiser’s
Stores, San Francisco, Calif.
Canned foods:
Referee: R. W. Balcom, Bureau of Chemistry, Washington, D. C.
Cereal foods:
Referee: C. H. Bailey, Agricultural Experiment Station, University Farm, St.
Paul, Minn.
Limit of accuracy in the determination of small amounts of alcohol in beers:
Referee: J. R. Eoff, 4104 N. Union Ave., St. Louis, Mo.
Vinegars:
Referee: W.C. Geagley, State Dairy and Food Department, Lansing, Mich.
Flavoring extracts: ;
Referee: W.W. Skinner, Bureau of Chemistry, Washington, D. C.
Meat and meat products:
Referee: C.R. Moulton, University of Missouri, Columbia, Mo.
Separation of meat proteins:
Associate referee: C.R. Moulton, University of Missouri, Columbia, Mo.
Decomposition of meat products:
Associate referee: (Not appointed.)
Gelatin:
Associale referee: C. R. Smith, Bureau of Chemistry, Washington, D. C.
Spices:
Referee: A. E. Paul, U. S. Food and Drug Inspection Station, Transportation
Building, Chicago, Ill.
Determination of shells in cacao products:
Referee: B.H. Silberberg, Bureau of Chemistry, Washington, D. C.
Methods for the examination of cacao butter: j
Referee: W.¥. Baughman, Bureau of Chemistry, Washington, D. C.
Coffee:
Referee: H. A. Lepper, Bureau of Chemistry, Washington, D. C.
Tea:
Referee: R. E. Andrew, Agricultural Experiment Station, New Haven, Conn.
Nitrogen in foods:
Referee: I. K. Phelps, Bureau of Chemistry, Washington, D. C.
8 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No 1
MEMBERS AND VISITORS PRESENT, 1920 MEETING.
Abbott, J. S., Institute of Independent Manufacturers of Margarine, 1212 Munsey
Building, Washington, D. C.
Albrech, M. C., The R. T. French Company, Rochester, N. Y.
Alexander, Miss L. M., Bureau of Markets, Washington, D. C.
Allen, W. M., State Department of Agriculture, Raleigh, N. C.
Alsberg, C. L., Food Research Institute, Stanford University, Calif.
Ames, J. W., Agricultural Experiment Station, Wooster, Ohio.
Anderson, M. 8., Bureau of Soils, Washington, D. C.
Badger, C. H., Bureau of Chemistry, Washington, D. C.
Bailey, C. H., Agricultural Experiment Station, University Farm, St. Paul, Minn.
Bailey, E. M., Agricultural Experiment Station, New Haven, Conn.
Bailey, L. H., Bureau of Chemistry, Washington, D. C.
Balch, R. T., Bureau of Chemistry, Washington, D. C.
Balcom, R. W., Bureau of Chemistry, Washington, D. C.
Ball, C. O., National Canners Association, 1739 H Street, N. W., Washington, D. C.
Barnard, H. E., American Institute of Baking, Minneapolis, Minn.
Bartlett, G. M., Joseph Campbell Co., Camden, N. J.
Bartlett, J. M., Agricultural Experiment Station, Orono, Me.
Bates, Carleton, U. S. Glue Company, Milwaukee, Wis.
Bates, Frederick, Bureau of Standards, Washington, D. C.
Baughman, W. F., Bureau of Chemistry, Washington, D. C.
Beyer, G. F., Bureau of Internal Revenue, Washington, D. C.
Bidwell, G. L., Bureau of Chemistry, Washington, D. C.
Bigelow, W. D., National Canners Association, 1739 H Street, N. W., Washington, D.C.
Bisbee, D. B., U. S. Food and Drug Inspection Station, Old Custom House, St. Louis,
Mo.
Blaisdell, A. C., Bureau of Internal Revenue, Washington, D. C.
Blanck, F. C., National Canners Association, Easton, Md.
Bopst, L. E., Bureau of Chemistry, Washington, D. C.
Bost, W. D., Orange Crush Company, Chicago, III.
Bostwick, E. P., National Canners Association, 1739 H Street, N. W., Washington, D.C.
Bowling, J. D., jr., Bureau of Chemistry, Washington, D. C.
Brackett, R. N., Clemson Agricultural College, Clemson College, S. C.
Bradbury, C. M., State Department of Agriculture and Immigration, Richmond, Va.
Bradshaw, M. A., Bureau of Internal Revenue, Washington, D. C.
Breckenridge, J. E., American Agricultural Chemical Co., New York, N. Y.
Broughton, L. B., University of Maryland, College Park, Md.
Brown, B. E., Bureau of Plant Industry, Washington, D. C.
Buchanan, Miss Ruth, Bureau of Chemistry, Washington, D. C.
Burroughs, Miss L. C., State Department of Health, 16 W. Saratoga Street, Balti-
more, Md.
Butt, C. A., International Agricultural Corporation, Atlanta, Ga.
Carmody, Miss E. L., 79 Chapel Street, Albany, N. Y.
Carpenter, F. B., Virginia-Carolina Chemical Co., Richmond, Va.
Caspari, C. E., St. Louis College of Pharmacy, St. Louis, Mo.
Cathcart, C. S., Agricultural Experiment Station, New Brunswick, N. J.
Cathcart, P. H., National Canners Association, 1739 H Street, N. W., Washington, D.C.
Champlin, S. H., Cape Cod Preserving Corporation, Onset, Mass.
Charlton, R. C., 2343 South Clinton Street, Baltimore, Md.
1921] MEMBERS AND VISITORS PRESENT, 1920 MEETING )
Chesnut, V. K., Bureau of Chemistry, Washington, D. C.
Chittick, J. R., Jaques Manufacturing Company, Chicago, Ill.
Clark, A. W., Agricultural Experiment Station, Geneva, N. Y.
Clarke, W. F., Bureau of Chemistry, Washington, D. C.
Clay, C. L., City Board of Health, New Orleans, La.
Collins, W. D., Geological Survey, Washington, D. C.
Cook, F. C., Bureau of Chemistry, Washington, D. C.
Crawford, C. W., Bureau of Chemistry, Washington, D. C.
Custis, H. H., Bureau of Animal Industry, Washington, D. C.
Davidson, J., Bureau of Chemistry, Washington, D. C.
Davis, R. O. E., Bureau of Soils, Washington, D. C.
Deemer, R. B., Bureau of Plant Industry, Washingion, D. C.
Doolittle, R. E., Transportation Building, Chicago, Ill.
Doran, J. M., Bureau of Internal Revenue, Washington, D. C.
Dunbar, P. B., Bureau of Chemistry, Washington, D. C.
Dunlap, F. L., Monadnock Block, Chicago, Illi.
Durgin, C. B., Bureau of Soils, Washington, D. C.
Ellis, J. T., Bureau of Chemistry, Washington, D. C.
Ellis, N. R., Experiment Station, Beltsville, Md.
Emery, W. O., Bureau of Chemistry, Washington, D. C.
Emmons, F. W., Washburn-Crosby Co., Minneapolis, Minn.
Etienne, Arthur, Agricultural Experiment Station, College Park, Md.
Evenson, O. L., Bureau of Chemistry, Washington, D. C.
Fairchild, J. G., Geological Survey, Washington, D. C.
Ferris, L. W., Bureau of Chemistry, Washington, D. C.
Finks, A. J., Bureau of Chemistry, Washington, D. C.
Fox, Charles, Thomas Building, Hagerstown, Md.
Fraps, G. S., Agricultural Experiment Station, College Station, Texas.
Frary, G. G., State Food and Drug Commission, Vermilion, S. Dak.
Frear, William, Agricultural Experiment Station, State College, Pa.
French, D. M., Alexandria Fertilizer and Chemical Co., Alexandria, Va.
Frisbie, W. S., Bureau of Food and Drugs, Lincoln, Nebr.
Fry, W. H., Bureau of Soils, Washington, D. C.
Fuller, A. V., American Sugar Refining Co., 117 Wall Street, New York, N. Y.
Fuller, F. D., Agricultural Experiment Station, College Station, Texas.
Fuller, H. C., Institute of Industrial Research, Washington, D. C.
Fulmer, H. L., Ontario Agricultural College, Guelph, Ontario, Canada.
Gardiner, R. F., Bureau of Soils, Washington, D. C.
Gascoyne, W. J., 27 South Gay Street, Baltimore, Md.
Geagley, W. C., State Food and Drug Department, Lansing, Mich.
Gersdorff, C. E. F., Bureau of Chemistry, Washington,~D. C.
Gersdorff, W. A., Bureau of Chemistry, Washington, D. C.
Godfrey, Miss R. S., States Relations Service, Washington, D. C.
Goodrich, C. E., Bureau of Chemistry, Washington, D. C.
Gordon, N. E., Agricultural Experiment Station, College Park, Md.
Gore, H. C., Bureau of Chemistry, Washington; D. C.
Gowen, P. L., U. S. Food and Drug Inspection Station, Park Avenue Building, Balti-
more, Md.
Grab, E. G., 838 Woodward Building, Washington, D. C.
10 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Graham, J. J. T., Bureau of Chemistry, Washington, D. C.
Gray, M. A., Pillsbury Flour Mills Company, Minneapolis, Minn.
Griffin, E. L., Bureau of Chemistry, Washington, D. C.
Gross, C. R., Bureau of Chemistry, Washington, D. C.
Haag, J. R., Agricultural Experiment Station, College Park, Md.
Haigh, L. D., University of Missouri, Columbia, Mo.
Halvorson, H. A., State Dairy and Food Commission, St. Paul, Minn.
Hand, W. F., Agricultural College, Agricultural College, Miss.
Hann, R. M., Bureau of Chemistry, Washington, D. C.
Hanson, H. H., State Board of Health, Dover, Del.
Hart, F. L., Bureau of Chemistry, Washington, D. C.
Haskins, H. D., Agricultural Experiment Station, Amherst, Mass.
Haywood, J. K., Bureau of Chemistry, Washington, D. C.
Hazen, William, Bureau of Soils, Washington, D. C.
Hennessy, H. J., State Dairy and Food Department, St. Paul, Minn.
Henry, A. M., State Department of Agriculture, Tallahassee, Fla.
Holmes, A. D., Woodstown, N. J.
Holmes, R. 8., Bureau of Soils, Washington, D. C.
Hoover, G. W., U. S. Food and Drug Inspection Station, Transportation Building,
Chicago, II.
Hopper, T. H., Agricultural College, N. Dak.
Hortvet, Julius, State Dairy and Food Commission, St. Paul, Minn.
FPoward, B. J., Bureau of Chemistry, Washington, D. C.
Howard, C. D., State Board of Health, Concord, N. H.
Huston, H. A., 42 Broadway, New York, N. Y.
Jabine, Thomas, 90 West Street, New York, N. Y.
Jablonski, C. F., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores,
New York, N. Y.
Jackson, R. F., Bureau of Standards, Washington, D. C.
Jacobs, B. R., 1731 H Street, N. W., Washington, D. C.
Jamieson, G. S., Bureau of Chemistry, Washington, D. C.
Janson, J. T., Central Experimental Farm, Ottawa, Canada.
Jarrell, T. D., Bureau of Chemistry, Washington, D. C.
Jenkins, L. J., Bureau of Chemistry, Washington, D. C.
Jinkins, R., Bureau of ‘Chemistry, Washington, D. C.
Johnson, J. M., Hygienic Laboratory, Washington, D. C.
Jones, C. H., Agricultural Experiment Station, Burlington, Vt.
Jones, D. B., Bureau of Chemistry, Washington, D. C.
Jones, R. M., Bureau of Soils, Washington, D. C.
Jones, W. P., Union Trust Building, Washington, D. C.
Kebler, L. F., Bureau of Chemistry, Washington, D. C.
Keenan, G. L., Bureau of Chemistry, Washington, D. C.
Keister, J. T., Bureau of Chemistry, Washington, D. C.
Kellogg, J. W., State Department of Agriculture, Harrisburg, Pa.
Kerr, A. P., Agricultural Experiment Station, Baton Rouge, La.
Kerr, R. H., Bureau of Animal Industry, Washington, D. C.
Kiffenburg, H: B., Interior Department, Washington, D. C.
Kohman, E. F., National Canners Association, 1739 H Street, N. W., Washington, D. Cc.
Kraybill, H. R., Agricultural Experiment Station, Durham, N. H.
1921) MEMBERS AND VISITORS PRESENT, 1920 MEETING 11
Law, T. C., Atlanta, Ga.
LeClerc, J. A., Miner-Hillard Milling Company, Wilkes-Barre, Pa.
Ledman, Miss M. A., Bureau of Markets, Washington, D. C.
Lepper, H. A., Bureau of Chemistry, Washington, D. C. :
Linder, W. V., Bureau of Internal Revenue, Washington, D. C.
Lodge, F. S., Armour Fertilizer Works, Chicago, Ill.
Loomis, H. M., National Canners Association, 1739 H Street, N. W., Washington, D. C.
Lourie, H. L., U.S. Food and Drug Inspection Station, U.S. Appraiser’s Stores,
New York, N. Y.
Lythgoe, H. C., State Department of Public Health, Boston, Mass.
MaclIntire, W. H., Agricultural Experiment Station, Knoxville, Tenn.
Magruder, E. W., F. S. Royster Guano Company, Norfolk, Va.
Mains, G. H., Bureau of Chemistry, Washington, D. C.
Mangels, C. E., Bureau of Chemistry, Washington, D. C.
Manross, Miss L. M., Bureau of Chemistry, Washington, D. C.
Markovitz, L. N., Bureau of Chemistry, Washington, D. C.
Martin, J. B., Bureau of Animal Industry, Washington, D. C.
Mathewson, W. E., Bureau of Chemistry, Washington, D. C.
McBride, R. S., McGraw Hills Company, 610 Colorado Building, Washington, D. C.
McCall, A. G., Agricultural Experiment Station, College Park, Md.
McDonnell, C. C., Bureau of Chemistry, Washington, D. C.
McDonnell, H. B., Agricultural Experiment Station, College Park, Md.
McIntyre, J. D., Bureau of Plant Industry, Washington, D. C.
Mehring, A. L., Bureau of Animal Industry, Washington, D. C.
Mehurin, R. M., Bureau of Animal Industry, Washington, D. C.
Meigs, E. B., Bureau of Animal Industry, Washington, D. C.
Menge, G. A., Libby, McNeill and Libby, Chicago, Ill.
Meredith, E. T., Des Moines, Iowa.
Miner, C. S., Chicago, III.
Mitchell, A. S., Bureau of Chemistry, Washington, D. C.
Mix, Miss A. E., Bureau of Chemistry, Washington, D. C.
Moeller, Otto, Bureau of Chemistry, Washington, D. C.
Moore, C. J., Bureau of Soils, Washington, D. C.
Morawski, A. L., Bureau of Internal Revenue, Washington, D. C.
Morton, J. K., Bureau of Chemistry, Washington, D. C.
Moulton, S. C., Health Department, Washington, D. C.
Munch, J. C., Bureau of Chemistry, Washington, D. C.
Murray, A. G., Bureau of Chemistry, Washington, D. C.
Nelligan, H. P., American Glue Co., Boston, Mass.
Nelson, E. K., Bureau of Chemistry, Washington, D. C.
Nothstine, A. C., Bureau of Chemistry, Washington, D. C.
Olson, G. A., Agricultural Experiment Station, Pullman, Wash.
Osterhout, K. J., Bureau of Internal Revenue, Washington, D. C.
Palmore, J. I., Bureau of Chemistry, Washington, D. C.
Pappe, T. F., Bureau of Chemistry, Washington, D. C.
Parkins, J. H., F. S. Royster Guano Company, Norfolk, Va.
Parkinson, Miss N. A., Bureau of Chemistry, Washington, D. C.
Patten, A. J., Agricultural Experiment Station, E. Lansing, Mich.
Patterson, H. J., Agricultural Experiment Station, College, Park, Md.
12 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Pease, Miss V. A., Bureau of Chemistry, Washington, D. C.
Peters, H. H., Bureau of Standards, Washington, D. C.
Phelps, I. K., Bureau of Chemistry, Washington, D. C.
Phillips, S., Bureau of Chemistry, Washington, D. C.
Pingree, M. H.. American Agricultural Chemical Co., 2343 South Clinton Street, Balti-
more, Md.
Porch, M. B., H. J. Heinz Company, Pittsburgh, Pa.
Power, F. B., Bureau of Chemistry, Washington, D. C.
Price, D. J., Bureau of Chemistry, Washington, D. C.
Proffitt, M. J., Bureau of Standards, Washington, D. C.
Proulx, E. G., Agricultural Experiment Station, La Fayette, Ind.
Rabak, Frank, Bureau of Plant Industry, Washington, D. C.
Rains, Miss Opal, Bureau of Chemistry, Washington, D. C.
Randall, W. W., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Rask, O. S., Bureau of Chemistry, Washington, D. C.
Rather, J. B., Standard Oil Co., New York, N. Y.
Redfield, H. W., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores,
New York, N. Y.
Reed, J. B., Bureau of Chemistry, Washington, D. C.
Reh, Miss Emma, National Canners Association, 1739 H Street, N. W., Washington, D.C.
Reindollar, W. F., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Rhodes, L. B., State Department of Agriculture, Raleigh, N. C.
Rhodes, Mrs. L. B., State Department of Agriculture, Raleigh, N. C.
Richardson, W. D., Swift and Co., Chicago, Il.
Ridgell, R. H., Lexington, Ky.
Roark, R. C., General Chemical Company, Baltimore Works, Baltimore, Md.
Roberts, O. E., jr., Chemical Warfare Serviée, Washington, D. C.
Robinson, C. H., Central Experimental Farm, Ottawa, Canada.
Roethe, H. E., Bureau of Chemistry, Washington, D. C.
Ross, B. B., Polytechnic Institute, Auburn, Ala.
Ross, W. H., Bureau of Soils, Washington, D. C.
Roth, G. B., 25th and E Streets, N. W., Washington, D. C.
Ruderman, M., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores,
New York, N. Y.
Runkel, H., U. S. Food and Drug Inspection Station, Federal Office Building, Min-
neapolis, Minn.
Runyan, E. G., 419 Tenth Street, N. W., Washington, D. C.
Russ, R. F., Bureau of Chemistry, Washington, D. C.
Russell, G. A., Bureau of Plant Industry, Washington, D. C.
Sale, J. W., Bureau of Chemistry, Washington, D. C.
Sample, J. W., State Department of Health, Nashville, Tenn.
Savage, H. E., Honolulu, T. H.
Schertz, F. M., Bureau of Plant Industry, Washington, D. C.
Schultz, Alfred, Bureau of Chemistry, Washington, D. C.
Schulze, W. H., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Scott, Miss D. B., Bureau of Chemistry, Washington, D. C.
Semple, A. T., 710 E Street, N. W., Washington, D. C.
Sherwood, F. W., Agricultural Experiment Station, Raleigh, N. C.
Shrader, J. H., Bureau of Plant Industry, Washington, D. C.
Shulenberger, F. W., Eimer and Amend, New York, N. Y.
Sievers, A. F., Bureau of Plant Industry, Washington, D. C.
1921] MEMBERS AND VISITORS PRESENT, 1920 MEETING 13
Silberberg, Miss B. H., Bureau of Chemistry, Washington, D. C.
Skinner, J. J., Bureau of Plant Industry, Washington, D. C.
Skinner, W. W., Bureau of Chemistry, Washington, D. C.
Smalley, F. N., Southern Cotton Oil Co., Savannah, Ga.
Smith, A. M., Agricultural Experiment Station, College Park, Md.
Smith, C. M., Bureau of Chemistry, Washington, D. C.
Smith, Miss J. K., Bureau of Chemistry, Washington, D. C.
Smith, Miss S. L., States Relations Service, Washington D. C.
Smither, F. W., Bureau of Standards, Washington, D. C.
Snyder, E. F., Bureau of Plant Industry, Washington, D. C.
Soule, A. M. G., State Department of Agriculture, State House, Augusta, Me.
Spear, A. A., Bureau of Internal Revenue, Washington, D. C.
Spencer, G. C., Bureau of Chemistry, Washington, D. C.
Spurr, F. A., Bureau of Animal Industry, Washington, D. C.
Stephenson, C. H., Bureau of Chemistry, Washington, D. C.
Stevenson, A. E., National Canners Association, 1739 H Street, N. W., Washington, D.C.
Strowd, W. H., State Department of Agriculture, Madison, Wis.
Sullivan, A. L., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Swicker, V. C., Bureau of Standards, Washington, D. C.
Taber, W. C., U.S. Food and Drug Inspection Station, Federal Building, Buffalo, N.Y.
Taistra, Theodore, 205 Third Avenue, New York, N. Y.
Taylor, A. E., Bureau of Chemistry, Washington, D. C.
Taylor, E. P., 543 Conway Building, Chicago, Ill.
Taylor, J. J., 130 State Capitol, Atlanta, Ga.
Taylor, J. N., Bureau of Animal Industry, Washington, D. C.
Thatcher, A. S., Loose-Wiles Biscuit Co., Washington, D. C.
Thom, Charles, Bureau of Chemistry, Washington, D. C.
Thompson, E. C., 108 Hudson Street, New York, N. Y.
Thompson, H. L., 218 East 37th Street, New York, N. Y.
Thornton, E. W., R. B. Davis Co., Hoboken, N. J.
Toll, J. D., The American Fertilizer, 1010 Arch Street, Philadelphia, Pa.
Ullrich, Miss J. R., 23 Beaver Street, New York, N. Y.
Valaer, Peter, jr., Bureau of Internal Revenue, Washington, D. C.
Veitch, F. P., Bureau of Chemistry, Washington, D. C.
Viehoever, Arno, Bureau of Chemistry, Washington, D. C.
Vollertsen, J. J., Morris & Co., Chicago, III.
Walker, P. H., Bureau of Standards, Washington, D. C.
Walton, G. P., Bureau of Chemistry, Washington, D. C.
Waterman, H. C., Bureau of Chemistry, Washington, D. C.
Weber, F. C., Bureau of Chemistry, Washington, D. C.
Weems, J. B., State Department of Agriculture, Richmond? Va.
Weir, W. W., 236 Southern Building, Washington, D. C.
Wessels, P. H., Agricultural Experiment Station, Kingston, R. I.
Wiley, H. W., Woodward Building, Washington, D. C.
Wiley, R. C., Agricultural Experiment Station, College Park, Md.
Wiley, S. W., Wiley & Co., Inc., Calvert and Read Streets, Baltimore, Md.
Williams, C. C., National Canners Association, 1739 H Street, N. W., Washington, D. C.
Wilson, J. B., Bureau of Chemistry, Washington, D. C.
Wilson, J. O., Baugh Chemical Company, Baltimore, Md.
14 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Wilson, S. H., State Department of Agriculture, Atlanta, Ga.
Wilson, Mrs. S. H., State Department of Agriculture, Atlanta, Ga.
Wilson, S. M., Baugh & Sons Co., Baltimore, Md.
Winant, H. B., Agricultural Experiment Station, College Park, Md.
Wright, C. D., Bureau of Chemistry, Washington, D. C.
Young, H. D., Bureau of Chemistry, Washington, D. C.
PRESIDENT’S ADDRESS’.
THE APPLICATION OF THE THEORY OF PROBABILITY
TO THE INTERPRETATION OF MILK ANALYSES.
By H. C. Lyrucor (State Department of Public Health, Boston, Mass.),
President.
In 1914 I published an article upon the composition of milk?. The
article resulted from the compilation of the analyses of about 500 samples
of milk of known purity of which 63 represented herds and the balance
represented milk from individual cows. The conclusions recorded in
the article were based upon the best judgment of the results obtained
and were not intended to represent the last word upon milk analysis
and milk composition, neither were they intended to give to milk handlers
the right to adulterate the product they sold until it conformed with
the worst milk that could be produced by a cow or a small herd of cows
and to use the conclusions of the article as evidence in court that the
adulterated milk was pure.
The adulteration of milk with water is risky, and will eventually be
detected although the profits are high and the detection of small quan-
tities of added water is difficult and, in many instances, impossible. The
work upon milk serum reported by Nurenberg in 1914° and 1915* has
served as a supplement to the conclusions in the above-mentioned ar-
ticle upon the detection of added water, and this phase of the question
needs no elucidation at present.
Adulteration by the removal of cream or, in other words, by the
addition of skimmed milk is highly profitable, is difficult of detection
and probably is not uncommon. Because of the demand for cream,
there is a large surplus of skimmed milk left upon the dealers’ hands
and it is much more profitable to pass this on to the consumer as whole
milk at 19 cents per quart than as skimmed milk at 5 cents per quart,
particularly since the public has not shown any desire to purchase this
1 Presented Tuesday morning, November 16, 1920, as special order of business for 11.30 o'clock.
2 J. Ind. Eng. Chem., 1914, 6: 899.
3 J. Assoc. Official Agr. Chemists, 1916, 2: 8.
‘ Tbid., 145; Rept. Mass. State Dept. Health, 1915, 517.
1921] LYTHGOE: PRESIDENT S ADDRESS 15
skimmed milk at the prices at which the dealers desire to sell, and this
skimmed milk, therefore, is practically a waste product.
During the recent milk price-fixing regime of the Federal Milk Com-
mission for New England, the dealers bought from the producers at a
price based upon a fat content of 3.5 per cent and, presumably, the
retail price was based upon the same fat content. Because a premium
was paid for milk with a fat content above 3.5 per cent the producers
began to ship milk containing from 3.8 to 4.0 per cent of fat. This milk
was then presumably diluted with skimmed milk to bring the fat down
to 3.5 to 3.7 per cent and, occasionally, to 3.3 to 3.4 per cent. To sub-
-stantiate this statement, reference is made to Chart I, which shows the
relation between the solids and fat of: (1) Milk of known purity (from
that portion of a curve of 1000 analyses from individual cows lying
between 11.5 and 13.5 per cent of solids); (2) milk from the so-called
large dealers in Massachusetts taken during 1913 and 1914; and (3),
milk from the same dealers from December 1917 to July 1918. It should
be carefully noted that the curve representing the commercial milk of
1913-1914, parallels that of the known-purity samples but the fat is
slightly lower in the commercial samples. The commercial samples of
1918 show a remarkable unanimity in fat content, irrespective of what
the solids may be. This can be explained by the presence of skimmed
milk in the latter samples. Since the protein-fat ratio in these samples
was less than 1.0, it is evident that the interpretation of milk analyses
must be different when the sample represents the combined milk of a
number of dairies than when it represents the milk of but one cow or
of a small dairy. It should be stated that when the results of the 1919
analyses were not compiled collectively but each dealer’s milk was com-
piled separately, no such unanimity of results was obtained.
sieecesgecvanstensttftais?
av Bet ns |
Av
TTA
aeAN
OBme> Swe
is
:
Lh
i
HHS
tere]
a5
aa
Pae
re
a
<0
Tas)
a
re
HHA
anx
oP a
Sa
SPEORSAo
oo LLP yee
-00
Use WIS jageo 2S 1250 says /3.00 13-90
CHarT 1 Souns ~7&R Cewr
16 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
In the conclusions of the article previously referred to, the following
statements occur’:
‘*The protein-fat ratios in all cases have been less than 1. If this figure
exceeds 1, skimming is indicated, the amount being greatest in samples
posséssing the highest ratio.
“Tf the protein-fat ratio is less than 0.7 or the percentage of fat in
the solids is above 35.0, samples may be declared watered by a low
refraction of the serum, not necessarily below the minimum for all samples
of known purity. This is particularly true when dealing with herd milk.’’
The legal mind has attempted to misconstrue the first statement by
claiming that it is capable of converse construction and means that if
the protein-fat ratio is less than 1.0 the milk is pure. The falseness of
this contention can be understood easily by any one of average mentality,
particularly so when one realizes that the average market milk has a
protein-fat ratio of 0.82 and the mixed milk of the Guernsey and Jersey
type of cows has a protein-fat ratio as low as 0.6. Considerable skimmed
milk, therefore, can be added to such milk before the ratio of proteins
to fat reaches 1.0. Milk with a fat content of 4 per cent and a protein-
fat ratio of 0.82 can be adulterated with 15 per cent of skimmed milk
and still possess a protein-fat ratio of less than 1.0. It is evident, there-
fore, that the use of a protein-fat ratio of less than 1.0 as a criterion that
milk is not skimmed is faulty and, therefore, when dealing with the
composite milk of a number of herds it is reasonable to use a lower figure
for the detection of skimming, particularly so if other figures point to
the fact that the sample, before being tampered with, naturally had a
low or average protein-fat ratio.
The second quotation is of interest in that if milk of a low protein-fat
ratio naturally possesses a high refracting serum, milk with a high refract-
ing serum naturally possesses a low protein-fat ratio. In other words,
it is not usual for milk to possess both a high refraction of the serum and
a high protein-fat ratio.
In the samples referred to, the copper serum refraction and the pro-
tein-fat ratio were determined upon 362 samples. The average protein-
fat ratio has been computed for each 0.1 variation in the serum refraction,
each computation representing from 1 to 24 samples averaging 10.4.
The results are shown in Chart II. The heavy, flattened curve shows
the resultant of this relation if more samples had been included. In all
cases when the average protein-fat ratio was above 0.85 the average
refraction was below 37. In all cases when the refraction was above 38.0
the average protein-fat ratio was below 0.81. Deductions from the flat-
tened curve indicate that mixtures of milk from many dairies with a
copper serum refraction above 38 would have a protein-fat ratio of less
1 J. Ind. Eng. Chem., 1914, 6: 907.
1921] LYTHGOE: PRESIDENT ’S ADDRESS 17
than 0.80 and, therefore, it may be assumed that milk representing a com-
posite sample from many dairies, with a protein-fat ratio of 0.90 or
above, has in some manner been diluted with skimmed milk, particularly
so if the refractive index of the copper serum is 38 or above.
26 85 USES E S008 Rees Pee ee BEERS Eas
a Ws HEEe HHH imjate le iafafalmletaaeiaatelsinletal
PCN 2am oaa5 Hee PEELE H
cp aia sEEcEEE BEE a
20 vs fea SouGESEEREEEEEEREEE SoSnGeRn8 SESS S0Ee0588
NNN cetera eartal Iabadebedebke CO Coo
| SnaaeER HDaSOSeERee
Py Na ro Chere (Semin | ez Pe iia)
725 ASS. ~ Se nan
85 See eee SaaRneae rj oy
PROSE 0000 Vib. “SGESRe eRe SR eee a
é SRDS U50,) = EoUDD PEE
N PEEL ZN et Hea
El SESE G/ hGb VER! on UE ee ee
+80 Far Ww A ) 6,0 0RE PE
AN SUES NY ACA Re A
inn BWA! (a Sa0 | fefebea
Se a le
Vy Se ee
© 75 POOLE LLL LLL ELE LN i Ee
>) GOO oo HBoa
ee oad inaonananead HA Coc
Sj Poo eae oe paar dane] HARA S
Gea tye E err Ce rere ret CNS
afm papebanis | mfeyefal ale) aan ‘ean
DAOES IAS ae es PA
ese roe |
65 Foe 12 ieee
BEDESenSone rho Se
SERED ESSEe co a
BREE EEE EE
6o CELI TT petepapafia] Ci Livi TTI TET
"360 370 88.0 320 429 404
CHART aE SeRum Perracriow
The foregoing statements are from an article prepared in 1919 and
withheld from publication in order that a more detailed study might
be given to the protein-fat ratio of milk and its relations to various other
milk ingredients. As first shown by Van Slyke!, the protein-fat ratio is
a characteristic of the breed and in all natural milk is less than 1.0; if it
exceeds 1.0, skimming is indicated. This has been confirmed by work of
the Massachusetts Department of Public Health. Other variations in
the protein-fat ratio, possibly of minor character but, nevertheless, of
significance, are in variations with changes in solids, fat and serum
refraction, as well as variations in herd milk compared with milk from
individual cows. All these variations have a bearing upon the interpre-
tation of analyses when the possibility of skimming is to be considered
and the protein-fat ratio is less than 1.0.
In order to properly compile and study these variations, the arithmetic
probability paper of Hazen and Whipple® was employed. The ordinates
of this paper may be either arithmetic or logarithmic but the abscissae
constitute a probability scale of such nature that if ‘‘the items of a series
of observations plotted on this paper fall in a straight line it indicates
Peo Am. Chem. Soc., 1908, 30: 1166.
J. Frank. Inst., 1916, 182: a7 205.
18 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
that they form a probability series; that is, they occur according to the
laws of chance.’’ This paper is of value for such observations as age of
scholars, rainfall, flow of streams, death rates, bacteria counts, etc. As
a rule, the arithmetic paper is preferable for most observations, but in
some instances the observations plot in a curved line, as in the case of
certain bacterial observations. For such observations, the logarithmic
paper is preferable.
In all statistical work a large series of observations is desirable for
satisfactory results, but by the use of this paper, in the case of a relatively
small number of observations, it is possible to ascertain whether or not
the observations are of such a nature that conclusions can be drawn from
them. In other words, this paper eliminates the freaks from a series of
observations. An example of the use of this paper in connection with the
examination of food was shown by L. J. Nurenberg in his report to
this association on dairy products in 1915.1
In carrying out this study, I had at my disposal the analyses of the
milk of over 1000 individual cows, and of 116 herds, the samples being
milked in the presence of an inspector or a chemist of the Massachusetts
Department of Public Health. The cows were representations of all the
usual dairy breeds and crossbreeds; they were of various ages; repre-
sented all periods of lactation, and the samples were collected at all seasons
of the year.
A study made in 1919 of the herd milk figures gave the surprising
information that, although the average protein-fat ratio is about 0.83, 11
per cent had a protein-fat ratio above 0.90, and except for the maximum
value 0.96 and the 3 minimum values 0.55, 0.56 and 0.60, the data plotted
approximately upon a straight line on the probability paper. A sub-
division of these figures into milk below 12 per cent and above 13 per
cent in solids showed a much larger percentage of milk with high pro-
tein-fat ratio in the case of those samples below 12 per cent than in the
case of the entire number. For example, 3 per cent of the samples above
13 per cent in solids had a protein-fat ratio above 0.90, and 13 per cent
of those below 12 per cent in solids were above 0.90, and of those between
12 and 12.9 per cent solids, 20 per cent were above 0.90. This compilation
of results on samples below 12 per cent in solids, representing but 13
samples, does not plot in a straight line, and, therefore, definite con-
clusions can not be drawn from those figures; but from the similarity
beween the different plots with the same general direction in all cases,
it is evident that the percentage of samples with high protein-fat ratio
in herd milk with solids of less than 12 per cent must necessarily greatly
exceed that in herd milk above 12 per cent in solids. Tt appears from the
figures in Chart III that it is impracticable to call commercial milk,
1 J. Assoc. Official Agr. Chemists, 1916, 2: 145.
19
-90
between 0
fat ratio
S ADDRESS
1m-
’
PRESIDENT
LYTHGOE
“‘skimmed’’, if relying entirely upon a prote
1921]
and 0.98.
HNUUQENEONOEEEUETL 7 [
7: i a i ee ay
| jenn son
i i sean SURES if 5 al
\! c
i “ Ht E
} a
HH mil iS c
He faite ts KS
ial oh oH ops i Re i
HEN St aR aT
ae SHUHHEE
HIRE
ale -}
a 30 40
i)
a
a
iN N
a eur
aa LL
i 4 Hi oe Ht
Oh ge 4 ae - pe eae
i |
rat a
Hi EH
RTT creamy one Ome nr ie Fercenr oF St.
CG
CHART Are eS ~ Eoneoe nr sacipeecoeas
5 8 sgn ey
OLY hel VIL Okey
20 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
re] ; a 3 5 rs H #f 33 a
-30 0 50 “60 70 80 90 -/00
CHART PRorEW- Far AATig Heb 10-10-20.
A more complete study of the protein-fat ratio was made, specifically
in relation to its variation with breed, solids, fat, and copper-serum
refraction, and the comparison between milk from individual cows and
from herds. Chart IV (cn the probability paper) and Chart V (on ordinary
arithmetic paper for comparative purposes) give the comparison of milk
from 746 individual cows with that from 116 herds. In the plot on the
probability paper, it will be noticed that while a large number of low
protein-fat ratios found in individual cows disappear in herd milk, a
smaller number of the high ratios disappear in the herd milk. This is in
marked contradistinction to other figures, such as solids and fat taken
from analyses of the same samples, in which cases, about equal quantity
of high and low figures in milk from individual cows are not to be found
in herd milk. This is further emphasized by the fact that the median,
which in these figures closely approximates the average, is about 0.80,
while the arithmetic mean of the maximum and the minimum is about
0.70, showing a far greater preponderance of milk with a high protein-
fat ratio than with a low protein-fat ratio. It is possible that the under-
lying cause for this condition is due to the preponderance of certain breeds
of cattle.
The 746 samples from individual cows were obtained econ to
breeds as follows:
167 from pure-bred Holsteins;
126 from pure-bred Ayrshires and a few grades;
180 from pure-bred and grades of the Jersey and Guernsey types;
273 from grade cows of the Holstein tyne.
21
PRESIDENT’S ADDRESS
LYTHGOE
1921]
Bassi
SEEEES
Varigrion in PReTEW CREE win BREED.
O1k Wy Lb -N1FLOe
wm 6.
SAMPLES,
CHA Ter YL ree Comang ove Enpreers avis PERCENT OF
£4.00
-90
80
Leo
ine
7
£22
Seon HES
is
NI
* ore ee “ be - APPL OMe/
8 R $
= ee
pee
Hee
~PmctaBarry SCALES
Anmacr
th the breed first po
zo 30 49 SO 6
. Consuming One Engmecrs. NY IP LROLVT OF SAP PLES
inted out by
is clearly demonstrated in Chart VI,
io wi
i tein-fat rat
on in pro
The variati
Van Slyke
ly stated
, as previous
and
milk with the lowest
io,
in-fat rat
highest prote
ing milk with the
giv
breed
the Holstein
giving
the cows of the Jersey and Guernsey types
protein-fat ratio. The milk from the grade Holstein cows is shown on
Chart VII, and closely approximates that of the Holstein breed. It should
be noted that the percentage of the samples above 0.90 in the different
22 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
breeds follows very closely the variation in the average protein-fat ratio
of that herd. Thus, 25 per cent of the samples from the Holstein cows
(average protein-fat ratio 0.87 according to Van Slyke), 13 per cent of
the milk from the Ayrshire cows (average protein-fat ratio 0.82), and
5 per cent of the milk from the Jersey cows (average protein-fat ratio
0.64) were above 0.90. A comparison of the median with the arithmetic
mean of the highest and lowest is of interest in these figures, giving
further evidence that the prevalence of high protein-fat ratios is due to
breeding, and is as follows:
Comparison of the median with the arithmetic mean.
BREED MEDIAN ARITHMETIC MEAN OF HIGHEST AND LOWEST
Jersey 0.70 0.685
Ayrshire 0.77 0.74
Grade Holstein 0.81 0.745
Holstein 0.82 0.70
It is evident that the question of breeds must be eliminated if figures
below 0.99 are to be used in detecting skimming. Therefore, the protein-
fat ratio was studied in respect to its variations with variations in other
milk constituents, and it was found that the protein-fat ratio was to
some extent a function of the fat, of the copper-serum refraction, and
to a less extent of the solids.
Lode a 9 Ets 99 ~ 929 S829P 90
90 - Ht 30
a
bo — 400
970 - 20
kt in
g ie Se
\.60 Hee
rv nt + loo
{ a Hi = T ae
N Sat E aie
q Seeats: = Seaentie
§.70 TH 90
v HH t if
| tf WEEE
R euBeel
7 = cpitnees ne — ae
60 a Hitt oa ; hoo
=" 2 Ht + +t inane
HH tt ;
oe i i tt Ht t ae
=e + ‘
eh i it iH
= —e + i, = iS
6 ocr ay 60 72 60 oo «OS oo pao ash?
Pax s cd Ro io oo
CHAR TLL rr: (Coomera Onrrters ISA OPERA NOS 401 POLES: Anmacnc-Prosaniirr Scaies '
23
PRESIDENT S ADDRESS
LYTHGOE
1921]
cs)
Ss
aS
OW ey hhef “NAIL Obey
45
deuce
sh
:
Anmacne-Prossegy.
a et
ongmeers
Q,
CHART LE ro. Crs oe
JF
OLA OUUDEDODOUONNND RDO OOO
" Onebeg hte = 7L0 wey”
f cer-
ion 0
1S
VII, LX and-X show a divi
with groups above and below 12 per cent of sol
3
Some of the plots in Charts VI
tain milk samples
ds,
i
lids have a much
m so
.
and it will be noted that those below 12 per cent
greater percentage of samples with protein-fat ratio above 0.90. This
is also evident from a perusal of the results of herd samples in Chart III.
In Chart VIII
th the varia-
lids within narrow limits, showing that as the solids decrease
wi
jation in protein-fat ratio
the var
is given
ion in so
t
24 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
the protein-fat ratio increases. Three hundred and eighty-seven samples
are represented in this chart. There were 312 samples with fat percentages
between 2.9 and 3.7. They were subdivided into three groups with fat
variation of 0.3 each: namely, 2.9 to 3.1 per cent; 3.2 to 3.4 per cent;
and 3.5 to 3.7 per cent. The results of this compilation are shown in
Chart IX. The samples with fat between 2.9 and 3.1 per cent seem to
fall into a somewhat different class than the others, and about half of
the samples had a protein-fat ratio above 0.90, which is the highest
percentage of any of the groupings studied. Of the samples with fat
between 3.2 and 3.4 per cent fat, 24 per cent had a protein-fat ratio above
0.90, and of the samples between 3.5 per cent and 3.7 per cent fat, 19
per cent had a protein-fat ratio above 0.90. It is in commercial milk with
fat content between 3.2 and 3.7 per cent that the greatest difficulty is
encountered in the detection of the presence of skimmed milk.
To further study the relation beween protein-fat ratio and copper-
serum refraction, the protein-fat ratio of milk with copper-serum refrac-
tion between 37.5 and 38.3 from 248 cows and 52 herds was plotted and
is shown in Chart X. This chart also illustrated again the preponderance
of high protein-fat ratios in contradistinction to those of low protein-
fat ratio, and also shows that more low and less high protein-fat ratio
figures disappear in herd milk. Note, however, that 13 per cent of the
herd samples, copper-serum refraction 37.5 to 38.3, were above 0.90 in
protein-fat ratio, thus showing the fallibility of the conclusion in the
preliminary discussion of this question, drawn entirely from a study of
averages.
PTT TSA
SEEN
INTUUUUEGUOTIEE
=
os
=
=
=
=
=
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=
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=
=
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i 7 o
G HAREM [wre Coury cra Engineers OPLRCENT OF SAMPLES
1921| LYTHGOE: PRESIDENT ’S ADDRESS 25
‘AUM EPPACT/ON.
Gen Geog
HANNA
PUTTS
Copper
g
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TTT
SUN AUUTNUTAIL
‘Creare Ke. comang cna Dupreers, uy EUPERCAVT. OF SOM PLES
To study this variation in narrower ranges, Chart XI was prepared,
showing the variation in protein-fat ratio with the variation in copper-
serum refraction: 77 samples, copper-serum refraction 37.6 to 37.8; 82
samples, copper-serum refraction 37.9 to 38.1; 87 samples, copper-serum
refraction 38.2 to 38.4. In general, these plots show that as the copper-
serum refraction increases the protein-fat ratio diminishes, but in each
plot it will be noticed that from 13 to 18 per cent of the samples were
above 0.90 in protein-fat ratio. It may be possible to apply these data
to the interpretation of analyses, but, in order to obtain another factor,
the probability of variation between copper-serum refraction and fat
was computed for certain fat percentages and will be found in Chart XII,
showing that to some extent the serum refraction is a function of the
fat percentage.
It is manifest that conclusive opinions relative to the removal of cream
can not be given in the cases referred to unless they occur so extensively
that the probability of their natural occurrence has been eliminated by
an overwhelming number of samples of unusual composition. For com-
parative purposes and for ease of study, that portion of the variation of
the protein-fat ratio between 0.85 and 0.99, as compared with variation
of serum refraction, fat and solids, together with the variation of the
serum refraction between 37 and 39, as compared with the variation in
fat, will be found in Chart XIII. Since the plots were prepared largely
from analyses of individual cow’s milk, they should give sufficient margin
of safety for conclusive opinions.
26 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
1-00, os “ St 20 $0 40 30 @0 70" 60 90 95 99 as 2295 55
r
.90 - .20
160 400
a +
Ny
‘
K 90 0
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8,
CopreR es:
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abe sao wae
Blas ’ é 7 20 3O 40 SO 60 éo 90
CHART RAI Consuimg Cn Engineers Ny 193 PERCENT OF SAMPLES, Animesenc-Prosasuiry SCALEg
The following figures show the analyses of three samples of milk of
known purity and the computed analyses resulting from assumed skim-
ming.
Effect of skimming on protein-fat ratio and copper serum.
PROTEIN- FAT CORRESPONDING
COPPER CREAM
SOLIDS FAT PROTEINS FAT TO SOLIDS NOT
REFRACTION REMOVED
RATIO LESS THAN
per cent per cent per cent degrees per cent per cent
12.07 3.55 2.68 0.76 38.3 None 3.30
11.42 3.00 2.68 0.89 38.3 15 A 2.90
11.22 2.80 2.68 0.96 88.3 2) B 2.80
12.40 3.60 2.99 0.83 38.0 None 3.60
12.10 3.30 2.99 0.91 38.0 8 C 3.40
11.90 3.10 2.99 0.96 38.0 14 D 3.20
13.30 4.00 2.86 0.72 39.5 None 4.10
12.50 3.20 2.86 0.89 39.5 20 E 3.60
12.30 3.00 2.86 0.96 39.5 25) 3.50
From Table 3 in the publication previously referred to!, showing the
1J. Ind. Eng. Chem., 1914, 6: 903.
1921] LYTHGOE: PRESIDENT’S ADDRESS 27
expected relation between the fats and solids, samples B, E, and F are
highly suspicious of being skimmed. The protein-fat ratio alone indicates
nothing except suspicion in the cows of examples B, D and F. The fol-
lowing figures are computed from Chart XIII and show the probability
expressed in per cent of these figures occurring.
Probable ratio between proteins and fat.
A, 15 PER CENT SKIMMED
Probability of per cent
Protein-fat 0.89 occurring with copper refraction of 38.3.................. 16
Protein-fat 0.89 occurring with solids () ea ee Peo cone nara c 30
Protein-fat 0.89 occurring with fat OLS SAOO irs 8 Sect Risers 55
Copper refraction 38 .3 occurring with fat Oi AU, Varrmecoucarcaodon 6
B, 21 PER CENT SKIMMED
Protein-fat 0.96 occurring with copper refraction of 388.3 ................ 5
Protein-fat 0.96 occurring with solids Of A Done incre aati 11
Protein-fat 0.96 occurring with fat OLsi23SOm encom 20
Copper refraction 38 .3 occurring with fat DPEZESO ectstseh eae 6
C, 8 PER CENT SKIMMED
Protein-fat 0.91 occurring with copper refraction of 38.0................. 15
Protein-fat 0.91 occurring with solids Ob 2alOW Cciascociesenicon 19
Protein-fat 0.91 occurring with fat Mis Blea Ve mesine pone Somer
Copper refraction 38 .0 occurring with fat OL MSE SO! wists ciety stele eiekegs 26
D, 14 PER CENT SKIMMED
Protein-fat 0.96 occurring with copper refraction of 38.0................. 6
Protein-fat 0.96 occurring with solids Of FLW OO Geers eoctcincs toe
Protein-fat 0.96 occurring with fat. OPM SLO srr peranieedoren cecil
Copper refraction 38 .0 occurring with fat OLS 1 O) Pee encrtiestetesstecro Lt
E, 20 PER CENT SKIMMED
Protein-fat 0.89 occurring with copper refraction of 39.5.............0... 10
Protein-fat 0.89 occurring with solids OfsD DOR Gee cisemissertsee ace
Protein-fat 0.89 occurring with fat Of SE20 Fras Tee Cocoon. 34
Copper refraction 39 .5 occurring with fat Of, 13: 20 Eas, desis cores 0.6
F, 25 PER CENT SKIMMED
Protein-fat 0.96 occurring with copper refraction of 39.5.................. 4
Protein-fat 0.96 occurring with solids OLDE SO sep ceetoi rer tease 8
Protein-fat 0.96 occurring with fat Ole OO etry severain cioers tere) see
Copper refraction 39 .5 occurring with fat OLS OOK, srveplepusiescntone 0.07
In the cases of examples E and F, the very low frequency of these
copper-refraction and fat figures occurring at the same time, taken with
the other data, is sufficient evidence to call the samples skimmed with-
28 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
out any other data. In the cases of A and B, notwithstanding the high
frequency of the occurrence of the observed protein-fat ratio compared
with the fat, such samples may be declared skimmed if obtained from
one dealer in sufficient quantities to overcome the probabilities of the
copper-refraction-fat comparison and the copper-refraction comparison
with the protein-fat ratio being natural. In the case of example C, the
sale of such milk should be almost a continual performance before skim-
ming could be proved and in the case of example D, at least 15 per cent
of the samples obtained from the dealer should be like the example.
CONCLUSIONS.
A protein-fat ratio of less than 1.0 is no criterion that milk is not adul-
terated.
The protein-fat ratio is a function of the solids, fat and serum refrac-
tion, as well as of the breed, and when less than 1.0, if used in the inter-
pretation of analyses, should be studied in relation to such figures of
which it is a function.
Milk representing the mixed milk of many dairies can be declared
skimmed when the protein-fat ratio is less than 1.0; provided, however,
that other analytical data are obtained to substantiate the conclusion;
and provided, further, that a sufficient number of samples has been
obtained to exclude the probability of the natural occurrence of such
milk.
Owing to the greater prevalence of high protein-fat ratios compared
with low protein-fat ratios in milk from the average dairy herds, it is
inaccurate to assume that the mixed milk of a number of herds would
not greatly exceed in protein-fat ratio that of the average protein-fat
ratio of the analyses on record.
In comparing the composition of milk from individual cows with milk
from herds, both the maximum and minimum figures obtained from
individual cows, as a rule, are not found in herd milk; the protein-fat
ratio, however, is an exception for but few of the highest figures so dis-
appear because of greater frequency of protein-fat ratios above the
average.
FIRST DAY.
MONDAY—MORNING SESSION.
The thirty-sixth annual convention of the Association of Official Agri-
cultural Chemists was called to order by the President, H. C. Lythgoe,
of Boston, Mass., on the morning of November 15, 1920, at 10.00 o’clock
at the New Willard, Washington, D. C.
REPORT ON WATER.
By J. W. Sate (Bureau of Chemistry, Washington, D. C.), Referee.
Last year a method for the determination of iodine in the presence
of chlorine and bromine! and a method for the determination of bromine
in the presence of chlorine but not iodine? were tested, and adopted by
the association as tentative methods.
This year a method for the determination of bromine in the presence
of both chlorine and iodine’ has been tested and is as follows:
BROMINE IN THE PRESENCE OF CHLORINE AND IODINE’.
APPARATUS.
Two, tall form, glass-stoppered Dreschel gas
washing cylinders.
An ordinary glass cylindes.
Joined as in Fig. 1.
REAGENTS.
(a) Ferric sulfate crystals.
(b) Alkaline sodium sulfite solution —Dissolve
4 grams of sodium sulfite and 0.8 gram of sodium
carbonate in 100 cc. of water.
(c) Chromium trioxide crystals.
(d) 3% solution of hydrogen peroxide.
(€) Potassium iodide crystals.
(ft) N/20 thiosulfate.
REACTIONS.
Fe, (SOs)3 +2 KI=2 FeSOs+Io+K2S0j. Fic. 1. AppaRATus.
2 CrO;+6 HBr=Cm03+3 H20+3 Br. A—Reaction Cylinder. B and C—Absorp-
2 HeCrO4+3 HeO2=Cr03+302+5 H20. tion Cylinders. E—Rubber Connections.
NaeSO3+2 Br+H20 =2 HBr+NaeSO4.
1J. Assoc. Official Agr. Chemists, 1921, 4: 380.
2 Thid., 381.
3 J. Ind. Eng. Chem., 1920, 12: 358.
29
30 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
DETERMINATION.
Introduce 10 cc. of the sample into a distillation flask, adjust the volume to about
75 ec. and add 1.5-2.0 grams of ferric sulfate. Distil off the liberated iodine with
steam, discarding the distillate. Empty the residue in the distillation flask into a
beaker; heat to boiling, add a few drops of methyl orange, and precipitate the iron
with ammonia. Avoid an excess of ammonia, as a precipitate of calcium oxide is
bulky and difficult to wash. Filter off the iron hydroxide; wash with hot water, and
evaporate the filtrate to dryness, or nearly so. During the evaporation do not allow
the solution to become acid from the hydrolysis of magnesium chloride.
From this point, proceed as described in the method for bromine in the presence of
chlorine but not iodine', beginning under “‘Determination”, line 2, “Charge the reac-
tion cylinder A, Fig. 1, by introducing, etc.”
Briefly, the method consists of oxidizing iodine with ferric sulfate and
distilling off the liberated iodine with steam. After removing iron from
the residual liquid, the bromine is oxidized with chromic acid, and the
liberated bromine aspirated into an alkaline solution of sodium sulfite.
The oxidation is repeated and the bromine aspirated into a solution of
potassium iodide, the iodine liberated by the bromine being titrated with
a standard solution of sodium thiosulfate.
Synthetic samples of brine were forwarded to eleven analysts who had
expressed a desire to cooperate. However, only five submitted their
results in time for this report.
The synthetic brine sent to cooperators contained 0.080 gram of
bromine per 10 cc. It contained also 0.080 gram of iodine, 1.0 gram of
sodium chloride, 0.2 gram of calcium chloride and 0.1 gram of magnesium
chloride per 10 cc. of sample.
The data obtained, expressed in grams per 10 cc. of brine, are contained
in Table 1.
TABLE 1.
Bromine obtained by cooperators in synthetic sample of brine.
Ww. E. SHAEFER * DEARBORN J. G. FAIRCHILD f C. H. BADGER * J. W. SALE
CHEMICAL Co. ¢
0.0740 0.0717 0.0742 0.0756 0.0789
0.0787 0.0713 0.0748 0.0765 0.0768
0.0758 (OU Ale MN ood 0.0761 0.0782
0.0781 OLO7Eiig* ieee teers OF0765.e> |) eset
OcOT46i im Madi ay coe sr cece WRF) Aci Sepee sch eae eee teiete
OE O77 Ai ee Acdece Melbtomoac. ih. 9 dodsoc
ONOTBS ®rst) we eres ee coke on nen | oe
* Bureau of Chemistry, Washington, D. C.
t Chicago, Il
t Geological Survey, Washington, D. C.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 381.
1921] SALE: REPORT ON WATER 31
IAVEra Red: hepicins ses leis. eieioaeioes 0.0755
HW Iolani con OeIG Gros ot Se nee 0.0800
1 Drake) Sa eIbigto I OOO Ga Dae a OOS ES 5.6 per cent.
Maxamum errors. a=) 3 0 -/isislaei-ve 10.9 per cent.
Minimum (errors seis assess eles 1.4 per cent.
These results are not so satisfactory as the authors of the method
obtained. In fourteen tests the authors recovered 98.2 per cent of the
theoretical amount of bromine, whereas our cooperative work indicates
that about 95 per cent of the bromine present is recovered.
The method suggests that about 1 hour is sufficient time to aspirate
the second time, but it was found that this time should be increased to
at least 2 hours. This modification, however, did not result in the re-
covery of all of the bromine present in the sample.
While it is appreciated that the determination of bromine in mineral
waters and brines is beset with difficulties, and that as good results can
be obtained by this method as by any in the literature, yet the referee
hesitates to recommend it for adoption by the association in view of
the results obtained, and especially since the methods for the mineral
analysis of water and brine heretofore adopted by the association are
capable of giving very accurate results. The low results obtained are
probably inherent in the method, and the referee doubts if they can be
corrected by modifications. It is recommended, therefore, that instead
of adopting this method at the present time, the following statement be
inserted in the methods of analysis:
“*A volumetric method for the determination of bromine in the presence
of chlorine and iodine has been published!. Cooperative work indicates that
this is probably the best method for bromine which has been published,
but the results obtained show that only about 95 per cent of the bromine
present is recovered, when 80 mg. of bromine are contained in the portion
of the sample used for analysis. The method is satisfactory in the absence
of iodine, as shown by the cooperative work on water in 1919.”’
Another method for bromine?, which depends upon the oxidation of
bromine with chlorine water, subsequent distillation of the bromine
formed, and finally titration with standard thiosulfate solution, was
tested by W. E. Shaefer at the request of the referee. The results obtained
on the sample of synthetic brine used in this cooperative work were
inconclusive. The determination of bromine by this method is rapid,
and the referee hopes to do some additional work on it.
A method for the estimation of nitrates in water? was recently pub-
lished. The official method‘ of this association involves the removal of
chlorine from the sample by means of standard silver sulfate and sub-
Se ae
3 Analyst., 1919, 44: 281.
4 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 23.
32 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
sequent treatment of the dried residue with phenoldisulfonic acid re-
agent. The new method provides for the addition of a diluted phenol-
disulfonic acid reagent to the sample before evaporation, which is said
to obviate the necessity of the removal of chlorine, thus appreciably
reducing manipulation. In the routine work in the referee’s laboratory,
69 samples of water were examined, both by the official method and by
the new method for nitrate. The two methods gave results which checked
in only four cases, the new method giving higher results in 42 cases and
lower results in 23 cases, the discrepancy being very large in most
instances. A brown coloration was observed frequently on samples run
by the new method. This made the colorimetric comparison very un-
satisfactory. Under the circumstances, it is believed we are not justified
in doing any further work on the new method for nitrate until it has been
modified by individual workers.
Except to recommend a continuation of the work on bromine, the
referee will not limit the activities of his successor.
REPORT ON TANNING MATERIALS AND LEATHER.
By F. P. Verrcu (Bureau of Chemistry, Washington, D. C.), Referee.
Your referee has no formal report to make. No cooperative work
could be undertaken. Work has been done, however, on a problem
which is of the greatest importance in the analysis of tanning materials
and of leather, and in which the association may also be interested
because it is equally important in all analytical work, especially in the
determination of moisture or of total solid matter.
It has long been known to analysts that the determination of moisture
in finely ground fibrous or fluid materials is difficult and that rarely two
analysts, operating at different places or the same analyst operating
under different conditions, can get closely agreeing results.
For several years following the experience of the writer in the effect
of atmospheric humidity on the physical testing of paper, leather, etc.,
he has been of the opinion that the relative humidity of the air has a
great deal to do with the determination of moisture and of total solids,
and experiments thus far conducted, while they can not be regarded as
finally conclusive, are indicative that the higher the atmospheric humidity
at the time a determination is made, the lower the apparent moisture
or the higher the total solids determination will be. If, however, the
relative humidity of the air remains constant, closely agreeing results
can be obtained repeatedly and, if there are losses, they are progressive
and the percentage of moisture or total solids does not fluctuate under
these conditions as it does when the material is first dried at low humid-
1921 GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 33
ity and then at high humidity, and again at low humidity, etc. In
other words, the percentage of moisture or of solids in a material fluctu-
ates just as the relative atmospheric humidity existing at the time the
moisture determination is made fluctuates and this fluctuation exists to
a lesser degree even when the materials are dried at reduced pressure.
It is not necessary to point out, of course, how important this fact,
if it is a fact, is in all lines of analytical work. It certainly accounts, in
part, at least, for many of the discrepancies which have heretofore been
obtained in the work on the determination of moisture and of solids.
It is of the highest importance in the analysis of tanning extracts and
-in the analysis of leather, where a difference of 2 mg. in the weight of
the dried material will make an error of 0.3 per cent on a solid extract.
REPORT ON INSECTICIDES AND FUNGICIDES.
By J. J. T. Granam (Bureau of Chemistry, Washington, D. C.), Referee.
The cooperative work included a study of methods for the determina-
tion of total arsenic and arsenious oxide in Paris green; for the deter-
mination of total arsenic, arsenious oxide, water-soluble arsenic and cal-
cium oxide in calcium arsenate containing calcium arsenite; for the de-
termination of arsenious oxide, water-soluble arsenic and zinc oxide in
zine arsenite; for the determination of total arsenic in London purple;
and for the determination of lead oxide, zinc oxide and copper in Bor-
deaux-lead arsenate-zinc arsenite.
Some of these methods were tested last year, while others are being
considered for the first time this year.
Thirty laboratories were invited to cooperate in the work. Of these,
six promised to assist in part of the work, and results have been received
from ten analysts in three different laboratories.
The following methods were tested:
PARIS GREEN.
TOTAL ARSENIC.
REAGENTS.
(a) Starch indicator —Prepare as directed under Paris green’.
(b) Standard arsenious oride solution.—Prepare as directed under Paris green’.
(C) Standard iodine solution—Prepare as directed under Paris green’.
(d) Standard potassium bromate solution—Dissolve 1.688 grams of pure potassium
bromate in water and dilute to 1 liter. One ce. of this solution is approximately equal
to 0.00300 gram of arsenious oxide. To standardize, transfer 25 cc. aliquots of the
standard arsenious oxide solution to 500 cc. Erlenmeyer flasks, add 15 cc. of hydro -
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 53.
34 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
chloric acid (sp. gr. 1.19), dilute to 100 cc., heat to 90°C. and titrate with the bromate
solution, using methyl orange as indicator. The indicator should not be added until
near the end of the titration, and the flask should be rotated continuously in order to
avoid any local excess of the bromate solution. The end point is shown by a change
from red to colorless, and the bromate should be added very cautiously when approach-
ing the end of the titration.
(e@) Standard potassium iodate solution —Dissolve 3.244 grams of pure potassium
iodate in water and dilute to 1 liter. One cc. of this solution is approximately equal
to 0.00300 gram of arsenious oxide. To standardize, transfer 25 cc. aliquots of the
standard arsenious oxide solution to 250-500 cc. glass-stoppered bottles, add 55 cc. of
hydrochloric acid (sp. gr. 1.19), and dilute to 100 cc. Add 5 cc. of chloroform, and
titrate with the iodate solution until the iodine disappears from the chloroform when
the mixture is thoroughly shaken.
DETERMINATION.
Official Distillation Method.
Proceed as directed under Paris green’.
Bromate Method?.
Proceed as directed under the official distillation method, using an amount of the
sample equal to the arsenious oxide equivalent of 250 cc. of the standard potassium
bromate solution, until the distillate is made to volume in a liter graduated flask.
(1) Transfer 200 cc. aliquots of the distillate to 500 cc. Erlenmeyer flasks, heat to
90°C. and titrate with the standard potassium bromate solution, using methyl orange
as indicator. The indicator should not be added until near the end of the titration,
and the solution should be rotated continuously in order to avoid any local excess of
the bromate solution.
(2) Proceed as in (1) with the exception that the titration is made without heating
the solution.
The number of cc. of standard bromate solution used, multiplied by 2, represents
the per cent of total arsenic in the sample, expressed as arsenious oxide.
Todate Method.
Proceed as directed under the official distillation method, using an amount of the
sample equal to the arsenious oxide equivalent of 250 cc. of the standard potassium
iodate solution, except that the distillate is made to a volume of 500 cc. Transfer
100 cc. aliquots of the distillate to 250-500 cc. glass-stoppered bottles, add 5 cc. of
chloroform and 10 cc. of hydrochloric acid (sp. gr. 1.19), and titrate with the
standard iodate solution until the iodine disappears from the chloroform when the
mixture is thoroughly shaken*. The number of cc. of standard iodate solution used,
multiplied by 2, represents the per cent of total arsenic in the sample, expressed as
arsenious oxide.
ARSENIOUS OXIDE.
DETERMINATION.
C. C. Hedges’ Method Modified.
Proceed as directed under Paris green‘,
Bromate Method.
Weigh an amount of the sample equal to the arsenious oxide equivalent of 250
cc. of the standard bromate solution, wash into a 250 cc. volumetric flask with 100 ce.
of hydrochloric acid (1 to 3), heating to a maximum of 90° C. if necessary to get the
sample completely dissolved. Cool, and make to volume.
(1) Transfer a 50 cc. aliquot to a 500 cc. Erlenmeyer flask, add 10 ec. of hydrochloric
acid (sp. gr. 1.19), heat to 90°C. and titrate with the standard bromate solution as
directed under total arsenic.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 54.
* Z. anal. Chem., 1893, 32: 415; J. prakt. Chem., 1915, ‘91: 133.
3 J. Am. Chem. Soc., 1903, 25: 756; J. Ind. Eng. Chem., 1918, 10: 291.
* Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, "55.
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 35
(2) Proceed as in (1) with the exception that the titration is made without heating
the solution.
The number of cc. of the bromate solution used, multiplied by 2, represents the
per cent of arsenious oxide in the sample.
Todate Method.
Weigh an amount of the sample equal to the arsenious oxide equivalent of 250 ce. of
the standard iodate solution, wash into a 250 cc. volumetric flask with 100 cc. of
hydrochloric acid (1 to 3), heating to a maximum of 90° C. if necessary to get the sample
completely dissolved. Cool, and make to volume. Transfer a 50 cc. aliquot to a
250-500 ce. glass-stoppered bottle, add 50 cc. of hydrochloric acid (sp. gr. 1.19), and
titrate with the standard iodate solution as directed under total arsenic. The number
of cc. of iodate solution used, multiplied by 2, represents the per cent of arsenious
_ oxide in the sample.
TaBLe 1.
Cooperative results on Paris green.
ANALYST BE eer en AB ARSENIOUS OXIDE
ARSENIOUS OXIDE
gz] 3 g ||| 2 2z
222)322|323) £2 | £22 |232|/324| 23
BSS(2ssloss 3s SSsiHosjosS| 33
S) 2 ale papel eae ssl ge] gal “s
per cent | per cent | per cent | per cent\| per cent | per cent | per cent | per cent
F. L. Hart, Bureau of| 54.60 | 54.43 | 54.43 | 54.46 || .... | 54.47 | 54.43 | 54.56
Chemistry, Washington,| 54.69 | 54.47 | 54.43 | 54.46 || .... | 54.49 | 54.43 54.56
1B Ga cycciil (Late Ieicicucaa | (De 2) Se | hae eee SoS
LS ERT Dee pa Oded BOSE 54.65 | 54.45 | 54.43 | 54.48 || .... | 54.48 | 54.43 | 54.56
54.25 | 54.35 | 54.35 | 54.30 || 54.21 | 54.35 | 54.44 | 54.60
J. J. T. Graham 54.34 | 54.44 | 54.35 | 54.30 || 54.11 | 54.35 | 54.35 | 54.60
.... | 54.35 | 54.35] .... || 54.25 | 54.35 | 54.54 | 54.50
INVELARC wierete) aia.catxis' este): 54.30 | 54.38 | 54.35 | 54.30 || 54.19 | 54.85 | 54.44 | 54.57
General Average....... 54.47 | 54.41 | 54.38 | 54.41 || 54.19 | 54.40 | 54.44 | 54.56
COMMENTS BY ANALYST.
J. J. T. Graham.—All of the methods checked very closely. The reaction is slow in
the cold bromate method and the titrating solution must be added very slowly when
the arsenic solution is nearly all oxidized, otherwise the end point may be passed.
The hot bromate method is very satisfactory. The iedate method gives accurate
results, but the manipulation is not so smooth and easy as in the bromate method.
DISCUSSION.
The bromate and iodate methods for total arsenic both gave excellent results and
checked the official distillation method quite closely. These methods also proved
satisfactory when applied to the determination of arsenious oxide. A full discussion
of these methods will be given under calcium arsenate.
36 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
CALCIUM ARSENATE.
The following methods were tested:
TOTAL ARSENIC.
REAGENTS.
(a) Starch indicator.—Prepare as directed under Paris green?.
(b) Standard arsenious oxide solution—Prepare as directed under Paris green’.
To convert arsenious oxide to arsenic oxide use the factor 1.16168.
(C) Standard iodine solution.—Prepare as directed under Paris green’.
(d) Standard potassium bromate solution—Dissolve 1.688 grams of pure potassium
bromate in water, dilute to 1 liter, and standardize as directed under Paris green,
page 33.
(€) Standard potassium iodate solution—Dissolve 3.244 grams of pure potassium
jiodate in water, dilute to 1 liter, and standardize as directed under Paris green, page 34.
DETERMINATION.
Official Distillation Method.
Proceed as directed under Paris green*, using an amount of the sample equal to the
arsenic oxide equivalent of 500 cc. of the standard iodine solution and titrating 200
ec. of the distillate. The number of cc. of standard iodine solution used represents
directly the total per cent of arsenic in the sample, expressed as arsenic oxide.
Bromate Method‘.
Proceed as directed under the official distillation method until the distillate is
made to volume ina liter graduated flask, using an amount of the sample equal to the
arsenic oxide equivalent of 500 cc. of the standard potassium bromate solution.
(1) Transfer 200 cc. aliquots of the distillate to 500 cc. Erlenmeyer flasks, heat to
90° C. and titrate with the standard potassium bromate solution, using methyl orange
as indicator. The indicator should not be added until near the end of the titration,
and the solution should be rotated continuously in order to avoid any local excess of
the bromate solution.
(2) Proceed as in (1) with the exception that the titration is made without heating
the solution.
The number of cc. of the standard bromate solution used, represents directly the
total per cent of arsenic in the sample expressed as arsenic oxide.
Iodate Method.
Proceed as directed under the official distillation method, using an amount of the
sample equal to the arsenic oxide equivalent of 500 cc. of the standard potassium iodate
solution, with the exception that the distillate is made to a volume of 500 ce.
Transfer 100 cc. aliquots of the distillate to 250-500 cc. glass-stoppered bottles, add
5 ce. of chloroform and 10 cc. of hydrochloric acid (sp.gr. 1.19), and titrate with the
standard iodate solution until the iodine disappears from the chloroform when the
mixture is thoroughly shaken‘. The number of cc. of standard iodate solution used,
represents directly the total per cent of arsenic in the sample, expressed as arsenic oxide.
ARSENIOUS OXIDE,
DETERMINATION.
Bromate Method.
Weigh an amount of the sample equal to the arsenious oxide equivalent of 300
cc. of the standard potassium bromate solution. Transfer to a 500 cc. Erlenmeyer
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 53.
2 Tbid., 54.
+ Z. anal. Chem., 1893, 32: 415; J. prakt. Chem., 1915, 91: 133.
«J. Am. Chem. Soc., 1903, 25: 756; J. Ind. Eng. Chem., 1918, 10: 291.
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES Be
flask, dissolve in 25 cc. of hydrochloric acid (sp. gr. 1.19) and dilute to 100 cc. Heat
to 90° C. and titrate with standard bromate solution, using methyl orange as indi-
cator. The number of cc. of bromate solution used, divided by 3, gives the per cent
of arsenious oxide in the sample.
Iodate Method.
Weigh an amount of the sample equal to the arsenious oxide equivalent of 300 cc. of
the standard potassium iodate solution. Transfer to a 300-500 cc. glass-stoppered
bottle and dissolve in 30 cc. of hydrochloric acid (sp. gr. 1.19), and 20 cc. of water.
Add 5 cc. of chloroform and titrate with standard iodate solution, as directed under
Paris green. The number of cc. of standard iodate solution used, divided by 3,
gives the per cent of arsenious oxide in the sample.
Tentative Method for Arsenious Oxide in Lead Arsenate.
Proceed as directed under lead arsenate!.
WATER-SOLUBLE ARSENIC.
Proceed as directed under lead arsenate!.
CALCIUM OXIDE.
Dissolve 2.0 grams of the sample in 80 cc. of acetic acid (1 to 3), transfer to a 200
ec. volumetric flask and make to volume. Filter through a dry filter and transfer a
50 cc. aliquot to a beaker; dilute to 200 cc., heat to boiling and precipitate the calcium
with ammonium oxalate. Allow the beaker to stand for 3 hours on the steam bath,
filter and wash with hot water. Dissolve the precipitate in dilute sulfuric acid and
titrate with permanganate, or ignite and weigh as oxide.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 59.
38 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
TABLE
Cooperative results on caleium
TOTAL ARSENIC CALCULATED AS ARSENIC OXIDE
ANALYST
Official Hot Cold
Distillation Bromate Bromate Todate
Method Method Method Method
per cent per cent per cent per cent
R. H. Robinson, Agricultural 44.98 44.95 44.99 44.98
Experiment Station, Cor- 44.98 45.02 44.97 44.99
vallis, Ore. 44.98 44.99 44.97 44.99
Average tacriceacnr sana 44.98 44.99 44.98 44.99
F. L. Hart 44.48 44.61 44.61 44.68
44.58 44.72 44:61 97 i) ee
AV ERage snc ois casi) stere se eueres 44.53 44.67 44.68
M. H. Goodman, Bureau of 44.90 44.97 44.77
Chemistry, Washington,
Dac: 44.69 44.97 44.92
Average). ti iageas, 2 ae 44.80 44.97 44.85
C. F. Sheffield, Agricultural 45.22 44.84 45.27
College, Miss. 45.15 44.90 45.27
Aree 45.02 she) svete
Average’. abyss. Sasreniae se 45.19 44.92 45.27
J. J. T. Graham 44.66 44.60 44.67
44.66 44.60 44.67
44.72 44.65) =). 44:65) «luis teeter
INN OVER ici -c!cvojeraiststs: vise ats 44.68 44.62 44.67
H.D. Young, Bureau of Chem-
istry, Washington, D.C. 0 || citerecvn i) easracverst lle eciereieh ell eee
AVGrageiscicprssibicjsieivcsc acl CD ee! TR ee eel | (eee
C. M. Smith, Bureau of Chem-
istry; Washington, D:'G@. | nace. 2)|) essen GIP erie ean eee
AV erage. ghee! Aiea ee ee ee eae ico lige eee
General Average.......... 44.83 44.83 44.92
COMMENTS BY ANALYSTS.
R. H. Robinson —Excellent checks were obtained by all methods for both the total
arsenic oxide and the total arsenious oxide of the calcium arsenate containing calcium
arsenite. No difficulty was experienced with the iodate method. In the bromate
method it was observed that when titrating without heating the solution, the standard
bromate solution should be added slowly near the end of the titration in order to per-
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 39
2.
arsenate containing calcium arsenite.
ARSENIOUS OXIDE CALCIUM OXIDE
WATER-SOLUBLE
Hot Tentative Tedate reas : P
eeamiats neat Besenate Method Titrated Ignited
per cent per cent per cent per cent per cent per cent
4.78 4.79 4.78 0.31 44.50
4.80 4.79 4.78 0.31 44.45 SOKO
4.79 nic 4.78 0.31 44.44 ne
4.79 4.79 4.78 0.31 44.46 eich
4.82 or 4.86 0.42 43.84 45.08
4.85 Se 4.90 0.45 43.94 45.12
4.84 geicue 4.88 0.44 43.89 45.10
4.73 be 4.68 0.37 tere
4.73 Snoe 4.70 0.35
4.73 Bsus 4.69 0.36
4.83
4.83
4.83
4.83 4.92 0.37 43.93 43.96
4.82 4.96 0.37 44.00 44.24
4.82 Pea 0.39 44.00 44.96
4.82 4.94 0.38 43.98 44.39
44.08
44.08
44.08
44.00 44.45
44.02 44.30
43.98 44.40
aveke 44.00 44.38
4.81 4.87 037° 44.10 44.56
mit reaction and allow the methyl orange to bleach; otherwise, slightly higher results
may be obtained.
In the determination of water-soluble arsenic, good triplicate results were obtained
at 32° C. if controlled in a similar manner.
C. M. Smith—When the acetic acid solutions of the sample were heated before
precipitating the calcium with ammonium oxalate, a slight cloudiness developed,
40 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
which may mean that something not an oxalate precipitated, giving higher results by
ignition than by titration.
F. L. Hart—I checked the bromate titration for total arsenic against both the
official iodine titration and the Gooch-Browning method on about 50 samples, and ob-
tained very good checks. Cold titration works as well as hot, provided the end point
is approached more slowly.
In regard to the precipitation of calcium in acetic acid, without previous removal
of the arsenic, it seems probable that aluminium comes down as an arsenate along with
the calcium oxalate. I obtained appreciable amounts of both aluminium and arsenic
in the residues from ignitions of the calcium oxalate. This, of course, would not
interfere if the oxalate were titrated with potassium permanganate.
DISCUSSION.
The bromate and iodate methods for total arsenic gave results that checked very
closely the official distillation method. While there is a small variation in the analyses
between the different cooperators, the results by individual analysts run uniform for
the three methods. Such variation as was obtained can be attributed to differences
in standardization of the titrating solutions. Jannasch and Seidel’ found that the
end point in the bromate method was most rapid in solutions whose acidity was between
land 3N. The referee has confirmed their statement and finds that the best results
are obtained in solutions of approximately 2N acidity.
Nissenson and Siedler? in using this method for antimony found that titrations in
hot and cold solutions lead to the same results, the hot titrations, however, giving
a sharper end point. The work of the referee and a number of the cooperating analysts
has shown this to be true also when applied to the determination of arsenic. During
titrations in the cold solution the bromate must be added slowly toward the end of
the titration in order to allow complete reaction or the results obtained will be slightly
high.
A good procedure in the application of the bromate method to routine analysis is to
have a standard arsenious oxide solution of exactly the same strength as the bromate
solution. In this case the titration is carried on until the red color is destroyed, then
a few tenths of a cc. of the arsenious oxide solution and more methyl orange are added
and the titration carefully completed. The total titration, minus the amount of added
arsenious oxide solution, gives the titration due to the arsenic in the sample.
The results for arsenious oxide by all of the methods are good. When the tentative
lead arsenate method is applied to the determination of arsenious oxide in calcium
arsenate, considerable attention must be given to making the solution, as superheating
occurs, due to the presence of the bulky precipitate of calcium sulfate, which may cause
violent bumping.
The method tested for water-soluble arsenic is the one already adopted for water-
soluble arsenic in a number of arsenicals, and the results on calcium arsenate are good.
The method for calcium oxide gave good checks when the precipitate was titrated,
but the results were high when ignited and weighed. F.L. Hart found aluminium and
arsenic in the residues after ignition of the calcium oxalate precipitates, and it is also
possible that the precipitate may be contaminated with silica. Hart also determined
the calcium oxide in this sample by precipitation in ammoniacal solution, after removal
of the arsenic, iron and aluminium. His analysis showed 44.07 per cent by titration
and 43.96 per cent by ignition.
To eliminate this contamination of the calcium oxalate precipitate, the method has
been modified as follows:
1J. prakt. Chem., 1915, 91: 133.
2 Chem. Zlg., 1903, 27: 749.
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 41
Weigh 2 grams of the sample, transfer to a beaker, add 5 cc. of hydrobromic acid
(sp. gr. 1.31) and 15 cc. of hydrochloric acid (sp. gr. 1.19) and evaporate to dryness to
remove arsenic; repeat the treatment; then add 20 cc. of hydrochloric acid and again
evaporate to dryness. Take up with water and a little hydrochloric acid, filter into a
200 cc. volumetric flask, and make to volume. Transfer a 50 cc. aliquot to a beaker,
add 10 cc. of hydrochloric acid and make slightly alkaline with ammonia, using methyl
red as indicator. Heat to boiling and filter. Dissolve the precipitate in a little hydro-
chloric acid, reprecipitate and filter through the same paper. To the combined filtrates
and washings add 20 ce. of acetic acid (1 to 3) and adjust the volume to about 200 cc.;
heat to boiling, add ammonium oxalate slowly from a buret and allow to stand for 3
hours on a steam bath. Filter, wash with hot water, ignite and weigh as calcium
oxide; or dissolve the precipitate in dilute sulfuric acid, heat and titrate with potassium
permanganate.
Analysis of this sample by the referee, using the modified method, gave 43.93 per
- cent of calcium oxide by titration and 43.91 per cent by ignition. These results agree
very closely with those obtained volumetrically by the cooperators and show that
the method as tested this year gives accurate results when the calcium oxalate is titrated
with permanganate. This method is much shorter than the modification outlined
above, and the referee recommends that it be adopted as a tentative method, for volu-
metric work only.
The referee submits the following table of results comparing the hot bromate method
with the official distillation method for total arsenic under routine laboratory condi-
tions. After the distillations were completed, one titration was made by the official
iodine method and the other by the bromate method.
TABLE 3.
Comparison of the bromate with the-official distillation method for total arsenic.
(Analyst, F. L. Hart.)
MATERIAL ANALYZED BROMATE ee oar VARIATION
per cent per cent per cent
Magnesium arsenate 31.31 31.45 —.14
Magnesium arsenate 31.86 31.96 —.10
Magnesium arsenate 31.28 31.20 +.08
Calcium arsenate 47.61 47.71 —.10
Calcium arsenate 41.63 41.76 —.13
Calcium arsenate 46.68 46.57 +.11
Calcium arsenate 41.95 41.89 +.06
Calcium arsenate 39.67 39.80 —.13
Calcium arsenate 16.34 16.34 0.00
Calcium arsenate 18.17 18.00 +.17
Calcium arsenate 38.09 38.07 +.02
Calcium arsenate 39.70 39.60 +.10
Calcium arsenate 45.83 45.79 +.04
Calcium arsenate 42.33 42.47 —.14
Calcium arsenate 40.25 ~ 40.24 +.01
Calcium arsenate 38.42 38.28 +.14
Calcium arsenate 34.04 34.12 —.08
Calcium arsenate 40.25 40.24 +.01
Calcium arsenate 40.17 40.11 +.06
Calcium arsenate 41.86 41.87 —.01
Calcium arsenate 40.81 40.70 +.11
Calcium arsenate 40.81 40.89 —.08
Lead arsenate 30.67 30.65 +.02
Calcium-lead arsenate 16.10 16.14 —.04
42 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
BORDEAUX-LEAD ARSENATE-ZINC ARSENITE.
To test the methods for lead oxide, copper and zinc oxide, a sample
was prepared by thoroughly mixing 200 grams of Bordeaux mixture,
made from commercial copper sulfate and lime, with 100 grams of com-
mercial lead arsenate and 100 grams of commercial zinc arsenite.
The Bordeaux, when analyzed by the official electrolytic method,
showed a copper content of 16.18 per cent; the lead arsenate was shown
to contain 63.67 per cent of lead oxide by the official sulfate method;
while the zinc arsenite contained 57.28 per cent of zinc oxide by the
phosphate method.
The mixture submitted for cooperative work should contain, there-
fore, 8.09 per cent of copper; 15.92 per cent of lead oxide; and 14.32 per
cent of zinc oxide.
The directions that were sent out for the determination of these con-
stituents are as follows:
GENERAL PROCEDURE FOR THE ANALYSIS OF A PRODUCT CONTAINING AR-
SENIC, ANTIMONY, LEAD, COPPER, ZINC, IRON, CALCIUM,
MAGNESIUM, ETC.
(Applicable to such preparations as Bordeaux-lead arsenate; Bor-
deaux-zinc arsenite; Bordeaux-Paris green; Bordeaux-calcium arsenate;
etc.)
LEAD OXIDE
Weigh 1 gram of the dry, powdered sample, transfer to a beaker, add 5 cc. of hydro-
bromic acid (sp. gr. 1.31) and 15 ce. of hydrochloric acid (sp. gr. 1.19) and evaporate
to dryness to remove arsenic; repeat the treatment; then add 20 ce. of hydrochloric
acid (sp. gr. 1.19) and again evaporate to dryness. Dissolve the residue by heating
to boiling in 25 cc. of 2N hydrochloric acid, filter immediately to remove silica, and
wash with hot water to a volume of 125 ce. Care must be taken to see that all lead
chloride is in solution before filtering. Treat with hydrogen sulfide until precipitation
is complete. Filter and wash the precipitate thoroughly with 0.5N hydrochloric acid
saturated with hydrogen sulfide. Save the filtrate and washings for the determina-
tion of zinc. Transfer the filter paper containing the sulfides of lead and copper to a
400 cc. Pyrex beaker and completely oxidize all organic matter by heating with a
few cc. of sulfuric acid, together with a little fuming nitric acid; then completely remove
all nitric acid by heating on a hot plate to copious evolution of the white fumes of sul-
furic acid, cool, add 2-8 ce. of water and again heat to fuming. Cool and determine
the lead as sulfate as directed for lead arsenate!, beginning with “Cool, add 50 cc. of
water and about 100 ce. of 95% alcohol”. The alcoholic copper solution should not
stand more than 24 hours before filtering, as the solution may creep up the sides of
the beaker and deposit crystals of copper sulfate which are very difficult to redissolve
in the acid alcohol. From the weight of lead sulfate calculate the amount of lead
oxide present, using the factor 0.73600.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 58.
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 43
COPPER.
Evaporate the filtrate and washings from the lead sulfate precipitate to fuming,
add a few cc. of fuming nitric acid to destroy organic matter, and continue the evapora-
tion until about 3 cc. of concentrated sulfuric acid remain. Determine the copper
by Low’s titration method as directed under Bordeaux mixture!, or by electrolysis
as follows:
Take up the sulfuric acid solution with water, add 1 cc. of concentrated nitric acid,
and filter if necessary. Make the volume to about 150 cc. and electrolyze as usual.
ZINC OXIDE.
REAGENT.
- Mercury-thiocyanate solution——Dissolve 27 grams of mercuric chloride and 39 grams
of potassium thiocyanate in 1 liter of water. In lieu of the potassium thiocyanate,
30 grams of ammonium thiocyanate may be used’.
DETERMINATION.
Carefully concentrate the filtrate and washings from the sulfide precipitation by
gentle boiling to about 50 cc. or until all hydrogen sulfide is expelled. Cool, dilute to
100 cc., neutralize with ammonia and add 5 cc. of hydrochloric acid (1 to 1) to each
100 ec. of solution. Add 25 cc. of the mercury-thiocyanate reagent per 100 cc. of
solution, and stir vigorously until the zinc is precipitated. Allow to stand for at least
1 hour with occasional stirring, filter through a tared Gooch crucible, wash with water
containing 20 cc. of the mercury-thiocyanate reagent per liter, dry at 105° C. and weigh.
From this weight calculate the zinc oxide, using the factor 0.16331.
NotEe.—Some iron is generally present and during the zinc determination it should be
in the ferrous condition. In making the sulfide precipitation the hydrogen
sulfide should be passed into the solution for a sufficient time to reduce the iron, in
addition to precipitating the copper and lead. The zinc-mercury-thiocyanate pre-
cipitate normally is white and it should not contain occluded ferric thiocyanate suf-
ficient to give it more than a faint pink color.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 62.
2 Trans. Am. Inst. Met., 1914, 8: 146; J. Am. Chem. Soc., 1918, 40: 1036.
44 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TABLE 4.
Cooperative results on Bordeauz-lead arsenate-zine arsenile.
ANALYST ZINC OXIDE LEAD OXIDE COPPER
per cent per cent per cent
C. B. Stone, Bureau of Chemistry, Washing- 13.94 16.03 7.90
ton, D.C, 14.10 16.03 7.88
13.94 15.97 7.92
13.84 16.21 7.88
V4:00"° OO) SSS Feces
IAVELAGE sa semnetelepia ctesisietaresteeleen tistteneetenr 13.96 16.06 7.90*
F. L. Hart 14.00 15.92 8.04
14.04 VG12 ita. | eis
INN,CT ARCs. ays ois where sisieinioss esse ayevoie's wisteseuetareie 14.02 16.02 8.047
14.05 16.04 8.00
14.03 16.06 8.04
J. J. T. Graham 13.97 16.16 8.00
14.08 16.00 8.04
14.04 16067" "|" eee
Retake 16.10 aleftberate
LARS CRO ATER Oe CaO ee SO CUO Or 14.03 16.07 8.02*
13.94 16.05 8.02
H. D. Young 13.93 16.18 8.00
INVELAR EC. rete Seis iefs steve creivetcate eres stesssierete 13.94 16.12 8.01.f
General average: 5..c.cceeettertas 13.99 16.07 7.97
Galcolated valuéjcsc.J.0.-1-- cee oe 14.32 15.92 8.09
* Determine i electrolytically. "
Determined by Precmang the copper as sulfide, igniting and weighing as copper oxide.
Determined by ae titration method.
DISCUSSION.
The methods for lead oxide and copper are essentially the same as those sent out by
the previous referee, while the mercury-thiocyanate method for zinc oxide was tested
this year for the first time. The method of preparing the solution has been amended
to eliminate any silica that may be present and cause the results for lead oxide to be
slightly high. (With this modification care must be taken to see that the lead chloride
is all dissolved in the 2N hydrochloric acid before filtering from the silica, or a loss
may occur at this point. When large amounts of lead oxide are present it may be
necessary to use twice the quantity of 2N acid, and dilute accordingly before pre-
cipitating the lead with hydrogen sulfide.) The condition of acidity during the hydro-
gen sulfide precipitation should be kept within narrow limits, as stated by the referee
in 1916', in order to insure complete precipitation of the lead without contamination
with zine sulfide. The results obtained by the different analysts on this sample agree
1 J. Assoc. Official Agr. Chemists, 1920, 3: 338,
1921) GRAHAM REPORT ON INSECTICIDES AND FUNGICIDES 45
yery well, and show that the methods give excellent results when closely followed.
In the zinc determination it is important that the solution be allowed to cool to room
temperature before adding the mercury-thiocyanate reagent, and the precipitate
should not be washed more than four or five times.
LONDON PURPLE.
The methods tested are as follows:
TOTAL ARSENIC.
REAGENTS.
(a) Standard solutions.—As given under Paris green’.
(b) Zine oxide-sodium carbonate mizture.—Four parts of zinc oxide and one part of
dry sodium carbonate.
(C) Blood charcoal.
DETERMINATION.
Official Iodine Method.
Determine as directed under London purple?.
Zine Oxide-Sodium Carbonate Method.
Weigh an amount of the sample equal to the arsenious oxide equivalent of 250 cc.
of the standard iodine solution. Mix the sample thoroughly with several times its
weight of the zinc oxide-sodium carbonate mixture in a shallow porcelain crucible,
and cover with a layer of the same mixture. Place the crucible, uncovered, ina
mufile; heat, gently at first and finally for about 15 minutes at full heat. The mass will
not sinter. Cool, transfer to a distillation flask and proceed according to the official
distillation method for total arsenic in Paris green.
Adsorption Method.
Proceed as directed under the official iodine method for total arsenic in Paris green,
except that 3-4 grams of blood charcoal are added to the flask before beginning the
distillation.
Official Distillation Method.
Determine as directed under Paris green’.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 53.
2 [bid., 56.
3 [bid., 54.
46 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TABLE 5.
Cooperative results on London purple.
(Total arsenic calculated as arsenious oxide.)
E OFFICIAL OFFICIAL ADSORPTION ZINC OXIDE-
ANALYST IODINE DISTILLATION METHOD SODIUM CARBON-
METHOD METHOD ATE METHOD
i per cent per cent per cent per cent
C. B. Stone 29.64 29.81 29.69 29.77
29.64 29.81 29.80 29.77
CABS 29.70 Be ors 29.77
AWeragelic.c..nn ve seer 29.64 29.77 29.75 29.77
29.44 29A4P ee eigee 29.39
J. K. Dickerson, Bureau of 29.36 294A ler 2 torah 29.39
Chemistry, Washington, DOVAA A” Aer cre lle wccateretees all Nae eete ee
DAEs PAD as aie ee es cen hI acon ||) Potyasa> =
AVEragzen 6.<:ca mui amncvse 29.44 DOA ee oascesaye 29.39
R. F. Russ, Bureau of Chem-| ....... 29.66 29.69 29.84
istry, Washington: D: (Cony... 29.66 29.69 29.84
soeepostedl| Hiieteo atin ll dee SSB SEG 29.84
IAN EQABO' oo lstaislatyeie serie. Wess aavect 29.66 29.69 29.84
General Average.......... 29.51 29.65 29.72 29.70
DISCUSSION.
The results submitted by the analysts show good agreement by all of the methods.
There has been some objection to the use of the official distillation method for Lon-
don purple on the ground that dyes are carried over into the distillate, coloring it some-
what and interfering with the titration. The referee has never experienced any diffi-
culty with this method. While the results by the blood charcoal adsorption method
agree very closely with those by the other methods, the referee does not feel that this
method should be made official. He has found considerable variation in the results
for total arsenic on the same London purple when different lots of blood charcoal were
used, and it is quite possible that some arsenic may be held in the distillation flask by
the charcoal.
ZINC ARSENITE.
The methods tested are as follows:
ZINC OXIDE.
REAGENT.
Dissolve 27.0 grams of mercuric chloride and 39 grams of potassium thiocyanate in
1 liter of water. In lieu of the potassium thiocyanate, 30 grams of ammonium thio-
cyanate may be used.
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 47
DETERMINATION.
Mercury-Thiocyanate Method}.
Weigh 2.0 grams of the sample and transfer to a beaker. Dissolve in 20 cc. of
concentrated hydrochloric acid, wash into a 200 cc. volumetric flask, and dilute to
volume. Thoroughly mix the solution and filter through a dry filter. Transfer a 25 cc.
aliquot to a beaker and add 5 cc. of concentrated hydro chloricacid. If there is much
iron present it should be reduced at this point by adding a little sodium bisulfite and
heating on the steam bath until the odor of sulfur dioxide has largely disappeared.
Cool, dilute to about 100 cc. and add 35-40 cc. of the mercury-thiocyanate reagent
with vigorous stirring. The acid concentration at this point must not exceed 5 per
cent. Allow to stand for at least 1 hour, stirring occasionally; filter through a tared
Gooch crucible, wash with water containing 20 cc. of the mercury-thiocyanate reagent
per liter, dry at 105°C., and weigh. From this weight calculate the per cent of zinc
oxide in the sample, using the factor 0.16331.
ARSENIOUS OXIDE.
REAGENTS.
(a) Starch indicator—Prepare as directed under Paris green?.
(b) Standard arsenious oxide solution—Prepare as directed under Paris green’.
(€) Standard iodine solution—Prepare as directed under Paris green’.
(d) Standard potassium bromate solution—Prepare as directed under Paris green,
page 33.
(e) Standard potassium iodate solution.—Prepare as directed under Paris green»
page 34.
DETERMINATION.
Bromate Method.
Transfer a 25 cc. aliquot of the solution, prepared for the determination of zinc, to
a 500 cc. Erlenmeyer flask, add 20 cc. of concentrated hydrochloric acid and dilute to
100 cc. Heat to 90° C. and titrate with standard bromate solution, as directed under
Paris green.
Todate Method.
Transfer a 25 ce. aliquot of the solution, prepared for the determination of zinc, to
a 300-500 cc. glass-stoppered bottle, add 30 cc. of concentrated hydrochloric acid and 5
cc. of chloroform, and titrate with standard iodate solution, as directed under Paris green.
C. C. Hedges’ Method Modified,
Proceed as directed under Paris green*.
WATER-SOLUBLE ARSENIC.
Proceed as directed under lead arsenate*.
1 Trans. Am. Inst. Met., 1914, 8: 146; J. Am. Chem. Soc., 1918, 40: 1036.
2 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 53.
3 Tbid., 55.
+ Ibid., 59.
48
ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
TABLE 6.
Cooperative results on zine arsenite.
ANALYST
R. H. Robinson
AV EPABO). «ciclercuseieo dss Shree
F. L. Hart
PAV ET ARO) eyeaisnvaivicielevetotarhetetsieietehers
C. F. Sheffield
INVEFARO see onsets wasters eter
H. D. Young
IMGT OODOOO AEBS OOO OM OE
J. J. T. Graham
Asyerage i ira v Gis isets Gaistepcce ieee
General Average................
ARSENIOUS OXIDE
ZINC
OXIDE | promaTE | ropaTE | HEDGES’
METHOD | METHOD | METHOD
MODIFIED
per cent per cent per cent per cent
56.49 40.58 40.57
56.39 40.58 40.57
56.46 ans 3000
56.47
56.38
56.41
56.43 40.58 40.57
40.08 40.05 39.95
40.14 40.00 Seoe
40.11 40.03 39.95
56.36
56.44
56.40
56.67 39.88 39.93
56.77 39.90 39.93
56.72 39.89 39.93
56.92 40.07 40.20 40.00
56.97 40.01 40.08 40.00
56.99 40.07 40.08 40.06
57.02 Aipicid Reece Baty 3
56.98 40.05 40.12 40.02
56.62 40.15 40.16 40.00
COMMENTS BY ANALYSTS.
[Vol. V, No. 1
WATER-
SOLUBLE
ARSENIC
(METALLIC)
per cent
Trace, less
than 0.01
0.06
R. H. Robinson.—No difficulty was experienced in obtaining check results by the
different methods for arsenious oxide in zinc arsenite.
In the determination of zinc in zinc arsenite, potassium thiocyanate was used in the
mercury-thiocyanate reagent.
tation of the zinc was made at the same temperature.
Excellent duplicate results were obtained when precipi-
The results were obtained at
26-28° C., the temperature of the laboratory at the time the determinations were
made.
It was found, however, that when all solutions were cooled to 15-18° C. and
1921] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 49
maintained at that temperature until filtered, the results were about 0.2 per cent
higher. Contrary to Jamieson’s statement that ‘‘drying at 105° C. for 1 hour was
sufficient”, it was necessary to dry in an electric oven at 105° C. for about 10 hours
to obtain constant weight.
DISCUSSION.
The results for arsenious oxide, with one exception, agree fairly well. While one of
the analysts reports slightly higher values than the other cooperators, his results agree
very closely by the different methods.
The method for water-soluble arsenic gives good results and is already official for a
number of arsenicals.
In the mercury-thiocyanate method for zinc oxide there is some variation in the re-
sults by the different analysts, but the different determinations by the individual analysts
agree quite closely. One analyst thinks that differences in temperature cause a varia-
tion in the results. The referee has found that sets of determinations made at different
times, while checking quite well in each set, often vary slightly between sets. He has
made a partial study of the cause of this variation, but is not in a position to draw any
definite conclusions at present. Drying the precipitate for 1 hour at 105° C. produced
constant weight for him in all cases. Analysis of this sample by the phosphate method
gave a zinc oxide content of 57.28 per cent, which is slightly higher than the results
submitted by any of the analysts.
RECOMMENDATIONS.
After consultation with Committee A, the referee decided to make no
recommendation to the association for the adoption of the iodate method
for the determination of total arsenic and arsenious oxide. Although the
results by this method are excellent, the bromate method is equally
accurate, more easily manipulated, and the materials required are
cheaper.
It is recommended—
(1) That the hot bromate method, page 34, be adopted as an official
method for the titration of the acid distillate in the official distillation
method for the determination of total arsenic.
(2) That the hot bromate method, page 34, for the determination of
arsenious oxide in Paris green be adopted as an official method.
(3) That the bromate method for the determination of arsenious
oxide in calcium arsenate, page 36, be adopted as an official method.
(4) That the tentative method for the determination of arsenious
oxide in lead arsenate}, be adopted as a tentative method for the deter-
mination of arsenious oxide in calcium arsenate.
(5) That the official method for the determination of water-soluble
arsenic in lead arsenate, page 37, be adopted as official for the determina-
tion of water-soluble arsenic in calcium arsenate.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 59.
50 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
(6) That the modified method for calcium oxide, page 41, be adopted
as a tentative method.
(7) That the method for calcium oxide, page 37, be amended by elimi-
nating the words, ‘‘or ignite and weigh as oxide’’, and when so
amended that it be adopted as a tentative method.
(8) That in the ‘‘General procedure for the analysis of a product con-
taining arsenic, antimony, lead, copper, zinc, iron, calcium, magnesium,
etc.’’, page42, the methods for lead oxide and copper be adopted as official
methods and the method for zinc oxide be adopted as a tentative method.
(9) That the official distillation method! be adopted as an official
method for the determination of total arsenic in London purple.
(10) That the zinc oxide-sodium carbonate method? be adopted as an
official method for the determination of total arsenic in London purple.
(11) That the mercury-thiocyanate method for zinc oxide in zine
arsenite, page 47, be adopted as a tentative method.
(12) That the bromate method for the determination of arsenious
oxide in zinc arsenite be adopted as an official method.
(13) That the official method for the determination of water-soluble
arsenic in lead arsenate, page 47, be adopted as official for the determina-
tion of water-soluble arsenic in zinc arsenite.
(14) That the official distillation method! be adopted as an official
method for the determination of total arsenic in magnesium arsenate.
(15) That a study be made of methods for the determination of arseni-
ous oxide, water-soluble arsenic and magnesium in magnesium arsenate.
PICKERING BORDEAUX SPRAYS.
By F. C. Coox (Bureau of Chemistry, Washington, D. C.).
The copper in Bordeaux spray has generally been considered to be in
the form of copper hydrate. Pickering, an English chemist, studied the
composition of Bordeaux and of other sprays, known as Pickering sprays,
made by mixing dilute solutions of copper sulfate with lime water. He
found the copper in Bordeaux and in the Pickering sprays to be present
as basic sulfates of copper, the amount of lime used determining the com-
position of the basic sulfate. Pickering made laboratory tests, passing
carbon dioxide through suspensions of the different sprays, and deter-
mined the amount of copper made soluble. He found eight to fifteen
times as much copper sulfate re-formed from the different Pickering
sprays as from Bordeaux spray. The conclusion was drawn that the
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 54.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 397.
1921] COOK: PICKERING BORDEAUX SPRAYS 51
Pickering sprays prepared with lime water, in place of milk of lime, were
many times more efficacious per unit of copper than the standard Bor-
deaux sprays.
In 1915, when copper sulfate increased in price to twenty-five and
thirty cents a pound in certain parts of this country, C. L. Alsberg and
J. K. Haywood of the Bureau of Chemistry arranged with the Bureau
of Plant Industry for cooperative tests to determine if the Pickering
sprays, which required less copper sulfate than Bordeaux, would give
as good control of fungous diseases as obtained with standard Bordeaux.
The tests, which extended over three seasons, were made on apples,
‘grapes, cranberries and potatoes.
The cooperation of the Maine Agricultural Experiment Station was
secured for the potato tests. The Pickering sprays, because of their
caustic properties, can not be recommended for apples in Virginia or
for grapes in Virginia and New Jersey. Whether similar results will fol-
low elsewhere can only be determined by tests in different localities. The
results on cranberries in New Jersey and on potatoes in Maine were
satisfactory. The late blight, phytophthora infestans, of potatoes was con-
trolled and the yields increased as with regular Bordeaux. The amount
of copper sulfate in the Pickering spray successfully used on potatoes
was 46 per cent less than in the 5-5-50 Bordeaux used. The Pickering
sprays are easily applied and involve less wear and tear on the apparatus
than Bordeaux sprays.
The past two seasons data have been secured which indicate strongly
that copper sprays, such as Bordeaux and Pickering, not only increase
the yield of tubers but increase the solid matter of the tubers, i. e., in-
crease the food value. The results of the experiments have been pub-
lished by the Department of Agriculture!. It is hoped that the Pickering
sprays may be tried on different crops in various parts of the country
in order to determine their value.
A barium water spray was also used on apples and potatoes with
satisfactory results. Such a spray effected a considerable saving of cop-
per and gave an increased yield of potatoes. It has the advantage of
being prepared with barium hydrate, which possesses some slight fungi-
cidal properties and which dissolves more readily than lime in water and
leaves no insoluble residue.
1U.S. Dept. Agr. Bull. 866: (1920).
52 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
REPORT ON SOILS.
By W. H. MacInrtire (Agricultural Experiment Station, Knoxville,
Tenn.), Referee.
As directed by the association, the referee has undertaken a study of
the sulfur problem. It so happened that this subject has been studied in
the laboratory of the referee during the past six years from the view-
point of native soil sulfur and precipitated sulfur, through the medium
of forty-six lysimeters. On the other hand, the problem of added sulfur,
in three forms, iron sulfate, iron pyrites and flowers of sulfur, has been
under investigation during the past three years through the installation
of twenty-two lysimeters, installed primarily for sulfur-addition research.
Since this association directed that the problem be recognized and
studied by the referee, the work has been extensively supplemented
under laboratory-control conditions where the pure chemistry of sulfur
transformations characteristic of soils is being investigated. One assis-
tant has been giving his full time to these laboratory studies and a number
of intensely interesting and indicative findings have been recorded. It
is hoped that these studies will be completed in time to present the sum-
marization of results at the 1921 meeting of the association.
The referee has devoted some months of study upon an attempt to
perfect an analytical method which would recover for determination all
of the sulfur content of soils. Since the work, though well advanced,
lacks much of completion, it does not seem necessary to burden the
association with its details at this time. Briefly summarized, however,
it may be said that a number of different procedures were tried upon
three soils in an effort to secure a full recovery of added sulfates of sodium
and magnesium. The original soil was run parallel with portions
impregnated with definite additions, as aliquots of one or more standard
solutions. The methods of procedure were as follows:
(1) The magnesium nitrate incineration procedure.
(2) The sodium peroxide incineration and fusion.
(3) Boiling with concentrated nitric acid; filtration through Biichner;
addition of bases; evaporation and heating to convert iron salts to oxides,
followed by boiling with acetic acid and filtration, to effect solution of
sulfates, and removal of iron oxides.
(4) Boiling with aqua regia; filtration through Biichner; addition
of bases; evaporation and heating to convert iron salts to oxides, fol-
lowed by boiling with acetic acid and filtration, to effect solution of
sulfates, and removal of iron oxides.
(5) Boiling with nitro-hydrofluoric acid; filtration through Biichner;
addition of bases and elimination of hydrofluoric acid by repeated evap-
1921] MACINTIRE: REPORT ON SOILS 53
orations with hydrochloric acid; heating to convert iron salts to oxides,
followed by boiling with acetic acid, and filtration to bring sulfates into
solution and remove iron oxides.
(6) The J. Lawrence Smith method and bromine additions.
(7) Incineration with calcium and magnesium carbonates and nitrates
with bromine addition to solution.
The incinerated residues were extracted separately with water, acetic
acid and hydrochloric acid. None of these procedures effected a full
recovery of even the added sulfur, much less the total of native and
added amounts. Native barium of the soil was found to be one inhibitory
factor in the partial recovery of sulfur. The rehydration of the silica
_ by acid additions seemed to be a further, if not major, deterrent to sul-
fate recovery. The insolubility of ignited sulfates appeared also to con-
tribute to the incomplete leaching of sulfates from the insoluble residues.
The one procedure, as carried out with one or more variations in detail
of technique, which produced a total, equivalent to the native and added
sulfur, as sulfates, was as follows:
Mix 25-gram charges of soil with ammonium nitrate, ammonium chloride and cal-
cium carbonate by thorough dry pestling. Transfer to two 15 cc. platinum or Vitreosil
crucibles and heat in an electric furnace for 1 hour at full heat. After cooling, remove
and pulverize, if necessary. Hydrate the calcium oxide and then add water to a volume
of about 200 cc. Heat nearly to boiling on an electric plate, or sulfur-free flame, and
throw onto a Biichner filter. Wash to a volume of 1 liter. Then add an excess of acetic
acid to the residue (volume of 200 cc.); heat and repeat the Biichner filtration; and
washing to 1 liter. Evaporate and combine the filtrates. Precipitate barium sulfate
from a volume of 400 cc.
Nore: It has not yet been determined whether it is essential to remove most or all
of the calcium and magnesium. This has been done by the addition of ammonium
carbonate to the separate water and acetic acid filtrates; the elimination of ammo-
nium chloride by metathesis with nitric acid, followed by two evaporations with
hydrochloric acid.
An effort will be made to perfect this tentative procedure.
Since it was impossible to secure an associate of experience who could
devote sufficient time to a further study of the lime absorption coefficient,
this work was not continued during the past year.
RECOMMENDATIONS.
-
It is reeommended—
(1) That work be continued during the ensuing year in an effort to
perfect the suggested method or some other procedure which will insure
the complete recovery of total soil sulfur.
(2) That a committee of three be appointed by the president of this
association, to confer with a similar committee, already appointed, from
the American Society for Testing Materials, relative to methods of analy-
54 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
sis and proposed uniform legislation for the control of the sale of agri-
cultural lime.
No associate referee on sulfur in soils was appointed and no special
report on this subject was presented.
REPORT ON TESTING CHEMICAL REAGENTS.
By W. D. Coxtins (U.S. Geological Survey, Washington, D.C.), Referee.
The purity and strength required for reagents to be used in the analyti-
cal methods of this association are not markedly different from the
requirements for reagents for any other careful analytical work. There-
fore there would seem to be no need for extensive study with collabo-
rative work on this subject by the association. The reports of past refer-
ees are in harmony with this conclusion.
The worst feature of the situation in regard to reagents is the lack of
reliability. This does not seem to be caused so much by lack of methods
of testing or lack of knowledge of manufacturing processes, as by failure
to keep the purity and reliability up to the standard permitted by the
knowledge which is at hand.
Manufacturers and dealers do not have enough specific complaints
of low quality to justify them in believing that their products are on
the whole much below the standard which may reasonably be expected
for a reagent manufactured and sold in a commercial way. They are
inclined to believe that on the whole they are doing pretty well. The
Committee on Guaranteed Reagents and Standard Apparatus of the
American Chemical Society is endeavoring to secure data to show
whether manufacturers are justified in this belief and to help members
of the society to secure satisfactory reagents. If enough information in
regard to specific instances of deliveries of poor reagents can be obtained,
it will be possible to direct purchasers to the best sources for individual
reagents and to assist manufacturers to bring their standards up to the
level of the general demand. In order to help in this work the following
recommendations are made:
RECOMMENDATIONS.
(1) That the association declare itself in favor of cooperating with
the Committee on Guaranteed Reagents and Standard Apparatus of
the American Chemical Society in the collection of data in regard to
the quality of reagents on the market.
(2) That the secretary, or referee on testing chemical reagents, be
instructed to transmit a statement of this action to the proper official
of each institution represented in the membership of the association
1921] BIDWELL: REPORT ON CRUDE FIBER 55
and request that the purchasing agent or some other official of the insti-
tution send to the Committee on Guaranteed Reagents and Standard
Apparatus of the American Chemical Society a carbon copy of each letter
written to a manufacturer or dealer calling attention to a_ specific
instance of delivery of an unsatisfactory reagent.
No report on foods and feeding stuffs was made by the referee.
REPORT ON CRUDE FIBER.
By G. L. Binwett (Bureau of Chemistry, Washington, D. C.), Referee.
The referee has had very satisfactory cooperation, and wishes both to
thank the cooperators and to ask their cooperation in the work next
year. In February samples were sent to about fifty collaborators with
the request that the crude fiber be determined by the methods in use at
their laboratories; also, that the method used be reported. The methods
differed so much that work was started in the referee’s laboratory to see
what effect these various differences might have. The results of that
work are given in a separate paper, page 58.
The results on the first sample are shown in Table 1.
TABLE 1.
Cooperative results on crude fiber, Sample No. 1.
LABORA- LABORA-
LABORATORY CRUDE TORY CRUDE TORY CRUDE FIBER
NUMBER FIBER NUMBER FIBER NOMBEH
per cent per cent per cent
We 8.71 1 8.77 22 9.08
W3 8.75 2 8.68 23 8.74
A 8.35 3 8.25 24 8.25
B 8.68 4 7.50 25 8.19
Cc 9.06 5 7.54 26 8.81
D 8.79 6 8.84 27 8.66
E 9.14 a 8.98 28 8.43
F 8.85 8 8.74 29 8.52
G 8.10 9 8.66 30 8.33
H 9.05 10 8.55 31 8.62
I 8.57 11 8.02 32 8.77
4 8.59 12 8.52 it 33 9.48
K 8.31 13 8.33
L 7.58 14 8.51 Average of all
M 8.45 15 8.36 samples 8.56
N 8.79 16 8.63
O 8.75 17 8.61
P 8.78 18 8.47
Q 8.04 19 9.00
R 8.44 20 8.48
SS) 8.44 21 8.84
56 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Later, a second sample was sent to a portion of the first list with the
same directions. This was a cottonseed meal. The results follow:
TABLE 2.
Cooperative results on crude fiber, Sample No. 2.
ee CRUDE FIBER fapetaca sie CRUDE FIBER
per cent per cent
WwW 12.85 L 12.69
W2 12.80 M 13.40
W3 12.89 N 12.62
Wa 12.79 O 12.06
A 13.20 12 11.46
B 12.54 10) 11.84
Cc 12.62 R 11.89
D 12.83 S) 12.80
E 12.09 ——
F 12.12 Average of all
G 12.15 samples 12.61
H 11.82
I 13.49
J 13.73
K 13.25
Still later, a third sample was sent to the full list of collaborators
with a method that has been found to give good results. The results
obtained are given in Table 3.
TABLE 3.
Cooperative results on crude fiber, Sample No. 3.
LABORATORY LABORATORY
NUMBER CRUDE FIBER NUMBER CRUDE FIBER
per cent per cent
Wi 13.88 1 13.35
We 13.89 2 14.09
Ws 13.90 3 13.25
Wa 13.65 4 13.14
A 13.44 5 13.75
B 13.44 6 13.86
Cc 13.60 uf 15.80
D 13.65 8 14.60
E 14.22 9 13.51
F 13.00 10 14.07
G 13.21 il 14.48
H 15.50 12 13.05
I 13.91 13 13.81
J 13.01 14 13.69
K 12.90 15 12.75
L 13.17 16 12.66
M 13.02 17 13.43
N 13.32 —
O 13.44 Average of all
samples 13.65
a |
Or
1921) BIDWELL: REPORT ON CRUDE FIBER
These results vary about as much as those on Sample No. 1, but this
can be explained on the basis that it was a more or less new procedure
for the analysts. In the referee’s opinion, these results do not justify
the recommendation that this method be adopted by the association
but are good enough to justify a continuation of this work.
The referee has been asked to recommend to the association several
additions to the official method. This has not been done for the following
reasons: All of the feed methods can be classed as definitive methods,
that is to say, the definition of the name of the result is the method used
in obtaining that result. For instance, the percentage of crude protein
is not the exact percentage of protein by weight in a sample but is the
‘result obtained by multiplying the percentage of nitrogen obtained by
an approved method by the factor 6.25. There is no other feed method
that is so definitive, however, as the crude fiber method. Almost any
change that can be made and still keep within the method as it is at
present will make some change in the results. The foregoing tables show
how much the values may vary among laboratories that turn out good
work. In the opinion of many, this condition will not be improved until
the method is so changed that all analysts will run this determination
in exactly the same way. To accomplish this, the method must describe
and specify each step in detail and must have just as few optional details
as possible. In other words, all must use the same kind of condensers,
filtering media, flasks, crucibles and the same degree of heat.
When this is done, concordant results will be obtained as is shown by
the results marked W:, We, Ws, and W, in Tables 1, 2, and 3 which are
the results obtained by analysts in the Bureau of Chemistry at Washing-
ton working wholly independently but using precisely the same method.
The referee plans to try to ascertain the reasons for the differences
in Table 3 and, by changing the method, see if better results can not be
obtained. Then the referee hopes to be able to recommend a precise
method for crude fiber. It is felt that such a method, if followed, will
give results that will be more uniform than can be obtained from the
present one.
RECOMMENDATION.
It is recommended that the crude fiber method be further studied.
58 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
A STUDY OF THE DETAILS OF THE CRUDE FIBER
METHOD.
By G. L. Bipwett and L. E. Borst (Bureau of Chemistry, Washing-
trove, 1D), (Ob)
The crude fiber question has been under discussion by feed chemists
for several years, yet, after all the collaborative work that has been done
and all the discussion that has taken place, there still exists much dif-
ference of opinion in regard to this matter. Considerable difficulty has
been experienced by many analysts in securing concordant and satis-
factory results. In view of this, it would seem that the official method},
adopted years ago, is unsatisfactory. This condition may possibly be due
to the fact that the official method is not given in sufficient detail and
many chemists introduce variations which have a material effect upon
the results of the determination, yet they feel they are still within the
bounds of the official method. While some of the trouble may be due to
difficulties in manipulation, it would seem that if a method were given
in precise terms experienced men would have no trouble in securing con-
cordant results.
This work has brought out the fact that all chemists should be brought
to realize that this method is purely a definitive one; that is, crude fiber
is defined by the method just as volatile combustible matter in coal is
defined by the method, and is nof the determination of a definite substance
like calcium in limestone. It has been found that some chemists seem to
think an attempt is being made to determine a definite substance, cel-
lulose. This is not the case, however, for, when cellulose in its various
forms is determined, results are obtained which differ from those of crude
fiber. It follows, then, that the determination must be made by the dif-
ferent chemists in exactly the same way in every detail in order to obtain
concordant results, for very slight changes make appreciable differences.
The foremost object of this paper is to demonstrate the effect of small
changes that probably come within the bounds of the official method,
and to determine what details must be included in a proposed method
to make it absolutely satisfactory. A method has been developed, after
much work, that will give concordant results if care is taken to follow
it exactly. All results tabulated in this paper were obtained by using the
following method as a basis, with such variations as may be used specifi-
cally stated.
REAGENTS.
Dilute sulfuric acid solution —Contains 1.25 grams of sulfuric acid per 100 cc.
Dilute sodium hydroxide solution—Contains 1.25 grams of sodium hydroxide per
100 ce., free, or nearly free, from sodium carbonate.
1 Assoc. Official Agr. Chemisls, Methods. 2nd ed., 1921 97
1921] BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 59
The strength of these solutions should be accurately checked by titration.
Asbestos.—Previously treated with acid and alkali and ignited.
APPARATUS.
Liebig condenser (about 15 inch).
Container.—Any container that will give 14 inches depth of boiling solution and
allow the use of a Liebig condenser.
Funnel.—Any ribbed funnel.
Linen.—Linen should be of such character that while filtration is rapid practically
no solid matter passes through.
DETERMINATION.
Extract 1-2 grams of the dry material with ordinary ether, or the residue from the
ether extract determination may be used, and transfer the residue, together with 3-1
gram of asbestos, to the assay flask. Add 200 cc. of boiling 1.25% sulfuric acid and digest
for 30 minutes. Filter through linen, wash thoroughly and digest 30 minutes with
1.25% boiling sodium hydroxide. Filter through a prepared Gooch crucible, wash
thoroughly, dry, weigh, incinerate and weigh again. The difference in weight is taken
as crude fiber.
In undertaking this work the first problem confronted was to obtain
a sample that would give the same results day after day; in other words,
one that was efficiently ground and thoroughly mixed. After experiment-
ing for some time, a mixture of 25 per cent alfalfa and 75 per cent corn-
meal, ground to pass a 40-mesh sieve, was found to give very close checks
over a period of several weeks. The results of the series of determinations
are shown in the following table:
TABLE 1.
Individual determinations of crude fiber on test sample.
NOVEMBER 3 NOVEMBER 5 | NOVEMBER 13 DECEMBER 3 JANUARY 15 FEBRUARY 10
per cent per cent per cent per cent per cent per cent
9.48 9.55 9.60 9.59 9.38 9.52
9.46 9.40 9.63 9.50 9.39 9.46
9.44 Fr or Mac 9.45 es 9.54
9.36 9.60 9.64 9.42 9.46 Noses
The average of all the results obtained was 9.50 per cent of crude fiber.
Having prepared a satisfactory sample, the next step was the deter-
mination of the efficiency of different condensers. It was found that
various types of condensers were being used by the different collaborators
and the following list includes most of them:
1. Watch glasses.
2. Round-bottomed flasks containing cold water.
3. Round-bottomed flasks with a stream of cold water passing through.
4. Funnels.
5. Kjeldahl condensing bulbs.
6.
Air-cooled glass tubes.
60 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
WATCH GLASSES.
Four determinations on the above-mentioned sample were made accord-
ing to the method with the exception that a watch glass' was used to
cover the mouth of the container in place of a Liebig condenser. The fol-
lowing results were obtained: 9.26, 9.11, 9.10 and 9.25 per cent of crude
fiber; average, 9.18 per cent. These figures indicate that this modifica-
tion of the method has caused low results and is undoubtedly due to
evaporation, for the stronger the solution the greater the action upon
the material.
ROUND-BOTTOMED FLASKS CONTAINING COLD WATER.
In place of Liebig condensers, bottles filled with cold water were
placed upon the container and four determinations made with results
as follows: 9.30, 9.27, 9.23 and 9.10 per cent of crude fiber; average, 9.23
per cent. These condensers proved partially satisfactory for the first
10 minutes; then the water in the bottles became warm and there was
a concentration of solution, due to the escape of water vapor around
the junction of the flask and bottle, causing the low results.
ROUND-BOTTOMED FLASKS WITH A STREAM OF TAP WATER PASSING THROUGH.
With this variation in the method, the following results were obtained:
9.27, 9.32, 9.30 and 9.28 per cent of crude fiber; average, 9.29 per cent.
This possibly is more efficient than other types except, of course, the
Liebig. Loss by evaporation and inability to control frothing, which is
encountered in some samples, are objections to this modification. Al-
though this type of condenser is used to quite an extent the results show
0.2 per cent less fiber than when Liebig condensers are used.
FUNNELS.
In testing the efficiency of funnels as condensers, two sets of deter-
minations were made. In one set no attempt was made to keep the vol-
ume to 200 cc. and the following results were obtained on four deter-
minations: 9.10, 9.02, 9.11 and 9.00 per cent of crude fiber; average,
9.06 per cent. In the other set, water was occasionally added, in order
to maintain the original volume, with the following results: 9.40, 9.32,
9.28 and 9.42 per cent of crude fiber; average, 9.36 per cent.
These two sets of results show conclusively that funnels are unsatis-
factory as condensers and that they are the most inefficient of all types
investigated. The addition of water helps to a certain extent but results
obtained with the use of funnels for condensers will never be so satis-
factory as those obtained by the use of Liebig.
1J. Ind. Eng. Chem., 1910, 2: 281.
1921] | BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 61
KJELDAHL CONDENSING BULBS.
The Kjeldahl condensing bulbs were next tried with the following
results: 9.38, 9.40, 9.36 and 9.31 per cent of crude fiber; average, 9.36
per cent.
These results are not so good as obtained with the Liebig condenser.
AIR-COOLED GLASS TUBES.
Glass tubes about 20 inches long and } inch in diameter were used
for condensers with the following results: 9.28, 9.33, 9.36 and 9.26 per
‘cent of crude fiber; average, 9.31 per cent. This type of condenser is,
of course, very inexpensive and easy to manipulate. However, the
results are lower than those obtained with the Liebig condenser, due
to loss by evaporation which causes concentration of solution resulting in
additional action on the charge.
From these figures it can be readily seen that condensers play a very
important part in this determination. Concentration of solution due to
evaporation noticeably lowers the results. To obtain concordant results
one type of condenser must be used by all. The Liebig water-jacketed
condenser’ gives the most satisfactory and uniform results of any type
used and since it is standard equipment there should be no objection to
its use.
The next step was to determine just what effect a delay in the acid
and alkali filtration would have upon the results. Delays of 7, 14 and 28
minutes were made on both acid and alkali filtrations.
TABLE 2.
Crude fiber obtained by a delay in acid filtration.
DELAY OF 7 MINUTES DELAY OF 14 MINUTES DELAY OF 28 MINUTES
per cent per cent per cent
9.38 9.35 9.32
9.32 9.38 9.26
9.21 9.30 9.24
9.18 9.35 9.19
Stayer 9.42 Betas
9.36
Average. .9.27 9.36 9.25
Where the acid filtration was delayed 7 minutes a lowering of the
results is noted. This is due to the additional time that the acid is allowed
to act upon the charge. The abnormal results noted in the 14-minute
1J. Ind. Eng. Chem., 1910, 2: 281.
62 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
periods may be due to a combination of two actions: the further disin-
tegrating action of the acid, due to additional time, which would lower
results; and the precipitation of material once dissolved, due to lower-
ing of temperature of solution while standing, which would raise results.
The results from the 28-minute period show an additional drop in fiber
corresponding somewhat to the 7-minute period. The point emphasized
by these results is that unless the solution is filtered immediately after
removal from the flame, additional action takes place which noticeably
affects the results and no sample requiring more than 5 minutes for acid
filtration should be reported.
DELAY IN ALKALI FILTRATION.
Four determinations were carried through the regular acid and alkali
digestion but immediately after the expiration of the 30 minutes’ alkali
boiling they were allowed to stand for periods of 7, 14 and 28 minutes
with the following results:
TABLE 3.
Crude fiber obtained by a delay in alkali filtration.
DELAY OF 7 MINUTES DELAY OF 14 MINUTES DELAY OF 28 MINUTES
per cent per cent per cent
9.52 9.48 9.48
9.48 9.45 9.43
9.44 9.51 9.51
9.50 9.49 9.35
Average. .9.49 9.48 9.44
No great difference is noticed in the results by delaying the alkali
filtration on this sample!. In order to determine whether this variation
in the method would give similar results upon a feed having different
properties, the same experiment was tried with cottonseed meal. Deter-
minations were made upon a cottonseed meal having a fiber content of
13.52 per cent with the following results:
TABLE 4.
Crude fiber obtained in cottonseed meal by a delay in acid filtration.
DELAY OF 7 MINUTES DELAY OF 14 MINUTES DELAY OF 28 MINUTES
per cent per cent per cent
13.69 13.71 13.44
13.74 13.63 13.61
13.22 13.57 13.50
13.47 13.47 etree
Average. .13.53 13.60 13.52
1 J. Ind. Eng. Chem., 1915, 7: 676.
1921] BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 63
TABLE 5.
Crude fiber obtained by a delay in alkali filtration.
DELAY OF 7 MINUTES DELAY OF 14 MINUTES DELAY OF 28 MINUTES
per cent per cent per cent
13.49 13.62 14.16
13.30 13.37 14.00
13.04 13.67 14.14
ere 13.95 14.31
Average. . 13.28 13.65 14.15
In delaying acid filtration, little change is noted in the results, but in
the alkali filtration with 7 minutes’ delay, the results are lower, due to
the additional action of the hot alkali. In the 14- and 28-minute periods,
where the solutions have had a chance to cool somewhat, reprecipitation
of material once dissolved occurs and the results are noticeably higher.
These two samples are good examples of low and high protein feeds.
The next variation of the method studied was the effect of different
types of containers upon the fiber result. The following types of con-
tainers were used and the results obtained are as follows:
TABLE 6.
Crude fiber obtained using different containers.
500 cc. ERLENMEYER FLASK 750 cC. ERLENMEYER FLASK 1 LITER ERLENMEYER FLASK
per cent per cent per cent
9.41 9.61 9.23
9.55 9.59 9.52
9.38 9.37 Sheree
9.34 Bee
Average. . 9.42 9.52 9.38
A study of these results indicates that the assay beaker and the 500
and 750 cc. Erlenmeyer flasks are satisfactory as containers. The results
obtained with a 1-liter Erlenmeyer flask, however, are not satisfactory
and this is due to the fact that it is practically impossible to prevent
charring around the sides of the container. With only 250 cc. of solution
in the flask there is not sufficient depth to prevent the sides of the flask
being heated to the charring point. On the other hand, the other con-
_ tainers will have at least 14 inches depth of solution in them and this is
sufficient to prevent charring.
It was noted that some analysts were not removing the ether extract
from the sample before determining crude fiber. This variation was
studied with the following results: 9.77, 9.62, 9.68 and 9.56 per cent of
64 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
crude fiber; average, 9.66 per cent. This is to be compared with an
average of 9.50 per cent obtained with the usual method.
These figures show that unless the ether extract is removed before
crude fiber is determined the results will be higher, the difference depend-
ing, of course, upon the amount of fat in the sample. In order to make
sure that the presence of the ether extract was increasing the fiber con-
tent, the percentage of fat in the sample was obtained and the amount
of soap calculated, which would be formed from this fat during alkali
digestion. Next, a fat-free charge was digested with 200 cc. of boiling
sulfuric acid, filtered and just before the alkali digestion was started the
caiculated amount of ivory soap was added and the determination con-
tinued in the regular way. The following results were obtained: 9.61,
9.68, 9.72 and 9.60 per cent of crude fiber; average, 9.65 per cent. These
results indicate that the presence of the soap has some inhibitive action
which is not clearly understood but it is probable that this action is
mechanical rather than chemical. Other samples were tried, including a
linseed meal with a high fat content. Here the difference was very much
greater, the presence of the fat making a difference of nearly 2 per cent
in the fiber results.
In carrying out this work a very interesting point was noted in con-
nection with the ether extract and it seems worth while to mention it
here, although the matter does not directly concern the crude fiber deter-
mination. A charge was taken which did not have the ether extract
“removed. It was digested with boiling 1.25 per cent sulfuric acid for 30
minutes and washed thoroughly. The residue was then completely dried
and the ether extract determined, which proved to be 5.63 per cent. This
was a gainof 1 per cent over the ether extract in the original sample, which
only contained 4.62 percent. No fat was present in the substance after the
alkali digestion, which shows that it was completely saponified during
this digestion. The increase in the fat content caused by the acid digestion
may have been due to the liberation of certain substances soluble in ether
which were held in the cells and cell membranes in such a way that they
were not obtained in the ordinary ether extraction.
Numerous inquiries have been made as to the effect of the degree of
fineness of the niaterial upon the fiber content. In order to more clearly
understand this matter the following work was undertaken. A sample of
alfalfa hay was divided into three portions. One portion was ground to
pass a 20-, one a 40-, and the other a 60-mesh sieve. Each portion was
mixed thoroughly and crude fiber determined with the following results:
1921} | BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 65
TABLE 7.
Crude fiber obtained on sample of alfalfa hay after grinding to different degrees of fineness.
20-MESH SIEVE 40-MESH SIEVE 60-MESH SIEVE
per cent per cent per cent
34.54 31.64 30.37
33.79 31.56 30.02
33.57 aevsrs’s Rxcetas
Average. .33.97 31.60 30.20
From these results it is apparent that the finer a sample is ground the
lower the fiber content will be. Also, better checks were obtained from
the sample passed through a 40-mesh sieve and this has uniformly proved
to be the case upon other work!. Ground alfalfa was selected because
of its high fiber content and because difficulty is usually experienced in
securing check results due to the different amounts of fiber in the leaves
and stems and the difficulty of properly mixing these parts.
The next point of interest was the study of different filtering media.
Many analysts have the idea that the chief trouble with fiber work is
due to the filtering material, linen, asbestos, or glass wool, which varies in
its physical characteristics and necessarily in filtering efficiency. The
reports from collaborators laid great stress upon different: grades and
quality of linen. The following results were obtained, using linen for
both filtrations and having no asbestos present: 9.27, 9.22, 9.27, 9.10
and 9.27 per cent of crude fiber; average, 9.23 per cent.
When linen was used for the first filtration and a Gooch crucible for
the second, and no asbestos was present, the following results were
obtained: 9.38, 9.35, 9.34, 9.28, 9.16 and 9.34 per cent of crude fiber;
average, 9.31 per cent.
When linen was used for the first filtration and filter paper for the
second, and no asbestos was present, the following crude fiber figures were
obtained: 9.37, 9.29 and 9.24 per cent; average, 9.30 per cent.
From these results two important conclusions are drawn:
(1) Regardless of the filtering material the results are practically the
same.
(2) These results are all about 0.2 per cent lower in fiber where no
asbestos is used.
Some chemists have made use of 350-mesh copper gauze as a filtering
medium and this was tried, both on the mixture of cornmeal and alfalfa
and on the straight cottonseed meal.
Filtering after acid digestion through 350-mesh copper gauze and
after alkali digestion through a prepared Gooch crucible gave the following
1 J. Ind. Eng. Chem., 1915, 7: 676.
66 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
results on a mixture of cornmeal and alfalfa: 9.48, 9.55, 9.46 and 9.58
per cent of crude fiber; average, 9.52 per cent. This is to be compared
with 9.50 per cent, the average obtained with the method ordinarily
employed. The following results were obtained when cottonseed meal
was filtered first through a copper gauze and then through a prepared
Gooch crucible: 13.85, 13.74 and 13.80 per cent of crude fiber, average,
13.80 per cent; and 13.93, 13.82 and 13.86 per cent of crude fiber, aver-
age, 13.87 per cent, when cottonseed meal was filtered first through linen
and then through a prepared Gooch crucible.
The results obtained with the use of copper gauze checked surprisingly
close with those obtained with linen and there seems to be no reason why
350-mesh copper gauze could not be used as well as linen. However, it
was found that the gauze is very expensive and there probably would be
objections to its use on this ground.
In order to make sure of the conclusions in regard to efficiency in
filtering media it was necessary to ascertain whether any of the charge
was passing through the linen cloths during filtration'. To determine
this, the acid filtrate with all the washings was caught directly in a weighed
Gooch crucible.
The following results were obtained from the same mixture of alfalfa
and cornmeal used in previous work: 0.0050 and 0.0058 gram. This
represents the amount of material which passes through the linen dur-
ing filtering and washing and was caught in the Gooch crucible.
A sample consisting of a mixture of ground alfalfa and cottonseed meal
was next tried and it was found that 0.0050 and 0.0075 gram passed
through linen.
This same sample was filtered through the 350-mesh copper gauze
with slightly higher results—0.0148 and 0.0136 gram.
A sample consisting of straight cottonseed meal was next tried, 0.0085
gram filtering through linen, and 0.0326 gram filtering through 350-
mesh copper gauze.
This last result shows more of the substance coming through the wire
gauze than through linen.
During this filtration work, many different grades of linen were used
with practically the same result in all cases. Wire of 350-mesh allows
more loss of material during filtration than linen but the writers are of
the opinion that the substance which passes through the filter is mostly
dissolved by the alkali and the loss, therefore, is negligible because the
results with wire and cloth are found to be almost identical.
1J. Ind. Eng. Chem., 1910, 2: 280.
1921] BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 67
Linen should be of such character that while filtration is rapid no
great amount of solid matter passes through. Many samples of
linen have been tested and linen of the texture previously mentioned
has always been found efficient, regardless of coarseness or fineness of
weave. This is one of the most interesting points developed, for it has
been regarded in the past that texture of linen was an important feature.
Work was undertaken to determine, if possible, just what effect the
presence of the asbestos had upon the charge. The following results
were obtained upon the mixture of cornmeal and alfalfa when asbestos
was present: 9.48, 9.46, 9.55 and 9.50 per cent of crude fiber, average,
_ 9.50 per cent; and 9.34, 9.35, 9.28 and 9.38 per cent of crude fiber,
average, 9.34 per cent when no asbestos was used. This shows a dif-
ference of approximately 0.2 per cent of fiber in this type sample.
The same procedure was tried with a sample of cottonseed meal:
13.85, 13.81, 13.58 and 13.54 per cent of crude fiber, average, 13.70 per
cent, was obtained when asbestos was used and 12.95, 12.97, 12.93 and
12.69 per cent of crude fiber, average, 12.89 per cent, when no asbestos
was used.
The above results show a difference of 0.82 per cent of fiber for this
type of sample. This may be accounted for by the much increased time
of filtration when no asbestos was used.
The same variation was tried upon a sample of high fiber con-
tent, for example, alfalfa: 31.64 and 31.56 per cent of crude fiber, average
31.60 per cent, was obtained when asbestos was used and 31.38 and
31.30 per cent of crude fiber, average, 31.34 per cent, when no asbestos
was used.
These results show the effect of the presence of asbestos in the fiber
determination upon various types of samples of varying fiber content.
The greatest difference is manifest in the cottonseed meal, where there
is only about 13.50 per cent of fiber, yet the difference here is greater
than for any other type of sample used.
After the fact was established that asbestos slightly raises the fiber
values, the question naturally arose as to how the asbestos produced
this effect. With this idea in mind, work was undertaken in which
asbestos was used in every step of the determination with the following
results: 9.10, 9.08, 9.07 and 9.12 per cent of crude fiber; average, 9.09
per cent. r
The following results were obtained when asbestos was added after
the acid digestion and before filtering the acid: 8.96, 8.96, 8.99 and 8.93
per cent of crude fiber; average, 8.96 per cent.
The loss noted is probably due to the inhibitive action of the asbestos
during acid digestion, although it is not known just what this inhibitive
action is!.
1 British Med. J., 1913, 2: 1360.
68 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
When asbestos was added after filtering the acid and just before
boiling with alkali the following results were obtained: 8.86, 8.84 and
8.88 per cent of crude fiber; average, 8.86 per cent.
This difference is probably due to the inhibitive action of the asbestos
and the additional action of the acid, due to slowness of filtration.
Another sample was run, adding asbestos after the alkali digestion
and just before alkali filtration with the following results: 8.78, 8.80
and 8.81 per cent of crude fiber; average, 8.80 per cent. The small loss
noted is, of course, attributed to the inhibitive action during acid and
alkali digestion and loss by slow filtration.
Asbestos was carried along in a separate container and added just
before alkali filtration with the following results: 8.76 and 8.74 per
cent of crude fiber; average, 8.75 per cent.
This result is almost identical with that obtained from eliminating
asbestos entirely.
From the above results it is evident that the difference in fiber content,
due to the presence of the asbestos, is caused mainly by the inhibitive
action during digestion and, to a smaller extent, by eliminating the loss
originally sustained by slowness in filtration.
Attention was next turned to the possibilities of errors during incinera-
tion. Experience has shown that crude fiber should be completely in-
cinerated at comparatively low temperatures, especially when asbestos
is carried along with the sample. The fibrous material present in feeds
is of such a nature that it should be completely burned off after 20 minutes
in an electric muffle at a dull red heat. Ignition at high temperatures
will tend to increase the loss which is calculated as crude fiber, as the
additional loss in weight is due to some action on the asbestos or vola-
tile salts present and certainly nothing closely related to fiber’.
CONCLUSIONS.
After due consideration of the figures given in this work, together
with the experience gained during this investigation, the writers con-
sider the following instructions and details to be such that if carefully
followed in every respect no difficulty should be experienced in getting
good checks when working upon cottonseed meal or other substances
by individual or different analysts.
REAGENTS.
Dilute sulfuric acid solution Contains 1.25 grams of sulfuric acid per 100 cc.
Dilute sodium hydroxide solution—Contains 1.25 grams of sodium hydroxide per
100 cc., free, or nearly free, from sodium carbonate.
The strength of these solutions must be accurately checked by titration.
Asbestos—The variety found best adapted for this work was tremolite, with a re-
fractive index of 0.1635 having fibers ranging in diameter from a maximum of 0.02-
0.002 mm.
1 J. Ind. Eng. Chem., 1915, 7: 676.
1921] BIDWELL-BOPST: DETAILS OF THE CRUDE FIBER METHOD 69
This asbestos first must be digested on the steam bath overnight with 5-10%
sodium hydroxide and thoroughly washed with hot water. It is next digested over-
night with 5-10% hydrochloric acid and again washed thoroughly with hot water.
Next, it is completely ignited in an electric muffle at bright red heat.
APPARATUS.
Liebig water-jacketed condenser.
Container.—Any container that will give 1} inches depth of boiling solution and
allow the use of a Liebig condenser.
It has been found especially advantageous to use an iron plate between the con-
tainer and flame: first, to distribute the direct heat which will prevent bumping; and
second, to prevent heat from coming in contact with the flask, thereby reducing char-
ring.
DETERMINATION.
Extract 1-2 grams of the dry material with ordinary ether, or use the residue from
the ether extract determination, and transfer the residue, together with approximately
1 gram of asbestos, to the container. Where the residue from ether extract is used
and the proper amount of asbestos has already been added, further addition is un-
necessary. Using a calibrated beaker, add 200cc. of boiling dilute sulfuric acid to the con-
tents of the container, which is immediately placed on the heating apparatus and con-
nected with a water-cooled Liebig condenser. It is essential that the contents of the
flask come to boiling within a minute after being placed upon the apparatus and that the
boiling continue briskly for 30 minutes. It is found best to rotate the flask with the
hand about every 5 minutes in order thoroughly to mix the charge. Care should be
taken to keep the sides of the flask above the solution free from the sample. A blast of
air conducted into the flask will serve to reduce the frothing of the liquid. Remove
the flask at the expiration of the 30 minutes and immediately filter through linen in
a fluted or ribbed funnel and wash with boiling water until the washings are no longer
acid.
Next wash the charge and adhering asbestos back into the assay flask with 200 ce.
of boiling dilute sodium hydroxide solution, using a 200 cc. wash bottle. By spread-
ing out the linen on a large glass funnel (the stem of which has been removed) and
using a 200 cc. wash bottle of sodium hydroxide, the transfer of the sample to the
original container is very easily accomplished. Previous to this, the sodium hydrox-
ide solution has been brought to boiling and kept at this temperature under a reflux
condenser, while in use. (The sodium hydroxide solution under the reflux conden-
ser is best transferred to a 200 cc. wash bottle by means of a bent tube through
which the liquid is forced by blowing into a tube connected with the top of the con-
denser.) Then place the flask on the heating apparatus, connect with reflux condenser
and boil for exactly 30 minutes. When running a set of fiber determinations the boil-
ing of the alkali should be so timed that the contents of the different flasks will reach
the boiling point approximately 3 minutes apart. This provides sufficient time for
filtration. The last filtration takes place directly through a Gooch crucible, which has
previously been prepared with a thin but close felt of ignited asbestos. Employ
suction and wash the contents thoroughly with hot water and then with about 15 ce.
of 95% alcohol.
Dry the crucibles with their contents to constant weight at 110° C. in an electric
oven, usually overnight. After weighing, incinerate the crucibles in an electric muffle
at a dull red heal until the carbonaceous matter has been removed, generally for 20
minutes, cool in a small, tight, efficient desiccator and weigh. The loss in weight is
taken as crude fiber.
70 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
SUMMARY.
(1) Liebig condensers are the most efficient that may be used.
(2) Samples taking more than 5 minutes to filter after digestion
should not be reported.
(3) Samples of high protein content, under delayed filtration, act
just opposite to those of low protein content.
(4) Any container having 13 inches of boiling depth may be used.
(5) The presence of fat in charge during fiber determinations noticeably
raises the results.
(6) There is a gain in ether extract when the charge has been previously
digested with 1.25 per cent sulfuric acid.
(7) The finer the material is ground the lower the fiber content. More
uniform results are obtained using a 40-mesh sieve.
(8) A method capable of giving concordant results is given.
THE DETECTION OF GROUND BRAN IN SHORTS.
By J. B. Reep (Bureau of Chemistry, Washington, D. C.).
Bran is a dairy feed and shorts is primarily a hog feed. The demand
for dairy feed in the summer when cattle are out to pasture is low and
since that is the season for hog raising, the demand for hog feed is high.
Consequently, the price of shorts is much higher than bran at this season
and sometimes it is fifteen or twenty dollars per ton higher. On the other
hand, in the fall when the cattle are no longer out to pasture the demand
for bran increases and at the same time the hogs are killed and marketed
and the demand for shorts decreases, with the result that the prices of
bran and shorts become more nearly equal. There is, then, a distinct
advantage to manufacturers to run their mills so as to produce all shorts
possible at certain seasons and there is a temptation to grind bran into
shorts which some manufacturers have difficulty in resisting. It is there-
fore necessary in control work to be able to detect it.
Somewhat over a year ago the following item appeared in the Com-
munity Miller and was called to the attention of the Bureau of Chemistry
by the Chief of the St. Louis Food and Drug Inspection Station:
MORE MONEY FOR YOUR BRAN.
We find that a great many mills are grinding their broad bran into shorts and are
netting 20 cents more per hundred weight. There are several inexpensive machines
on the market which are specially adapted for this work and they soon pay for them-
selves on bran alone, not to mention other grinding which they are able to do.
The practices advocated in this item would manifestly be in violation
of the Food and Drugs Act and the Bureau of Chemistry immediately
issued a press notice and wrote the Community Miller as follows:
1921] REED: DETECTION OF GROUND BRAN IN SHORTS 71
THe Community MILER,
Chicago, Illinois.
Gentlemen: The Bureau’s attention has been called to a short article on page 4 of
the “Community Miller’ for October, 1919, entitled ‘‘More Money for Your
Bran”. This article recommends the grinding of the bran for sale as shorts.
You may be interested to know that this practice is considered by the Bureau to be
in violation of the Federal Food and Drugs Act, if the product is brought within the
jurisdiction of that law. In fact, a number of actions have recently been instituted
under the law, based on shipments of reground bran sold as shorts.
We assume that you were not informed in regard to the attitude of the Department
in the matter, and are therefore taking this opportunity of calling it to your attention,
~ and suggesting that you advise your readers in order that they may not unwittingly
be led to violate the law. :
Respectfully,
Signed—C. L. Atssere, Chief.
A copy of the press notice was also sent to them. The following item,
which includes the press notice, appeared in the next issue of the Com-
munity Miller:
MISBRANDING.
In a recent issue we published a short article which had been submitted to us, relative
to how to realize 20c. per cwt. by grinding bran and mixing with middlings. We wish
to call our readers’ attention to the following announcement from the Department of
Agriculture and caution community millers regarding wrong labeling or misrepre-
sentation:
Seizures of shipments of stock feeds on the charge of adulteration and misbranding,
because of the sale of reground bran and screenings as shorts, have been made upon
the recommendation of officials of the Bureau of Chemistry, United States Depart-
ment of Agriculture, who are charged with the enforcement of the Federal Food and
Drugs Act.
The feed known to the trade as “‘shorts” contains more nutritive material than
ground bran and screenings, and sells in the market for a considerably higher price.
The sale of ground bran and screenings as shorts in the opinion of the officials, is not
only a fraud upon the purchaser, but is demoralizing to the feed industry. Honest
feed manufacturers who correctly label their feeds are placed at a disadvantage in
competing with manufacturers and dealers who put out cheaper products under the
names of higher priced ones.
The shipment into interstate commerce of ground bran and screenings, labeled as
shorts, constitutes both adulteration and misbranding under the terms of the Federal
Food and Drugs Act. Inspectors have been instructed to watch for interstate ship-
ments of adulterated and misbranded stock feeds. Action will be taken, say the ofli-
cials, in all cases found to be in violation of the law.
The matter of issuing a press notice informing the public that in the
opinion of the Bureau the practice was in violation of the Food and
Drugs Act was a simple matter, but the problem of detecting the pres-
ence of ground bran in shorts was something for the scientists of the
Bureau of Chemistry to solve. D. B. Bisbee of the St. Louis Food and
Drug Inspection Station was already working on the problem and the
72 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Cattle Food Laboratory was asked to study it also. The result was that
two entirely different methods were developed, one by Bisbee and one
by the Cattle Food Laboratory.
The wheat berry contains a germ and in the regular process of milling
wheat the germ necessarily finds its way into the shorts. It was obvious
that if a means of separating the germ from the shorts could be found the
solution of the problem would be well under way. Fortunately, themeans
of separation was at hand in the form of an apparatus devised by the Seed
Laboratory of the Department of Agriculture for the separation of light
seeds from the heavier ones. In this apparatus, use is made of a blast
of air passing up through bolting cloth. By careful manipulation of the air
pressure it is possible to make desired separations of lighter from heavier
materials.
G. P. Walton of the Cattle Food Laboratory had an apparatus of this
kind made and was using it in making separations of seed from lighter
material when this problem arose. The apparatus consists of a tube
about 14 inches in diameter and about 13 inches long, constricted
somewhat at each end. The bottom is covered with a piece of bolting
cloth and is inserted in a rubber stopper. It is then placed in an ordi-
nary suction flask and the flask connected with the blast through a drying
flask. At the top of the tube a gooseneck, with a flaring orifice, is inserted
and a suitable receptacle is placed under the orifice.
In order to see if the germ could be separated from the rest of the
shorts by means of this apparatus, a charge of shorts was introduced into
the tube and the air turned on. It was found that by proper manipulation
a residue was obtained which contained a considerable amount of germ
but there was also a large amount of the larger bran particles and pieces
of endosperm present and the separation was not at all satisfactory. The
sample was then ground to pass through a 20-mesh sieve and it was found
that by proper manipulation a fairly satisfactory separation of the germ
could be accomplished, sufficiently satisfactory, in fact, so that the addi-
tion of any considerable amount of ground bran could be detected in a
sample of shorts containing no ground screenings. The germ residue
seemed to run from 4 to 6 per cent on authentic samples of shorts.
The addition of so-called mill run of ground screenings complicated
matters. The small particles of grains and weed seeds weigh as much or
more than the germ particles and, consequently, they remain behind with
the germ. However, with experience acquired by running a great number
of known samples of shorts it is possible for one to judge fairly accurately
from the amount of germ present in the residue as to whether or not the
shorts contain ground bran. If the residue is less than 3 per cent the
suspicion is aroused that there is ground bran present or that the mill is
being manipulated. In these cases, an inspector is sent to the mill to
ascertain what is taking place. If the residue is less than 2 per cent, it
1921) REED: DETECTION OF GROUND BRAN IN SHORTS 73
is pretty certain that the product consists in whole or in part of ground
bran.
However, even if the residue is found to be greater than 3 per cent, it
is not necessarily concluded that no ground bran is present. If, in the
analyst’s judgment, the residue contains very little germ and is largely
screenings, the conclusion is reached that the product contains ground
bran even if 6 or 8 per cent residue is obtained, but these are extreme
cases and only those who have had a great deal of experience would be in
a position to judge. B. H. Silberberg of the Microchemical Laboratory
_ has followed this work very closely and has assisted in making most of
the determinations. Her results agree very closely with those of the
writer, and it seems probable that others with sufficient experience would
agree closely in most cases.
The details in carrying out this determination are as follows:
Grind the sample to pass a 20-mesh sieve. Make the determination with 10 grams
of the material but, owing to the fact that the apparatus will not handle 10 grams
very satisfactorily, weigh out two 5-gram samples. Introduce the first 5-gram sample
into the apparatus, turn on the blast gradually and make a rough separation but leave
sufficient residue to be certain that none of the germ is carried over. Then remove
the residue, add the second 5 grams and repeat the process. Then replace the residue
from the first 5 grams and place a clean receptacle under the gooseneck. Clean the
whole residue by repeating the blasting process until satisfied that all other material
possible is separated from the germ.
In carrying out the test, the flour will pass over first and an idea may
be obtained as to about how much is present. The fact that a sample
contains very little flour dees not necessarily indicate that the product
is not shorts. In fact, the largest and most efficient mills produce shorts
with very little flour, while shorts from smaller, less efficient mills often
contain considerable flour. It would naturally be expected that shorts
and bran from the more efficient mills would contain less flour, since the
production of flour is the object of milling wheat.
The fact that bran from the smaller, less efficient mills contains con-
siderable flour and endosperm particles brought up a very interesting
question in connection with the matter of ground bran in shorts. It was
found that several concerns which do not mill wheat were putting shorts
on the market. After the press notice, previousty mentioned, was issued
representatives of these concerns came to the Bureau of Chemistry to
find out where they stood. They put up a very plausible argument.
They claimed that they were buying bran from the smaller, less efficient
mills which contained a considerable amount of shorts material and
they were merely doing to it that which the larger, efficient mills do to
the bran in their regular process; that is, subjecting it to more attrition
with the result that they were actually producing shorts. There seemed
to be something in their argument and they submitted some samples
74 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. f
which seemed to pass the test for shorts. However, when the Bureau of
Chemistry picked up samples of the products of these concerns they did
not pass the test. They were not doing what they claimed; that is, sub-
jecting the bran from the smaller mills to the same treatment that it
receives at the larger mills, but were actually grinding the bran. The
Bureau of Chemistry conducted a vigorous campaign against the practice
of grinding bran to make shorts, with the result that it is having very
little difficulty along these lines at present. It might be of interest to
say that the inspectors found Williams or Greundler grinders in a good
many flour mills inspected but in most cases they had rot been installed.
It is not known whether the millers had taken their cue from the item in
the Community Miller or whether the Community Miller got the idea
from the fact that some mills were doing it but probably the latter is
the case; at any rate, the activity of the Bureau of Chemistry seemed to
have discouraged the practice so that they did not install the grinders.
The method developed by Bisbee, page 75, is entirely different from
the one just described. However, the reports on a large number of samples
examined by the two different methods and reported independently agreed
surprisingly well.
THE DETECTION OF THE ADULTERATION OF SHORTS.
By D. B. Bispes (U.S. Food and Drug Inspection Station, U. S. Custom
House, St. Louis, Mo.).
Shorts is a term applied to a mixture of particles of bran, germ and
endosperm, all derived from wheat during its milling into flour. As
frequently marketed, shorts contain low-grade flour and particles of
ground weed seeds and other screenings.
Attention is called to the following important factors in the detection
of the adulteration of shorts:
(1) Shorts are produced only by flour mills. Any mill producing shorts
and not flour is producing false shorts.
(2) In a flour mill, the bran is tailed off over a wire screen of 18 to 22
mesh. A very few mills use a finer screen, some as fine as 32 mesh. It is
admitted by all millers that an 18-mesh screen is as coarse as can be used.
All particles in true shorts are, therefore, not above 18 mesh in size.
(3) The better and more complete the separating machinery in a mill,
the more complete the recovery of flour and the ‘‘leaner’’ the shorts.
A small mill (1000 barrel or less daily capacity) lacking the extensive
and expensive separating machinery which is found in a very large mill,
produces the richer shorts.
(4) The large mills usually market three grades of shorts—brown,
white and gray. Some mills separate the germ, not selling it as a part of
1921] BISBEE: DETECTION OF THE ADULTERATION OF SHORTS 75
the shorts; other mills separate a part of the coarse middlings, as they
are passing through the mill, selling this separated part as breakfast food.
(5) As a corollary to (3) and (4), it must be remembered that the
brown shorts produced by a very large mill, such as the Pillsbury mill,
may be so completely freed from germ and endosperm particles that in
nearly all respects it resembles a reground bran.
From these five facts, it is seen that it is necessary to know the source
of a lot of shorts before accurate judgment can be passed upon it. Is this
source a flour mill? If so, what is its daily capacity? Does it market more
than one grade of shorts? Are the middlings streams scalped to produce
breakfast food or other by-products? With correct answers to these
questions and with data obtained as described below an accurate judg-
ment may be formed as to whether a sample of shorts has been adulter-
ated.
The writer has recognized the following as adulterants of shorts:
(1) Coarse bran; (2) reground bran; (38) ground rice hulls; and (4),
flour (if this he termed an adulterant). He has found, substituted entirely
for shorts: (1) Reground bran with ground screenings; and (2), a mix-
ture of reground bran and flour. The writer first separates the sample of
shorts into portions by means of wire screens of 40, 60 and 100 mesh.
If it is evident that the sample contains coarse bran, a 20-mesh screen
is first used. The sample is thus divided into what is termed the 20-mesh
portion (that part retained on a 20-mesh wire screen), the 40-mesh
portion, the 60-mesh portion, the 100-mesh portion, and the fines. Ash
is then determined in the original sample. Fiber is determined in the
original sample and in each portion except the fines. Each portion is
examined with a strong hand lens, magnifying ten times. With these
data and with the necessary information as to the producing mill, the
purity of the product may be judged.
The ash in bran is 6 per cent or more; in shorts, from 5.5
down to as low as 2 per cent, depending upon the grade; the richer the
shorts, the lower the ash. Fiber in bran will run about 11 per cent; in all
true shorts examined—save the Pillsbury and the Washburn-Crosby
brown shorts—fiber did not exceed 8.5 per cent, usually running less
than 8 per cent; the richer the shorts the lower the fiber. The fiber in
the various portions obtained by screening will vary with the proportion
of bran particles.
The examination of the various portions by means of a strong lens
will reveal the ingredients of these portions. The 20-mesh portion is
entirely bran. If a true shorts is under examination, the 40-mesh portion
is almost entirely bran, but contains a few germ and endosperm particles.
The 60-mesh portion is chiefly bran, but contains very many germ and
endosperm particles. The 100-mesh portion consists of germ and endo-
76 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
sperm particles with considerable bran. The fines contains some fine bran
particles, but is almost entirely endosperm particles.
How do the various adulterants affect these analytical results?
Coarse bran is entirely separated in the 20-mesh portion and is easily
recognized. It raises the ash and fiber content of the original sample.
Reground bran raises the ash and fiber content of the original sample
and of each portion. If reground bran has been entirely substituted for
shorts, each portion will be seen to consist almost solely of bran particles
and will have a fiber content of 9 to 11 per cent. As some of the endosperm
always adheres to the bran (more to soft wheat bran than to hard wheat
bran), and as this endosperm material is separated from the bran and
partly pulverized when the bran is reground, the 60- and 100-mesh por-
tions and the fines will contain a small proportion of endosperm particles.
A mixture of reground bran and flour will have a fiber and ash content
normal to true shorts, but the screens at once reveal this form of adul-
teration, as all of the flour passes all screens and can be recognized easily
in the fines, while the various portions are seen to be similar to the por-
tions obtained by screening a reground bran.
Ground rice hulls are very high in fiber and ash. The original sample
and the various portions will be found to contain startling amounts of
fiber. In the 40-mesh portion of one sample the writer found 17 per cent
of fiber. Rice hulls are easily recognized by decanting the light bran
fiber from the heavy rice hull fiber (after the alkaline fiber digestion),
the rice hull particles retaining their form and characteristic surface
markings and having a lemon color.
When weed seeds are ground into shorts, their seed coats will be recog-
nized by the eye. The particles of their endosperms will be seen in the
60- and 100-mesh portions and allowance must be made for them in
judging the shorts, as they lower the fiber and ash in proportion to their
amount.
Flour, when mixed with shorts, lowers the ash and fiber of the original
sample, but has no effect upon the various portions, as it passes all
screens. It may be recognized in the fines by the lens and by its smooth,
slick feeling.
Before passing judgment upon shorts samples, the analyst should
obtain many samples of true shorts of various grades and also several
samples of known adulterated shorts. These known samples should be
examined together with and in comparison with the shorts under investi-
gation.
It is particularly true with this method that experience is necessary
before the analyst can feel confidence in his judgment. Should there be
any doubt in his mind, an inspection of the producing mill should be
made and known authentic samples of its shorts examined in comparison
with the suspected sample.
1921] SILBERBERG: REPORT ON STOCK FEED ADULTERATION CAE
REPORT ON STOCK FEED ADULTERATION.
By B. H. Sitpersere (Bureau of Chemistry, Washington, D. C.), As-
sociate Referee.
Since the question of the quantitative determination of ingredients
of mixed feeds still appears to he a live one, it was assumed that it would
be of interest to continue the work along this line, confining it to a mix-
ture of two ingredients only. Many feeds, particularly by-product feeds,
are in themselves rather complex, containing two or more ingredients;
e. g., hominy feed contains corn bran, corn starch, some horny endosperm
of the corn and, if properly made, corn germ or corn germ meal; also oat
feed contains oat hulls, oat bran tissues and oat starch. Commercial rice
branis another such by-product feed containing normally rice bran tissues,
more or less broken rice which appears microscopically as starch, and not
more than 10 per cent of rice hulls. The commonest form of adulteration
of rice bran is an excess of rice hulls. Your associate referee devised a
method for the quantitative determination of rice hulls in rice bran.
This method gave results which correlated so closely with those obtained
chemically, that your associate referee thought it timely to submit the
method to the collaborators. The method is as follows:
Thoroughly mix the sample to be examined. Draw out a small portion and grind
until it all passes through a 60-mesh sieve. Weigh 4 mg. on a slide ruled in parallel
lines ;\; inch apart, or transfer to the ruled slide after weighing. Add just sufficient
chloral hydrate solution (1 to 1) to fill in under the cover glass, which should be prefer-
ably square (about 22 mm.). After the cover glass is in place warm gently, but do
not boil. This is to eliminate the starch masses and clear the tissues.
Use a magnification of about 90 diameters (6 compensating ocular and 16 mm. apo-
chromatic objective). Count the particles of hull tissue. The high refraction and yellow-
ish green color of the hull particles will aid in distinguishing the small pieces in which
the structure is not easily recognizable. In order to avoid duplicate counting, it is
well to disregard those particles which extend over the upper line of the strip.
From results obtained on standards containing known amounts of hulls, the approxi-
mate amount of hulls present in the sample can be estimated.
The collaborators received four reference samples of rice bran con-
taining 10, 15, 20 and 25 per cent respectively of rice hulls, a sample of
ground rice bran free from hulls, one of ground fice hulls, two samples,
A and B, containing percentages of rice hulls known only to the associate
referee, and a ruled slide to be used in making counts. They were advised
to familiarize themselves with the microscopic appearance of rice hulls
and rice bran, and then to count at least two, preferably four or five
slides, of each standard or reference sample and of each unknown. The
system of counting each standard twice, each unknown twice, and then
repeating the count on the standard nearest to the unknown, was recom-
mended; also that this operation be repeated before making a report.
78 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
It was requested that all counts be reported, on standards as well as
unknowns, with conclusions as to the amount of hulls in the unknowns.
This was complied with in all but two cases in which no data were given
except the conclusions, making it impossible to investigate the reason
for the results being so far from correct in one of these cases. It was
stated in this instance that the analyst was somewhat inexperienced in
microscopic work, although this same statement was made in the case of
another analyst whose results were correct within 0.1 and 0.2 per cent.
The counts obtained by most of the collaborators on the reference
samples indicate that only the particles of epidermal tissue were counted
instead of all the particles of hull as directed. But the counts thus ob-
tained appear to be so consistent and the results so good it seems advisable
to use the number of epidermal particles rather than all the hull particles
as a factor and change the method to read ‘‘Count the particles of epi-
dermal tissue of the hull’’ instead of ‘‘ Count the particles of hull tissue’’.
RECOMMENDATION.
The results as shown in the table, meagre as they are, appear to be of
such character as to warrant the recommendation that the method be
adopted as a tentative method for the quantitative microscopic deter-
mination of rice hulls in rice bran, and that it be made the subject of
further study.
Counts obtained on standards and unknowns.
AVERAGE COUNTS ON STANDARDS REPORTS ON UNKNOWNS
Sample A 12 per cent Sample B 18 per cent
ANALYST 10 15 20 25
per cent/per cent|per cent/per cent Average Reported Average Reed
count count
per cent per cent
1 103 162 196 oor 127 12.2 185 17.9
2 eae cE tx uae ar53 20.0 ahi 24.2
3 97 142 180 220 101 10 147 15
4 92 162 202 251 134 13.3 173 17.1
5 195 288 386 514 271 13-14 437 22
6 226 | 325 | 397 | 554 Aoi etaie Boe tee
7 550 ifn: sete ae 10+ oaks 15+
REPORT ON SACCHARINE PRODUCTS.
By H. S. Paine (Bureau of Chemistry, Washington, D. C.), Referee.
On account of delay in being advised of his appointment, the Referee
on Saccharine Products is unable to report any progress with respect to
work actually accomplished. Associate referees have been appointed on
1921] PAINE: REPORT ON SACCHARINE PRODUCTS 79
the following subjects: sugar-house products; honey; and maltose prod-
ucts. J. F. Snell was unable to serve again as Associate Referee on Maple
Products and, in view of the short time remaining before the meeting of
this association, it was impossible to secure any one to succeed him. Be-
cause of the impossibility of doing any work in the time available, each
associate referee was requested to present to the association at this meet-
ing a tentative program of work for the coming year. If work is started
immediately on the programs outlined it should be possible to secure
resulis of value during 1921 and the remainder of 1920.
No report on honey was made by the associate referee.
No associate referee on maple products was appointed and no special
report on this subject was presented.
No report on maltose products was made by the associate referee.
No report on sugar-house products was made by the associate referee.
The appointment of the following committees was announced by the
president:
Committee on auditing: A. J. Patten of Michigan and H. H. Hanson
of Delaware.
Committee on nominations: R. N. Brackett of South Carolina, C. H.
Jones of Vermont and W. W. Skinner of Washington, D. C.
Committee on resolutions: William Frear of Pennsylvania, Julius
Hortvet of Minnesota and E. W. Magruder of Virginia.
Committee to wail upon the Secretary of Agriculture: B. B. Ross of Ala-
bama and C. H. Jones of Vermont.
Committee to wait upon the Honorary President: W. F. Hand of Mis-
sissippi and A. J. Patten of Michigan.
The meeting adjourned at 1 p. m. to reconvene at 2 p. m.
FIRST DAY.
MONDAY—AFTERNOON SESSION.
REPORT ON FERTILIZERS.
By R. N. Brackett (Clemson Agricultural College, Clemson College,
S. C.), Referee.
Upon my belated arrival at the 1919 meeting of the association, I
found that in addition to the General Referee on Fertilizers, the associa-
tion had appointed the usual associate referees.
I persuaded W. H. Ross to act as Chief Associate Referee on Borax,
on account of the work which he had already done on this subject and
because I felt that he would take a special interest in the work. In ad-
dition, I appointed R. B. Deemer, G. F. Lipscomb and C. A. Butt to
serve as associate referees in working out a method or methods of deter-
mining borax in fertilizers and fertilizer materials.
Only two new subjects have been brought up for investigation this
year: the working out of a suitable method for the determination of
borax in fertilizers and fertilizer materials; and a special study of a suit-
able method for the analysis of precipitated superphosphate. There has
been quite a considerable amount of work done upon the former and a
lively interest taken in the investigation. The following methods have
been suggested and worked out with considerable care:
Qualitative methods—Methods by Richardson, Pope and Ross, and
Rudnick, all involving the use of turmeric or curcumin. It has been sug-
gested that these methods, to some extent at least, may be used quantita-
tively.
Quantitative methods.—(1) Distillation methods by Richardson, Bartlett,
and Carpenter and Magruder and Breckenridge. (2) Methods without
distillation by Ross-Deemer, Lipscomb-Inman-Watkins, and by Jones
of Vermont. Some of these methods were published! in order that they
might be tried out by as many analysts as possible before this meeting.
REPORT ON THE DETERMINATION OF BORAX IN
FERTILIZERS AND FERTILIZER MATERIALS.
By Wituiam H. Ross (Bureau of Soils, Washington, D. C.), Associate
Referee.
The different methods that have been proposed for the determination
of borax may be classed conveniently into two groups as represented by
1 Am. Fertilizer, 1919, 51: (No. 13), 66; Ibid., 1920, 52: (No. 5), 57.
80
1921] ROSS: REPORT ON BORAX IN FERTILIZERS 81
the Gladding! and the Thompson? methods. In the methods of the first
group the boric acid is separated from the constituents with which it is
associated by distilling with methyl alcohol, and then determined in
the distillate in which it is recovered by titrating with standard alkali
solution. In the methods of the second group, the principle of the pro-
cedure is reversed. The boric acid is not volatilized but the interfering
substances are removed instead by precipitation and the boric acid in
the final filtrate is then determined by titration in the usual way.
When the necessity arose for determining small amounts of borax
in mixed fertilizers it was found that the volatile and soluble organic
constituents in fertilizers so interfered with the determination of the
borax that no satisfactory results could be obtained when following the
directions as outlined in the methods of either group. A number of
modifications were accordingly suggested by different workers in this
field, and the purpose of the present report is to give a summary of the
results obtained in a comparative study of the relative merits of three
of these modified methods which were selected as representative of those
which have come to our attention. These methods were developed in
the chemical laboratories of Clemson College, the Bureau of Soils and
Swift and Co. For convenience they are designated as the Lipscomb-
Inman-Watkins?, the Ross-Deemer‘ and the Richardson distillation
methods.
PREPARATION OF SAMPLES FOR COLLABORATIVE WORK.
The samples submitted to the different collaborators consisted of
four mixed fertilizer samples and three of potash salts. Sample No. 1
was a 5-10-0 fertilizer kindly supplied by J. E. Breckenridge of the
American Agricultural Chemical Co. and supposedly borax-free. All
qualitative tests indicated that the borax present, if any, did not exceed
0.01 per cent, and no borax was added. Sample No. 2 was the same as
No. 1 with sufficient borax and potassium chloride added to approximate
a 5-10-3 fertilizer containing 0.10 per cent of borax. Sample No. 3 was a
5-8-5 fertilizer prepared in the Department of Agriculture from cotton-
seed meal, tankage, cyanamide, ammonium sulfate, acid phosphate,
potassium chloride, sand and sufficient borax to make 0.10 per cent.
Sample No. 4 was the same as No. 3 with 0.75 per cent of borax added.
Sample No. 5 was a Chilean nitrate of potash containing an unknown
amount of borax. The results obtained by the writer in the analysis of
this sample varied from 0.71 to 0.73 per cent. Sample No. 6 was the
same as No. 5 with sufficient potash alum added to reduce the borax
content to 0.64 per cent, assuming it to be originally 0.72 per cent. Borax
1J. Am. Chem. Soc., 1898, 20: 288.
3 J. Soc. Chem. Ind., 1893, 12: 432.
3 Am. Fertilizer, 1920, 52: (No. 5), 57.
4 Ibid., (No. 6), 62.
82 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, Vo. 1
was also added to the extent of 0.75 per cent of the final mixture, making
a total of 1.39 per cent. Sample No. 6 was a mixture of potassium chloride,
sodium carbonate and potassium phosphate with sufficient borax to
amount to 1.00 per cent of the mixture.
The borax used was prepared by adding a known amount of boric
acid of a high degree of purity to a solution of an equivalent amount
of pure sodium carbonate. The solution was then evaporated on a water
bath, dried at 105°C., weighed and ground to pass a 175-mesh sieve.
Knowing the weight of the boric acid taken and of the product finally
obtained, it could then be calculated how much of the product would
have to be added to a fertilizer to give a boron content equivalent to
any desired percentage of anhydrous borax. The mixed fertilizer samples
were ground to 40 mesh and the mineral salts to 100 mesh. Uniform
distribution of the borax through each sample was insured by thorough
mixing in a mixing machine.
INSTRUCTIONS TO COLLABORATORS.
A detailed account of each method was forwarded with the samples
to each collaborator, and it was requested that each analyst submit a
report on completing the analysis indicating the method which in his
judgment gave most accurate results and which was considered most
rapid if applied in routine analysis. No indication was given of the com-
position of the samples other than that four were of mixed fertilizers
and three of potash salts.
Directions were also submitted for carrying out two qualitative tests
for borax which it was suggested might be applied quantitatively in the
case of the mixed fertilizer samples low in borax. These methods which
are designated the Richardson, and the Pope-Ross! qualitative methods
are modifications of the well-known turmeric paper and the tincture of
turmeric tests. The results reported are summarized in Tables 1 and 2.
1 Am. Fertilizer, 1920, 52: (No. 6), 65.
83
REPORT ON BORAX IN FERTILIZERS
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84 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
TABLE 2.
Deteclion of borax in mized fertilizers.
BORAX ESTIMATED BY TEST
ANALYST Sample No. 1 * Sample No. 2 t Sample No. 3t
Richardson | Pope-Ross | Richardson | Pope-Ross | Richardson | Pope-Ross
per cent per cent per cent per cent per cent per cent
A: Ben pn ec none none |more than] less than |more than} less than
0.05 0.10 0.05 0.10
GyAs Butte sea none none less than | less than | less than | less than
0.10 0.10 0.10 0.10
G. J. Kuhlman, jr....| trace trace less than
0.10 0.10 0.10 0.10
H. R. Laub and R. M.
Jonestte. see nati present 0.10 present 0.10 present 0.10
* No borax present.
t Borax present, 0.10 per cent.
COMMENTS BY COLLABORATORS.
C. A. Bult——The Ross-Deemer method is most suited as regards both accuracy and
speed for mixed fertilizers and mineral salts. The Lipscomb-Inman-Watkins
method gives solutions which are more difficult to boil, due to bumping, and which
filter much more slowly than by the Ross-Deemer method. The accuracy of the
former method is impaired by the fact that an aliquot corresponding to only 1 gram
of sample is recommended. In the Richardson distillation method, water-insoluble
borates are likely to be formed on the addition of alkalies to mixed fertilizers and
evaporation to dryness. Following this method as outlined and taking up with water
after igniting, only a portion of the borax is obtained.
The Pope-Ross qualitative method was found to be much more rapid than the
Richardson method and due to inability to secure all of the borax in solution by the
latter method, as mentioned in the criticism of the distillation method, the Pope-Ross
method is regarded as more accurate. This method gave results that enabled us to
easily distinguish between materials containing more or less than 0.10 per cent.
G. J. Kuhlman, jr—The Richardson qualitative method requires less cost, less work,
and can stand overnight réady for the next day. The Pope-Ross qualitative method
is costly but accurate. The Richardson quantitative distillation method requires too
much care and borax is liable to be lost during the process of manipulation.
H. R. Laub and R. M. Jones —The Ross-Deemer method is the best although not
quite so fast as the Richardson distillation method which, however, gives low results.
L. H. Crudden.—The limewater is not so effective for precipitating the sulfates and
phosphates as the barium chloride; this explains the fact that Samples Nos. 1, 2 and
3 with a low per cent of borax gave higher results with the Lipscomb method than
with the Ross-Deemer method, the end point being somewhat indefinite in the former
method.
W. J. Gascoyne-—The Ross-Deemer method is the only method by which satisfactory
results could be obtained.
1921] ROSS: REPORT ON BORAX IN FERTILIZERS 85
DISCUSSION.
Reports have been received from eight collaborators. Four of these
reports gave results with the Richardson distillation method; seven with
the Lipscomb-Inman-Watkins method; and all eight with the Ross-
Deemer method. So far as known, six of the collaborators had no previous
experience with any of the methods. Five out of the six placed the Ross-
Deemer method first as regards accuracy and one made no comment.
Four out of the six also placed this method first as regards rapidity; one
placed the Richardson distillation method first as regards rapidity but
_the results which this collaborator reported by this method were too low;
and one made no comment. The remaining two collaborators reported
most favorably on the respective methods with which they were most
familiar but good results were also reported by the Ross-Deemer method
and one of these collaborators placed this method first when phosphates
are absent.
The reports. show that borax in fertilizers, even when present in
relatively small amounts, can be determined with a high degree of accu-
racy by all three methods in the hands of experienced analysts. The col-
laborators who had no previous experience with the Richardson distil-
lation method as a rule reported low results with this method, while high
and low results were reported with the precipitation methods.
Since this work was completed, a modification of the distillation method
has been proposed by J. M. Bartlett of the Maine Agricultural Experi-
ment Station and it is possible that this method may prove superior to
any of the others in the analysis of certain classes of materials as, for
example, those which are high in soluble phosphates and low in borax
and which are, therefore, most difficult to handle by the precipitation
methods.
Reports on the qualitative methods were received from four of the
collaborators. One made no comments on either method; three placed
the Pope-Ross test first as regards accuracy; two also placed this test
first as regards rapidity; and one considered the Richardson test more
rapid.
RECOMMENDATIONS.
It is reeommended— <
(1) That the Ross-Deemer method for the determination of borax
in fertilizer materials and mixed fertilizers be adopted as a tentative
method.
(2) That further work be done on the comparison of the proposed
tentative method with the distillation method of Bartlett.
(3) That substances other than fertilizer materials be included in the
study of these methods.
86 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
REPORT ON BORAX IN MIXED FERTILIZERS.
By R. B. Deemer (Soil-Fertility Investigations, Washington, D. C.),
Associate Referee.
Previous to the work upon the method which has been proposed as
tentative for the determination of borax in mixed fertilizers, many
attempts were made to use the distillation method developed by Chapin’.
The results which were first obtained were very unsatisfactory as con-
siderable difficulty was experienced in determining the point at which
the volatilization of methyl borate was complete. Even after the dis-
tillation of as many as 400 ce. of alcohol, titrations of a few tenths of a
cc. of 0.1N alkali were obtained. In these first trials from 5 to 10 cc. of
concentrated hydrochloric acid were used in acidifying the sample to
liberate the boric acid, and it was not until later that the publication of
Allen and Zies? was reviewed. They observed that arsenic in the presence
of more than a slight excess of acid is volatilized with the methyl borate
and later obscures the end point when the boric acid is titrated. This
suggested the use of a smaller amount of acid and, when a slight excess
of acid of known amount was tried, more concordant results were ob-
tained. Owing to the pressure of other work, the cause of this difficulty
experienced with mixed fertilizers has not been investigated. However,
it was further found necessary to introduce a modification of the treat-
ment of the distillate, after the removal of the alcohol, before entirely
satisfactory results were forthcoming.
The results reported by the previous investigators of this method were
obtained upon much larger quantities of boric acid and boric oxide than
are at present important to the association. It was thought, therefore,
that results with smaller amounts of boron, and a few suggestions upon
the method, might prove of interest. Chapin’s article should be consulted
for full details of manipulation and a discussion of the more important
points of the reaction involved. The investigation reported by Allen
and Zies is a very complete study of Chapin’s method and contains
excellent data which definitely clear up many of the points raised by
him, which adds materially to the value of themethod. In order to make
the modifications and suggestions clear the following brief outline of the
method is given:
METHOD.
Two grams of the sample are placed in a 150 cc. side-neck distillation flask (which
is referred to as the ‘decomposition flask”), 8 cc. of water are then added, followed by
1 cc. of concentrated hydrochloric acid and 15 grams of granular, anhydrous calcium
chloride. The distillation of the methyl alcohol is started and continued until about
1 J. Am. Chem. Soc., 1908, 30: 1691.
2 J, Am. Ceram. Soc., 1918, 1: 739.
1921] DEEMER : REPORT ON BORAX IN MIXED FERTILIZERS 87
10 cc. have condensed in the decomposition flask, after which the latter is heated just
enough to prevent further condensation. Distillation is continued until 150 cc. of
the distillate are collected to which are now added approximately 30 cc. of 0.1N sodium
hydroxide and the alcohol recovered by distillation. Ten cc. of a 10% solution of
barium chloride and a few crystals of barium hydroxide are added and the solution
boiled a short time to remove the last traces of methyl alcohol. The precipitate which
forms is filtered off and to the filtrate is added 2-3 drops of methyl red and the
solution made acid with a very slight excess of 0.5N hydrochloric acid. Carbon dioxide
is then removed in the manner suggested by Chapin, and the titration of the boric
acid made with 0.05N sodium hydroxide in the usual way.
DISCUSSION.
In place of the Erlenmeyer flask which Chapin suggests it was found
more convenient to use a wide-neck, 250 cc. flask for a receiver, and also
to omit the water bath for heating the decomposition flask, using a
direct flame instead. The adjustment of the heat applied to this flask
is essential as it should not be such as to cause a reduction in the volume
of its contents as the volatilization of the methyl borate should be accom-
plished by the vapors of methyl alcohol from the large distillation flask.
If the apparatus is set up in a vertical position and a short spiral con-
denser substituted for the one suggested in the original method, a more
satisfactory arrangement of the various parts may be made.
The composition of the precipitate formed by the addition of barium
chloride to the distillate has not been investigated; however, unless this
procedure is followed it is necessary, after removal of the alcohol, to
evaporate the solution to dryness and ignite the residue. Chapin’s
discussion of the end points should be noted in particular as these are
never so sharp in this method as those which are obtained in the one
proposed as tentative. When neutralizing with sodium hydroxide it will
be noted that the red color of the methyl red fades very gradually and
it is essential that the full bright yellow of this indicator should he pro-
duced at this point. The brownish tinge noted by Chapin in the final
titration marks the end of the reaction in the presence of the two indi-
cators. In this connection it is well to remember that the volume of the
solution should be below 100 cc. and, in fact, better end points can be
obtained with a volume of from 50 to 75 ec. The work of Kahlenberg
and Schreiner! explains very clearly the reason for this. A blank should
be run upon the reagents and the amount of hydrochloric acid required
to neutralize the calcium chloride should be determined, as well as that
required to acidify the quantity of the fertilizer sample taken for the
determination. It will be necessary if the reagents are used in proportions
other than the amounts suggested, to determine the effect of any such
changes. In this work a blank of 0.35 ec. of 0.05N sodium hydroxide was
obtained which,it will be noted, agrees with that found by Allen and Zies,
1Z. physik. Chem., 1896, 20: 547.
88 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
who have shown by very careful work that it is not due to boron in the
glass of the apparatus.
SAMPLES.
The samples used in testing the method are those sent out by W. H.
Ross to the collaborators this year, and the results obtained are as
follows:
TABLE 1.
Borax in mized fertilizers.
ANHYDROUS BORAX
SAMPLE NUMBER
Found
per cent per cent
1 0.03 0.00
2 0.10 0.10
3 0.11 0.10
4 0.74 0.75
To further test this method, varying amounts of a solution containing
a known amount of carefully recrystallized boric acid were added to 2
grams of the sample in the decomposition flask. The above Sample No.1
was used and the results reported are corrected for the amount of anhy-
drous borax previously found.
TABLE 2.
Recovery of known amounts of boric acid.
ANHYDROUS BORAX
Added Found
per cent per cent
0.05 0.05
0.10 : 0.10
0.15 0.14
0.20 0.20
No report was -presented by G. F. Lipscomb, one of the associate
referees on borax in fertilizers.
THE DISTILLATION METHOD FOR THE ESTIMATION OF
BORAX IN MIXED FERTILIZERS.
By J. M. Bartrerr (Agricultural Experiment Station, Orono, Me.).
As most members of this association know, the summer of 1919 was
a notable one for both users and manufacturers of fertilizers on account
1921] BARTLETT: BORAX IN MIXED FERTILIZERS 89
of the discovery that borax was present in some brands of mixed goods
in sufficient quantity to be injurious to plants. Many complaints were
received at the Maine Agricultural Experiment Station from farmers in
Aroostook County that some fields of potatoes were not making normal
growth and an investigation revealed the possibility that the brands
of fertilizer on which they were planted carried considerable borax.
Consequently, as many samples of the fertilizers used in the affected
area as could be found were collected and sent to the Agricultural Ex-
periment Station with the request that their borax content be determined
as soon as possible. It was also considered desirable that the samples
collected in the spring inspection be tested for borax. This increased
the number of samples to about three hundred.
Since there is no official method for this determination, the writer was
obliged to try out the various methods for the estimation of boron in
other materials and test their applicability to mixed fertilizers. The
Gladding and Thompson methods for the determination of borax in
foods and food preservatives! seemed to promise well for the purpose
and were tried first. In the Thompson method the material is first
ignited with caustic soda to free it from organic matter, taken up with
dilute hydrochloric acid and treated with calcium chloride, sodium hy-
droxide and limewater to remove phosphates, then filtered and the
filtrate made acid to free the boric acid, which is titrated with 0.1N
sodium hydroxide, using phenolphthalein as indicator after making the
solution neutral to methyl orange and adding a neutral solution of
glycerol. This method was quite simple to operate but, when tried on
a fertilizer carrying a large amount of soluble phosphates and organic
matter, it gave low results when known amounts of borax were added.
The Gladding method for the determination of borax in commercial
preservatives, which is based on the fact that boric acid readily distils
over with methyl alcohol vapor, was next tried. A very good grade of
methyl alcohol was obtained which gave a blank of only 0.6 cc. of 0.1N
sodium hydroxide on 10 cc. when distilled with the other reagents used,
and when tried on several borax-free fertilizers, with known amounts of
boric acid added, gave very satisfactory results. The boric acid was
titrated in the alcohol distillate as directed in the Gladding method.
Consequently, the whole operation required only 35 or 40 minutes and
with two sets of stills one man could make fifteen to twenty determina-
tions a day. The method was accurate to one or two tenths of a per cent
and, as almost all fertilizers examined at that time, showing any borax by
the qualitative test, contained from 0.3 to over 2 per cent it was suffi-
ciently accurate for the writer’s purpose and very rapid. Later on, how-
ever, the Bureau of Soils advised that a mixed fertilizer could not safely
carry over 2 pounds (0.1 per cent) of anhydrous borax to the ton. Trials
1A. E. Leach. Food Inspection and Analysis. 4th ed., 1920, 884, 886.
90 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
made with fertilizers free from borax showed that some substances,
acid to phenolphthalein, were volatilized with the alcohol which must be
removed before the boric acid can be accurately titrated. It became nec-
essary to modify the method so one could estimate hundredths instead
of tenths of a per cent. The method now employed is given in detail
below and, in the writer’s laboratory, has proved to be accurate either
with small or quite large amounts of borax. Late in the fall of 1919, the
Bureau of Soils sent out a method developed in that laboratory which
is somewhat similar to the Thompson method except that barium in-
stead of calcium salts are used to separate phosphates from the boron.
The method as applied to mixed fertilizers low in borax content is longer
than the distillation method, and attempts have been made by some
chemists, notably C. H. Jones of the Vermont Agricultural Experi-
ment Station, to shorten it. The writer has not been able to recover
as much of the borax by this method, or by other similar methods, as
by the distillation method. Barium produces a heavier precipitate than
calcium, inasmuch as it throws down all of the sulfuric acid present and
would seem to offer a greater opportunity for loss of boron by occlusion.
After spending much time in trying out the various methods and
modificatiors, both original and suggested, the writer prefers the Glad-
ding distillation method for goods with high phosphoric acid and low
boron content. It seems to be the most practical and accurate method
when volatile organic acids both in the fertilizers and alcohol are elimi-
nated. The method as conducted at the Maine Agricultural Experi-
ment Station is as follows:
APPARATUS.
The apparatus! consists of two 200 cc. round-bottomed flasks, a Liebig condenser,
and a 200 cc. Erlenmeyer receiving flask. One of the 200 cc. round-bottomed flasks,
No. 2, is supplied with a doubly perforated rubber stopper, through which passes a
glass tube running to the bottom of the flask. The other hole is supplied with a short
tube leading to the condenser. The other 200 cc. round-bottomed flask, No. 1, is
fitted with a perforated rubber stopper and a short bent tube connected with a rubber
tube leading to the long tube in Flask No. 2. The whole apparatus is supported
by clamps and rings on two stands.
DETERMINATION.
If the material to be examined is a mixed fertilizer or probably contains less than
2 per cent of anhydrous borax, weigh 5 grams into Flask No. 2. If the material is a
chemical containing much more than 2 per cent of borax, use 2 grams. Then add
5 ce. of 50% phosphoric acid and 20 cc. of methyl alcohol and connect the flask with
the condenser. Put 100 ec. of methyl alcohol in Flask No. 1, which is set in a water
bath and connected with Flask No. 2. Put the receiving flask in place at the end of
the condenser and apply sufficient heat to the water bath to keep a steady flow of bub-
bles of methyl alcohol passing through Flask No. 2. Some heat must also be applied
to Flask No. 2 to keep the volume at about 25 cc. The lamps once regulated need
1A. E. Leach. Food Inspection and Analysis. 4th ed., 1920, 884.
1921] BARTLETT: BORAX IN MIXED FERTILIZERS 91
very little attention and one person can easily run two distillations at once. Con-
tinue the distillation for about 30 minutes and distil 100 cc. When the distillation is
complete, add 2-3 drops of phenolphthalein to the distillate and 5-10 cc. of 0.1N
sodium hydroxide, or enough to give it a permanent pink color. Stopper the flask,
shake well and connect at once with a regular alcohol still, supplied with a Hopkins’
or similar bulb, distil off the alcohol and save for another determination. A water
bath and not a lamp flame should be used for this purpose.
Leave the residue, which should be not less than 10 cc., in the flask, transfer to a
platinum or porcelain dish, using as little water as possible, and evaporate to dryness
on a steam or water bath. When dry, ignite below redness. Then acidify with a few
drops of N hydrochloric acid, add 20-25 cc. of water and warm for 1-2 minutes on
the steam bath; filter into a small flask, thoroughly wash and make up to about 50-75
cc., attach to an air-cooled condenser and gently boil for a few minutes to remove
carbon dioxide. Add 3-4 drops of methyl red and 0.1N sodium hydroxide until the
red color just disappears. Add about 1 gram of mannite, or less if but a small amount
of boron is present. At this point if boric acid is present the solution will take on a
pinkish color, the depth of color depending on the amount present, usually 0.01 or
0.02 per cent is sufficient to give the reaction if the solution has been carefully neutral-
ized with the sodium hydroxide solution. Then add 2-3 drops of phenolphtha-
lein and titrate the solution with standard 0.1N sodium hydroxide. A blank should be
run with the reagents but if sodium hydroxide is free from carbon dioxide the blank
should not be more than 0.2 cc. Recrystallized boric acid should be used to stand-
ardize the 0.1N sodium hydroxide.
The writer prefers the above method for the following reasons:
(1) The first distillation gives a more complete and clean separation
of the boron from the other materials in the fertilizer than the writer has
been able to obtain by any other method. There is no loss by occlusion
or incomplete washing of heavy precipitates.
(2) The boron can be separated more quickly by distillation with
methyl alcohol than by most of the precipitation methods and the actual
time required by the chemist is less as the stills when once started need
very little attention. With plenty of stills, many determinations can be
made in a day.
(3) The same amount of substance can be taken, whether the amount
of boron present is quite large or small.
(4) The blank from reagents is very small and not variable; if these
are free from carbon dioxide, the blank should not be more than 0.02
per cent. .
(5) Since only a small amount of sodium salts is present there is no
spattering and therefore no chance for loss when the residue is ignited.
92 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [YVol. V, No. 1
Results obtained on fertilizers of known and unknown boron content.
BORAX RECOVERED
FERTILIZER BORAX ADDED
Distillation method Ross-Deemer method
gram gram gram
5-10-0 0.005 0.0049 0.0031
0.025 0.0236 0.0186
0.050 0.0504 0.0390
0.100 0.0992 0.0820
5-8-0 0.010 0.0101 0.0078
0.005 0.0052 0.0040
4-8-0 0.100 0.1002 0.0895
0.050 0.0485 0.0440
3-10-4 0.100 0.0960 0.075*
0.100 0 0960 0.076*
0.050 0.0460 0.034*
0.050 0.0480 0.035*
0.010 0.0092 0.012*
No. 1 Unknown 0.0022 0.0019
No. 2 Unknown 0.0012 0.0009
No. 3 Unknown 0.0008 0.0007
No. 4 Unknown 0.0008 0.0006
No. 5 Unknown 0.0005 0.0003
No. 6 Unknown 0.0023 0.0018
No. 7 Unknown 0.0021 0.0014
* Made by Jones’ modification
THE COMPOSITION AND PREPARATION OF A NEUTRAL
SOLUTION OF AMMONIUM CITRATE?
By C.S. Rosrnson (Agricultural Experiment Station, E. Lansing, Mich.),
Associate Referee on the Preparation of Ammonium Citrate.
The following report is submitted in accordance with the recommenda-
tion approved by the association at its 1919 meeting? ‘‘that the referee
be instructed to determine the exact composition of a strictly neutral
solution of ammonium citrate and report at the next meeting of the
association with recommendation as to the preparation of such a solution”.
Prior to his notification of the above action by the association the
associate referee had taken up the investigation of this subject and had
prepared the results for publication’. Further details of the work dis-
cussed in the present report may be obtained from that publication.
THE COMPOSITION OF A STRICTLY NEUTRAL SOLUTION
OF AMMONIUM CITRATE.
From the very first proposal of the use of this reagent, there has existed
a confusion of the term ‘‘neutral’’, as applied to the solution itself and
1 Presented by R. N. Brackett.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 565.
8 Mich. Agr. Expt. Sta. Tech. Bull. 46: (1919).
1921] ROBINSON: NEUTRAL SOLUTION OF AMMONIUM CITRATE 93
to the salt. This was due to a failure to recognize the fact that, owing to
dissociation and hydrolysis, a solution of the ‘‘neutral’’, or better the
normal, salt of ammonia and citric acid is not neutral but alkaline, 7. e.,
the concentration of the hydroxyl ions exceeds that of the hydrogen ions.
Attempts have been made to fix the composition of a truly neutral
solution but without much success and as Hand has pointed out, ‘‘any
analytical method in a large measure leaves the question in its former -
condition, because we must first prepare the neutral solution before we
can ascertain the precise amounts of citric acid and of ammonia that will
reproduce it’”).
McCandless’, acting in accordance with instructions of the associa-
tion, attempted to determine the relation between the reaction and
composition of several solutions sent to him by testing them for neu-
trality to corallin and also determining the ratios of ammonia to citric
acid in them. Of nine solutions submitted, three proved to be neutral
to the indicator used. The ratios in these were respectively 1: 3.803,
1: 3.816 and 1: 3.808, giving an average of 1 to 3.809.
Of the solutions analyzed by McCandless, the three which were neutral
to corallin were actually very close to the point of absolute neutrality,
much closer, in fact, than the one which he selected as a standard. Here
again, however, is a case of the confusion of the two solutions, one neutral
itself in reaction and the other a solution of the neutral salt.
The development of the methods for determining the concentration
of hydrogen ions in solutions gave the first method for accurately prepar-
ing a truly neutral solution, the determination of whose composition
would serve for its reproduction. Using the colorimetric method outlined
below, but with some variations in technique, a number of such neutral
solutions was prepared and analyzed. The procedure used in their
preparation was as follows:
One hundred and ten gram portions of citric acid were weighed into
700 ce. flasks, each dissolved in 75 cc. of water and mixed with concen-
trated ammonia to bring the reaction to a pH of 6.6-6.8. For final
neutralization, each solution was transferred to a 500 cc. graduate,
diluted to a density of approximately 1.10 and mixed with equal quan-
tities of phenol red indicator. The same volume of standard buffer solu-
tion with a pH of 7.0 was placed in a similar graduate and mixed with the
same amount of indicator. To the citrate solutions 2. N ammonium
hydroxide was then added until the colors checked that of the standard
solution whose volume had heen equalized with distilled water. The
reaction was finally checked by removing a few cc. of the citrate solu-
tion, diluting and checking against some of the standard in the com-
parator. The neutralized solutions were then returned to the flasks and
1U.S. Bur. Chem. Bull. 132: (1910), 9.
2 Ibid., 122: (1908), 147.
94 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
their densities adjusted to 1.0900 + 0.0001 at 20° C. + 0.5 determined
with a pycnometer.
For analysis, 25 ec. samples were diluted to 250 cc. and 10 cc. portions
were used. The ammonia was estimated by the distillation method and
the citric acid by titration after the addition of formaldehyde, all deter-
minations being made in triplicate. The averages are given in the fol-
lowing table:
TABLE 1.
Analysis of ammonium citrate solutions.
‘i AMMONIA ANHYDROUS CITRIC ACID | RATIO OF AMMONIA TO
SOLUTION PER LITER PER LITER ANHYDROUS CITRIC ACID
grams grams
1 45.39 171.83 1:3.785
2 45.36 172.66 1:3.807
3 45.37 172.02 1:3.791
4 45.35 171.96 rego
5 44.90 171.06 1:3.809
6 45.39 171.70 1 :3.783
7 45.68 173.05 1:3.788
8* 45.20 171.70 1 :3.798
Average............ 45.33 172.00 1 :3.794
* Neutralized by ordinary technique.
While such differences may appear to be large, it should be stated
that the extreme readings for the whole series were 26.41 and 26.87 cc.
of 0.1N hydrochloric acid for the ammonia determinations and 26.72
and 27.03 cc. of 0.1N sodium hydroxide for the citric acid estimations.
A ‘‘neutral’’ solution of ammonium citrate may then be defined as one in
which the ratio of ammonia to anhydrous citric acid is 1 to 3.794. At 20° C.
such a solution containing 45.33 grams of ammonia and 172.00 grams
of anhydrous citric acid per liter will have a density of 1.09.
THE PREPARATION OF A STRICTLY NEUTRAL SOLUTION
OF AMMONIUM CITRATE.
In some biochemical work involving the determination of hydrogen
ion concentrations, the writer had occasion to make use of the methods
devised by Clark and Lubs! for the preparation of bacterial culture media.
It occurred to him that these methods could be applied equally well to
the control of ammonium citrate solutions as had already been done in
principle by Eastman and Hildebrand*. The only differences between
the method of the latter investigators and the one to be described are
1J. Bact., 1917, 2: 1.
°J. Ind. Eng. Chem., 1914, 6: 577.
1921] ROBINSON: NEUTRAL SOLUTION OF AMMONIUM CITRATE 95
in the indicator and the standard solutions used, changes which, how-
ever, seem to greatly increase the accuracy and ease of manipulation of
the process.
Both procedures are based upon the method for determining colori-
metrically the hydrogen ion concentration of a solution, i. e., the reac-
tions of solutions. In brief, this consists in preparing a series of solutions,
whose compositions fix their reactions which are originally determined
electrometrically, adding to definite quantities of these solutions equal
quantities of a suitable indicator and comparing with them the color
‘produced by an equal concentration of the same indicator in the solution
to be tested. The basis of the method is found in the fact that indicators
change color not abruptly but through a definite range of hydrogen ion
concentration and that the range of reaction through which the change
of color is observable differs for different indicators. Thus, by the proper
choice of indicators, any region of reaction from normal hydrogen ion
concentration to normal hydroxyl ion concentration may he studied.
The choice of indicator is governed by its availability, its effective
range and the vividness of its color change; the selection of the standard
buffer solutions by the ease with which they can be accurately dupli-
cated and their range of reaction.
For the preparation of a neutral solution, an indicator must be chosen
whose maximum color change occurs at approximately the neutral
point. In the recently developed sulfonphthalin series this point is in-
cluded in the range cf phenolsulfonphthalin or phenol red. Hence this
indicator was tested as a substitute for the less brilliant corralin and
cochineal.
It is proposed to use as a standard buffer solution one prepared from
potassium dihydregen phesphate and sodium hydroxide according to
Clark and Lubs. The complete series covers a range from pH 5.8 to pH
8.0 in steps cf 0.2. The following table shows the compositions of the
various mixtures, tcgeiher with their reactions in terms of pil’.
TABLE 2.
KH2PO,;—NaOH Mixtures.
5.8 50 cc. M/5 KH2PO, 3.72 cc. M/5 NaOlt Dilute to 200 ce.
6.0 50 ce. M/5 KH2PO, 5.70 cc. M/5 NaOH Dilute to 200 cc.
6.2 50 cc. M/5 KH2PO, 8.60 ec. M/5 NaOH Dilute to 200 cc.
6.4 50 cc. M/5 KH2PO, 12.60 cc. M/5 NaOH Dilute to 200 ce.
6.6 50 cc. M/5 KH2PO, 17.80 cc. M/5 NaOH Dilute to 200 ce.
6.8 50 cc. M/5 KH2PO, 23.65 cc. M/5 NaOH Dilute to 200 ce.
7.0 50 cc. M/5 KH2PO, 29.63 cc. M/5 NaOH Dilute to 200 ce.
dee 50 cc. M/5 KH2PO, 35.00 cc. M/5 NaOH Dilute to 200 ce.
7.4 50 ce. M/5 KH2PO, 39.50 cc. M/5 NaOH Dilute to 200 cc.
7.6 50 cc. M/5 KH2PO, 42.80 ce. M/5 NaOH Dilute to 200 ce.
7.8 50 cc. M/5 KH2PO, 45.20 cc. M/5 NaOH Dilute to 200 ce.
8.0 50 cc. M/5 KH2PO, 46.80 ce. M/5 NaOH Dilute to 200 cc.
1J. Bact., 1917, 2: 26.
96 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Unless some means of checking the first solutions made from it are
accessible, the potassium dihydrogen phosphate should be recrystallized
four or five times. This product may then be kept as a special reagent for
future use and the solutions made from it by carefully weighing out the
desired quantities.
The sodium hydroxide solution is prepared from carbonate-free ma-
terial and standardized in the usual manner. It should be kept in a
paraffined bottle and protected from the carbon dioxide of the air.
From these stock reagents solutions may be prepared repeatedly
having reactions so constant that no difference in color can be detected
between lots made at different times. Thus, once the reliability of a
given stock is established, the accuracy of the results with it may be
regarded as fixed.
For the purpose in hand the whole series is of course unnecessary.
It is well, however, to prepare two extra solutions, one on either side of
the one to which the unknown solution is to be compared. This permits
of a check on the accuracy of the standard, whose color should be in-
termediate between the colors of the other two. It also allows a more
accurate and rapid adjustment of the reaction of the unknown, the color
of which may be made roughly to match that of one of the solutions
above or below the one finally sought and then carefully brought to the
ultimately desired point. If, on the other hand, the end point is slightly
overreached in the process it may be detected more easily and the magni-
tude of the error approximately judged by comparison with the third
solution.
In this laboratory comparisons are made in test tubes 7 X # inches
placed in a comparator similar to that described by Dernby and Avery'.
The following procedure is recommended for the preparation of neu-
tral ammonium citrate solutions. When carefully carried out it yields
solutions having densities of 1.09 in which the ratio of ammonia to an-
hydrous citric acid is 1 to 3.794 + 0.015.
Neutral ammonium citrate solution—¥or every liter of solution required dissolve
172.00 grams of anhydrous or 188.13 grams of crystallized citric acid in approximately
700 ce. of water; nearly neutralize with commercial ammonium hydroxide; cool; measure
the volume of the solution or make it up to a convenient volume, taking care to keep
the density above 1.09; make exactly neutral, testing as follows: With a pipet transfer
5 ce. of the citrate solution to a 7 X 7 inch test tube and dilute to 20 cc. with distilled
water. Add from a dropping bottle 5 drops of a 0.02% solution of phenol red (pre-
pared by diluting a 0.4% stock solution containing 0.1 gram of the dye ground
in an agate mortar with 5.7 cc. of 0.05N sodium hydroxide and made up to 25 cc.).
From a buret run in standard ammonia solution until the color approximates that of
an equal volume of a neutral standard phosphate solution (prepared by mixing 50 cc.
M/5 dihydrogen potassium sulfate and 29.63 cc. M/5 sodium hydroxide and making
up to 200 cc.) contained in a similar test tube and with the same concentration of
1J. Exp. Med., 1918, 28: 348.
1921] HASKINS: PHOSPHORIC ACID IN PRECIPITATED PHOSPHATES 97
indicator. Complete the process by carefully adding the standard ammonia solution
in small amounts and comparing the colors in the colorimeter. From the amount of
ammonia solution required to produce in the sample a color which exactly matches
that of the standard, calculate the amount required to neutralize the rest of the solu-
tion.
Add this calculated amount of ammonia to the original solution and check its reaction
against that of the neutral standard, using the technique described above. If the colors
match, dilute the solution to 1 liter for every 172.00 grams of anhydrous citric acid
used.
Finally check the composition of the solution by determining the ratio of ammonia
_ to citric acid by the method of Patten and Marti' and its density by means of a hydro-
meter.
RECOMMENDATIONS.
It is recommended—
(1) That a neutral solution of ammonium citrate be considered as one
in which the ratio of ammonia to anhydrous citric acid is 1 to 3.794 and
which shall contain 45.33 grams of ammonia and 172.00 grams of an-
hydrous citric acid per liter at 20° C.
(2) That the method described on page 98, be made the official method
for the preparation of neutral ammonium citrate.
H. P. Nelligan (American Glue Company, Boston, Mass.) presented
a paper on ‘‘Limitations of the Present Official Methods of Analysis for
Insoluble Phosphoric Acid in Dicalcium Phosphate’’. Considerable
discussion followed the reading of this paper with the result that it was
re-referred to Committee A and H. D. Haskins invited to sit with the
committee when it met. Committee A, however, failed to report upon
the matter.
REPORT ON AVAILABLE PHOSPHORIC ACID IN
PRECIPITATED PHOSPHATES.
By H. D. Haskins (Agricultural Experiment Station, Amherst, Mass.),
Associate Referee.
At the request of R. N. Brackett, General Referee on Fertilizers, the
writer consented to act in the capacity of Associate Referee on Available
Phosphoric Acid in Precipitated Phosphates. The studies which have
been made on this subject during the year have been carried on in the
laboratories of the Massachusetts Agricultural Experiment Station and
no attempt has been made to secure results from other experiment sta-
tions or fertilizer control chemists for the reason that very little precip-
itated phosphate seems to be distributed to the farmer when unmixed
1 J. Ind. Eng. Chem., 1913, 5: 567.
98 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
with other materials except in the Connecticut River tobacco districts
and among the citrus fruit growers of Florida and possibly some other
Southern States. Your associate referee did not feel justified in asking
for the cooperation of chemists who were already overworked with other
problems and who would have only a passing interest in this particular
subject. Some data, however, have been secured from H. P. Nelligan,
a representative of the American Glue Company, which will form a part
of this report. It may be of interest to add that the Belgian and German
chemists use what is known as the Petermann method, employing 1 gram
of the precipitated phosphate with 100 cc. of alkaline citrate of ammonia.
Italian and French chemists also have special methods for testing pre-
cipitated phosphate. The Italian method employs 100 cc. of neutral
citrate of ammonia with a 3-gram charge, while the French method
calls for 40 ce. of a slightly alkaline solution of citrate of ammonia with
a 4-gram charge. The material which has served for the studies which
make up this report was supplied by the American Glue Company of
Boston and represented their ordinary run of precipitated phosphate.
It tested 39.22 per cent of total phosphoric acid (average of seven deter-
minations).
SCOPE OF THE EXPERIMENT.
The experiment was planned to show: (1) A comparison of results
obtained by the use of a 1- and 2-gram charge with a manipulation as
outlined in the official methods for the determination of soluble and in-
soluble phosphoric acid in fertilizers!; (2) a comparison of results obtained
by the use of 100 cc., 150 ec. and 200 cc. of neutral citrate of ammonia
on a 2-gram charge; (3) the effect of two successive treatments, each
employing 100 cc. of neutral! citrate of ammonia, on a 2-gram charge
of the precipitated phosphate (the properly washed residue obtained
after treating 2 grams of the phosphate was introduced into an Erlen-
meyer flask together with the filter paper and the whole treated with
a second application of 100 cc. of neutral citrate of ammonia); (4) a
study of the behavior of the phosphate when mixed with other crude
stock materials, as in the manufacture of a complete fertilizer (a 4-8-4
mixture was made up by the use of nitrate of soda, dried blood, sulfate
of potash and magnesia, precipitated bone, and peat filler; results were
obtained by treating a 1- and 2-gram charge with neutral citrate of am-
monia according to the association methods); (5) an experiment was
run to note the effect of maintaining a constant temperature at 65° C.
of the neutral citrate solution while filtering and washing after the treat-
ment of 2 grams of the phosphate with 100 cc. of neutral citrate of am-
monia. It was thought that perhaps the high insoluble phosphoric acid
tests that were obtained when 2 grams of the phosphate were treated
with 100 ce. of neutral citrate of ammonia solution were due to a partial
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 4-5.
1921 HAS
99
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100 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
precipitation of the dicalcic phosphate from the highly saturated solution
of neutral citrate of ammonia during the filtration process.
Results have been obtained on these studies by two analysts, Walker
and Clarke. The tabulated results are given in Table 1.
Nore 1.—In the 4-8-4 fertilizer mixture where the precipitated phosphate was used
as the only source of phosphoric acid, when employing 100 cc. of neutral citrate of
ammonia, a 2-gram charge gave citrate-insoluble phosphoric acid, 0.08 per cent, and
a 1-gram charge gave 0.10 per cent.
Nore 2.—In the filtration of all of the citrate solutions double filters were used;
quality C.S. & S. No. 597, 11 cm. Gentle suction was employed with a platinum cone.
Norte 3.—The material showed the presence of 40.62 per cent of calcium oxide and
7.24 per cent of water.
The following determinations were made by the official method!,
using Whatman paper No. 2, gentle suction with a platinum cone.
TABLE 2.
Results obtained in the determination of citrate-insoluble phosphoric acid.
(Analyst, H. P. Nelligan.)
“PHOSPHORIC ACID.
SAMPLE
2-gram charge | 1-gram charge
per cent per cent
A 4.31 2.10
B 5.02 2.80
Cc 3.40 1.90
D 4.10 2.03
E 3.80 1.90
F 3.04 1.20
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 4.
1921] HASKINS: PHOSPHORIC ACID IN PRECIPITATED PHOSPHATES 101
DISCUSSION OF RESULTS.
The results obtained by both analysts at the Massachusetts Agri-
cultural Experiment Station show a considerably higher availability
of the phosphoric acid with a 1-gram charge than when 2 grams are
used, as called for in the official methods. The same is true on the work
of the analyst from the American Glue Company when working on six
different samples of precipitated phosphate. All of these results bear out
the observations of the writer on earlier studies of this class of materials.
_ The additional results obtained by Walker in the use of 150 and 200 ce.
of citrate of ammonia with a 2-gram charge of phosphate also show an
increasing amount of available phosphoric acid, the use of 200 cc. of
neutral citrate of ammonia with a 2-gram charge of phosphate giving
about the same availability as 100 cc. when using a 1-gram charge. The
results obtained by Clarke, using a 2-gram charge with two successive
treatments of 100 cc. each of neutral citrate of ammonia, show 100 per
cent availability of the phosphoric acid. The results obtained by Walker
on the 4-8-4 fertilizer mixture which contained all of its phosphoric acid
in the form of precipitated phosphate would indicate that when this
product was used as a source of phosphoric acid in the average mixed
fertilizer its availability by the official method would be very high
(over 99 per cent).
The experiment which was run to study the effect of maintaining a
constant temperature of 65° C. of the citrate solution during filtration
resulted in having but little effect on the availability of the phosphoric
acid in the product. The results at hand would, therefore, indicate that
the low availability of the phosphoric acid in precipitated phosphate
when run by the official method, using a 2-gram charge with 100 cc. of
neutral citrate of ammonia, was due to a saturated citrate solution,
resulting from the large amount of dicalcic phosphate present.
With regard to the availability of the phosphoric acid in precipitated
phosphate as measured by vegetation tests, it may be said that a 2-
year test on the phosphate fields at the Massachusetts Agricultural
Experiment Station with corn and grass and clover shows a satisfactory
crop, as may be seen from the following results:
-
102 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No 7
TABLE 3.
Results of a 2-year test on phosphate fields.
1919 CROP CORN
YIELD PER ACRE 1920 GRASS AND
PHOSPHATE CLOVER
PER ACRE
GRAIN STOVER
bushels pounds pounds
Plot 1 | No phosphoric acid............ 83.0 4840 6902
Plot: 2: | Tennessee:rock:..< cc oe ooceiene 58.1 4560 6632
Plot. 3: | Acid'phosphaté. =. 2.253. 2..... 51.8 6160 8122
Plot 4 | Florida soft rock.............. 55.0 4680 7868
lotion |sBasic-slag net eeeeeia aoe 72.9 8280 7738
Plotm6)||stesmed bones) ae oo eee 78.8 3840 8594
Plot 7 | No phosphoric acid............ 55.5 3640 7896
Plot 8 | Precipitated bone*............. 78.9 7440 8208
Plot 90 | WR webone ee eee ae. re 77.4 8520 7438
Plot 10 | Tennessee rock... ...0.......0. 64.8 7120 8136
Plot i (Steamedsbone oe aa. eee oe inlet 6920 8452
Blotet2| Acid phosphave sec nose sse ieee 72.4 5960 7836
Plot 13 | No phosphoric acid............ 54.0 3480 6382
* Previous to 1919 this plot had received dissolved bone black as phosphoric acid source.
It may be added that in general farm practice among the tobacco
growers of the Connecticut Valley the precipitated phosphate has for
years received the preference, even with an advance in price, over acid
phosphate.
RECOMMENDATION.
Your associate referee is convinced that the present official method
for the determination of available phosphoric acid does not give full
justice to this class of materials, and he would therefore recommend
that the determination of insoluble phosphoric acid in precipitated
phosphate be carried out according to the present official method for the
determination of insoluble phosphoric acid in fertilizerst with the ex-
ception that a l-gram charge be employed and that a quality of filter
paper corresponding to C. 8S. & S. No. 597 be used, together with a per-
forated platinum cone and gentle suction, in the filtration of the citrate
solution after treatment.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 4.
1921) CLARK-KEELER: DETERMINATION OF PHOSPHORIC ACID 103
A MODIFIED METHOD FOR THE DETERMINATION OF
PHOSPHORIC ACID.
By A. W. Crark and R. F. KEeter (Agricultural Experiment Station,
Geneva, N. Y.).
During the past four years considerable work has been done in the
writers’ laboratory on a gravimetric method for the determination of
_ phosphoric acid, based on the weight of the ammonium phosphomolyb-
date precipitate. While it is not claimed that there is any new principle
involved, the main differences between the method employed by the
writers and the usual procedure are: the precipitation at room tempera-
ture; drying the precipitate for 2 hours at 120° C.; and the factor for
phosphoric acid.
The investigation of the first two years was of a preliminary nature.
A slightly different factor was used from that finally adopted and dry-
ing of the precipitate was effected at a temperature of 110° C., main-
tained for a period of 1 hour. Some 2500 analyses were made and
compared with the official magnesium gravimetric method, from which
a factor was derived.
Upon drying the yellow precipitate for 2 hours at 120° C., the factor
variation was greatly reduced and gave better agreement between dupli-
cate determinations. The factor was found to vary slightly from the one
previously used. The method employed is as follows:
Dissolye 2 grams of the sample in 30 cc. of concentrated nitric acid and 10 ce. of
hydrochloric acid. Boil until solution is complete, cool, dilute to a volume of 200 cc.,
mix and pour through a dry filter. Neutralize a portion equivalent to 0.25 gram with
ammonium hydroxide and acidify with nitric acid. Add 50 cc. of 20% ammonium
nitrate solution; and then sufficient ammonium molybdate solution to completely
precipitate the phosphorus (35 cc. added for samples containing between 6 and 12
per cent of total phosphoric acid). Do not heat the solution but allow it to stand over-
night at room temperature. Filter on a weighed porcelain Gooch crucible of 25 ce.
capacity dried at 120°C. Wash eight times with 2% nitric acid, filling the crucible
about half full each time. Wash twice with cold distilled water, dry for 2 hours at 120°C.,
and weigh.
Determinations in duplicate by one of the writers, using the official
method, and single determinations by the other, using the above method,
were made upon 95 samples.
59 samples, or 62.1 per cent, showed a difference of 0.10 per cent or less.
27 samples, or 28.4 per cent, showed a difference between 0.10 and 0.20 per cent.
9 samples, or 9.5 per cent, showed a difference of 0.20 per cent or more.
No samples showed a difference of 0.31 per cent or more.
The factor used for converting the weight of the ammonium phos-
phomolybdate to phosphoric acid is 0.03723.
104 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
For the determination of insoluble phosphoric acid, an aliquot of 50
cc., corresponding to 0.50 gram, is recommended. In this case 25 ce.
of a 40 per cent solution of ammonium nitrate are added after neutraliz-
ing with ammonium hydroxide and acidifying with nitric acid.
REPORT ON NITROGEN.
By I. K. Poetrs (Bureau of Chemistry, Washington, D. C.), Associate
Referee on Nitrogen in Fertilizers.
It was recommended in 1919! that a study of the du Pont nitrometer
be made in order to determine its practicability for the estimation of
nitric and nitrous nitrogen. An attempt was made to secure collaborators
to carry out this study, but the war prevented securing the desired
number. A number of those who signified their willingness to do this
work failed to report their results. The few reports received are not
presented since they are insufficient to be convincing.
The writer had analyses made, among other samples, of a check sample
of potassium nitrate of the E. I. du Pont de Nemours & Company, dupli-
cates of which were used to check up the various nitrometers in use at
the du Pont Laboratories. The weights of nitrous oxide found on four
estimations on a l-gram sample were 0.29667 gram; 0.29710 gram;
0.29732 gram; 0.29732 gram. The average of the four samples was
0.29710 gram of nitric oxide gas which, calculated to potassium nitrate,
is 100.07 per cent of that taken.
Beckett? has investigated the du Pont nitrometer as applied to the
analysis of explosives. He concludes that there is an appreciable quan-
tity of nitrogen and nitrous oxide gas left in the sulfuric acid residue
after the estimation of nitrogen in du Pont’s high nitrogen gun cotton,
gun cotton, highly soluble nitrocellulose, blasting soluble nitrocellulose
and sodium nitrate.
In conclusion, Beckett states that the nitrometric estimation of nitro-
gen in nitrocellulose is invariably too low. He has found that the time
which is allowed to elapse between the introduction of the nitrocellulose
and sulfuric acid into the nitrometer and the shaking has a great in-
fluence on the results, in the case of nitrocellulose. This effect is less in
the case of inorganic compounds. The truest results are obtained by
using 15 cc. of 92.5 to 94 per cent sulfuric acid and by allowing 15 minutes
to elapse between the introduction of the nitrocellulose and acid into
the nitrometer and shaking. In this case he states that the error is
approximately 0.7 per cent.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 365.
2 J. Chem. Soc., 1920, 117: 220.
1921] PHELPS: REPORT ON NITROGEN 105
RECOMMENDATIONS.
Since the du Pont nitrometer can be used only in the analysis of in-
organic nitrates and mixed acids and then only by approximating the
true results through the approximate elimination of the errors in the
method by standardization with a pure nitrate, and since a better method
for fertilizer control appears available, it is reeommended—
(1) That the study of the du Pont nitrometer be abandoned.
(2) That the referee for 1921 be directed to study the Devarda alloy
method! as applied to the determination of nitric and nitrous acids in
fertilizers.
TABLE 1.
Analysis of check sample of potassium nitrate from E. I. du Pont de Nemours ¢ Company.
(Analyst, L. J. Jenkins.)
NITROGEN FOUND EQUIVALENT AMMONIA EQUIVALENT POTASSIUM NITRATE
per cent per cent per cent
13.85 16.84 99.93
13.87 16.86 100.07
13.88 16.88 100.14
13.88 16.88 100.14
TABLE 2.
Sample of potassium nitrate recrystallized in the Bureau of Chemistry.
NITROGEN FOUND EQUIVALENT AMMONIA EQUIVALENT POTASSIUM NITRATE
per cent per cent per cent
13.81 16.79 99.64
13.86 16.85 100.00
BORIC ACID FOR NEUTRALIZING AMMONIA IN
NITROGEN DETERMINATIONS?
By H. D. Spears (Agricultural Experiment Station, Lexington, Ky.).
Scales and Harrison*® give results that suggest that boric acid for
neutralizing the ammonia in nitrogen determinations‘ would be desir-
able for feeding stuffs analysis. The method according to Scales and
Harrison has the following advantages:
1 Chem. Zig., 1892, 16: 1952; J. Ind. Eng. Chem., 1919, 11: 306; 1920, 12: 352.
2 Presented by I. K. Phel
Ips.
8 J. Ind. Eng. Chem., 1920, 12: 350.
*Z. angew. Chem., 1913, 26: 231.
106 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
1.—It does away with the occasional errors that arise from slight mistakes in
measuring the sulfuric acid into the receiving flask.
2.—As the boric acid solution need be measured only approximately, much time
can be saved, and an unskilled helper can measure it into the receiving flasks.
3.—By proper adjustment of the strength of the standard acid and the weights
of the samples taken the percentage of nitrogen can be read directly from the buret.
4.—It is necessary to prepare accurately only one standard solution, ¢. e., the sulfuric
acid for titrating.
Ninety-five mg. of nitrogen as ammonia can be recovered in the distillate when
50 ce. of 4% boric acid is used.
Bromophenol blue is a better indicator than those used by the other investigators.
In laboratories where it is necessary to run a great number of nitrogen
determinations, the above-mentioned advantages are highly desirable,
though Item No. 3 is not peculiar to the boric acid method.
In order to have a fair comparison of the two methods, sixty labora-
tory samples of feeding stuffs, taken in the order in which they were
received, were run by both methods, a modified Kjeldahl method using
sulfuric acid as the neutralizing agent (the regular laboratory method),
and the boric acid modification of the Kjeldahl method.
LABORATORY METHOD.
Digest 0.7005 gram of the ground sample, 10 grams of powdered sodium sulfate, 1 cc. of
saturated copper sulfate solution and 30 cc. of concentrated sulfuric acid for 3 hours.
Cool, dilute, add about 90 cc. of amixture of saturated caustic soda and potassium sulfide
(40 grams of potassium sulfide per liter) and then a small amount of 20-mesh zinc, and
distil into sulfuric acid. Titrate the excess sulfuric acid with 0.1N sodium hydroxide,
using 4 drops of a 1 per cent solution of alizarin as the indicator. Measure the sulfuric
acid with an automatic pipet. A blank is run, using all reagents. It is not necessary
to know the normality of the sulfuric acid used. The difference between the cc. reading
of the blank and the determination gives the amount of 0.1N sodium hydroxide equiva-
lent to the nitrogen. Instead of using a 0.1N sodium hydroxide solution, a solution,
1 ce. of which is equivalent to 1 mg. of nitrogen, may be used, and the weight of the
sample taken may be 1 gram instead of 0.7005 gram so that the per cent of nitrogen
can be read directly from the buret.
BORIC ACID MODIFICATION.
Conduct the digestion as above, receive the distillate in 50 cc. of a 4 per cent solution
of boric acid. Titrate as suggested by Scales and Harrison (artificial light) and use
6 drops of a 0.04 solution of bromophenol blue as the indicator. A blank, using all
reagents, is run and subtracted from the determination. Tenth-normal sulfuric acid
was used to titrate the distillate.
1921] SPEARS:
TABLE 1.
Nitrogen in feeding stuffs.
BORIC ACID IN NITROGEN DETERMINATIONS 107
* See Table 2.
DESCRIPTION OF SAMPLE
Hog feed
Mixed wheat feed
Hog feed
Shipstuff
Mixed wheat feed
Wheat middlings
Barley mixed feed
Dry mash
Wheat shorts
Wheat middlings
Wheat mixed feed
Cracked corn
Dairy feed
Mixed middlings
Cottonseed meal
Cottonseed meal
Cottonseed meal
Mixed feed
Mixed feed
Horse feed
Ground oats
Hog ration
Dairy feed
Dairy feed
Dairy feed*
Cracked corn*
Velvet bean feed*
Horse feed*
Dairy feed*
Winter wheat middlings*
Mixed feed
Horse and mule feed
Mixed feed
Mill feed
Mixed feed
Sewage sludge
Horse and mule feed
Hog and dairy feed
Hen feed
Horse and mule feed
Mixed feed
Alfalfa and cow feed
Mixed feed
Hog feed
White hominy feed
Horse and mule feed
Alfalfa and molasses
Cottonseed meal
Cottonseed feed
Horse and mule feed
Wheat bran
Horse and mule feed
Dairy feed
Horse feed
Hen feed
Little chick feed
Dairy feed
Digester tankage
Pig meal
Hog feed
IAS CLR Clpareits votre eaetsis osha sores
BORIC ACID
NEUTRALIZING
AGENT
per cent
2.95
2.80
3.37
2.66
2.67
2.59
2.32
2.59
3.03
2.63
2.85
1.43
2.53
2.57
6.40
6.67
6.33
2.54
2.62
1.68
2.00
2.79
2.71
2.38
SOR Selec GRRE eS ao rs J aR at Fy a
NH OHOOR UE UNO OROMbHDURDHUwWHOw
NSSAADA AW SSTORHAGOHBATNORDS
SULFURIC ACID
NEUTRALIZING
AGENT
per cent
2.92
2.78
3.40
2.68
2.68
2.56
2.36
2.60
3.00
2.64
2.88
1.48
NN NOCWN HE RWEN EWAN EEE NEN EEN NNN
NN NHOOR NH UMNO OUNORDOURHUWHNORWRE
DSNUSSSENRASSRTZRRESSESR BOSSES
108 ASSOCIATION OFQOFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Bromocresol purple, an indicator giving two very decided colors—
purple to yellow—from alkalinity to acidity—was also tried in the same -
manner as bromophenol blue with the following good results:
TABLE 2.
Nitrogen in feeding stuffs, bromocresol purple as an indicator.
BORIC ACID FIXING
DESCRIPTION OF SAMPLE
AGENT
per cent
Dairy feed 3.86
Cracked corn 1.46
Velvet bean feed 2.84
Horse feed 1.75
Dairy feed 3.36
Winter wheat middlings 2.32
From the figures in the tables it is seen that the methods are quite
comparable. The writer is of the opinion that there is not much choice
between the two methods. It is true that errors might occur in measur-
ing the sulfuric acid used as the neutralizing agent, but titrating with
artificial light, although a satisfactory end point is obtained, is hardly
as desirable. In one case, an accurately standardized acid is used, and
in the other, an accurately standardized alkali.
THE KJELDAHL NITROGEN METHOD AND ITS
MODIFICATIONS.
By A. E. Paut?and E. H. Berry (U.S. Food and Drug Inspection Station,
Transportation Building, Chicago, IIl.).
Because of the importance of nitrogen in all matters pertaining to
nutrition, the determination of this element is one of the most important
if not the most important, to every food analyst. In the case of feeding
stuffs particularly, the percentage of nitrogen frequently forms the
basis for the evaluation of the material. Unfortunately, the methods
in use at the present time are not entirely satisfactory and considerable
difficulty has been experienced by many analysts in securing concord-
ant and entirely satisfactory results. Three different types of methods
have been used in the past: (1) The absolute method of Dumas, which
involves dry combustion and reduction of the gaseous products by a
copper foil and measurement of the nitrogen formed; (2) the method
of Will and Warrentrapp, in which the material is heated with soda lime
1 Presented by I. K. Phelps. Cae ren p ;
2 Present address, U. S. Food and Drug Inspection Station, Government Building, Cincinnati, Ohio.
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 109
and the ammonia formed either titrated or weighed as ammonium platinic
chloride; (3) the Kjeldahl method of converting the nitrogen present
into ammonium sulfate by heating with strong sulfuric acid, then libera-
ting the ammonia by means of strong soda solution, distilling and titra-
ting.
The first two methods mentioned are the oldest. They are highly
accurate, but very time-consuming and laborious. The Kjeldahl method
is the one which is at present almost universally employed by food
control officials and commercial chemists. This method, while simple
in principle, requires considerable skill and close attention to minute
details. The method itself was first described by Kjeldahl in 18831.
It seems that wet combustions, involving the use of alkali and potas-
sium permanganate, were known prior to Kjeldahl’s original article
and it was by way of modification of the wet combustion process that
Kjeldahl undertook the decomposition with permanganate under acid
conditions. It should be emphasized that the use of an oxidizing agent
was considered by Kjeldahl a vital step in the process and he attempted
the use of phosphorus pentoxide and potassium dichromate, but con-
sidered permanganate preferable. The use of mercury or mercuric oxide
was not mentioned by Kjeldahl in his original work.
It is extremely interesting to note that while potassium permanga-
nate is a reagent upon which, to a large extent, the Kjeldahl method was
originally based, the process has in the course of time been so modified
that the desirability of its use is extremely doubtful.
Since Kjeldahl’s article first appeared a number of investigations
have been made by various chemists and an endless number of articles
written on the subject. A great deal of good work has been done, al-
though the results reported in some instances would indicate that the
experimental work was not of an entirely satisfactory character. In
these articles many modifications are suggested and the use of a large
number of chemicals was investigated. However, only one or two investi-
gators have introduced features which are of importance to the Kjeldahl
method. Of these, an article written by J. W. Gunning in 1889? deserves
first mention. Gunning found by the use of potassium sulfate that the
time required for digestions may be very materially shortened.
The work of Wilfarth? should also receive recognition, since he first
advocated the use of mercury.
There do not seem to have been published results of any investiga-
tion which take into consideration all the details of the method with the
view to determining the causes for discrepancies in results, or the extent
to which results may be affected by details in manipulation. It seemed
1 Compl. rend. trav. lab. Carlsberg, 1883, 2. 1: Z. anal. Chem., 1883, 22: 366.
2 Z. anal. Chem., 1889, 28: 188.
2 Chem. Zentr., 1885, 56: 17, 113.
110 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
desirable that such an investigation be undertaken in order that an
analyst might understand fully where danger of inaccuracies lies and
that he be advised as to the best means of avoiding these discrepancies.
It also seemed desirable, in order that concordant and _ satisfactory
results might be obtained, that minute details for carrying out the
various steps in the Kjeldahl method be described.
The analyst who has had considerable experience with the Kjeldahl
method is aware of the fact that more difficulty is experienced with some
kinds of products than with others, and it seems that particular difficulty
has been experienced with cottonseed meal. Cottonseed meal is an
article which, at the present time, is of utmost importance and it is par-
ticularly desirable that the details of the method be so worked out as to
yield accurate results on this commodity. It was with this material that
the greater part of the work here recorded was done.
In conducting this investigation, the plan was to study first the in-
fluence of the various parts of the necessary apparatus. This work was
carried out by the use of pure salts of ammonia. Subsequently, the details
of the digestion were given careful consideration. This was accomplished
in part on pure ammonium salts, and in part on samples of cottonseed
meal, A and B. Thereafter, the method was studied with the samples
indicated and the most desirable details decided upon and finally applied
to products other than cottonseed meal.
The ammonium salts used as standards were C. P. products of Baker
and Adamson. Careful examination in this laboratory showed them to
be of a high degree of purity, fully within our requirements.
It will be noted that the greater part of the work was done upon the
two samples, A and B, which were unknowns, so far as actual percentage
of nitrogen was concerned. However, the number of determinations
made was so great that there can be no doubt as to the actual nitrogen
content: Sample A, 46.2 per cent; Sample B, 30.5 per cent.
The experimental work which was accomplished is described essentially
in the tables. In order that they may be followed more readily, it seems
desirable to explain them in a general manner at this time, and to tab-
ulate and classify the headings.
The work is divided primarily into three parts. The first part includes
Tables 1 to 10, and is a study of the effect of the use of various types of
apparatus, and the various reagents which required attention. In this
work only chemicals known to be pure were studied. Tables 1 to 5 are
devoted to the operation of distillation. It may seem rather inconsistent
to have commenced at the last of the operations involved in the deter-
mination of nitrogen by the Kjeldahl method, but it will be seen readily
that by fixing the necessary details, step by step in the reverse order, the
entire process may be worked out, while in starting with the first step
there would always be an uncertainty as to whether observed difficul-
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 111
ties are caused at the point under consideration or at some later point.
In the work recorded in Tables 6 to 10, the proper method of applying
heat during the digestion with sulfuric acid is studied. The question of
the use of an asbestos guard to confine the flame to that portion of the
flask which contains the acid, is also taken up, also the necessity for the
use of potassium sulfide.
In the second group of tables, which includes Tables 11 to 17, there
are recorded the results obtained by the use of two samples of cotton-
seed meal. The purpose was to study the details for the successful de-
-composition of this substance.
Table 18 is a compilation of results obtained by the use of the details
of the method which have been found to be most desirable.
Tables 19 to 23 give the results obtained on other common nitrogenous
substances by this method.
The third group of tables, 24, 25, 26, represents an incidental study of
the effect of nitrous fumes in the atmosphere surrounding the digestion,
and of nitrates in the substance. This part of the work proved of un-
expected interest.
To summarize, the subject matter may be arranged as follows:
APPARATUS AND REAGENTS.
DISTILLATION.
Table 1.—Efficiency of connecting bulbs.
Table 2.—Efficiency of distillation apparatus used throughout experiments.
Table 3.—Effect of varying quantities of standard acid and water in the receiving
flasks.
Tables 4, 5.—Effect of quantity of distillate.
DIGESTION.
Table 6.—Effect of loss of sulfuric acid.
Table 7.—Effect of the use of a short-necked flask.
Table 8.—Effect of overheating.
Table 9.—Effect of use of asbestos guard.
Table 10.—Influence of the use of potassium sulfide.
DIGESTION OF COTTONSEED MEAL.
Table 11.—Effect of potassium permanganate.
Table 12.—Results of use of sulfuric acid alone.
Tables 13 and 14.—Influence of time on digestion. :
Table 15.—Quantity of mercuric oxide.
Table 16.—Quantity of copper sulfate.
Table 17.—Quantity of sample used.
Table 18.—Series of results by use of proposed details.
RESULTS ON OTHER COMMON COMMODITIES.
Tables 19-23.
EFFECT OF NITRATES OR NITROUS FUMES.
Tables 24-26.
112 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
TABLE 1.
Efficiency of connecting bulbs*.
0.1 N AcID EQUIVALENT PROTEIN
TYPE OF BULB NEUTRALIZED CALCULATED ON 2-
GRAM CHARGE
cc. per cent
Plain bent tube, internal diameter ? inch. 2.2 0.96
1.7 0.74
1.9 0.83
1.4 0.61
Bent tube with plain bulb, diameter about 13 1.0 0.44
inches. 0.6 0.26
1.7 0.74
0.6 0.26
Kjeldahl connecting bulb, with internal inlet and 0.2 0.09
outlet tubes bent in opposite directions. 0.3 oF
0.1 0.04
* Saturated sodium hydroxide, 100 cc., was diluted to 300 cc. and distilled into 0.1N acid.
TABLE 2.
Efficiency of distillation apparatus used throughout experiments.
0.1 N ACID REQUIRED | EQUIVALENT PROTEIN
IN DISTILLATION FLASK TO TITRATE ABOUT CALCULATED ON
200 cc. of DISTILLATE 2-GRAM CHARGE
ce. per cent
300 cc. of distilled water. None None
300 ce. of distilled water and 1 cc. of saturated
sodium hydroxide. None None
250 ce. of distilled water and 50 cc. of saturated
sodium hydroxide. None None
200 cc. of distilled water and 100 cc. of saturated
sodium hydroxide. 0.1 0.04
The figures in Table 1 show that the Kjeldahl connecting bulb, as
described, is much more efficient than other forms. Table 2 confirms this
statement. This apparatus was used throughout this investigation.
1921;
PAUL-BERRY: KJELDAHL NITROGEN METHOD 113
TABLE 3.
Effect of varying quantities of standard acid and water in the receiving flasks.
5 ce.
5 ce.
8 cc.
10 ce.
15 ce.
~ 25 CC.
50 ce.
5 cc.
8 ce.
10 ce.
15 ce.
25 cc.
IN RECEIVING FLASK
of water only
of N hydrochloric acid
of N hydrochloric acid
of N hydrochloric acid
of N hydrochloric acid
of N hydrochloric acid
of water only
AMMONTA FOUND
AMMONIA RECOVERED*
of N hydrochloric acid + 45 cc. of water
of N hydrochloric acid + 42 cc. of water
of N hydrochloric acid + 40 cc. of water
of N hydrochloric acid + 35 ce. of water
of N hydrochloric acid + 25 cc. of water
gram
0.1498
0.1549
0.1588
0.1591
0.1591
0.1593
0.1540
0.1578
0.1585
0.1590
0.1590
0.1593
per cent
94.21
97.42
99.87
100.06
100.06
100.19
96.85
99.24
99.68
100.00
100.00
100.19
* Ammonium chloride (0.1590 gram of ammonia) was dissolved in 250 ce. of water, 50 cc. of saturated
sodium
hydroxide added and distilled.
From Table 3 it will be seen that when enough acid is used in the
receiving flask to neutralize 85.5 per cent of the ammonia distilled
over, the amount retained was 99.87 and 99.68 per cent. Therefore, while
it is advisable to use sufficient acid to neutralize all the ammonia to be
distilled over, it is not absolutely necessary.
TABLe 4.
Effect of quantity of distillate.
DISTILLATE
AMMONIA FOUND
gram
0.1377
0.1563
0.1583
0.1588
0.1591
0.1590
0.1588
0.1590
0.1590
0.1590
0.1590
0.1590
| AMMONIA RECOVERED*
per cent
86.60
98.30
99.56
99.87
100.06
100.00
99.87
100.00
100.00
100.00
100.00
100.00
* Ammonium chloride (0.1590 gram of ammonia), 250 ec. of water and 50 cc. of saturated sodium hydrox-
ide.
114 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TABLE 5.
Cuantity of distillate necessary when very large amounts of nilrogen are present.
DISTILLATE AMMONIA FOUND AMMONIA RECOVERED*
cc. ‘ gram per cent
50 0.3176 99.87
0.3165 99.53
75 0.3169 99.65
0.3181 100.03
100 0.3176 99.87
0.3176 | 99.87
150 | 0.3177 | 99.90
0.3182 100.06
200 0.3177 99.90
* Ammonium chloride (0.3180 gram of ammonia), 250 cc. of water and 50 cc. of saturated sodium hydrox-
ide.
The results in Tables 4 and 5 show that practically all of the ammonia
is distilled over with the first 75 cc. of distillate and all of it with 100 cc.
TABLE 6.
Effect of the loss of sulfuric acid.
NO POTASSIUM SULFATE USED 10 GRAMS OF POTASSIUM SULFATE
USED
VOLUME IN DIGESTION
FLASK ABOUT
AMMONIA AMMONTA AMMONIA AMMONIA
FOUND RECOVERED* FOUND RECOVERED*
ce. gram per cent gram per cent
5 0.1580 99.37 0.1573 98.92
0.1581 99.43 0.1583 99.56
10 0.1590 100.00 0.1590 100.00
0.1513 95.16 0.1591 100.06
20 0.1590 100.00 0.1590 100.00
0.1587 99.82 0.1587 99.82
* Ammonium chloride (0.1590 gram of ammonia) and 25 ce. of sulfuric acid.
1921) PAUL-BERRY: KJELDAHL NITROGEN METHOD 115
TABLE 7.
Effect of the use of a short-necked flask (8 inches over all).
ASBESTOS GUARD NOT USED ASBESTOS GUARD USED
CONTENTS| POTASSIUM SULFATE 10 GRAMS OF POTAS- POTASSIUM SULFATE 10 GRAMS OF POTAS-
OF FLASK NOT USED SIUM SULFATE USED NOT USED SIUM SULFATE USED
BOILED TO
ABOUT , |
AMMONTA AMMONIA AMMONIA AMMONIA
AMMONIA | REcoy- | AMMONIA | pecoy- | AMMONIA | pRecoy- | AMMONIA | pecov-
FOUND ERED* FOUND ERED* FOUND ERED* FOUND ERED*
cc. gram per cent gram | _per cent gram per cent gram per cent
5 0.1445 90.88 | 0.0177 11.13 | 0.1585 99.68 | 0.1590 | 100.0
10 0.1367 85.97 | 0.1590 | 100.00 | 0.1590 | 100.00 | 0.1590 | 100.0
CLS SO LOO LOOT ie state sox=sete | toy exehoy=t'caal| be sNckaroyede. || aieuexevavavel||t vsxoseveresema | peevererier
20 0.1564 98.36 | 0.1588 Evil lenn ncuall lamoesoenl Wacrrceu |ocoses
* Ammonium chloride (0.1590 gram of ammonia) and 25 cc. of sulfuric acid.
TABLE 8.
Effect of overheating allowing strong flame to strike flask above acid.
NO POTASSIUM SULFATE USED 10 GRAMS OF POTASSIUM SULFATE USED
CONTENTS OF FLASK TT
BOILED TO ABOUT
AMMONIA AMMONTA AMMONTA AMMONTA
FOUND RECOVERED* FOUND RECOVERED*
ce. gram per cent gram per cent
5 0.1376 86.54 0.1566 98.49
0.1301 81.82 0.1523 95.78
0.1376 86.14 0.1557 97.92
10 0.1522 95.72 0.1552 97.62
0.1500 94.35 0.1535 96.54
Std corn cual Mecodos tosce 0.1569 98.68
* Ammonium chloride (0.1590 gram of ammonia) and 20 ce. of sulfuric acid.
TABLE 9.
Effect of a guard with a long-necked flask*.
10 GRAMS OF POTASSIUM
NO POTASSIUM SULFATE USED
SULFATE USED
CONTENTS OF FLASK
BOILED TO ABOUT 1
AMMONIA AMMONIA AMMONIA AMMONIA
FOUND RECOVEREDt FOUND RECOVEREDTt
ce. gram per cent gram per cent
5 0.1585 99.68 0.1588 99.87
10 0.1590 100.00 0.1590 100.00
* Twelve inches over-all
Ammonium chloride (0. 1590 gram of ammonia) and 25 cc. of sulfuric acid.
116 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
From a study of Tables 6, 7, 8 and 9, the danger from allowing the flame
to play too high upon the flask above the level of the liquid is clearly
brought out. The volume of the liquid should be kept well above 10 cc.
and the flame never allowed to touch the flask above the liquid. These
tables demonstrate most emphatically the danger from this source and
the necessity for some form of safety device. For this purpose, asbestos
guards were used. These consisted of a one-fourth inch sheet of asbestos,
with holes of such size that only that part of the flask which actually
contains the liquid is exposed to the flame.
TABLE 10.
Influence of the use of potassium sulfide.
DIGESTED WITH DISTILLED Spats “=
COVERED*
gram per cent
0.7 gram of mercuric oxide without potassium sulfide 0.1572 98.86
0.7 gram of mercuric oxide without potassium sulfide 0.13899 87.99
0.7 gram of mercuric oxide without potassium sulfide 0.1459 91.76
1 gram of mercuric oxide+1 gram
of copper sulfate without potassium sulfide 0.1445 90.88
1 gram of mercuric oxide-+-1 gram
of copper sulfate without potassium sulfide 0.1459 91.76
1 gram of mercuric oxide +1 gram
of copper sulfate without potassium sulfide 0.1367 85.97
1 gram of mercuric oxide +1 gram
of copper sulfate without potassium sulfide 0.1418 89.18
0.7 gram of mercuric oxide with potassium sulfide 0.1591 | 100.06
0.7 gram of mercuric oxide with potassium sulfide 0.1593 | 100.19
0.7 gram of mercuric oxide with permanganate and potas-
sium sulfide 0.1591 | 100.06
0.7 gram of mercuric oxide with permanganate and potas-
sium sulfide 0.1590 | 100.00
0.7 gram of mercuric oxide with permanganate and potas-
sium sulfide 0.1588 99.87
1 gram of mercuric oxide +1 gram
of copper sulfate with potassium sulfide 0.1590 | 100.00
1 gram of mercuric oxide+1 gram
of copper sulfate with potassium sulfide 0.1586 99.75
1 gram of mercuric oxide +1 gram
of copper sulfate with potassium sulfide 0.1590 | 100.00
1 gram of mercuric oxide +1 gram
of copper sulfate with potassium sulfide 0.1593 | 100.19
0.3 gram of copper sulfate without potassium sulfide 0.1591 | 100.06
0.3 gram of copper sulfate without potassium sulfide 0.1590 | 100.00
0.3 gram of copper sulfate+10
grams of potassium sulfate without potassium sulfide 0.1593 | 100.19
0.3 gram of copper sulfate+-10
grams of potassium sulfate without potassium sulfide 0.1590 | 100.00
0.3 gram of copper sulfate +10
grams of potassium sulfate with potassium sulfide 0.1590 | 100.00
0.3 gram of copper sulfate+10
grams of potassium sulfate with potassium sulfide 0.1586 99.75
* Ammonium chloride (0.1590 gram of ammonia) and 25 cc. of sulfuric acid.
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD isle
From Table i0 it will be seen that there is a loss of from 2 to 15 per
cent of ammonia when mercury is used during digestion, if sulfide is
not employed to precipitate the mercury before distillation. It is claimed
that the property of mercury in holding back part of the ammonia is
due to the formation of mercury-ammonium ccmpounds. These are
broken up by the potassium sulfide. It is also shown by this table that
this property is not shared by copper, and that, therefore, when copper
is used without mercury, the use of sulfide is unnecessary.
In the following experiments, whenever mercury was used in the diges-
tion, potassium sulfide was used in the distillation. When no mercury was
used, the sulfide was in each instance omitted.
DIGESTION OF COTTONSEED MEAL,
It was believed desirable to use in this investigation a high protein
and also a low protein meal and, in order to obtain this, a quantity of
commercial meal was thoroughly air-dried and placed upon a 30-mesh
sieve. The portion which passed through the sieve had the appearance of
a high grade meal and is designated hereafter as Sample A. The portion
which remained upon the sieve was carefully ground and also passed
through the 30-mesh sieve. This portion had a brownish color and ap-
peared to consist largely of hulls. It is designated as Sample B. Both
portions were very thoroughly mixed and were then kept in large, air-
tight, glass-stoppered bottles. Small portions were withdrawn from time
to time for use in the investigation.
These samples contained the following percentages of protein:
Sample A 46.2 per cent;
Sample B 30.5 per cent.
In the following tables all results recorded for these two samples are
in terms of percentage of protein, N X6.25.
118 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TABLE 11.
Effect of potasstum permanganate.
PROTEIN
DIGESTED* POTASSIUM PERMANGA- SUBSEQUENT
NATE ADDED DIGESTION
SAMPLE A SAMPLE B
per cent per cent
Until straw colored excess none 45.04 29.97
Until straw colored excess 2 hours 45.41 29.97
Until straw colored | 0.2 gram ata time} } hour after each
untillgramisadded| addition of po- 44.01 27.96
tassium perman- 43.44 28.53
ganate
Until clear excess 2 hours 45.37 29.66
Until clear excess 4 hours 45.68 30.41
Until clear none none 45.37 30.58
Until clear excess none 45.24 30.06
45.82 30.58
2 hours after clear none none 46.33 30.80
2 hours after clear excess none 45.98 30.76
4 hours after clear none none 46.29 30.71
4 hours after clear excess none 46.37 30.71
6 hours after clear none none 46.16 30.76
6 hours after clear excess none 46.24 30.80
10 hours after clear none none 46.46 30.63
10 hours after clear excess none 46.20 30.67
* Digested 2 grams of sample with 30 cc. of sulfuric acid, 10 grams of potassium sulfate and 0.7 gram of
mercuric oxide.
A study of Table 11 shows that potassium permanganate is of no value.
In fact, the figures would indicate that there is a tendency for loss of
ammonia, and the writers believe its use should be discontinued.
This question has recently been studied by Frear, Thomas and Edmis-
ton', at the Agricultural Experiment Station, State College, Pa., who
found, in working with fertilizers, that a distinct loss of nitrogen results,
especially if the permanganate is added immediately after the flame
under the flask is extinguished. If added later, the loss becomes smaller,
but these authors in no instance record a gain. However, we are advised
by Frear that they, and also D. C. Cochrane, have found indications
of very slightly higher results by the use of this reagent in the examina-
tion of hay and other vegetable materials. However, this work has not
been published, and at all events it would seem from our work that in
general the danger attendant upon the use of potassium permanganate
more than counterbalances the possible advantage which may be gained.
1 J. Assoc. Official Agr. Chemists, 1919, 3: 220.
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 119
TABLE 12.
Digestion with sulfuric acid alone*.
PROTEIN
Sample A Sample B
per cent per cent
45.06 30.19
45.19 30.01
45.15 30.08
* Period of digestion 17 hours with 35 cc. of sulfuric acid on a 2-gram samp e.
From Table 12, in connection with subsequent results, it will be seen
that it apparently is impossible to get maximum results when sulfuric
acid alone is used.
120 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
TaB
Influence of time tn connection with
0.7 Gram OF/9.7 GRAM OF
TIME 5.0 Grams | 10 Grams | 5.0 GRAMS | 10GRAMs | 0.7 GRAM | MERCURIC | MERCUTIC
DIGESTED OF OF OF OF OF OXIDE OXIDE
AFTER CLEAR | POTASSIUM | POTASSIUM SODIUM SODIUM MERCURIC | 5 GRAMS OF |10 GRAMS OF
SULFATET SULFATE SULFATE} SULFATE OXIDE POTASSIUM | POTASSIUM
SULFATE SULFATE
hours per cent per cent per cent per cent per cent per cent per cent
Oa ieeeecrar-rs LEE at eRe eiaeae «lila coer 4555005 | eee 45.37
cept (a lenend ern Le eal teehee 8G fi>:ch0 45 ATS eer 45.82
72 i ARG He si 45256 oi], ake te |||) eee 46.03 46.29 46.29
Nee lle aecoere A SUEZ bail inayS ene JA pester el | Wowieeeers 46.29 46.16
Sonos sll Miecminoe on hepato aor soe ll Gocco. || | caocs 46.29
STAN ceria alls GRIER lh ocwieisoccs alle. seen 45.63 46.24 46.46
pe ome eee tee corde ll Leserom illic oin 45.98 46.38 46.46
a ie cen AGS We seein 46.07 45.89 46.24 46.46
Svan AliGeasreceeers Ws ACh NH | me seeyene 45.85 CLHORL |) Seooc 46.29
Peete ah eeerenks H One ecko en Uns My rics ome Men ILA ots oe 46.42
6 45.72 46.29 45.15 46.20 46°03) ji) ete 46.20
45.76 46.38 45.11 CAO ie re || eS a9 46.16
Bs Fiera sin Paes 45.02 Leena: Beco Be 46.24
See ete seall|t Gece cres 45.11 ao elspa es encore
Siren) Fees Ch a mere le tcemcs 6 | Pe cincio.g || =. 3dc12ic 46.42
TQ. Loe seats AG A Dia | raercto eal | Meee 46.24 | oo... 46.20
Soll Poco sae somber IN coson ll vootos =I moaue If sews e 46.46
Creer ace ol Walasse sis cael lle so crete Pe mosamioue | wolucittal lie -.docx- 46.24
7s i Pee a |i teton lees eilteccom Il pode ' || ws tox 46.37
Stee rk Pua +l pasar a Me| Wes caetem| | stcrase alllioto big J Ge sé. 46.24
* Sample A, 2 grams, with 30 cc. of sulfuric acid.
+ Clear after 4 hours’ digestion.
t Not entirely clear after 6 hours’ digestion.
1921]
LE 13.
PAUL-BERRY: EJELDAHL NITROGEN METHOD
various reagents in the determination of protein*.
0.7 GRAM OF |0.7 GRAM OF
MERCURIC |0.5 Gram OF
MERCURIC
OXIDE OXIDE
5 GRAMS OF |10 GRAMS OF
SODIUM SODIUM
SULFATE SULFATEt
per cent per cent
eels. 45.98
beediee 45.89
46.24 46.20
46.29 46.24
46.33 46.38
46.24 46.29
too.) eee
NOL A (meri
AGES Mods 81
COPPER
SULFATE
0.5 GRAM OF
COPPER
SULFATE
5 GRAMS OF
POTASSIUM
SULFATE
0.5 GRAM OF
COPPER
SULFATE
10 GRAMS OF
POTASSIUM
SULFATE
per cent
45.24
45.06
0.5 GRAM OF/0.5 GRAM OF
COPPER COPPER
SULFATE SULFATE
5 GRAMS OF |/10 GRAMS OF
SODIUM SODIUM
SULFATE SULFATE
per cent per cent
AG.24 oat:
45,9879 ||| east.
45.85 46.24
45.63 46.07
AGgBC 46.38
46:20" | eee
121
1 GRAM OF
MERCURIC
OXIDE
1 GRAM OF
COPPER
SULFATE
15 GRAMS OF
POTASSIUM
SULFATE
per cent
45.89
122 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TaB
Influence of time in connection with various
——
0.7 GRAM 0.7 GRAM 0.7 GRAM
OF OF OF
10 GRAMS 10 GRAMS 0.7 GRAM MERCURIC MERCURIC MERCURIC
TIME DIGESTED OF OF OF OXIDE OXIDE OXIDE
AFTER CLEAR POTASSIUM SODIUM MERCURIC 5 GRAMS 10 GRAMS 5 GRAMS
SULFATE SULFATE OXIDE OF OF OF
POTASSIUM POTASSIUM SODIUM
SULFATE SULFATE SULFATE
hours per cent per cent per cent per cent per cent per cent
0 SOO te ee SOLOS eal) Peery 30:58) i) ore
: PN TO all Permit aves .'|ley lB oonciey Ail Pteode555 30:08: Ihe eee
2 BOS ae ee oe 30.53 30.71 30.76 30.63
00 Yee gaan gt lt oocroe 30.63 30.76 30.63
On Fe ie) sireccees tellin te as es eee | MCN coec 30.58 30.63 30.67
Relate NEY te becca | 4 telaye ae 30.54 30.63 30.67
4 30.63 30.36 30.71 30.67 30.63 30.63
30.32 BOPA3) ll Soo 30.67 30.71 30.58
6 30.67 30.63 30.49 ae 30.80 ae
B10. te ee ea enter es olf Iechatalc o 30°30) |) acre
8 30.67 gate Some ae 30.58 Sette
Hai cieiey » PARP bee Byatt en] Beri teen (ph Boveieeete 30.89 Bbo00
10 BLO AES PN Soeids 30/58) Sai isan: 30:67 | areas
as S062) tea ts Aol.) hs. Ree |? ke ehocrs 30:67) Ih eee
ZO) $2 Bethe oa ee sans se emnin| bay Ya Seeger [Pi Be Doves erate 3071: jl seer
Re |e? ee tae lh eee os iW singe) i wOOr aE 30:67 sil) Germs
* Sample B, 2 grams, with 30 cc. of sulfuric acid.
From a study of Tables 13 and 14, it will be seen that when 10 grams
of either potassium or sodium sulfate were used, maximum results were
reached in 6 hours, but with 5 grams an excessive time was required to
clear up the solution and maximum results were not reached in 6 hours’
additional digestion. With mercury alone the results were not satisfactory
since approximately 10 hours were required to complete the digestion.
However, when both mercury and potassium sulfate were used maximum
results were obtained with 2 hours’ digestion after clearing. It will be
noted that there appears to be little difference between 5 grams and 10
grams of sulfate when used with mercury. When copper sulfate alone
is used, maximum results were not reached even after 10 hours’ digestion.
But with both copper sulfate and potassium sulfate maximum results
were reached after 6 hours. Mercury is much more efficient than copper,
as when mercury alone was used maximum results were reached in 10
hours, while with copper alone this was not the case. This conclusion is
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 123
LE 14.
reagents in the determination of protein*.
z K = 1 GRAM OF
0.7 GRAM 0.5 GRAM 0.5 GRAM 0.5 GRAM 0.5 GRAM MERCURIC
OF oF oF OF oF ene
MERCURIC 0.5 Gram COPPER COPPER COPPER COPPER TiGniscor
OXIDE We SULFATE SULFATE SULFATE SULFATE GOPPER
10 GRAMS Senos 5 GRAMS 10 GRAMS 5 GRAMS 10 Grams Sain
oF See oF or oF OF 15 GREEN Or
SODIUM POTASSIUM POTASSIUM SODIUM SODIUM SOTiSaroar
SULFATE SULFATE SULFATE SULFATE SULFATE sori
per cent per cent per cent per cent per cent per cent per cent
30.28 PUTO aI) Gerieteee PY || wacoon sil pacoe 30.50
BUSOU | Ns solrerton Wl!" Gaaes PANE || Aanesc. || “pedo |) Sasac
30.59 PEL N| Seeds BEM) |i. seGent |) <- Sdene 30.71
SUSE I Gasca || Meee ROT ashes Sl Geegag Il! wosscc
Bcf), odie vdageny ll “leeecoar ll eeeee nt (e tace aoa | Menem eacesetse
DUS Meeciss WP ecsoe ce Wl fice [Mi wacee Ml sseex |) seeds
37000 30.10 ert risfs 30.67 area pce 0b 30.75
Socbe | |/PBeaaelt ya!” Gadass 30.71 nods abade
aston || bee UI apie 30.67 Sone Anode Soo ne
shee 29.97 30.22 30.71 30.01 30.71 30.71
coco, |). Sepag 30.54 30.80 30.32 oat a6 Jeac8
c&cca. | |RRRE Ror |" aeeRe 30.68 SNORE ereters Sande
soses. |) “Somee 30.63 30.49 30.41 sodne sO00C
sscoo 6 || oe 30.49 30.63 30.58 socod Sosc0
sesnE 29.27 onde 30.63 SaaS Fo8e 30.71
=coco || eeeeo MN | “saees 30.89 Jonod Sno bo Soo08
soouo |) peeogm al degese 30.76 prateyete SOF St Aoaca
also borne out by the fact that with mercury and potassium sulfate
maximum results are obtained in from 2 to 3 hours, while with copper
sulfate and potassium sulfate they were reached in 5 to 6 hours. Then
again, a longer time is required to clear up the solution when copper sul-
fate is used than when mercury is used. It would appear that potassium
sulfate is a little more efficient than sodium sulfate, as with 5 grams of
the former the solution was clear in 4 hours, while with 5 grams of sodium
sulfate the solution was not entirely clear after 6 hours. From the
results obtained the conclusion must be drawn that the most efficient
combination is mercury and 5 to 10 grams of either potassium or sodium
sulfate. One objection sometimes raised to the use of mercury is its
greater cost over copper sulfate, but it would seem that this objection
is completely offset by the time consumed in the case of the latter. There
is no advantage in the combination of mercury and copper sulfate as
directed in the Kjeldahl-Gunning-Arnold method.
124 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
TABLE 15.
Effect of mercuric oxide* used in the determination of protein.
SAMPLE A SAMPLE B
a a Hours digested after clear Hours digested after clear
USED TO CLEAR
2 3 4 2 3 4
gram hours per cent per cent per cent per cent per cent per cent
0.0 2 AD OLA feranster 45.76 OS I acase 30.63
cles MWS BA was 46.18 BONA |) oleic. 4 30.32
0.1 1j 45.68 | 45.89 46.29 30.36 30.19 30.63
45.94 46.03 46.20 SUSY WP ao oee 30.71
0.2 13 45.98 46.20 46.16 30.49 30.54 30.63
AGT). WW ganas 46.16 SOFC 1s eee 30.58
see) {NM apes 46.29 sation Signe 30.63
0.3 1 45.94 46.20 46.29 30.58 30.54 30.76
46.03 AG29 53, oseitee BUST gaan. lls cose
0.5 1 46.20 46.24 46.33 30.49 30.63 30.63
46.29 AG Some raeecee 30.45 30:65) ||) eee
0.7 1 46.29 46.33 46.24 30.76 30.67 30.59
46.33 46.33 46.29 30.76 30.71 30.80
si ceseex ald | barstiaavake 46.29 30.58 30.76 30.71
1.0 1 46.16 46.16 46.38 30.55 30.49 30.71
te le Gooaay ip noc Be oioaae || ooccs
Node hisaedeo t||t mob ot > 30.55 Fiver Boon
* Digested 2 grams of sample with 30 cc. of sulfuric acid and 10 grams of potassium sulfate.
The figures in Table 15 show that from 0.5 to 0.7 gram of mercuric
oxide is the proper amount to use. In fact, 0.3 gram gives maximum
results with 3 hours’ digestion after clear, while 0.5 gram or over gives
the maximum in 2 hours. There certainly is nothing to be gained by
the use of more than 0.7 gram.
1921) PAUL-BERRY: KJELDAHL NITROGEN METHOD 125
Taste 16.
Effect of copper sulfate* used in the determination of protein.
COPPER TIME
SULFATE REQUIRED
USED TO CLEAR
258
gram hours
0.1 13
0.3 res
0.5 res
1.0 re
SAMPLE A
Hours digested after clear
5 6
per cent per cent
46.38 46.29
46.16 46.24
AgSa6 46.23
45.41 46.24
46.20 46.20
45.37 45.85
45.54 46.33
46.38 46.33
46.38 46.20
awe bic 46.16
45.98 46.38
46.16 46.38
SAMPLE B
Hours digested after clear
6 7
per cent per cent
30.67 30.63
30.71 30.71
30.42 30.54
30.63 30.80
30158 {li saesce
30.63 30.49
* Digested 2 grams of sample with 30 cc. of sulfuric acid and 10 grams of potassium sulfate.
From Table 16 it will be seen that the quantity of copper sulfate used
has very little influence.
TABLE 17.
Effect of quantity of sample* used in the determination®of protein.
0.5-GRAM SAMPLE 1-GRAM SAMPLE 2-GRAM SAMPLE
TIME
DIGESTED
AFTER CLEAR ! Sample A | SampleB || SampleA | SampleB || Sample A | Sample B
hours per cent per cent per cent per cent per cent per cent
1 46.28 46.11 30.63
46.20 46.11 30.71
2 46.38 30.28 46.38 30.63 46.29 30.76
46.03 30.45 46.29 . 30.71 46.33 30.58
3 46.73 30.45 46.38 30.71 46.33 30.67
46.55 Oe 46.29 30.71 46.33 30.71
* Digested with 30 ce. of sulfuric acid, 0.7 gram of mercuric oxide and 10 grams of potassium sulfate.
The figures in Table 17 were obtained by using 0.5-, 1- and 2-gram
samples. Maximum results were reached with a slightly shorter time
of digestion with the smaller amount of sample, but much greater diffi-
126 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
culty was experienced in getting concordant results. This is undoubtedly
due to the fact that the smaller the sample weighed, the greater the
difficulty of obtaining a representative sample, and the multiplication
of slight unavoidable errors. Everything considered, it seems that a
2-gram sample of cottonseed meal and similar substances is preferable
to other amounts.
TABLE 18.
Protein obtained by using the details found to be most desirable*.
0.7 GRAM OF MERCURIC OXIDE DIGESTED 0.3 GRAM OF COPPER SULFATE DIGESTED
3 HOURS AFTER CLEAR 6 HOURS AFTER CLEAR
Sample A Sample B Sample A Sample B
per cent per cent per cent per cent
46.24 30.58 46.11 30.49
46.24 30.54 46.20 30.49
46.24 30.54 46.16 30.58
46.16 30.41 46.07 30.58
46.03 30.49 46.20 30.54
46.11 30.51 46.03 30.58
46.24 30.41 46.11 30.62
46.03 30.41 45.94 30.45
46.20 30.58 45.94 30.58
46.16 30.41 46.11 30.36
46.24 30.45 46.24 30.36
46.03 30.45 46.11 30.41
Ay... ..46.16 30.48 46.09 30.50
Min. ...46.03 30.41 45.94 30.41
Max.. ..46.24 30.58 46.24 30.62
* Digested 2 grams of sample with 30 ce. of sulfuric acid and 10 grams of potassium sulfate.
METHOD.
After due consideration of the figures given in these tables, together
with the experience gained during this investigation, the writers con-
sider the following details to be such that if carefully followed in every
respect no difficulty should be experienced in getting satisfactory results
when working upon cottonseed meal or similar substances by individual
or different analysts:
Grind the sample to such a fineness that it will pass through a 30-mesh sieve, or a
sieve having round 1 mm. openings. Place 2 grams of this thoroughly mixed sample
in a 500 ce. digestion flask, add 0.5-0.7 gram of mercuric oxide or its equivalent of
metallic mercury, 5-10 grams of potassium or sodium sulfate and shake the flask until
the contents are well mixed. Add 30 ce. of sulfuric acid and again shake until the acid
and dry material in the flask are perfectly homogeneous. This mixture should be prac-
tically free from lumps. Place the flask in an inclined position, using a guard having
a hole for the flask of such a size that the flask can never be exposed to the bare flame
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 127
above the acid at any time during digestion, and heat with a very low flame until froth-
ing ceases. Gradually increase the flame until the liquid boils briskly, using a flame
with the air so regulated that it gives a sharp-pointed blue flame. Continue this heat
until the solution is entirely clear. This should require 1-1} hours. Decrease the
heat until the liquid boils gently and continue this digestion for 3 hours. Allow to cool,
add 230 cc. of water and 20 cc. of 4% potassium sulfide. Shake, and add an ex-
cess of saturated sodium hydroxide solution (50-60 cc.), allowing it to run down the side
of the flask so that it does not mix with the acid solution. Add a few pieces of granu-
lated zinc and connect the flask with the distillation apparatus. This apparatus must
be equipped with the most efficient form of Kjeldahl connecting bulb, inserted between
distillation flask and condenser. Mix the contents by shaking, and distil about 150 cc.
- into very accurately measured standard acid, using an excess of acid necessary to hold
all the ammonia. ,
If it is desired to use copper sulfate in place of mercuric oxide, substitute 0.3-0.5
gram of copper sulfate for the mercury and digest for 6 hours after the solution becomes
clear and omit the potassium sulfide.
EXAMINATION OF OTHER PRODUCTS.
To ascertain the length of time necessary to digest in order to obtain
the maximum results in various other substances, determinations were
made on wheat flour, powdered milk, gelatin, egg-albumin, and tankage.
TABLE 19.
Time required for digestion of flour.
2-GRAM SAMPLE, 30 CC. OF SULFURIC ACID, MERCURIC OXIDE COPPER SULFATE
10 GRAMS OF POTASSIUM SULFATE USED USED
Time digested after clear Protein (N X 5.70)
hours per cent per cent
3 HO‘09; = es. arava
1 10529 ee |e nt raeter
TOO eaters
2 LOZORE Sis
10.13 10.17
3 10.25 10.37
10.20 10.21
cy)” ere |e) Ri ae a 10.29
Sooo 10.21
OMwrO! ) wey gy Wie OF Sesvcaxs 10.29
Sao 10.21
J28 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 7
TABLE 20.
Time required for digestion of powdered milk.
2-GRAM SAMPLE, 30 cc. OF SULFURIC ACID, MERCURIC OXIDE | COPPER SULFATE
10 GRAMS OF POTASSIUM SULFATE USED USED
Time digested after clear Protein (N X 6.38)
hours per cent per cent
} EVA eal i lil Me.
32.83 eine
1 S280 me i oe a iecees
2 32.83 32.38
BASS ee ET MAT EY eee
3 32.87 32.87
32.69 32.83
vege) Pe gh ey en awe el SE oe 32.65
cote 32.74
tae Tie 6 a rlitoos cs 32.74
Roses 32.83
TABLE 21.
Time required for digestion of gelatin.
2-GRAM SAMPLE, 30 CC. OF SULFURIC ACID, MERCURIC OXIDE COPPER SULFATE
10 GRAMS OF POTASSIUM SULFATE USED USED
Time digested after clear Protein (N X 5.55)
hours per cent per cent
2 85:39") 1 eee
85:35) | a eee
3 85:35: 1) flee ee
4 85:43 097 Pah RR Reyes
Soke WAV Boe aatnceys
i ie eee: |e Cnn 85.04
eyovoneie 85.09
CT is abet Becton. 85.47
Joeo0e 85.43
1921] PAUL-BERRY: KJELDAHL NITROGEN METHOD 129
TABLE 22.
Time required for digestion of egg-albumin.
2-GRAM SAMPLE, 30 CC. OF SULFURIC ACID, MERCURIC OXIDE COPPER SULFATE
10 GRAMS OF POTASSIUM SULFATE USED USED
Time digested after clear Protein (N X 6.25)
hours per cent per cent
3 Gai; 8 Seas
THOS Pe Pe Soooe
1 Ua SU area ce
Uy I a's
rane USL ee am | eis
WURS 6 Ab Boas
3 ae ee || ee.
“iiss | | Ss Geaeis
CS Ee ae let Pe Sear ic 76.91
Sriatte 76.83
Le eT ee ee eee 77.39
Sd500 77.09
ite le ee Pc Z 77.13
Saodc 77.04
(rs) Pe ae a eer ic 77.35
Rone 77.31
TABLE 23.
Time required for digestion of tankage.
2-GRAM SAMPLE, 30 CC. OF SULFURIC ACID, MERCURIC OXIDE COPPER SULFATE
10 GRAMS OF POTASSIUM SULFATE USED USED
Time digested after clear Protein (N X 6.25)
hours per cent per cent
3 40353 eee, I Ne eicrcne
SOTAAE mares
4 AO: Cs lt pee hs es
ge Gee |) | eeisonce
5 CULE wn eed | Ase
49SOF— ee ectente
ery Pee ee ees 48.83
Bapoc 48.74
de dst 49.25
Stes 49.39
2) ee ee ore a 49.66
ese 49.74
ORS ft | ee 49.88
130 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
From Tables 19 to 23, it will be seen that 1-hour digestion with mer-
cury and 2 hours with copper sulfate is sufficient in the case of flour,
3 hour and 2 hours in the case of powdered milk, 2 and 6 hours for gela-
tin, 1 and 5 hours in the case of egg-albumin, and 4 and 8 hours for
tankage.
EFFECT OF NITROUS FUMES.
So far as known, there has never been anything published regarding
the effect of nitrates or nitric oxides introduced at different stages dur-
ing the digestion. For the purpose of studying this question, the follow-
ing experiments were conducted.
TABLE 24.
Effect of introduction of nitrates or nitric oxides at beginning of digestion*.
AMMONIA AS AMMONIUM POTASSIUM NITRATE AMMONIA AMMONIA
SULFATE ADDED EQUIVALENT, 10 AMMONTA RECOVERED RECOVERED
ADDED
gram gram gram per cent
0.1688 0.102 0.2002 118.6
0.1688 0.051 0.1918 112.5
0.0844 0.102 0.1214 143.6
0.1688 0.034 0.1848 109.4
0.1688 0.017 0.1783 105.6
0.1688 0.010 0.1722 102.0
0.1688 0.005 0.1746 103.4
0.1688 0.102 0.2006 118.8
0.1688 0.051 0.1918 PI25
Ammonia from cot-
tonseed meal:
0.1795t 0.0336 0.2077 115.7
0.1185t 0.0336 0.1547 130.5
* Digest 30 ce. of sulfuric acid with 0.7 gram of mercuric oxide or 0.3 gram of copper sulfate, 10 grams of
potassium sulfate, and 1 gram of sugar.
+ Two grams of Sample A.
t Two grams of Sample B.
TABLE 25.
Effect of nitrates or nitric oxides introduced after solution is clear*.
AMMONIA AS
AMMONIUM SULFATE POTASSIUM NITRATE AMMONIA AMMONTA
ADDED ADDED RECOVERED RECOVERED
gram gram gram per cent
0.1688 0.1 0.1547 91.1
0.1688 0.1 0.1527 90.5
0.1688 1.07 0.0753 44.6
0.1688 1.0t 0.0712 42.2
0.1688 1.07 0.0615 36.5
0.1688 1.0+ 0.0707 41.9
2 grams of cottonseed
meal, “A” 1.0¢ 0.1224 68.2
2 grams of cottonseed
meal, “B” 1.0f 0.1022 86.2
* Digest 30 cc. of sulfuric acid with 0.7 gram of mercuric oxide or 0.3 gram of copper sulfate and 10
grams of potassium sulfate. {
+ Added 0.1 gram at intervals during digestion.
1921| PAUL-BERRY: KJELDAHL NITROGEN METHOD 131
TABLE 26.
Digestions in presence of nitric acid fumes.
SAMPLE A SAMPLE B
Protein in Protein Total Protein in Protein Total
sample found protein lost sample found protein lost
per cent per cent per cent per cent per cent per cent
46.20 43.93 4.91 30.50 26.56 12.91
Ae 43.44 5.97 svevels 25.64 15.93
37.98 17.79 EGo0 20.30 33.44
40.12 13.16 nye 21.91 28.16
32.20: 30.30 S50 23.32 23.86
35.35 23.48 aghas 24.50 19.67
31.06 32.77 550 mieyers Senos
28.57 38.16
It seems quite natural that the presence of nitrates in a sample con-
sisting largely of organic material, would, by the Kjeldahl method,
yield a higher result than would be obtained without the nitrates. This
would be expected, since the organic matter present would probably
bring about at least a partial reduction of the nitric nitrogen to ammonia.
This is well understood, and it is also known that the reduction is not
complete, but that there is a loss of nitric nitrogen. Table 24 shows this
definitely.
The question now is, what will be the result of adding nitric nitrogen
after the organic matter is fully decomposed? To answer this, the ex-
periments recorded in Table 25 were undertaken. It will be seen that
not only is the nitric nitrogen lost entirely, but there is, in addition, a
considerable loss of the organic or ammoniacal nitrogen, amounting in
one instance to as much as 58 per cent. The reaction may be essentially
10 NH; + 3 N20; = 8N. +15 H.O. Probably, especially in the presence
of organic matter, the reaction is, in fact, far more complex.
The next question was the possible effect of conducting nitrogen
determinations in the presence of nitrous fumes. The results recorded
in Table 26 were, accordingly, obtained in a hood in which there were
present large quantities of red oxides of nitrogen. Contrary to expecta-
tion, these fumes could be observed travelling down the lower side of
the neck of the flask, notwithstanding the fact that fumes were being
given off in the digestion reaction and could be seen plainly escaping
along the upper side of the neck of the flask. The results show a remark-
able loss of nitrogen, amounting to as much as 38 per cent.
This will show the extreme importance of eliminating and carefully
guarding against the presence of any nitrous fumes. No nitric acid should
ever be used in a hood where nitrogen digestions are to be made, as these
fumes have a tendency to persist, even in spite of a strong draft. This
132 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
is especially true if a lead tube is used to carry off the sulfuric acid fumes.
Usually, the necks of the digestion flasks pass through openings into
this lead tube, and sulfuric acid collects in the bottom. If, later, nitric
fumes are liberated in the hood, the condensed sulfuric acid=will tend to
retain some of these fumes. During subsequent nitrogen determinations
the heat will liberate these and they will enter the necks of the flasks
and cause discordant and erroneous results.
SUMMARY.
The interesting and important points developed in the investigation
are:
(1) The use of an efficient distillation bulb is important.
(2) The use of a guard in digestion is essential.
(3) The use of potassium permanganate is at least unnecessary.
(4) The reagents, in addition to sulfuric acid, which are most econom-
ical of time are combined potassium, or sodium sulfate, mercuric oxide
and potassium sulfide.
(5) Copper sulfate may be used in place of mercuric oxide and potas-
sium sulfide, but the time of digestion must be lengthened.
(6) The time of digestion after clearing is of prime importance, and
should be determined for each kind of substance to be examined. In
most instances 3 hours is sufficient.
(7) Nitric acid should not be used in a hood in which it is the intention
to make nitrogen digestions at a future time.
No referee on potash was appointed and no special report on this
subject was presented.
REPORT ON POTASH AVAILABILITY.
By A. G. McCatu (Agricultural Experiment Station, College Park, Md.),
Referee.
The investigation of the availability of the potassium of greensand
composted with manure and sulfur has been continued during the year
at the Maryland Agricultural Experiment Station. Reports from other
Agricultural Experiment Stations show that the official method for the
determination of potash does not give full credit for the available potash
found in the so-called treater dust and wood ashes. Haskins! called
attention to this and suggested the advisability of devising some modi-
1 J. Assoc. Official Agr. Chemists, 1920, 4: 82.
1921] SMITH: POTASSIUM FROM GREENSAND COMPOSTS 133
fication of the official method that would include not only the potash
dissolved by hot water, but also that which would be readily broken
down in the soil and thus become available to the growing plants. Be-
fore any definite conclusions can be reached, it will be necessary to make
vegetation tests with some of these materials to see if the potash that
is lightly locked up as basic compounds may not become readily available
to growing plants when incorporated with the soi]. While this question
is not so important as it was during the war period when our European
supply of potash was cut off, your referee is of the opinion that the associa-
tion should interest itself in this matter with a view to obtaining data
upon which some definite action may be taken.
RECOMMENDATIONS.
It is recommended—
(1) That the work on the availability of potash in composts, treater
dust and wood ashes be continued.
(2) That a general referee on potash be appointed to continue the
study of the perchlorate method with special reference to the moist
combustion process!, and to make a further study of the effect of using
stronger alcohol for the first washings in the official Lindo-Gladding
method with special reference to the presence of sodium salts.
POT CULTURE TESTS ON THE AVAILABILITY OF
POTASSIUM FROM GREENSAND COMPOSTS.
By A. M. Smirx (Agricultural Experiment Station, College Park, Md.).
Glauconite, commonly known as greensand, consists chiefly of the
hydrous silicate of iron, aluminium. and potassium. Because extensive
deposits of this mineral exist as outcrops and subsoil in New Jersey,
Maryland and Virginia, it was thought advisable, during the period of
potash shortage, to investigate the possible use of greensand as a fer-
tilizer.
Previous work at the Maryland Agricultura] Experiment Station?
showed that composting greensand with sulfur and organic matter for
a period of from 15 to 23 weeks changed a considerable part of the in-
soluble potassium to a form soluble in water. In this paper it is desired
to report some results of pot culture tests on the availability of the
potassium from these composts, and to present other points of chemical
interest developed during the progress of the investigation.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 373.
2 [bid., 375.
134 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
Barley was grown to maturity in a series of glazed pots, each pot
having 2800 grams of Collington sandy loam containing 0.82 per cent
of potassium. After germinating the seeds on a cheesecloth screen in
contact with a weak germinating solution, four seedlings were trans-
planted to each pot.
The treatments were planned with the following objects in view:
(1) To compare the availability and effectiveness of equal amounts
of potassium from potassium sulfate, composted greensand, and un-
treated greensand.
(2) To compare composted greensand with the uncomposted mater-
ials in the same amounts and proportion, with and without the use of
lime.
Each treatment was in duplicate. Each pot, including the controls,
received 0.5 gram of ammonium sulfate and 0.5 gram of monocalcium
phosphate. The potassium treatments are given in Table 1, the amount
in each case being equal to that contained in 0.5 gram of potassium
sulfate.
TABLE 1.
Results of pot culture tests.
CROP YIELD* SOIL ACIDITY*
POT —_—_——__——
NUMBER TREATMENT p Calcium car-
Dry weight bonate by
of tops Veitch’s method
gram p. p.m.
1 and 2 Control. 12.9 1600
3 and 4 Greensand, 4.04 grams. 13.4 2350
7 and 8 Greensand, 4.04 grams.
Sulfur, 1.35 grams; and manure, 1.35 grams. 5.0 7650
9 and 10 Greensand, 4.04 grams.
Sulfur, 1.35 grams.
Manure, 1.35 grams; and calcium car-
bonate, 5.0 grams. 16.5 3400
13 and 14 Compost, 7.57 gramsf. 0.7 11200
15 and 16 Compost, 7.57 grams}; and calcium car-
bonate, 5.0 grams. 20.9 2950
19 and 20 Potassium sulfate, 0.5 grams. 16.1 2050
21 and 22 Potassium sulfate, 0.5 grams; and calcium
carbonate, 5.0 granis. 22.4 1000
* Average of 2 pots. see ol
+ Corrected for moisture and oxidation.
These results show that under favorable conditions on a soil low in
potassium, an application of greensand alone increased the yield of
1921] SMITH: POTASSIUM FROM GREENSAND COMPOSTS 135
barley, while the treatment of lime and compost gave somewhat better
results than lime and the same materials uncomposted. Whether this
will be true after the first growing season will be shown by work in prog-
ress. An application of compost alone resulted in almost complete crop
failure, but compost and lime gave practically the same results as potas-
sium sulfate and lime. This indicates that when sufficient lime is used
the potassium from the compost is practically equal in value to potas-
sium from potassium sulfate. An interesting phase of this work is the
acidity developed by the treatment with compost.
The pot culture tests show that when lime is not applied with the com-
post the yield of barley is seriously reduced. Observations, made while
titrating to determine the water-soluble acidity of the compost, indicate
the presence of large amounts of soluble iron and aluminium. From these
indications it appears that this reduction in yield is due to an excess of
soluble iron and aluminium salts which, upon the addition of lime, are
converted into a form not injurious to barley. This is in agreement with
the work of Hartwell and Pember!; Mirasol?; Ruprecht and Morse;
and Abbott, Conner, and Smalley‘.
As compared with the acidity of the soil treated with greensand alone,
acidity determinations showed that in a single growing season the soil
acidity resulting from the application of flowers of sulfur was equivalent
to more than three times the theoretical amount of sulfuric acid that
could be formed by complete oxidation of the sulfur. This is significant
and worth keeping in mind when recommending applications of sulfur
as a plant food, or for the purpose of combating the potato-scab disease.
The pot culture tests and chemical analysis of the compost show that
the availability of the potassium in the compost is not decreased to an
appreciable extent by the addition of lime, either before or after apply-
ing the material to the soil.
How may this information be of benefit to the average farmer? Since
considerable labor is involved in making composts, it is probable that he
will prefer to make direct additions of sulfur to soils well supplied with
organic matter and total potassium. In this manner, through the pro-
cess of sulfofication, it may be possible to obtain sufficient available
potassium to meet the requirements of the usual field crops.
SUMMARY.
(1) In the growth of barley the potassium contained in greensand-
sulfur-manure compost was practically equal in availability to an equiva-
lent amount supplied in the form of potassium sulfate.
1 Soil Science, 1918, 6: 259.
; aes mee ae ages
ass. : t. Sta. Bull. 176: (1917).
* Purdue Oiiz Agr. Expt. Sta. Bull. 170: (1913).
136 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
(2) An application of lime to the compost, or to the soil treated with
the composted material, does not decrease the availability of the potas-
sium, but is essential to secure increased yields.
(3) Greensand-sulfur-manure compost, when applied to a soil of low
potassium content and deficient in organic matter, gave better yields
at the end of the first growing season than an application of the same
materials uncomposted.
A paper on ‘‘Some Results of the Determination of Potash by the
Lindo-Gladding Method Using Alcohol of Various Strengths in the
Presence of Sodium Salts’’ was presented by R. D. Caldwell and H. C.
Moore of the Armour Fertilizer Works, Atlanta, Ga.
REPORT ON INORGANIC PLANT CONSTITUENTS!.
By J. H. Mircnett (Clemson Agricultural College, Clemson College,
S. C. ), Referee.
The work was divided into two parts. W. L. Latshaw was asked to
develop a method for the determination of total phosphorus and, if
possible, a better method for the determination of sulfur in the seeds of
plants. A. J. Patten, the other associate referee, was asked to continue
the work reported in 1919? on calcium and magnesium in the ash of seeds.
RECOMMENDATIONS.
It is recommended—
(1) That further work be done on calcium and magnesium in the ash
of seeds, as recommended in 1919°.
(2) That some cooperative work be done on the colorimetric method
for the determination of manganese.
(3) That a method be devised for the determination of iron and alu-
minium in the filtrate from magnesium, as recommended in 1919°.
REPORT ON SULFUR AND PHOSPHORUS IN THE SEEDS
OF PLANTS"
By W. L. Latsnaw (Agricultural Experiment Station, Manhattan, Kans.),
Associale Referee.
The purpose of the work was twofold:
1 Presented by R. N. Brackett.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 391.
3 Tbid., 395.
1921] LATSHAW: SULFUR AND PHOSPHORUS IN PLANT SEEDS 137
First, to develop a method for the determination of total phosphorus
and, if possible, a better method for the determination of total sulfur
in the seeds of plants.
Second, to make the determination from the same or aliquot portion
of the sample.
The following material was used for analysis: soy bean meal; cotton-
seed meal; and mustard seed meal.
RESULTS OF INVESTIGATION.
‘MAGNESIUM NITRATE SOLUTION.
Twelve different concentrations of this solution were tried, each of the
samples being used for the fusions. Small amounts of sodium carbonate
were used with the magnesium nitrate to retard the oxidation. Mag-
nesium nitrate can not be recommended as an oxidizing agent for the
samples tried for the following reasons: (a) Oxidation is too vigorous
and causes mechanical loss; (b) oxidation is incomplete unless a large
amount of reagent is used, in which case the mechanical loss is propor-
tionally increased.
CALCIUM NITRATE SOLUTION.
Results with this reagent were similar to those with magnesium nitrate.
FUSION MIXTURE.
Sodium carbonate, 210 grams.
Potassium carbonate, 275 grams.
Potassium nitrate, 150 grams.
Fusions were made with the above mixture in proportions of one
of sample to ten of mixture. The oxidation was incomplete. The fusion
mixture was tried again with the oxidizing reagent in the mixture
increased to 225 grams. The results from cottonseed and soy bean
meal with this mixture were good. The oxidation was complete and the
determinations uniform. With the mustard seed, however, the oxidation
was rapid and violent, resulting in mechanical loss.
OFFICIAL METHOD.
The results with this method were fairly good, except with the mus-
tard seed meal in which case the reaction with the sodium peroxide was
violent and uncontrollable.
1 Assoc. Official Agr. Chemists, Methods. 2) Ee LPs
Mie gr. is e nd ed., 1920, 2.
138 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 1
FUSION MIXTURE.
Sodium hydroxide and potassium nitrate.
Potassium hydroxide and potassium nitrate.
These fusion mixtures were tried but proved to be unsatisfactory.
NITRIC ACID AND BROMINE.
Samples were evaporated to dryness with nitric acid and bromine
then mixed with sodium carbonate and a small amount of potassium
nitrate and ignited. This, however, was not successful.
PARR BOMB.
A Parr bomb, such as is used for the determination of sulfur in coal,
was employed with success, using sodium peroxide as an oxidizing agent
with a small amount of finely ground potassium chlorate as an acceler-
ator. Further work along this line was prevented because the bomb
available for use could not accommodate more than a 0.3-gram sample
with safety. The making of a bomb of a capacity sufficient to take care
of a 2-gram sample is under consideration and should, when properly
developed, prove a successful means of securing the complete oxidation
of the seeds of plants and offer a solution of the problem for determining
the total phosphorus and sulfur.
No report on calcium and magnesium in the ash of seeds was made
by the associate referee.
Cs
JOURNAL
OF THE
ASSOCIATION OF OFFICIAL AGRICULTURAL
CHEMISTS
Vou. V November 15, 1921 No. 2
CONTENTS
SRC IMINCs OF THE THIRTY-SIXTH ANNUAL CONVENTION,
NOVEMBER, 1920.
PAGE
Monpay—AFTERNOON Session, Continued.
Licmenilam Dang, [ay \Wo ls WonG eas ae ocecs ocbce aoc enonewebebncr co HpeEeeneeecouene 141
Eve pOnmorieAl ical Olds sme Dy PACER ESLISS: I; 4 1 Neteys) Verses mae aie ola cise eae ele 2 cle etic eretereinne 149
TRE e Gn Aone Ry EN SOR DG a eee aon coos so non EBS eSeUpemonenedcs ooboaShc 149
Reportonsynthetic Drugs, By'C. Do Wright. ©.5. 5) 9 2)..0s 062) feo ecck eee oe oes 150
Report on Methods of Analysis of Morphine, Codeine, and Diacetylmorphine (Heroine). By
(Cy. Lhe GN Gri inars Beie e Beti ecnSe aoe ote oe etaa olin ie are ee aan Late pCR Tie 150
Report on Medicinal lanta= 1b yeATnOpVICHOGVER Er ee eter. oo nec aici eiernce ore ss eels Sole ele 155
Method for the Examination of Procaine (Novocaine). By Alfred W. Hanson............ 163
Study of the Distillation Method for the Estimation of Santalol in Santal Oil. By C. W.
HRTEM. 5.4. 2 outa eeke SPDR OE Oo cd sone DD RCM Robe So OREEer ee are Se rine acitemete 166
TuEspay—MornInG SEssIon.
PRE voOscopyOllvilkewm> yy, suUlusEOrbVebi 26 ace ace. 5+ ee eine dene ce vere sales 172
Detemmination of Batin Malted Milk= By J.D. Keister. 23... 5. 22 2 nee ens eee maisiere 3 > 176
Report on Fats and Oils. By R. H. Kerr,............. SOR ee ete roar wees 178
Reponion ba kiMpal Gwen ms ya Grove o VAIS ere ee acc lose ais ove eveis Se <lotese.2 (elle ial 3 = ole 108 179
Determination of Total Carbon Dioxide in Baking Powder. By C.S. Robinson.......... 182
hepexti on) Pegs and bgeyeroducts: “By HU. Gourley. 2) siacs occ gee eee cee ete 191
Report on Coloring Matters in Foods. By W.E. Mathewson.....................-.--- 196
Report one Vietalsii HOGdS-:) SEs ys Wyk. Cuarkess 5. se so. epe sieye cele lean nyoys © aigle levers «cereus s arsine ol 219
Report on Pectin in Fruits and Fruit Products. By IDR BISbee ty ts 55 feeb 2 a5 ee oe 224
Report on Canned Foods. By W. D. Bigelow TOS Mee ee 8, Es clo Brotschsoaxs 225
Effect of the Use of Different Instruments in Making a Microscopic Examination for Mold
PENNA EELOOUCLS: 2 Es yea SLOW ALOE a yt ine oe ye tstercles cintehe creel © Sateienavenes Mats 226
ionoranygecesdentis Address, (ByiE Ws Wileys. ccc tyes eee oie nye «Sima see eee aman ere 229
Address of the Secretary of Agriculture. By E. T. Meredith........................... 238
TuEsDAY—AFTERNOON SESSION.
ie poLeou Gcrealibhoods. (By GE: Balleysr- sc.ta ce ee = See Seiten ecelein ce eeere et 241
A Note on the Polarization of Vinegars. By R. W. Balcom and E. Yanoysky............ 245
Salad Dressings and Their Analysis. By H. A. Lepper..........-.-.--00.---+-2e-e0ee 248
Report on the Determination of Shells in Cacao Products. _By W. C. Taber.............. 253
Cacao Products with Special Reference to Shell Content. By B. H. Silberberg........... 260
Report on Methods for the Examination of Cacao Butter. By W.F. Baughman.......... 263
BEBGLUP Is OOLEE MEL NE LIeTA Lepper cs. vg.) sees ae Seles oc okie da ac cd seteiga eo kere 267
Robusta Coffee. By Arno Viehoever ‘and H. A. Whe Pereira irs 2 nists cvaa)s cpercrassk actayaloretebegs 274
Report on Tea. By E. M. Bailey...................-.-. SSO ROR er een; eae 288
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FIRST DAY.
MONDAY—AFTERNOON SESSION.—Continued.
DRUG SECTION.
REPORT ON DRUGS.
By G. W. Hoover (U. S. Food and Drug Inspection Station, Transpor-
tation Building, Chicago, IIl.), Referee.
The referee has made a partial review of the literature and desires to
present to the association methods of analysis for drugs that have been
published, which, in the opinion of the referee, are desirable for study
with a view to their adoption as tentative or official. In the selection of
published methods, consideration has been given, in general, to two
important phases:
(1) The relative importance of drugs for which no tentative or official
method exists.
(2) The selection of such methods of analysis for important drugs
as give most promise of being satisfactory.
Brief abstracts of articles are submitted which contain methods for
the examination of acetylsalicylic acid, phenolphthalein, camphor and
camphor preparations, mercurous chloride, mercuric chloride, mercuric
iodide, papain and turpentine. Innumerable methods of analysis and
tests for drugs have been published. Since the plan of presenting pub-
lished methods of analysis for drugs for study is an innovation, it seems
desirable to proceed gradually to avoid making the plan cumbersome
and unwieldy.
With this in mind, only a limited number of methods have been
selected for presentation at this meeting.
The following are abstracts of the methods referred to and references
to the literature where the different articles have been published:
ACETYLSALICYLIC ACID.
This association has no tentative or official method for the examina-
tion of acetylsalicylic acid. The prominence of this drug has commanded
the attention of various pharmaceutical chemists and during the last
few years several very interesting and excellent articles have been pub-
lished upon the subject. An attempt has been made to select and review
141
142 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
those articles which are believed to be of most use to a referee studying
the subject of acetylsalicylic acid.
H. L. Schulz, in collaboration with C. K. Glycart, A. W. Hanson, and
A. E. Stevenson, in an article entitled, ‘‘ Methods of Analysis of Acetyl-
salicylic Acid and Adulterants’’!, gives the results of the analysis of
samples of acetylsalicylic acid found upon the market. Qualitative tests
are outlined for acetylsalicylic acid, free salicylic acid, salol, acetanilid,
acetphenetidin, sugars, starch, and salts. A quantitative method for
acetylsalicylic acid is also outlined. In this method, the acidity of acetyl-
salicylic acid is determined by dissolving the sample in 95 per cent
alcohol, and titrating directly with 0.1N potassium hydroxide. Total
acids are determined by hydrolysis with an excess of 0.1N potassium
hydroxide, and the excess of alkali titrated back with 0.1N acid. The
amount of acetylsalicylic acid is calculated by multiplying the number
of cc. of 0.1N alkali used for the second or hot titration by the factor
0.018. A method for the determination of total salicylates is also given,
which is based upon precipitation with standard iodine solution, and
calculation of the salicylates from the weight of the precipitate.
A. J. Jones published an article on ‘*‘The Purity of Commercial Aspirin
and Aspirin Tablets’’?. The author determined the acid and ester
value of the sample dissolved in alcohol by direct titration with
standard alkali before and after hydrolysis. The bromine value was
determined by hydrolyzing a weighed sample with standard alkali ona
water bath. Potassium bromide bromate reagent and hydrochloric acid
were added, followed by sodium iodide, and the liberated iodine
titrated with 0.1N sodium thiosulfate. The method was checked on
pure salicylic acid.
In testing for free salicylic acid, 1 per cent ferric ammonium sulfate
was used. The author states that both acetylsalicylic acid and alcohol
have some effect on the color produced.
Paul N. Leech made a careful study of the physical and chemical
properties of pure acetylsalicylic acid’, and discussed the results of
the examination of samples of various manufacturers. Especial attention
was given to the determination of the melting point of this chemical.
A. Nutter Smith‘ did some very extensive work on a method for the
determination of the extent of decomposition, especially with regard to
the liberation of acetic acid. The phases of the subject that were taken
up by him were studied very carefully, and the following summary is
given:
(1) A new and accurate method of estimating free acetic acid in acetylsalicylic
acid is described.
1 J. Am. Pharm, Assoc., 1918, 7: 33.
2Am. J. Pharm., 1919, 91: 461. ;
3 J. Ind. Eng. Chem., 1918, 10: 288; Rept. Chem. Lab. Am. Med. Assoc., 1919, 12: 62.
‘ Pharm. J.. 1920, 105: (4th ser., 51:), 90.
1921] HOOVER: REPORT ON DRUGS 143
(2) It has been found that in the majority of instances free salicylic and acetic
acids balance substantially; when acetic acid is in excess it is probably due to retention
of acid due to incomplete purification, and when deficient it intimates that acetic acid
has volatilized.
(3) The B. P. (British Pharmacopeeia) coloration test for free salicylic acid is not
very sensitive, and can easily be masked in a manner not so easily detected.
(4) Salts of acetylsalicylic acid appear to hydrolyze into free salicylic acid and
an acetate of the base, and it is certain that they possess no advantage whatever over
the acid as found on the market today, containing free salicylic acid in amount suffi-
cient to produce the gastric disturbance usually attributed to the salicylates, the alleged
objection which caused the latter to be superseded by the acetyl ester. It is not im-
probable that any therapeutic virtue or favor which the salts may possess over the
acid is owing to the fixation of the acid on hydrolysis.
(5) Standards of 0.1 per cent free salicylic and 0.05 per cent free acetic acid are
suggested for the drug, and double these amounts for tablets. If these limits are ex-
ceeded the controlling analyst would be justified in “‘failing’’ the sample, especially
if recently prepared. It is well known that aspirin tablets on keeping tend to show an
increase in the amounts of free acids present.
METHODS FOR THE DETERMINATION OF PHENOLPHTHALEIN.
A. Mirkin published ‘‘A New Method for the Determination of Phe-
rolphthalein’”!, which is based on the principle that phenolphthalein
refluxed with hydroxylamine in an alkaline alcoholic solution is con-
verted into its oxime. The method is similar to that used in the deter-
mination of camphor in which the excess of hydroxylamine is titrated.
Complete details of the method and the necessary calculations are
described. Mirkin states that accurate results have been obtained by
his method.
Samuel Palkin published an article on ‘‘The Behavior of Phenol-
phthalein with Iodine and a Method for the Determination of Phenol-
phthalein’’*. Palkin’s brief description of this method follows:
A method has been devised for the accurate quantitative determination of phenol-
phthalein with a special adaptation to its medicinal preparations. This method is based
on the quantitative yield of tetraiodophenolphthalein, when a solution containing
phenolphthalein and iodine is alternately made alkaline to complete solution, and
acid to complete precipitation, at a low temperature. The tetraiodophenolphthalein
is determined by extraction with acetone-chloroform mixture, applying the usual
method of immiscible solvents. -
Palkin submits the results of analysis obtained by this method.
METHODS FOR THE ASSAY OF CAMPHOR.
Several methods have been devised for the examination of camphor
and preparations of camphor. Apparently, no single method has been
given particular preference by pharmaceutical chemists. It seems de-
1 Am. J. Pharm., 1914, 86: 307.
2 J. Ind. Eng. Chem., 1920, 12: 768.
144 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
sirable to study the methods that have given most promise by workers
in the pharmaceutical field.
H.C. Fuller outlined a procedure for ‘* The Determination of Camphor’”
which was based on Walther’s carvone estimation and previous work of
Nelson.
KE. K. Nelson described a method for the determination of camphor?
which depends upon the principle that camphor forms a well-defined
oxime. The steps in the procedure are as follows:
A measured volume of an alcoholic solution of camphor, to which sodium bicar-
bonate is added, is refluxed with a standard solution of hydroxylamine. Hydrochloric
acid is added to form hydroxylamine hydrochloride. Methyl orange is added and the
mineral acid neutralized with normal alkali. Then phenolphthalein is added and the
hydroxylamine hydrochloride titrated with 0.1N alkali. A blank is conducted and the
difference in titrations represents the hydroxylamine converted into camphor oxime.
POLARISCOPIC METHODS.
A. T. Collins published *‘ A Method for Assaying Spirits of Camphor’”
which directs that polarization be made in a 200 mm. tube, correcting for
temperature (above or below 20°C.). He states that the rotation of
different camphors varies. However, in the preparation of a control by
evaporating and subliming a separate portion of the same sample, errors
are eliminated. The presence of sugar is also accounted for in the non-
volatile residue from sublimation. The method is claimed to be accurate.
Edwin Dowzard outlined a method for ‘‘ The Determination of Cam-
phor in Tablets and Pills’’*, which involves distillation with steam in a
special apparatus to prevent blocking of camphor in the condenser
tube. The apparatus is shown by cut. Results are calculated by polar-
izing the camphor, extracted with the aid of benzol, and comparing
with a control. Accurate results are claimed by the author.
A number of years ago E. K. Nelson outlined a method for the deter-
mination of camphor in pills and tablets, which was never published.
The method involves steam distillation. Blocking in the condenser
tube is prevented by admitting a few drops of chloroform in the steam
generator. The camphor is extracted from the distillate with chloroform,
made to definite volume and polarized. At the same time, a 10 per cent
solution of camphor and chloroform is polarized, and from the data
obtained the amount of camphor in the sample is calculated.
METHODS FOR THE DETERMINATION OF CALOMEL IN -TABLETS.
In 1914, L. F. Kebler published an article on ‘‘The Tablet Industry—
Its Evolution and Present Status’’*. This article contains methods for
1U. S. Bur. Chem. Cire. 77: ae
2J. Ind. Eng. Chem., 1912, 4: 514
*Ibid., 1914, 6: 489.
Ay Am. Pharm, Assoc., 1914, 3: 1062.
1921] HOOVER: REPORT ON DRUGS 145
the analysis of calomel in tablets. Three methods for the determination
of calomel are outlined, and the following are some of the essential points
of each method:
Method A.—A weighed sample is disintegrated with potassium iodide. To this mixture
is added standardized iodine solution. The excess of iodine is titrated with thiosulfate.
Formulas showing the reaction and factor for calculation are given.
Method B.—This is a method by difference. The tablets are distintegrated in water,
filtered upon a Gooch, and dried. The calomel is then volatilized over a Bunsen flame,
and the amount of mercuric chloride in the tablets is calculated from the difference
in-weighings before and after volatilization.
Method C.—This is an indirect method. The sample of calomel is treated with so-
dium hydroxide, thus forming insoluble compounds of mercury (chiefly mercuric oxide)
and sodium chloride. The chlorine is titrated with silver nitrate solution in the usual
way. Formulas showing the reaction and factors for calculations are given.
In 1916, D. K. Strickland, in his article on ‘‘Laboratory Notes on the
Standardization of the Mercurials’”!, essentially repeated the work pub-
lished by Kebler. Strickland reports that the method in which the calomel
is volatilized and calculations made from weighings before and after
volatilization gives the most satisfactory results. The other two methods
appear to have given low results, according to Strickland’s comments.
METHODS FOR THE ASSAY OF MERCURIC CHLORIDE TABLETS.
R. M. Chapin, in his article on ‘‘The Assay of Mercuric Chloride
Tablets’ ’*, found that the method proposed by Rupp, modified by Smith,
also modified and adopted by the German Pharmacopeeia, gave good
results with solutions of pure mercuric chloride. However, it was not
applicable to commercial tablets or mixtures of mercuric and ammonium
chlorides. The method of Rupp involved: (1) Reduction to metallic
mercury by formaldehyde in alkaline solution in the presence of potas-
sium iodide; (2) a solution of the precipitated mercury in excess of
standard iodine solution after acidification with acetic acid; (3) titra-
tion of excess of iodine with sodium thiosulfate.
The author modified the method in the following respects: (1) The
volume of liquid was increased by adding 75 cc. of water. This was found
necessary to prevent the interference of hexamethyleneamine com-
pounds and to prevent abnormalities in the presence of ammonium
chloride; (2) the amount of potassium iodide was increased consider-
ably to avoid the formation of a mercuric ammonium compound; (3)
the time allowed for the reduction to metallic mercury was extended;
(4) provision was made for running a blank against the reagents, especial-
ly to determine iodine-consuming materials known to be in formaldehyde.
The work by D. K. Strickland upon mercurials! reports results ob-
1 J. Ind. Eng. Chem., 1916, 8: 253.
2 Am. J. Pharm., 1914, 86: 1.
146 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
tained by the unmodified Rupp method. In the work reported by Keb-
ler! essentially the original Rupp method is outlined for the determination
of mercuric chloride. Accurate results are claimed for the modified method
as published by Chapin.
Strickland found the original Rupp method satisfactory for hypoder-
mic tablets, compressed tablets and pills. It is assumed that these prep-
arations did not contain such interfering substances as referred to by
Chapin.
Kebler and Strickland both outline the usual gravimetric method of
determining mercury by precipitation with hydrogen sulfide. Strick-
land comments that the mercuric sulfide method has a tendency to give
high results.
METHODS FOR THE ASSAY OF MERCURIC IODIDE.
A. W. Bender in an article on ‘‘The Determination of Mercuric Iodide
in Tablets’’? states that while assaying tablet triturates for mercuric
iodide he found difficulty, due mainly to other ingredients, such as terra
alba, potato starch, and gelatin. The difficulty was overcome and ac-
curate results secured by (1) digesting the tablets in hydrochloric acid
in the presence of potassium chlorate; (2) precipitating mercury as
sulfide with hydrogen sulfide in ammoniacal solution. Obviously, if the
method is accurate, the sample must be free from other metals that may
be precipitated with hydrogen sulfide in ammoniacal solution. The author
claims the method is accurate and results of analyses and factors for cal-
culations are given.
Strickland’ reports upon determinations of mercuric iodide as follows:
The method described under V (A) (original Rupp method for mercuric chloride)
was successfully used for the determination of mercuric biniodide. Before applying
it to various products it was tried out upon known quantities in the presence of varied
amounts of sugar of milk. It was found that the sugar did not affect the result. Other
factors in the reaction were varied. Thus it was observed that the time which the
solution stood after alkali and formaldehyde were added was important. The most
important factor, however, is the alkalinity of the solution. Unless there is a consider-
able excess of alkali present the mercury is not precipitated quantitatively; 30 minutes
is the time required.
METHODS OF ASSAY OF PAPAIN.
F. W. Heyl, C. R. Caryl and J. F. Staley published an article on the
‘*Standardization of Commercial Papain’’*. They experimented with
different solutions for the purpose of ascertaining the media which gave
the most satisfactory digestion. The experimental work was also con-
1 J. Am. Pharm. Assoc., 1914, 3: 1062.
2 J. Ind. Eng. Chem., 1914, 6: 753.
3 Tbid., 1916, 8: 253.
*Am. J. Pharm., 1914, 86: 542.
1921] HOOVER: REPORT ON DRUGS 147
trolled so as to exclude other ferments, such as pepsin. The authors
discussed the meaning of the term ‘‘Papain’’ and reviewed salient points
in methods of Graber, North, Rippetoe, Adams and Shelly. The follow-
ing is asummary given by the authors:
1. In these digestions with pawpaw juice it has again been shown that the diges-
tion proceeds rapidly at 80° to 100°C. This characteristic property can be utilized for
the standardization of commercial papain samples.
2. Under the conditions outlined above, dried pawpaw juice should be capable
of dissolving at 80° to 100°C. not less than 40 per cent of the egg-albumin taken.
3. No samples of “‘papain’’ were found on the market which had a higher digestive
activity than the samples of dried pawpaw latex under the conditions employed.
4. Since the use of the term “papain’’ has given rise to the conditions pointed out
in this paper, we are inclined to the view that papain products ought to be marketed
as “dried pawpaw juice”, and that only a lower limit of digestive strength should be
stated in defining a standard for it. A definition proposed upon this basis might be
stated as follows: Dried pawpaw juice is the dried albuminous exudate of the fruit of
Carica Papaya L. (Fam. Papayacee), free from starch, sugars, and diluents, and con-
tains a proteolytic enzyme or enzymes. When assayed by the method above! it has
the power of digesting at 80° to 100° C. not less than 40 per cent of the unaltered egg-
white protein.
5. Of twenty-six samples studied, seven represented the undiluted dried latex,
fifteen contained starch in amounts varying from 15 per cent to 58 per cent, while
three were diluted with sugar and one with dextrin. Four samples showed a high
digestive strength under conditions favorable for pepsin digestion. On the basis of
the standard proposed above, twelve samples, or 46 per cent, have been diluted to
such an extent that their digestive strength is below a very reasonable requirement.
VY. K. Chesnut made a ‘“‘Report on Papain’’ in 19162, Chesnut’s
work was upon authentic samples of papaya latex. He used uncoagulated
casein prepared by the Hammerstein method to measure the proteo-
lytic activity of the papain samples. The extent of the cleavage was
measured with the polariscope. The great advantage of this method
is the definiteness of the hydrogen-ion concentration. It is important
to have the hydrogen-ion concentration within certain narrow limits,
as the activity of the papain is much less above or below the optimum
concentration.
Digestion requires 30 minutes. The unchanged protein is precipitated
and filtered off. The filtrate is polarized in a 200 mm. tube to an accuracy
of 0.01° to 0.02°. The amount of rotation is the measure of activity of
enzyme. The rotation is nearly parallel to the amount of protein dis-
solved when small amounts of latex are used, but is not parallel when
large amounts are used. This shows that the papain enzyme splits up
the protein in certain ways, which are not shown by the amount of
unchanged protein left.
The author states ‘the method here given is a comparatively simple
1 Am. J. Pharm., 1914, 86: 545.
2 J. Assoc. Official Agr. Chemists, 1920, 3: 387.
148 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
one, very well adapted for research and seems well adapted for the assay
of papain, especially where adulteration with other enzymes is suspected’ ’,
METHOD FOR THE DETECTION OF MINERAL OILS IN TURPENTINE.
A tentative method for the detection of mineral oil in turpentine is
included in the methods of analysis of this association'. This method is
based upon polymerization with fuming sulfuric acid.
A. E. Paul published an article on ‘‘ Turpentine and Its Adulterants’”
which contains a method for the detection of mineral oil, based upon
partial polymerization with sulfuric acid, and decomposition of the
residue with fuming nitric acid. The following is the author’s comment
relating thereto:
The modification, or rather the combination, of old methods, employed by the
writer with entire success, is comparatively easy, is safe and rapid, includes all the
possible fractions of petroleum products, and gives almost quantitative results, except
in the case of very light naphtha, which, to the writer’s knowledge, is never employed
for the purpose of adulteration. Eyen in this case as much as 50 per cent of the amount
present is readily separated, and as little as 1 per cent of added ordinary mineral prod-
uct may be determined with certainty.
Data are submitted in support of the author’s claim for the reliability
of the method.
RECOMMENDATIONS.
It is recommended—
(1) That an associate referee be appointed to study the methods for
the examination of acetylsalicylic acid, reported herein or that may be
elsewhere available, for the purpose of selecting or developing the most
satisfactory method or methods of analysis.
(2) That an associate referee be appointed to study the methods for
the examination of phenolphthalein, reported herein or that may be
elsewhere available, for the purpose of selecting or developing a satis-
factory method or methods of analysis.
(3) That an associate referee be appointed to study the methods for
the examination of camphor and camphor preparations, reported here-
in or that may be elsewhere available, for the purpose of selecting or
developing a satisfactory method or methods of analysis.
(4) That an associate referee be appointed to study the methods
for the examination of mercurous chloride, mercuric chloride and mer-
curic iodide, reported herein or that may be elsewhere available, for the
purpose of selecting or developing satisfactory methods of analysis.
(5) That an associate referee be appointed to study the methods for
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 306.
2 J. Ind. Eng. Chem., 1909, 1: 27.
1921] EMERY: REPORT ON ARSENICALS 149
the detection of mineral oils in turpentine, herein outlined, and any
method or methods that may be elsewhere available, for the purpose of
selecting or developing additional methods for the detection of mineral
oils in turpentine.
(6) That an associate referee be appointed to study the methods of
examination of papain, reported herein or that may be elsewhere avail-
able, for the purpose of selecting or developing satisfactory methods of
analysis.
The writer wishes to acknowledge the kind assistance and interest
of A. E. Paul, C. K. Glycart, A. W. Hanson, J. H. Bornmann, H. O.
Moraw, F. W. Heyl, and S. Palkin in the preparation of this report.
REPORT ON ALKALOIDS.
By A. R. Buss, Jn. (Emory University, School of Medicine, Emory
University, Ga.), Associale Referee.
In harmony with recommendations made at the 1919 meeting!, sam-
ples were sent to collaborators, with instructions for their analysis, but
the work has not sufficiently progressed to warrant a detailed report
at this time. It is therefore recommended that the recommendations
made at the 1919 meeting be continued.
REPORT ON ARSENICALS.
By W. O. Emery (Bureau of Chemistry, Washington, D. C.), Associate
Referee.
Some progress can be noted in the study of methods available for the
chemical evaluation of arsenicals of the salvarsan type. The experience
of the associate referee on arsenicals with the Ewens? and Lehmann?
methods (oxidation with sulfuric and permanganic acid respectively)
indicates that both are equally effective for determining the actual arsenic
content, provided the digestion with sulfuric acid (Ewens’ method) is
carried out very slowly, and all subsequent operations in strict accordance
with the directions of the author. In point of time and simplicity of
operation, however, the method of Lehmann unquestionably possesses
considerable advantage over that of Ewens, and is therefore to be
recommended in ordinary chemical examinations of organic arsenicals.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 416.
2 J. Chem. Soc. (Trans.), 1916, 109, Il: 1255.
3 Apoth. Zlg., 1912, 27: 545.
150 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
REPORT ON SYNTHETIC DRUGS.
By C. D. Wricut (Bureau of Chemistry, Washington, D. C.), Associate
Referee.
RECOMMENDATIONS.
It is recommended—
(1) That the method for the valuation of hexamethylenetetramine
tablets! be adopted as tentative.
(2) That the method of W. O. Emery for the estimation of mono-
bromated camphor in migraine tablets? be studied cooperatively; and
that the E. O. Eaton method be studied further.
(3) That the method of 8. Palkin for the determination of phenol-
phthalein® be studied cooperatively; and that further study be made of
other methods.
REPORT ON METHODS OF ANALYSIS OF MORPHINE,
CODEINE, AND DIACETYLMORPHINE (HEROINE).
By C. K. Grycarr (U. 8. Food and Drug Inspection Station, Transpor-
tation Building, Chicago, IIl.), Associate Referee on
Alkaloids of Opium.
No specific methods for the estimation of morphine, codeine, and
diacetylmorphine (heroine) in tablets have been adopted by this associa-
tion. For a number of years, in drug inspection work, many samples of
alkaloidal salts of morphine, codeine, and heroine have been submitted
for analysis. Various methods for the analysis of these drugs have been
tried. In the course of the work an attempt has been made to prepare
specific details for their analysis. The results obtained by the methods
that have been devised were found satisfactory. Nothing new is claimed
for the methods, but they are essentially an adaptation of the work that
has been published.
MORPHINE.
The following are the reagents required, instructions for the prepara-
tion of sample, and details of the method:
REAGENTS.
(a) Alkaline salt solution—Dissolve 30 grams of sodium hydroxide in water, make
to 1 liter, add sodium chloride to saturation and filter.
(b) Chloroform-alcohol solulion.—Mix 90 ce. of chloroform with 10 ce. of alcohol.
(C) 0.02N sulfuric acid solution.
(d) 0.02N sodium hydroxide (carbonate free).
(€) Methyl red.—Dissolve 0.2 gram of methyl red in 100 ce. of alcohol.
1J. Ind. E Cah a 1918, 10: 606.
2 Thid., i919, ‘W:
§ Ibid., 1920, 12: Fee.
1921) GLYCART: REPORT ON MORPHINE, CODEINE AND HEROINE 151
PREPARATION OF SAMPLE,
Weigh separately at least 20 tablets to ascertain the variation in weight. Weigh
collectively all unbroken tablets and calculate the average weight per tablet.
Weigh and transfer directly to a small separatory funnel a number of tablets repre-
senting 2 but not more than 3 grains of the alkaloid. Record the number of tablets
used for the sample. In case the tablets contain more than j grain of alkaloid, powder
20 or more tablets, mix thoroughly and protect from moisture in a weighing bottle.
For each determination transfer to a small separatory funnel a weight of powdered
material (equal to a multiple of the average weight per tablet), representing 2 and
not more than 3 grains of the alkaloid.
SEPARATION OF ALKALOIDS OTHER THAN MORPHINE.
Alkaloids other than morphine are extracted by chloroform, while morphine remains
in the fixed alkali solution. In general, this separation is unnecessary (proceed to
morphine). When tablets are of unknown composition, or atropine and hyoscine are
present, shake the alkaline salt solution with 10 cc. portions of washed chloroform
(use ether for the separation of atropine). Transfer the clear solvent to a small beaker,
and evaporate on a steam bath. If a residue is obtained, apply the usual tests.
DETERMINATION,
Moisten the sample in a separatory funnel with 5 cc. of water. Shake gently to
disintegrate the tablets, then dissolve completely by adding 10 cc. of the alkaline salt
solution.
To the alkaline salt solution, add a small piece of litmus paper, then concentrated
hydrochloric acid, drop by drop, until neutral. Add 10 drops in excess. Then add
5 cc. of alcohol, carefully neutralize with ammonia, drop by drop, then add 5 drops in
excess. (The addition of acid, ammonia, and alcohol should be made within the limits
as directed. Ammonium chloride, which is sparingly soluble in alcohol, tends to neu-
tralize morphine when the residueisheated.) Invert theseparatory funnel and open the
stop cock to insure neutralization of residual acid. (A cloudy precipitate in the ammo-
niacal salt solution does not interfere with complete extraction. It is necessary to
‘keep the volume small in order to exhaust the alkaloid in the least number of extrac-
tions.) Immediately extract, at least six times, with chloroform containing 10%
alcohol, using 30, 20, 20, 10, 10, 5 cc., or until the alkaloid is completely removed.
(Test for the totalremoval of the alkaloid after the sixth extraction by adding 10 ce. of
chloroform-alcohol solvent. Extract and evaporate ina separate beaker. Dissolve the
residue in a few drops of neutral alcohol and add a dropof methylred. Dilute with 20cc.
of water, carbonate free. A yellow color indicates incomplete extraction. ‘Titrate as
above and add value to total.) Combine the chloroform-alcohol extractions in a second
separatory funnel into the stem of which is inserted a pledget of cotton wet with chloro-
form. Wash the combined extractions with 1 cc. of water. When clear, filter into a
small beaker. Extract the wash water twice with small portions of chloroform-alcohol
solvent. Evaporate on a water bath, using an electric fan to prevent decrepitation of
the residue. Remove immediately when dry. Dissolve the residue with 2-3 cc. of
neutral alcohol (water bath). Add 2-3 drops of methyl red indicator, then add from a
buret 5-10 cc. excess of 0.02 N sulfuric acid, taking note of total amount used. Cover
the beaker and heat to dissolve completely the residue adhering to the upper part of
the beaker. Dilute with 50 cc. of cold, previously boiled water. Titrate back with
0.02 N alkali. The water and alkali should be sufficiently free from carbonates to insure
a sharp end point with methyl red. The difference in the number of cc. of 0.02 N sul-
furic acid added and the 0.02 N alkali required represents the amount of alkaloid.
1 ce. of 0.02. N acid = 7.52 mg. morphine hydrochloride + 3H20 (U. S. P.), or
7.59 mg. morphine sulfate + 5H2O (U.S. P.)
152 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
ALTERNATE METHOD FOR TITRATION OF ALKALOID.
If a sharp end point is not obtained with 0.02 N alkali and methyl red, the titration
may be conducted as follows:
To the alkaloidal residue add 2-3 cc. of neutral alcohol, cover the beaker with a watch
glass and heat on a steam bath until the residue adhering to the upper part of the beaker
is completely dissolved. Add 2 drops of methyl red indicator and without dilution
with water titrate carefully with 0.02 N sulfuric acid to a faint pink, avoiding an excess.
Cover the beaker and digest on a steam bath until particles are completely dissolved.
If more than 2 cc. of alcohol were added, evaporate the excess. Cool and dilute with
50 cc. of boiled water. (The solution should now be yellow.) Finish the titration with
0.02 N acid until a faint red.
COMMENT.
The method has been found to be rapid (1 hour), the alkaline salt solution facilitating
the rejection of the alkaloid, and to yield accurate results. Further, provision is made
for the separation of alkaloids, other than morphine.
TABLE 1.
Typical results of analysis of morphine in commercial tablets.
PRODUCT AMOUNT AMOUNT SHORTAGE SHORTAGE
DECLARED FOUND PER TABLET
grain mg. mg. per cent
Morphine sulfate hypodermic tablet 1 15.62 0.58 3.57
Morphine sulfate tablet triturate n 15.56 0.64 3.95
15.50 0.70 4.31
Morphine sulfate compressed tablet re 13.56 2.64 16.29
13.79 2.41 14.88
Morphine sulfate tablet triturate 3 18.33 2.13* 13.14*
18.46 2.26* 13.95*
Morphine sulfate tablet triturate y 13.26 2.94 18.14
Morphine sulfate hypodermic tablet 2 15.05 1.15 7.09
15.00 1.20 7.40
* Excess.
A morphine alkaloid (U.S. P.) was titrated direct to ascertain its purity which was
99.26 per cent. Three 100 mg. samples were prepared from the control and the follow-
ing amounts were recovered: 98.94; 98.94; 98.85 mg., respectively. The last-mentioned
analysis was made by H. O. Moraw.
CODEINE.
PREPARATION OF SAMPLE.
Proceed as directed under morphine, page 151.
DETERMINATION.
Dissolve the sample in a separatory funnel in the minimum amount of water (5 cc.)
acidified with 2 drops of hydrochloric acid. (It is necessary to keep the volume small
in order to exhaust the alkaloid with the least number of extractions.) Add solid sodium
bicarbonate until slightly alkaline to litmus paper, extract five times with chloroform,
1921| | GLYCART: REPORT ON MORPHINE, CODEINE AND HEROINE 153
using about 30 cc. each time. (If morphine is present, reserve the alkaline solution for
later use and proceed as directed below.)
Combine the chloroform extractions in a second separatory funnel into the stem of
which is inserted a pledget of cotton wet with chloroform. Wash the combined extrac-
tions with 1 cc. of water containing 1 drop of ammonia, then proceed as directed under
morphine, page 151, beginning with “Evaporate on a water bath”.
1 ce. of 0.02 N sulfuric acid =7.87 mg. of codeine sulfate+5 H.O or 8.67 mg. of codeine
phosphate+2 H:0 (U.S. P.).
SEPARATION OF MORPHINE.
Morphine and its derivatives are not dispensed together in the same tablet.
- Codeine, which is administered in comparatively large doses, may contain small
amounts of morphine as an impurity.
The separation is made as follows:
After complete extraction of codeine with chloroform, carefully neutralize the alka-
line solution in the separatory funnel by adding concentrated hydrochloric acid slowly,
drop by drop, then 10 drops in excess. Neutralize with ammonia, finally add 4 drops
in excess. Add 5 cc. of alcohol. Extract with chloroform containing 10% alcohol.
(See morphine.)
COMMENT.
Test for complete extraction of the alkaloid by evaporating a sixth extraction in a
separate beaker. Dissolve the residue in a few drops of neutral alcohol. Add 1 drop
of methyl red. Dilute with 20 cc. of water (carbonate free). A yellow color indi-
cates incomplete extraction. Titrate as above and add value to total.
QUALITATIVE TESTS FOR CODEINE AND MORPHINE.
REAGENTS CODEINE MORPHINE
Concentrated nitric acid Yellow Red
Boiling ether Soluble Insoluble
Solution of fixed alkali Insoluble Soluble
1 drop of ferric chloride solution in dilute potas- Gradually Blue
sium ferricyanide solution turning
green
Microchemical test:
Add 1 drop of 0.1 N iodine to alkaloid, dis- Characteristic
solved in 1 drop of 0.1 N hydrochloric crystals, under
acid on slide low power lens
TABLE 2.
Typical results of analysis of codeine in commercial tablets.
SHORTAGE
PRODUCT DECLARED FOUND PER TABLET SHORTAGE
gram mg. mg. per cent
Codeine sulfate tablet triturates 4 30.85 1.55 4.78
31.16 1.24 3.83
Codeine sulfate tablet triturates 7 14.95 1.25 7.71
Codeine sulfate hypodermic tab- 3 15.06 1.14 7.04
lets 15.03 1.17 7.22
i 16.37 Ose 1.05*
Codeine phosphate hypodermic 4 16.10 0.10* 0.61*
tablets
*Excess.
154 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
HEROINE (DIACETYLMORPHINE).
PREPARATION OF SAMPLE.
Proceed as directed under morphine, page 151, through sentence reading: ‘‘Record the
number of tablets used for the sample’’.
DETERMINATION.
Dissolve the sample in a separatory funnel in 5 cc. of water, containing 1 drop of
acetic acid. Add 1 cc. of ammonia. Extract five times with 25 cc. portions of chloro-
form. Combine the chloroform extractions in a second separatory funnel, into the
stem of which is inserted a pledget of cotton wet with chloroform. Wash the com-
bined extractions with 1 cc. of water. Then proceed as directed under morphine,
page 151, beginning with “‘Evaporate on a water bath’’.
1cc. of 0.02 N sulfuric acid = 8.48 mg. diacetylmorphine hydrochloride+ H,0 (U.S. P.).
COMMENT.
Mineral acids and solutions containing fixed alkali, readily decompose diacetyl-
morphine to morphine and acetic acid. The above method precludes the possibility
of decomposition in the process of analysis.
SEPARATION OF MORPHINE,
Diacetylmorphine may decompose with age, turning tablets to varying shades of
gray. For purposes of estimation of decomposition, the morphine is extracted by treat-
ing the ammoniacal solution remaining in the separatory funnel with chloroform con-
taining 10% alcohol. (See morphine.)
Qualitative test—lHeat the diacetylmorphine residue with concentrated sulfuric acid
and a small quantity of alcohol. Ethyl acetate is formed, which is recognized by its odor.
Microchemical test!.—Crystals with platinic chloride. Transfer a fragment of the
alkaloid to a perfectly clean glass slide and drop upon it, from a buret, 1 drop of 0.1N
hydrochloric acid. When completely dissolved, add a drop of 10% platinic
chloride solution and, without stirring or otherwise disturbing the mixture, examine
under low power of microscope. The precipitate as first formed is amorphous, but
within a minute or so, in the case of pure heroine (10-15 minutes in the case of mix-
tures), clusters of needles form around a nucleus. In a short time the needles begin to
fly off and continue until the whole cluster is disintegrated. This test is infallible for
this alkaloid.
TABLE 3.
Typical results of analysis of (diacelylmorphine) heroine in hypodermic tablets.
PRODUCT DECLARED FOUND aes ea SHORTAGE
grain mg. mg. per cenl
Diacetylmorphine hydrochloride bs 5.40 0.00 0.00
Diacetylmorphine hydrochloride ib 5.20 0.20 3.70
Diacetylmorphine hydrochloride 1's §.12 0.28 5.18
5.19 0.21 3.90
Diacetylmorphine hydrochloride ts 4.45 0.95 17.60
4.70 0.70 13.00
1 J. Ind. Eng. Chem., 1912, 4: 508.
1921) VIEHOEVER: REPORT ON MEDICINAL PLANTS 155
RECOMMENDATION.
It is recommended that the methods herein submitted for the assay of
morphine, codeine and heroine be studied during the coming year with
a view to their final adoption by the association.
REPORT ON MEDICINAL PLANTS.
By Arno VieHOEVER (Bureau of Chemistry, Washington, D. C.), As-
; sociate Referee.
The report is divided into four parts:
I. Detection of molds in drugs, foods and spices, by means of the
chitin test.
II. Identification and differentiation of plants and plant products
by means of the pollen grains.
III. Value of weights of unit volumes or the specific weight of crude
drugs and spices.
IV. Important adulterants and substitutes of crude drugs and spices.
PART I.
The importance of the detection of the presence of mold in drugs,
foods and spices is very evident. Where the growth of mold is very con-
spicuous, covering to a greater or less degree the particular product,
analytical proof is usually superfluous. A cultural and microscopic
study of the mold in such instances can readily be made. Where, how-
ever, the material is not conspicuously infested on the outside, or where
it is processed by powdering or otherwise, thus materially changing the
appearance of the product, the problem of detecting and identifying
the mold becomes far more difficult of solution. Cases are not rare in
plant or animal pathology where it is desired to establish the extent
of infestation or mold growth in the tissues. Especially serious is the
problem where molds, poisonous eyen in very small amounts, are sus-
pected in food products, such as ergot in flour, or ergotized spices, such
as ergotized caraway and cumin.
Mainly to facilitate the task of the analyst, in stich cases, a method is
described, based on the presence of a specific chemical substance, chitin,
in the cell wall of molds and other fungi cells. This substance, by a
special treatment, is transformed in such a manner that it can be specifi-
cally stained. The subject has been discussed by the writer at some
length!.
The following method has been suggested for the treatment and stain-
ing of the mold-infested material:
1 J. Am. Pharm. Assoc., 1917, 6: 518.
156 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
METHOD.
Heat the material containing the mold almost to boiling with 40-50% potassium
hydroxide or sodium hydroxide for 40-60 minutes. The heating may be done con-
veniently on an electric plate, in a flask, the opening of which is covered with a funnel.
After centrifugalizing, if necessary, decant the excess of potassium hydroxide. If
practicable, press out the material with a glass rod to remove as much as possible
of the potassium hydroxide. Then wash with alcohol or glycerol (about 50%) depend-
ing on the nature of the product.
STAINING OF CHITOSAN.
After removing the last traces of potassium hydroxide with dilute alcohol or glycerol
(about 25%), and possibly neutralizing at the end with 1% sulfuric acid, treat the
material with a solution of iodine potassium iodide (2 parts of iodine, 1 of potassium
iodide, and 200 cc. of water). Then replace the excess of iodine with dilute sulfuric
acid, preferably 1%. In the presence of chitosan a distinct red to violet color is detected.
SPECIAL REMARKS.
If the treatment with potassium hydroxide is not unduly extended, the plant tissue
is not very much destroyed and the stain brings out the mold mycelium very distinctly.
In case the color should not be distinct or even be covered with another color in the
hyphae, the untreated material may, according to van Wisselingh' and Wester?, first
be heated with glycerol to 300°C. and then treated with potassium hydroxide.
If the material contains large amounts of starch, which may give a color somewhat
similar to that of chitosan, the starch can be hydrolyzed with freshly prepared diastase
from malt or with taka-diastase or can be differentiated from the mold with the polari-
zation microscope through its ability to refract the light.
Since alkali carbonates do not seem to effect the transformation of the cell substance,
chitin, as well as hydroxides, it is essential that the solution of alkali hydroxides used
should not contain considerable amounts of carbonates. After treatment with potas-
sium hydroxide it is often advisable to make the test with part of the material trans-
ferred to a watch glass or object slide. It is important that the free potassium hydrox-
ide be removed completely since otherwise the iodine solution will be discolored and
prevent the stain from developing.
The material must be actually stained with iodine solution before replacing the
iodine with dilute sulfuric acid. For purposes of preservation, the preparation is best
kept in dilute glycerol (1 to 1). The stain becomes gradually weaker and disappears
after about 24-48 hours.
Copies of the method and a sample of ergotized caraway, as well as
moldy areca nuts, were submitted to a number of collaborators, with
the request that the test be tried. The following replies were received:
E. O. Eaton.—The test appears, on limited application, to be of value. I obtained
positive results on known molds treated as directed, as well as in samples submitted.
G. L. Keenan.—Several fragments of ergot were heated, etc., (according to method).
A distinct violet-red color was obtained.
Miss M. B. Church.—I have tried the chitin test mainly on canned strawberries,
rotten cherries, molded soy beans and occasional crude drugs. Attempts to use it on
1 Jahr. wiss. Bolanik, 1898, 31: 619.
? Studien iiber das Chitin. Inaugural Disserlalion, Bern. (1909).
1921] VIEHOEVER: REPORT ON MEDICINAL PLANTS 157
lumps of moldy flour were not satisfactory, because of the awkwardness natural to hand-
ling starchy stuff with a hydroxide in such technique. We have never been interested
in centrifugalizing minute amounts of material treated with the chitin test and exam-
ining minute quantities of residue for fungal cellulose, because occasional mold or
bacteria is regarded as of no importance for our work. Therefore I can not discuss
the fineness of the method to any extent. I have always been able ultimately to make
the chitin test work. I have been successful in training my eye to recognize to my
positive satisfaction the shade of pinkish purple which means fungal cellulose. I have
never seen any other material staining this particular shade.
C. W. Ballard—I am very much interested in the question of molds in foodstuffs
and have used the method described in your article. I find that the results are good
and certain. In one investigation it was necessary to identify small quantities of mold
in canned pumpkin. You know how closely broken mold filaments resemble broken
cellulose walls. Nevertheless, the method was used. In this instance, the parenchyma
cell walls were stained blue and one had to depend upon structural characters as well
as staining properties. I have also used the method in working with condensed milk
containing mold buttons. In this instance it was necessary to work with dilute solu-
tions and centrifugalize.
E. N. Gathercoal.—I made the test on the two samples that you sent me, and found
{t to work very well, indeed. I also tried it on a sample of moldy bread, but found
that the detection of the mold hyphae was difficult because the starch was not com-
pletely destroyed. The test would appear to be a very satisfactory one for the detection
of fungi in powdered drugs where the fungal threads would be difficult to locate among
the other tissues without this special treatment. However, in material such as bread,
preserved fruits, etc., the usual microscopic mounts would be much quicker, and per-
haps as satisfactory for the detection of the mold threads.
J. F. Clevenger.—Various products in the course of routine work, such as moldy
coffee, moldy oats, and certain spices or drugs infested by mold, were treated according
to the method suggested in the chitin test. The stain could always be obtained,
although it seems necessary to follow the procedure suggested quite carefully, and
advisable to prolong the treatment of boiling, etc., in cases where the mold hyphae are
only partly and indistinctly stained.
PART II.
With regard to the use of pollen grains in the differentiation of drugs
and other plant products, the main thought is to utilize the means of
differentiation readily accessible in nature as in herbariums, and yet
evidently vcry much neglected by botanists and analysts in the identi-
fication of plants and plant products. From a study of the data given
in literature, as well as from the limited data “secured in laboratory
analyses, it is believed that the pollen grain has a specific and constant
structure. It is true, as far as morphological classes are concerned, mainly
flowers and herbs collected in the flowering state will be suitable material
for testing.
In the microscopical examination of honey, pollen grains are used
to ascertain the origin of the honey. It is hoped that the use of pollen
grains can be extended. Many plants of economic or medicinal value
are collected during the flowering period. Most herbarium specimens
are collected during that time, inasmuch as the taxonomists base the
158 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
identification, whenever possible, on floral characteristics. By the use
of the outline and size of the pollen grains and the morphological struc-
ture of the exine, and correlating the results with other means of iden-
tification and differentiation of varieties, genera, and families, very
useful data will be at hand to establish the identity of the product.
Perhaps it may not always be desirable or possible to depend upon this
pollen character alone, but the accessibility of the pollen, the uniformity
in structure, the specific character, and the fact that it is not
subject to decomposition, will speak strongly in favor of its adoption
for taxonomical purposes. It is believed that a most desirable asset to
a collection of drugs and other plant products would be a collection of
pollen grains associated with the individual drug samples, which would,
no doubt, in many instances, make the authenticity of the material un-
questionable.
The following method was tentatively suggested:
METHOD,
Place the material containing floral structures, especially pollen grains, on a micro-
scopical slide, mix with dilute glycerol (1 to 1), or a mixture of equal amounts of chloral
hydrate solution (8 to 5) and glycerol. After covering with a cover glass, examine
under the microscope. The magnification to be used varies with the size of the pollen
grains, but usually a magnification varying from 400-600 will be found satisfactory.
Examine the pollen grains, which are recognized by their characteristic structure, as
to size, outline, and morphological structure of the exine, the outer pollen grain wall.
Also determine the number of openings for the pollen tube. In some instances treat-
ment with concentrated sulfuric acid may be found to give a characteristic reaction,
such as with pollen grains of Mallow (Malva sylvestris L.), which are colored distinctly
red upon the addition of sulfuric acid.
Pollen grains in liquid suspension, such as honey, are readily found in the sediment,
if necessary, after dilution and centrifugalizing of the liquid, or, preferably, after set-
tling in sediment tubes or apparatus.
A number of collaborators were approached with the request to re-
late the extent of their experience, if any, in the use of pollen grains as
a diagnostic means for differentiation of drugs and other plant
products.
C.W. Ballard.—This procedure is satisfactory in working with herbs and aboveground
portions but, in my opinion, is of little use in working with other parts of the plant.
E-.N. Gathercoal.—We have had little experience regarding the use of pollen grains as
a diagnostic means for differentiation of drugs and other plant products. We have
met with pine pollen as a substitute for lycopodium and some years ago we found a
good deal of pollen in a sample of powdered belladonna leaves. We decided that this
was belladonna pollen and that the sample consisted mostly of flowering tops.
Albert Schneider! discusses the value of pollen grains in drug analysis
and appears to be in favor of their use as diagnostic elements.
1 Microanalysis of Powdered Vegetable Drugs. 2nd ed., 1921, 102,
1921] VIEHOEVER: REPORT ON MEDICINAL PLANTS 159
The writer has collected a great number of data from literature and,
with the aid of J. F. Clevenger, has established the characteristic pollen
grain structures of several drugs, such as Onopordon, Convallaria, and
Matricaria (chamomile).
PART III.
The work on the value of weights of unit volumes of crude drugs and
spices, discussed in previous reports!, was continued.
C. J. Zufall submitted a large number of interesting data, which
demonstrated the usefulness of the method. (See Table 1.) Inasmuch,
however, as it was feared that the individual factor of filling the cylinder
with material may vary considerably and cause unsatisfactory results,
the work was continued along a line which appeared to eliminate this
factor of chance. An apparatus devised by Kunz-Krause? in 1919 for
the determination of the apparent or absolute specific weight of sub-
stances was used. It consisted of a flask not unlike a picnometer, the
upper part ending in a narrow tube and fitting with a ground joint into
a glass of suitable size. The volumes in the two flasks used were 62 and
142. Kerosene, made moisture free with anhydrous sodium sulfate,
was used according to the suggestion of Kunz-Krause. A known amount
(about 20 grams) of the vegetable material to be tested in whole or
ground state, was filled into the lower part after about 20 cm. of kero-
sene had been previously introduced into the flask, using the larger one
for the data reported.
The apparatus was put together, using a drop of water to effect a good
joint of the ground faces, and kerosene filled in from a buret to the mark
indicated on the neck of the flask. The difference in volume of kerosene
needed to fill to the mark, representing the amount of liquid displaced
by the added vegetable material, divided by the actual weight of the
drug added, represents the desired result. Where drugs in a whole state
are used this is identical with the apparent specific weight; where the
finely ground material is used, it is identical with the absolute specific
weight.
Data thus obtained are tabulated in Table 2.
1 J. Assoc. Official Agr. ese. 1920, 4: 149; 1921, 4: 409.
2 Ber. pharm. Ges., 1919, 147.
160 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TABLE 1.
Weight per unil volume of some crude drugs.
(Analyst, C. J. Zufall.)
DESCRIPTION WEIGHT
OF DIVIDED BY REMARKS
SAMPLE VOLUME
Anise seed 0.377* Average appearance. Rock fragments, 1%;stems,0.5%.
Anise seed 0.363* Average appearance. Sand, 0.5%; stems and foreign
matter.
Anise seed 0.360* 2% fine sifting of stems and anise seed fragments.
Anise seed 0.376 1% sand.
Anise seed 0.372 Average appearance very clean.
Anise seed 0.380 Average appearance very clean.
Anise seed 0.397 Average appearance very clean.
Anise seed 0.445 N. Y. 79655. Exhausted seeds 65%, much dust.
Anise seed 0.333 Exhausted completely with steam in laboratory.
Anise seed 0.382 conan 10% seeds exhausted in laboratory. Grade
, 90%.
Anise seed 0.387 Contains 20% seeds exhausted in laboratory. Grade
A, 80%.
Anise seed 0.370 Contains 50% seeds exhausted in laboratory. Grade
A, 50%.
Anise seed 0.341 Partially exhausted in laboratory.
Anise seed 0.315* Partially exhausted in laboratory.
Caraway seed 0.478 Dutch. Very clean.
Caraway seed 0.477 Dutch. Very clean.
Caraway seed 0.496 Dutch. Very clean.
Caraway seed 0.457 Dutch. Very clean.
Caraway seed 0.466 Dutch. Very clean.
Caraway seed 0.470 Dutch. Very clean.
Caraway seed 0.498 Dutch. Very clean.
Caraway seed 0.469 Dutch. Very clean.
Caraway seed 0.499 Dutch. Very clean.
Caraway seed 0.503 Dutch. Very clean.
Caraway seed 0.504 African. Pedicels, 1%, and stems, 1%.
Caraway seed 0.501 African. Very clean.
Coriander 0.310 No stems, soil or foreign matter. Normal appearance.
Coriander 0.311 No stems, soil or foreign matter. Normal appearance.
Coriander 0.326 No stems, soil or foreign matter. Normal appearance.
Coriander 0.306 No stems. Soil particles, 1%, same size as coriander.
Coriander 0.304 No stems. Soil, 1%. Shaking produced no change
in volume.
Coriander 0.294 Soil, 0.5%.
Celery seed 0.503* No dust. Sand, 0.5%.
Celery seed 0.476 Sand, 1%. Very little dust. :
Cubebs 0.306 Average appearance. Stems, 5%. No other foreign
matter. Many small fruits.
Cubebs 0.262* Average appearance. Stems, 4%.
Cubebs 0.190* Fruits very small. Stems, 50% and { to 1 inch in length.
Cumin seed 0.305* Average appearance. Small rocks, 0.5%.
Cumin seed 0.324* Average appearance. Small rocks, 1.5%.
Cumin seed 0.364* Average appearance. Very clean.
Cumin seed 0.350* Average appearance. Very clean.
Cumin seed 0.360 Average appearance. Very clean.
Cumin seed 0.373 Average appearance. Few small pebbles.
Fennel seed 0.325* Average appearance. Less than 1% sand.
Fennel seed 0.276* Average appearance. Large German. Very clean.
Fennel seed 0.310 Average appearance. Large German. Very clean.
Fennel seed 0.296 Average appearance. Large German. Very clean.
Fennel seed 0.301 Average appearance. Large German. Very clean.
Fennel seed 0.301 Average appearance. Large German. Very clean.
1921] VIEHOEVER: REPORT ON MEDICINAL PLANTS 161
Taste 1.—Continued.
DESCRIPTION WEIGHT
OF DIVIDED BY REMARKS
SAMPLE VOLU ME
Fennel seed 0.694 Small French bitter fennel. Old, dark and moldy.
Fennel seed 0.389 Medium size. German. Very clean.
Fennel seed 0.3877 Medium size. German. Very clean.
Fenugreek seed 0.723 Soil, 0.5%. No other foreign matter.
Juniper berries 0.430 Less than 1% brown fruits.
Juniper berries 0.383 | Shrivelled fruits, 1%.
Lycopodium 0.378 No starch or foreign matter. Very dry. Ash, 1%.
Lycopodium 0.363 No starch or foreign matter. Very dry. Ash, 1.2%.
Lycopodium 0.408 Nostarch. Foreign vegetable matter, 0.3%. Ash, 1.77%.
Lycopodium 0.340* No starch or foreign vegetable matter. Ash, 11.6%.
Lycopodium 0.400* Starch, 20%. No foreign vegetable matter. Ash, 8%.
Marjoram 0.108* Average. No Coriaria. Very clean.
Marjoram 0.109* Average. No Coriaria. Very clean.
Marjoram 0.096* Average. No Coriaria. Very clean.
Marjoram 0.125 Average. No Coriaria. Very clean.
Marjoram 0.106* Average. No Coriaria. Very clean.
Marjoram 0.136 Average. No Coriaria. Very clean.
Mustard seed 0.710 Average. Very clean. English yellow.
Mustard seed 0.735 Average. Very clean. English yellow.
Mustard seed 0.737 Average. Very clean. English yellow.
Mustard seed 0.755 Average. Very clean. English yellow.
Mustard seed 0.752 Average. Very clean. English yellow.
Mustard seed 0.744 Average. Very clean. English yellow.
Mustard seed 0.717 Average. Very clean. English yellow.
Mustard seed 0.707 Average. Very clean. English yellow.
Mustard seed 0.712 Average. Very clean. English yellow.
Mustard seed 0.712 Average. Very clean. English yellow.
Mustard seed 0.731 Average. Very clean. English yellow.
Mustard seed 0.717 Average. Very clean. English yellow.
Mustard seed 0.686 Average. Very clean. English yellow.
Mustard seed 0.688 Average. Veryclean. English yellow.
Mustard seed 0.719 Average. Very clean. English yellow.
Mustard seed 0.723 Average. Very clean. English yellow.
Mustard seed 0.719 Average. Very clean. English yellow.
Mustard seed 0.713 Average. Very clean. English yellow.
Mustard seed 0.751 Average. Very clean. English yellow.
Mustard seed 0.719 Slightly moldy. Foreign seeds, 4%. English yellow.
Mustard seed 0.751 Slightly moldy. Foreign seeds, 3%. English yellow.
Mustard seed 0.733 Danish yellow. Very clean.
Mustard seed 0.678 Chinese yellow. Very clean.
Mustard seed 0.687 Danish brown. Very clean.
Mustard seed 0.682 Danish brown. Very clean.
Mustard seed 0.695 Danish brown. Very clean.
Poppy seed 0.636 Blue. Very clean.
Thyme 0.236 Very clean.
Thyme 0.199 Very clean.
* Drug not shaken down. All other results from shaking sample down as far as it would go. Nearly all
samples consisted of 1000 cc.
162 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TABLE 2.
Specific gravity and other data* for crude drugs and spices.
ASH
PECCERIC |e ena | a
PRODUCT CONDITION GRAVITY PER E REMARKS
500 ce. | Total Acid-
insoluble
grams | percent| per cent
Pepper, Tellichery Whole 1.11 | 276 noes cratic Good grade
Pepper, Tellichery Ground No. 60) 1.33 a5 4.2 0.3 Good grade
Pepper, Acheen Whole T0087 202) {Il 3.5 .... | Poor quality
Pepper, Acheen Ground No. 60} 1.29 ashe 5.6 1.4 Poor quality
Veratrum viride Fine powder 1.53 19.0 15.2
Veratrum album Fine powder 1.43 4.9 2.0
Veratrum album Coarse powder} 1.33 6.2 3.1 | Roots only
Black mustard
(Brassica nigra) Whole seed 1.16
Rape, (Brassica napus)| Whole seed 1.08
Mustard, (Brassica
besseriana) Whole seed 1.17
Chinese colza (Brassi-
ca campestris var.
Chinoleifera Vie-
hoever) Whole seed Tigi
White mustard (Sin-
apis alba) Whole seed 1-23;
* Data secured by J. F. Clevenger and Ruth G. Capen.
The difference in weight observed suggests the usefulness of the method.
The presence of ash in the sample of Veratrum is clearly indicated by
the higher specific weight. Further work must, of course, be done.
PART IV.
Samples of sage (Salvia officinalis) put up in small packages, proved
to be Greek sage (Salvia triloba L.). Powdered capsicum proved to be
a species other than frutescens, official in the U. S. Pharmacopeia. A
sample labeled ‘‘ Allspice’’ was identified as Vitex agnus-castus L.
Among the imported drugs found to be substituted should be men-
tioned cubebs, containing close to 75 per cent of the fruit of another
Piper species, Piper ribesioides' Valerian U. S. P. substituted by a
Mexican species, as well as by an Ecuadorian species; Convallaria
flowers (Convallaria majalis) for Matricaria; China rubra for cascara.
A very skilful fake saffron was offered for entry. It was proved to
consist entirely of flowers resembling the common thistle and represent-
ing the species Onopordon siblhorpianum Boiss and Heldr. This was
artificially colored with a red dye, Ponceau 3 R, and a yellow dye, tar-
trazine. It was weighted with a salt mixture of potassium nitrate, borax
and also glycerol and evidently flavored with saffron oil.
1921] HANSON: METHOD FOR THE EXAMINATION OF PROCAINE 163
RECOMMENDATIONS.
It is recommended—
(1) That the method for the detection of molds in drugs, foods and
spices, by means of the chitin test, be adopted as a tentative method.
(2) That the method for the use of pollen grains as a means of identi-
fication and differentiation of plants and plant products be further
studied.
(3) That further work be done on the value of weights of unit volumes
~ or the specific weight of crude drugs and spices.
(4) That further information be collected concerning adulterants and
substitutes of crude drugs and spices.
No report on enzymes was made by the associate referee.
METHOD FOR THE EXAMINATION OF PROCAINE
(NOVOCAINE)!
By Atrrep W. Hanson (U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, IIl.).
In the examination of procaine it is well recognized that the base may
be extracted from an ammoniacal solution with ether or chloroform and
determined by titration in the usual manner employed for alkaloids.
In studying the chemical properties of procaine, it was found that it
can be titrated directly with potassium bromide-bromate reagent after
first hydrolyzing. Details of a method based upon this principle have
been devised and the results of the examination of samples of procaine
appear to be quite satisfactory.
In examination of this drug it seems advisable that qualitative tests
be made for the purpose of identification.
REAGENTS,
(A) Mercuric potassium iodide (Mayer's reagent).—Dissolve 1.3 grams of mercuric
chloride in 60 ce. of water, add 5 grams of potassium iodide dissolved in 10 ce. of water
and make to 100 ce. <
(b) Potassium permanganate solution.—Dissolve 5 grams of potassium perman-
ganate in water, and make to 100 ce.
PHYSICAL AND CHEMICAL TESTS.
(1) Procaine melts at 153-155°C.
(2) Dissolve @.1 gram of procaine in about 10 cc. of water. When this solution is
treated with 2 cc. of the potassium permanganate solution, reduction occurs with
evolution of gas having the odor of acetaldehyde (distinction from cocaine, which does
not readily reduce potassium pernienganate).
1 Presented by G. W. Hoover.
164 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V. No. 2
(3) Dissolve about 5 mg. of the sample in 5 cc. of water, adding a few drops of mer-
curic potassium iodide (Mayer’s reagent). In the case of procaine, a white precipitate
is formed which dissolves if a few cc. of dilute sulfuric acid are added. (The precipi-
tates with mercuric potassium iodide (Mayer’s reagent) formed with stovaine and
cocaine are not readily soluble in dilute sulfuric acid.)
(4) Dissolve about 0.1 gram of procaine in 5 cc. of water. Add 2 drops of dilute
hydrochloric acid, 2 drops of 10% sodium nitrite solution, and mix with a solution of
0.2 gram of betanaphthol in 10 cc. of 10% sodium hydroxide solution. A scarlet red
precipitate is formed.
(5) To a solution of about 0.1 gram of procaine in 5 ce. of water, add 3 drops of dilute
sulfuric acid, and mix with 5 drops of 0.1 N potassium permanganate. The violet
color of the latter disappears immediately (distinction from cocaine).
(6) Dissolve about 0.1 gram of procaine in 1 ce. of sulfuric acid. The solution is
colorless (organic impurities).
REAGENTS.
(a) 0.1N sodium hydroxide (for hydrolyzing upon steam bath).
(b) 0.1N sodium thiosulfate.
(C) Potassium iodide solution.—Dissolve 20 grams of potassium iodide in water and
make to 100 ce.
(d) Potassium bromide-bromate solution—Dissolve 3 grams of potassium bromate
and 15 grams of potassium bromide in water. Make to 1 liter (this should be standard-
ized against 0.1 N sodium thiosulfate).
(e) Starch indicator—Mix about 0.5 gram of finely powdered starch with cold
water to a thin paste, pour into about 100 cc. of boiling water, stirring constantly, and
discontinue heating immediately after the paste is added.
DETERMINATION.
Dissolve 0.1 gram of the sample in 5 cc. of water in a 50 cc. beaker. Add 25 ce. of
0.1.N sodium hydroxide and heat upon a steam bath for 25 minutes. Cool, transfer
the solution to a 500 cc. Erlenmeyer flask, having a tightly fitting ground glass stopper.
Add 50 cc. of accurately measured standardized potassium bromide-bromate solution.
Dilute with water to 250 cc. Add 10 cc. of hydrochloric acid, stopper the flask immedi-
ately to avoid loss of bromine. Shake the flask occasionally and allow to stand for 30
minutes at room temperature, keeping the flask tightly stoppered (it is necessary that
a large excess of bromine be present, as shown by a bright yellow color). Add quickly
10 cc. of potassium iodide solution, stopper and shake the flask. Allow to stand for 15
minutes, shaking occasionally. Titrate the excess of iodine with 0.1.N sodium thio-
sulfate solution, using starch indicator. Titrate to disappearance of the blue color
(a blue color develops later and should be disregarded). Calculate the amount of
0.1N bromine combined with procaine. One cc. of 0.1N bromide-bromate solution
is equivalent to 0.00455 gram of procaine.
RESULTS OF ANALYSIS.
Titration afler hydrolyzing with 25 cc. of 0.1 N sodium hydroxide on steam bath.
PROCAINE 0.1 N BromIDE-BROMATE PROCAINE FOUND BY
BECUINED CALCULATION
gram cc. gram
0.02 4.7 0.021
0.5 10.8 0.049
0.10 21.7 0.099
1921) HANSON: METHOD FOR THE EXAMINATION OF PROCAINE 165
COLLABORATIVE WORK.
Titration of procaine after hydrolyzing on steam bath.
0.1 N
ANALYST PROCAINE Saoaine ences PROCAINE FOUND
REQUIRED BY CALCULATION
gram cc. gram
L. Jones, U. S. Food 0.05 10.8 0.0491
and Drug Inspec- 0.10 21.8 0.0999
tion Station, Chi- 0.15 32.6 0.1483
cago, Ill. 0.20 43.4 0.1975
H. O. Moraw, U. S. 0.05 10.6 0.0484
Food and Drug - 0.10 21.6 0.0982
Inspection Station, 0.15 32.2 0.1465
Chicago, Il. 0.20 43.6 | 0.1984
Titration of procaine in hypodermic tablets after hydrolyzing on steam bath.
0.1N
ANALYST PROCAINE DECLARED BROMIDE-BROMATE EROCAINES/ FOUND
REQUIRED BY CALCULATION
gram cc. gram
A. W. Hanson 0.02* (1 tablet ) 4.7 0.0214
0.04* (2 tablets) 9.3 0.0423
0.06* (3 tablets) 14.0 0.0637
L. Jones 0.05* (23 tablets) 11.6 0.0528
0.10* (5 tablets) 23.9 0.1087
A. W. Hanson 0.057 (1 tablet ) 10.2 0.0464
0.107 (2 tablets) 21.1 0.0960
0.157 (3 tablets) 32.0 0.1456
L. Jones 0.057 (1 tablet ) 10.8 0.0491
0.107 (2 tablets) 21.45 0.0976
* Procaine Hypodermic Tablets. Label: Each tablet contains 0.02 gram (4 grain) Procaine, 0.00004
gram Adrenalin. 4 grain=0.0216 gram.
t Procaine Hypodermic Tablets. STabal: Each tablet contains 0.05 gram (3 grain) Procaine. j grain
=0.0486 gram.
COMMENTS.
Procaine is a para-amino-benzoic acid derivative. By heating pro-
caine with 0.1 N sodium hydroxide, the compound is decomposed, libera-
ting the para-amino benzoate which can be titrated by bromination.
In titrating the procaine, 3 molecules (6 atoms) of bromine are required,
as in the cases of phenol and salicylic acid.
In case tablets are to be analyzed, it may be advisable to make up a
definite quantity to a known volume, using slightly acidulated water
and a volumetric flask. Any water-insoluble material can then be filtered
off and aliquots taken for the titration. It is possible to obtain a repre-
sentative sample of a large number of tablets in this manner. The pres-
ence of salt, which is usually used in the preparation of procaine tablets,
does not interfere with the titration. A control should be run if other
substances are present.
166 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
RECOMMENDATION.
It is recommended that the method submitted herewith be studied
during the coming year with a view to its adoption by the association
if found satisfactory.
STUDY OF THE DISTILLATION METHOD FOR THE ESTI-
MATION OF SANTALOL IN SANTAL OIL.
By C. W. Harrison (U.S. Food and Drug Inspection Station, Park
Avenue Building, Baltimore, Md.).
The following methods, with notes and explanations, were sent to
the collaborators:
INSTRUCTIONS TO COLLABORATORS.
U. S. PHARMACOPEIA METHOD.
Acetylate the oil as directed in the U. S. Pharmacopoeia! and into a 100 cc. Erlen-
meyer flask weigh accurately about 5 cc. of the dry, filtered, acetylated oil. Pipet
50 ce. of alcoholic potash (approximately 0.5N) into the Erlenmeyer flask, measuring
at the same time with the same pipet drained a similar length of time another 50 cc.
portion of the alcoholic potash to carry through as a blank. Insert into the neck of
the flasks containing the sample and blank, small short-necked funnels, place on a
steam bath and heat until the oil is completely saponified; this will require about 1
hour. When saponification is complete, titrate the sample and blank with 0.5N sul-
furic acid and phenolphthalein.
Ce. of 0.5N acid required to neutralize blank minus cc. to neutralize sample = cc. of
0.5N potassium hydroxide required to saponify the weight of oil taken. This figure is
designated as ‘‘A”’ in the following formulae:
AX 11.11
as taantaloltSsPemnethed!
Weishtotasctslated OiaGAnOMet)s a. ye a a
Also calculate the saponification number of acetylated oil as follows:
A X 28.06
Weight of acetylated oil.
HARRISON DISTILLATION METHOD.
Render the flask containing the residue, after determination of the santalol by the
U.S. P. method, very faintly alkaline with 1-2 drops of alcoholic potash, place on the
steam bath and evaporate to a volume of about 10 cc. (this is accomplished by using
suction to remove the vapors).
Carefully transfer the contents of the flask to a volatile acid apparatus of the modi-
fied Hortvet type. Make the transfer by pouring as much of the contents of the flask
as possible through a funnel into the apparatus, then rinse the flask and funnel with
successive small portions of dilute sulfuric acid (approximately 10 per cent by weight)
until the contents of the apparatus are distinctly acid to methyl orange, 1-2 drops of
which have been added to the apparatus. This should not require more than 15-20 ce.
of acid. It is necessary to keep this volume small or it will delay unnecessarily the
time of distillation.
1U. S. Pharmacopeia, IX, 1916, 296.
1921] HARRISON: STUDY OF THE ESTIMATION OF SANTALOL 167
Then start the distillation. Most of the volatile acids will pass over in the first 150
cc. of distillate but it will require about 350 ce. of distillate to carry over the last traces
of volatile acids.
Titrate the distillate with 0.5 N alkali and phenolphthalein and calculate the results
as follows:
ce. 0.5 N alkali X 11.11
Weight of acetylated oil — (cc. of 0.5 N alkali X 0.021)
=per cent santalol, by
distillation method.
NOTES AND EXPLANATIONS OF THE METHODS.
The present U.S. P. assay of oil of santal is not applicable if the oil has been adul-
terated with a saponifiable oil and the distillation method is designed to show this class
of adulteration.
The method is comparatively simple; the only standardized solutions required are
0.5 N sulfuric acid and 0.5 N sodium hydroxide. The other solutions used need be only
approximate strength, 0.5 N alcoholic potash and 10 per cent by weight sulfuric acid.
The volatile acid apparatus is a modified form of the Hortvet apparatus which has
been used in the Bureau of Chemistry for some years and was made by the glassblower.
It consists of an elongated bulb, about 6} inches long and 13 inches in diameter,
sealed at the lower end, the upper end drawn into a tube about 2} inches long with an
internal diameter about ;5, inch. This tube passes through a No. 9 rubber stopper
and the upper end connects by a goose neck and rubber tube to a condenser. The No.
9 rubber stopper fits into a 2-liter Erlenmeyer flask which serves as a steam reservoir
and into which the bulb, which contains the liquid to be distilled, fits.
From the side of the bulb, less than half its length from the top, a glass tube passes
through the side wall and extends almost to the bottom of the bulb. This allows the
steam to pass from the reservoir and bubble through the liquid in the bulb, thus carry-
ing over the volatile acids. A small glass tube with a stop cock also passes through
the rubber stopper into the steam reservoir and serves as a vent. This is left open
until the distillation is well under way. A few glass beads are placed in the Erlenmeyer
flask to give a uniform boiling.
A convenient way of drying the acetylated oil is to place it in a small cylinder, filled
nearly to the surface of the liquid with anhydrous calcium chloride (4 mesh), and
allow it to stand overnight, then filter.
Description of the four samples and their constants, as determined
by the writer, are as follows:
Sample No. 1.—Oil of Santal, East India U.S. P. Fritzsche Bros., New York, N.Y.
Specific gravity Be"... 2... eee cece eee rhe ens teins 0.973
Refractivesmdex, at) 257 Cis jejesisie/oe s cvayerate orale acer nels te are 1.5045
Opticalixotation/100/ mm: ati25°Gs. 3... boos ecele. ne <6 —18.4
Solubility 5 volumes 70% alcohol. Complete except slight
turbidity.
Sample No. 2.—Santal Oil, Oleum Santali, U.S. P. 1X, East Indian. ‘“‘Distilled from
genuine imported East Indian Sandalwood logs by Sharp & Dohme, Baltimore, Md.”
Specilicrgravityge= entreaties « Gia acres oh hee 0.972
Refractive index: at 25 mews aceite ete eca.ssvorsieeisiziis aisles) eo esie 1.5039
Opticalirotationul OObnmig2 52a sas. oe ss)siceceyeitien waseee ee —18.2
Solubility 5 volumes 70% alcohol. ...................Complete
168 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol.
SantallioiMNowhs.4.e6h saenuie 75 per cent.
Sample No. 3.—Mixture Palmmnut.ol 2 jacccatscoecee 19 per cent.
@ubebroilr ia. ss ene cele neroe 6 per cent.
Optical rotation 100 mm. tube at 25°C. .............. —15.0
Solubility 5 volumes 70% alcohol............... Not complete
, SantallioulNo? 2506 ya sce cia ete 80 per cent.
Sample No. 4.—Mixture Cocoanut olles5..¢ eee ee Lonpericents
Copaibatoil rerr4.0.222 anise 6 5 per cent.
Optical rotation 100 mm. tube at 25°C.............. —15.0
Solubility 5 volumes 70% alcohol.............. Not complete
V, No. 2
The results of the collaborators on these four samples are given in
the following table:
Tas.e 1.
Comparative results oblained by two methods.
SAPONIFICATION Bee
SAMPLE NUMBER AND ANALYST NUMBER OF SANTALOL HARRISON
& ACETYLATED OIL U. 8. P. METHOD DISTILLATION
METHOD
Sample No. 1: per cent per cent
E. K. Nelson, Bureau of Chemistry, 196.7 91.4 86.1
Washington, D. C.
C. W. Harrison. 197.6 92.6 85.3
siesta 91.0 Be a
ays assets 93.0
E. O. Eaton, U.S. Food and Drug In- 196.8 91.4 92.2
spection Station, San Francisco, Calif. 199.0 92.7 wade
C. K. Glycart, U.S. Food and Drug In- 204.7 93.1 85.5
spection Station, Chicago, Ill. 201.6 91.8 87.2
A. W. Hanson, U.S. Food and Drug In- 199.3 92.8 88.4
spection Station, Chicago, Ill. 200.0 93.1 90.5
Maximum) variation)... acess 204.7 93.1 92.2*
Minimumiyariationcs. ese ee scien: 196.7 91.0 85.3
* Eaton did not use the distillation apparatus described in the method
1921 HARRISON: STUDY OF THE ESTIMATION OF SANTALOL 169
TABLE 1.—Continued.
SANTALOL
SAPONIFICATION SANTALOL HARRIGON
SAMPLE NUMBER AND ANALYST NUMBER OF U. Ss. P. DISTILLATION
‘ ACETYLATED OIL METHOD METHOD
Sample No. 2: per cent per cent
E. K. Nelson 194.3 90.0 86.1
C. W. Harrison 192.0 88.9 84.1
E. O. Eaton 197.6 92.1 84.2
200.3 93.1 84.2
C. K. Glycart 205.3 96.0 82.9
: 200.0 92.4 87.3
A. W. Hanson 199.3 92.9 89.4
Maximum variation ................... 205.3 _ 96.0 89.4
Minimum variation ................... 192.0 88.9 82.9
Sample No. 3:
E. K. Nelson 199.4 92.8 71.4
C. W. Harrison 196.5 91.3 69.9
197.0 91.4 70.3
E. O. Eaton 202.4 94.5 75.8
197.5 91.8 stators
C. K. Glycart 205.0 96.5 73.3
A. W. Hanson 197.7 91.8 73.6
Maximum variation ........5..5.....20. 205.0 96.5 75.8
Mmimum Variations: a.s0c/ecicceicienine 3 196.5 91.3 69.9
Sample No. 4:
E. K. Nelson 196.2 91.1 74.2
C. W. Harrison 193.5 90.4 70.9
194.7 89.6 73.5
E. O. Eaton 200.0 93.1 76.6
197.0 91.4 73.5
C. K. Glycart 211.5 100.4 75.8
208.5 96.8 75.6
A. W. Hanson 199.2 92.5 71.3
Maxamiumi tyariation() fo, -.s:)o.0.< 22-2. 211.5. Se 100.4 76.6
Mein ininmic variations. 5.21.46 5 ose'svenet= oy 0:2 193.5 89.6 70.9
COMMENTS BY ANALYSTS.
E. K. Nelson.—I believe that in pure oil the results by the proposed method must
more nearly give the true percentages of santalol because the acids present in small
amount in the oil (santalic and tetrasantalic acid) being of high molecular weight,
would not be likely to come over with steam, but would affect the results for santalol
in the official method.
On the other hand, assuming the presence of a santalol ester of one of them, (say of
santalol santalated), the santalol in such an ester would probably be determined by
170 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
the distillation method only if such an ester were converted into santalol acetate
in the process of acetylating. This seems probable as acetic acid must be much stronger
than the acids present in the oil. On the whole, there are more points in favor of the
Harrison distillation method.
E. O. Eaton.—Sufficient oil should be acetylized for several determinations, say
25 ce. The acetylized oil should be washed with hot water with mechanical agitation,
preferably a current of air. All the anhydride is not always converted into acetic acid
when the free acid is neutralized with sodium carbonate. The fused calcium chloride
should be rendered anhydrous by the analyst at a temperature below red heat. Baker’s
C. P. anhydrous calcium chloride was found to contain considerable water. Our labora-
tory had no facilities to reduce the volume of hydro-alcoholic oil solution after titration,
effective in less than 7 days, and so the standard 2-flask and trap method was used.
C. K. Glycart.—It is suggested that the directions in the Ninth Revision of the U. S.
Pharmacopceia for preparing the acetylated oil be stated in definite terms: the number
of washings with water; the amount of sodium carbonate test solution; also whether
the excess of sodium carbonate should be removed by further washings with water.
Evaporation in the Erlenmeyer flask was found to be slow even with the aid of an
electric fan (more than 10 hours). By transferring to a beaker with a large surface
evaporation was rapid.
A. W. Hanson.—Samples 3 and 4 are evidently adulterated, as shown by the Harrison
steam distillation method. It might be well to use a trap in making the steam distil-
lation to prevent the sulfuric acid from being carried over mechanically. The residue
after saponification is rather sticky and it is possible that by using a portion of alcohol
it could be more readily transferred to a steam distillation apparatus.
REVIEW OF ANALYTICAL DATA.
The results do not indicate as close agreement between the analysts
as desired, but the differences were no greater than occurred when
results were reported by the official method. It would seem that the
collaborators obtained even greater variations when using the U. S. P.
method. This is illustrated by Sample 4, where one analyst reported
100.4 per cent of santalol (U. S. P. method) and another reported 89.6
per cent by the same method. It is also evident that they did not en-
tirely understand the details of either method and considered further
explanation necessary. It appears, therefore, that if the present official
method is eventually retained, further details are necessary to clarify
it to insure uniform results.
Nelson points out very clearly the advantages which the distillation
method possesses over the present U. S. P. method when dealing with
pure oils, and the results on Samples 3 and 4 clearly show how unre-
liable are the results given by the U. S. P. method when assaying adul-
terated oils.
It is therefore evident that the present official assay method is not
satisfactory, as it does not give uniform results when applied by dif-
ferent analysts, nor does it give reliable results with adulterated oils.
The distillation method should be further studied with a view to work-
ing out further details, so that more uniform results can be obtained
1921] HARRISON: STUDY OF THE ESTIMATION OF SANTALOL 171
by different analysts, and establishing the minimum percentage of
santalol which pure oils should show when assayed by this method.
It was moved, seconded and adopted, that a representative of the
association be appointed to collaborate with the Revision Committee
of the United States Pharmacopceia and report progress at the next
annual meeting of the association.
The meeting adjourned at 5.30 p. m. for the day.
SECOND DAY.
TUESDAY—MORNING SESSION.
No general report on dairy products was made by the referee.
THE CRYOSCOPY OF MILK’.
By Julius Hortvet (State Dairy and Food Commission, St. Paul, Minn.),
Referee on Dairy Products.
The work included:
(1) A study of the cryoscopic method as applied to (a) samples of
milk obtained from individual cows and herds; and (b), a number of
series of samples consisting of milk mixed with known percentages of
water.
(2) A study of the literature on the cryoscopy of milk, with special
reference to (a) types of cryoscopes used by various investigators;
(b) conditions under which cryoscopic tests have been carried out;
(c) construction of thermometers; and (d), methods of manipulation.
The report included a fairly complete summary of the literature on
the cryoscopy of milk with a critical discussion of apparatus and pro-
cedures employed by various investigators. The report concluded with
a discussion of the tabulations of results obtained by collaborators and
attention was called to the relationships found to exist among results
obtained by various methods applied for the purpose of detecting added
water. A summary was given of results obtained on 75 authentic
samples. The report showed conclusively:
(1) That the cryoscopic method as applied to the examination of
milk is in need of standardization. In other words, it is necessary that
uniformity be secured respecting essential conditions, chiefly the follow-
ing, viz; the construction of the cryoscope, the method of testing and
correcting the thermometer, and the procedure.
(2) That the application of correction factors for all practical pur-
poses may be avoided by means of a carefully standardized procedure.
(3) That results obtained by means of the apparatus and procedure
described in the report indicate a narrow range of freezing-point values
as a characteristic property of milk.
(4) That the cryoscopic test is reliable as a method for the determina-
1 The complete report of the referee is not included in This Journal as it has previously been published in
J. Ind. Eng. Chem., 1921, 13: 198.
172
1921) HORTVET: THE CRYOSCOPY OF MILK 173
tion of added water in amount far below 10 per cent. When the freezing
point of the original whole milk is known, results are obtainable to
within an error not far from 0.5 per cent and when the freezing point
of the original milk (e. g., herd milk) is unknown, the addition of water
may safely be reported in amount as low as 3 per cent.
RECOMMENDATION.
_ It is recommended that the following cryoscopic method for the
examination of milk be given further study with a view to its adoption
as official:
CRYOSCOPE.
A cylindrical-shaped Dewar flask of 1 liter capacity, and 28 cm. internal depth,
surrounded by a metal casing, is tightly closed by means of a large cork of about 4 cm.
thickness. Through the center of the cork is fitted tightly a medium thin-walled
glass tube, 255 mm. in length by 33 mm. outside diameter. At one side of the cork is
inserted a narrow copper inlet tube, the lower end of which is formed into a perforated
loop near the bottom of the flask. At the opposite side is a metal tube of T-shape
construction and 6 mm. internal diameter, intended to afford escape for vapors, and
also for the introduction of volatile fluid into the apparatus. At the back portion of
the cork is fitted a control thermometer having a scale range of +20° to -30° C., with
the bulb extending nearly to the bottom of the flask. The freezing test tube is of thin
glass, about 250 mm. in length by 30 mm. outside diameter, and fits closely into the
larger tube which is sealed into the cork. In the rubber stopper of the freezing tube is
fitted the standard thermometer. The thermometer is constructed of sufficient length
to enable the insertion of the bulb near the bottom of the freezing test tube and at the
same time allow complete exposure of the scale above the stopper. At the right-hand
side of the thermometer a stirring device made of noncorrodable low conductivity
metal is fitted into the stopper through a short section of metal tubing. The lower
end extends nearly to the bottom of the test tube and is provided with a loop around
the outside of which are a number of pointed projections. At the left of the ther-
mometer is a freezing starter attachment inserted through an opening in the stopper
formed by means of a short section of metal tubing. This device consists of a non-
corrodable metal rod, at the lower end of which is a 10 mm. length opening for the
purpose of carrying a small fragment of ice. At one side of the cryoscope is installed
an air-drying arrangement which consists of a Folin absorption bulb inserted through
a tightly fitting stopper and extending nearly to the bottom of a large size test tube.
A short section of glass tubing is inserted through a second opening in the stopper and
is connected with the vaporizing tube which enters the tryoscope. Sulfuric acid is
poured into the drying tube to a level slightly above the inner bulb. At the opposite
side of the apparatus is arranged a drain tube for the purpose of conducting vapors
away from the operator. By means of a pressure and suction pump dry air may be
forced into the apparatus at a suitable rate and the mixed vapors conducted out through
the base of the drain tube into the sink. An adjustable lens is mounted in a suitable
position in front of the thermometer for the purpose of magnifying the scale.
174 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
PRESSURE —"
SuCTION
1
i
Fig. 1. Hortver Cryoscopr.
THERMOMETER.
The standard thermometer designed especially for testing milk is a solid-stem instru-
ment measuring a total length of 58 cm., with a scale portion measuring 30 cm. The
total scale range is 3°C., from +1° to —-2°C., each degree division being subdivided
into tenths and hundredths. The length of a degree division approximates to 1 deci-
meter, thus making the smallest subdivisions of such magnitude as to enable easy
observation and readings estimated to 0.001°C. The thermometer should be care-
fully standardized and calibrated in comparison with a Bureau of Standards tested
instrument.
The control thermometer should be tested in a bath of melting crushed ice for the
purpose of determining whether the zero mark on the scale is fairly correct to within
a small fraction of a degree.
DETERMINATION.
Insert a small caliber funnel-tube into the vertical portion of the T-tube at one side
of the apparatus and add 400 cc. of ether, previously cooled to 10°C. or lower. Close
the vertical tube by means of a small cork and connect the pressure pump to the inlet
tube of the air-drying attachment. Adjust the pump so as to pass air through the
apparatus at a moderate rate, which may be judged by the agitation of the sulfuric
acid in the drying tube. Continuous vaporization of the ether will cause a lowering
1921] HORTVET: THE CRYOSCOPY OF MILK 175
of the temperature in the flask, from ordinary room temperature to 0°C. in about
8 minutes. Continue the temperature lowering until the control thermometer registers
near -3°C. At this stage, by lowering a narrow-gauge, graduated glass tube into the
ether bath, then closing the top by means of the forefinger and raising to a suitable
height, an estimate can be made of the amount of ether necessary to add to restore
the 400 cc. volume. When the apparatus has been cooled to the proper temperature,
an additional 10-15 ce. of ether is onan average sufficient for each succeeding determi-
nation. Measure into the freezing test tube 30-35 cc. of boiled distilled water,
cooled to 10°C. or lower. Enough water should be added to submerge the thermometer
bulb. Insert the thermometer, together with the stirrer, and lower the test tube into
the larger tube. A small quantity of alcohol, sufficient to fill the space between the
two test tubes, will serve to complete the conducting medium between the interior of
the apparatus and the liquid to be tested. A sufficiently tight connection between
the inner and outer tubes is afforded by means of a narrow section of thin-walled rubber
tubing. Keep the stirrer in steady up-and-down motion at a rate of approximately
one stroke each 2-3 seconds, or even at a slower rate, provided the cooling proceeds
satisfactorily. Maintain the passage of air through the apparatus until the tem-
perature of the cooling bath reaches —2.5°C., at which time the top of the mercury
thread in the standard thermometer usually recedes to a position in the neighborhood
of the probable freezing point of water. Maintain the temperature of the cooling
bath at —2.5°C. and continue the manipulation of the stirrer until a supercooling of the
sample of 1.2°C. is observed. As a rule, by this time the liquid will begin to freeze,
as may be noted by the rapid rise of the mercury thread. Manipulate the stirrer
slowly and carefully three or four times as the mercury column approaches its highest
point. By means of a suitable light weight cork mallet tap the upper end of the ther-
mometer cautiously a number of times, until the top of the mercury column remains
stationary a couple of minutes. Taking necessary precautions to avoid parallax,
observe the exact reading on the thermometer scale and estimate to 0.001°C. When
the observation has been satisfactorily completed, make a duplicate determination,
then remove the thermometer and stirrer and empty the water from the freezing tube.
Rinse out the test tube with about 25 cc. of the sample of milk, previously cooled
to 10°C. or lower, measure into the tube 35 cc. of the milk, or enough to submerge the
thermometer bulb, and insert the tube into the apparatus. Maintain the temperature
of the cooling bath at 2.5°C. below the probable freezing point of the sample. Make
the determination on the milk, following the same procedure as that employed in
determining the freezing point of water. As a rule, howeyer, it is necessary to start
the freezing action in the sample of milk by inserting the freezing starter, carrying a
fragment of ice, at the time when the mercury column has receded to 1.2°C. below
the probable freezing point. A rapid rise of the mercury column results almost im-
mediately. Manipulate the stirrer slowly and carefully two or three times while the
mercury column approaches its highest point. Complete the adjustment of the mer-
cury column in the same manner as in the preceding determination; then, avoiding
parallax, observe the exact reading on the thermometer scale and estimate to 0.001°C.
The algebraic difference between the reading obtained on the sample of water and the
reading obtained on the sample of milk represents the freezing-point depression of the
milk.
To deduce the percentage of added water from the determined freezing point, use
Winter’s table! or the scale accompanying the cryoscope. The percentage of added
water (W) may also be calculated as follows:
ie A hich
At
1 Chem. News, 1914, 110: 283.
176 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
T =the average freezing point of normal milk (—0.550°C.); and
T’ =the observed freezing point on a given sample.
No report on moisture in cheese was made by the associate referee.
DETERMINATION OF FAT IN MALTED MILK.
By J. T. Ketsrer (Bureau of Chemistry, Washington, D. C.).
The determination of fat in malted milk by the official Roese-Gott-
lieb method and modifications thereof, has been the subject of more or
less collaborative study by the association since 1916 with wide varia-
tions in results. The writer, among others, last year also tested a direct
ether extraction process which produced the most concordant results so
far obtained. This method is objectionable, however, because of the
time consumed in its operation and, for this reason, attention has been
directed to a further study of a suitable modification of the official
Roese-Gottlieb method. Aside from the wide variations in the results
heretofore obtained by the official method, it would also appear that
the Roese-Gottlieb method gives figures slightly below the actual per-
centage of fat present.
The work here reported consists of a comparison of the regular official
method with the same method omitting the use of ammonia. While
the results are not entirely satisfactory, it is believed they are sufficient
to warrant further consideration of this proposed modification.
Comparative resulls on the delermination of fat.
(Results calculated to a water-free basis.)
OFFICIAL ROESE-GOTTLIEB METHOD OMITTING
OFFICIAL ROESE-GOTTLIEB METHOD AMMONIA
per cent per cent
Sample A
8.655 8.526
8.577 8.676
8.569 8.680
8.469 8.710
ue 8.750
Average......8.574 8.668
Sample B
7.568 8.032
7.829 7.923
7.920 7.763
7.998 7.935
7.750 Beets
Average......7.813 7.913
1921] KEISTER: DETERMINATION OF FAT IN MALTED MILK 177
It will be noted that the results in both cases show an average about
0.10 per cent higher by the method in which the use of ammonia was
omitted. It is also noted that more concordant results were obtained
in the case of Sample A than with Sample B, which would indicate a
greater difficulty in extracting the fat from some brands of malted milk
than others.
Results obtained last year on a collaborative sample were not satis-
factory by the method omitting the use of ammonia, because of the
formation of an emulsion which almost filled the extraction tube. It is
believed that this condition was principally due to the proportions of
water and alcohol used—about 8 cc. of water to 5 cc. of alcohol. In the
work here reported, 10 cc. of water and 10 cc. of alcohol were used and,
in some cases, when the third extraction was made if an emulsion was
inclined to form, a further addition of 1 or 2 cc. of alcohol was made
with satisfactory results.
To obtain the most satisfactory results with this modification the
following points should be observed:
1. Use about a 1-gram sample, add 10 cc. of water and rub thoroughly
with a glass rod in a small beaker until all visible particles of the powder
have disappeared and a homogeneous emulsion is formed. This is very
necessary; otherwise, when the alcohol is added, lumps are formed
which it is difficult or impossible to break up, thereby rendering the
extraction incomplete. This condition is probably due to the fact that
dextrine is soluble in water but insoluble in alcohol. Therefore, it must
be brought in complete solution with the water before the addition of
alcohol to avoid the formation of lumps.
2. It is necessary to shake the extraction tube longer (at least 1
minute) than is required in the case of milk powder or other milk product.
3. A third extraction is always necessary.
4. A slight amount of insoluble material is sometimes obtained in the
third extraction, which must be determined and the proper correction
made.
CONCLUSION.
-The fat is extracted from malted milk with greater difficulty than
from any other milk product, but it is believed that by the observance
of the above-noted points and with a little experience the Roese-Gott-
lieb method without the use of ammonia will completely extract the
fat from this product.
178 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
REPORT ON FATS AND OILS.
By R. H. Kerr (Bureau of Animal Industry, Washington, D. C.),
Referee.
The work consisted of a comparative study of the Hanus and Wijs
methods for determination of the iodine number. As the relative merits
of these two methods have been the subject of more or less controversy,
and as most of the comparative tests recorded have been made by some
one previously familiar with one or the other of the two methods, the
making up of the solutions was entrusted to an assistant who was not
familiar with either method but who was thoroughly fitted by training
and experience to carry out the work. His report is of interest and is
as follows:
COMPARISON OF THE WIJS AND HANUS METHODS.
(Analyst, A. L. MEHRING.)
The Wijs solution was prepared by mixing equivalent amounts of solutions of chlorine
and iodine in glacial acetic acid. The chlorine solution was prepared by passing pure,
dry chlorine into glacial acetic acid. The iodine solution was prepared by dissolving
15 grams of iodine in 600 ce. of glacial acetic acid. The strength of both was deter-
mined by titration against a standard sodium thiosulfate solution. A sufficient amount
of iodine solution for 1 liter of Wijs solution was then mixed with its exact equivalent
of chlorine solution and made up to a volume of 1 liter with glacial acetic acid. The
Hanus solution was made according to the official method of the association. Two
portions of each fat or oil were run in duplicate by the official method with each solu-
tion. Manipulation was exactly the same in each case except for the difference in
time allowed for absorption, 15 minutes for the Wijs and 30 minutes for the Hanus
solution. Following are the results:
TABLE 1.
Todine numbers obiained by the Wijs and Hanus methods.
(Analyst, A. L. Mehring.)
METHOD CORN OIL COTTONSEED | HYDROGENATED | pune LARD Omer on
OIL TALLOW
\Whiiseaceude 119.69 107.97 37.97 61.81 83.77
Wis yeeros on 122.01 107.51 38.06 61.16 83.47
anus eee 118.54 105.11 39.31 62.43 80.52
Efanus)).)i01-'s 118.58 105.52 39.26 61.75 80.26
The results obtained with the Hanus solution showed a slightly less variation than
those with the Wijs. The numbers obtained for oils giving the highest values were
uniformly higher with the Wijs than with the Hanus solution. The greater length of
time required for the absorption of the Hanus solution is a factor only when a single or
very small number of determinations is made at the same time. The amount of labor
involved in generating and washing the chlorine is a disadvantage in making up the
Wijs solution, inasmuch as the corresponding bromine for the Hanus solution may
easily be obtained ready for use.
1921] MAINS: REPORT ON BAKING POWDER 179
Comparative tests were also made by an experienced analyst who was
thoroughly familiar with the determination of the iodine number by
the Hanus method. The results obtained are as follows:
TABLE 2.
Todine numbers obtained by the Wijs and Hanus methods.
(Analyst, J. B. Martin.)
DESCRIPTION OF SAMPLE | HANUS wiis
[Lovet ie ce a oe pa eth a | 60.33 63.14
59.91 63.36
Hydrogenated beef fat.............. 39.15 37.67
39.04 37.62
MOVE TOM re. saya. cte co aciejers,o oe wie ules tiayay as 81.51 83.45
80.83 83.69
RGGERORSEEM OM ss, ora chy peace crete xicre- cies 105.34
105.71
WGherrrear ON eps pes ara ce se ayn ePos lusts aiiecs) oh cimus ete 121.47
12).68
RECOMMENDATION.
It would appear from these results that the Hanus and Wijs methods
give fairly comparable results. If the results by either method are
taken as a standard, those obtained by the other method would have to
be regarded as somewhat erratic. The results show no reason for
regarding either method as superior to the other. It is recommended,
therefore, that the Hanus method be continued as the official method
with the Wijs method as the tentative method of the association, as
at present.
REPORT ON BAKING POWDER.
By G. H. Mars (Bureau of Chemistry, Washington, D. C.), Referee.
The work was upset by the midseason resignation of the referee,
H. E. Patten, and some time elapsed before the writer was asked to
look after the work for the remainder of the year.
The recommendations for 1919 called for a further study of the
electrolytic method for the determination of lead, of minor details of
the fluoride method, and of methods for the determination of the neutral-
izing strength of baking acids. The work has been necessarily limited
to collaborative lead determinations, using the electrolytic method, and
to a preliminary survey of methods for determining neutralizing values.
180 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
DETERMINATION OF LEAD BY THE ELECTROLYTIC METHOD.
The samples sent to the collaborators were made up to specifications
from specially purified commercial materials, prepared through the
courtesy of E. W. Thornton of the R. B. Davis Baking Powder Com-
pany, Hoboken, N. J. One set consisted of a straight mono-calcium
phosphate powder, the other of a combination phosphate and sodium
aluminium sulfate powder. Each type contained 25 per cent by weight
of sodium bicarbonate, and the total lead content (added in the form of
sulfate) was 50 parts per million.
Collaborators were requested to use the tentative electrolytic method!
except that they were given the option of substituting a colorimetric
for a gravimetric determination in the final step.
Relatively few of the collaborators presented reports. The results
obtained are shown in the following table. The figures for each separate
determination are presented, the amount of lead found being reported as
the nearest whole number of parts per million:
Determination of lead in baking powder by the electrolylic method.
LEAD FOUND BY ANALYSIS
COLLABORATOR Phosphate powder Combination phosphate-sodium
(Lead content: 50 parts per aluminium sulfate powder. (Lead
million) content: 50 parts per million)
parls per million parls per million
A. H. Fiske and A. L. Thayer,
Rumford Chemical Works, 9 15
Providence] tae ene 9 15
A.Malmstrom, Wilckes-Martin- 26 17
Wilckes Co., Camden, N. J. 26 26
32
32
W. E. Stokes and D. J. Kap-
lan, Royal Baking Powder 42
Co., New York, N. Y...... 23 45
A. H. Fiske used a modification of the method in which the organic
matter was destroyed by ignition with magnesium nitrate before the
preparation of the solution for electrolysis. A. Malmstrom found that
with the combination phosphate-sodium aluminium sulfate powder a
more satisfactory medium for electrolysis was obtained by using 50
grams of the sample in place of the 100 grams specified. Stokes and
Kaplan recommend that the period of electrolysis be extended from &
to 15 hours.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 287.
1921] MAINS: REPORT ON BAKING POWDER 181
In general, the results of each collaborator fall short of the actual
lead content, and do not agree very well with those of other collabora-
tors. However, it will be noted that each collaborator, when running
his samples by his own particular technique, secured consistent results.
This would seem to indicate that the method requires a closer regulation
of conditions during electrolysis, especially with regard to acidity of
solution, in order to insure the deposition of all of the lead during the
electrolysis. From theoretical electro-chemical considerations, in order
to obtain the last traces of lead, the hydrogen-ion concentration of the
solution for electrolysis should be reduced as low as practicable, and
means taken to increase the hydrogen over-voltage at the cathode.
For this purpose a study of the substitution of other metals, particu-
larly nickel and chromium, for platinum as the cathode is suggested.
METHODS FOR THE DETERMINATION OF THE NEUTRALIZING
STRENGTH OF BAKING ACIDS.
The present official method! for acidity of cream of tartar and its
substitutes does not give consistent results when applied to the determi-
nation of the neutralizing strength of commercial acid phosphates, and
it was recommended in 1919 that a study be made of this question.
A number of inquiries have been received during the past two years for
standard methods for the determination of the neutralizing value, and
several of the manufacturers have expressed a willingness to cooperate
in this study. A general survey of the methods that have been sub-
mitted shows them to be quite similar except for some details which
cause the big differences in the values obtained.
The writer has obtained fairly consistent results with certain types of
mono-calcium phosphates, using the following modification of the
available methods:
Weigh 0.84 gram of the phosphate into a 250 cc. beaker, add 125 cc. of water, and a
large amount of phenolphthalein indicator (10-15 drops of the ordinary solution).
Titrate with 0.5 N sodium hydroxide to a faint pink; heat to boiling; boi) for 1 minute,
and continue titrating while hot till a permanent pink is reached. The total reading,
multiplied by 5, equals the neutralizing value in terms of parts of NaHCO; per 100
parts of phosphate. -
Other methods call for the addition of salt solution to prevent hydroly-
sis, the addition of sodium hydroxide in excess and back titration with
hydrochloric acid, or the use of sodium carbonate instead of sodium
hydroxide. The ionization constants of phosphoric acid do not indicate
any necessity for protection against hydrolysis, but such details and
others that may be proposed should form part of the study for the
coming year.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 281.
182 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
PRESENT STATUS OF BAKING POWDER METHODS.
The writer must say a word of appreciation for the large amount of
valuable work on baking powder that the former referee, H. E. Patten,
together with his collaborators, has done during the past four years.
While there will always be room for improvement, the baking powder
methods are today in very good shape. There has been especially
valuable collaboration on the part of the larger manufacturers of baking
powders and ingredients, both in the development of methods and in the
improvement of the purity of their products. Valuable work has also
been carried on by a number of official and commercial chemists. It is
to be hoped that the incoming referee will enjoy the same helpful co-
operation.
RECOMMENDATIONS.
It is recommended—
(1) That a further study be made of the Chittick method! for the
determination of lead in baking powders with the view to establishing
it as a tentative method.
(2) That a study be made of the details of the electrolytic method
for the determination of lead in baking powder with special reference to
the acidity conditions during electrolysis.
(3) That a study be made of methods for the determination of the
neutralizing strength of baking acids.
(4) That the paper entitled, ““Determination of Total Carbon Dioxide
in Baking Powder’, presented by C. 8S. Robinson, and given below, be
referred to the referee on baking powders and baking chemicals for
study of the method contained therein.
DETERMINATION OF TOTAL CARBON DIOXIDE IN
BAKING POWDER’.
By C. S. Ropinson’ (Agricultural Experiment Station, E. Lansing, Mich.).
The Association of Official Agricultural Chemists recognizes but one
type of method for the determination of total carbon dioxide in baking
powder, i.e., the absorption type. Two variations, Knorr’s! and Heid-
enhain’s® have been adopted as official while any one which gives accurate
results with calcite may be included in the class of tentative methods.
The object of the present article is to call attention to certain defects in
1 J. Assoc. Official Agr. Chemists, 1920, 4: 218.
2 Journal Article No. 17 from the Chemical Laboratory of the Michigan Agricultural College Experiment
Station. Published by permission of the Director of the Agricultural Experiment Station.
3 Presented by A. J. Patten.
4 Assoc. Official Agr. Chemists, Methods. 2nd. ed., 1920, 277.
5 Ibid., 279; J. Am. Chem. Soc., 1896, 18: 1.
1921] ROBINSON: TOTAL CARBON DIOXIDE IN BAKING POWDER 183
the descriptions of these methods and also to suggest the adoption of
another type of method which possesses marked advantages over those
at present in vogue.
In the absorption type of method the carbon dioxide is liberated from
the sample by dilute acid and is swept, by means of a current of air,
through vessels charged with alkali which absorb it. The increase in
the weight of the contents of the vessels is the measure of the carbon
dioxide absorbed.
The apparatus consists of the following parts:
(1) A vessel for removing carbon dioxide from the air current used
to expel the carbon dioxide produced from the sample.
(2) <A reaction vessel into which the sample is weighed and in which
it is decomposed. This vessel is fitted with a dropping funnel for intro-
ducing the acid and a condenser to minimize the escape of water vapor.
(3) <A device for drying the stream of air and carbon dioxide.
(4) The absorption vessel or vessels.
(5) A drying arrangement to prevent the backward diffusion of
moisture into the absorption vessels.
(6) An aspirating device.
The details of the apparatus are capable of limited variation. A
tower of soda lime may be used for (1) or any of the usual forms of dry-
ing tubes filled with the same material or a wash bottle filled with a
strong solution of alkali. Calcium chloride U-tubes or washing bottles
filled with concentrated sulfuric acid may be used for (3). The carbon
dioxide may be absorbed in potash bulbs containing a solution of pot-
assium hydroxide or in U-tubes or other vessels filled with soda lime.
Either of the devices used for (8) may also be used for (5) while a me-
chanical pump, water pump or aspirator bottle may serve to draw the
air through the apparatus. Any of these various forms may be used
interchangeably, as described, provided suitable precautions are observed.
The two arrangements prescribed in the official methods are in reality
but two variations of the above-described units.
The following criticisms of the official methods seem to be justified
from the author’s experience. Since the methods are essentially alike,
differing only in the details of the set-up, it seems unnecessary to differ-
entiate between them to the extent of describing them separately.
The real fault, however, lies in the directions for the use of Knorr’s
apparatus. These are not only entirely inadequate but, at least in the
writer’s experience, positively misleading in one or two respects. Thus,
it is prescribed that the acid used to decompose the sample shall be
hydrochloric acid having a density of 1.1. The writer’s experience has
been that acid of this concentration invariably gave off hydrochloric
acid gas which was absorbed in the absorption vessels, giving high
184 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
results. A wash bottle containing silver nitrate placed ahead of the
absorption train always showed a deposit of silver chloride. Possibly
the boiling of the liquid in the flask and the strength of the air current
can be so regulated as to overcome this difficulty but it is so much
easier to dilute the acid with an equal volume of water to a concentra-
tion which can be used with perfect safety that it seems inadvisable to
maintain the original directions.
The directions for expelling the carbon dioxide are equally misleading.
The rate of aspiration recommended is “about 2 bubbles per second”’
and the length of time required to free the apparatus from carbon
dioxide is defined by the direction to “‘allow the apparatus to cool with
continued aspiration” after boiling the liquid for a few minutes “after
water has begun to condense’”’. With the apparatus used by the writer,
this period would embrace about 15 to 20 minutes which is entirely
insufficient. The rate of aspiration is also indefinite as potash bulbs
have been connected in a series in the same train which showed rates of
aspiration varying through a range of 100 per cent or more when judged
by the above standard.
But little fault can be found with Heidenhain’s modification except
that the original description of his apparatus and procedure, published
a quarter of a century ago, is still adhered to in spite of the fact that
some of it is obsolete.
By using Heidenhain’s technique and general form of apparatus,
excellent results can be obtained and, in fact, the conclusion seems
justified that, irrespective of the apparatus used, the reliability of the
results varies directly with the closeness with which his directions are
followed. The writer has found that with but few exceptions all of
the precautions advised by Heidenhain must be taken if one is to obtain
reliable results by the absorption method. The exceptions for ordinary
work are the inclusion of the absorption vessels in a glass case and the
making of corrections for the temperature and pressure at the time of
weighing.
The writer would suggest, however, the use of a flowmeter for con-
trolling the rate of aspiration. He used the type adopted by the
American University Experiment Station! which can be made by any
one having an elementary knowledge of glass blowing. The greatly
increased ease and accuracy with which one can control the process
makes the time required for its manufacture well spent. Too much
care can not be taken in controlling this factor in the method under
discussion. By careful observation, the writer found that a difference
in rate of less than 5 cc. per minute may cause appreciable errors in the
results. With a flowmeter connected in the train next to the aspirating
bottle one can tell at a glance at any time just how fast the aspiration
1 J. Ind. Eng. Chem., 1919, 11: 623.
a 2 tn
1921] ROBINSON: TOTAL CARBON DIOXIDE IN BAKING POWDER 185
is proceeding without taking the time to make the necessary measure-
ments required to ascertain the rate by Heidenhain’s method.
The official standard of 3 liters of air as a requisite amount to remove
completely the carbon dioxide is not a safe one. Neither can the
amount be ascertained for any given apparatus, as Heidenhain has
suggested, without adding a factor of safety which makes the method
of aspirating to constant weight preferable. With the apparatus
employed by the writer, 3 liters were about the minimum amount of
~ air required to remove the usual quantities of carbon dioxide generated
but at times as high as 6 liters of air had to be drawn through before
the weight of the absorption vessels became constant. If a figure for
constant use had been selected it would have been necessary to choose
about 6 liters as the amount to be used. It is quicker to interrupt the
aspiration at the end of the third liter and after the passage of each
liter thereafter to make a weighing than to always pass 6 liters of air
through the apparatus and call the removal complete.
Another precaution which should not be neglected when using soda
lime for absorbent purposes is to have some calcium chloride in the
tube where the air enters and more where it leaves. In order to absorb
the carbon dioxide efficiently, soda lime must be moist and this moisture
must be prevented from escaping. In fact, the writer has found that,
as Heidenhain has stated, there is little danger of a loss of carbon dioxide
through its being swept through two soda-lime tubes but there is a real
danger of moisture being carried from the last soda-lime tube if in-
sufficient calcium chloride is present or if the safe rate of aspiration is
exceeded.
By attending to these precautions, results have been obtained which
leave nothing to be desired from the standpoint of accuracy. The
writer has tried both Heidenhain’s apparatus, as originally described
(with the exception of the condenser), and an arrangement in which
his long calcium chloride U-tubes were replaced by the more convenient
and common potash bulbs containing sulfuric acid, giving in effect a
modified Knorr set-up. This makes a more convenient arrangement
and one composed of units available in any well-equipped laboratory.
In the light of experience with the present official methods, the writer
feels that it would be advisable to eliminate that portion of them dealing
with the determination of total carbon dioxide in baking powder and to
substitute the following:
TOTAL CARBON DIOXIDE.
Absorption Method.
REAGENTS.
(a) Potassium h ydrozide solulion.—Dissolve 25 ams of potassium hydroxide in
50 ec. of water.
186 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
(b) Soda lime-—Granulated to pass a sieve having 9-12 meshes to the inch and
freed from dust by sifting.
(Cc) Calcium chloride ——Granulated to pass a sieve having 9-12 meshes to the inch,
sifted to free it from dust, dehydrated at 200°C. and saturated with carbon dioxide
before use.
(d) Sulfuric acid—Ordinary concentrated acid (sp. gr. 1.84).
(e@) Approximately 10% hydrochloric acid.
APPARATUS.
Fic. 1. APPARATUS FOR THE Da&TeRMINATION OF CARBON Droxipe.
This consists of a flask B, Fig. 1, of 100-200 cc. capacity fitted with a dropping
funnel, the stem of which reaches to the bottom of the flask and an outlet tube forms
the inner tube of a reflux condenser. The stem of the dropping funnel should be drawn
out to a tip and be bent upwards to prevent the advent of gas. All joints should be
ground.
Standard U-tubes for holding solid absorbents (calcium chloride and soda lime)
and potash bulbs of any suitable type such as Geissler, Gomberg or Liebig, for holding
liquid absorbents (sulfuric acid and potassium hydroxide solution).
An aspirating device, such as a bottle arranged as shown in the figure, a suction
pump or a mechanical vacuum pump.
A flowmeter having a range up to 50 cc. per minute is desirable. Otherwise, a
graduated cylinder and watch must be used to measure the rate of aspiration.
Burners, ringstands, etc.
A drying tower filled with soda lime may be used for purifying the air which expels
the carbon dioxide but either of the means used for absorbing the carbon dioxide from
the sample itself may be substituted for it.
The genera] arrangement of the parts is shown in the sketch but it is to be under-
stood that sulfuric acid and calcium chloride in the appropriate containers may be
used interchangeably for the purpose of absorbing moisture, while either soda lime or
potassium hydroxide solution may serve as absorbents for carbon dioxide. As shown
in Fig. 1, A is the tower filled with soda lime for removing carbon dioxide from the air
used in expelling the generated carbon dioxide into the absorbing apparatus; B is the
reaction flask; C represents the potash bulbs containing sulfuric acid used to dry the
mixture of air and carbon dioxide (two units should always be used, one to take care
of the bulk of the moisture which comes through the condenser and a second to remove
any traces which may escape the first one); D is the carbon dioxide absorbing apparatus;
E is a drying tube to prevent the backward diffusion of moisture into D; F is a flow-
1921] ROBINSON: TOTAL CARBON DIOXIDE IN BAKING POWDER 187
meter; and G an aspirating device. The bottle is graduated to read in half liters and
should have a capacity of 6 liters or more.
Precautions should be taken with the absorbing mechanism to prevent the escape
of moisture and to insure complete absorption of the carbon dioxide. If soda lime is
used it should be cortained in two tubes. In the first one, at the end where the carbon
dioxide enters, about 1 inch of calcium chloride should be placed. The rest of this
tube is filled with soda lime, as is the arm of the second tube adjacent to it. The arm
of the latter by which the air leaves is filled with calcium chloride. If potash is used
as the absorbent, the bulbs should either be supplied with an attached calcium chloride
tube or if one of the older types is used, a second unit filled with sulfuric acid which is
weighed before and after each determination should be provided.
DETERMINATION.
In order to find the allowable rapidity of the air current employed during the determi-
nation, proceed as follows: Charge the apparatus exactly as for an analysis, leaving
out the carbonate. Begin to aspirate at the rate of about 50 cc. per minute. After
2 liters have been aspirated, weigh the absorption vessels. If they have lost weight,
repeat the experiment with a rate of 40 cc. per minute, and so on until the weight of
the vessel remains constant. If the work has been properly conducted the first unit
will have lost just as much as the second will have gained. In making actual analyses
do not exceed the safe speed thus found.
Weigh the absorption vessels after having opened them momentarily to equalize
the air pressure. Connect them in place in the apparatus and test the tightness of
the joints by closing the inlet to A, with all intermediate cocks open, carefully opening
the cock between F and G, G being filled with water and in equilibrium with the outlet
cock already open. If there is no leak, the liquid in the flowmeter will shortly indi-
cate no movement of air. Then close the cock on C adjacent to B and introduce the
sample into the latter, which should be dry. Replace the dropping funnel and put
into it a sufficient excess of 10% hydrochloric acid so that it may be boiled in the flask
without danger of cracking the glass. Connect the drying tower, A, with the rest
of the apparatus and carefully open the cock between B and C. When the flowmeter
shows the passage of no more air, admit the acid slowly into the flask, observing the
flowmeter to see that the carbon dioxide is not evolved too rapidly. When all of the
acid has run from the funnel into the flask, close the stop-cock in the stem of the funnel,
start the water in the condenser, and heat the flask with a small flame until no more
gas is evolved. (The use of sulfuric acid wash bottles, as shown in Fig. 1, for drying
the gas instead of calcium chloride tubes aids in controlling this operation as the carbon
dioxide at times constitutes such a high percentage of the gas entering the train that
there is no passage of sir through the flowmeter.) Then with a small flame under
the flask to keep the liquid at the boiling point, open the cock in the dropping funnel
enough to permit air to be aspirated through the apparatus at about half the rate
found to be safe. After the bulk of the carbon dioxide has been expelled, increase
this rate to the maximum allowable speed. When 3 liters have passed through, as
indicated by the marks on the aspirator bottle, close the cock between F and G and
those on the absorbing vessels. Remove and weigh the latter and replace them in the
train. Pass another liter of air through and weigh again, repeating the process until
there is no net gain after passing a liter of air through the apparatus, i. e., until one
tube gains just as much as the other loses.
The net gain in weight of the absorption vessels is due to carbon dioxide and its
percentage of the sample is calculated in the usual manner.
But however much may be said of this method from the standpoint of
accuracy it must be admitted that it is cumbersome and _ time-con-
188 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
suming. Asa substitute for it a method is now proposed which requires
but one piece of apparatus into which the sample is weighed and in which
it is decomposed and the volume of carbon dioxide is measured. It
may be allowed to stand indefinitely and then used at once without
further preparation than the greasing of the stop-cocks.
The number of analyses which can be made in a given time is de-
termined almost entirely by the rapidity with which the analyst can
weigh samples, the time required for the determination being a matter
of minutes. It is easily possible to make a complete estimation of the
total carbon dioxide in a baking powder by this method in about 5
minutes, including weighing the sample, decomposing it, measuring the
carbon dioxide liberated and calculating the results.
The accuracy of the method is at least equal to that of the more
complicated absorption methods. Because of its greater simplicity, the
fact that there are fewer weighings to make and in general less possible
sources of error it is essentially more accurate than the methods at
present in vogue.
As originally designed!, it was applicable only to the analysis of
carbonates in solution but in the modified form later described? it can
be used equally well for solid material. The apparatus is shown in
Fig. 2.
It consists of a 10 cc. buret haying the upper 2 cc. graduated in 0.02 cc. and the
remaining 8 cc. graduated in 0.05 cc. The upper end of this buret is closed by a 3-way
stop-cock having one arm bent as illustrated and the other one sealed to a cup holding
_ 5-10 ce. graduated to 5 cc. in 0.5 cc. The lower end of the buret is sealed to a bulb
of such size that the whole apparatus will have a capacity of 50 cc. from the stop-cock
A to a mark between the bulb and the stop-cock B. The openings in the stop-cocks
B and C should be large, as mercury is forced through them.
The stopper D should be as close to B as convenient in order to reduce the space
above it and the total capacity of the stopper and right-hand tube F to which the
stopper is attached should be about 5 cc. The stopper should be hollow and the end
should he open. It should be set at right angles to F.
The lower outlet of C is attached by a piece of heavy-walled suction tubing to a
leveling bulb filled with mercury.
The following is the technique employed in making a determination: For materials
so high in carbon dioxide that a sample of less than 500 mg. will liberate not over 10 cc.
of gas the hollow stopper serves as a weighing bottle and the material is weighed into
it, the tube being filled with mercury up to the mouth of D to reduce the air space
which must subsequently be evacuated. For carbonate-poor substances, the sample
is weighed into the tube F, being introduced by means of a test-tube funnel.
The whole apparatus except the right-hand tube F between B and C (but including
the right-hand hole in C) is then filled with mercury. With the stop-cock A closed
and the connection open between B and C through the tube £, the leveling bulb is
lowered to such a position that the mercury level drops below C, evacuating the buret,
bulb, etc. (This is done conveniently by means of a heavy cord of proper length
attached to the bulb by one end and by the other to the support holding the apparatus.)
1 J. Biol. Chem., 1917, 30: 347.
2 Soil Science, 1920, 10: 41.
1921] ROBINSON: TOTAL CARBON DIOXIDE IN BAKING POWDER 189
2.17 COLE.
Gcc.in OOSee.
Fic. 2. APPARATUS FOR THE GASOMETRIC DETERMINATION OF CARBON DIoxIDE.
(By courtesy of Soil Science.)
190 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
The cock B is then turned through a complete revolution establishing, as connection
is made momentarily between them, equilibrium in gas pressure in the tube F and the
evacuated space above it. The leveling bulb is then raised to a position above A and
this cock opened, allowing the escape of the entrapped air. Repeating this operation
several times reduces the air in the apparatus to a negligible amount. The sample is
now held in a gas-free apparatus.
Approximately N hydrochloric acid is next poured into the cup above A and exactly
2.5 cc. admitted to the buret, the leveling bulb being held about even with the stop-
cock B. The bulb is then lowered to the lowest position and the mercury allowed to
flow out through the tube E, the cock B being closed while a little mercury still remains
above it. If the sample is of such material that it is still contained in D, the mercury
in the tube below it is now permitted to flow out through C, which is closed, leaving a
few drops above this cock to seal it. B is then turned to allow the acid to run into
the tube F.
The sample, if not originally weighed into the tube, is shaken out of the stopper
into the acid. No precautions need be taken to moderate the violence of the reaction
as any particles of the sample carried up into the bulb will be decomposed later. The
apparatus should be shaken so that all of the sample is washed out of the stopper D
and down from the walls of the tube.
When the evolution of gas has stopped, the communication between the leveling
bulb and F is opened and the stopper and tube completely filled with mercury up to
the 50 cc. mark. B is then closed and the apparatus shaken with a rotary motion in
such a way that the liquid is distributed in a thin layer about the walls of the bulb
until equilibrium between the gas in solution and that in the free space is attained.
The liquid is next quickly drawn back into F’, by lowering the leveling bulb and open-
ing B which, however, is closed before any gas passes into it. C and B are finally
turned to allow mercury to flow up into the buret through E while the acid is retained
in F’, the leveling bulb is raised until the mercury surface in it is on a level with that
in the buret and the gas volume read. A fraction of a cc. of acid will unavoidably be
held in the buret. This will cause no appreciable e:ror in the results but care must be
taken to read the gas volume at the surface of this liquid and not at the mercury sur-
face, although it is the levels of the two mercury surfaces that are equalized.
The temperature and barometer readings should be noted at the time of reading the
gas volume which affords sufficient data to permit the calculation of the weight of
carbon dioxide obtained from the sample by means of tables!. For a complete dis-
cussion of the principle of the method the reader is referred to the original article.
Suffice it to say that it depends upon the generation of gas in a Torricellian vacuum,
the measurement of that portion of the gas contained in a volume of 47.5 cc. in equi-
librium with the gas dissolved in 2.5 cc. of water and the calculation of the total volume
of gas from its known solubility in water at the temperature of the determination,
correction being made for the air dissolved in the 2.5 cc. of water. (This may, how-
ever, be determined for each analysis by introducing a few drops of alkali into the ap-
paratus through the cup after reading the total volume of gas. The carbon dioxide
will, of course, be absorbed leaving the air, the volume of which may then be read off
after equalizing the mercury levels.)
Table 1 gives the results of several determinations by the two methods
on a sample of calcite and three brands of baking powder. It shows
the usual magnitude of experimental error to be expected in each as
well as the agreement between the two methods.
1 J. Biol. Chem., 1917, 30: 317, 360.
made
Pewee,
|
1921] LOURIE: REPORT ON EGGS AND EGG PRODUCTS 191
TABLE 1.
Comparison of absorption and gasometric methods for determining carbon dioxide.
CARBON DIOXIDE CARBON DIOXIDE
SAMPLE _ SAMPLE
Absorption | Gasometric Absorption | Gasometric
per cent per cent per cent per cent
Calcium Carbonate.) 43.95 43.92 Baking Powder, 13.41 13.39
43.85 43.95 Sample No. 2.. 13.36 13.28
44.02 43.88 en 13.39
Baking Powder, ASSIS 13.16 Baking Powder, 16.91 16.97
Sample No. 1... 12.97 13.18 Sample No. 3.. 17.00 16.89
Sees 13.23 eee 16.92
CONCLUSIONS.
It has been found impossible to get accurate results with the Knorr
method, as prescribed in the official methods. This is due to two
causes—the high concentration of acid designated and the time specified
for expelling the liberated carbon dioxide. Hydrochloric acid was
invariably carried over into the absorption vessels yielding high results
unless the acid was considerably diluted. Aspiration continued only
during the period of cooling is entirely insufficient to completely expel
all of the carbon dioxide into the absorption train.
Following Heidenhain’s technique, excellent results may be obtained
with either his or Knorr’s form of apparatus.
Equally good results can be obtained with the gasometric method
described, page 188, which requires but a small fraction of the time
necessary to carry out a determination by the absorption method.
In the light of the above facts, it seems desirable to revise the official
methods of this association.
No report on soft drinks was made by the referee.
REPORT ON EGGS AND EGG PRODUCTS.
By H. L. Lourre (U. S. Food and Drug Inspection, Station, U. S. Ap-
praiser’s Stores, New York, N. Y.), Referee.
In 1919 it was recommended that a further study be made of the
methods for the determination of lecithin-phosphoric acid in dried eggs
and alimentary pastes. A preliminary investigation was started by
the referee and M. G. Wolf, of the New York Food and Drug Inspec-
tion Station, to determine the accuracy of the present method, com-
monly known as the Juckenack method, and to devise, if possible, a
method which would give a greater recovery of the lecithin-phosphoric
acid.
192 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
In conversation with the referee, C. L. Alsberg suggested that the
phosphatids of wheat may be more soluble in methyl alcohol than
ethyl alcohol. The work here reported is based largely on his suggestion.
This investigation has only reached the preliminary stage, but the
writer is able to report that ethyl alcohol does not dissolve all of the
phosphatids of flour or egg. Thirty grams of flour, which had been
dried for 6 hours in a vacuum oven at a temperature of 50°C., vacuum
283 inches, were extracted for 10 hours with absolute methyl alcohol
and absolute ethyl alcohol. It was found that the amount of lecithin-
phosphoric acid recovered in the case of the methyl alcohol was 0.028
and 0.025 per cent and, in the case of the ethyl alcohol, 0.016 and 0.014
per cent.
Another series of determinations was made in the same way and
nitrogen was determined on the extracted matter. In the case of the
methyl alcohol 0.067 per cent of nitrogen was obtained and, in the case
of ethyl alcohol, 0.033 and 0.028 per cent.
A mixture was made of 29.4 grams of flour with 0.06 gram of whole
egg. This material previous to mixing had been desiccated for 6 hours
at 50°C., vacuum of 284 inches. After extraction for 10 hours the
lecithin-phosphoric acid was determined and, in the case of the methyl
alcohol, gave 0.043 and 0.045 per cent and, in the case of ethyl alcohol,
0.024 and 0.023 per cent, making the proper correction for the blanks
obtained in both the methyl and ethyl alcoholic extractions. This 2
per cent egg mixture would yield 0.0175 per cent of phosphoric acid in
the case of methyl alcohol as compared with 0.0085 per cent of phos-
phoric acid for ethyl alcohol.
A modification by H. B. Mead of the method used at the New York
Food and Drug Inspection Station for the determination of zine in
dried egg products, which has been used for the past year and a half
in routine regulatory work and has given the utmost satisfaction, is
as follows:
Modified Method for Determination of Zinc in Egg Products.
Place 25 grams of the well-mixed sample in an 800 cc. Kjeldahl flask; add 5 grams
of zinc-free potassium sulfate, 3-4 glass beads to prevent bumping, 30 cc. of concen-
trated sulfuric acid, in the case of yolks or whole eggs (25 cc. of the acid in the case of
albumins); and 30 cc. of concentrated nitric acid. Do not heat. When spontaneous
action subsides, add 10 ec. of concentrated nitric acid. After two or three additions
of concentrated nitric acid the action becomes less violent. Heat gently, at first,
continuing the addition of concentrated nitric acid and increasing the temperature as
the digestion proceeds until the contents of the flask is straw colored or colorless
after nitric acid fumes have been boiled off. This digestion may be accomplished in
the case of albumin in 40 minutes and in the case of yolks or whole eggs in 1 hour. To
the warm liquid add 100 ce. of water; pour into a 400 ce. beaker and rinse the flask
with two successive 50 cc. portions of water. To the combined water solution add
concentrated ammonium hydroxide until faintly alkaline. Pass hydrogen sulfide gas
through the solution for 15 minutes which should be sufficient to saturate. (At this
1921] LOURIE: REPORT ON EGGS AND EGG PRODUCTS 193
point the majority of albumins indicate the presence or absence of zinc. In the case
of albumin, if zinc is present, add 1 cc. of a diluted solution of ferric chloride contain-
ing 0.5 gram of solid ferric chloride per 100 cc. This will assist in retaining zinc sulfide
on the paper when filtering. Pass hydrogen sulfide gas through the solution for 15
minutes.) Heat the beaker on a steam bath for 30 minutes; remove; and allow to
settle for 5-10 minutes. Then decant through a 9 cm. filter paper, allowing as much
of the precipitate as possible to drain thoroughly. Dissolve the zinc sulfide from this
precipitate with 10% hydrochloric acid, the solution after passing through the filter
paper being returned to the original beaker. Copper and lead sulfides are insoluble
at this point, and may be determined by the usual methods. To the hydrochloric
acid solution add 5 grams of ammonium chloride, an excess of bromine water and a
slight excess of concentrated ammonium hydroxide. Neutralize carefully with 10%
hydrochloric acid adding 2 cc. in excess; add 10 cc. of 50% by weight of ammonium
acetate and 8-10 drops of 10% ferric chloride solution, or enough to give a distinct
reddish tinge. Dilute to about 300 cc. with water and boil for 1 minute. Allow to
settle, filter while hot and wash with hot 5% ammonium acetate. Pass hydrogen
sulfide gas through the filtrate for 15 minutes. Heat for 30 minutes on a steam bath;
filter through a weighed, heavily padded Gooch crucible, using gentle suction. Wash
with hot 5% ammonium acetate solution. Dry in oven; then ignite, roasting first.
The increased weight of the Gooch crucible is due to oxide of zinc. This, multiplied
by 0.8034, gives the amount of zinc present in a 25-gram sample.
An idea of the accuracy of this method may be gained by the follow-
ing work performed by H. B. Mead. A sample of albumin was analyzed
and found to have a blank of 1.3 mg. of zinc oxide.
The following determinations were made after adding definite amounts
of zinc oxide:
TABLE 1.
Determination of zinc oxide in albumin.
ZINC OXIDE ADDED ZINC FOUND (AS ZINC OXIDE) AFTER AVERAGE
SUBTRACTION OF BLANK
gram gram gram
0.0019 0.0032 0.0028
0.0025
0.0040 0.0052 0.0047
0.0042
0.0205 0.0206 2 0.0202
0.0198
0.0410 0.0416 0.0412
0.0408
This method is an improvement over the one originally used at the
New York Food and Drug Inspection Station because it allows the
rapid handling of a large number of samples. For example, it is com-
paratively easy to run at least 12 determinations for zinc within 24
hours, whereas with the old method at least 3 days were necessary.
194 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Since the campaign inaugurated by the Bureau of Chemistry to pre-
vent the importation of dried eggs containing large amounts of zinc,
such a revolution has been caused in the methods used in China for
the manufacture of this product that there is practically no dried egg
product being offered for entry in this country which contains excessive
amounts of zinc, the Chinese now largely using aluminium plates for
the drying of the eggs.
McGeorge Method for Determinaiion of Zinc in Dried Egg Products.
Weigh 25 grams of the sample into an 11 cm. silica dish. Add 5-10 cc. of olive or
other vegetable oil and 5 cc. of a saturated solution of sodium carbonate, cover with
two 9 cm. filter papers and heat over an asbestos gauze to preliminary ashing. Trans-
fer to a muffle furnace and heat at low redness until the ash is white or nearly so.
(Albumin is likely to swell badly in the muffle, according to the stage to which the
preliminary ashing is carried.)
Cool the dish and contents, add 50 cc. of water, 10 cc. of concentrated ammonium
hydroxide and 10 cc. of a saturated solution of ammonium carbonate. Heat to boiling
and filter. (In cases where an excessive amount of zinc is present it is necessary to
heat the residue insoluble in ammonium hydroxide and treat again as above to dissolve
all of the zinc.) Acidify the combined filtrates with acetic acid, boil to remove the
excess carbon dioxide and pass hydrogen sulfide through to complete precipitation
of zinc. Filter on a tared Gooch crucible, ignite and weigh as zinc oxide.
The method devised by W. T. McGeorge for the determination of
zinc in dried egg products has been found to be very accurate by the
San Francisco Food and Drug Inspection Station. McGeorge obtained
the following results using the association method and the McGeorge
method:
TABLE 2.
Comparison of zinc determinations in dried egg products.
DESCRIPTION OF SAMPLE MC GEORGE METHOD |ASSOCIATION* METHOD
gram gram
Egg yolk (25 grams) containing no added zinc. . 0.0031 0.0034
Same egg yolk after the addition of known weights 0.0238 t
of zinc oxide before ashing.................. 0.0298}
Sample of egg albumin of high zinc content refused
NUL fAt SAN EANCISCO siti yesirstitelots tsi sis 0.0585 0.0694
*Assoc. Official Agr. Chemists, Methods, 2nd ed., 1920, 151 (except that sample was ashed at dull red-
ness and taken up in hydrochloric acid instead of destroying by acid digestion).
+ Zine oxide added, 0.0203 gram; present, 0.0031 gram; total present, 0.0234 gram.
t Zine oxide added, 0.0269 gram; present, 0.0031 gram; total present, 0.0300 gram.
All of the above determinations were made on 25-gram portions.
RECOMMENDATIONS.
It is recommended that next year corroborative studies be made of
the McGeorge method.
1921] LOURIE: REPORT ON EGGS AND EGG PRODUCTS 195
The referee was instructed to study the methods for the detection of
decomposition in dried eggs. It is recommended that no time be spent
in studying such methods unless such work can be performed at the
place where the dried eggs are actually manufactured. It is obvious
that any results obtained on dried eggs which had been shipped from
China to this country would be useless unless they could be corrolated
with results obtained on the eggs during the period of manufacture and
under manufacturing conditions. It is a well-known fact that it is a
common occurrence at Chinese factories to add ammonia to the eggs
while they are being dried. Previous to the change in the process of
manufacture which has been caused by the Bureau of Chemistry action
against egg products high in zinc, it was also a common practice to add
zinc chloride as a preservative while the eggs were being dried.
Committee C requested your referee to prepare a set of methods
covering the usual determinations made in the analysis of eggs and
egg products. Since the meeting of the association in 1919, a bulletin
has been published! which gives the results of a large number of deter-
minations of eggs of various compositions, analyzed at various sections
of the country under varying laboratory conditions. The results, in
general, show that whether eggs are examined in Washington, Phila-
delphia, New York, Chicago or San Francisco, the analytical results
agree very closely, and that, when carefully followed, the analytical
methods described in that bulletin will give concordant results in the
hands of a number of analysts. The bulletin gives a full description of
the methods used, as well as the directions, and it is recommended that
the referee for the coming year present to the association a tentative
set of methods for the analysis of eggs and egg products, based on those
used in this report.
It is recommended that a study be made to determine the preserva-
tive best suited to be used in frozen eggs which are offered for analysis
in routine regulatory work. It has been the experience at the New
York Food and Drug Inspection Station that frozen eggs which have
been melted undergo very rapid fermentation. A suitable preservative,
which could be added immediately to the samples, would make the
handling of this material much easier for the analyst and would insure
more accurate results. Toluol has been used as a preservative at the
writer’s laboratory with very unsatisfactory results, as it has been
found that a sample of frozen eggs preserved with a layer of toluol
decomposes very rapidly. It is, of course, impossible to use formalde-
hyde because of the formation of compounds with ammonia. It is
believed that chloroform or sodium fluoride will make the best pre-
servative for material of this type.
No report on food preservatives was made by the referee,
1U_S.Dept. Agr. Bull. 846: (1920).
196 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
REPORT ON COLORING MATTERS IN FOODS:
By W. E. MatHewson (Bureau of Chemistry, Washington, D.C.), Referee.
No methods for the analysis of commercial food colors have yet been
considered by the association. While food colors are used in relatively
small quantities, they are particularly likely to contain objectionable
impurities because of the methods used for their manufacture and the
lack of knowledge concerning them on the part of the public—a fact
that led to the establishment of the certification procedure by the Depart-
ment of Agriculture some twelve years ago. The following report has
been prepared to bring this matter before the association and to provide
a draft to aid in the selection of a set of official methods for the analysis -
of such products.
The methods given in this report are for the most part those used or
developed in the New York Food and Drug Inspection Station in 1908
to 1910. These methods have been slightly modified or elaborated in
many cases but when such changes give a distinctive form to the pro-
cedure the original method has also been described. A few statements
and tests in the bulletin have been omitted.
The methods for the estimation of arsenic were later much improved
by C. R. Smith by the use of potassium iodide and stannous chloride
for the reduction of pentavalent arsenic and the sensitization of the
zinc. It is understood that the arsenic method with these improve-
ments is being recommended for adoption by the association so it is
not described in this report.
All methods for the estimation of arsenic after treatment with nitric
acid have been written so that troublesome filtrations are partly avoided
by the use of aliquot portions.
Among volumetric reduction methods for the direct estimation of
coal tar dyes that of Knecht and Hibbert, depending upon the use of
titanium trichloride, has probably been given the most thorough study
by analysts. It has been used by the referee for many years with the
food colors and considered very useful. The monograph by Knecht
and Hibbert although showing the method to be a general one does
not describe experiments with any of the food colors except Naphthol
Yellow S; and the concentrations of the standard solutions they employ
are about 0.3 to 0.4 N. Solutions 0.100 to 0.103 N are much more
convenient in routine work and for these reasons it has been thought
best to give a rather complete description of the method, presenting it
1 Abstract.
2 U.S. Bur. Chem. Bull. 147: (1912). Other publications that have been of special value in preparing
the description of the methods are: Allen’s Commercial Organic Analysis. 4th ed., 1911, 5; Ludwig
Gattermann. The Practical Methods of Organic Chemistry. Translated by W. B. Schober and V. B.
Babasinian. 3rd American from the 11th German ed., 1916; and A. EB. Leach. Food Inspection and Analy-
sis. Revised and Enlarged by A. L. Winton. 4th ed., 1920.
1921) MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 197
in the form considered most suitable for food-color analysis. Not the
least of the practical advantages of the titanium trichloride method is
its applicability to the rapid determination of iron, copper, and other
common substances.
The results obtained by different analysts in determining dyes by
colorimetric comparison seem to vary a good deal in reliability and
accuracy. On this account the methods have been placed under three
headings so that those involving the use of a specially suitable light
might be more readily specified.
Ordinary colorimetric measurements in white light are particularly
unsatisfactory with yellow solutions which ordinarily show marked
absorption only in the deep blue and violet regions of the spectrum.
Small differences existing between the absorptive power of two such
solutions are difficult to perceive because the emergent residual violet
light is diluted with the red, green, yellow and light blue rays of much
greater visibility which are transmitted without loss by both solutions.
If the solutions are rather concentrated the comparison becomes still
more uncertain for, in this case, the absorption is nearly complete in
the violet and such difference as may be observed comes essentially
from an extremely narrow region at the edge of the absorption band.
This difference may be quite obscured by the presence of a trace of a
more reddish coloring matter so that colorimetric comparison of such
concentrated solutions gives results of no practical value. Obviously,
difficulties of this sort are largely avoided if the comparison is made in
violet light. The mercury arc with screens selected to absorb all of
the strong radiation except that of wave length 0.436, gives a light
particularly suitable for this work.
Spectrophotometric methods might be described or discussed more
fully but many types of apparatus are in use, each requiring its own
form of procedure. The spectrophotometer because of its convenience
and wide applicability can scarcely fail to come into more general use
in analysis. A new form of the instrument of simple construction has
recently been devised by I. G. Priest! for use with dye solutions, oils
and similiar liquids. The transmissive indices (extinction coefficients)
as well as the transmissions are read directly without computation.
A special advantage of the design lies in the fact that the illumination
of the field can be adjusted directly to the intensity best suited to the
eye so that all of the (homogeneous) light may be utilized.
For accurate colorimetric and spectrophotometric work, sources of
strong monochromatic light are of great importance. The mercury arc
with suitable screens gives fairly homogeneous radiation of the
respective wave lengths 0.436y, 0.546, and 0.577—-0.579x.
1 Colton Oil Press, July, 1920, 4: 96.
198 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
[Vol. V, No. 2
The methods have been given in the following order:
Moisture.
Total matter insoluble in water.
Inorganic or non-volatile matter insoluble
in water.
Total matter soluble in water.
Matter insoluble in carbon tetrachloride.
Sodium chloride.
Sodium sulfate.
Sulfated ash.
Heavy metals.
Calcium.
Arsenic by direct precipitation.
Arsenic after treatment with nitric acid.
Total arsenic.
Sulfur.
Nitrogen.
Total halogens.
Total iodine.
Sodium iodide.
Ether extractives.
Dye by titration with titanium trichloride,
Dye by titration with potassium per-
manganate.
Dye by colorimetric comparison.
Dye by spectrophotometer.
Lower sulfonated dyes.
Melting point.
Martius Yellow in Naphthol Yellow S.
Boiling point of Cumidine from Pon-
ceau oR.
Orange I] in Orange I.
Todeosine G in Erythrosine.
Jsomeric and similar dyes in Amaranth.
Sodium chloride in dyes or mixtures con-
taining more than 25 per cent of this
substance.
Sucrose in dye mixtures.
Sodium carbonate in Erythrosine.
METHODS FOR THE ANALYSIS OF COAL TAR FOOD COLORS.
MOISTURE.
(a) (Applicable with Ponceau 3R, Orange I, Tartrazine, Amaranth, Light Green
S. F. Yellowish, Erythrosine and Indigo Disulfoacid.)
Heat 2 grams of the finely ground dye at 135°C. in a current of hydrogen until con-
stant weight is attained.
(b) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange 1, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine and Indigo Disulfoacid.)
Dry 2 grams of the finely ground dye at 135°C. in an air oven to constant weight.
The moisture is usually driven off in from 2-4 hours.
(C) (Applicable with Yellow A. B. and Yellow O. B.)
Dry 2 grams of the finely ground dye at room temperature in a desiccator containing
sulfuric acid until constant weight is attained.
(d) (Applicable with Yellow A. B. and Yellow O. B.)
Dry 2 grams of the powdered dye in an air oven or vacuum oven at 80°C. to constant
weight.
TOTAL MATTER INSOLUBLE IN WATER.
(a) (Applicable with Naphthol Yellow S, Tartrazine, Amaranth, Light Green S. F.
Yellowish and Erythrosine.)
Dissolve 5 grams of dye in 200 cc. of hot water, filter on a Gooch crucible, wash until
the washings are colorless, dry at 100-105°C. and weigh.
(b) (Applicable with Ponceau 3R, Orange I, and Indigo Disulfoacid.)
Stir 5 grams of the dye with 250 cc. of hot water, heat the mixture to boiling and
boil for 3 minutes with occasional stirring. Filter on a tared 25 cc. Gooch crucible,
wash, dry and weigh as stated under (a). With low-grade dyes the filter sometimes
becomes clogged. In such a case the determination must be repeated, using a smaller
charge, but when this is done the weight of the charge taken must always be stated.
al
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 199
INORGANIC OR NON-VOLATILE MATTER INSOLUBLE IN WATER.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Erythrosine, Light Green S. F. Yellowish and Indigo Disulfoacid.)
Ignite the Gooch crucible containing the total insoluble matter at alow red heat
until organic matter is incinerated completely, cool and weigh.
TOTAL MATTER SOLUBLE IN WATER.
(a) (Applicable with Yellow A. B. and Yellow O. B.)
Transfer 5 grams of the well-powdered dye to a 500 cc. Erlenmeyer flask or wide-
mouthed bottle, add 200 cc. of water, stopper and mix thoroughly by shaking. Allow
to stand 2 hours with occasional shaking, filter, and evaporate 100 cc. of the filtrate in
a tared platinum dish. Dry at 100-105°C. and weigh. Test small portions of the
filtrate for chlorides, sulfates, nitrates, etc. If more than traces of these are present,
determine them in aliquot portions of the filtrate by the usual methods.
MATTER INSOLUBLE IN CARBON TETRACHLORIDE.
(a) (Applicable with Yellow A. B. and Yellow O. B.)
Mix 5 grams of the dye in a 100 cc. beaker with 50 cc. of carbon tetrachloride, stir
and heat to boiling. Filter the hot solution on a tared Gooch crucible, transfer the
residue in the beaker to the filter and complete the washing with an additional 50 cc.
of carbon tetrachloride used in portions of 5-10 cc. each. Dry at 100-105°C. and
weigh.
SODIUM CHLORIDE.
(a) (Applicable with Ponceau 3R, Orange I, Tartrazine, Amaranth, Light Green
S. F. Yellowish, and Indigo Disulfoacid.)
Mix 5 grams of dye thoroughly with 4-6 grams of potassium carbonate or sodium
carbonate in a 50 cc. platinum dish, moisten with water or 50% alcohol, cover evenly
with about 1 gram of the powdered carbonate, dry, and ignite at a low red heat until
organic matter is destroyed. Allow to cool, add enough water to form a thin paste
and if the mass does not disintegrate as the soluble salts dissolve, break up the lumps
with a glass rod. The charred mass should soften under the action of the water so
that very little stirring is necessary to produce a uniform suspension. Wash or transfer
the mixture into a 250 cc. graduated flask with 100-150 cc. of hot water and add an
excess of potassium permanganate to oxidize sulfides. Destroy the excess of permanga-
nate by adding sulfur dioxide solution until the red color changes to brown, then cool
the mixture and make up to the mark with water. Filter through a dry paper, acidify
100 ce. of the filtrate with nitric acid and precipitate the chlorine by adding a slight
excess of silver nitrate. Heat with stirring until the silver chloride has coagulated,
cool, then filter on a tared Gooch crucible and finally dry amd weigh the silver chloride
in the usual manner. [If the solution should be brown and the silver chloride tend to
pass through the filter the charge has not been completely charred and the determina-
tion must be repeated.
(b) (Applicable with Ponceau 3R, Tartrazine, Orange I, Amaranth, Light Green
S. F. Yellowish and Indigo Disulfoacid.)
Proceed exactly as described in (€) to the point at which the suspension of the dis-
integrated charred mass is obtained in a 250 cc. graduated flask, allow to stand until
all soluble salts are dissolved, cool, dilute to the mark with water, mix thoroughly and
filter through a dry paper. Measure an aliquot portion of 200 cc. of the filtrate into a
600 cc. beaker and add a sufficient amount of 6-7% solution of potassium permanga-
nate to oxidize the sulfides and produce a permanent pink color. Then add about
200 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
50 cc. of water and a slight excess of silver nitrate solution. Six to eight cc. of 10%
silver nitrate solution are usually suflicient to precipitate the chlorine. Partially cover
the beaker with a watch glass and acidify by carefully adding about 12 cc. of con-
centrated nitric acid (sp. gr. 1.42). Heat nearly to boiling, then add 1-2% sulfur
dioxide solution slowly, with stirring, until the oxides of manganese dissolve leaving
the white silver chloride. Boil until any excess of sulfur dioxide is removed, cool and
finally filter, wash and weigh the silver chloride in the usual manner.
(c) (Applicable with Naphthol Yellow S.)
Dissolve 5 grams of dye in 250 cc. of water, filter if necessary, add 5 cc. of concen-
trated nitric acid and precipitate the chlorine by adding a slight exces of silver nitrate.
The silver chloride is separated, washed, ignited and weighed on a tared Gooch crucible
in the usual way. The determination may be made conveniently in connection with
that of insoluble matter.
(d) (Applicable with Ponceau 3R.)
Dissolve 5 grams of the dye in 150 cc. of hot water, wash into a 250 cc. graduated
flask and add 25 cc. of a 10% solution of barium nitrate. Cool the mixture, make up
to the mark, mix, and filter through a dry paper; acidify 100 cc. of the filtrate, repre-
senting 2 grams of color, with nitric acid and treat with a slight excess of silver nitrate.
The precipitated silver chloride is separated, washed, ignited and weighed in a tared
Gooch crucible in the usual way.
(e) (Applicable with Erythrosine.)
Dissolve 5 grams of the dye in 400 cc. of water and add a mixture of 2 cc. of con-
centrated nitric acid with 10-20 cc. of water, then dilute the mixture to 500 cc., mix,
and filter through a dry filter. Reserve an aliquot portion of the filtrate for the estima-
tion of sulfates. Treat 200 cc. of the filtrate with slightly more silver nitrate solution
than is required to precipitate the halogens present, add 5 cc. of concentrated nitric
acid, heat to boiling, cool and filter the precipitate on a weighed Gooch crucible; dry,
cool and weigh. Test a small portion of the filtrate from the color acid by adding a
few drops of sulfuric acid, a drop of sodium nitrite solution, and a few drops of carbon
tetrachloride or starch paste. If an appreciable amount of iodide is present it must
be determined as stated under sodium iodide (€), and correction made by subtracting,
from the weight of the precipitate, the weight of silver iodide obtained in the sodium
iodide estimation. The difference is then calculated to sodium chloride.
SODIUM SULFATE.
(a) (Applicable with Light Green S. F. Yellowish.)
Dissolve 2 grams of dye in 50 cc. of hot water, filter on a small paper and wash the
residue and filter with hot water. Dilute the combined filtrate and washings to about
200 cc., add 4 cc. of concentrated hydrochloric acid, heat to boiling and add a slight
excess of 10% barium chloride solution. Allow the mixture to stand overnight, filter
on a weighed Gooch crucible, wash, ignite and weigh in the usual manner.
(b) (Applicable with Erythrosine.)
Employ an aliquot portion of not less than 100 ce. of the filtrate obtained after pre-
cipitating the color acid as described under the determination of sodium chloride, (€).
Precipitate as barium sulfate, making the determination in the usual way.
(Cc) (Applicable with Amaranth and Tartrazine.)
Introduce 5 grams of the dye into a 250 cc. graduated, stoppered flask and dissolve
in 200 cc. of warm water. Add 70 grams of pure pulverized sodium chloride, stopper
the flask and shake or stir the mixture gently at frequent intervals for 1 hour. The
salt will dissolve and ordinarily the appearance of the mixture will show that the dye
has been almost completely precipitated. In warm weather or with impure dyes the
super-saturated solution first formed will be more stable and it may be necessary to
~s
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 201
cool the mixture by placing the flask in cold water. Dilute the mixture containing the
precipitated dye to 250 cc. with a saturated solution of sodium chloride, mix, and
filter on a dry, 18 cm. filter paper. Dilute 100 cc. of the filtrate with 200 cc. of water,
add 0.1 cc. of concentrated hydrochloric acid, heat to boiling and precipitate the sul-
fates with slight excess of barium chloride solution. Allow the mixture to stand for
several hours or overnight, filter off the barium sulfate on a tared Gooch crucible, wash,
ignite and weigh in the usual manner.
(d) (Applicable with Amaranth and Tartrazine.)
Dissolve 2 grams of dye in 100 cc. of warm water in a 200 ce. graduated flask and
add 36 grams of pure sodium chloride. Allow the mixture to stand with frequent
‘shaking for 1 hour and after cooling make up to the mark with a saturated salt solution.
Shake the mixture, then filter through a dry paper; dilute 100 cc. of the filtrate (rep-
resenting 1 gram) with water, acidify with 0.1 cc. of concentrated hydrochloric acid
and precipitate the sulfates with barium chloride. The precipitate is separated,
washed and ignited on a tared Gooch crucible.
(e) (Applicable for Ponceau 3R, Orange I and Indigo Disulfoacid.)
Proceed as described under (C) using, however, a 50-gram portion of pulverized
sodium chloride instead of the 70-gram portion.
(f) (Applicable with Naphthol Yellow S.)
Dissolve 2} grams of dye with about 300 cc. of water in a 500 cc. graduated flask,
add 100 ce. of a 20% solution of potassium chloride, shake the mixture well and dilute
to 500 cc. with water. Shake again, then filter through a dry paper. Treat an aliquot
portion of the filtrate, representing not less than 1 gram of the dye, with 5 cc. of 10%
barium chloride solution and allow to stand overnight. If a precipitate forms it is
washed, dried and weighed in the usual manner.
SULFATED ASH.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine, and Indigo Disulfoacid.)
Weigh accurately 2 grams of dye in a tared platinum basin of about 100 ce. capacity,
moisten with a little dilute sulfuric acid (15-20%) and rotate the dish to spread the
pasty mixtme over the bottom. Warm over a ring burner or similar device, gently
at first to avoid spattering, finally at a somewhat higher temperature to carbonize the
mass and volatilize the sulfuric acid. Moisten the residue with concentrated sulfuric
acid and ignite, beginning at a low temperature and gradually increasing the heat to
low redness; repeat the treatment with acid and ignition until all carbonaceous matter
is removed and a white or reddish ash is obtained. Heat this cautiously over the
blast lamp until it fuses to a clear. limpid liquid and the effervescence, due to the de-
composition of the sodium acid sulfate, has just ceased, then allow to cool in a desic-
cator and weigh.
(b) (Applicable with Yellow A. B. and Yellow O. B.)
Heat 2 grams of the dye in a tared platinum dish or crucible at a low temperature
until almost all of the ccloring matter has volatilized; moisten the residue with con-
centrated sulfuric acid and heat cautiously at first, then to low redness, to burn off all
carbonaceous matter. If the residue incinerates with difficulty it will be necessary to
repeat the treatment with sulfuric acid and subsequent ignition several times. When
carbonaceous matter is completely destroyed, ignite over the blast lamp, cool and
weigh.
-
HEAVY METALS.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange 1, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erytbrosine, and Indigo Disulfoacid.)
202 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Moisten the sulfated ash with a few cc. of concentrated hydrochloric acid and evap-
orate to dryness on the steam bath. Warm the residue with a mixture of 1 cc. of con-
centiated hydrochloric acid and about 20 cc. of water until all soluble material has
been dissolved; transfer to a 100 cc. graduated flask or cylinder, dilute with water to
100 cc., mix and pour on a dry filter. Reserve 50 cc. of the filtrate for the estimation
of calcium. Place 10 cc. of the filtrate in a test tube, add 10 cc. of freshly prepared
hydrogen sulfide test solution (U.S. P.), shake the mixture, warm to 50°C., stopper
and allow to stand in a warm place (about 35°C.) for 30 minutes. Run a blank test
at the same time with the same amount of hydrogen sulfide solution, using water
instead of the solution containing the asb. No turbidity other than that produced by
a slight separation of sulfur should appear in this test. Both tubes are then made
slightly alkaline with ammonium hydroxide and no precipitate should be produced,
although a slight coloration, due to the presence of a small amount of iron, sometimes
occurs. If this coloration is very marked, the amount of iron should be determined.
This is done by digesting the sulfated ash from a weighed amount of the sample with
hydrochloric acid until all the iron has gone into solution. Filter the liquid and pour
the filtrate into an excess of hot, pure, freshly prepared sodium hydroxide solution in
a platinum dish. Wash the precipitate, dissolve in dilute hydrochloric acid and again
precipitate with ammonium hydroxide. Wash the last precipitate, ignite and weigh
in the usual manner.
(b) (Applicable with Yellow A. B. and Yellow O. B.)
If the residue from the sulfated ash consists mainly of iron oxide, silica, or similar
insoluble compounds, fuse it in the dish with about 1 gram of potassium carbonate or
sodium carbonate until any silicates have been decomposed. Moisten the residue
with 2-3 cc. of concentrated hydrochloric acid, evaporate to dryness on the steam
bath and continue as directed under (a). The preliminary fusion with alkaline car-
bonate may he omitted if the ash consists chiefly of sodium sulfate.
CALCIUM.
(a) (Applicable with Naphthol Yellow 8, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine, Indigo Disulfoacid, Yellow A. B. and
Yellow O. B.)
The aliquot portion of the solution reserved for the estimation of the calcium, as
directed under the determination of heavy metals, (€), represents the sulfated ash
from 1 gram of dye. Heat the solution to boiling, add a slight excess of ammonium
hydroxide solution, boil a few minutes and filter off any ferric hydroxide that may be
precipitated, on a small paper filter. Wash the filter paper and residue with a little
water, collecting the washings in the same beaker with the filtrate. Heat the solution
to boiling, precipitate the calcium with a slight excess of ammonium oxalate and filter
on a tared Gooch crucible. Wash the precipitate, dry at 100°C. and weigh as
CaC,0,.H,0. If preferred, the precipitate may be filtered on a Gooch crucible not
previously tared, the asbestos and calcium oxalate rinsed into a beaker with about
100 ce. of water, 2 cc. of concentrated sulfuric acid added and the solution warmed and
titrated against O.1 N potassium permanganate solution in the usual manner.
ARSENIC BY DIRECT PRECIPITATION.
(a) (Applicable with Naphthol Yellow S, Tartrazine, Amaranth, and Light Green
S. F. Yellowish.)
Dissolve 10 grams of the dye in 250 cc. of water and add 10 cc. of strong bromine
water. Make the mixture alkaline with 1-2 cc. of concentrated ammonium hydroxide
solution, then add 20 cc. of a sodium phosphate solution containing 100 grams of the
crystallized salt per liter. Finally add a slight excess of magnesia mixture (containing
{
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 203
55 grams of hydrated magnesium chloride, 55 grams of ammonium chloride and 88 cc.
of ammonium hydroxide solution, sp. gr. 0.90, per liter). The amount of magnesia
mixture used must be 1-5 cc. in excess of that required to completely precipitate the
phosphate, as ascertained previously by experiment, and it must be poured into the
dye mixture slowly, the latter being well stirred during the addition. Add 10 cc. of
ammonium hydroxide (sp. gr. 0.90) and allow the mixture to stand for at least 30 min-
utes. Filter on an 18 cm. paper filter and wash with water containing one-tenth its
volume of concentrated ammonia solution until practically all of the dye is removed.
Wash with about 5 cc. of water, allow the filter containing the washed precipitate to
drain 15-30 minutes to remove most of the adhering liquid. Finally dissolve the
magnesium ammonium phosphate and arsenate by pouring several small portions of
10% hydrochloric acid over the filter. Dilute the total filtrate to 40 cc. with 10%
hydrochloric acid and determine arsenic!, the hydrochloric acid solution being sub-
stituted for the sulfuric acid mixture?. The hydrochloric acid solution is treated with
potassium iodide, this and subsequent operations being carried out exactly as specified’,
It is well to make the standard stains by treating 250 cc. portions of water with known
amounts of a standard sodium arsenate solution, precipitating the arsenic as stated
for the dye solution and carrying out the further analytical operations in exactly the
same way.
(b) (Applicable with Erythrosine.)
Dissolve 18 grams of dye in 425 cc. of water, add 5 cc. of strong bromine water and
20 cc. of 10% hydrochloric acid. Mix, filter and treat 250 cc. of the filtrate (corre-
sponding to 10 grams of dye) with 5 cc. of concentrated ammonium hydroxide solution
(or a sufficient amount to render it slightly alkaline). Precipitate and determine the
arsenic by the addition of sodium phosphate and further operations as described
under (a).
ARSENIC AFTER TREATMENT WITH NITRIC ACID.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine, and Indigo Disulfoacid).
Place 12.5 grams of the powdered dye in a 600 cc. beaker of Pyrex or similar resistant
glass, add 25 cc. of concentrated nitric acid and, in case the dye tends to form a clot or
cake, stir the mixture thoroughly. Heat to boiling, keep at boiling temperature for about
5 minutes, then add 150-200 cc. of water, pour into a graduated 250 cc. cylinder and
dilute the mixture to 250 cc. Mix by pouring back into the beaker, and allow to stand
for a few minutes, then filter on an 18 cm. paper filter. Treat 200 cc. of the filtrate,
corresponding to 10 grams of dye, with 25 cc. of strong ammonium hydroxide solution
(or a sufficient measured amount to make the solution alkaline). Finally precipitate
and determine the arsenic by the addition of sodium phosphate solution and further
operations as described under the determination of Arsenic by Direct Precipitation,
(a), correcting for any traces of arsenic in the reagents by blank fests or standard stains
obtained with the same amounts of the reagents.
(b) (Applicable with Yellow A. B., and Yellow O. B.)
Mix thoroughly 15 grams of the powdered dye in a 400 cc. beaker with 150 cc. of
10% nitric acid, heat to boiling, allow to cool, neutralize with ammonium hydroxide
and measure the liquid in a graduated cylinder. Filter and determine the arsenic in
an aliquot portion of the filtrate corresponding to 10 grams of dye by precipitation
with magnesia mixture and subsequent operations as described under Arsenic by
Direct Precipitation, (a).
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 147.
2 Tbid., 148, 4.
3 Tbid., 149.
204 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TOTAL ARSENIC.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine, Indigo Disulfoacid, Yellow A. B. and
Yellow O. B.)
Digest 10 grams of the dye with a mixture of measured amounts of concentrated
sulfuric acid and nitric acid until all organic matter is destroyed. It is recommended
that the dye be introduced into a tall 600 cc. beaker of refractory glass provided with
a watch glass cover, or into a 600 cc. Kjeldahl flask. Treat with 15 cc. of concentrated
sulfuric acid, then add 25 cc. of concentrated nitric acid and digest slowly under a
hood until the nitric acid has been decomposed or volatilized and the mixture begins
to turn dark. Add cautiously a few cc. of nitric acid to the hot mixture which will
again become light yellow or orange and repeat the addition of small quantities of
nitric acid at intervals until the solution no longer shows a tendency to darken on
further heating. The nitric acid must be taken from a previously measured portion
of about 50 ce. or be added otherwise in such a manner that the total quantity used
will be known. Allow the completely digested mixture to cool and add 200 cc. of
water, then treat with concentrated ammonium hydroxide solution from a graduated
cylinder until the mixture becomes slightly alkaline (corresponding to an excess of
1-3 cc.) and note the total amount added. Determine the arsenic in the solution by
precipitation with phosphate solution and magnesia mixture and subsequent opera-
tions as described under Arsenic by Direct Precipitation, (a). The comparatively
large amounts of reagents necessary for the destruction of the organic matter will
usually contain appreciable quantities of arsenic for which correction must be made
by blank determination. Measure into a roughly tared 600 cc. beaker quantities of
the sulfuric and nitric acids equal to those used in the digestion. Heat under the
hood until the sulfuric acid begins to volatilize, then allow to cool and weigh the beaker
again on scales accurate to 1 or 2 grams. Calculate the approximate amount of acid
(as sulfuric acid) in the original digestion mixture, after complete destruction of the
dye, from the number of cc. of concentrated ammonium hydroxide solution that was
required to neutralize it, and evaporate the mixture of acids measured off for the blank
until the quantity remaining is nearly the same as that of the original mixture after
digestion. Allow to cool and carry out the subsequent procedure as with the residue
obtained by destruction of the dye. If the amount of arsenic found in the blank
determination exceeds 0.000005 gram of arsenious oxide (corresponding to 0.5 parts
per million with a 10-gram charge of dye) the correction to be made will be quite inac-
curate and purer reagents should be secured for the work.
SULFUR.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish, Erythrosine, and Indigo Disulfoacid.)
Determine upon 0.2-0.3 gram portions by the Carius method, using 3 ce. portions
of fuming nitric acid and heating the sealed tubes to 300°C. for at least 8 hours.
NITROGEN.
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine,
Amaranth, Light Green S. F. Yellowish, Indigo Disulfoacid, Yellow A. B. and Yellow
O. B.)
Use the method of Dumas.
(b) (Applicable with Light Green S. F. Yellowish, and Indigo Disulfoacid.)
Determine on 2-gram portions by Gunning’s modification of the Kjeldahl process,
using a little copper sulfate to assist the oxidation.
(c) (Applicable with Ponceau 3R, Orange I, Tartrazine and Amaranth.)
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 205
Treat 2 grams of the color with 25 ce. of a saturated solution of sulfur dioxide and
1 gram of zinc dust, and warm the mixture gently until it becomes colorless. This
should take place in 2-3 minutes, but if it does not, add more sulfur dioxide solution,
in small portions at a time, until the color is destroyed. Then add 30 ce. of concen-
trated sulfuric acid and 0.7 gram of mercuric oxide, or its equivalent of metallic mer-
cury, and digest the mixture. Finally make alkaline and distil as usual in the Kjeldahl
method.
TOTAL HALOGENS.
(a) (Applicable with Erythrosine.)
Mix 0.5-1 gram of the dye with 4 grams of potassium carbonate, moisten to a paste,
dry, coyer with a layer cf dry potassium carbonate and ignite at a low red heat. Allow
to cool, moisten with a few drops of water and break up the charred mass thoroughly.
Wash into a beaker with about 200 cc. of water, allow to digest for 15 minutes and
filter. Wash the insoluble matter until the washings no longer react with silver nitrate;
then acidify the filtrate and washings with nitric acid and precipitate the halogens
with silver nitrate. Filter, wash, and weigh the insoluble silver salts on a tared Gooch
crucible in the usual manner.
' TOTAL IODINE.
(a) (Applicable with Erythrosine.)
Place 0.3-0.4 gram of the dye in a porcelain casserole, dissolve in 5 cc. of a 10%
sodium hydroxide solution, then add 35 ce. of a 7% solution of pure potassium per-
manganate. After mixing, partially cover the vessel with a watch crystal and add
10 ce. of nitric acid. Agitate the mixture, place on a steam bath and keep covered
urtil spattering ceases, after which remove the watch glass and allow evaporation to
proceed to dryness. Care should be taken to prevent access of reducing gases or vapors
to the mixture. Treat the residue with 5 cc. of 7% potassium permanganate and
5 cc. of concentrated nitric acid and again evaporate to dryness. Then add about
50 ce. of water and 5 cc. of concentrated nitric acid to the residue, following this by
40 cc. of a saturated solution of sulfur dioxide, and allow the whole to stand with oc-
casional stirring (breaking up the lumps with a glass rod) until the hydrated oxide of
manganese has dissolved. Filter and wash the filter paper thoroughly with water,
add an excess of silver nitrate to the combined filtrate and washings and boil until
sulfur dioxide has been expelled and the silver iodide has flocculated. Separate, wash
and weigh the precipitate in the usual manner.
The solution of the oxides of manganese often requires some time, as the hardened
residue is not rapidly attacked by the sulfur dioxide solution. With dyes known to
be free from more than traces of salt or of other chlorine or bromine compounds it is
unnecessary to evaporate the acid digestion mixture to dryness; heat to boiling with
stirring to prevent bumping, allow to cool somewhat, and treat with about 50 cc. of
cold water. Then add strong sulfur dioxide, not too slowly-and while the mixture is
being well stirred, until the oxides of manganese dissolve with the formation of a clear
colorless solution. Treat the solution with a sufficient amount of silver nitrate solu-
tion to precipitate all of the iodine, heat to boiling and boil until sulfur dioxide has
been expelled. Separate the silver iodide and weigh in the usual manner.
(b) (Applicable with Erythrosine.)
Mix 0.2-0.3 gram of the sample with 2 grams of pure potassium dichromate and
15 cc. of strong sulfuric acid in the evolution flask of an apparatus made entirely of
glass with ground-glass joints. Thoroughly mix the contents of the evolution flask so
that all lumps are disintegrated, heat at 100°C. for 15 minutes, after which raise the
temperature to 150°C. for 30 minutes, a current of air, dried over calcium chloride ard
potassium hydroxide, being drawn through the apparatus during this time. Iodine
206 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
remains in the evolution flask as iodic acid; bromine passes off as such, and may be
absorbed by allowing the air passing through the apparatus to bubble through 1%
sodium hydroxide. Chlorine passes out of the evolution flask as chromyl chloride,
and may also be absorbed in sodium hydroxide. Cool the mixture containing the iodic
acid, and reduce the chromic acid by the addition of sulfur dioxide, about 20 cc. of a
saturated solution being required. When a sufficient amount has been added the
precipitated iodine redissolves, and the clear green color of chrome alum appears.
Filter, wash the paper with water, dilute the filtrate and washings to about 300 cc.,
and add an excess of silver nitrate. Boil till the silver iodide has flocculated, allow
to stand for a few hours, and separate and weigh the silver iodide in a tared Gooch
crucible.
It sometimes happens that the mixture becomes turbid after the reduction with
sulfur dioxide owing, apparently, to the separation of a basic chromium sulfate. Very
often the turbidity can not be removed by filtering and it has been found advisable in
this case to reject the determination and begin anew.
SODIUM IODIDE.
(a) (Applicable with Erythrosine.)
Dissolve 5 grams of the dye in 400 cc. of water and add a mixture of 2 cc. of con-
centrated nitric acid (sp. gr. 1.42) with 10-20 cc. of water. Dilute to exactly 500 cc.,
mix and filter on a dry paper. Place 200 cc. of the filtrate in a porcelain casserole and
make slightly alkaline with pure sodium hydroxide solution. Treat with an excess
of 7% potassium permanganate solution and conduct subsequent operations as directed
for the alkaline dye solution under Total Iodine, (a). However, when the total quan-
tity of inorganic halogen present is small it is well to use correspondingly smaller
amounts of the potassium permanganate and sulfur dioxide solutions.
ETHER EXTRACTIVES,
(a) (Applicable with Naphthol Yellow S, Ponceau 3R, Orange I, Tartrazine, Ama-
ranth, Light Green S. F. Yellowish and Indigo Disulfoacid.)
Dissolve 10 grams of color in 150 cc. of water and extract in a separatory funnel
with ether that has been washed with water (using three 150 cc. portions of water for
each liter of ether). Extract the color solution with two 100 cc. portions of this ether,
shaking thoroughly for 1 minute, and wash the combined ether extract successively
with 35, 20 and 10 cc. of water made alkaline or acid, as the case requires, with 1 ce.
of 0.1 N alkali or acid per 100 cc. of water. Decant the ether from the mouth of the
separatory funnel and rinse the latter once with 5 cc. of ether. The color solution is
first extracted neutral, the extracted solution being then rendered alkaline with 2 ce.
of a 10% solution of sodium hydroxide and again extracted with two 100 cc. portions
of ether. In acidifying for the third extraction, add twice the amount of hydrochloric
acid (1 to 8) necessary to neutralize the alkali, and repeat the extraction with two
100 cc. portions of ether. Place the neutral, alkaline, and acid extracts in a dust-free
atmosphere and allow the ether to evaporate spontaneously, after which dry the resi-
dues to constant weight over sulfuric acid, using flat-bottomed dishes 2} inches in
diameter, 1} inches in height, and of about 100 cc. capacity. The dishes should be
thoroughly cleaned, wiped dry, and allowed to stand in a sulfuric acid desiccator for
at least 2 hours before weighing. In order to avoid the generation of static charges
of electricity, they should not be wiped immediately before weighing. Run two blank
determinations with each series of ether extracts and deduct the average gain in weight
of these two blanks from the weights obtained in the other determinations.
(b) (Applicable with Erythrosine.)
Determine as given under (&) omitting, however, the acid extraction.
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 207
DYE BY TITRATION WITH TITANIUM TRICHLORIDE.
(a) (Applicable with Amaranth, Ponceau 3R, Orange I, and Tartrazine.)
Prepare a standard 0.1 N ferric iron solution from pure crystallized ferrous ammo-
nium sulfate, (NH,).Fe(SO,)..6H.O. Weigh accurately 39.22 grams of the salt,
transfer to a 1-liter graduated flask with 200-300 cc. of water and 30 cc. of pure con-
centrated sulfuric acid and agitate until the ferrous compound is dissolved. Weigh
exactly 3.16 grams of pure crystallized potassium permanganate, dissolve in 100-200 cc.
of warm water and add the solution slowly with stirring to the liquid in the flask. The
permanganate solution should be exactly sufficient to oxidize the iron but it is well
to add the last few cc. drop by drop. The iron solution, after having been treated
with sufficient permanganate to show a faint but perceptible reddish tint, is cooled
and diluted to 1 liter. ;
The standard titanium trichloride solution should be preserved in an atmosphere
of hydrogen in an apparatus similar to that illustrated in Fig. 1. The reservoir bottle
Fic. 1. APPARATUS FOR TITRATION WITH STANDARD TITANIUM TRICHLORIDE SOLUTION.
is connected by means of a syphon to the side neck of the buret. The buret is pro-
vided at the side neck tube and bottom with valves made from rather heavy red rubber
tubing (of the very best quality) and carefully fitted glass beads. Glass tubes also
connect the bottle with the top of the buret and with the Kipp hydrogen generator
and reach about 3 inch below the rubber stopper of the reservoir. The tube leading
to the top of the buret is connected with the latter by means of a tight rubber stopper.
208 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
The gas outlet tube of the Kipp apparatus is fitted with a well-greased glass stop-cock
and connected by means of rather thick-walled rubber tubing to the glass tube leading to
the bottle. The generator, which should be charged with stick zinc and dilute sulfuric
acid, may be of 1-pint or 1-quart capacity. A 25 cc. buret and 2-liter reservoir bottle
are of conyenient capacity and the whole apparatus, including the generator, may be
supported on a large, heavy ringstand by means of clamps and rings.
Prepare a dilute titanium trichloride solution by mixing 200 cc. of the commercial
15% solution with 100-200 cc. of concentrated hydrochloric acid and diluting with
water to 2 liters. Measure exactly 10 cc. of the ferric ammonium sulfate solution
into a small beaker and add a few grams of pure ammonium sulfocyanate or an equiva-
lent amount of the concentrated solution. Fill a buret or graduated pipet with the
titanium solution just prepared and add with stirring to the ferric sulfocyanate mix-
ture until the color changes from red to pale yellow or colorless. Note the number
of ce. of the trichloride used and add sufficient water or strong trichlorides as the case
may require to bring the titer to between 0.100 N and 0.103 N. Transfer the solution
to the reservoir bottle of the apparatus just described, which it must fill almost com-
pletely, insert the stopper and fittings into the bottle and wire down snugly, then fill
the buret by applying suction at the top, the valve in the side tube being held open
meanwhile. Care must be taken that all bubbles are carried out of the syphon tube.
Insert the stopper at the top of the buret loosely and carefully open the stop-cock of
the Kipp apparatus, allowing 100-200 cc. of hydrogen to pass over the solution and
carry out most of the air. Insert the stopper in the buret and wire it down if necessary
to make a tight joint. Finally open the stop-cock of the Kipp apparatus.
Before standardizing the solution it should be allowed to stand a day or so, so that
any residual oxygen may be absorbed. The stock bottle should then be tilted back
and forth a few times to eliminate any slight differences in concentration at the surface
of the liquid and, after refilling the buret, the solution is ready for standardization.
Titanium trichloride solutions rapidly take up oxygen if not kept in well-stoppered
bottles and commercial 15-20% preparations often contain rather large amounts of
titanic compounds. When such partially oxidized solutions are used a white pre-
cipitate may form in the volumetric solution on standing. Although this does not
affect the titer the precipitate may cause some inconvenience by clogging the valves.
The formation of this precipitate may be avoided by using more hydrochloric acid in
making up the solution but as this involves the use of larger amounts of sodium tartrate
in some of the titrations a very strongly acid reagent is unsatisfactory.
Standardize the titanium trichloride solution by titration against the standard iron
solution. Measure 20 cc. of the 0.1 N ferric ammonium sulfate into a 100 ce. flask,
add 10 ce. of a 50% solution of pure ammonium sulfocyanate and titrate at room
temperature in a slow current of carbon dioxide. The end point is shown by the dis-
appearance of the red ferric sulfocyanate, the liquid becoming colorless or very pale
yellow. The reduction is almost instantaneous but the last few drops of the solution
should be added rather carefully. A rubber tube ending in a glass fitting which is
hooked over the lip of the flask serves to conduct carbon dioxide from a bomb or Kipp
generator over the surface of the liquid.
It is advisable also to determine the acidity of the titanium trichloride. Measure
5 or 10 cc. from the buret, add a measured excess of normal sodium hydroxide, allow
to stand until the dark titanious hydroxide has oxidized to the white titanic compound,
then add phenolphthalein or other indicator and titrate against standard acid.
Prepare a dye solution for the titration containing such an amount of the color that
from 15-20 ce. of the standard trichloride will be required for its reduction. The
quantities of each of the pure coloring matters reacting with 20 ce. of 0.1 N titanium
trichloride may readily be ascertained from the table, page 216, and if these quantities
of the crude dyes are taken for the titration the calculations are simplified. The volume
1921| MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 209
of the portion of dye solution taken for a titration should be 10-50 cc. Acidify the
liquid by adding 1-2 cc. of concentrated hydrochloric acid, heat to boiling and boil
for a few seconds in a current of carbon dioxide. Then remove from above the burner
and, without interrupting the flow of carbon dioxide, titrate at once with the titanium
solution.
Pyrex or similar Erlenmeyer flasks of 200 cc. capacity are convenient for this work
as they may be held at the neck with forceps or a good spring hand clamp and heated
directly over the free flame. The carbon dioxide is led from the bomb or generator
through a rubber tube to a bent glass tube that hooks over the neck of the flask and
conducts the gas below the surface of the dye solution. Burner, gas generator and
titrating apparatus must be arranged within a few feet of each other.
No indicator is required in the titration as the end point is shown by the disappearence
of the characteristic color of the dye, the mixture usually becoming colorless. The
reduction takes place rather slowly in hydrochloric acid solution and, since the titanium
compound readily absorbs oxygen, inaccurate results are usually obtained if it is added
too slowly to the dye mixture. It is therefore advisable to determine the approximate
amount required by a preliminary test. The reduction is more rapid with Amaranth
than with Orange I, Ponceau 3R or Tartrazine, and the three last-named dyes can
usually be estimated better in acid tartrate solution as described under (C). In making
the dye titration the end point is easily overstepped so that it is of advantage to have
a standard dye solution to titrate back any excess of titanium trichloride added acci-
dentally or otherwise. Standard methylene blue solution is most convenient for this
purpose. Amaranth and Light Green S. F. Yellowish are more readily available and
it is recommended that standard solutions of these dyes (of 0.1 and 0.02 N respect-
ively) be kept in stock bottles provided with capped, graduated pipets passing through
the stoppers. The green will not be used for titrations in acid solution but is useful
for certain determinations specified below under (C), (€) and ($). Because of the
re-activity of the titanium trichloride, a large excess must not be added in making
the determination in an open flask, as just described. If the amount of the standard
dye solution required shows that an excess of trichloride greater than 0.3 cc. has
been added the determination must be repeated.
(b) (Applicable with Naphthol Yellow S.)
Dissolve an amount of the dye corresponding to about 20 cc. of the titanium solution
with a few cc. of water in a small flask provided with a rubber stopper and Bunsen
valve. Add a slight excess of the titanium solution, prepared as described under (a).
Pass a few hundred cc. of carbon dioxide over the surface of the liquid to displace air,
stopper the flask and heat nearly to boiling for about 5 minutes. Then pass in carbon
dioxide and titrate the excess of the reducing agent with standard methylene blue
solution, or with standard Amaranth solution at boiling temperature, as indicated
under (a). Naphthol Yellow S is more conveniently determined by titration in tar-
trate solutions, as given under (€) and (§). .
(€) (Applicable with Light Green S. F. Yellowish and Indigo Disulfoacid.)
Proceed exactly as described under (€) except that the dye solution to be titrated
is diluted to a volume of 60-75 cc. and treated with sodium acid tartrate instead of
hydrochloric acid. Care must be taken on heating the solutions to boiling as they
sometimes tend to foam at first. On this account the mixture should be cautiously
boiled for a few moments before introducing the tube from the carbon dioxide generator.
The amount of tartrate employed must be slightly greater than that required to react
with the acid in the standard titanium solution used. The number of grams of crystal-
lized sodium acid tartrate, NaC,H,O, H.O, equivalent to 20 cc. of the titanium tri-
chloride is ascertained by multiplying the figure found for the acid normality of this
solution by 3.8.
210 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
(d) (Applicable with Ponceau 3R, Orange I, Tartrazine, and Amaranth.)
Proceed exactly as described under (c). However, the solution should be standard-
ized against pure samples of the dyes in question and the values so obtained used in the
calculation instead of the values found with iron. The error introduced by using the
iron value will tend to make the results too low but will not affect the figures more
than 2% in the case of Ponceau 3R, Orange I and Tartrazine. With Amaranth the
error is greater (perhaps 5 per cent) and as this presumably is due to side reactions,
not well understood, it is advisable under ordinary circumstances to titrate this dye in
acid solution by method (a).
(e) (Applicable with Naphthol Yellow S.)
Proceed as directed under (C) adding, however, 1 cc. of 0.2 N solution of Light
Green 8. F. Yellowish to the solution to be titrated to serve as indicator. Subtract
0.20 from the buret reading to correct for the effect due to the green.
(f) (Applicable with Yellow A. B. and Yellow O. B.)
Use a solution of from 0.1-0.2 gram of dye in about 50 ce. of 95% alcohol. Weigh
off a slight excess of sodium acid tartrate, calculated as stated under (C), dissolve in
about 50 cc. of boiling water, mix the solution with the alcoholic dye solution and
titrate as directed under (d).
(§) (Applicable with Indigo Disulfoacid. Approximate values may also be ob-
tained with Light Green S. F. Yellowish, Ponceau 3R, Orange I, Tartrazine, and Ama-
ranth.)
Titrate exactly as stated under (€) and (d) using neutral sodium tartrate, however,
instead of the acid salt. The amount in grams of crystallized sodium tartrate,
Na,C,H,O, . 2H.O, equivalent to 20 cc. of the titanium solution is found by multiplying
the acid normality by 2.3. The azo dyes show the irregularity noted under (d) to a
slightly greater extent.
(h) (Applicable with Naphthol Yellow S.)
Proceed as directed under (§) adding, however, the indicator as used in (@).
(i) (Applicable with Erythrosine.)
Dissolve an amount of the product equal in weight to 2000 mol. of the pure coloring
matter (0.440 gram in case of Erythrosine) in 50 cc. of water, and add a quantity of
neutral sodium tartrate equal to that which would be required to form free tartaric
acid and sodium chloride with the hydrochloric acid in 20 cc. of the titanium trichloride.
Warm until the salt has dissolved, then add 50 cc. of alcohol, heat cautiously to boiling
in a stream of carbon dioxide and titrate in the usual way. As the reaction takes
place rather slowly and the volume of the mixture is large in comparison with that of
the trichloride required, the results ordinarily obtained are not very accurate.
General statements concerning titrations with titanium trichloride. —The procedures
just described differ mainly through the variation in the acidity or hydrogen-ion
concentration of the solutions in which the reduction is brought about. The
reduction of the azo colors in hydrochloric acid solution appears to take place
through a single reaction while at the lower acidity of the sodium tartrate and acid
tartrate mixtures this is not strictly true. However, the reduction in hydrochloric
acid takes place slowly while in the tartrate it is practically instantaneous so that in
the latter case end points can be determined much more easily. In ordinary laboratory
practice therefore the acid tartrate usually gives better results. The neutral tartrate
gives in most cases less satisfactory results than the acid salt although it may be more
suitable for dyes reduced with great difficulty. It is somewhat more convenient to
use where applicable, as it is more soluble and but little more than half as much is
required.
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 211
DYE BY TITRATION WITH POTASSIUM PERMANGANATE.
(Applicable with Indigo Disulfoacid.)
Use a solution made by dissolving 0.200 gram of dye and diluting to 400cc. Add
2 cc. of pure sulfuric acid and titrate against standard approximately 0.1 N potassium
permanganate solution, the end point being shown by the production of a clear yellow
color. As the amount of permanganate required for decolorization is some 5-10%
less than that required by theory (assuming the formation of isatin-sulfonic acid) the
titer of the standard solution must be fixed empirically by titration against indigo
disulfoacid of known purity, the same conditions of concentration and acidity being
observed.
DYE BY COLORIMETRIC COMPARISON.
(a) (Methods applicable with all coloring matters that dissolve without decompo-
sition and form stable solutions in aqueous or organic solvents.)
The graduated tubes or colorimeter employed for this examination must be so made
as to enable the ratio between the thicknesses of the layers of the two solutions com-
pared to be read within a few per cent of its value. It must also permit such adjust-
ment as is necessary to eliminate any error due to unequal illumination or to color of
the glass parts.
Prepare a solution of the coloring matter of such concentration that the predomi-
nant hue appears somewhat pale (due to admixture of white light) when viewed in a
layer of thickness within the working limits of the comparison apparatus employed.
Compare with a standard solution of known concentration in another portion of the
same solvent. Concentration of the standard solution must be adjusted by pre-
liminary trial if necessary so that it does not differ more than 20 per cent from that
of the unknown. In reporting results obtained by this method, dye concentrations,
solvent and type of apparatus should be stated.
(b) Proceed as described under (A) using, however, ordinary light modified by
passage through colored glass or ray filters, in making the colorimetric comparisons.
In general, the hue of the screen should be the complement of that of the solution.
(Cc) Proceed as directed under (€) except that the comparison is made in mono-
chromatic light and with a colorimeter such as the Dubosc type permitting fairly
accurate adjustment. The solutions must be of such concentration that they trans-
mit only sufficient light to permit accurate visual comparison of the fields of the instru-
ment and must in no case transmit more than 10% of the incident light. The light
used must be of a wave of length for which the dye shows relatively high absorption.
When results by this method are given the concentration of the solution, solvent,
thickness of layer observed and wave length of light used should be indicated.
DYE BY SPECTROPHOTOMETER.
(Methods applicable with all coloring matter that dissolve without decomposition
and form stable solutions in aqueous or organic solvents.)
(a) (With monochromatic light source.) Procedure to be followed will depend
upon kind of apparatus used. In reporting results give the extinction coefficient, with
light of specified wave length, from which the dye concentrations were calculated.
(b) (With white light source.) Report results as under (a) including also the
standard specific extinction coefficients used for comparison.
LOWER SULFONATED DYES.
(a) (Applicable with Amaranth and Tartrazine.)
Dissolve a known amount of from 0.15-0.2 gram of the dye in 50 ce. of water and
add 1 cc. of concentrated hydrochloric acid. Extract the solution by shaking out
212 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
successively in three separatory funnels each containing 50 cc. of amyl alcohol. Wash
the amyl alcohol portions by shaking with 50 ce. of 0.25 N hydrochloric acid, which is
passed in succession through the first, second and third funnels in the same way as the
original solution. Repeat this washing operation with two further portions of 0.25 N
acid. (One volume of concentrated hydrochloric acid (sp. gr. 1.20) diluted with 50
volumes of water gives an approximately 0.25 N acid.) Dilute the organic solvent
with 1-2 volumes of gasoline and remove the water-soluble dyes by washing with
several portions of water.
Estimate the separated dye by titration against standard titanium trichloride so-
lution in the presence of sodium acid tartrate; or by a colorimetric procedure. State
the procedure used for the estimation in reporting results.
(b) (Applicable with Ponceau 3R.)
Proceed exactly as described under (@) substituting, however, 50 cc. portions of
amyl alcohol-gasoline mixture for the portions of amyl alcohol. The solvent is made
by mixing equal volumes of amy! alcohol and low boiling point gasoline (sp. gr. 0.65).
(c) (Applicable with Indigo Disulfoacid.)
Carry out operations as described under (@) except that the original dye solution
is treated with 1-3 cc. of concentrated hydrochloric acid instead of 1 cc. and the wash-
ing acid is made 0.0625 N instead of 0.25 N.
(d) (Applicable with Light Green S. F. Yellowish.)
Prepare an acetate-salt mixture by treating a concentrated solution of sodium
chloride containing 125 grams of the salt with a concentrated solution of 13.6 grams of
crystallized sodium acetate NaC,H,0..3H.O, adding 12 cc. of glacial acetic acid and
diluting to 500 cc.
Dissolve 0.100 gram of the dye in 5-10 cc. of water, add 40 cc. of the salt-acetate
mixture and extract the solution by shaking out successively in three separatory fun-
nels each containing 50 cc. of amyl alcohol. Wash the amyl alcohol portions with
three 50 cc. portions of the acetate-salt mixture, shake out each portion of washing
liquid successively in the three funnels, and pass through the series in the same order
as was the original solution. Remove the dye from the solvent and estimate as given
under (a).
MELTING POINT.
(a) (Applicable with Yellow A. B. and Yellow O. B.)
Determine by the procedure described by Gattermann.
SPECIAL METHODS.
MARTIUS YELLOW IN NAPHTHOL YELLOW S.
Dissolve 5 grams of the dye in 150 cc. of water, add 5 cc. of concentrated hydrochloric
acid and shake vigorously in a separatory funnel for 1 minute with 50 cc. of petroleum
ether or low boiling point gasoline. Separate the solutions and extract the aqueous
liquid again with 25-80 ce. of the solvent. Combine the portions of gasoline, decant
into a clean separatory funnel and wash with four 25 cc. portions of 0.25 N hydro-
chloric acid. Then remove the Martius Yellow by shaking with a few portions of
dilute sodium hydroxide solution. Neutralize the alkaline dye solution with tartaric
acid, add sodium tartrate if necessary and titrate against standard titanium trichloride
as described for Naphthol Yellow S. Very small amounts may also be estimated colori-
metrically (in neutral or slightly alkaline solution) by matching against a standard
Naphthol Yellow S Solution, the tinctural power of the latter dye being considered as
eight-tenths that of Martius Yellow. (The extraction procedure described is appli-
cable with amounts of Martius Yellow below about 0.1 per cent.)
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 213
BOILING POINT OF CUMIDINE FROM PONCEAU 3R.
(a) Dissolve 60 grams of the dye in a 600-700 cc. beaker with about 450 cc. of
boiling water, add the hot solution very slowly to a warm solution of 100 grams of
stannous chloride in 100 cc. of concentrated hydrochloric acid. The dye solution
must be added 10-20 cc. at a time, waiting after each addition until the mixture has
assumed a pale brownish color. If this is not done the dye will be precipitated and can
then be reduced only with difficulty. The stannous solution should be at a tempera-
ture of 60-80°C. at the beginning of the operation. As reduction proceeds and the
solution becomes more dilute the temperature is raised to boiling; care must be taken,
however, that the mixture does not boil over after an addition of the dye as some heat
is generated by the reaction. The reduction is carried out conveniently in a tall beaker
of 1000-1200 cc. capacity. After all dye has been added and reduced, allow the mix-
ture to cool and make alkaline by the addition of about 75 grams of sodium hydroxide
dissolved in 150-200 cc. of water.
Cool the alkaline mixture and extract the cumidine by shaking it with two 200 ce.
portions of ether. Combine the ether extracts and wash with water until the alkali
and salts are removed. Evaporate the solvent on the steam bath but avoid prolonged
heating that would volatilize appreciable quantities of the base. Fractionate the
residue from a small side-necked flask, carefully avoiding overheating and collect
separately the fractions; (a) boiling below 220°C.; (b) boiling between 220 and 225°C.;
(c) boiling between 225 and 230°C.; and (d), boiling between 230 and 240°C. Weigh
the fractions to within 0.05 gram.
ORANGE II IN ORANGE I.
(Applicable when the proportion of Orange II is below 5 per cent.)
Dissolve 0.20 gram of dye in about 20 cc. of water and add 3-4 cc. of concentrated
hydrochloric acid. Shake in a separatory funnel with 50 cc. of amyl alcohol, then
draw off and discard the lower layer of liquid. Wash the amy] alcohol with six 50
ec. portions of N sodium carbonate solution made with such accuracy that it con-
tains between 51 and 55 grams of the salt per liter. A second funnel containing 50 cc.
of amy] alcohol is provided and each alkaline wash portion is drawn into this from the
first separator and again extracted before being discarded. Finally wash the solvent
in the second funnel with two additional 50 cc. portions of the carbonate solution.
Dilute the amyl alcohol portions with 1-2 volumes of gasoline and extract the dye
by washing with several portions of water. Determine the dye by titration against
standard titanium trichloride solution (in acid tartrated mixture) or by an accurate
colorimetric procedure.
IODEOSINE G IN ERYTHROSINE.
Mix 20 cc. of 0.020% solution of the dye with 20 cc. of concentrated hydrochloric
acid, cool and shake with 25 cc. of ether. Compare with blank tests carried out in
the same way with pure Erythrosine and with a mixture of 19 parts of this dye with
one of [odeosine G. With the pure Erythrosine the hydrochloric acid solution after
extraction will be colorless and on addition of excess of ammonium hydroxide will
remain so or show but a faint pink coloration. The acid used in the test with the
mixture will be tinged yellow and will become red on the addition of ammonium hy-
droxide.
ISOMERIC AND SIMILAR DYES IN AMARANTH.
Dissolve 0.100 gram of the dye in 40 cc. of water, add 10 cc. of 0.1 N benzidine solution
(9.2 grams base per liter in 0.5 N hydrochloric acid), mix the solution well and allow
to stand exactly 2 minutes. Filter through a folded filter and dilute 10 cc. of the
214 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
filtrate to 100 ce. Compare this solution colorimetrically with a standard Amaranth
solution containing 0.40 mg. of the dye per 100 cc. If it is not more intensely colored
than the standard solution the proportion of isomeric dyes may be considered to be
below 1.5 per cent.
SODIUM CHLORIDE IN DYES OR MIXTURES CONTAINING MORE THAN 25 PER CENT OF
THIS SUBSTANCE.
An amount of the material should be taken for the determination that will contain
0.10-0.15 gram of sodium chloride. Treat the filtered solution with a slight excess
of silver nitrate; add 5-10 cc. of concentrated nitric acid and an excess of 7% potassium
permanganate solution (about 15 cc. per decigram of organic matter present). Boil
the mixture for a few minutes, stirring to prevent bumping; then add sulfur dioxide
solution slowly with stirring until the oxide of manganese dissolves leaving white silver
chloride. Remove any excess of sulfur dioxide by boiling, cool and filter the silver
chloride on a weighed Gooch crucible, wash, dry and weigh in the usual manner.
SUCROSE IN DYE MIXTURES.
The procedure to be used will vary according to the nature of the other components
of the mixture. Sucrose is readily soluble in saturated solutions of sodium chloride,
sodium sulfate and potassium chloride and can be extracted from most dry dye mix-
tures with such solvents and estimated polarimetrically. The values found must be
corrected by comparison with the readings obtained with solutions of known sugar
concentration in the same solvent.
The barium salts of the color acids of indigo carmine, Naphthol Yellow S and Ery-
throsine are soluble with difficulty and that of Ponceau 3R is quite insoluble. Ery-
throsine is almost completely precipitated by lead acetate; Light Green S. F. Yellow-
ish forms compounds of low solubility with a-naphthylamine and similar bases.
ADDENDA.
SODIUM CARBONATE IN ERYTHROSINE.
(a) (Applicable with Erythrosine.)
Fic. 2. APPARATUS FoR THE EsTIMATION OF CARBON Dioxtpe AND ERYTHROSINE.
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS 215
Arrange the apparatus as illustrated in Fig. 2. The flask, A, is of about 600 ce.
capacity and is fitted with a doubly perforated rubber stopper through which passes
the stem of a small dropping funnel, B, reaching nearly to the bottom of the vessel,
and the delivery tube of a short reflux condenser, D. The dropping funnel, B, is con-
nected with a cylinder, C, by means of stoppers and glass and rubber tubing. The
cylinder should be of about 200 cc. capacity and contain a 3-inch layer of soda lime
held in place with glass wool or other suitable material. The condenser is connected
by means of a rubber stopper and glass tube with a piece of rubber tubing, F, which
can be connected either to the absorbing train or to an aspirator bottle or air pump.
The absorbing train consists of U-tubes, G, H, J, J, connected by means of rubber
stoppers and glass fittings. The U-tubes should be of such size that the arms are
about 5 inches in length and § inch internal diameter. A rubber tube leading to the
aspirator bottle or air pump is provided with two screw clamps or with some other
device that will permit the rate of flow of the air drawn through to be readily and
accurately adjusted, and is connected either to the last U-tube through the fitting,
K, or to the rubber tube, F’,, through a short glass tube.
In order to make the determination, charge the absorbing train by measuring exactly
10 ce. of a standard approximately 0.1 N barium hydroxide solution into each of the
U-tubes, adding a little boiled water when required so that in every case the lowest
part of the bend of the U-tube will be completely filled with liquid.
Place 10 grams of the dye, a few glass beads and about 250 cc. of water in the flask,
A, insert the stopper with its connections to the condenser and soda lime cylinder,
close the stop-cock of the dropping funnel and heat the mixture to boiling. The ab-
sorption train is not connected with the apparatus during this operation. After 1-2
minutes, turn down the burner so that the solution boils but slowly, open the stop-
cock of the separating funnel, attach the air pump connection to E and draw several
liters of air through the apparatus to wash out the carbon dioxide. Then disconnect
the pump from the tube, F, and insert the absorption train connecting it with the
rubber tube, F, and with the pump through K. Draw 200-500 cc. of air through the
apparatus, the dye solution being kept slowly boiling meanwhile. The barium hy-
droxide solution must remain clear, showing that all uncombined carbon dioxide has
been removed. Disconnect the air pump at K, close the stop-cock of the separatory
funnel, B, partially remove the stopper at S and pour a mixture of 4 cc. of concentrated
sulfuric acid and 10-15 cc. of water into the bulb of the funnel. Replace the stopper,
then open the stop-cock so that the acid may run into the dye solution. Then con-
nect with the air pump again at K and draw air through the boiling liquid and absorp-
tion train, at first slowly, finally more rapidly until all carbon dioxide has been carried
into the standard barium hydroxide. The solution in the last tube must remain clear.
Rinse the turbid portions of the standard solution into a 200 cc. Erlenmeyer flask
with boiled water, close the vessel with a stopper and Bunsen valve or other device to
prevent access of carbon dioxide, then heat the mixture to boiling to render the pre-
cipitated carbonate crystalline and less soluble. Finally cool and titrate carefully
with standard hydrochloric acid using phenolphthalein as indicator.
TABLE TO AID IN THE ESTIMATION OF DYES WITH STANDARD TITANIUM
TRICHLORIDE SOLUTION.
Dyes are designated by the numbers given in ‘“‘A Systematic Survey of the Organic
Colouring Matters’, 1904, by Arthur Green, based on the German of Schultz and
Julius. Dye numbers enclosed in parentheses refer to closely related derivatives.
It is assumed that the titrations are carried out under such conditions that the dyes
are reduced as stated by Knecht and Hibbert, ‘““New Reduction Methods in Volu-
metric Analysis’’, 1918.
216 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Molecular weights are calculated from the values adopted in 1920, oxygen being
taken as 16.
TABLE 1.
Estimation of the dyes with standard titanium trichloride solution.
AMOUNT OF
.1 N
eee | DYE EQUAL TO
yee MOLECULAR | anicHLORIDE LoG 1 cc. or 0.1 N LOG
WEIGHT EQUAL TO (MANTISSA) TITANIUM (MANTISSA)
1 GRAM OF TRICHLORIDE
DYE
ce. gram
1 193.06 931.9 0.9694 0.001073 0.0306
3 256.11 468.1 0.6708 0.002134 0.3292
3 (+420) 1 274.12 437.8 0.6413 0.002284 0.3587
4 358.16 335.1 0.5251 0.002985 0.4749
7 (Base) 197.17 202.9 0.3073 0.004929 0.6927
8 401.27 99.72 0.9988 0.01003 0.0012
9 429.32 92.76 0.9694 0.01073 0.0306
10 214.19 186.7 0.2712 0.005355 0.7285
11 248.19 161.2 0.2073 0.006205 0.7927
13 350.24 114.2 0.0577 0.008756 0.9423
14 452.29 88.41 0.9465 0.01131 0.0535
15 452.29 88.41 0.9465 0.01131 0.0535
16 225.21 177.6 0.2495 0.005630 0.7505
17 248.69 160.8 0.2064 0.006217 0.7936
18 262.71 152.3 0.1826 0.006568 0.8174
1
43 364.26 109.8 0.0407 0.009106 0.9593
44 466.31 85.74 0.9332 0.01166 0.0668
55 480.32 83.28 0.9205 0.01201 0.0795
56 494.34 80.91 0.9080 0.01236 0 0920
64 502.33 | 79.62 0.9010 0.01256 0.0990
|
65 502.33 { 79.62 0.9010 0.01256 0.0990
84 316.24 126.5 0.1021 0.007906 0.8979
85 350.24 | 114.2 0.0577 0.008756 0.9423
86 350.24 114.2 0.0577 0.008756 0.9423
87 327.26 122.2 0.0871 0.008181 0.9129
88 375.29 106.6 0.0277 0.009382 0.9723
89 477.34 83.83 0.9234 0.01193 0.0766
94 (Na 2) 512.31 77.62 0.8900 0.01288 0.1100
94 (Na 3) 1 534.30 74.85 0.8742 0.01336 0.1258
95 | 375.29 106.6 0.0277 0.009382 0.9723
101 400.28 100.0 0.0000 0.01000 0.0000
102 400.28 100.0 0.0000 0.01000 0.0000
103 502.33 79.62 0.9010 0.01256 0.0990
105 502.33 79.62 0.9010 0.01256 0.0990
106 604.38 66.18 0.8207 0.01511 0.1793
107 604.38 66.18 0.8207 0.01511 0.1793
108 706.43 56.62 0.7530 0.01766 0.2470
137 448.33 178.4 0.2515 0.005604 0.7485
138 556.37 143.7 0.1577 0.006955 0.8423
146 556.37 143.7 0.1577 0.006955 0.8423
1921] MATHEWSON: REPORT ON COLORING MATTERS IN FOODS ala
TasLe 1.—Continued.
Estimation of the dyes with standard tilanium trichloride solution.
AMOUNT OF
0.1.N
TITANIUM DYE EQUAL TO
MOLECULAR | TRICHLORIDE LOG lcc. or 0.1N LOG
DYE WEIGHT EQUAL TO (MANTISSA) TITANIUM (MANTISSA)
1 GRAM OF TRICHLORIDE
DYE
| ; ce. gram
150 | 380.31 210.4 0.3229 0.004754 0.6771
169 584.41 136.9 0.1364 0.007305 0.8636
197 419.23 190.8 0.2807 0.005240 0.7193
201 461.30 169.9 0.2302 0.005766 0.7609
240 696.51 114.9 0.0602 0.008706 0.9398
254 932.61 85.74 0.9332 0.01166 0.0668
269 554.33 144.3 0.1594 0.006929 0.8406
287 726.51 110.2 0.0419 0.009081 0.9581
319 992.65 80.60 0.9063 | 0.01241 0.0937
329 652.47 122.6 0.0885 | 0.008156 0.9115
372 780.53 230.6 0.3629 0.004336 0.6371
398 604.30 132.4 0.1219 0.007554 0.8781
427 (Chloride) 364.89 54.83 0.7390 0.01824 0.2610
427 (Ozalate) 926.94 43.16 0.6351 0.02317 0.3649
427 (Base) 346.44 57.75 0.7615 0.01732 0.2385
427 (hydr. Zn Salt) 1403.28 42.76 0.6310 0.02339 0.3690
433 (Na2) 730.60 27.37 0.4373 0.03653 0.5627
(433) 690.59 28.96 0.4618 0.03453 0.5382
435 (Na3) 832.65 24.02 0.3806 0.04163 0.6194
(435) 792.64 25.23 0.4020 0.03963 0.5980
447 (Chloride) 323.72 61.77 0.7908 0.01619 0.2092
447 (C1+4H,0 395.78 50.53 0.7035 0.01979 0.2965
451 (Penta) 393.83 50.78 0.7057 0.01969 0.2943
452 407.85 49.05 0.6906 0.02039 0.3094
452 (+8 H:0) 551.97 36.23 0.5591 0.02780 0.4409
462 (Na Salt) 611.43 32.71 0.5147 0.03057 0.4853
625.45 31.98 0.5048 0.03127 0.4952
464 567.51 35.24 0.5470 0.02838 0.4530
468_ 801.71 24.98 0.3975 0.04004 0.6025
479 797.59 25.07 0.3992 | 0.03988 0.6008
491 616.48 32.44 0.5111 * 0.03082 0.4889
504 478.85 41.77 0.6209 0.02394 0.3791
510 (Na Salt) 376.18 53.16 0.7256 0.01881 0.2744
510 (Acid) 332.20 60.20 0.7796 0.01661 0.2204
512 691.83 28.92 0.4611 0.03459 0.5389
516 (Na Salt) 628.00 31.85 0.5031 0.03140 0.4969
517 (Na Salt) 879.83 22.73 0.3566 0.04399 0.6434
517 (Acid) 835.84 23.92 0.3789 0.04179 0.6211
518 (Na Salt) 760.73 26.28 0.4197 0.03804 0.5803
520 (K Salt) 980.93 20.39 0.3094 0.04904 0.6906
218 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Tasie 1.—Concluded.
Estimation of the dyes with standard titanium trichloride solution.
AMOUNT OF
0.1N DYE EQUAL TO
DYE MOLECULAR TITANIUM LOG 1 cc. or 0.1 N LOG
WEIGHT TRICHLORIDE| (MANTISSA) TITANIUM (MA NTISSA)
EQUAL TO 1 TRICHLORIDE
GRAM OF DYE
ce. gram
523 (K Salt) 1049.84 19.05 0.2799 0.05249 0.7201
523 (Na Salt) 1017.64 19.65 0.2934 0.05088 0.7066
584 350.74 57.02 0.7560 0.01754 0.2440
364.76 54.83 0.7390 0.01824 0.2610
604 601.42 33.26 0.5219 0.03007 0.4781
639 (Chloride) 310.69 64.41 0.8089 0.01553 0.1911
650 (Chloride) 319.77 62.55 0.7962 0.01599 0.2038
650 (Zn Salt) 793.84 50.37 0.7022 0.01985 0.2978
692 466.28 42.87 0.6322 0.02332 0.3678
693 670.37 29.84 0.4747 0.03352 0.5253
Benzene-azo-b- 247.21 161.8 0.2090 0.006180 0.7910
Naphthylamine
Toluene-azo-b- 261.24 153.1 0.1850 0.006531 0.8150
Naphthylamine
Sodium trimethyl 392.29 102.0 0.0085 0.009807 0.9915
benzene-azo-b-
naphthol-sul-
fonie acid.
Sodium indigo 364.23 54.92 0.7397 0.01821 0.2603
sulfonate
TABEE) 2:
Sulfur and sodium in some coal tar dyes.
SODIUM SULFATE
DYE SULFUR SODIUM CORRESPONDING TO
SODIUM CONTENT
per cent per cent per cont
Naphthol Yellow S 17.91 12.84 39.67
Ponceau 3R 12.97 9.31 28.74
Orange I 9.15 6.57 20.28
Tartrazine (Trisod. Salt) 18.01 12.91 39.88
Tartrazine (Disod. Salt) 12.51 8.98 27.72
Amaranth 15.92 11.41 35.26
Light Green S. F. Yellowish
(Trisod. Salt M W 832.6) 11.55 8.38 25.60
Light Green S. F. Yellowish
(Disod. Salt M W 792.6) 8.09 5.06 15.62
Erythrosine 0.0 5.23 16.14
Indigo Disulfoacid 13.75 8.59 26.54
edt tte
1921] CLARKE: REPORT ON METALS IN FOODS 219
REPORT ON METALS IN FOODS.
By W. F. Criarke (Bureau of Chemistry, Washington, D. C.), Referee.
ARSENIC.
The referee was instructed to rewrite the Gutzeit method in form for
adoption as official. It was not possible to secure a copy of the printed
revised methods in time to go over the arsenic method, as finally revised
for printing, with reference to making any changes that might seem
necessary before recommending its adoption as final. At the meeting
of the American Chemical Society in April, 1919, H. V. Farr presented
a paper, as yet unpublished, on the Gutzeit method which contained
some valuable modifications of the present methods. In his procedure
Farr returns to the older technique of passing the arsine against the
sensitized paper instead of along a strip. The special apparatus which
he uses is probably more satisfactory for tests where the chief question
is whether or not the amount of arsenic exceeds a definite limit. Since
a large amount of the work of this association is of this nature rather
than the actual measurement of quantities which vary considerably, it
is probable that Farr’s method and apparatus should be given consider-
ation with reference to adoption as official by this association.
TIN.
Collaborative work has been carried out using the Penniman method!
with the following modifications:
(1) For making the standard solution of potassium iodate a supply
of the salt was used which had been dried at 120° to 130°C. for 3 or
more hours. The solution was standardized against standard thio-
sulfate solution after the addition of hydrochloric acid and an excess of
potassium iodide?.
(2) Since potassium iodate with potassium iodide in the presence of
hydrochloric acid yields free iodine, and also because iodine sufficient to
color the starch was liberated in all the cases studied, potassium iodide
was not added.
(3) The starch paste was made by adding 5 grams of thick cold water
starch paste to 1 liter of boiling water and boiling for 2 additional min-
utes.
(4) Since all results obtained by most of the collaborators were very
low, no blanks were run on the zinc. Blanks could only cause a reduc-
tion in the figures and the value of the blanks would be negligible.
(5) Since the expression ““Titrate to strong blue color” is indefinite,
the usual faint, but permanent, blue was used.
1 J. Assoc. Official Agr. Chemists, 1920, 4: 172.
2F. P. Treadwell and W. T. Hall. Analytical Chemistry. 5th ed., 1919, 2: 670.
220 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
RESULTS.
Samples of standard tin solution and of composite, well-mixed canned
pumpkin were furnished to all of the collaborators. The results obtained
are shown in the following tables:
TABLE 1*.
Coliaborative results on standard tin solution.
(Analyst, M. B. Porch, H. J. Heinz Co., Pittsburgh, Pa.)
PENNIMAN PENNIMAN PENNIMAN BAKER-SELLARS GRAVIMETRIC
METHOD} METHOD} METHOD § METHOD** METHODff
Tin Tio Tin Tin Tin Tin Tin Tin Tin Tin
present found present |} found present | found present | found present found
mg. mg. mg. mg. mg. mg. mg. mg. mg. mg.
41.67 | 41.90 | 41.67 | 44.60 | 41.67 | 39.40 | 41.67 | 41.00 | 41.67 43.90
41.67 | 42.50 | 41.67 | 44.60 | 41.67 | 39.70 | 41.67 | 43.00 | 41.67 45.20
41.67 | 43.70 | 41.67 | 44.20 41.67 | 44.00
41.67 | 42.10 | 41.67 | 44.90 | ..... | ..... | 41.67 | 43.75
41.67 | 43.60 | 41.67 | 44.90 | ..... | ..... | 41.67 | 39.55
Tense ssoue ESRB alin gese | Sacuee (case Issa
83.33 | 85.30
83.33 | 89.11
83.33 | 86.90
83.33 | 87.50
*See remarks following Table 3.
{Starch and chloroform both used; end point read when starch showed strong blue and chloroform first
showed pink.
{Starch only used; end point read when starch showed strong blue.
§Starch only used; end point read when starch showed faint but permanent blue.
**Assoc. Official Agr Chemists, Methods. 2nd ed., 1920, 150.
ttlbid., 149.
= tg tet
1921] CLARKE: REPORT ON METALS IN FOODS 221
TABLE 2.
Collaborative results on standard tin solution*.
PENNIMAN METHOD BAKER-SELLARS
METHOD
SNELIEE Tin | Tin found
Tin found (chloro- Tin Tin
present (starch form present found
indicator) | indicator)
K. mg. mg. mg. mg. mg.
A. E. Stevenson, National Canners | 41.67 31.80 arate 41.67 37.80
Association, Washington, D. C. 41.67 31.30 ae 41.67 37.20
41.67 34.80 aan 41.67 38.50
83.33 65.10 Kersh: 83.33 74.30
83.33 69.90 Ligees 83.33 74.20
83.33 75.50 BROT 83.33 75.00
G. C. Spencer, Bureau of Chemistry, | 83.33 79.37 90.07
Washington, D. C. 83.33 78.02 90.37
83.33 71.70 82.90
83.33 75.24 85.50
J. K. Morton, Bureau of Chemistry, | 83.33 76.30
Washington, D. C. 83.33 77.65
83.33 80.70
83.33 78.40
83.33 78.60
83.33 77.40
R. M. Hann, Bureau of Chemistry, | 83.33 77.00
Washington, D. C. 83.33 76.80
83.33 76.40
83.33 76.80
83.33 76.40
W. F. Clarke 41.67 38.20 Be ece 16.67 16.87t
41.67 37.65 ee 16.67 16.78t
41.67 38.00 : Aoace breve
41.67 36.65
41.67 37.25
41.67 37.30
41.67 37.90
41.67 34.30
83.33 71.10
83.33 73.40
*Wherever starch was used as the indicator, the end point was read when the faint but permanent blue
color was first obtained. Where chloroform was used the end point was read when the pink color dis-
appeared.
tResults obtained after precipitation of the tin by hydrogen sulfide for 1 hour at room temperature,
the sulfide being filtered on thick asbestos with gentle suction. When reducing the tin solution 150-175
ec. of concentrated hydrochloric acid (37 %) were used.
APPLICATION OF THE PENNIMAN METHOD TO THE ANALYSIS OF STANDARD
TIN CHLORIDE SOLUTION.
Unless otherwise noted, in all the analyses by the Penniman method
recorded in Tables 1 and 2, the solution was brought to a concentration
of ammonium chloride and of free hydrochloric acid and to a volume
222 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
equal to that indicated in cases in which the hydrochloric acid extrac-
tion is necessary. After the adjustment of the concentration of the acid
and of the ammonium salt, the method was followed closely unless
exceptions to the contrary are noted.
TABLE 3.
Collaboratwe resuils on the analysis of pumpkin.
PENNIMAN BAKER-SELLARS GRAVIMETRIC
METHOD METHOD METHOD
ANALYST
Tin found Tin found Tin found
mg. mg. mg.
M. B. Porch 44.30* 44.00 39.40
44.70* 43.75 39.70
41.00* 40.00 were
A. E. Stevenson 43.63 50.37
41.63 50.25
40.63 47.75
Fests 46.75
G. C. Spencer 36.30 46.52
27.03 46.42
R. M. Hann 37.40
40.20
36.80
40.70
42.60
43.00
W. F. Clarke 42.60 44.62+
42.35 46.40f
44.20 47.40}
44.03 47.95+
41.90 47.63f
41.68 ieee
39.20
38.20
39.00
*Strong blue starch end point.
tMethod modified as described for Clarke's results in Table 2.
Norre.—In Table 3 generally 50-gram samples were used; otherwise
all results are figured on the basis of 50-gram samples. In no case was
the chloroform end point used.
REMARKS.
With regard to the Penniman method, Porch states that he standard-
ized the iodate solution against metallic tin; that he used generally
25 cc. of 31 per cent hydrochloric acid when precipitating the tin by
zinc; that he tried to bring his titration end points to the same strong
1921] CLARKE: REPORT ON METALS IN FOODS 223
blue shade in all cases, except as noted in Table 1; that he used as a
chloroform end point the first pink that appeared; that he added the
specified amount of potassium iodide in all cases; and that he found
chloroform unsatisfactory in the pumpkin work.
Regarding the Penniman method, Stevenson notes that the results
are low and non-concordant. Lacking time, he was unable to de-
termine the causes of the discrepancy but thought the tin was probably
incompletely reduced.
ACCURACY OF THE STARCH END POINT IN THE OXIDATION OF THE
STANNOUS CHLORIDE.
To test the usefulness of the starch end point as a mark of the com-
pletion of the oxidization of the stannous chloride by the iodate solution
in the Penniman method, the referee carried out some determinations in
which metallic tin and zinc were placed in the Erlenmeyer flasks,
carbon dioxide passed through, the metals dissolved in hydrochloric
acid and, after cooling, the stannous chloride was titrated with iodate
solution.
TABLE 4.
Oxidation of stannous chloride by potassium icdale.
ZINC TIN PRESENT TIN FOUND
grams mg. mg.
3 30.80 28.90
6 30.60 26.80
3 38.10 36.70
It is seen from Table 4 that the starch end point does not mark the
completion of the oxidation of the stannous chloride by the iodate
solution, liberation of free iodine taking place prior to the completion
of the oxidation.
GENERAL DISCUSSION.
It is evident that better results are obtainable by, the Baker-Sellars
method than by the Penniman method in its present form. The one
collaborator, Porch, who tried to make use of a strong blue end point
obtained figures which were rather high in the case of the standard tin
solution, whereas all results were low when the faint blue end point was
used. It is believed that the concentration of free hydrochloric acid
plays an important role in the completeness of the precipitation of the
tin by the zinc. Probably such a quantity of acid should be used as
will permit an excess of zinc to remain undissolved, thus preventing
any tendency of the tin to go back into solution. Attention is called
to the fact that the concentrated hydrochloric acid furnished recently
224 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
by the dealers seems to be quite variable as to the percentage of acid
actually present, the values ranging between 31 and 37 per cent. In
cases in which it is essential to have a definite concentration or in which
only an acid of high concentration will serve, this irregularity may
result in drawing wrong conclusions.
Possibly empirical conditions might be established which would per-
mit of the use of the starch end point as a mark of the completion of
the oxidation of the stannous chloride. Possibly a satisfactory way
of using the chloroform end point might be found. Finally, the use of
standard iodine solution might serve to make the method accurate.
So far as the referee is concerned, however, it is not apparent that the
method is more rapid in respect to actual manipulation net time as
compared with the Baker-Sellars method.
RECOMMENDATIONS.
It is reeommended—
(1) That the Gutzeit method and apparatus for the determination
of arsenic, as described by H. V. Farr, be studied and tested by col-
laborative work in comparison with the present Gutzeit method.
(2) That the tentative methods for copper and zinc! be studied by
collaborative work and that any other apparently desirable methods be
studied similarly.
(3) That the tentative volumetric method for tin? be made the sub-
ject of further study, with a view to modification, and that collaborative
work thereon be conducted.
(4) That the Penniman method for tin be studied further with a
view to revision or radical modification.
(5) That metals for which no methods have been studied by this
association be studied in the order of their toxicity, the likelihood of their
occurrence in foods being given first consideration.
REPORT ON PECTIN IN FRUITS AND FRUIT PRODUCTS.
By D. B. Bisset (U. 8. Food and Drug Inspection Station, Old Custom
House, St. Louis, Mo.), Referee.
A number of samples were sent out for collaborative work, together
with copies of methods to be employed. Only one collaborator sub-
mitted a report and her results and those of the referee indicate that
the methods employed, while recognizing the addition of pectin to
fruits which do not normally contain any material amount of pectin,
1 Assoc. Official Agr. Chemists, Methods, 2nd ed. .1920, 151,
2 Tbid., 150.
1921] BIGELOW: REPORT ON CANNED FOODS 225
do not differentiate between the addition of pectin and the addition of
so-called apple base.
RECOMMENDATION.
It is recommended—
That the methods for the detection of added pectin in fruit products
receive further study.
F. B. Power (Bureau of Chemistry, Washington, D. C.) presented a
paper on “The Detection of Methyl Anthranilate in Fruit Juices’.
REPORT ON CANNED FOODS.
By W. D. BicEtow (National Canners Association, 1739 H Street, N. W.,
Washington, D. C.), Referee.
Your referee was asked to give special attention to methods for the
detection of spoilage in canned foods. This subject has been studied
but its complexity is so great that a report of progress is all that can be
made at this time.
Apparently the question involves the bacteriological condition of the
foods, chemical examination for the detection of the products of metab-
olism of spoilage organisms, and the critical examination of the con-
tainers. Much progress has been made in the development of methods
along these lines for the determination of the cause of spoilage. Methods
adapted to securing data of value to regulatory officers, however, involve
some further complications. The following thoughts suggest them-
selves regarding such methods:
Organoleptic methods.—This type of method is one of the most im-
portant for the examination of canned foods. The analyst must be
conyersant with the food he is examining, must know its appearance,
color, odor, and taste. An analyst thus qualified is better able to judge
of the soundness of a sample by an organoleptic examination than by
examination by means of bacteriological and chemical methods. The
results of an organoleptic examination suggest questions which can
often be answered by bacteriological or chemical examination.
Bacteriological methods.—When the organoleptic examination shows
the product to be sound and when the can is found to be tight a bacterio-
logical examination is usually superfluous, provided the product has
been upon the open market and thus is known to have been canned
long enough to permit bacteria which may be present to develop. When
the organoleptic examination shows that the product is abnormal a
bacteriological examination will often disclose the reason. When the
1 J. Am. Chem. Soc., 1921, 43: 377
226 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
product has an abnormal taste or odor, however, and is found to be
sterile the microscopic examination of a hanging drop sometimes gives
evidence of spoilage before sterilization. The presence of viable organ-
isms in the sealed can does not prove that the product is undergoing
spoilage. It not infrequently happens that bacterial spores are present
whose resistance to heat is so great that they were not destroyed by the
process to which the food was subjected but which do not germinate
because of the acidity or of other characteristics of the product under
examination. Again, the spores may only germinate at relatively high
temperatures and thus, in ordinary storage, remain as spores indefi-
nitely. The sterility of the sample, therefore, can not be made the
sole criterion in judging of the soundness of canned food.
Chemical methods.—Certain products of bacterial spoilage, such as
high acidity, may be detected by chemical methods. Since this ques-
tion, however, is not peculiar to canned foods it would not appear to
be appropriate to discuss it here.
Examination of the can.—Whenever a sample of canned food gives
evidence of incipient spoilage by taste or odor, or when examined by
bacteriological methods is found to be unsterile, a careful examination
of the can should be made. By this it is not meant that the external
appearance of the can should be noted. Leaks which cause spoilage in
canned foods are not usually apparent from the outside. The seams
should be filed and the construction of the can carefully noted. The
procedure necessary in each case depends on the style of can and often
on the character of the product canned. This procedure varies from
time to time as changes are made in can manufacture and in methods
of sealing cans. The technique required is difficult to explain and for
that reason the analyst should receive personal instruction from one
familiar with the industry.
No report on the physical methods of the examination of canned
foods was made by the associate referee.
No report on tomato products was made by the associate referee.
EFFECT OF THE USE OF DIFFERENT INSTRUMENTS IN
MAKING A MICROSCOPIC EXAMINATION FOR MOLD
IN TOMATO PRODUCTS.
By B. J. Howarp (Bureau of Chemistry, Washington, D. C.).
The question has been raised from time to time as to what influence,
if any, the form of sampling instrument with which the test drop is
taken has on the percentage of fields containing mold in connection
1921] HOWARD: MICROSCOPIC EXAMINATION OF TOMATO PRODUCTS 227
with the microscopical examination of tomato products. The method!
states that, ““A drop of the product to be examined is placed on a micro-
scopic slide and a cover glass is placed over it * * *”*. Naturally,
as a result of this vagueness, analysts used various instruments such as
scalpels, penknives, glass rods, platinum loops, pipets, etc. In 1916,
when the method was adopted as tentative the directions concerning
this point were stated as follows?: ““Remove the cover [of mold counting
cell] and place, by means of a knife blade or scalpel, a small drop of the
sample upon the central disk; * * * * ”. Although this is more
definite than the original statement, the question has been raised that
the size and shape of the scalpel might have sufficient influence on the
character of the drop to modify the count.
In order to study the question, two tomato samples were prepared
as follows:
Unconcentrated cyclone juice was prepared by making a mixture of
95 parts of apparently sound tomatoes with 5 parts of rotten stock and
pulping in a commercial cyclone. The second sample was made from
a portion of the first by boiling it down to one-half of its original volume.
The instruments used for taking the test drops were: (a) A large scalpel
(blade about 40 mm. long); (b) a medium scalpel (blade about 31 mm.
long); (c) a sharp-pointed scalpel; (d) a glass rod; (e) a platinum loop;
(f) a pipet (touching the point to the slide); (g) a pipet (allowing the
sample to drop freely from the point; and (h), the forefinger of the
operator.
In order to eliminate so far as practicable the analyst variation the
series of tests was made by each of three microscopists. In order fur-
ther to eliminate the individual personal equation, three tests were
made by each analyst by each method of sampling. In most of the
cases each analyst made but one test by each method of sampling on
any one day. Furthermore, none of the results were calculated till
the data for the entire series had been obtained. Finally, the results
were calculated and the average count by each method of sampling
obtained.
1U.S_ Bur. Chem. Circ. 68: (1911), 3. -
2 Assoc. Official Agr. Chemists, Methods. 1916, 324.
228 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Summary of
UNCONCENTRATED JUICE
METHOD IOF SAMPLING Average Average Average Group Results
of of of tn
Analyst Analyst Analyst Average Variation
A B G count
Sharp-pointed sealpel 63 54 "55 57 9
Medium scalpel 57 54 55 55 3
Large scalpel 51 55 56 53 5
Glass rod 43 54 61 53 18
Pipet (touching slide) 59 46 47 51 12
Pipet (dropping free) 56 53 59 56 6
Platinum loop 62 63 57 61 6
Forefinger 65 54 49 56 16
DISCUSSION OF RESULTS AND COMMENTS.
From a study of the results, as shown by the final averages, it appears
that the smallest average variations were obtained by the use of the
medium and large scalpels. The average range between the results of
the three analysts was 5.5 points. This was true of each sample of
pulp considered individually. The widest range of results was noted
where the glass rod was used for sampling, the variation being 17 points.
In using the pipet it was noted that more or less difficulty was ex-
perienced in getting the pulp to flow from the orifice which was only
about ? mm. in diameter. This led to the conclusion that better results
might have been obtained if a pipet with a larger orifice had been em-
ployed. In a separate set of tests it was further shown to be possible
with a pipet to so manipulate the taking of the sample as to get very
low counts on products which actually were high in mold, this variation
being influenced by the manner in which the drop was released from the
pipet. This fact argues strongly against this instrument for taking
the drop.
In using the scalpels the-sample was well stirred and the test drop
taken by a quick, scooping motion during which the point of the instru-
ment was plunged about 1 to 14 cm. into the pulp and quickly raised,
carrying with it a representative portion of the material which was quickly
placed on the slide, previously cleaned and polished.
1921] WILEY: ADDRESS BY THE HONORARY PRESIDENT 229
mold tests.
CONCENTRATED JUICE RINATS AVERAGES (OF
TWO GROUPS
Average Average Average Group Results
oe ce Gi Count Variation
Analyst Analyst Analyst Average Vanintion 3
A B Cc count
70 56 69 65 14 61.0 12.5
64 67 72 68 8 61.5 5.5
~ 74 70 70 71 6 62.0 5.5
65 60 76 67 16 60.0 17.0
50 60 50 53 10 52.0 11.0
61 59 71 64 12 60.0 9.0
59 57 74 58 17 59.5 11.5
61 60 54 67 a 61.5 11.5
President Lythgoe.—It is the custom of this association to change the
president every year, but we have one president who does not change.
About twenty-three years ago I started doing food work, and either I
had more time on my hands then than I have now, or my mind was
more agile, but I read more of the work published by the agricultural
chemists of this and other countries. I desired to get acquainted with
the personality of the people who were doing this great work, and of
all the men who were publishing work it seemed to me that the biggest
one was our present Honorary President. It is possible that might
have been due to youthful enthusiasm, but I am somewhat more mature
now, and I am quite proud to state that I consider my youthful
judgment to have been quite accurate, and [ still consider our friend,
the Honorary President of this association, the king-pin of the workers
in this line. Friends, I take great pleasure in introducing to you our
Honorary President, Dr. Harvey W. Wiley. (Great Applause.)
ADDRESS BY THE HONORARY PRESIDENT.
H. W. Witey (Good Housekeeping, Bureau of Foods, Sanitation and
Health, Washington, D. C.)..
_ Our friend, Mr. Einstein, discovered what he considered a new con-
dition of affairs, but we all know that it was an old discovery for ever
since we have been able to think we have understood that we measure
all things by comparison with other things. Therefore, the doctrine
of relativity is by no means a new one. I, especially, feel impressed
with the truth of that doctrine as I look over this audience and compare
it with the humble beginnings of this association. I believe there is
one other gentleman present who, with me, was present at the original
meeting of this association. It really began to bud in this city in 1880,
230 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
again the same year in Boston, and the next year in Cincinnati, but it
was allowed to languish for some time until some of our friends in
Georgia took it up and, in combination with the then Commissioner of
Agriculture, J. T. Henderson, a meeting was called in Atlanta, Ga., in
May, 1884. There, a more definite plan was talked over, and it was
agreed to present this plan for final adoption at the meeting of the
American Association for the Advancement of Science in Philadelphia
in September of that year. We gathered around a small table. Elec-
tric lights were not known then; and stenographers were very scarce.
We did not need any, by the way, to take down what was said because
we took it down ourselves from mugs, various mugs upon the table.
There is a good deal of relativity in that because mugs have now dis-
appeared; we can only recall them by memory. E. H. Jenkins was the
presiding officer at this meeting—known to fame as Jolly Jenkins. I
wish he were able to come to this meeting. What a glorious thing it
would be if Jenkins could walk in here and be greeted by you as you
have greeted me! He was one of the great workers in the early days of
this association, and W. J. Gascoyne, whom you all know, was there;
and John Myers, who is dead and passed away; and Clifford Richard-
son, and C. W. Dabney, who afterwards grew to great proportions as a
college president.
There is another way to compare this association, and that is by the
men that it has produced, and the places where it has met. It is a
long distance from the little hall in the Eutopian Club in Philadelphia
to this grand place in the Willard Hotel. We are getting up in the
world every year. I do not know where we are going to go after we
leave here, but I suppose we will have our next meeting in the White
House, and may be one of our men will be there because we have already
sent one man to the Senate. So you see the doctrine of relativity is of
some considerable importance.
I want to say a few words about some of the work that is now con-
sidered of prime importance along the line of your investigations—
some work that I have not personally engaged in, except by following
closely the workers and their results, but still work of wonderful magni-
tude. The work along the science of nutrition, which is peculiarly a
work of this association, has gone forward by great strides in the last
few years, and we are now beginning to see clearly the significance of it
all. We have been seeking an ignis faltuus perhaps for several years
in this line, trying to find some definite chemical formula for the vita-
mines, so-called. That quest is about ended. I think the consensus of
opinion is now following the theory which I advocated some years ago
that these bodies were mere accelerators or enzymes. The present
opinion of investigators is that a vitamine is not a definite chemical
compound, in the sense of the word that you can take out and measure
1921] WILEY: ADDRESS BY THE HONORARY PRESIDENT 231
and determine what it is but that it is an infinitesimal element of matter,
known as the accelerator or enzyme, which is really the vitamine that
does the wonderful work in nutrition. If you take yeast, for instance
(I am not an advance guard of Fleischmann or anything of that kind),
which is very rich in a certain form of vitamine, and extract it, as I
heard Atherton Seidell describe last Thursday night in his retiring
address as President of the Washington Chemical Society, by adsorption
you will find this product just as it was before; something has been
removed of vital importance, of tremendous, vital importance, yet
nothing ponderable has been removed. Hence, that is one of the
reasons which led us to believe that it is an enzyme which does this
work.
There is another relativity there. We have been sneering at our
friends, the homeopathists for many years because they give nothing.
They so dilute their remedies that there are practically none present
and we say that you can not expect any great effect to come from nothing;
nothing will produce nothing, according to the laws of nature. But
after all, it may be that there is some virtue in the claims of our homeo-
pathic friends, and that they may, if they can get hold of it, have a
very dilute reagent which can produce wonderful results. When you
consider that there is a difference between life and death in that one
vitamine that prevents the development of beriberi, polyneuritis, and is
the thing that is imponderable, so far as any means of our investigation
are concerned, you begin to see the great value of the infinitely small.
I once defined astronomy as the chemistry of the infinitely great, and
chemistry as the astronomy of the infinitely small because one deals
with infinitely large bodies and the other with infinitely small bodies,
each of which is of equal importance in the cycle of life.
And so this vitamine which protects us against beriberi and poly-
neuritis, which is the same thing, is an imponderable substance. We
can not expect to get it out of food and weigh it. We want to determine
just what kind of an enzyme it is, and test the reactions of other digestive
enzymes which attach themselves to these reagents. You can extract
from the saliva the ptyalin; you can extract from the juices of the
stomach the pepsin, and so forth. They all have the same chemical
reaction as vitamines. This has been a wonderful investigation and
of great importance to human nutrition.
And then the fact that the vitamine is of different kinds, which was
not recognized by Funk and the early investigators, is of tremendous
importance in human welfare. There are at least three kinds of vita-
mines; there may be more; we can not tell; we know that there are two
or three or four different kinds of enzymes which proceed from the
digestive functions. We know of the secretions from the endocrine
glands which are of such vital importance to the growth and welfare of
232 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
the body. They are infinitely small; they are imponderable so far as
our account goes. These are wonderful truths which have come to
light by the investigations of men engaged particularly in your line of
work, and this is only the beginning of this kind of investigation. In
my opinion it will go still further and will accomplish still greater results
for human welfare and human happiness than have already been ob-
tained.
It is a remarkable fact that the lower animals have recognized the
existence of enzymes and vitamines from time immemorial. The
human animal is the only dumb animal in creation—almost—and it is
the most helpless animal in creation. We pride ourselves about belong-
ing to the Homo sapiens. I think we belong rather to the Homo
insapiens. We are the last of the animals to appreciate the vitamines.
When the bear or the wild animal kills another animal, he does not
eat the first thing he sees. He seeks out the glands which have vita-
mines in them. He eats the heart and the liver and the pancreas and
the kidneys first of all, and then if his hunger is satisfied he leaves the
rest of the animal until the next day. He does not eat the flesh that
we eat. We throw away the glands which have vitamines when we
kill an animal. I always want the gizzard, at least, when you kill a
chicken, but most people do not care for that. We eat the body first
while the wild animal eats the glands where the fat-soluble enzymes
reside. If there be any vitamines in the body at all they are in the fat
that surrounds these vital organs of the body. That is the only part
of the body that contains any vitamines of importance, and the animals
always eat those parts first.
Seidell told of a curious experiment in feeding chickens with white
flour and whole-wheat flour. They wanted to prepare it so that the
chickens could eat it in the ordinary way, so they made a kind of spaghetti
out of it, and they gave the chickens on the one hand these fragments
- made out of white flour, and those on the other side the fragments made
out of whole-wheat flour. The chickens that ate the white flour all died
of beriberi in thirty-five days, while the others were perfectly well at
the end of that time. This is a great lesson in itself, but we do not
heed it. We feed our children white flour, although we know it kills
chickens, and we do not feed them whole-wheat flour, although we
know it keeps the chickens alive. That is another evidence that man
belongs to the Homo insapiens group. The question is, how much of
this good food will protect the chickens that eat the bad food. That is
an important physiological problem. So they began by mixing ten per
cent of the good food with ninety per cent of the bad food. And what
happened? These chickens, that have no intellect at all, picked out all
of the fragments that came from the whole wheat side, and left all
that came from the other kind. They did it instinctively in any mix-
1921] WILEY: ADDRESS BY THE HONORARY PRESIDENT 233
ture that was given to them—they picked out the good food and left
the bad food alone. So spaghetti was made out of the mixed flour, and
in that way it was found that with about fifty per cent of the good flour
the chickens could be protected pretty well against beriberi or polyneu-
ritis. So you see these ideas of nutrition which we have just learned
have been known by the lower, wiser animals from time immemorial.
It is a great comment on human intelligence, is it not?
_ There is another line of investigation which lately came to my atten-
tion which I think is very interesting, and that is the investigation into
botulism. I have just come from the Pacific Coast, and one particular
thing which took me out there was to make a study of this problem at
the source, and there I met these wonderful investigators who are going
into this problem: one or two of them from the Bureau of Chemistry;
the representatives of the two great universities in California,—the
University of California and the Leland Stanford Jr. University; and
the Bureau of Public Health which had one of its most important in-
vestigators out there joining in this work.
A great prejudice has been exercised or has arisen against eating
ripe olives in the last year or two because of many deaths. I say many
—I suppose ten or fifteen altogether—just what an ordinary automobile
kills in Washington in a day, and nobody thinks anything about it,
and nobody stops riding in automobiles, but when one person out of
one hundred and five million dies from eating olives, everybody stops
eating olives. That is another indication of how wise humanity is.
We kill eleven thousand people in this country in a year with auto-
mobiles, and if ten people were to die of bubonic plague what a terrible
scare there would be all over this country! These men have gone into
this matter. First they looked over all the literature they could find,
and found that this organism was called botulism because it was first
found in sausage, and that was the Latin name for sausage. Cicero
never used it; they did not have any sausage in those days so far as I
know. We did not-stop eating sausage, but we did stop eating olives.
There are several remarkable things which are no longer secrets because
they were told publicly at a dinner given to me there where all these
men were invited to take part in the symposium. The best way to get
at what wes doing was to get each man to tell his story, and it was a
most interesting story, and he told it straight from the shoulder.
In the first place, this organism is probably as old, certainly as old as
that which produces the lockjaw or tetanus, and exists like the tetanus
germ in the soil; it is a soil organism. Of course, it is impossible to
sterilize the soil, especially in a State that is a thousand miles long and
three hundred miles wide; but they have found where the infected
spots are and they are very particular that all foods grown in that
region shall he subjected to the most careful scrutiny and sterilization in
234 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
order to make them perfectly safe for human consumption. They get
into everything that grows in the soil. There is a great deal more
botulism from green string beans than from olives, but green string
beans, when they are opened, seem to reveal their character much
better to the nostrils and, by the way, the odor of the toxin is the worst
odor you can imagine. I never smelled anything that begins to com-
pare in depravity with the odor of the poison produced by the Bacillus
botulinus. It is something to remember for a long, long while after
you get a whiff of it. But it does not appear in sound olives. They
found that the most unsatisfactory environment for the growth of the
organism is the olive in all stages, whether ripe or green, so long as it
was not decayed; and it only grows in an olive when the spores are still
stuck to the side of it, having come from the dust of the soil over which
they grow. It only develops in an olive when it becomes decayed.
Hence, if the canning is perfect, and the olive does not decay, the spore
never grows. The toxin is the most violent poison known. They told
me that if one cubic centimeter of the toxin were taken from the culture,
and diluted one hundred thousand times, one cubic centimeter of that
solution would kill a guinea pig, and hence one cubic centimeter of the
poison would kill one hundred thousand guinea pigs. That might be
of some service if it could be applied to rats and mice.
It is the most violent poison known but, at the same time, it is one of
the most easily destroyed, because a temperature of boiling water will
absolutely decompose this toxin and render it perfectly harmless. Hence,
a simple precaution, if you have any doubt about the matter, would
be to heat the suspected food to the temperature of 200 degrees or boil-
ing water, but even then you would not want to taste it if you got a
whiff of the material when heated. If such food is thrown out, it will
kill chickens, or pigs, or anything that eats it. Sometimes the organism
occurs in ensilage, in fodder and in hay that grows on this soil, and there
has been a tremendous fatality among horses and cattle that eat spoiled
ensilage and decayed fodder and hay from infected regions where botu-
lism is known to exist.
It was a surprise to me that no green olives are packed in California.
All of our green olives are imported; few imported ripe olives are used
in this country. Our ripe olives are from California. All the crop
not used for oil is put up as ripe olives in that State. The State Board
of Health has gone into each ripe olive factory, and has installed an
automatic register which runs for a week. It gives the actual tempera-
ture and the time in which the olives are kept in the sterilizer for every
process that is carried on during that week. At the end of the week
the agent of the Board of Health comes around and takes this record
out; he has the only key. He then puts in a new sheet for the next
week. In this way the State Board of Health has an automatic record
1921] WILEY: ADDRESS BY THE HONORARY PRESIDENT 235
of the length of treatment or sterilization, and the temperature of the
sterilization for every factory in the State. There are not many olive
factories in the State, but those that do exist are very large. I spent a
whole day in one of the largest factories in the State, going through
step by step, every process in which the olives were treated.
So now, they claim the product of California to be absolutely safe.
The thermal death point of the spore is about 240 degrees for forty
minutes. No spore has been able to grow which has been subjected
to that temperature for that length of time, and by this automatic
register they can see what has been done to every batch of olives which
is packed in California.
The scare because of the death of some ten or fifteen people in differ:
ent parts of this country paralyzed the whole industry. The crop of
the following year, that is, last year’s crop, is left still in the hands of
the packer. They are just beginning to move. The people are just
getting over this scare, and the assurance that this crop has been packed
with all these precautions will soon lift the ban and the business will
regain its former vigor. If you are the least bit careful, if you open a
can of ripe olives, and find a mushy one, throw the whole can away,
because it may possibly be infected. There is not a very great prob-
ability, but there is a possibility. The firm olive, the perfect olive, is
absolutely safe, and it is a splendid food and has a most delightful
flavor for people who once learn to eat it. It is a great business and
is now on a perfectly safe foundation.
All this has been done by chemical and bacteriological research.
Every step has been conducted by the union of these two sciences,
and the Bureau of Public Health, the Bureau of Chemistry and the
University of California, and the Leland Stanford Jr. University. The
National Canners Association advanced the money. It is a wonderful
thing to see the business men of this country so deeply interested, not
only in the financial part of their business alone, but in the excellence
of their product. That is one of the most hopeful signs that has grown
out of all the agitation which you and I have made in this country for
better food products, and all of this, my friends, has.grown out of your
work and the work which has been done in the last twenty-five or thirty
years to put the food products of this country on a higher plane and
the people who are making these food products begin now to appreciate
the work that has been done.
A short time ago I was standing at the Grand Central Station in
New York City and a gentleman in front of me, after buying his ticket,
said: “Are you Dr. Wiley?” I replied that I was. I did not know
what he was going to do with me, but I was ready to take the conse-
quences. He continued: “I am so glad to see you; give me your hand.
A few years ago I thought you were the devil incarnate; I am the Presi-
236 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
dent of the Long Island Oyster Growers’ Association, and when you
told us that we could not take oysters out of certain infected localities,
and could not ship them in the old way, soaking them in water and
packing in ice, we thought you were our bitter enemy and that you
were determined to destroy our business. If I had seen you then [
would have expected you to have horns and a long tail, I was so impressed
with the fact that you were the devil himself but you have done more
for our industry than any other man in the world. We are selling five
oysters now to one then, and we are sending oysters to all parts of the
country and they are just as good when they get there as when they
leave the water, all due to the fact that you dealt us what we thought
was a death blow to our industry.”
It has not been so many years ago that I was threatened to be mobbed
by the forerunner of the National Canners Association; they were
going to do me violence. I was invited to speak before that association
at Atlantic City and when the president met me at the station, I said:
“What is the matter? Are you ill?”” He looked like he had been eating
Atlantic fresh fish and ice cream. The fish came from Rhode Island,
and the ice cream was made last year, and when you put the two to-
gether it is pretty bad; once I ate some of it and I felt just like he looked.
“No,” he replied, “I am scared.”” Whereupon I asked him what was
the matter and was told that they were going to mob me. He advised
me to take the next train and go home. I had gone up there to make
a speech, and if I do not make a speech I am miserable, and if I do my
audience is miserable, so there you are; fifty-fifty. I continued: “Are
these men American citizens?” “Yes,” was the reply. “Are they
church members, and are they mostly republicans?” ‘‘Yes,” he an-
swered ““They are mostly republicans.” Then I said: “I do not believe
I will be afraid to face an audience of Americans who are church members
and republicans; I will take the risk. But is there a door at the back
of the stage?” He told me that he thought there was. I asked if it
were open and he promised to see that it was. He took me through
the back door, up the back stairs, and into his room, saying: “You do
not dare go into the lobby of this hotel; they will do you physical violence”.
There was a vast audience; men were standing, and did not look very
favorable from their countenances. <A great, big two-hundred pounder
stood by the door and when I went in said: ““We are not going to do a
thing to you”. I replied that I hoped not. The president was abso-
lutely afraid of physical violence because I had told these men that
they were putting out adulterated and misbranded foods, and they
had to quit it. That was before the Food and Drugs Act was passed,
and I had only moral force behind me. The president said: “You are
the first after luncheon, but the man who follows you is going to read
a long, prosy paper; let us put him in first’. I said I realized the power
1921] WILEY: ADDRESS BY THE HONORARY PRESIDENT 237
of personal pulchritude over an angry audience, and perhaps if I got up
there and let them look at me for half an hour they would not be so
cantankerous. So, they put him up and it was the shortest half-hour I
ever experienced. My time came quickly. I got up amid a deathly
silence. I speak a great deal and I am used to getting a little ap-
plause when I first get up; I hardly ever get any when I sit down, so I
appreciate that which comes first. There was absolutely the silence of
death in that vast audience, and I looked at them in my mild, benignant
way. I have a ministerial look, and have been taken for a minister of
the gospel. A few years ago, when I was young and handsomer and
wore a Prince Albert coat instead of this next year’s cut that I am
wearing now, I went to visit the Girard College in Philadelphia, and
the gatekeeper stopped me saying: ““You can not enter here; in Stephen
Girard’s will it is provided that no minister of the gospel shall ever
step inside of this enclosure”. I looked at him in my mild, benignant
way, and said: “The hell you say!” and was told to “Walk right in,
sir; walk right in’.
I looked at that audience in that same benignant spirit that I have
just described and began very gently: “If there is a man in this audience
who would put his hand in his neighbor’s pocket and take out a dollar
that does not belong to him and put it in his own pocket, stand up.”
Nobody stirred. And then I tried another tack on them. “Is there a
man in this audience who would so degrade a case of canned goods
that he puts up and so adulterate and misbrand them that he could
sell them for a dollar more than they are worth, and put that dollar in
his own pocket, will he stand up?” That is what every last mother’s
son of them had been doing, but not a single man stood up. And some-
one away back in the audience started a little applause, and it grew
and became a roar of approval. They were honest men; they were
American citizens; they were republicans as well as democrats, and
then—I say then,—I did not say now, but then they knew that they
were convicted and they recognized it. I went on and told them some
of their shortcomings that still had to be righted, and when I got through
sat down in a thundering applause, and the man who touched me on the
shoulder and said: ““We are not going to do a thing to you” arose. ‘“‘Mr.
President, I move a vote of thanks to Dr. Wiley for his most enthusiastic
and encouraging address.’ It was carried unanimously. That became
the National Canners Association that is doing this great work. That
is where they were convicted and converted. Why, St. Paul’s con-
version is not much better than that, and I had nothing to do with
converting St. Paul, I can assure you, but it was just as radical and
overwhelming, and since that day that association has followed that
lead, and today it is one of the most ethical associations, and doing
that splendid work, raising money and employing these experts, mary
238 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
of them former members of the Bureau of Chemistry. It is almost
like going to the Bureau of Chemistry to go around and visit these
establishments; boys, old boys, and new boys, boys that have come
into the Bureau since I left it, and have gone out into this great industry,
to do something for the food products of this country.
Gentlemen, I am glad to have had this opportunity to say a few
words about the progress you have made and the relations which exist
between this association today and at the time of its inception, and of
the wonderful future which is before you in all the varied industries of
this country. Not only food, but every other industry will seek and
demand your services in order that the industries may be put upon the
ethical basis of doing the best possible for those who consume the pro-
ducts of industry. Is not that a wonderful thing to think about? Is
it not wonderful to show the progress which has been made? (Pro-
longed applause.)
R. N. Brackett—I would like to move a rising vote of thanks to Dr.
Wiley for his address.
President Lythgoe.-—The chair is pleased to request a rising vote of
thanks to Dr. Wiley. (Prolonged applause.)
Dr. Wiley.—Thank you, Mr. President.
President Lythgoe.—We can go a long way before we can find a scientific
man who can get up and give us such an extemporaneous address.
ADDRESS BY THE SECRETARY OF AGRICULTURE—THE
HONORABLE E. T. MEREDITH.
I feel that Dr. Alsberg owes this group an apology for inflicting me
upon you, but it is a pleasure to me and a privilege to run in for a moment
and assure you of my personal appreciation and the appreciation of the
Department of Agriculture of the value of the work you are doing.
There is no question that today research work along all lines has come
to be more fully appreciated and valued by the people generally. There
are many things that have brought this about. The world war has
added to our knowledge of what may be accomplished in the way of
research. The advancement that has been made in the study of foods,
the study of fertilizers, and many other lines has added to that. It
was not so long ago, as I am sure you appreciate, that many of the
research men and the scientists were referred to quite generally as
“long-haired scientists’. I have heard the reference many, many
times when in contact with agricultural groups and others. I do not
see any here who would qualify as long-haired scientists, but such
comment is passing now, and I feel that I may say to you earnestly
and sincerely that there is no group of workers in the country whose
1921] MEREDITH: ADDRESS BY THE SECRETARY OF AGRICULTURE 239
work is more fully valued and appreciated than that of the research
workers. It has been my privilege during the past few months to
emphasize this work somewhat and in talking with groups of farmers I
have emphasized research and the value of the work of the scientist.
I have asked farmers if they believed in the rotation of crops, and they
have said, of course they believed in the rotation of crops; and then I
have asked them who told them what a crop, a particular crop might
need in the way of plant food; who told them what elements of the soil
went to make certain crops; who named the elements of the soil, and
so on. And they came to see that the rotation of crops was really
based upon the research work of the scientist, the analysis not only of
the soil, but of the crop; and then I have asked them if they believed
in balanced rations for their live stock, and in every case they said:
“Why, certainly, we practice balanced feeding; that is practical agri-
culture”. And then when you ask them what elements go to make
milk, what elements go to make beef, and who named those elements
in the feed, and who named the elements in the product, then they
appreciate that it was a scientist again, a man who had analyzed,
who had studied, and they come to believe and to appreciate that it is
all based in the final analysis upon scientific study and research work.
So I feel that you may be perfectly satisfied and take great pride in
the fact that the value of this work is becoming more and more generally
appreciated and its relations to all our activities, not alone in agriculture,
to which you men and women are deyoting your particular studies,
but to all lines of endeavor recognized.
We are finding in the Department of Agriculture that this is true in
another way than simply expression of appreciation on the part of the
people generally, but in the fact that large commercial organizations
are constantly calling upon the Department for men, offering them
more attractive salaries than we have been privileged so far to offer,
and taking them away from the Department to devote their time and
energies to particular institutions to the credit and the advantage of
these institutions. So to you who are doing this great work, I at least
want to say for myself, that I feel you are doing a public service, and
that you are to be most heartily commended. ‘I feel, too, that the
material advantages should be largely increased to those who are doing
this worth-while work in the study of foods, the study of all the things
that go for our material comfort and our health. That means better
salaries. This would mean more opportunity for the young men and
would attract more young people to this line of work. I hope that
through our efforts, particularly with Congress, there will be greater
attractions in the Government service along this line in the future
than there have been in the past.
240 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
You in your particular line of work have accomplished much in the
methods of analysis and examination, but I am sure you understand,
and that I may be privileged to say, that there is still much to be done,
and that those young in the work and your members who are young
in years, will have just as many opportunities for real accomplishment
and will find just as many responsibilities as those who are older in the
work and have carried the burdens up to this point. There is much in
the study of foods, in our fabrics, in our fertilizers and other lines to be
done, and certainly the members of this organization must play a great
part in that work. I wish to congratulate you and commend you most
heartily for what you have done, and wish for you still greater accom-
plishments in the future. I thank you.
The meeting adjourned at 12:45 p. m. to reconvene at 2 p. m.
SECOND DAY.
TUESDAY—AFTERNOON SESSION.
REPORT ON CEREAL FOODS.
By C. H. Barey (Agricultural Experiment Station, University Farm,
: St. Paul, Minn.), Referee.
The referee received his appointment, and necessary reports and
other data too late to make possible the completion of the desired col-
laborative work. Moreover, at the time of the receipt of this material only
one collaborator had signified a willingness to assist in this work, and
considerable time was consumed in correspondence with prospective
collaborators. A half dozen chemists have agreed to collaborate, out-
lines for work in accordance with the recommendations of Committee
C' have been drawn up, and samples are being prepared and distributed
to the collaborators.
The American Institute of Baking has, during the past few months,
conducted a study of methods employed in the analysis of flour, to
determine how nearly a number of chemists checked one another when
analyzing the same material. Three samples, marked A, B, and C,
were sent to each of the collaboratoring chemists in rubber-stoppered
bottles, with the request that the percentage of moisture, ash, crude
protein, and crude gluten be determined by the method usually employed
in their respective laboratories. ‘The American Institute of Baking has
kindly furnished tabulated statements of the several reports, which are
worthy of careful scrutiny.
In the case of moisture determinations, so far as the referee can dis-
cern from the reports, only 12 of the 28 chemists who reported are
employing the official method, which provides for drying to constant
weight in vacuo or hydrogen. The other 16 are apparently using air
ovens heated in a variety of ways. In more than half of the cases where
air ovens were used the temperature was maintained appreciably above
100°C., namely, from 103° to 105°C.
In Table 1 are given the maximum, minimum, and average moisture
percentages as determined by the official vacuum oven method, and by
drying in air ovens. The single report on drying in hydrogen is not
included in this summary. These data show: Ist, somewhat higher
averages where the vacuum oven was used; and 2nd, a tendency towards
smaller deviations from the mean when the results by the use of the
J. Assoc. Official Agr. Chemists, 1921, 4: 577.
241
242 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
vacuum oven are compared with those obtained by drying in contact
with the air. This tendency is emphasized still further by omitting
from the series of Samples C, which was dried in vacuo, the report of
10.73 per cent, which is distinctly out of line with the other reports on
these samples. This omission would reduce the range from maximum
to minimum in the samples of flour C dried in vacuo to 1.27 per cent
instead of 2.61 per cent as shown in Table 1.
TABLE 1.
Determination of moisture in flour samples.
METHOD SAMPLE A SAMPLE B SAMPLE C
Dried in vacuo per cent per cent per cent
Maximum 12.83 11.16 13.34
Minimum 11.76 10.25 10.73
Average 12.37 10.88 12.81
Dried in air ovens
Maximum 12.80 11.50 13.59
Minimum 10.70 9.03 11.08
Average 11.93 10.53 12.53
These results seem to emphasize the desirability of adhering to a
standard procedure in the determination of moisture, and to the elimina-
tion of the air oven in favor of the vacuum oven.
Ash was determined in each of the three flour samples by the same
28 chemists. Table 2 gives a summary of their reports. While a
fairly wide range is shown in the percentage of ash as determined by
different chemists, by scanning the individual reports it is seen that in
26 out of 28 reports on Sample A there was a deviation of 0.02 per cent
or less from the mean, and in 25 out of 28 reports on Samples B and C
the deviation from the respective means was no greater. Three of the
analysts reported the use of calcium acetate in the incineration of the
flour. The averages of these three determinations were: Sample A,
0.445 per cent; Sample B, 0.380 per cent; and Sample C, 0.693 per
cent. There appeared, accordingly, a slight tendency towards higher
results by the use of calcium acetate in the determination of ash.
TABLE 2.
Determination of ash in flour samples.
DETERMINATION SAMPLE A SAMPLE B SAMPLE c
per cent per cent per cent
Maximum 0.470 0.390 0.730
Minimum 0.403 0.324 0.670
Average 0.427 0.350 0.696
1921] BAILEY: REPORT ON CEREAL FOODS 243
Protein determinations were made in all cases by the Kjeldahl method
or one of its modifications. The results show some wide variations due,
apparently, to various causes. At a recent meeting of cereal chemists
it seemed to be the consensus of opinion that where several analysts
failed to obtain the same results in the determination of crude protein,
errors were to be attributed generally to inaccurate standardization of
the acid solutions used in titration. That this is not the sole cause of
variations in the reports on these three samples is to be deduced from
the fact that the analyst who reported the lowest percentage of crude
protein in Sample A also reported the highest percentage in Sample B.
TABLE 3.
Determination of crude prviein in flour sampies.
DETERMINATION SAMPLE A SAMPLE B SAMPLE C
per cent per cent per cen
Maximum 13.10 10.00 12.84
Minimum 11.48 8.31 11.28
Average 12.14 9.21 11.97
To ascertain whether the standard acid used by the several analysts
varied sufficiently to account for the differences in the results reported,
the data were divided into two groups. The basis of division was the
percentage of crude protein reported in Sample A. In all instances
where the analyst reported less than the average percentage of protein,
his data were averaged by samples and constituted the first group.
Where the percentages of protein reported in Sample A were greater
than the average, the data for all three samples were grouped by sam-
ples, and constituted the second group. In Table 4 the averages of the
groups divided in this manner are shown. These averages indicate that
the analysts who reported higher percentages in Sample A also reported,
on the average, higher percentages in Samples B and C, although the
results are not in direct ratio. Moreover, there are individual excep-
tions to the general rule. It may be concluded that while errors in
' standardizing the acid used in titration are probably responsible for
certain of the deviations shown, other errors occur at the same time.
TABLE 4.
Average group determination of protein.
|
GROUP DETERMINATION SAMPLE A SAMPLE B SAMPLE C
per cent per cent per cent
Where protein reported in Sample A exceeded
the average 11.85 9.03 11.86
Where protein reported in Sample A was less
than the average 12.39 9.37 12.09
244 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
The results of the determination of crude gluten by 21 analysts varied
more than did the determination of crude protein. This is doubtless
to be expected, in view of the character of the method. In Table 5
are shown the maximum, minimum, and average percentage of crude
gluten reported by 21 analysts. It is interesting to note that in the
case of the two flours of fairly high gluten content the average percentage
of crude gluten, and of crude protein (chemically determined) are
almost identical. In the case of Sample B, which contained a low
percentage of gluten, the average crude gluten was appreciably less
than the average crude protein.
TABLE 5.
Determination of gluten in flour samples.
DETERMINATION SAMPLE A SAMPLE B SAMPLE G
per cent per cent per cent
Maximum 13.50 10.60 13.00
Minimum 9.80 5.90 10.00
Average 12.00 8.65 12.06
This work, which was conducted by the American Institute of Baking,
is of significance in that it emphasizes the necessity of uniformity in
procedure, and also indicates the relative deviation from the means
which may be anticipated when determinations are made by a number
of analysts.
The referee regrets that another organization has undertaken to
promulgate standard methods for the analysis of cereal products.
Where the official or tentative methods of this association are thus
prescribed no particular harm is done, and neither does any advantage
accrue. The promulgation of other than official methods of this asso-
ciation by an association of chemists seems regrettable, however, and
something to be avoided.
RECOMMENDATION.
The referee recommends that work now in progress, recommended
by Committee C in 1919!, be continued.
No referee on the subject of distilled liquors was appointed and no
report on this subject was presented.
No referee on the subject of wines was appointed and no report on
this subject was presented.
No report on the limit of accuracy in the determination of alcohol in
beers was made by the referee.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 577.
1921] BALCOM: A NOTE ON THE POLARIZATION OF VINEGARS 245
No referee on methods of analysis of near beers was appointed and
no report on this subject was presented.
No general report on vinegars was made by the referee.
A NOTE ON THE POLARIZATION OF VINEGARS.
By R. W. Batcom and E. Yanovsky! (Bureau of Chemistry,
Washington, D. C.).
In dry cider and in cider vinegar there are usually at least three
optically active substances present, namely, sugar (levulose), malic
acid, and lactic acid?. If the fermentations have been normal the
rotation of cider and of cider vinegar is never plus, so far as is known,
although it may approach zero as a limiting value from the negative
side. Abnormal or unusual fermentations sometimes, though rarely,
occur. An instance of such fermentation in a cider was observed in
1910 by the Bureau of Chemistry when, in the course of its regulatory
work, a sample of cider was collected which, upon analysis, was found
to be dextrorotatory. Further investigation showed that it was a
genuine product in which the levulose had been fermented out before
the dextrose, instead of the dextrose before the levulose as is ordinarily
the case. The usual procedure in determining the polarization has
been to clarify with solutions of neutral lead acetate or of basic lead
acetate and polarize without the removal of lead from the filtrate. The
directions given in the methods of this association call for the use of
basic lead acetate supplemented, when necessary, with alumina cream.
In 1912 Bender* reported having found a plus polarization of 0.7°V.
for a sample of cider vinegar when this vinegar was clarified with lead
subacetate in the usual way. The vinegar in question had been manu-
factured in his presence so that there was no question as to its authen-
ticity. It contained an unusually large quantity of nonvolatile acid,
0.32 gram per 100 cc., calculated as malic acid. The same vinegar,
when treated with bone black alone, gave a negative polarization of
0.44°V. Bender concluded that this anomaly might be due to the effect
of lead salts in solution. His experiments with malic acid and lead
subacetate confirmed this assumption and in his recommendations as
referee he suggested a study of the method used for determining polar-
ization.
In 1915 asample of vinegar found on the market labeled as apple
vinegar was examined by the Philadelphia Food and Drug Inspection
Station of the Bureau of Chemistry. The analytical results obtained
1 Present address, Norwalk Tire and Rubber Co., Norwalk, Conn.
2 J. Ind. Eng. Chem., 1917, 9: 759.
3 U.S. Bur. Chem. Bull. 162: (1913), 81.
246 ASSOCJATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
were normal for a cider vinegar except that like the Bender sample its
nonvolatile acid content was high (0.31 gram per 100 cc.) and it gave
a plus polarization of 0.56°V. This sample when further examined
in the Food Investigation Laboratory of the Bureau of Chemistry, by
treating with 10 per cent by volume of the reagents named, gave the
results shown below. ‘The rotation in each case is the average of three
readings calculated to the undiluted basis:
Basic lead acetate (official)
(a) Lead not removed from filtrate.................. +0.7°V.
(b)} Ibead'removyed!. 4527-0224 Sics Ae. Ses Pasa -0.6
Neutral lead acetate (solution containing 20 grams per 100 cc.)
(a) Lead not removed from filtrate.................. +0.3
(b) ead removed! en scceu ricci eee 0.7
Aluminarcreammalonesscne acct ce ee nie erate -0.6
More recently, having had on hand some partly fermented apple
juice with a nonvolatile acid content of 0.28 gram per 100 cc., the authors
repeated Bender’s experiments to see whether the same phenomenon
would be observed with cider and, if so, whether it could be explained
in the same way. The principal difference, of course, between the
partly fermented juice and vinegar is that in the partly fermented juice
there is more sugar and less acid present. This cider, when clarified
with 10 per cent by volume of neutral lead acetate (solution containing
20 grams per 100 cc.) gave a reading of —3.2°V.; with the same volume
of basic lead acetate (official), a reading of —3.5°V. When lead was
removed from the filtrate both solutions gave a reading of —4.2°V.
Thus there was observed the same shifting of the rotation as was noted
with the vinegars previously mentioned.
Some observations were next made on the behavior of pure malic
acid. Portions of a solution of malic acid which showed a rotation of
—0.8°V. were treated with neutral lead acetate and basic lead acetate
and these solutions then gave a reading of +1.1°V and +2.2°V., respec-
tively. In the latter case, however, a considerable quantity of acetic
acid was added to prevent precipitation. It was found that 5 to 6 per
cent of acetic acid, the approximate quantity in a vinegar, was sufficient
for this purpose. Bender’s observations as to the behavior of malic acid
under similar conditions were therefore confirmed.
The following experiments show, however, that in the case of ciders
at least, on account of their low acidity as compared with that of vinegar,
part of the nonvolatile acid is precipitated on the addition of both
neutral and basic lead acetates. Portions of this cider, which con-
tained 0.28 gram per 100 ce. of nonvolatile acid, were clarified with
neutral and basic lead acetates and the lead subsequently removed
from the filtrate with hydrogen sulfide. That portion clarified with
neutral lead acetate then showed a nonvolatile acid content of 0.13
1921] BALCOM: A NOTE ON THE POLARIZATION OF VINEGARS 247
gram and the portion clarified with basic lead acetate a nonvolatile
acid content of 0.09 gram per 100 ce.
The effect of fructose (levulose) is shown by the following experiment.
A solution of fructose, which read —12.0°V., after the addition of neutral
lead acetate read —-11.9°V., and after the addition of basic lead acetate,
-9.5°V.
When lead salts are used for clarification or decolorization the lactic
acid present may also contribute to this shifting of rotation. A solu-
tion of lactic acid which showed a rotation of +3.9°V., on addition of
neutral and basic lead acetates showed a rotation of +5.2°V. and
+6.2°V., respectively. When the same experiment was repeated in
5 per cent acetic acid solution the rotations were +4.4°V. and +5.4°V.,
respectively.
The fact that the use of basic lead acetate is not permissible for the
clarification of solutions containing levulose, when sugar is to be de-
termined, is well known. It has also been known for some time that
different salts have considerable effect upon the rotation of malic acid}.
Dunbar and Bacon! in their work on the determination of malic acid
showed the necessity of removing lead before polariscopic readings
were made.
It is apparent from the foregoing discussion that the use of lead salts
for the clarification of cider vinegar preliminary to polarization, particu-
larly if lead is not removed from the filtrate, may lead to entirely mis-
leading results. Since the principal, if not the only, use made of the
polarization value of a cider vinegar, or, for that matter, of any vinegar,
is as a criterion of purity, it is not apparent why clarification in the
sense of removing other optically active substances than sugar should
be necessary at all. What is wanted is the polarization value of the
product under examination containing, in the case of genuine products,
all of the substances, both in kind and quantity, which are normally
present. This undoubtedly is what is meant by Bender when he used
the term “true polarization” in his 1912 report. The ideal for this
purpose would be the polarization value of the product without any
treatment whatever. Such preliminary treatment as may be necessary
with colored or turbid vinegars should be for the sole purpose of re-
moving the turbidity and as much of the color as may be necessary to
obtain a reading. For a number of years the Food Investigation Lab-
oratory has been using “‘‘eponite’ or “‘norit’” for this purpose with
entirely satisfactory results. It is believed that the method now pre-
scribed by the association should be dropped and a method based upon
the principles outlined in this paper adopted. The use of “‘eponite’’,
“norit”’ or other similar decolorizing charcoals is recommended.
1J. Ind. Eng. Chem., 1911, 3: 563; Ibid., 826.
248 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
No report on flavoring extracts was made by the referee.
No report on meat and meat products was made by the referee.
No report on the separation of meat proteins was made by the asso-
ciate referee.
No associate referee on the subject of the decomposition of meat
products was appointed and no report on this subject was presented.
No report on gelatin was made by the associate referee.
No report on spices was made by the referee.
SALAD DRESSINGS AND THEIR ANALYSIS.
By H. A. Lepper (Bureau of Chemistry, Washington, D. C.).
The term “salad dressing” is a familiar one in probably every house-
hold yet these products have received little attention from food officials
judging from recorded writings. In fact, no references to analyses of
such products could be found in the literature. No standards for
salad or mayonnaise dressings have been issued. Recipes and definitions
given in cook books and dictionaries show the term “salad dressing” to
be more general than ‘‘mayonnaise’’ which appears to be well under-
stood as applying to a product made from egg yolk, a food oil and condi-
ments. No recipe was found which called for the use of flour, gum,
gelatin, starch or turmeric in mayonnaise dressing.
No systematic outline of methods for the analysis of salad dressings
was to be found in the usual works on foods or food analysis. The
following methods, therefore, were worked out for the analysis of these
products:
PREPARATION OF SAMPLE.
Mix the product until it is thoroughly homogeneous before sampling. This is
especially necessary if the sample has stood for any appreciable time. Use approxi-
mately the quantity directed for the various determinations, noting accurately the
actual weight. The weighing may be conveniently done from a Bailey weighing buret'.
TOTAL SOLIDS.
Weigh 10 grams of the sample into a tared lead dish (bottle cap) having a diameter
of about 24 inches and containing 10-15 grams of clean dry quartz sand. Evaporate
on the steam bath to apparent dryness and then dry to constant weight in a vacuum
Cool in a desiccator and weigh. Weigh-
oven at the temperature of boiling water.
(Reserve the dry
ings on samples high in solids should be made at 1-hour intervals.
material for the determination of lecithin-phosphoric acid.)
1C. A., 1916, 10: 3003.
1921] LEPPER: SALAD DRESSINGS AND THEIR ANALYSIS 249
ASH- AND CHLORINE.
After drying 2 grams of the sample on the steam bath, determine the ash! and
chlorine’.
REDUCING SUGARS BEFORE AND AFTER INVERSION.
Extract the oil from 20 grams of the sample in a wide-mouthed, 4-ounce bottle, by
adding about 80 cc. of petroleum ether, shaking, and centrifugalizing. Draw off as
much as possible of the petroleum ether solution (using suction and a short-stemmed
pipet) and repeat the treatment with petroleum ether until all of the oil has been re-
moved, as indicated by the absence of color in the solvent. Usually about four extrac-
tions are required.
Remove the petroleum ether from the residue with a current of air and transfer
the residue with water to a 100 cc. graduated flask. Add 5-10 cc. of a fresh solution
of metaphosphoric acid (prepared by dissolving 5 grams of the transparent lumps or
sticks in cold water and making up to 100 cc.), mix thoroughly, make up to volume,
and filter. Transfer 80 cc. of the filtrate, or as large an aliquot portion as possible,
to a 100 cc. flask and, after neutralizing with a strong solution of sodium hydroxide,
using phenolphthalein as indicator, cooling, and making up to the mark with water,
determine the reducing sugar before inversion on an aliquot sample by the Munson
and Walker method.
Invert another aliquot portion and determine the reducing sugar after inversion by
the same method. Calculate as invert sugar in both cases.
Note.—Some dressings, particularly those containing starch, can not be clarified
in this manner. It is then necessary to use the alcohol method for sugars’. When
this method is used the residue from the petroleum ether extraction should be trans-
ferred to a 300 cc. flask with the 50% alcohol.
SUCROSE.
Calculate the sucrose from the difference between the reducing sugar after inversion
and before inversion.
TOTAL ACID.
Titrate 10 grams of the sample in 400-500 cc. of recently boiled and cooled water
with standard alkali, using phenolphthalein as indicator. Calculate as acetic acid.
VOLATILE ACID.
Determine volatile acid on a 5-gram portion‘.
NITROGEN. x
Use 2-3 grams of the sample and determine nitrogen by the Kjeldahl-Gunning-
Arnold method‘.
OIL.
Determine the oil by the Roese-Gottlieb method® on 2 grams of the sample, using
2 ce. of concentrated ammonium hydroxide, 10 cc. of alcohol, and enough water to
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 71.
2 Ibid , 19.
3 Tbid., 94.
4 Ibid., 177, 25.
5 Ibid., 7.
* Tbid., 227.
250 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
fill the tube to just below the outlet, and making at least four extractions. Dry the
oil in a vacuum oven at 70°C. to constant weight. (The residue remaining in the
tube may be used for the turmeric test.)
LECITHIN-PHOSPHORIC ACID.
Transfer the residue obtained in the determination of total solids to an extraction
thimble adding also the lead dish which has been cut into pieces. Extract with abso-
lute alcohol in an extractor of the siphon type in which the vapor heats the contents
of the siphon thimble. After 10 hours’ extraction, saponify the extract with alcoholic
potassium hydroxide (for each gram of fat present use 5 cc. of a solution containing
8 grams of potassium hydroxide per 100 cc.) in a beaker or large platinum dish.
Evaporate to dryness and ignite. Extract the charred mass with dilute nitric acid
and filter. Return the paper to a dish and ignite to a white ash; dissolve in dilute
nitric acid, filter and wash. Determine phosphoric acid in the united filtrates in the
usual manner.
STARCH.
Qualitative and quantitative determinations may be made by the methods given
for meat products'.
GUMS.
Existing methods were found to be helpful in the identification of gums?.
BENZOIC ACID.
To determine benzoic acid or sodium benzoate, make 50 grams of the sample alkaline
with strong sodium hydroxide. Extract the oil by shaking with petroleum ether.
After the oil or fat is removed transfer the residue to a large evaporating dish and heat
on the steam bath to coagulate the egg solids, adding alcohol to the extent of one-
third the volume of the solution, if necessary. Transfer to a 300 cc. flask, saturate
with salt, make up to the mark with saturated salt solution and filter. Extract benzoic
acid from an aliquot portion of the filtrate and proceed as directed in the official quanti-
tative method?.
TURMERIC.
Acidify with hydrochloric acid the residue remaining in the Roese-Gottlieb tube
after the extraction of the oil and apply the filter paper boric acid test*.
ARTIFICIAL COLOR.
Make a portion of the sample alkaline with ammonium hydroxide and extract with
petroleum ether. Test the extract if colored for oil-soluble colors, and the residue
for other colors®.
No attempt was made to identify the oil used. However, the residue obtained by
evaporating the petroleum ether used to extract the oil in the sugar determination
can be used for this purpose and the identity of the oil established by the usual chem-
ical and physical tests.
1 Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 212.
2 J. Ind. Eng. Chem., 1918, 10: 530; J. Am. Pharm. Assoc., 1920, 9: 31.
3 Assoc. Official Agr. Chemists, Methods. 2nd. ed., 1920, 120.
* Ibid., 144
5 Thid., 131.
1921] LEPPER: SALAD DRESSINGS AND THEIR ANALYSIS 251
A sample of mayonnaise was made in the laboratory from a typical
recipe, as shown in Table 1. The results of the analysis of this sample
and 10 others bought in the open market are given in Table 2.
Besides the result reported in the table for sucrose in the laboratory
sample by the metaphosphoric acid method, a determination by the
alcohol method for sugars was made and 0.07 per cent of invert sugar
before inversion, 0.57 per cent of invert sugar after inversion and 0.48
per cent of sucrose was found. Sodium benzoate was added in the
proportion of 0.05 gram to 50 grams of mayonnaise (0.1 percent) and
0.055 gram or 0.11 per cent was found by the above method for benzoic
acid. Juckenack! gives values for the lecithin-phosphoric acid content
of eggs, stating that an average-sized egg yolk of 16 grams contains
0.1316 gram, or 0.82 per cent of lecithin-phosphoric acid. Calculation
based upon these figures and the 0.107 per cent of lecithin-phosphoric
acid found in the laboratory sample indicate the presence of about
13.0 per cent of egg yolk. This value does not agree very well with the
7.06 per cent actually used. While the percentage of lecithin-phosphoric
acid, as determined by this method, may serve as an indication of the
relative amounts of egg yolk in different samples, it is evident that
more work must be done before these percentages can be used for more
than a rough approximation of the actual quantity of egg yolk preseni.
TABLE 1.
Composition of sample of mayonnaise prepared in the laboratory.
INGREDIENTS WEIGHT PERCENTAGE
grams.
Olive oil 487 79.37
Vinegar (cider) 70 11.41
Sugar 2.99 0.49
Salt 6.64 1.08
Mustard 3.60 0.59
Two egg yolks 43.34 7.06
TNE a ona8 oe eer 613.6 100.0
The results show that the dressings on the market are of varying
composition. The use of starch in two samples and gum tragacanth in
one labeled as “mayonnaise” is shown. Judging from the well-under-
stood meaning of the term “mayonnaise” the presence of these materials
is an adulteration. Moreover, it can be noticed that in the sample
containing 6.94 per cent of oil where gum tragacanth was found to be
present there is a marked deficiency in oil content. This is also true of
the samples containing starch. This would indicate a concealment of
inferiority by the use of starch or gum. In one sample where starch is
1Z, Nahr. Genussm., 1900, 3: 11.
252 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
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1921) TABER: DETERMINATION OF SHELLS IN CACAO PRODUCTS 253
used, the oil content was found to be 36.48 per cent which is low but
not excessively so. Another sample, sold as salad dressing, was labeled,
in part, “Ingredients sugar, cereal, salt, mustard, egg, vinegar, oil,
certified color”. It may be noticed in this case that the use of cereal
has allowed as little as 3.34 per cent of oil to be used. This sample
was not labeled ‘mayonnaise’ and the presence of cereal was declared.
Naphthol Yellow S was detected in this sample. All the samples were
tested for turmeric and benzoic acid with negative results.
It is recognized that the methods herein suggested are open to improve-
ment and that there is much opportunity for further work on the analysis
of salad dressings.
REPORT ON THE DETERMINATION OF SHELLS IN CACAO
PRODUCTS.
By W. C. Taser! (U.S. Food and Drug Inspection Station, Park Avenue
Building, Baltimore, Md.), Referee.
The shell of the cocoa bean amounts to about 11 to 13 per cent of the
total weight of the bean. The greater part of this shell is removed
from the bean in the process of manufacture of chocolate goods, but
there always remains a small residuum which it is impossible to separate
from the nibs by any factory machinery. This small residue of shells
in the nibs may be increased by faulty operation in the factory, either
purposely or through careless management. Shells also may be added
to the liquor by the deliberate addition of the ‘“‘fines’’ which is the
finest particles of nibs and shells that come from the fanning machine
and usually is about one-half shell. The estimation of these excessive
amounts is the problem of the inspection chemist.
Many different physical and chemical methods have been proposed
for the determination of shell, particularly by the German chemisis.
Of the former methods that of Filsinger? by a sedimentation process,
that of Macara’, and that of Goske* of flotation in calcium chloride
solution, have all been tried by various investigators and found lack-
ing. The variations in the fineness of grinding and in,the specific gravity
of the shell particles are serious defects in the quantitative results of
these processes.
Of the chemical methods which have been suggested in recent years.
the determination of pentosans was emphasized by Adan®; the determi-
nation of cocoa red, which Ulrich®, the author, states will show only
1 Present address, U. S. Food and Drug Inspection Station, Federal Building, Buffalo, N. Y.
2Z. offent. Chem., 1899. 5: 27
2E. R. Bolton and Cecil Revis. Fatty Foods. Their Practical Examination. A Handbook for the
Use of Analytical and Technical Chemists. 304.
4 Analyst, 1910, 33: 162.
5 Seventh Intern. Cong. Appl. Chem., 1909, VIII C: 194.
* Arch. Pharm., 1911, 249: 524.
254 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
10 per cent or more of shells; more recently Keller! proposes the color of
the ether extract as a method, that from shell being darker than extract
from the nibs. A very good resumé of these and other methods has
been given by Ulrich and also by Knapp and McLellan’.
Beythien and Pannwitz’ state that the total and water-soluble phos-
phoric acid are means of determining the amount of shells present.
They conclude, however, as do Knapp and McLellan and other investi-
gators, that the crude fiber is the most important single determination
that can be made. Since this has been so generally agreed upon, it is
well to look at the data available on the crude fiber determination to
see what results may be expected.
Consideration first must be given to the fact that clean nibs free from
shells give a certain figure for the crude fiber, varying with the different
varieties of the beans, the temperature of the roasting, the fineness of
the grinding and, Knapp and McLellan state, with the ripeness of the
bean and the degree of fermentation. The soft pulp that surrounds
the bean is decomposed by fermentation, and so runs off from the mass
of beans as a liquor. If the fermentation is not carried sufficiently far
some of this pulp remains and hardens on the beans so that it can not
be separated from the shell. Data obtained in the Bureau of Chemistry
by B. H. Silberberg and the referee show that sometimes this dry pulp
remaining on the beans increases the apparent weight of the shell by
2 per cent or more.
The following table shows the maximum, minimum and average
figures obtained for crude fiber by various investigators, both in the
clean nibs and on the shells from various varieties of beans.
TABLE 1,
Crude fiber on dry fat-free material.
INVESTIGATOR ROASTED NIB AVERAGE ROASTED SHELL AVERAGE
per cent per cent per cent per cent
Booth, Cribb and Richards* 4.7—6.2 ses 13.2—16.3 “ate
Winton, Silverman and Bailey t+ 4.7—6.6 5.6f 13.7—20.7 18.0t
Knapp and McLellan§ 4.6—6.8 5.8** 15.4—21.4 18.7**
Bureau of Chemistry {+ 5.5—7.7 6.2f 14.7—24.4 18.6ff
W. C. Taber and M. L. Of-
futt§§ 5.9—7.5 Gon 14.8—23.9 1827555
* Analyst, 1909, 34: 134.
{ Rept. Conn. Agr. Exp. Sta. 1902, 248.
t Average results of analyses of 17 varieties of beans.
§ Analyst, 1919, 44: 2.
“* Average of 10 determinations of 8 varieties of beans.
+} U.S. Bur. Chem. Information from Eugene Bloomberg and W. C. Taber.
tt Average of 21 determinations of 21 varieties of beans.
§§ Unpublished, 1920 data.
© Average of 12 determinations of 7 varieties of beans.
1 Arch. Pharm., 1917, 255: 405.
* Analyst, 1919, 44: 2.
3 Z. Nahr Genussm., 1916, 31: 265.
1921] TABER: DETERMINATION OF SHELLS IN CACAO PRODUCTS 255
It is interesting to note in Table 1 the quite close agreement obtained
by the different workers in recent years, the average being in especially
close agreement. It is worthy of note, however, that the analysts in
the Bureau of Chemistry have obtained somewhat greater extremes of
crude fiber both in the case of the nibs and also of the shells. This may
be due in part to the kind of beans used recently. It has come to the
writer’s attention that about one-half of the beans imported into this
country are of the Accra variety. From Table 2 it is seen that the fiber
on- the Accra nibs and shells runs higher than most other varieties.
This seems to be particularly apparent in the figures for shells.
Table 2 gives in detail the figures by Taber and Offutt quoted under
Table 1.
TABLE 2.
Crude fiber on moisture and fat-free basis.
VARIETY OF BEAN NIBS SHELLS
per cent per cent
Accra 7.47 22.77
Accra 6.76 23.90
Arriba 6.85 17.33
Bahia 6.14 20.18
Bahia 5.97 18.93
Caracas 5.82 16.82
Caracas 6.88 15.22
Sanchez 6.22 18.62
Sanchez 5.87 19.71
Trinidad TAS 16.64
Trinidad 5.88 14.79
Machala 7.44 20.05
IANEEAQEY pric). ce 6.54 18.74
These figures represent beans obtained during the summer of 1919
by B. H. Silberberg and the writer at different chocolate factories in
the east, and roasted in the laboratory at a temperature of 140°C.
The figures verify the statement previously made that even the same
variety of bean may vary in the fiber content on account of the degree
of ripeness, and other factors.
In the information card by Eugene Bloomberg and the writer, cited
in Table 1, it was stated that since the crude fiber on only one sample
of beans ran above 7 per cent, it seemed safe to assume that figure as a
maximum for the purpose of calculating the amount of shell present
in any chocolate sample. It will be noted from Table 3, however, that
three varieties ran somewhat above 7 per cent, and one of them was a
variety largely used. It is possible, therefore, that further investigation
will warrant raising this maximum figure somewhat.
From Table 1 it would appear that the figure for fiber in shells might
well be taken at about 19 per cent for the purpose of calculating the
256 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
results. This would indicate that an increase of 1 per cent in fiber
above the standard for the nibs would mean an increase of shell con-
tent of approximately 8 per cent. In order to determine how closely
this calculation could be applied, mixtures of defatted ground shell and
nibs passing through a 100-mesh sieve were prepared in different pro-
portions and crude fiber determined on this mixture. The results are
given in Table 3.
TABLE 3.
Crude fiber on mizture of defatted ground shell and nibs.
(Analyst, M. L. Offutt.)
SAMPLE NUMBER SHELL PRESENT CRUDE FIBER FOUND
per cent per cent
1 2.50 4.60
2 3.50 6.77
3 4.00 8.08
4 4.80 7.38
5 6.00 7.26
6 6.00 8.70
a 6.50 8.85
8 7.00 9.25
9 7.00 9.01
It should be stated in connection with Table 3 that Samples 2, 3,
5, 8 and 9 were composed of the same varieties of nibs and shells, and
were different from the varieties found in the other samples. This
would account for some of the differences that are apparent, for instance
in Nos. 5 and 6, with the same amount of shell but with quite large
variation in fiber. The fiber content in Nos. 6, 7, 8 and 9 would indi-
cate a much larger percentage of shells than is actually present if the
figures for nibs and shells indicated above are used. ‘This is in accord-
ance with the experience of Knapp and McLellan who would deduct
8 per cent from the shell content, as found by the fiber method, in order
to determine the actual amount present. It is apparent that in the
samples just referred to this would give a close approximation to correct
results. It is also evident from Table 3 that the detection of small
amounts of shells is impossible by the crude fiber method. It apparently
is necessary to have about 4 per cent of shells in the sample before
excessive amounts of fiber are indicated.
This also can be made clear from mathematical consideration. Taking
a mixture of 5 per cent of shells with a fiber content of 18.7 per cent,
and nibs with a fiber content of 6.5 per cent, the resultant mixture
would yield a fiber content of 7.1 per cent, which is only slightly above
the maximum. With a mixture of 2 per cent of shells with the same
fiber content, the resultant mixture would yield a fiber content of 6.8
per cent, which is within the maximum 7 per cent limit.
1921] TABER: DETERMINATION OF SHELLS IN CACAO PRODUCTS 257
Knapp and McLellan give a range of from 5.3 to 6.8 per cent on a
moisture fat-free basis in the determination of crude fiber on pure cocoa
samples sent to different chocolate laboratories in England. The
writer is unable to account for this wide variation, as in his experience
duplicate determinations agree within one-tenth of 1 per cent, particu-
larly with material within that range of fiber content.
It seems, therefore, that collaborative work might well be done on
this determination during the coming year. The consensus of opinion
seems to be that this is the best single chemical determination even
though it does not show the presence of small amount of shells.
Fortunately, there is another method which can be used in the determi-
nation of the shell content of cacao products. The microscope has
given great promise of usefulness in this field. This method is based
on the presence of various characteristic tissue found in the shell of the
cocoa bean, such as the spongy tissue, stone cells, spiral vessels, muci-
lage cells, etc. Hanausek'! states that the mucilage cells alone are
characteristic. Beythien and Pannwitz? make use of the mucilage cells
as well as the stone cells. They state that if more than 6 mucilage
cells with a magnification of 90 are found when 4 or 5 mg. of fat-free
chocolate are used, the cocoa is adulterated with more than 5 per cent
of shells. The writer’s work would indicate that about 6 mucilage
cells are found in 4 mg. of fat-free chocolate containing only 2 per cent of
shells, and in 5 per cent of shells there would be at least 15 mucilage cells.
Boericke*? makes use of the stone cells as a criterion of shell content,
but does not make a complete count of the number found in any given
quantity of material.
Collin‘ makes use of very fine sieves for separating the insoluble fiber
from the starchy material and, after decolorizing the residue, examines it
for microscopic characteristics, the microscope apparently being used
for qualitative results alone.
Various analysts have used quite different procedures for preparing
the chocolate material for examination, but this subject can not be
discussed in detail. Several analysts in the Bureau of Chemistry have
used the method of counting stone cells in a given quantity of material
for some years past. The procedure is as follows:
Transfer 5-10 grams of the chocolate or cocoa to a centrifugal bottle, and treat
with successive portions of gasoline or ether, centrifugalizing thoroughly each time
until the fat is removed. Then wash the sample with water in the same way to re-
move sugar. After the sugar has been removed, finally wash the sample with alcohol
and ether, dry, and mix thoroughly. Weigh accurately 2 mg. of the sample on a glass
slide, add 1-2 drops of 60% chloral hydrate solution, mix thoroughly by stirring with
the point of a needle, cover with a cover glass and allow to stand until the tissues have
1 Apoth. Zlg., 1915, 30: 590.
2 Z. Nahr. Genussm., 1916, 31: 265.
? Pharm. Zentralhalle, 1916, 57: 283.
‘J. pharm. chim., 1910, 7th ser., 1: 329.
258 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
cleared. In case haste is necessary, the clearing may be obtained by gentle heating.
Examine the entire amount, counting all the stone cell groups, and compare with a
mount, prepared in the same way from a standard sample containing a known per-
centage of cocoa shells.
The accuracy of the method has not been thoroughly tested by
collaborative work. Known samples were sent to a few analysts who
had had experience in the use of the method, but, unfortunately, the
returns have not been sufficient to draw any definite conclusions. It
would seem, however, that with a maximum of 5 per cent of shells on
the fat-free basis, fairly accurate results may be secured. When larger
amounts of shells are present, the error appears greater. This is not
so serious a matter, however, since goods manufactured by reputable
manufacturers and under good factory conditions will contain con-
siderably less than 5 per cent of shells on the fat-free basis. The per-
centages found on the fat-free basis will necessarily be divided by 2 to
estimate them on the original chocolate liquor, which contains approxi-
mately 50 per cent of fat. Thus the error of examination is divided by 2.
The disadvantages of this method are that it is extremely trying and
tedious, requiring considerable experience in the absolute identification
of some of the stone cells on account of the thick tissue often encountered.
The statement of Knapp and McLellan that they found no procedure
which would determine as low a percentage of shell as 5, is quite con-
trary to the experience of the writer and others in the Bureau of Chem-
istry. They tried the microscopic method, but evidently did not suc-
ceed in making it quantitative. The counting of the mucilage cells
is apparently a less accurate gauge of the amount of shell tissue present,
since the number of these cells found for a given amount of material is
considerably less than the number of stone cells. It has the advantage
that these cells are large and comparatively easy to distinguish.
In comparing results by the microscopic method with those obtained
by the crude fiber determination, one sometimes meets conflicting data,
as shown in Table 4.
TABLE 4.
Moisture and fat-free basis.
SHELL MICROSCOPIC
SAMPLE NUMBER | CRUDE FIBER*® , EXAMINATIONT
per cent per cent
1 5.26 2
2 6.95 2
3 7.70 4-5
4 6.23 4
5 6.67 10
6 7.01 3
7 8.13 10-12
8 6.59 12-14
9 6.55 20
*Analyst, M. L. Offutt.
tAnalyst, B. H. Silberberg.
1921| TABER: DETERMINATION OF SHELLS IN CACAO PRODUCTS 259
RECOMMENDATIONS.
It is recommended—
(1) That further study be made of the microscopic method for the
examination of cacao products for shells in order that its limit of accuracy
may be determined by experienced microscopists.
(2) That further study be made of the chemical methods for shells,
particularly crude fiber, with a view to obtaining more data for the
interpretation of results, and for the purpose of correlating chemical
results with microscopical results.
It is the opinion of the writer that the present method of stating the
permissible amounts of ash, fiber, and starch is unscientific and results
in some confusion. It would be simpler and the figures could then be
much more easily applied to all cacao products if these constituents
were stated on the fat and moisture-free basis. To illustrate, paragraph
6 of the standards! reads as follows:
Sweet chocolate, sweet chocolate coatings, contains in the sugar and fat-free residue
no higher percentage of ash, fiber, or starch than is found in the sugar and fat-free
residue of chocolate.
The standards do not state the percentage of ash, fiber, and starch
found in the sugar and fat-free residue of chocolate. Of course such
figures may be obtained by calculating from paragraph 4, which con-
tains the standards for chocolate, chocolate liquor, etc., but in that
case an error is incorporated if it is assumed that the chocolate has 45
per cent of fat, when it contains, as a matter of fact, more than 50 per
cent of fat.
The same error enters again in the standard for cocoa and sweetened
cocoa in which it is necessary to correct for the fat removed. It is
seen, therefore, that the error of a 45 per cent fat basis enters into para-
graphs 4, 6, 8 and 10. It would, therefore, be more exact and more
scientific to express the standards of all kinds of cacao products on a
fat, moisture, and sugar-free basis.
It is, therefore, recommended— -
(3) That a revision of the standards for cacao products along the
lines indicated be recommended to the Committee on Cooperation with
Other Committees on Food Definitions.
1U.S. Dept. Agr., Office of the Secretary, Circ. 136: (1919), 18.
260 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
CACAO PRODUCTS WITH SPECIAL REFERENCE TO
SHELL CONTENT.
By B. H. Sirperserc (Bureau of Chemistry, Washington, D. C.).
For some time the question of the allowable amount of cocoa shell in
cocoa and chocolate products has been discussed in the Bureau of Chem-
istry. Principaily for the purpose of getting some information on this
subject, W. C. Taber and the writer visited a number of factories in
June and July, 1919, and samples were collected for investigation.
It may be advisable first to describe briefly the different stages in
the process of manufacture of these goods in order to show at what
points quantities of shell may enter in excess of that which is easily
preventable in good commercial practice. Thé beans arrive in this
country in large sacks and are stored in warehouses until needed in the
factory. When taken to the factory they first undergo a cleaning pro-
cess to remove dirt and stones and other extraneous matter. They are
then placed in a roaster, which is generally of the revolving type, where
the beans are carefully roasted for about one-half hour. After the
roasting is completed they are drawn out into trays with perforated
bottoms where they are cooled quickly in order to prevent sweating,
and also to expedite the factory work. This cooling is often accom-
plished by suction or cold air blasts.
The size of beans and thickness of the shell are both factors influencing
the percentage by weight of shell to nib found in any given variety of
bean. Fifteen varieties of raw beans commonly used at the present
time, some clayed and some unclayed, were examined in order to
determine their percentage of shell. Of twenty-four samples of unclayed
beans, including fifteen varieties, the highest shell content found was
15.6 per cent, the lowest 7.3 per cent, and the average 12.1 per cent.
Several of those which were highest in shell had an unusual amount of
pulpy matter from the pod dried on them, a few contained a large
amount of shriveled beans of poor quality, and the beans in most of
these samples were somewhat under average size. Four samples of
clayed beans of three different varieties showed a maximum shell con-
tent of 17.3 per cent, a minimum of 13.5 per cent and an average of
15.5 per cent.
After the roasted beans have been cooled they are cracked and fanned
to remove the shell. These operations are both accomplished in one
machine, the cracker consisting of rolls between which the beans are
broken to loosen the shell from the nibs. After this cracking process,
the lighter shell particles are separated from the heavier chocolate nibs
by air blasts which also separate the nibs of different gravity, the lighter
shell particles being removed at one end of the machine together with
1921] SILBERBERG: SHELL CONTENT OF CACAO PRODUCTS 261
the lighter particles of broken nibs. Shell particles, which are unusually
heavy, due to claying or perhaps to attached tissue, will naturally come
through with the nibs. Whole beans which are shriveled or too small
to have been caught between the cracking rolls may come through
with the larger nibs. These are the factors which influence to the
largest extent the shell content in the final product. On account of
the variation in the size of beans and in the weight of the shells in differ-
ent varieties of beans, it is customary to crack and fan each variety
separately in order that the rolls may be set and the blast adjusted
accordingly. The nibs of different varieties are usually blended before
grinding.
The germs of the beans usually come through with the small-sized
nibs and, in most factories, are removed by running the nibs over vibrat-
ing planes which are perforated to allow the small germ to pass through
without any great loss of nibs. The percentage of germ in twenty-eight
samples of fifteen different varieties of beans showed a maximum of
0.9 per cent, a minimum of 0.5 per cent and an average of 0.73 per cent.
The last or lightest portion containing some very small particles of
nibs and a considerable quantity of shell particles carried over by the
blast is usually discarded in the best factories. This final separation,
sometimes called ‘‘fines’”’ or ‘‘dust’’, usually consists of 50 per cent or
more of shell. In some factories efforts are made to clean the fines to
recover some of the nibs. As a rule this has not appeared to be satis-
factory.
In the different separations made by the fanner the percentage of
shell is nearly always much higher in the finest separation, running as
high as 10 per cent and over in some of these last divisions. It should
be emphasized, however, that a rather small proportion by weight of
these last separations is used in the final product.
The nibs after leaving the fanner are blended for the purpose of
obtaining a desirable flavor, the stronger flavored beans being used
with some of milder flavor. It is usual to make a blend of two or three
varieties of beans, although sometimes more are used. The nibs are
placed in a hopper which feeds directly into the mills composed of two
or three sets of revolving stones. The ground nibs come from these
stones in the form of a heavy viscous mass, known to the trade as*‘choco-
late liquor’. This liquor is the material from which all finished goods
are made. In some cases the liquor is run into presses where more
th n half of the cocoa butter is extracted. The residual press cake is
then ground and run through bolting cloth and is the cocoa of com-
merce. There seems to be no uniformity in the size of bolting cloth
used.
The liquor from which fat is not extracted is further refined for coat-
ings, sweet chocolate or milk chocolates. This refining consists in
262 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
further grinding and working in melangeurs, steel rolls, and longitudinals
to make the goods smoother and more palatable. During this process
cocoa butter, sugar, or milk may be added, according to the finished
product desired. After this refining is completed the chocolate is often
allowed to stand in a warm room for some days to “‘season”’ or develop
flavor before it is run into molds.
Samples of nibs were collected from the spouts of the hoppers as
they fed into the grinding mills in order to have cleaned nibs which
represented the liquor used in the final product. In each of these samples,
which in most cases were blends of several varieties of beans, the per-
centage of shell was determined by hand separation with the following
results:
PERCENTAGE OF SHELL IN NIBS FROM HOPPERS.
Eleven factories out of seventeen showed an average of 1.32 per cent,
a maximum of 2.55 per cent, and a minimum of 0.65 per cent of shell.
Fifteen factories, including the eleven just mentioned, showed an average
of 1.72 per cent, a maximum of 3.65 per cent, and a minimum of 0.65
per cent of shell. Seventeen factories, the total number visited, showed
an average of 2.24 per cent of shell.
It may be seen that with the exception of two factories in which the
shell content in the nibs was evidently excessive, the average percentage
of shell in nibs in fifteen factories was below 2 per cent. Although
nibs from six of those factories contained shell in excess of 2 per cent
it is believed that for the most part this was due to the use of fines and
to careless and uncleanly factory practices, and in one case was partly
due to disturbed factory conditions incident to the installation of new
machinery. Another important factor which influenced the percentage
by weight of shell in these nibs was the presence in at least three cases
of clayed beans in the blend. While this makes the shell content, as
determined in this way, appear excessive, the actual amount of shell
tissue, minus the clay, as determined by chemical and microscopical
methods, would be less than indicated by weight. This clay, which
here figures as weight of shell, would appear in the chemical analysis as
acid-insoluble ash and would not figure at all as shell in the microscopical!
examination.
It may also be seen that of these fifteen factories the nibs from five,
or 33 per cent, contained 1 per cent or under of shell, while eight, or 53
per cent, had 1.5 per cent or less of shell.
From these results it seems reasonable to conclude that a fair limit
of tolerance for shell in cocoa or chocolate products would be 2 per cent
on the basis of the original nibs or liquor, or 4 per cent on a fat and
sugar-free basis.
1921] BAUGHMAN: REPORT ON CACAO BUTTER 263
REPORT ON METHODS FOR THE EXAMINATION
OF CACAO BUTTER.
By W. F. Baucuman (Bureau of Chemistry, Washington, D. C.), Referee.
The last report of a referee on cacao butter was made by Eugene
Bloomberg at the 1916 meeting of the association’. His report was
concerned with the critical temperature of dissolution determination
and a test for tallow and hydrogenated oil which he had originated.
The committee on recommendations of referees recommended that these
two methods be further studied. Your referee thought it advisable,
therefore, to make a critical examination of these two methods before
again submitting them to collaborators. After the conclusion of this
examination, there was not sufficient time to send out samples to col-
laborators. So the present report contains no results of collaborative
work, but it is hoped that the investigation conducted by the referee
has cleared up some obscure points and made the methods more reliable
and workable.
The critical temperature of dissolution determination is practically
the Valenta test?. Cacao butter and other fats dissolve in acetic acid
on heating. The critical temperature of dissolution is the temperature
at which a solution of 5 cc. of melted fat in 5 cc. of glacial acetic acid
becomes turbid on cooling. Practically all potential substitutes for
cacao butter with the notable exceptions of hydrogenated oils, oleo-
stearine and tallow, have a considerably lower temperature of dis-
solution than cacao butter, and when mixed with pure cacao butter
they lower the critical temperature hy an amount approximately pro-
portional to the amount substituted. The critical temperature of
dissolution of any fat varies with the strength of the acetic acid, and
Bloomberg therefore recommends that the acetic acid be standardized
against an authentic sample of cacao butter. The purity or sophis-
tication of the sample under examination is indicated by comparing its
critical temperature with that of the authentic cacao butter.
Bloomberg sent six samples of adulterated cacaa butter to five col-
laborators. They made a critical temperature of dissolution determina-
tion on each sample. Four reported adulteration of each sample. The
fifth drew no conclusions from his examinations, but his results plainly
indicated adulteration.
It is obvious that the reliability of this method depends on the con-
stancy of the critical temperature of dissolution of cacao butter pro-
duced under different conditions of manufacture, or from beans grown
in different localities. The results in Bloomberg’s report do not shed
1 J. Assoc. Official Agr. Chemists, 1920, 3: 486.
2J. Soc. Chem. Ind., 1884, 3: 643.
264 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TaBLe 1.
Cruical temperature of dissoiution of cacao builer and substilules. :
TEMPERATURE OF DISSO-
SAMPLE DESCRIPTION OF SAMPLE ACID VALUE LUTION
NUMBER ——
Observed Corrected
eG: oC
1 Cacao butter, Standard 1.07 90. 91.3 |
9 | Cacao butter, Trinidad 1.22 89.5 91.5
3 Cacao butter, Sanchez 1.08 90.5 91.8
4 Cacao butter, Caracas 1.12 90.5 91.8 {
5 | Cacac butter, Bahai 1.12 89.5 90.8 i
6 | Gacao butter, Accra 1.55 90. 91.8 |
7 | Cacao butter, commercial sample 3.51 86. 90.2
g | Cacao butter, commercial sample 2.86 86. 89.2 }
9 | Cacao butter, commercial sample 2.55 86.5 89.6 |
10 | Gacao butter, commercial sample 2.97 87. 90.6
11 | Coconut oil stearine . Soluble at room oe }
temperature
12 | Palm kernel oil stearine Solubleay room
temperature
13 | Cottonseed oil eer 52.5
14 | Cottonseed oil (wintered) 0.30 43. ipheas
15 Cottonseed oil stearine foray 60.5 she }
16 Sesame oil ee 52. eed
17 Peanut oil 1.00 65.
18 | Hydrogenated cottonseed oil Cerre 98.5
19 | Tallow eerae 85.
20 | Oleo stearine aha 91.
21 Cacao butter containing 5% coconut oil
stearine eros 85. Aon }
92 | Cacao butter containing 10% coconut oil
stearine ee os 82.5 nes
23 | Cacao butter containing 20% coconut oil |
stearine aokis ie. Aah |
24 | Cacao butter containing 5% palm kernel
oil stearine Berets 87.
25 | Cacao butter containing 10% palm kernel
oil stearine hate 82.5
26 | Cacao butter containing 20% palm kernel
oil stearine stays 74.
pe Cacao butter containing 5% cottonseed oil Soaks 87.5
98 | Gacaobutter containing 10% cottonseed oil se bt 86.
29 Cacao butter containing 20% cottonseed oil ADC 83.
30 | Cacao butter containing 10% cottonseed
oil stearine arene 87.
31 Cacao butter containing 20% cottonseed
oil stearine Ae 83.
32 Cacao butter containing 30% cottonseed
oil stearine Pat 80.
33 Cacao butter containing 10% peanut oil Pa 86.5
34 Cacao butter containing 20% peanut oil Mee 84.
35 Cacao butter containing 30% peanut oil eratets 82.
much light on this point. Accordingly, the critical temperature of
dissolution has been determined on six samples known to be pure and
four commercial samples supposed to be pure. The results are given
in Table 1. Samples 2 to 6, inclusive, were pressed in a commercial
ee
1921] BAUGHMAN: REPORT ON CACAO BUTTER 265
TABLE 2.
Influence of acidity of cacao butter on the critical temperature of dissolution in glacial
acelic acid.
SESOLUAION FALLIN DISSOLU-
Sample SeORIBON Oeck ACID » ales ON | TION TEMPERA-
Number Y Reka! aaa se VALUE TEMPERS | TURE PER UNIT
ATURE OF ACID VALUE
°G. °G:
i Cacao butter (standard) 1.07 89.
2 | Cacao butter to which has been added
cacao butter fatty acids 3.22 86. 1.39
3 | Cacao butter to which has been added s
cacao butter fatty acids 5.92 83. 1.29
4 | Cacao butter tc which has been added
cacao butter fatty acids 11.12 78. 1.09
5 | Cacao butter to which has been added
cacao butter fatty acids 19.68 67. 1.18
plant in the presence of H. S. Bailey, formerly of the Bureau of Chem-
istry, from beans grown in various localities. They represent, there-
fore, butters of commercial grade. Samples 7 to 10, inclusive, were
collected in the open market by W. C. Taber. The observed critical
temperatures of the first six samples are practically constant, but the
results obtained on the other four samples are lower and the variations
are wide enough to cause one to be suspicious of their purity. How-
ever, the acid values of the four commercial samples are greater than
the acid values of the six authentic samples.
It is well known that the acidity of a fat influences the results of the
Valenta test. Free acids in cacao butter have a similar influence on
the critical temperature of dissolution. The influence is illustrated by
the results given in Table 2. j
Samples 2 to 5, Table 2, were prepared by adding portions of free
fatty acids obtained from pure cacao butter to the butter represented
by Sample 1. The third column in that table gives the acid values
(mg. of potassium hydroxide required to neutralize the free fatty acids
in 1 gram of the sample). In the fourth column are tabulated the ob-
served critical temperatures, and in the fifth column is given the
lowering of critical temperature per unit of acid value. The lowering
is proportional to the acid value. One unit of acid value causes an
average reduction of 1.2° C. If this factor is used to correct the results
obtained on the commercial butters (Samples 7 to 10, Table 1) it is
found that the corrected results are in line with those for the authentic
samples. It is, therefore, important to determine the acidity and to
make the proper correction if necessary.
The critical temperatures of dissolution of some of the possible adult-
erants of cacao butter have been determined (Samples 11 to 20). With
266 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
the exception of hydrogenated cottonseed oil, tallow and oleo stearine,
they are all considerably lower than cacao butter.
The results obtained on Samples 21 to 35 show to what extent adulter-
ation with these various products lowers the critical temperature of
dissolution. The results indicate that one should, by the use of this
method, be able to detect 5 per cent or more of coconut or palm kernel
oil stearine. Peanut oil, cottonseed oil and cottonseed oil stearine
have higher critical temperatures than coconut or palm kernel oil stear-
ine, and when mixed with cacao butter, the critical temperature of the
latter is reduced to a less extent. Perhaps one can not detect with
certainty adulteration with less than 10 per cent of these products.
The apparatus and details of the method used by the author in making
the determination may be of interest. A thermometer is inserted
tightly into a cork fitting a 6X? inch test tube, a small groove being cut
in the side of the cork for the escape of hot air. The thermometer
extends down far enough to be covered completely by 10 cc. of liquid.
Graduation marks are scratched on the test tube at 5 cc. and 10 ce.
from the bottom. The melted fat is poured into the tube up to the
5 cc. mark and then acetic acid up to the 10 cc. mark. The cork holding
the thermometer is inserted and the test tube is placed in a larger one
(44 X13 inches) containing glycerol, and held firmly in place with a cork.
Heat is applied and the apparatus frequently shaken until a clear solu-
tion of fat in acetic acid is obtained. The solution is then allowed to
cool with constant shaking, without removing it from the glycerol
bath, and the temperature noted at which it becomes turbid. By not
removing the solution from the glycerol bath, it cools more slowly,
and permits the dissolution temperature to be read more sharply and
accurately. The fat and acid should be measured very carefully as
small variations in the proportions of fat and acid affect the results.
The fat should be filtered through filter paper in a hot air oven (100°C.)
in order to remove traces of moisture. It is then well to allow it to
cool somewhat before measuring the 5 cc. sample and to measure the
sample and standard butter at the same temperature. The acetic acid
used was labeled ‘‘Acid Acetic, Glacial, contains 99.5% of absolute
acetic acid.’’
TEST FOR HYDROGENATED OIL, TALLOW, OLEOSTEARINE,
LARD AND PARAFFIN.
Bloomberg’s directions for making the acetone test for hydrogenated
oils and tallow are to dissolve 5 cc. of melted fat in 5 cc. of acetone,
heating if necessary, and to allow the mixture to stand overnight in
cold water.* If tallow or hydrogenated oil is present, a flocculent
precipitate is obtained. It is the opinion of the referee that these
directions are too indefinite. If the water is very cold, cacao butter
1921] LEPPER: REPORT ON COFFEE 267
will solidify and the analyst might confuse this with the precipitate
caused by tallow or hydrogenated oil. Indeed, one of Bloomberg’s
collaborators had this experience and reported the presence of an
adulterant in a sample of pure cacao butter. If the room is not too
warm (say at 20° to 22°C.) the solution of fat in acetone may be allowed
to stand overnight at room temperature. If hydrogenated oil, tallow,
oleostearine, lard, or paraflin is present, a precipitate is formed, while
pure cacao butter will not solidify or precipitate.
In order to shorten the time required for the test, Bloomberg suggests
using a mixture of equal parts of acetone and carbon tetrachloride
instead of acetone. Since fats are more soluble in this mixture, it is
necessary to cool the solution in ice water for 5 to 30 minutes. A floccu-
lent precipitate is obtained if hydrogenated oil, tallow, oleostearine,
lard or paraffin is present. A blank should be run using pure cacao
butter. Sometimes a precipitate is obtained in a sample of pure butter,
so if the sample being tested gives a precipitate, it should be removed
from the ice water and allowed to remain at room temperature for a
time. If the precipitate is only solidified cacao butter, it will soon
melt and go into solution; if the precipitate is due to any of the above-
mentioned fats, a much longer time will be required for it to go into
solution. Less than 5 per cent of these substitutes can be detected
by this method. The referee regards the acetone-carbon tetrachloride
mixture as preferable.
RECOMMENDATIONS.
It is reeommended—
(1) That further collaborative work be done on the critical tempera-
ture of dissolution determination, especially to test the accuracy of the
correction factor for acidity.
(2) That the test for tallow, hydrogenated oils, lard, paraffin, etc.,
be further studied, since the acetone-carbon tetrachloride test has
never been tested by collaborators.
REPORT ON COFFEE.
By H. A. Lepper (Bureau of Chemistry, Washington, D. C.), Referee.
The determination of caffeine in coffee has held the attention of the
association continuously since 1908 with the exception of 1912, when
no report was made on coffee, and 1916, when experimental work on
the moisture content and the chemical composition of raw and roasted
coffees was reported and no collaborative work was undertaken.
When the present referee was appointed in 1917, the Stahlschmidt
method for caffeine in coffee had been provisionally adopted two years
268 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
previously! and its further study with a view to official adoption in
1917 was recommended. In the study of the Stahlschmidt method in
1917, comparison was made with the Fendler-Stiiber method®. The
advantages of the latter were such that it was adopted as a tentative
method and no further action was taken on the Stahlschmidt method.
In 19193, no meeting being held in 1918, the Fendler-Stiiber method
was critically studied and a slight error was found, because of the action
of the potassium permanganate on the caffeine during the process of
purification when carried out at room temperature. Collaborative work
was undertaken on a modification, providing for purification at the
temperature of ice, the object of which was to eliminate this error.
The results did not warrant the adoption of the modification as the
caffeine obtained was inferior in purity to that obtained by the original
treatment. The original method was retained as a tentative method
with such other minor modifications as tended toward easier and more
accurate manipulations. The maximum error found when the purifica-
tion was conducted at room temperature was 1 per cent which, on a
coffee containing 1.50 per cent of caffeine, (a maximum content in the
experience of the referee) would mean an error of 0.015 per cent on the
determination. This percentage of error is well within the limits of
error of the method itself, as well as within the error of the personal
equation, as shown by the various collaborative duplicate results re-
ported in 1917 and 1919.
The advantages of the Fendler-Stiiber method are: Rapidity, it being
possible to make a determination in about 3 hours; ease of manipulation,
no extensive apparatus being necessary; and the production of an
exceptionally pure caffeine residue. Collaborative investigation has
established its accuracy and general usefulness on green, roasted, and
on the so-called ‘“‘decaffeinated” coffees. In view of the marked ad-
vantages of the method and its accuracy, the slight error previously
discussed not being considered of sufficient magnitude to condemn the
method, it is believed that it should be retained, in the form adopted
in 19194, as a tentative method.
At the last meeting of the association, the Power-Chesnut method®
for caffeine was recommended to the referees on coffee and tea for study.
These authors devised a practically new method although they termed
it “An Improved Method for the Quantitative Determination of Caffeine
in Vegetable Material”. Each step of the method was studied by them
and judged to be accurate. A series of control experiments, to ascertain
whether caffeine was lost in any of the manipulations of the method,
1J. Assoc. Official Agr. Chemists, 1917, 3: 21.
2Z. Nahr. Genussm., 1914, 28: 9.
3 J. Assoc. Official Agr. Chemists, 1921, 4: 526.
4 Tbid., 533.
5 J. Am. Chem. Soc., 1919, 41: 1298.
1921] LEPPER: REPORT ON COFFEE 269
was carried out by the referee before collaborative samples were sent
out.
The first step to receive attention was the alcoholic extraction of the
sample. In order to determine whether the extraction had been com-
plete, a delicate test for caffeine was desirable. Gomberg! found that
Wagoner’s reagent used in the presence of hydrochloric acid would detect
caffeine by precipitation of caffeine periodide in a dilution of 1 to 10,000.
He also found that the reagent would not precipitate caffeine in the
presence of fairly strong acetic acid. These findings were verified by
the referee, using Wagner’s reagent?. The delicacy 1 to 10,000 would
allow the detection of 0.1 mg. in 1 cc. of solution. Two roasted and
two unroasted coffees were extracted for 8 hours with alcohol as directed
in the Power-Chesnut method. The residual coffees were then mois-
tened with 10 per cent ammonium hydroxide and re-extracted with
chloroform. After evaporation, the chloroform residues were dissolved
in 1 cc. of water. To each solution Wagter’s reagent and a few drops
of dilute acetic acid were added. The slight precipitates formed were
filtered off and the addition of 4 drops of hydrochloric acid failed to
produce even a turbidity in any of the four filtrates. This indicates
that the alcoholic extraction removed all the caffeine from the coffees as
the test applied showed that chloroform failed to further extract caffeine
or, at least, that the quantity so extracted was less than 0.1 mg.
The use of heavy magnesium oxide was shown by Power and Chesnut
not to be detrimental to the complete recovery of caffeine and a reference’
is cited by them wherein it is reported that magnesia has no action on
caffeine at 100°C. Markownikoff! and Mulder’ devised methods for
the determination of caffeine wherein magnesia is employed. As none
of these authors used the procedure of evaporation of an alcoholic
extract in the presence of magnesia with subsequent solution of the
caffeine in hot water, as provided in the method under consideration.
this step was studied. Two samples of caffeine of 0.2000 gram each
were dissolved in 50 cc. of alcohol and 50 cc. of water and 10 grams of
heavy magnesium oxide were added. The resulting mixtures were
evaporated to dryness on the steam bath, extracted with hot water,
filtered, and washed with hot water until the filtrate measured 250 cc.
On extraction of the filtrate with six successive 25 cc. portions of chloro-
form, evaporation of the chloroform, and drying, residues weighing
0.1998 and 0.1980 gram were obtained. This caffeine had an uncorrected
melting point of 230°C. These recoveries indicate that the magnesia,
as used in the method, is without action on the caffeine. The heavy
1 J. Am. Chem. Soc., 1896, 18: 331.
? Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 292.
3 Bull. soc. chim., 1897, 3rd ser., 17: 597.
‘J. Russ. Phys.-Chem. Soc. (Phys. Pt.), 1876, 5th ser., 8: 226.
* Z.anal. Chem., 1873, 12: 107.
270 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
magnesium oxide used in these tests met the U.S. P. requirements with
respect to soluble salts and carbonates.
The next step to be considered was the boiling of the filtrate from
the magnesia treatment with 10 cc. of 10 per cent sulfuric acid for 30
minutes. The authors of the method found no action of sulfuric acid
on caffeine. Zoller! and Costes? both propose methods for the determi-
nation of caffeine, using sulfuric acid in the process. Neither of them
however, determined whether this acid is without action on the base.
Therefore, the referee boiled 3 portions of caffeine of 0.2000 gram each
in 200 cc. of water, increasing the quantity of acid in one case and
lengthening the period of time in another case over that proposed in
the method. The caffeine after treatment was extracted with six
successive 25 cc. portions of chloroform, the chloroform evaporated and
the residues weighed. The conditions of treatment and recoveries are
given in the following table:
TABLE 1.
Treatment of caffeine solution with sulfuric acid.
10% SULFURIC TIME OF WEIGHT OF CAFFEINE UNCORRECTED
ACID TREATMENT RESIDUE MELTING POINT
cc. minules gram °C.
10 30 0.1999 230
10 120 0.1998 230
40 30 0.1994 230
These results indicate that the treatment with sulfuric acid of the
concentration and for the time specified in the method has no effect on
the caffeine.
The final procedure specified in the method for purifying the caffeine
is a treatment of the chloroform extract with dilute potassium hydroxide
to remove coloring substances. Paul and Cownley* used dilute sodium
hydroxide for the same purpose in a manner similar to that directed
in the method under consideration. Dyorkowitscht employed barium
hydroxide in a method for the determination of caffeine but not in a
similar manner. Neither of these authors did any work to determine
whether treatment with alkali solution affected the caffeine. However,
Power and Chesnut found no effect by the alkali when used as pre-
scribed in this method. This finding was verified by the referee. Two
samples of 0.2000 gram of caffeine were dissolved in 150 cc. of chloro-
form and the two solutions washed with 5 cc. of 10 per cent potassium
' Neues Reperlorium Pharm., 1871, 20: 457; Ann. 1871, 158: 180.
2 Ann. chim. anal., 1912, 17: 246.
t Pharm. J., 1887, 3rd ser., 18: 417
4 Ber., 1891, 24: 1945.
1921] LEPPER: REPORT ON COFFEE 271
hydroxide solution. The hydroxide was washed several times with
small portions of chloroform which were added to the original chloro-
form solution. On evaporation and drying, residues of caffeine weigh-
ing 0.1990 and 0.1995 gram were obtained, having an uncorrected
melting point of 230°C. It is evident that the alkaline washing is
without effect on the caffeine.
The caffeine used in the preceding tests was Merck’s U. S. P. which
was recrystallized from water and dried at 100°C. Determination of
nitrogen showed the caffeine to be 99.5 per cent pure. It had an un-
corrected melting point of 230°C. Comparison of the melting points
found on the caffeine residues obtained in the tests indicated that the
caffeine was unaltered in the various procedures to which it was sub-
jected.
Two samples of coffee, (A) a roasted Santos and (B) a coffee from
which it was claimed that 95 per cent of the caffeine had been removed,
were finely ground and sent out for collaborative tests. The following
directions, which have been slightly changed, were sent to each col-
laborator. The changes are of a minor nature and in no way affect
the important steps of the method.
POWER-CHESNUT METHOD FOR THE DETERMINATION OF
CAFFEINE IN COFFEE.
DETERMINATION.
Moisten 10 grams of the finely powdered sample with alcohol, transfer to a Soxhlet,
or similar extraction apparatus, and extract with alcohol for 8 hours. (Care should
be exercised to assure complete extraction.) Transfer the extract with the aid of hot
water to a porcelain dish containing 10 grams of heavy magnesium oxide in suspension
in 100 cc. of water. (This reagent should meet the U. S. P. requirements.) Evap-
orate slowly on the steam bath with frequent stirring to a dry, powdery mass. Rub
the residue with a pestle into a paste with boiling water. Transfer with hot water
to a smooth filter, cleaning the dish with a rubber-tipped glass rod. Collect the filtrate
in a liter flask marked at 250 cc. and wash with boiling water until the filtrate reaches
the mark. Add 10 cc. of 10% sulfuric acid and boil gently for 30 minutes with a fun-
nel in the neck of the flask. Cool and filter through a moistened double paper into
a separatory funnel and wash with small portions of 0.5% sulfuric acid. Extract
with six successive 25 cc. portions of chloroform. Wash the combined chloroform
extracts in a separatory funnel with 5 cc. of 1% potassium hydroxide solution. Filter
the chloroform into an Erlenmeyer flask. Wash the potassium hydroxide with 2
portions of chloroform of 10 cc. each, adding them to the flask together with the chloro-
form washings of the filter paper. Evaporate or distil on the steam bath to a small
volume (10-15 cc.), transfer with chloroform to a tared beaker, evaporate carefully,
dry for 30 minutes in a water oven, and weigh. The purity of the residue can be tested
by determining nitrogen and multiplying by the factor 3.464.
The results of the collaborators, appearing in Table 2, show that the
method is well adapted for general analytical procedure, that good
duplicates can be obtained and that the results of independent analysts
agree as closely as could be expected.
272 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TABLE 2.
Determination of caffeine by the Power-Chesnut method.
CAFFEINE BY WEIGHT
Sample A Sample B
COLLABORATOR
Gravi- N X Gravi- N X
metric 3.464 metric 3.464
per cent per cent per cent per cent
M. L. Offutt, Bureau of Chemistry, 1.69 1.38 0.28 0.13
Washington, D. C. Se here 0.32 0.15
D. B. Scott, Bureau of Chemistry, 1.55 1.48 0.24 0.17
Washington, D. C. 1.55 1.44 0.20 0.14
J. I. Palmore, Bureau of Chemistry, 1.50 1.40 0.22 0.15
Washington, D. C. 1:52 1.44 0.21 0.14
R. E. Andrew, Agricultural Experiment Station,
New Haven, Conn. 1.51 1.47 0.21 0.17
C. E. Shepard, Agricultural Experiment Station,
New Haven, Conn. 1.49 1.45 0.21 0.18
Louis Pine, U. 8. Food and Drug Inspection 1.49 1.41 0.20 0.18
Station, New York, N. Y. 1.50 1.43 0.21 0.19
GC. W. Harrison, U.S. Food and Drug Inspection
Station, Baltimore, Md. le aV/ 0.22
H. J. Wichmann, U.S. Food and Drug Inspec-
tion Station, Denver, Colo. 1.53 opps 0.21 sented
J. H. Bornmann, U.S. Food and Drug Inspection} 1.39 1.32 0.21 0.17
Station, Chicago, III. 1.44 1.34 0.20 0.16
H. A. Lepper. 1.53 1.47* 0.26 0.17*
1.50 1.42* 0.25 0.17*
*Determination made in the Nitrogen Laboratory of the Bureau of Chemistry, Washington, D. C.
In Table 3, the results of the analysis of one sample of unroasted
and one sample of roasted coffees used as collaborative samples in 1919,
are given and comparison is made with the results obtained by the
author by the Fendler-Stiiber method.
TABLE 3.
Determination of caffeine by the Power-Chesnul and Fendler-Stiiber methods.
POWER-CHESNUT METHOD FENDLER-STUBER METHOD
SAMPLE Caffeine Caffeine
Gravimetric N X 3.464 Gravimetric N X 3.464
per cent per cent per cent per cenl
Coffee, roasted 1.21 1.10 1.19 1.16
Coffee, unroasted 1.28 1.20 1.34 1.26
The Power-Chesnut method is shown to be founded on accurate
principles, to give results agreeing with those obtained by the tentative
Fendler-Stiiber method, to give good results by analysts, in general,
and to work equally well on roasted, unroasted and on so-called “‘de-
caffeinated” coffees. It has the advantage of being a flexible method
in that the amount of sample can be varied and it is adaptable to various
1921] LEPPER: REPORT ON COFFEE 273
forms of vegetable material. This is the first year that the Power-
Chesnut method has been studied by the association but it is felt that
the results and conditions justify its adoption as an official method.
The authors were members of this association when the method was
devised after thorough investigation in the Phytochemical Laboratory
of the Bureau of Chemistry. It has also been critically studied by the
referee and collaborative results warrant its adoption. The method
contains no radical departure from recognized principles and all the
reagents employed have been used or suggested by two or more authors
in connection with the determination of caffeine. This action is especially
desirable as the determination of caffeine has received attention by the
association for the past twelve years. The history of the determination
of caffeine, both in and out of the association, shows that the large
number of methods suggested are due in part to adoptions, revisions
and modifications until nothing seems to remain to be done except
revise and modify and it does not appear that further progress or ad-
vantage could be gained by continuing the study of the method. The
action suggested in this report, if adopted, will provide the association
with an official method of scientific accuracy and wide adaptability
and with an accurate tentative method to be used when results are
desired quickly, to be confirmed, if necessary, by the official method.
If the association believes that the conditions do not warrant the adop-
tion of the Power-Chesnut method as official, it is recommended that it
be adopted as a tentative method and that further work on caffeine
in coffee be discontinued until the methods for other constituents are
improved.
RECOMMENDATIONS.
It is recommended—
(1) That the Fendler-Stiiber method for the determination of caffeine
in coffee be retained as a tentative method and be designated as a
method to be used when quick results are desired.
(2) That the Power-Chesnut method, page 271, be adopted as an
official method.
(3) That the Stahlschmidt method for the determination of caffeine
in coffee be dropped.
(4) That the referee on coffee next year study the methods for the
determination of other constitutents.
274 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
ROBUSTA COFFEE.
By Arno VIEHOEVER and H. A. Lepper (Bureau of Chemistry,
Washington, D. C.).
INTRODUCTION.
The designation “‘Robusta Coffee” is given to a product now grown
in Java on a very large scale. It is, however, not identical with the
coffee generally known as Java coffee, representing Coffea arabica L., and
being the product, which, forty or more years ago, was the only coffee
grown in Java. Since the eighties (1878) of the last century. differ-
ent diseases, among them especially coffee blight, have more and more
extinguished the plantations of Coffea arabica, and even those still
existing in the mountainous districts diminish rapidly. Neither is
Robusta coffee identical with Liberica coffee, which, although of some-
what inferior quality, proved more disease-resistant than Coffea arabica
and was grown instead of the latter in considerable amounts until
within recent years it was replaced by the new variety, Coffea robusta.
This, as we shall see, is now grown in Java in larger amounts than both
Coffea arabica and Coffea liberica Hier. together, due to its many good
qualities—disease-resistancy, rapid growth, early and prolific yield, and
its usefulness as a catch-crop in rubber, cocoanut and other plantations.
ORIGIN, CLASSIFICATION, TERMINOLOGY.
Robusta coffee is of African origin and was found in the Eala dis-
trict of the Belgian Congo by Ed. Luija, one of the travelers for L.
Linden, Belgian horticulturist. Linden sold the plantlets grown from
the seed in the years 1901 and 1902 to planters and the government in
Java under the now well-established name Coffea robusta Linden.
The botanical classification is not fully settled. It is a disputed
question whether Coffea robusta Linden, found native also in the Frenen
Congo by M. Chevalier and sometimes referred to as Coffea robusta
Chevalier, is a species different from Coffea canephora, as believed by
Cramer’, or a variety or form of Coffea canephora Pierre, indigenous to
Central and West Africa, as pointed out by De Wildeman?. Coffea
laurentii, found wild in the Congo region by Emil Laurent in 1918
according to De Wildeman, is nothing but a form of Coffea canephora,
and thus closely related to Coffea robusta. Van Hall® states: ‘Perhaps
two newly imported varieties named Coffea laurentii and Coffea cane-
phora var. sankuruensis must be regarded as belonging to the robusta.”
According to Cramer! Coffea laurentii, Coffea canephora var. sankuruensis
Tea and Coffee Trade Journal, 1918, 35: 418
* Bull. assoc. planteurs Caoutchoue, 1912, 4: 55
4 Agri. Bull, Federated Malay Slales, 1913, 1: 253.
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 275
and Coffea canephora var. kwiluensis or kouilouensis, probably belong to
Coffea robusta. Wurth (See De Wildemann, 1912) considers that the
group or type robusta represents the canephora, quillou, and ugandae
varieties. Wester! similarly speaks of a Coffea robusta type or group,
including the varieties robusta, canephora, quillou and ugandae. Cramer?,
while conceding that Coffea robusta is a mixture of different varieties,
considers Coffea canephora, Coffea ugandae, and Coffea quillou as allied
species rather than as varieties of Coffea robusta.
PART I. BOTANICAL CHARACTERISTICS.
The Robusta group has not yet been subjected to a thorough study.
Plants.—The plants representing the Coffea robusta group are not of
one uniform type, differing in size and shape of the leaves, fruits, etc.
The following may be considered as general characteristics of the Ro-
busta group according to Van Hall’, Gallagher*, and Cramer?:
The habit of the trees is much alike. They are early and strong
bearers, the fruits are small and arranged in dense clusters, bearing
often over sixty fruits. The leaves show rather more variety, but they
are always larger than those of Coffea arabica, and more or less of the
size of the liberica leaf, sometimes smaller, sometimes larger, but never
of leathery appearance, and softer and weaker. The young leaves are
green, not brownish, the basal part of the leafblade is emarginated
toward the stalk. The flowers appear in thick clusters, and are large
and broader petaled than those of Coffea arabica. The fruits, when unripe,
are green and never orange. colored; when almost ripe, vermillion-red;
and when completely ripe, very dark red, with a bluish tinge. The
berries are smaller and especially shorter than in true Java coffee. The
pulpy substance of the berry shows very little development and, conse-
quently, is difficult to remove, necessitating a longer fermentation than
is needed with arabica.
The decided superiority of the Coffea robusta as a cropper over Coffea
arabica is evident from the fact that in Java, under identical conditions,
53 to 97 grams of coffee beans per plant were obtained from arabica
coffee, and 992 grams of robusta. A hybrid, maragogipe, obtained by
grafting Coffea arabica on Coffea robusta, yielded 156 grams, thus demon-
strating Coffea robusta to be a promising stock. According to Wester’,
Cramer found also that only 4 to 5 kilograms of fresh Robusta, but 5
to 6 kilograms of fresh Arabica fruits are required to make 1 kilogram
of coffee.
1 Philippine Agri. Rev. 1916, 9: 121.
2 Tea and Coffce Trade Journal, 1918, 35: 417.
3 Agri. Bull. Federated Malay States, 1913, 1: 253.
4 Agri. Fedcrated Malay States, Bull. 7: (1910), 1.
4 Philippine Agri. Rev., 1915, 8: 45.
276 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Seeds.—The Robusta beans require quick drying in order to loosen
the silver skin. The fact that the silver skin is apparently difficult to
remove is suggested from the appearance of commercial samples which
contain a considerable number of beans showing remains of silver skin
and resulting in a less uniform product. The sample of Coffea robusta
obtained from the Netherlands East Indian Exhibit, San Francisco
Exposition 1915, was practically free from silver skin.
The color, according to Hartwich and other writers, agrees in general
with No. 297, the color tables of Klincksieck and Valette!. It is the
characteristic coffee color, light to olive buff, with faint grayish, greenish
or bluish tint.
The shape is that of the normal coffee bean, not many peaberries
having been observed. The beans are said to be more convex on the
curved side than those of Coffea arabica®. The writers have observed
rather the reverse to be the case. The form, according to Cramer’, is
less oblong than in Java coffee; the circumference on the flat side of the
bean is oval, not edged by straight lines. The average size of com-
mercial samples examined is rather small, though varying considerably.
Hartwich‘, states that he found a sample showing a length of 0.75 to
1.05 cm., a width of 0.6 to 0.7 cm., and a thickness of 0.35 to 0.5 cm.
The measurements made in the Pharmacognosy Laboratory of the
Bureau of Chemistry by J. F. Clevenger and Ruth G. Capen are tabu-
lated below. Ten seeds of each sample were examined.
TABLE 1.
Latitude in size of Robusta coffee beans.
LENGTH WIDTH THICKNESS
Minimum | Average | Maximum| Minimum | Average | Maximum} Minimum | Average | Maximum
cm. cm. cm. cm. cm. cm. cm, cm. cm.
0.75 1.00 1.16 0.55 0.69 0.79 0.37 0.45 0.54
0.61 0.97 1.15 0.56 0.79 0.92 0.35 0.39 0.55
0.73 0.92 1.16 0.48 0.69 0.79 0.37 0.45 0.50
0.62 0.87 1.15 0.52 0.67 0.79 0.54 0.45 0.63
0.65 0.84 1.02 0.55 0.69 0.79 0.33 0.42 0.55
0.69 0.86 0.98 0.50 0.68 0.83 0.33 0.44 0.53
0.71 0.87 1.05 0.58 0.70 0.79 0.35 0.42 0.49
0.70 0.84 1.03 0.55 0.68 0.82 0.34 0.46 0.64
0.90 0.70 0.43
The latitude in sizes thus determined was a length of 0.61 to 1.16 cm.,
a width of 0.48 to 0.82 em. and a thickness of 0.33 to 0.64 cm. These
1 Paul Klincksieck and Th. Valette. Code des Couleurs. 1908, 56.
2 Tea and Coffee Trade Journal, 1915, 29: 223.
* Ibid., 1918, 35: 417.
A. Beythien, C. Hartwich, and M. Klimmer. Handbuch der Nahrungsmittel-Untersuchung, 1913-
1915, 2: 309.
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 277
sizes fall within the sizes observed in varieties belonging to Coffea arabica
and liberica.
Endosperm.—The manner of folding of the endosperm observed upon
a cross section of the bean is considered of value in the identification
and differentiation of coffee. Hartwich points out that the endosperm
of Robusta coffee shows a characteristic recurving, with hook, which
occurs in most of the beans of Robusta. The writers have observed
this recurving and can thus confirm Hartwich’s statement. Inasmuch
-as the curving of the folded edge of the endosperm changes naturally
with the place where the section is made, the authors advise making
the section through the middle of the bean. Pending further investiga-
tion of other varieties of the group Robusta, it is believed that this
characteristic can be used with advantage.
In contrast to the bean of Coffea robusta those of Coffea arabica show a
double or a recurved edge of the endosperm but usually without the
hook. Coffea liberica shows a simple curve, also without a hook. (See
Illustration I, A R L.)
Embryo.—The size of the embryo, and the relative size of the cotyledon
to hypocotyl] is also considered of diagnostical value. Hartwich reports
the size of the embryo of the Robusta coffee to be 0.6 cm. and the relation
in size of cotyledon to hypocotyl 1 to 1.76. Three samples of Robusta
coffee were examined in the Pharmacognosy Laboratory. For purposes
of comparison three samples of Coffea arabica (Mocha Arabica) and two
of liberica were also examined. The results are given in Table 2.
TABLE 2.
Comparative sizes of hypocotyl and cotyledon*.
HYPOCOTYL COTYLEDON
NAME OF SAMPLE Hen
Minimum | Average |Maximum | Minimum | Average | Maximum
cm. cm. cm. cm. cm. cm cm.
Mocha Arabica 0.17 0.27 0.31 0.11 0.17 0.21 1-516
Bourbon Santos 0.25 0.27 0.31 0.14 0.16 0.20 Sa lee/
Bourbon Santos 0.20 0.23 0.28 0.13 0.14 0.19 1: 1.67
Sumatra Robusta 0.29 0.34 0.37 0.14 0.16 0.19 1: 2.08
Java Robusta 0.31 0.34 0.37 0.18 0.18 0.19 8
Sumatra Robusta 0.27 0.32 0.37 0.15 0.17 0.22 1: 1.9
Native Liberica 0.39 0.45 0.57 0.14 0.16 0.21 ROS
Liberica, Venezuela) 0.49 0.51 0.55 0.17 0.19 0.22 S520
*Ten beans of each sample were used.
The results show that the embryos of Coffea robusta are distinctly
smaller than those of Coffea liberica, and also, in average, a little larger
278 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Differentiating characteristics of the coffee beans.
I. Cross section of bean. Approximately X3.
Il. Embryo. Approximately X7.
A. Coffea arabica.
R. Coffea robusta.
L. Coffea liberica.
than those of arabica. (See Illustration II, A RL.) This fact is in
accordance with previous findings and constitutes a means to distinguish
Robusta coffee from other varieties.
Stone cells—The stone cells represent sclerenchyma fibers or scler-
enchyma cells present in the silver skin. Their length may reach,
according to Hartwich, 700 microns. A few measurements have shown
sclerenchyma fibers about 500 microns in the furrow of the bean and
750 microns on the convex side of the bean. A tabulation of data
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 279
given in literature, as well as those found by the authors, is given in
Tables 3 and 4.
From these results, and especially from the writers’ detailed findings,
the following is evident:
The sizes of stone cells vary markedly in the furrow of the cotyledon
from those of the convex side of the beans. The cells of Coffea liberica
appear to differ in all particulars sufficiently from both Coffea robusta
and arabica to enable ready differentiation. The sclerenchyma cells of
Coffea robusta differ only comparatively slightly from Coffea arabica.
The sizes are about the same, especially as far as maximum length is
concerned. The cell wall is a little thinner in the case of Coffea robusta
cells, and the ends of the cells are more pointed. Further work on other
varieties of the group robusta, as well as of the species arabica, will have
to be done before a final statement can be made as to the usefulness of
the sclerenchyma cells of the seed coat for the purpose of differentiation.
PART II. CHEMICAL CHARACTERISTIGS.
Chemical analyses of seven samples of Robusta coffee were made,
and the results are given in Table 5. The origin of these samples is
also given in the table. For the sake of comparison, analyses of other
varieties of coffee, some of which were taken from the literature, are
included. Absolute ether was used for the determination of fatty
material instead of petroleum ether, as this had previously been used
by one of the authors on other varieties with which comparison is made.
The Power-Chesnut method, page 271, for caffeine was used for the
determination of this constituent.
The comparison with other varieties of coffee shows, in general, that
the ether extractives are lower in Robusta than in other varieties, and
that the caffeine is higher than that of South American varieties as
represented by the kinds listed.
The sample of Robusta obtained from the San Francisco Exposition
was subjected to the Power-Chesnut procedure for caffeine. The
crude residue was dissolved in 5 cc. of 0.2 N sulfuric acid. A sufficient
amount of Wagner’s reagent was added to precipitate the caffeine
periodide. The precipitate was dissolved in sodium thiosulfate solu-
tion and the solution extracted with chloroform. After evaporation of
the chloroform a nearly white residue was obtained. This residue had
a melting point of 228.5°C. (uncorrected).
The test described by Mulliken! for the specific characterization of
caffeine, which gives the uncorrected melting point of caffeine as 229.3°
to 30.3°C., was made. The derivative CsH,,O.N,HgCl. was obtained,
similarly to one from a sample of Merck’s caffeine which had been re-
crystallized from water and dried. The mercury complex obtained
1S. P. Mulliken. A Method for the Identification of Pure Organic Compounds. Ist ed., 1916, 2: 215.
280 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
Tas
Character istics of sclerenchyma
(General
MAXIMUM MAXIMUM AVERAGE AVERAGE
AUTHORS AND ANALYSTS
LENGTH WIDTH LENGTH WIDTH
Coffea arabica: microns microns microns microns
C. Hartwich* 700 51 520 Roce
A. E. Vogl7 700 45 300 36
A. L. Wintont 1000+ 50 wenn a5h..
J. Moeller§ 800 45 et Roki
C. Hartwich** ft 730 65 oe 35
R. G. Capentt 700 43 400 35
330 35 250 25
Coffea robusta:
C. Hartwich* 700 SS chs opie oes
R. G. Capenft 750 35 300 22
500 32 200 25
Coffea liberica:
C. Hartwich* tt 860 60.2 700 43
960 60.2 700 51.6
C. Hartwich §§ 880 51.2 660-760
R. G. Capenft 650 60 400 40
310 75 300 56
*A. Beythien, C. Hartwich, and M. Klimmer. Handbuch der Nahrungsmittel-Untersuchung. 1913-1915,
2: 304, 307, 309.
TA. E. Vogl. Die Wichtigsten Vegetabilischen Nahrungs und Genussmittel. 1899. 299.
tA. L. Winton. The Microscopy of Vegetable Foods 2nd ed., 1916, 432.
§J. Moeler. Mikroskopie der Nahrungs und Genussmittel. 1905, 406.
**C. Hartwich. Die Menschlichen Genussmittel. 1911, 278.
ttConvex surface.
ttConvex surface for first set of determinations; furrow for second set.
§§C. Hartwich. Schweizerische-Wochenschrift fur Chemie und Pharmacie. 1896, 475.
from the known caffeine had a corrected melting point of 250.8°C.,
while that obtained from the caffeine separated from the Robusta coffee
was 250.2°C. A mixture of the two mercury salts gave a melting
point of 250.5°C. Mulliken gives 251°C. as the melting point of the
mercury complex. This confirms the assumption that the product
obtained by the Power-Chesnut method and reported as caffeine was
practically pure caffeine.
COMMERCIAL DATA.
Condition and quality —A sample of Robusta coffee grown in Java,
obtained from the Netherlands Exhibit, San Francisco Exposition,
1915, represented coffee very fair in appearance. The beans were of a
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 281
LE 3.
cells of silverskin (seed coat.)
data.)
MAXIMUM MINIMUM AVERAGE
MINIMUM MINIMUM THICKNESS THICKNESS THICKNESS
LENGTH WIDTH OF CELI OF CELL OF CELL pe TS
WALLS WALLS WALLS
_ microns microns microns microns microns
Recor oe 15 46
75-90 15 aeae Puc Rt
100- 15 ie eee SEH Great variation in thick-
ness of cell walls.
70 15 hes eo es
90 one Bh ys ers 10-12 Cells usually longer and
thicker on convex sur-
{ face.
210 13.5 13.5 7 8
175 13.5 10 4 8
Pre aes lo Aone ae: Cell walls stightly thinner
95 13.5 13.5 Di, 5.4 and ends more pointed
80 13.5 10.8 Pf 5.4 than Arabica.
Walls thinner than
Arabica.
250 30 18.5 8 13.5
210 35 19 8 \ 13.5
high grade, evidently carefully cleaned and uniform. The size, as
pointed out before, was larger than other samples of Robusta. The
color of the seeds was light yellowish brown, and not greatly different
from a sample of genuine Java coffee which came to the writers’ atten-
tion at a previous time.
Samples collected by inspectors in different States of the United
States were generally of fair quality. The seeds on the average, how-
ever, were rather small and not so uniform in appearance as might
have been desired. With the exception of one or two, the samples
contained only few imperfections and consequently graded above No. 8,
representing the lowest grade of coffee accepted by the New York
Coffee Exchange. The samples representing the two exceptions were
evidently very poorly cleaned and, judging from a casual examination,
would possibly not have passed Grade 8.
Economic significance.—Robusta coffee, at first, was not greatly
valued, inasmuch as the beans were small and irregular and gave the
market product an inferior appearance. Gradually, however, its good
282 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TABLE
Characteristics of sclerenchyma cells of
(Detailed
(Analyst, R.
Coffea arabica*
THICKNESS
VARIETY ae wane OF CELL VARIETY
OF CELL OF CELL
WALL
microns microns microns
Mocha (convex surface) 700 30 4-5.4 Java
Mocha (convex surface) 510 35 8-16 Java
Mocha (convex surface) 360 27 10.8-13.5 || Java
Mocha (convex surface) 400 32 8 Java
Mocha (convex surface) 270 35 5.4 Java
Mocha (convex surface) 210 43 8 Java
Mocha (convex surface) 273 40 8 Java
Mocha (convex surface) 350 30 8-13.5 Java
Mocha (convex surface) 675 32 5.4 Java
Mocha (convex surface) 450 27 5.4 Java
Mocha (furrow) 200 13.5 4.5-6.7 Sumatra, (convex)
Mocha (furrow) 260 24 5.4-8 Sumatra, (convex)
| |] ||| Sumatra, (convex)
Sumatra, (convex)
Java (furrow) 330 27 5.4-10 Sumatra, (convex)
Java (furrow) 175 35 5.4-10 Sumatra, (convex)
| —|——————_ || Sumatra, (convex)
Sumatra, (convex)
Bourbon Santos 320 13.5 4.5-6.7 Sumatra, (convex)
Bourbon Santos 300 24 5.4-8
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Sumatra (furrow)
Unnamed sample
n (convex surface)
ss (furrow)
Unnamed sample
s (convex surface)
“ (furrow)
Unnamed sample
es (convex surface)
nS (convex surface)
Y (convex surface)
*Stone cells located in direction to longer axis. Lumen and cell walls not easily differentiated. Piths
long and stretched. Ends pointed. Cells more irregular in shape in furrow.
{Stone cells occur usually in groups of 2, lying in one axis. Lumen and cell walls easily differentiated.
Piths round or oval. Cells more irregular in shape in furrow.
tGroups of stone cells quite irregularly mixed. Lumen and cell walls easily differentiated. Piths
round or oval. Cell walls much thicker where piths are numerous.
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 283
4.
silver skin (seed coat.)
observations.)
G. Capen.)
Coffea robusta} Coffea libericat
LENGTH WIDTH THICENESS =. LENGTH WIDTH pe
OF CELL OF CELL OE'CELL Vere OF CELL OF CELL OPICELE
WALL WALL
microns microns microns microns | microns microns
410 33 13.5 Native (convex surface) 600 35 il
130 21 6-8 Native (convex surface) 530 35 11
200 35 5.4 Native (convex surface) 250 38 11
200 24 5.4 Native (convex surface) 300 46 13.5
115 26 5.4 Native (convex surface) 300 40 8-13.5
190 30 4 Native (convex surface) 530 49 13.5
260 16 5.4 Native (convex surface) 540 60 13.5
300 27 5.4-13.5|| Native (convex surface)| 650 46 8
350 32 5.4-16 |— -—£—____
300 22 5.4
Native (furrow) 235 54 13.5-16
Native (furrow) 300 35 8-13.5
270 24 Native (furrow) 250 67 16-19
200 22 Native (furrow) 290 60 13.5-19
190 22 Native (furrow) 200 50 13.5
750 32 Native (furrow) 310 56 13.5
160 19 Native (furrow) 285 56 13.5
220 19 Native (furrow) 250 57 13.5-16
220 22 Native (furrow) 210 54 13.5
135 19 Native (furrow) 200 75 16
95 19
Venezuela 390 30 13.5
500 13.2-29 | 4 Venezuela 310 46 13:5
80 13.2 5.4 Venezuela 430 43 13.5
100 21 5.4 Venezuela 300 32 13.5
130 21 5.4 Venezuela 270 43 13.5
350 30 10.8 Venezuela 420 40 13.5
160 16 5.4 Venezuela 430 40 13.5
160 32 5.48.1 —
220 21 8.1
85 13-27 5.4 180 46 13.5
== 135 48 13.5
150 54 13.5
375 19 95 46 13.5
300 19-24
375 19
300 19
450 27
480 27
420 19
284 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
TABLE 5.
Comparison of the analysis of Robusta coffee with other varieties of coffee.
(Results expressed as per cent by weight.)
MOISTURE | ABSOLUTE COLD MOISTURE-FREE EASts
KIND OVEN AT ETHER WATER Uae
105° C* | extract | exTRact* Kee Ether Water Caffeine
extract extract
Robusta
Raw t 8.15 9.79 27.92 1.13 10.66 30.40 1:23
Rawt 8.09 8.65 27.20 1.79 9.41 29.60 1.95
Roasted 6.14 7.09 21.03 2.04 7.55 22.40 JAZ
Robusta
Rawt 7.02 9.14 28.56 1.95 9.83 30.72 2.10
Roasted 5.65 10.77 23.54 1.92 11.41 24.95 2.03
Robusta a
Rawt 7.65 7.53 27.79 1.66 8.15 30.09 1.80
Roasted 5.55 9.64 22.41 1.97 10.21 23.73 2.09
Java roasted § 3.38** | 12.81f} | 23.08 1.30 13.26 23.89 1.35
Java Arabica
Rawtt 11.24 13.63 33:02 1.16 15.36 37.76 i133]
Roasted 5.64 14.20 27.40 Uebyf 15.05 29.04 1.66
Java Liberica
Rawtt 11.40 12.19 35.16 1.59 13.76 39.68 1.79
Roasted 3.98 13.13 34.17 2.19 13.67 35.58 2.28
Mocha roasted § 3.47** | 14.83t} | 22.82 ENS 15.36 23.64 1.19
Porto Rico roasted§| 1.31** | 13.49}{ | 22.89 1.30 13.92 23.62 1.34
Rio No. 4
Raw$§§ 5.92 14.54 30.49 1.08 15.45 32.41 Vas
Roasted 3.05 14.43 29.98 1.24 14.88 30.92 1.28
Rio No. 7
Raw§§ 5.85 12.85 21.62 1.03 13.65 22.96 1.09
Roasted 3.94 14.05 22.06 1.31 14.63 22.96 1.36
Santos roasted § 1.53** | 14.09f} | 21.74 1.18 14.67 22.63 1.23
Victoria
Raw§$§ 5.88 14.19 27.45 0.87 15.08 29.16 0.92
Roasted 2.88 15.37 22.06 1.09 15.83 22.71 1.12
*Assoc. Official Agr. Chemists, Methods. 2nd ed., 1920, 269.
tFrom Netherland’s East Indian Exhibit, San Francisco Exposition, 1915.
tCollected by food and drug inspectors from coffee roasters.
§Average of 3 samples analyzed by H. C. Lythgoe. U. S. Bur. Chem. Bull. 90: (1905), 43.
**Water oven 3 hours at 100° C.
ttPetroleum ether extract.
ttAnalyzed by W. L. A. Warnier, Pharm. Weekblad’, 1899, 36th year, No. 13; Z. Nahr. Genussm., 1900,
32 255;
§$Analyzed by H. A.Lepper. Reported by H. M. Loomis, J. Assoc. Official Agr. Chemists, 1920, 3: 502.
qualities were recognized; namely, its early bearing, prolific yields,
resistance to the coffee blight, leaf disease (Hemileia vastatrix), and its
comparative independence of climatic and soil conditions.
Yield per acre.-—Cramer' reports that a crop of over 1520 pounds per
acre may be expected under favorable conditions for Coffea robusta,
and more than 4000 pounds for Coffea quillou, which is often included
in the Robusta group.
1 Tea and Coffee Trade Journai, 1918, 35: 417, 420.
a C6 eo
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 285
Extent of cultivation —The extent to which Robusta coffee has, within
recent years, been grown in Java, may be seen from Table 6, which
also gives data as to yields of Coffea arabica and liberica:
TABLE 6.
Production of coffee in Java*.
YEAR ARABICA LIBERICA ROBUSTA
kilos kilos kilos
1910 4,552,000 4,146,000 1,861,000
1911 6,177,000 3,661,000 7,666,000
1912 11,631,000 3,339,000 15,557,000
1913 4,555,000 3,123,000 18,207,000
1914 11,941,000 2,227,000 34,268,000
*Philippine Agri. Rev., 1916, 9: 120.
Further interesting data concerning the production of the different
varieties for the years 1918, 1919, and 1920, showing the greatly pre-
dominating growth of Coffea robusta are tabulated in an article by
Fowler'. In the same article the author states the following with
regard to the acreage used for the cultivation of coffee:
According to statistics issued in September, 1919, by the Dutch East Indies Goyern-
ment, there were 144,663 hectares (357,469 acres) planted to coffee in the Dutch East
Indies. Of this area 120,910 hectares (298,774 acres), representing 833 per cent of the
total, were in Robusta; 8,005 hectares (19,780 acres), or 53 per cent, in Java (Arabica);
6,567 hectares (16,228 acres) or 43 per cent, in Liberica; and the remainder, 9,181 hec-
tares (22,687 acres) in various minor varieties.
Grading.—According to Trade Commissioner Fowler?, fermented beans
in Robusta, called ‘“‘stinkers’’ by the trade, have given Robusta coffee a
bad name in the American market. A first requisite is that this grade
shall be entirely free from these defective beans. One-half per cent of
broken and black beans are allowed in the grades exported to the United
States. “‘Export quality” which is the only grade exported is “‘double
picked”. y
Extent of importation.—From an importer of Robusta coffee it was
learned that during the year 1919 approximately one million bags (about
136,000,000 pounds) of Robusta coffee were imported into the United
States and it was prophesied that the amount will be still larger in
1920. The coffee is used, as far as can be learned, especially in the
Western and Middle Western States.
Utilization.—Robusta coffee is used as such alone, or is blended with
South American or other varieties of coffee. Some men in the coffee
1 Tea and Coffee Trade Journal, 1920, 39: 300.
2 Commerce Reports, November 11, 1920, 682,
286 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
trade consider the use of Robusta coffee as a filler if blended with other
varieties; this opinion, again, is not general.
Price-—With regard to the price, the following quotations which
indicate that the coffee, while not a very high-priced product, has a
distinct and appreciable market value, have been taken from the litera-
ture and from trade statements: “$25 per 100 kilograms’’. ‘‘Washed
939
Robusta Coffee, quoted at 19+ cents, and Santos at 243 cents?’.
Flavor and taste.—Of interest is the discussion in literature, as well
as the trade opinion, concerning the flavor and taste of Robusta coffee.
Before quoting a few detailed statements, it may be said that there is
considerable difference of opinion; some consider the flavor and taste
very desirable, others consider both quite inferior. It is evident that
the degree of roasting and the preparation of the coffee as a beverage
have considerable influence, and in order to bring out the cup quality
of Robusta coffee it may be necessary to modify the preparation of the
coffee for drinking, in order to get the best results. In Java, a con-
centrated cold water extract of the Robusta coffee is made by means of
percolators. This extract is served with hot milk.
Trade opinion in America.—Of further interest is a statement pub-
lished in 1912, concerning a decision of the New York Coffee Exchange’:
In February 1912 an important decision was taken by the Board of Managers of
the Coffee Exchange of the City of New York who decided in a special meeting to
boycott the robusta from the American market.
This measure seems to have been a consequence of the anxiety of coffee merchants
in view of the possibility that robusta coffee, if tendered for delivery on a contract on
the exchange, might have to be accepted in such a contract, while it is considered an
undesirable property owing to its status as a poor seller. (9th Annual Report of the
Nederland Chamber of Commerce in America.)
Certainly the unfavorable opinion about robusta, which the American coffee mer-
chants volunteer in their reports, is quite different from the opinion of the European
experts, and it is very probable that they only regard the robusta as a dangerous com-
petitor of the Santos coffee, over which the American merchants have a control, while
the robusta imports are not under their control.
Ukers* and Salak® pointed out that the New York Coffee Exchange
considered Robusta coffee as ‘‘a practically worthless bean”’.
Opinion of coffee dealers —The following statements, made by repre-
sentatives of the American coffee trade, taken at random, illustrate the
present contradictory attitude: |
1 Philippine Agri. Rev., 1916, 9: 122.
2A. L. Sullivan. (Private communication.)
* Agri. Bull. Federated Malay States, 1913, 1: 257.
4 Tea and Coffee Trade Journal, 1912, 22: 227.
5 Tbid., 1915, 29: 223.
1921] VIEHOEVER-LEPPER: ROBUSTA COFFEE 287
It is a neutral coffee which can be used in a blend with other coffees, since it will
not affect the flavor.
Has not the value we desire in our coffee.
It is tasteless and bodyless.
Should be taken out and dumped in the Chesapeake Bay.
Really better than low grade Santos or Rio. If properly selected it is a very fair
coffee, but like some others, there are all grades, some not worth anything.
Fancy in style and cup quality.
Robusta has been tested out and has wonderful cup value.
Robusta has no objectionable features like Rio and Santos.
Low grade Robusta (unwashed) was found superior to low grade Santos.
Robusta coffee has real value of its own, and should stand on this.
It is a good coffee, sweet and mild, better than Rio. It is superior to Nos. 6 and 7
of inferior varieties.
I am a firm believer in Robusta coffee. It has great cup value and is better than
Rio, Victoria, and Central American coffees.
Quotalions from literature—The following quotations are included,
since they give the opinion, mainly, of men who have given extensive
attention to Robusta coffee in regions where it grows:
While in the drying house the coffee must be often moved so as to get a regular dry-
ing. Coffee so prepared and dried keeps its bluish color long and has a good flavor.
Must be heated and ground in a manner somewhat different from other coffees.
Experts are inclined to put it nearly on a level as to quality with best Santos'.
Its one defect is that it is not equal in quality to the better grades of the other types
and therefore commands a lower price than the Arabian and Liberica?.
The appearance of the average marketable Robusta is not very beautiful; the beans
are small and irregular, and the average product shows little uniformity.
There are, however, great differences between the many different types of Robusta.
Some of them have comparatively large beans, larger even than Arabica, others again
have very small ones.
As regards the quality, though being inferior to Java-Arabica, the taste is generally
considered to be good and superior to the ordinary Arabica sorts, as Santos.
It is objected that the berries of the Robusta group and of other African coffees
are small in size and inferior in flavor; but the continually increasing quantities of
these coffees sold in Holland, and the satisfactory prices they fetch show that the
public is beginning to appreciate them. No objections will be made to the size of the
berries when by means of careful cultivation and especially of right preparation, a
coffee is obtained equal in flavor to the (old) Java and Arabian coffee’.
According to Salak* the quality of well prepared Robusta coffee is
approximately that of middling Arabian coffee.
The writers have carried out a number of cup tests, made as is custom-
ary in the coffee trade, of various samples of Robusta coffee. Even
though the beverages thus obtained were not made according to the
method followed in the Dutch East Indies, the results as to the quality
of taste and flavor of Robusta coffee were distinctly favorable.
Ji Dept. Agri. Federated Malay Slales, Bull. 7: (1910), 5.
2 Philippine Agri. Rev., 1916, 9: 123.
2 Ibid., 1915, 8: 46.
* Tea and Coffee Trade Journal, 1915, 29: 223.
288 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
SUMMARY.
The time when coffee could be limited to beans obtained from plants
of Coffea arabica and Coffea liberica has passed. Other species, with
qualities which make them desirable, even in preference to the well
reputed named ones, have been discovered and cultivated. Among
them, the species or group of Coffea robusta, has attained a great eco-
nomic significance and is grown in increasing amounts. While it has,
as reports seem to indicate, not as yet been possible to obtain a strain
that would be as desirable in flavor as the old “‘standard”’ Coffea arabica,
well known as Java or “Fancy Java’’ coffee, its merits have been estab-
lished.
The botanical origin is not quite cleared up and the classification of
the varieties belonging to the Robusta group deserves further study.
Anatomical means of differentiating Robusta coffee from other species
or groups may be applied as distinctly helpful. It appears that the
length of the embryo and the relation in size of cotyledon to hypocotyl,
the folding of the endosperm, if recurved and showing a hook, and to
some extent also the structure of the stone cells can be used as diag-
nostic characteristics in the identification of Rebusta coffee. The
seeds, on an average, are rather small, but may also attain fair sizes.
As is usual in most of the coffee species, caffeine is present. The
amount appears to be, on an average, somewhat larger (even exceed-
ing 2.0 per cent) than in other South American coffee species. In no
instance, however, did the amount exceed the maximum limits observed
in coffee in general.
The ether extractives were lower in Coffea robusta than in the other
varieties named in Table 4. Further data on Robusta coffee relative
to moisture, cold water extract, etc., were also determined, but did not
show any marked difference from the other coffees examined.
Due to its rapid growth, early and prolific yield, resistance to coffee
blight, and many other desirable qualities, Coffea robusta has established
‘its own’. In the writers’ judgment, Robusta coffee deserves con-
sideration and recognition.
REPORT ON TEA.
By E. M. Battery (Agricultural Experiment Station, New Haven,
Conn.), Referee.
A study of methods for the determination of caffeine in tea led to
the following recommendation last year!:
That the modified Stahlschmidt method, as it now appears tentatively, with the
exception that the caffeine residue be dried at 100°C. instead of 75°C., be made official
for the determination of caffeine in tea.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 538.
1921] BAILEY: REPORT ON TEA 289
Attention was also called to the work of Power and Chesnut! and it
was voted that the referee on tea consider this method in his work
this year. This suggestion has been carried out and the method, with-
out material change, has been found to be very satisfactory, yielding
caffeine of a high degree of purity. In addition, the Stahlschmidt
method has been improved so that caffeine of a higher degree of purity
than before is obtained. A new method has been evolved, which com-
bines the most desirable points of the Power-Chesnut and the Stahl-
schmidt methods, which is shorter than either of those methods and
which gives equally satisfactory results.
COLLABORATION.
The work this year has been done with the collaboration of R. E.
Andrew and C. E. Shepard, Agricultural Experiment Station, New
Haven, Conn., and H. A. Lepper, Bureau of Chemistry, Washington,
DeGr
FURTHER STUDY OF METHODS FOR THE DETERMINATION
OF CAFFEINE.
Improved Stahlschmidt Method.
Since it was noted in the referee’s report last year that caffeine ob-
tained by the Fendler-Stiiber method was of a slightly greater degree
of purity than that yielded by the Stahlschmidt method it was thought
that the latter method might be improved by introducing some modi-
fication to further purify the caffeine residue. The use of a dilute
solution of potassium permanganate for this purpose in the case of
coffee has been shown to result in a slight loss or destruction of caffeine.
Therefore, it was suggested by the writer and Shepard that dilute po-
tassium hydroxide might be used for the purpose. This procedure is
used by Power and Chesnut who have shown that no loss of caffeine
results from the treatment and the writer has further tested this point
as follows:
A small quantity (0.2 gram) of caffeine (99.4 per cent pure) was dissolved in 100 cc.
of chloroform and the solution shaken in a separatory funnel with 5 cc. of 1% potassium
hydroxide. After allowing the liquids to separate the chloroform was drawn off, the
aqueous solution in the separatory funnel washed with chloroform in two portions of
10 cc. each, and these washings added to the main extract. Most of the chloroform
was then removed by distillation, the residual portion transferred to a small tared
flask, evaporated, dried at 100°C. and weighed.
Caffeine taken, 0.2000 gram; found, A, 0.1991; B, 0.1999.
By treating the combined chloroform extracts, as obtained in the
modified Stahlschmidt method, with 5 cc. of 1 per cent potassium
1J. Am. Chem. Soc., 1919, 41: 1300.
1 J. Assoe. Official Agr. Chemists, 1921, 4: 526.
290 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
hydroxide, caffeine residues of a high degree of purity are obtained as
shown by Table 1.
TABLE 1.
Purification of caffeine by treatment with polassium hydroxide.
WITHOUT POTASSIUM HYDROXIDE WITH POTASSIUM HYDROXIDE
DESCRIPTION OF TREATMENT TREATMENT
SAMPLE
By weight From nitrogen By weight From nitrogen
per cent per cent per cent per cent
Black tea (4) 2.96 PTE 2.83 2.81
ysier als 2.89 2.87
Green tea (5) 1.86 1.73 1.65 1.59
The caffeine residues so obtained were practically free from color and
their purity is further indicated by the close agreement between results
for caffeine by weight and from nitrogen.
Power-Chesnul Method).
Extract 10 grams of material for 8 hours in a Soxhlet apparatus with hot 95% alco-
hol. Add the alcoholic extract to a suspension of 10 grams of heavy magnesium oxide
in 100 cc. of water, rinse the flask with a little hot water, and add the rinsings to the
mixture. Allow the mixture to evaporate slowly on a boiling water bath, with fre-
quent stirring, until the alcohol is removed and a nearly dry powdery mass is obtained.
Transfer the mass to a smooth filter by means of a sufficient amount of hot water,
cleaning the container thoroughly. Wash the material on the filter with successive
portions of hot water until the filtrate measures 250 cc. Add 10 ce. of 10% sulfuric
acid to the filtrate contained in a flask of suitable size, place a funnel in the neck of the
flask, boil cautiously until danger of frothing is passed and continue active boiling for
30 minutes. Allow the solution to cool and filter into a separatory funnel through a
double moistened filter and wash the flask and filter with small portions of 0.5% sul-
furic acid. Shake the clear acid filtrate with 6 successive 25 ec. portions of chloroform,
collecting the several extracts in a second separatory funnel. Treat the combined
chloroform extracts with 5 cc. of a 1% solution of potassium hydroxide and allow the
chloroform to completely subside. Draw off the chloroform into a suitable flask,
filtering through a dry paper or pledget of cotton inserted in the stem of the separatory
flask. Wash the alkaline liquid remaining in the separatory funnel with two portions
of chloroform, also washing the filter if used, and unite the washings with the main
bulk of chloroform solution. Distil the solvent to a small volume, transfer to a tared
beaker, evaporate to dryness, further dry for 1 hour at 100°C., cool and weigh.
To test the purity of the residue, determine nitrogen therein and calculate caffeine
by the factor 3.464.
The authors have shown: (1) That extraction of caffeine from the
material under examination is complete; (2) that no loss of caffeine
results from the treatment with magnesia, provided the same is free
1J, Am. Chem. Soc., 1919, 41: 1300,
1921) BAILEY: REPORT ON TEA 291
from appreciable amounts of sodium carbonate; (3) that no loss results
from boiling the aqueous solution of caffeine with dilute sulfuric acid;
and (4), that no loss results from the treatment of the chloroform solu-
tion of caffeine with dilute potassium hydroxide. The writer has
corroborated this last point by an experiment previously cited, page 289.
Results by this procedure, compared with those by the Stahlschmidt
method as modified this year, are shown in Table 2.
TABLE 2.
Comparison of the Stahlschmidt and the Power-Chesnut methods for caffeine in tea.
STAHLSCHMIDT METHOD POWER-CHESNUT METHOD
DESCRIPTION OF
SAMPLE
By weight From nitrogen By weight From nitrogen
per cent per cent per cent per cent
Black tea (4) 2.83 2.81 3.06 2.99
2.89 2.87 3.05 3.03
2.86* 2.84* 3.05 2.95
Green tea (5) 1.64 1.63 1.61 155
1.65 1.59 1.69 1.60
*Acid hydrolysis modification.
The figures by the two methods are in substantial agreement and
the caffeine residues are of about an equal degree of purity. In the
Power-Chesnut method the aqueous solution of caffeine is treated with
dilute sulfuric acid to hydrolyze possible saponin complexes and it was
thought that the slightly higher results in the case of Sample 4 might
be due to this feature of the method. Accordingly, the Stahlschmidt
method was repeated, introducing this acid hydrolysis, but the results
showed no increase in caffeine yield. However, the authors regard
this step as important and it is no doubt a wise provision, although
the necessity for it may not be apparent in every instance. The method
possesses an advantage in that the use of lead and its subsequent re-
moval is avoided; but your referee is still of the opinion that, so far as
tea is concerned, boiling water is a better initial solvent since it extracts
caffeine completely and materially simplifies the subsequent procedure.
Proposed New Method.
It therefore occurred to the writer and R. E. Andrew to extract the
caffeine directly by boiling with water, in the presence of magnesia,
make up to volume, take an aliquot portion and proceed as in the
Power-Chesnut method, thus combining the best features of that
method and of the Stahlschmidt method.
A procedure was finally evolved as follows:
292 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 2
To 5 grams of material in a 500 cc. graduated flask add 10 grams of heavy mag-
nesium oxide and 200 cc. of distilled water. Boil gently over a low flame for 2 hours,
using a small bore glass tube 30 inches long as a condenser. Cool, dilute to volume
and filter through a dry paper. Take an aliquot portion of 300 cc., equivalent to 3
grams of original material, in an Erlenmeyer flask of 1 liter capacity, add 10 cc. of a
10% solution of sulfuric acid and boil until the volume is reduced to about 100 cc.
Filter into a separatory funnel, washing the flask with small portions of 1% sulfuric
acid, and shake six times with chloroform using 25, 20, 15, 10, 10, 10, cc. portions.
Treat the combined extracts with 5 cc. of a 1% solution of potassium hydroxide, when
the liquids have completely separated, draw off the chloroform layer into a suitable
flask or beaker. Wash the alkaline solution in the separatory funnel with two portions
of chloroform of 10 cc. each and unite the washings with the main bulk of extract.
Evaporate or distil off the chloroform to a small bulk, transfer to a tared flask, evap-
orate to dryness, and further dry in a water oven at 100°C. to constant weight.
If desired, transfer the residue thus obtained to a digestion flask with successive
small portions of sulfuric acid and determine nitrogen by the Kjeldahl method, calcu-
lating caffeine from nitrogen by the factor 3.464.
The results as compared with the improved Stahlschmidt method and
with the Power-Chesnut method are shown in Table 3.
TABLE 3.
Comparison of the Stahlschmidt, Power-Chesnut, and proposed methods for caffeine in lea.
STAHLSCHMIDT METHOD POWER-CHESNUT METHOD PROPOSED METHOD
DESCRIPTION OF
SAMELE r From a From 4 From
Byicieht nitrogen By weight nitrogen By weight nitrogen
per cent per cent per cent per cent per cent per cent
Black tea (4) 2.83 2.81 3.06 2.99 2.98 2.86
2.89 2.87 3.05 3.03 2.94 2.87
2.86 2.84 3.05 2.95 2.92 2.82
Nahe eae oat NOC 2.80* 2.75*
2.84* 2.80*
Green tea (5) 1.64 1.63 1.61 1.55 1.70 1.61
1.65 1.59 1.69 1.60 1.66 1.58
wife Mr eS “Sales LCC 1.66
1:57* 1.52*
1.62* 1.57*
Green tea (9) 2.09 1.94 2.12 2.01 2.14 2.08
Black tea (10) 2.71t 2.63 2.69 2.67 2.62 2.62
Black tea (12) 3.10F 2.96 3.20 3.12 3.00 2.93
Aes Bote Pach 3.15 3.03
3.12 2.99
*Results by H. A. Lepper.
+Not purified by treatment with potassium hydroxide.
The results obtained by the proposed method are in close agreement
with those obtained by the other two methods and the caffeine residues
are of an equal degree of purity. The time required is very much less
than in either of the other procedures.
1921] BAILEY: REPORT ON TEA 293
So far as results are concerned, there is little to choose among the
three methods. The Power-Chesnut method possesses a considerable
advantage over the Stahlschmidt method in that it avoids the use of
lead acetate. It also has a range of applicability which your referee
can not claim for the Stahlschmidt procedure; for example, the referee
on coffee has found the Stahlschmidt method unsatisfactory for the
determination of caffeine in that substance. It seems advisable to
adopt, as an official method, a procedure as widely applicable to the
determination of caffeine as possible, and at the same time to include,
under special subjects, any additional method of demonstrated merit
and usefulness as a tentative procedure. The Stahlschmidt method
with the modification made this year would be recommended as a
tentative method were it not for the very satisfactory showing made by
the simplified method herein proposed. This method merits further
trial by a larger number of analysts.
RECOMMENDATIONS.
It is recommended—
(1) That the modified Stahlschmidt method, as recommended last
year for adoption as official for the determination of caffeine in tea, be
not made official this year.
(2) That the Power-Chesnut method, page 290, be made official for
the determination of caffeine in tea.
(3) That the proposed method for the determination of caffeine,
page 292, be given further trial by a larger number of analysts with a
view to its adoption as a tentative method.
The meeting adjourned at 5:15 p. m. for the day.
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ANNOUNCEMENTS
Miss Nellie A. Parkinson has resigned from the Bureau of
Chemistry of the United States Department of Agriculture
to accept the position of Assistant to the Editor of the Journal
of Industrial and Engineering Chemistry. Miss Parkinson has
served for some time as associate editor of our Journal and
is well known to most members of the association. She
carries with her the best wishes of many friends for con-
tinued success in her new work.
Miss Marian E. Lapp has been selected to succeed Miss
Parkinson as associate editor.
It was with a distinct shock that we learned of the death of
Dr. William Frear, which occurred at his home in State
College, Pa., on January 7, 1922. Dr. Frear was one of the
oldest, most active and best known of the members of this
association. A biographical sketch in appreciation of his life
and work will appear in a later number of The Journal.
Board of Editors,
R. W. Batcom, Chairman.
R. E. Doouitrtte,
R. B. DEEMER,
C. B. Lipman. :
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THIRD DAY. |
WEDNESDAY—MORNING SESSION.
REPORT OF THE COMMITTEE ON EDITING METHODS OF
ANALYSIS!
-Your committee is pleased to report that during the past year the
methods, as revised to. November 1, 1919, have been published and
distributed to all subscribers. The difficulties attending the publication
of these methods have fallen almost entirely upon the secretary’s office,
but your committee has devoted considerable time to the final prepara-
tion of the manuscript for the printers and to the reading of proof.
Unfortunately, the first lot of galley proof, which included the first
three chapters of the methods and the greater part of Chapter XXX,
the reference tables, was lost in the mails. Additional copies of the
galley proof for Chapters I, II and III were later secured, but no proof
for the reference tables, with the exception of those for alcohol, was
received. A threatened strike of the printers also made it impossible
for your committee to be furnished with copies of the page proof before
final printing. However, the proof reading was looked after by J. A.
MacLaughlin of Dr. Alsberg’s office, and the committee desires to
accord to him its appreciation and thanks for his assistance during the
past year and also to Miss N. A. Parkinson who prepared the greater
part of thecopy for the printer but who, onaccount of the press of work
on The Journal, was unable to look after the proof reading.
It is to be expected that in a book of the size of the present edition of
the methods and especially with the difficulties attending its publication,
some errors would occur. Fortunately, these errors are not serious in
so far as any of the methods are concerned. Your committee has,
however, gone over the book very carefully and made a list of the errors
found, which list forms a part of this report.
Your committee also has prepared a list by chapters of the changes
and additions which were made to the Official and Tentative Methods
of Analysis at the 1919 meeting of the association. It will be recalled
that at the meeting in November 1919 it was decided not to incorporate
the changes and additions made at that meeting for the reason that
the manuscript was ready for the printer and it was feared that if it
were again revised the printing of the methods might be delayed. A
few of the changes which could be incorporated without altering the
chapter or paragraph numbers were inserted, however. These are
1 Presented by R. E. Doolittle.
297
298 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
noted in the committee’s report. The list of the 1919 additions and
changes is submitted for the information of the members of the associa-
tion and subscribers to the book of methods.
With the publication of the revised methods it would appear that the
work of your committee, which was appointed at the 1914 meeting for
the special purpose of revising Bureau of Chemistry Bulletin 107, has
been completed. The additions and changes made to the methods,
however, should be compiled each year for the information of the mem-
bers of the association and the subscribers to the book of methods. To
be of greatest value, this compilation should be prepared and published
immediately after the close of each annual meeting. While your com-
mittee feels that the work for which it was appointed has been com-
pleted, it respectfully recommends that the association provide for the
appointment of a permanent committee on editing methods of analysis
whose duty it shall be to compile the additions and changes made to
the official and tentative methods.
ERRATA IN OFFICIAL AND TENTATIVE METHODS OF
ANALYSIS".
PREFACE
Page iii, Line 20.—Change initials of Dr. Gascoyne from “J. W.”’ to “W. J.”
CONTENTS
Page x, Line 2.—Change “‘y’’ to “‘vii’’.
Line 2 from bottom of page-—Change ‘‘209”’ to “309”.
X. COLORING MATTER IN FOODS.
21 PROCEDURE.
Page 141, line 6.—Omit the word “Plum” after “Radish’’; insert commas after the
words “Cranberry” and “Cherry’’, making the line read: “Purple Grape, Cranberry,
Sloe, Cherry, Plum, Radish and Red Beet are described’’.
22 TABLE 10.
Page 143, line 18.—Change ‘“‘Xanthopyll” to ‘““Xanthophyll’.
BIBLIOGRAPHY.
Reference 5.—Change ‘“‘Thrum”’ to ““Thrun”’.
XXII. FATS AND OILS.
36 HALPHEN TEST.
Change “Halpen’’ to “‘Halphen’’.
1 Assoc. Official Agr. Chemists, Methods., 1920.
ae
1922] EDITING METHODS OF ANALYSIS 299
XXX. REFERENCE TABLES.
1 Munson AND WALKER’S TABLE.
Page 325, column 7, line 3 from bottom of page.—Change “140.0” to “144.0”.
Page 326, column 5, line 9—Change “196.7” to “106.7”.
Page 328, column 9, line 22.—Change “‘254.0” to “264.0”.
Page 331, column 4, line 10.—Change “‘226.7”’ to “226.1”.
Page 331, column 5, line 23.—Change “‘233.4” to “232.5”.
3 Densities of solutions of cane sugar at 20°C.
Page 341, column 5, line 3 from bottom of page-—Change ‘‘1.535791” to “1.535704”.
4 Corrections to be applied to results obtained by 3 when the specific gravity is obtained
at temperatures other than 20°C.
Page 342.—Delete this table as it is an earlier edition of 9, page 388.
5 GEERLIGS’ TABLE.
Page 343, column 6, line 16.—Change “16” to “‘0.0016”’.
Page 343, column 9, line 10 from bottom of page-—Change “1.7” to ‘‘0.7’’.
if ALcoHoL TABLE.
Page 356, column 11, line 10.—Change ‘‘81.12” to ‘82.12”.
8 Atconot TABLE.
Page 379, column 5, line 13 from bottom of page-—Change ‘‘27.73”’ to ‘26.73’.
10 Degrees Brix, specific gravity, and degrees Baumé of sugar solutions.
Page 389, column 2, line 25.—Change “1.00759” to ‘1.00758’.
Page 393, column 2, line 14 from bottom of page-—Change “1.17183” to “1.17185”.
TABLE OF INTERNATIONAL Atomic WeIGcHTs, 1917!.
Insert Table of International Atomic Weights, 1917, at end of tables.
INDEX
Page 401, line 29.—Change page “‘249”’ to “247”.
Page 404, line 10.—Change page “‘294’’ to “299”.
Page 404, line 12.—Change page “‘229”’ to “‘299”’.
Page 406, line 34.—Change “XV, 19”’ to “XV, 9, 10”.
Page 408, line 15.—Change page “113” to “133”’.
Page 408, line 10 from bottom of page-—Page number omitted. Insert ‘‘88’’.
Page 409, line 13 from bottom of page-—Change page “15” to “13”.
Page 410, line 10 from bottom of page-—Omit the words ‘alcohol’ and ‘‘extracts”’
and insert the words “and insoluble”’ after the word ‘“‘soluble”’, making the expression
read “soluble and insoluble in meat’.
Page 410, line 3 from bottom of page-—Change the word ‘‘products”’ to ‘extracts and
similar products”, making the expression read “insoluble, in meat extracts and similar
products”.
Page 413, line 11.—Change page “302” to “309”.
Page 417, line 21.—Change page “215” to “216”.
1 J. Am. Chem. Soc. 1916, 38: 2220.
300 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
1919 CHANGES AND ADDITIONS IN OFFICIAL AND TENTATIVE METHODS
OF ANALYSIS}.
I. FERTILIZERS.
2 PREPARATION OF SAMPLE.
The directions for sampling which appear in the close print in the
second paragraph were supplemented by instructions covering the
number of bags to be sampled as follows: }
Take cores from not less than 10 per cent of the bags present, unless this necessitates
cores from more than 20 bags, in which case take a core from 1 bag for each additional
ton represented. If there are less than 100 bags, sample not less than 10 bags. In
lots of less than 10 bags sample all bags.
The directions for sampling as adopted by the association, arranged
according to procedure, are therefore as follows:
Each official sample sent to the laboratory shall consist of at least a pound of the
material taken in the following manner: Employ a sampler that removes a core from
the bag from top to bottom. Take cores from not less than 10 per cent of the bags
present, unless this necessitates cores from more than 20 bags, in which case take a
core from 1 bag for each additional ton represented. If there are less than 100 bags,
sample not less than 10 bags. In lots of less than 10 bags, sample all bags. Pass the
entire sample submitted to the analyst through a 10-mesh sieve previous to its sub-
division for analysis.
Il. INORGANIC PLANT CONSTITUENTS.
The following methods for the determination of calcium and mag-
nesium were adopted as tentative methods. These methods have been
printed in the proceedings of the association.
CALCIUM.—TENTATIVE,
Remove 25 ce. of the solution, representing 0.5 gram of ash, and dilute to 200 cc.,
add a few drops of alizarine or methyl orange and make slightly ammoniacal. Add very
dilute hydrochloric acid (1 to 10) until the solution is just faintly acid, followed by
10 ce. of 0.5N hydrochloric acid and 10 cc. of 2.5% oxalic acid. Boil the solution and
add, with constant stirring, 15 cc. of a saturated solution of ammonium oxalate. Con-
tinue to heat until the precipitate becomes granular. Cool and add, with constant
stirring, 8 ec. of 20% sodium acetate solution, and allow to stand 12 hours. Filter,
and wash with hot water until free from chlorides. Dissolve the precipitate in hot,
dilute sulfuric acid and titrate with 0.1N potassium permanganate solution. In dis-
solving the precipitate it is best first to wash it off the paper into a beaker, and then to
dissolve the portion remaining on the paper with hot, dilute sulfuric acid. (1 ce. of
0.1N KMNO,=0.0028 gram CaO.)
1 Assoc. Official Agr. Chemists, Methods, 1920.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 392.
1922] EDITING METHODS OF ANALYSIS 301
MAGNESIUM—TENTATIVE,
To the combined filtrate and washings from the calcium determination, add 25 cc.
of strong nitric acid and evaporate to dryness. Take up with dilute hydrochloric acid
and make to a volume of about 100 cc. Add 5 cc. of a 10% sodium citrate solution
and 10 cc. of sodium hydrogen phosphate solution, or enough to precipitate all of the
magnesium. Add dilute ammonium hydroxide, with constant stirring, until the solu-
tion is faintly alkaline; then add about 25 ce. of strong ammonium hydroxide and set
aside in a cool place overnight. Filter and wash with 2.5% ammonium hydroxide.
Dissolve the precipitate in dilute hydrochloric acid and reprecipitate as before. Allow
-to stand for several hours, filter and wash free of chlorides with 2.5% ammonium
hydroxide solution, ignite and weigh as magnesium pyrophosphate.
III. WATERS.
52, 53 and 54 BARIUM.
The method for the determination of barium in waters was made an
official method. (Second and final presentation of the method for
action.) The method has been published in The Journal and also in
the Official and Tentative Methods of Analysis!.
60 and 61 BISMUTHATE METHOD.
The bismuthate method for the determination of manganese was
adopted as an official method. (Second and final presentation of the
method for action.)
The following method for the determination of iodine in the presence
of chlorine and bromine was adopted as a tentative method. The
method has been published in the proceedings’.
IODINE IN THE PRESENCE OF CHLORINE AND BROMINE—TENTATIVE,
REAGENTS.
(a) Sodium hydroxide and sodium carbonate solution—Dissolve 2.5 grams of sodium
hydroxide and 2.5 grams of sodium carbonate in water and dilute to 100 cc.
(b) Dilute sulfuric acid (1 to 10).
(Cc) Sodium hydroxide solution Dissolve 4 grams of sodium hydroxide in water and
dilute to 100 cc.
(d) Potassium permanganate solution.—Dissolve 10 grams of potassium permanga-
nate in water and dilute to 100 cc.
(€) 0.05N sodium thiosulfate solution —Dissolve 12.4 grams of recrystallized sodium
thiosulfate in 1 liter of water. This solution should be standardized against 0.05N
potassium dichromate.
DETERMINATION.
Take such a quantity of the brine or water as will contain not more than 0.1 gram of
iodine or more than 10.0 grams of total salts. Adjust the volume to 100-150 cc., add
a sufficient quantity of the solution of sodium hydroxide and sodium carbonate to
1J. Assoc. Official Agr. Chemists, 1920, 4: 86; Assoc. Official Agr. Chemists, Methods, 1920, 34.
2 [bid., 1921, 4: 380.
302 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
precipitate the calcium and magnesium. Boil, filter off the precipitate of calcium and
magnesium, and wash with hot water; introduce the filtrate into an Erlenmeyer flask,
adjust the volume to about 100 cc., neutralize with the dilute sulfuric acid and add
1 cc. of the sodium hydroxide solution. Heat to boiling, add an excess of the potassium
permanganate solution, about 0.5 cc. excess, continue heating until the precipitate
begins to coagulate and then allow to cool. Add sufficient 95% alcohol or hydrogen
peroxide to bleach the permanganate color and set the beaker on a steam bath. When
the precipitate has settled, filter and wash the precipitate with hot water. After
cooling, add 1-2 grams of potassium iodide, acidify with hydrochloric acid and titrate
with 0.05N thiosulfate. One-sixth of the iodine titrated represents the amount
originally present. (1 cc. of 0.05N thiosulfate solution =1.058 mg. of iodine.)
The reactions are as follows:
REACTIONS.
KI+2 KMn0O,;+H,0 =KIO;+2 KOH+2 Mn0O..
KIO;+5 KI+6 HC1=6 KC1+3 H,0+8 hk.
= I.+6 Na2S203 =6 NaI+3 NazS4O¢.
The following method for the determination of bromine in the presence
of chlorine but not iodine was adopted as a tentative method. The
method has been published in the proceedings’.
BROMINE IN PRESENCE OF CHLORINE BUT NOT
IODINE.
REAGENTS.
(a) Sodium sulfite and sodium carbonate solu-
tion.—Dissolve 4 grams of sodium sulfite and
0.8 gram of sodium carbonate in water and
dilute to 100 cc.
(b) Chromium trioxide crystals.
(c) Hydrogen peroxide solution (3%).
(d) 0.05N sodium thiosulfate solution.
APPARATUS.
A. B. Cc.
A. REACTION CYLINCER. The apparatus used consists of 2 Dreschel
B&C.ABSORPTION CYLINDERS. gas wash bottles, high form, joined as shown
E. RUBBER CONNECTIONS. in Fig. 1. An ordinary wash bottle may be sub-
stituted for C if desired.
DETERMINATION.
Evaporate the sample of water or brine, which should not be too acid, to dryness or
nearly so. Charge the reaction cylinder A, Fig. 1, by introducing glass beads to a
depth of about 1 inch, followed by 15 grams of solid chromium trioxide, and finally
enough glass beads to fill the cylinder half full. Add 20 ce. of the sodium sulfite and
sodium carbonate solution to the first absorption cylinder B and 5 cc. to the second C.
Dilute each to about 200 ce. Connect the three cylinders and draw a current of air
1 J. Assoc. Official Agr. Chemists, 1921, 4: 381.
1922] EDITING METHODS OF ANALYSIS 303
through slowly. Wash the sample into the reaction cylinder with water sufficient to
make about 25 cc. of solution. Aspirate until the contents of the reaction cylinder are
in solution and thoroughly mixed, then discontinue, close the inlet tube with a small
piece of rubber tubing and a clamp, and reduce the pressure in the apparatus slightly
by suction, in order to guard against any possible escape of bromine at the ground-
glass stopper. Allow to stand overnight, then aspirate with a rather strong current of
air (about 144-34 liter per minute) for 3 hours, adding 4 portions of 2 cc. each of the
hydrogen peroxide solution at 30-minute intervals. Stop the aspiration and evaporate
the contents of the two absorption cylinders nearly to dryness. Empty the reaction
cylinder, clean, and freshly charge with glass beads and 15 grams of chromium trioxide.
To the first absorption cylinder add 10 grams of potassium iodide dissolved in 200 ce.
of water, and to the second 3-4 grams in a like amount of water. Connect the ap-
paratus, draw through a slow current of air and transfer the contents of the evaporating
dish to the reaction cylinder by means of the small funnel, using 25 cc. of water. Aspi-
rate until all of the bromine is evolved (about 1 hour) and titrate the potassium iodide
solution with the thiosulfate. (One cc. of 0.05N thiosulfate=3.996 mg. of bromine.)
The reactions are as follows:
: REACTIONS.
2 CrO;+6 HBr=Cr:0;+3 H.0+3 Bro.
2 H.Cr0;+3 H.0:2 =Cr.03 +2 O.+5 H:0.
Na2SO; +2 Br+H:0 =2 HBr+ Na2SOx,.
The following method for the determination of free and albuminoid
ammonia in water containing sulfide was adopted as a tentative method.
The method has been published in the proceedings'.
FREE AND ALBUMINOID AMMONIA.—TENTATIVE.
(In samples containing sulfide.)
REAGENTS.
(a) 0.5N solution of sulfuric acid.
(b) SN solution of sodium carbonate.
(c) Ammonia-free water.
(d) Standard ammonium chloride solution.—Prepare as directed under 10 (Cc).
(@) Nessler reagent.—Prepare as directed under 10 (d).
(f) Alkaline potassium permanganale solulion—Prepare as directed under 10 (e).
DETERMINATION.
Place 500 cc. of the sample in a beaker or casserole, add 30 ct. excess of 0.5N sulfuric
acid solution. Boil the solution carefully until free of sulfide (about 20 minutes).
Add about 300 ce. of distilled water and 8 cc. of 5N sodium carbonate solution to a
distillation flask connected as described under 11, and distil until free from ammonia.
Cool, add the cooled sample which has been freed from sulfide, and proceed as described
under 11, beginning with “‘Distil into 50 cc. Nessler tubes”’.
IV. TANNING MATERIALS.
No changes or additions to these methods were made at the 1919
meeting.
1J. Assoc. Official Agr. Chemists, 1921, 4: 387.
304 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Vv. LEATHERS.
No changes or additions to these methods were made at the 1919
meeting.
VI. INSECTICIDES AND FUNGICIDES.
A method for the determination of total arsenic in magnesium arse-
nate! was adopted as an official method. (First presentation of the
method for adoption as official.)
A method for the determination of total arsenious oxide in magnesium
arsenate! was adopted as an official method. (First presentation of the
method for adoption as official.)
A method for the determination of total arsenious oxide in calcium
arsenate! was adopted as an official method. (First presentation of the
method for adoption as official.)
These methods should be inserted in the Official and Tentative
Methods of Analysis, after 36, in the following manner:
TOTAL ARSENIOUS OXIDE!.—TENTATIVE.
Proceed as directed under 33.
MAGNESIUM ARSENATE.
TOTAL ARSENIC.—TENTATIVE.
Proceed as directed under 27.
TOTAL ARSENIOUS OXIDE.—TENTATIVE.
Proceed as directed under 33.
VII. FOODS AND FEEDING STUFFS.
MOISTURE.
The following method for the determination of water by drying over
lime in vacuo without heat was adopted as a tentative method. The
method has been printed in the proceedings’.
Weigh 2 grams of the material into a suitable dish or crucible with a tightly fitted
cover. Place in a vacuum desiccator over about 400 grams of freshly powdered ignited
lime, and exhaust with a vacuum pump. After 24 hours, open the desiccator, forcing
the incoming air through concentrated sulfuric acid and make the first weighing. After
weighing, replace the dish in the desiccator and repeat the process until constant weight
is obtained. The lime should be changed on the third or fourth day and, with very
wet substances, once again near the end of the process.
The following method for the determination of water by drying over
calcium carbide in vacuo without heat was adopted as a tentative
method. The method has been printed in the proceedings’.
1 J. Ind. Eng. Chem. 1916, 8: 327.
2 J. Assoc. Official Agr. Chemists, 1920, 4: 247.
1922] EDITING METHODS OF ANALYSIS 305
Weigh 2 grams of the material into a suitable dish or crucible with a tightly fitted
cover. Place in a yacuum desiccator over about 400 grams of clean lumps of calcium
carbide, and exhaust with a vacuum pump. After 24 hours, open the desiccator, forcing
the incoming air through concentrated sulfuric acid and make the first weighing. After
weighing, replace the dish in the desiccator and repeat the process until constant weight
is obtained. The calcium carbide should be changed on the third or fourth day and,
with very wet substances, once again near the end of the process.
VIII. SACCHARINE PRODUCTS.
1 _ PREPARATION OF SAMPLE.
Directions for the preparation of samples of raw sugar for analysis
were adopted by adding to 1 (c) the following:
In the case of raw sugars, mix thoroughly, and in the shortest possible time, on a
watch glass with a spatula; when lumps are present, reduce them with a glass or iron
rolling pin; or mix thoroughly in the shortest possible time in a large, clean, dry mortar,
using a pestle to reduce lumps if present.
The following temperature formula for correcting the polarization of
raw sugars to 20°C. was adopted:
Normal raw cane sugar polarizations made at other temperatures than the standard
temperature of 20°C. may be calculated to the polarization at 20°C. by the following
formula:
P?0= Pt+0.0015 (Pt—80) (f—20), in which
Pt =the polarization at which temperature is read; and
i1=the temperature at which polarization is read.
When the percentage of levulose in the sugar is known, the following formula should
be used:
P20 = Pt+0.0003°S (t—20)—-0.00812°L (t—20) in which
Pt=the polarization at which temperature is read;
t=the temperature at which polarization is read;
S=the percentage of sucrose; and
L=the percentage of levulose.
The Baumé scale! (Modulus 145) of the Bureau of Standards was
adopted as the official Baumé scale of the association and all Baumé
tables and references thereto not in accordance with this scale were
eliminated from the methods of the association. The Committee on
Editing Methods of Analysis was authorized to make such changes in
the text of this chapter as were necessary to make this change effective.
These changes are as follows:
5 By Means of a Spindle.—Official.
This determination has been changed to read as follows:
The density of juices, sirups, etc., is most conveniently determined by means of the
Brix hydrometer. For rough work, or where less accuracy is desired, the Baumé
1U.S. Bur. Standards Circ. 44: (1918), 151.
306 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
hydrometer may be used. A table for the comparison of specific gravities at ee
and “~°, degrees Brix (per cent by weight of sucrose) and degrees Baumé, is given
under X XX, Table 10. The Brix spindle should be graduated to tenths and the range
of each individual spindle should be as limited as possible. The solution should be as
nearly as practicable of the same temperature as the air at the time of reading, and, if
the variation from the temperature of the graduation of the spindle amounts to more
than 1°, a correction must be applied according to the table under XXX, 9.
Before taking the density of a juice, allow it to stand in the cylinder until all air
bubbles have escaped and until all fatty or waxy matter has come to the surface and
been skimmed off. The cylinder should be large enough in diameter to allow the
hydrometer to come to rest without touching the sides. A table of specific gravities at
20°C. and of per cent by weight of sucrose, is given under XXX, 3. A table for com-
parison of specific gravities at 2° and “{S—, degrees Baumé (Modulus 145) and
degrees Brix (per cent by weight of sucrose) is given under XXX, 10.
If the sample is too dense to determine the density directly, dilute a weighed portion
with a weighed quantity of water, or dissolve a weighed portion and dilute to a known
volume with water.
In the first instance the per cent of total solids is calculated by the following formula:
Per cent of solids in the undiluted material= in which
S=per cent of solids in the diluted material;
W =weight of the diluted material; and
w =weight of sample taken for dilution.
When the dilution is made to a definite volume, the following formula is to be used:
=
Per cent of solids in the undiluted material = 4 in which
V=volume of the diluted solution at a given temperature;
D=specific gravity of the diluted solution at the same temperature;
S=per cent of solids in the diluted solution at the same temperature; and
W =weight of the sample taken for dilution at the same temperature.
If the spindle reading be made at any other temperature than 20°C. the results
should be corrected as directed under XXX, 9.
6 TABLE 7.
Eliminate this table and substitute therefor XXX, 9.
7 (b).—This paragraph has been corrected to read as follows:
(b) By specific gravity at *~°-—Proceed as directed under (€), the determinations
of specific gravity being made at ~4s~ instead of auc. Ascertain the corresponding
per cent by weight of sucrose from XXX, 10.
MAPLE PRODUCTS.
The following method for determination of the Canadian lead number
was adopted as a tentative method. The method has been printed in
the proceedings'.
CANADIAN LEAD NUMBER.—TENTATIVE.
REAGENTS.
Slandard basic lead acetate solution.—Boil 280 grams of dry basic lead acetate [VII,
13 (c)| with 500 ce. of water. When solution is complete except for a slight sediment,
pour off into a beaker or allow to cool in dish and dilute with recently boiled water
to a density of 1.25 at 20°C.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 437.
1922| EDITING METHODS OF ANALYSIS 307
DETERMINATION.
Weigh the quantity of the sirup prepared as directed under 50, containing 25 grams
of dry matter, transfer to a 100 cc. volumetric flask, cool to 20°C. and make up to the
mark. Pipet 20 cc. into a large test tube, add 2 cc. of the standard basic lead acetate
solution and mix. Allow to stand for 2 hours. Filter on a tared Gooch, having an
asbestos mat at least 3 mm. thick, wash four or five times with boiling water, dry at
100°C. and weigh. Multiply the weight of the dry precipitate by 20.
The following method for the determination of conductivity value
-was adopted as a tentative method. This method has been printed in
the proceedings’.
CONDUCTIVITY VALUE.—TENTATIVE.
Determination of the cell constant—Prepare 0.1,0.05 and 0.01N potassium chloride
solutions by dissolving respectively, 7.4560, 1.4912 and 0.7456 grams of pure, ignited
potassium chloride in water and making up to 1 liter at 18°C. In a 100 cc. beaker
place 60 cc. of the 0.01N solution, insert a Van Zoeren or other dipping electrode, bring
to 25°C. and measure the electrical resistance. Multiply the number of ohms found by
141.2. Rinse the electrode and beaker with the 0.05N solution, add 60 cc. of this
solution, measure its resistance at 25°C. and multiply by 276.8. Rinse with the 0.1N
solution, add 60 cc. of this solution, measure its resistance at 25°C. and multiply by
1289. Average the three results (which should agree within 1 per cent) and multiply
by 10°. i
DETERMINATION.
Weigh the quantity of sirup containing 22 grams of dry matter. Transfer to a
100 ce. volumetric flask with warm water, cool and make up to the mark. Measure
60 cc. of the solution into a 100 cc. beaker, insert a Van Zoeren or other dipping elec-
trode, bring to 25°C. (=0.1°) and measure the electrical resistance. Divide the con-
stant of the cell by the observed number of ohms and multiply the result by 10°.
IX. FOOD PRESERVATIVES.
No changes or additions to these methods were made at the 1919
meeting.
X. COLORING MATTERS IN FOODS.
No changes or additions to these methods were made at the 1919
meeting.
XI. METALS IN FOODS.
5 Gravimetric Method.
Adopted as an official method. (First presentation of the method for
action as official.)
6 and 7 Volumetric Method.
Adopted as an official method. (First presentation of the method for
action as official.)
1 J. Assoc. Official Agr. Chemists, 1921, 4: 435.
308 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
XII. FRUITS AND FRUIT PRODUCTS.
No changes or additions to these methods were made at the 1919
meeting.
XIII. CANNED VEGETABLES.
No changes or additions to these methods were made at the 1919
meeting.
XIV. CEREAL FOODS.
No changes or additions to these methods were made at the 1919
meeting.
XV. WINES.
No changes or additions to these methods were made at the 1919
meeting.
XVI. DISTILLED LIQUORS.
No changes or additions to these methods were made at the 1919
meeting.
XVII. BEERS.
No changes or additions to these methods were made at the 1919
meeting.
XVIII. VINEGARS.
1 PHYSICAL EXAMINATION.
Adopted as an official method. (First presentation of the method for
adoption as official.)
- ALCOHOL.
Adopted as an official method. (First presentation of the method for
adoption as official.)
XIX. FLAVORING EXTRACTS.
The following method for the determination of alcohol in lemon and
orange extracts! was adopted as an alternate official method. (First
presentation of the method for adoption as official.)
ALCOHOL.
Method II. —Tentalive.
(Applicable only to extracts consisting of oil, alcohol and water.)
Let S represent the specific gravity of the extract at 20°C./4° as determined under
17; 0 the specific gravity of the oil and p the per cent of oil found. Then 100-p will be
the per cent of the water-alcohol solution, the specific gravity of which, represented
by P, is calculated as follows:
s Op+P(100—p) 100.S—Op
, whence P=
100 i peer 100—p
1 J. Ind. Eng. Chem., 1909, 1: 94.
1922] EDITING METHODS OF ANALYSIS 309
The value of E, the alcohol equivalent of P,is obtained from X XX, 1 and gives the
per cent of alcohol in the alcohol-water solution. To find the per cent of alcohol in
the extract, apply the following formula:
Per cent by volume of alcohol in the extract = E (1-3).
The value of O for lemon extract may be taken as 0.85 and for orange extract as 0.84.
XX. MEAT AND MEAT PRODUCTS.
Page 210, NITRATES.
This heading was changed to read “Nitrates and Nitrites (calculated
as sodium nitrate)’’ and the method has been changed to provide that
the results be calculated to sodium nitrate instead of potassium nitrate.
The last sentence of 11 has accordingly been changed to read as follows:
One cc. of nitric oxide at 0°C. and 760 mm. pressure is equivalent to 0.0037935 gram
of sodium nitrate.
The following method for the determination of sugar was adopted
as a tentative method to be substituted for the former tentative method!.
This substitution has been made and the method printed in the 1920
edition of the methods’.
SUGAR.—TENTATIVE.
19 REAGENT.
Phosphotungstic acid solution Dissolve 100 grams of phosphotungstic acid in water
and dilute to 100 cc.
20 DETERMINATION.
Weigh 100 grams of the finely ground sample into a 600 cc. beaker, add 200 cc. of
water, heat to boiling and boil gently for 5 minutes. Stir the contents of the beaker
frequently during this and subsequent extractions to prevent lumping. (When several
samples are extracted at the same time a mechanical stirring device is practically a
necessity.) Remove the beaker from the flame, allow the insoluble matter to settle
and decant the clear liquid on an asbestos mat in a 4-inch funnel. Filter with the aid
of suction. Add 150 cc. of hot water to the residue in the beaker, boil gently for 5
minutes, let settle and decant the clear liquid as above. Repeat the operation and
finally transfer the contents of the beaker to the funnel, wash with 150-200 cc. of hot
water and press the meat residue as dry as possible. Transfer the contents of the filter
flask to an evaporating dish and evaporate on a steam bath to a volume of about 25 cc.,
but not to dryness. Transfer the extract to a 100 cc. volumetric flask, taking care
that the volume of liquid does not exceed 60 ce. Add 25-35 ce. of the phosphotungstic
acid solution, shake vigorously, let stand a few minutes for gas bubbles to rise to the
surface, make to volume, shake and either filter or centrifugalize. The use of a centri-
fuge is to be preferred since thereby a large volume of liquid is obtained. Test a portion
of the filtrate with dry phosphotungstic acid for complete precipitation. If an appre-
ciable precipitate forms, take an aliquot of the filtrate, add 5—10 cc. of the phospho-
1 Assoc. Official Agr. Chemists, Methods, 1916, 278.
2 Ibid., 1920, 213.
310 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
tungstic acid solution, make to volume, filter and test the filtrate for complete pre-
cipitation. The filtrate should also show not more than a slight reaction for creatinin
by Jaffe’s test.
Transfer 50 cc. of the clarified extract to a 100 cc. volumetric flask, add 5 ec. of con-
centrated hydrochloric acid and invert the solution as directed under VII, 14. Cool
the solution, neutralize to litmus, cool, make to volume and filter. To the filtrate add
sufficient dry powdered potassium chloride to precipitate the excess of phosphotungstic
acid, filter, test the filtrate for complete precipitation, and determine the reducing
sugar, as directed under VII, 25, ascertaining the amount of reduced copper, as
directed under VII, 29. Calculate the total sugar as dextrose.
If, when the clarified meat extract is boiled with Fehling’s solution an abnormal
reduction is obtained, 7. e., the solution turns yellow, brown, green or muddy in ap-
pearance instead of reddish-blue, the determination should be discarded, since incomplete
precipitation of the nitrogenous compounds, due to the use of insufficient phospho-
tungstic acid, is indicated.
XXI. DAIRY PRODUCTS.
65 Roese-Gottlieb Method.
The Roese-Gottlieb method for the determination of fat in plain ice
cream, a tentative method, was made official. (Second presentation
of the method for adoption as official.) The method is included in the
referee’s report for 1917 and has been published in the 1920 edition of
the methods?.
XXII. FATS AND OILS.
The Hiibl Method’ for the determination of the iodine absorption
number was dropped from the official methods. This method has not
been included in the 1920 edition of the methods. The Wijs method
for the determination of the iodine absorption number! was adopted
as a tentative method. This method has been inserted 17 and 18, in
the 1920 edition of the methods.
A recommendation “That all reports of iodine absorption number
should specify the method used” was adopted. This sentence has
accordingly been inserted in parenthesis following the heading “Iodine
Absorption Method” on page 244 of the 1920 edition of the methods.
XXIII. SPICES AND OTHER CONDIMENTS.
17 VOLATILE OIL IN MUSTARD SEED.
Adopted as an official method. (First presentation of the method for
adoption as official.) This method is printed in the 1920 edition of
the methods.
1C. A. 1910, 4: 218.
2 Assoc. Official Agr. Chemists, Methods, 1920, 236.
8 Tbid., 1916, 304,
4 Ibid., 1920, 245.
a Ee
1922] EDITING METHODS OF ANALYSIS 311
XXIV. CACAO PRODUCTS.
No changes or additions to these methods were made at the 1919
meeting.
XXV. COFFEES.
14 THE FENDLER-STUBER METHOD.—TENTATIVE.
Certain modifications of the Fendler-Stiiber method for the deter-
mination of caffeine were adopted, the modified method to remain as a
tentative method. The method, in its modified form, has been printed
in the proceedings'.
15 MODIFIED STAHLSCHMIDT METHOD.—TENTATIVE.
Page 271, line 5—The expression “‘75°C.” has been changed to “‘100°C.”’
This change provides that the final drying of the caffeine crystals
shall be at 100°C. instead of 75°C. The method as modified has not
been published.
XXVI. TEAS.
4 WATER EXTRACT.—TENTATIVE.
A modification of the former tentative method for the determination
of water extract in teas? was adopted as a tentative method. The
method has been published in the proceedings’.
14 CAFFEINE.
The modified Stahlschmidt method for the determination of caffeine
in teas was changed to provide that the final drying of the caffeine
crystals be made at 100°C. instead of 75°C. and the method as changed
was adopted as an official method. (First presentation of the method
for adoption as official.) This necessitates the change in the Chapter on
Coffees*.
XXVIII. BAKING POWDERS AND BAKING CHEMICALS.
The Wagner-Ross method for the determination of fluorids in baking
powders and baking powder ingredients was adopted as a tentative
method. The method is as follows:
REAGENTS.
(a) Anhydrous copper sulfate.
(b) Ground quartz or sand.—Purify by successive digestions with sulfuric acid and
aqua regia, wash with water and dry.
(C) 98.5% sulfuric acid—Prepare by boiling C. P. concentrated sulfuric acid in
an open vessel for about 20 minutes.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 533.
2 Assoc. Official Agr. Chemists, Methods, 1916, 335.
3 J. Assoc. Official Agr. Chemists, 1921, 4: 537.
4 Assoc. Official Agr. Chemists, Methods, 1920, 271.
312 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(d) 10% solution of silver sulfate in 98.5% sulfuric acid—Dissolve 10 grams of
silver sulfate, which has been ignited with an excess of sulfuric acid to drive off any
volatile acids present, in 100 cc. of the 98.5% sulfuric acid.
(€) Saturated solution of dry chromic acid in 98.5% sulfuric acid.
(f) Standard sodium hydroxide solution—Approximately 0.1N solution, preferably
standardized against chemically pure sodium fluosilicate.
(%) Standard hydrochloric acid solution—Approximately 0.1N solution carefully
standardized against the standard sodium hydroxide solution.
APPARATUS.
cr
Fic. 1. Apparatus FOR DETERMINATION OF FLUORIDS.
The apparatus required (Fig. 1) consists of a cylinder (A) of compressed carbon
dioxide or nitrogen, preferably the latter, fitted with a reducing valve (B), or other
safety device, for regulating the flow of gas; a drying train consisting of two wash
bottles (C) and (C), containing concentrated sulfuric acid for washing the gas used;
a 250 cc. generating flask (D), of pyrex glass, in which the sample is placed and which
is provided with two washing traps (EZ) and (£), both containing the 98.5% sulfuric
acid, the one next the generating flask being half full while the acid in the other is just
sufficient to make a seal; a Schmitz tube (F), containing the 10% solution of silver
nitrate in 98.5% sulfuric acid in the bulbed arm and glass beads (about 5 mm. in
diameter) in the other arm; two Bowen bulbs (G) and (G), each containing the saturated
solution of chromic acid in 98.5% sulfuric acid; a straight glass tube (H), 5 mm. in
diameter and 14 cm. in length, filled with glass wool; a second glass tube of the same
diameter and of sufficient length to extend to the bottom of the absorption tube (K),
which is a large test tube (25 cm. by 18 cm.) containing about 50 cc. of water and, for
materials relatively low in fluorine, an additional 10 cc. of the standard hydrochloric
acid solution to lessen the oxidation of any sulfur dioxide that may pass into the absorp-
tion solution. The apparatus is connected as shown in Fig. 1. On account of the
pressure that must be generated in the apparatus to produce a flow of gas against the
head of sulfuric acid great care must be taken in assembling to make all joints tight.
The ends of the glass tubing must be brought together and the rubber tubing, which
must be a good grade of heavy-walled gum tubing, covered with shellac. All glass
stop-cocks should be paraffined. A mantle of asbestos board, (M), should be placed
over the neck of the generating flask to prevent burning of the rubber connection at
the top of the flask. It is imperative that all parts of the apparatus be perfectly dry
before use, and that the solutions of concentrated sulfuric acid be protected against
absorption of moisture from the air.
1922! EDITING METHODS OF ANALYSIS 313
PRELIMINARY TREATMENT OF SAMPLE.
Remove all organic matter by burning. This is essential. It is carried out on the
weighed portion of the sample taken for analysis by making alkaline with sodium
carbonate and igniting in a muffle furnace at a temperature below redness (not to exceed
240°C.) to a white or nearly white ash. In the case of baking powder, add sufficient
water to complete the reaction between the acid and bicarbonate constitutents, evap-
orate to dryness on a steam bath and ignite to a white ash as directed above.
DETERMINATION.
Make a preliminary examination, using 10-20 grams of the sample to determine the
approximate quantity of fluorine present.
Mix the ignited residue (organic matter removed and thoroughly dried) of a weighed
sample containing 0.001—-0.1 gram of fluorine with 0.5 gram of the powdered silica and
5 grams of the anhydrous copper sulfate. Transfer the mixture into the generating
flask (A), (Fig. 1), the traps (Z) and (£) having been filled by suction with the requisite
quantity of 98.5% sulfuric acid without drawing any of the acid into the flask itself.
Connect the generating flask with the Schmitz tube. Then add 50 cc. of water to the
absorption tube (K), and, if the fluorine content of the sample is low also, add 10 cc.
of the standard hydrochloric acid solution. Connect the absorption tube with the
apparatus and then add 50-75 cc. of the 98.5% sulfuric acid to the generating flask
which contains the sample mixed with the powdered silica and copper sulfate and quickly
connect it with the source of carbon dioxide (or nitrogen). Adjust the flow of gas from
the cylinder so as to give a rate of about 2 or 3 bubbles per second and maintain this
rate throughout the determination. Shake the flask until the contents are well mixed
and then heat gradually to boiling. At this point in the determination a white scum,
indicating fluorine, will appear on the inside of the flask. Adjust the flame under the
flask so that the condensing sulfuric acid will wash this scum freely and completely
into the first trap, taking care to avoid heating so strongly that white fumes will be
evolved in noticeable quantity or the acid in the first trap made to boil. Continue the
boiling until the first trap is completely filled, about 30 minutes. Remove the flame,
taking particular care to regulate the flow of gas so that the relatively cool acid in the
traps does not flow back into the flask. Adjust the valve in the gas cylinder so as to
continue a uniform flow of gas at the rate of 2 or 3 bubbles per minute for 30 minutes
in order to wash all silicon fluoride into the absorption tube. Remove the latter, wash
its contents into a beaker, cover with a watch glass and boil gently 10-15 minutes to
expel dissolved gases. The operation of transferring the absorption solution should
consume as little time as possible as any prolonged exposure to air before boiling per-
mits the oxidation of any sulfur dioxide in solution. Cool the solution to room tem-
perature and titrate with the standard sodium hydroxide solution, using phenolphtha-
lein as indicator. Deduct the alkali equivalent of the standard acid added to the
absorption solution and calculate the fluorine present in the sample taken. The re-
action occurring is represented by the following equation:
H.SiF; +6 NaOH =6 NaF+2H20+H,Si0s.
After the solution has been titrated test for the presence of sulfates by the addition
of a little barium chloride solution. If the determination has been properly carried
out little or no sulfates should be present. If sulfates are present determine quanti-
tatively by precipitation with barium chloride! and correct the total standard sodium
hydroxide solution used in the original titration by the equivalent of sodium hydroxide
for the quantity of sulfuric acid present in the titrating solution.
1 Assoc. Official Agr. Chemists, Methods, 1920, 18.
314 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
XXVIII. DRUGS.
31 STRYCHNINE IN LIQUIDS.
The following addition was made to the tentative method for the
determination of strychnine in liquids:
Check the weight of the strychnine by dissolving the residue in neutral alcohol,
adding an excess of 0.1N sulfuric acid, and titrating back with 0.02N potassium hy-
droxide, using methy] red as the indicator. One cc. of 0.1N sulfuric acid is equivalent
to 0.0334 gram of strychnine and 0.0428 gram of strychnine sulfate. The U. S. P.
factor for strychnine to strychnine sulfate is 1.2815.
32 STRYCHNINE IN TABLETS.
The following addition was made to the tentative method for the
determination of strychnine in tablets:
Check the weight of the strychnine by dissolving the residue in neutral alcohol,
adding an excess of 0.1N sulfuric acid, and titrating back with 0.02N potassium hy-
droxide, using methyl] red as the indicator. One cc. of 0.1N sulfuric acid is equivalent
to 0.0334 gram of strychnine and 0.0428 gram of strychnine sulfate. The U. S. P.
factor for strychnine to strychnine sulfate is 1.2815.
XXIX. SOILS.
No changes or additions to these methods were made at the 1919
meeting.
XXX. REFERENCE TABLES.
No changes or additions to these tables were made at the 1919 meeting.
Respectfully submitted,
R. E. DoouittTLe, W. H. MacInrtire,
A. J. PATTEN, J. W. SALE,
B. B. Ross, G. W. Hoover.
Committee on Editing Methods of Analysis.
It was moved, seconded and adopted that the report be accepted,
the committee discharged and that the chair appoint a Committee on
Editing Methods of Analysis, consisting of six members, to serve for a
period of five years. The chair accordingly reappointed the same
committee to serve for a period of five years.
1922] BATES: QUARTZ PLATES STANDARDIZATION AND NORMAL WEIGHT 315
REPORT OF COMMITTEE ON QUARTZ PLATES STANDARD-
IZATION AND NORMAL WEIGHT.
By Freperick Bates (Bureau of Standards, Washington, D. C.),
Chairman.
Your committee, consisting of Frederick Bates, chairman, C. A.
Browne and F. W. Zerban, was appointed as a result of the 1919 report
of the referee on sugar! by the late A. Hugh Bryan. The subsequent
illness and death of Mr. Bryan made it practically impossible for the
committee to get any. satisfactory results on the matters involved in
time to present them at this meeting. It is therefore recommended
that the committee be continued for another year.
Adopted.
REPORT OF COMMITTEE ON METHODS OF SAMPLING
FERTILIZERS TO COOPERATE WITH A SIMILAR
COMMITTEE OF THE AMERICAN CHEMICAL
SOCIETY?.
The work of the committee was completed and reported last year?.
The committee has nothing further to recommend at this time except
a repetition of the 1919 recommendations, which are as follows, and
that the committee be discharged.
RECOMMENDATIONS.
It is recommended—
(1) That a sampler be used that removes a core from the bag from
top to bottom.
(2) That at least a pound of the material should constitute each
official sample sent to headquarters.
(3) That the entire sample submitted to the chemist be passed through
a 10-mesh sieve previous to its subdivision for analysis.
(4) That cores shall be taken from not less than 10 per cent of the
bags present, unless this necessitates cores from more than 20 bags,
in which case a core shall be taken from 1 bag from each additional
ton represented. If there are less than 100 bags, not less than 10 bags
shall be sampled, provided that in lots of less than 10 bags all bags
_ shall be sampled.
Respectfully submitted,
C. H. Jongs,
E. G. Prowutx,
B. F. Ropertson.
Committee on Methods of Sampling Fertilizers
to Cooperate with a Similar Committee of
Adopted. the American Chemical Society.
1 J. Assoc. Official Agr. Chemists, 1921, 4: 321.
2 Presented by C. H. Jones.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 594.
316 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
REPORT OF COMMITTEE ON THE REVISION OF METHODS
OF SOIL ANALYSIS!
By C. B. Lipman (Agricultural Experiment Station, Berkeley, Calif.),
Chairman.
The gigantic strides which have been taken by chemists in recent
years in their progress on soil studies and the relation of soils to plants,
have rendered necessary very material revision, not only of the actual
methods of analysis which have been in vogue in the past, but also of
the point of view and conceptions of the soil chemist with reference to
the value and the validity of the procedure of soil analysis itself. This
committee has, therefore, tried to bear in mind these important advances,
and to revise the methods of soil analysis as much as possible in accord-
ance therewith. It must be obvious to all chemists, and particularly
to all soil chemists, that the difficulties in the path of making a perfect
revision are very numerous and, in some cases, almost insuperable. Your
committee has, however, done the best that it could in the light of the
knowledge at hand.
Three years have passed since the committee had an opportunity to
give detailed consideration to this report and to the methods of soil
analysis. Much, indeed very much, has transpired since, which will
make it necessary to suggest to the association many further far-reaching
revisions and additions. It is hoped, therefore, that the committee will
be continued and that it will be requested to present to the next meet-
ing of the association a new statement of the revised methods of soil
analysis.
Adopted.
It was moved, seconded and adopted that the committee be con-
tinued and that someone be appointed to fill the vacancy caused by
the resignation of E. C. Shorey.
1 Presented by W. H. MaclIntire.
1922] HASKINS: PHOSPHORIC ACID IN BASIC SLAG 317
REPORT OF COMMITTEE ON VEGETATION TESTS ON THE
AVAILABILITY OF PHOSPHORIC ACID IN BASIC SLAG.
By H. D. Hasxis (Agricultural Experiment Station, Amherst, Mass.),
Chairman.
Your committee regrets its inability to make a final report on the
results of cooperative field and pot experiments with basic slag phos-
phate. In apologizing for this apparent lethargy, the present chairman
would point out the great difficulty in obtaining reliable data in a short
time on the activity of different phosphates through the medium of
field experiments. On fields which are not noticeably deficient in phos-
phorus compounds, several years of preliminary experiments are neces-
sary in fitting the soil for a final test. In other words, a soil must be
exhausted in active phosphoric acid compounds, as well as abundantly
supplied with all other necessary plant food constituents, before it can
furnish reliable data as to the phosphoric acid availability of the differ-
ent phosphates employed in the experiment. The same is true, of
course, in pot experiments, although many times a limited amount of
soil exhausted in phosphoric acid may be secured from some local experi-
mental field. Then, too, during the past several years many agri-
cultural experiment station workers have been engaged in the business
of war, and it has been impossible to carry on many activities outside
of the regular routine of station work.
It is apparent from a somewhat hasty examination of the data at
hand that final reports have been received from the several experi-
menters who undertook this cooperative work. Nine pot and five field
experiments have been conducted in various parts of the country and
your committee is of the opinion that from some of the pot work at
least very definite and positive results will be secured as to the activity
of the phosphoric acid in basic slag phosphates. In conclusion, your
committee asks an extension of time for another year in order to formu-
late a final report.
Adopted.
It was moved, seconded and adopted that the committee be con-
tinued.
-
The meeting adjourned at 1 p. m. to reconvene at 2 p. m.
THIRD DAY
WEDNESDAY—AFTERNOON SESSION.
REPORT OF SECRETARY-TREASURER FOR
By C. L. Atspere* (Bureau of Chemistry,
RECEIPTS.
1919
Nov; 15))Bankbalance’ ooc.0c, <2. ceaioasa rat arele e averes ale aye solar euavere te scsieliepetersve fon aeeetee $550.71
Dues from 2 institutions (Alabama Polytechnic Institute and San
Francisco Department of Public Health) received too late to in-
clude in-report for L919 eS x. chess evs cos cts peters tie 2 rope ea 2) trees ene
Dues for the year 1920 from 52 Federal, State, Municipal and Can-
adian ‘Orpanizationss:~ cr). or. .kfarebotacictds os asthe Delete eee ae
Reimbursement checks drawn on Secretary-Treasurer account for
This Journals. 287 Re AAR then be oe EEE Sat ee ee ee eee
Check No. 75 (Feb. 21, 1917) on which payment was stopped...... 0.16
10.00
258.00
1920
July 18 Transferred from Metropolitan National Bank to Commercial
National ‘Bank. .s .fig-sraeu exes oats anes Solera oe one a eee
$1784.60
* Present address, Food Research Institute, Stanford University, Calif. ee
+Two dollars transferred from Journal account to complete payment for one institution.
318
al
1922| - ALSBERG: REPORT OF SECRETARY-TREASURER 319
THE YEAR ENDING NOVEMBER 17, 1920.
Washington, D. C.), Secretary-Treasurer.
DISBURSEMENTS. Check
1919 : Amt No.
Noy. 20 J.S. Hodges, perforating 500 cooperative circulars......... $ 080 123
Noy. 20 Tips, New Willard Hotel, for 1919 meeting................ 30.50 124
Noy. 20- Car fare, phone calls, 1919 meeting......................- 2.20 125
RN Cree LOE SEAR E soy an crn cere ect ae a eo Ne Se iat vee os 15.00 126
Noy. 25 Chas. 5G. Stott & Co., 1500 window envy elopesii tnd 8.28 127
Noy. 25 5000 special request envelopes (2 cent)....................
5000 special request envelopes (1 cent).................... 185.40 128
Noy. 28 Ware Bros. Company, two 14-page ads in the American Ferti-
TELE coe! pnt deseo OS AICP: OUST CHO DMEE RCE ae 50.00 129
Dec. 2 American Chemical Society, 14-page ad in December, 1919
ASSET UU TLE PE TN OEMI ee er ne s eee lo eeelas 19.25 130
Dec. 2 Byron S. Adams, printing 1500 window envelopes.......... 3.75 131
Pecans ate OSLADE ere settee Ste ee ns eh eee ee linea een atene.s 15.00 132
an American Chemical Society, 14-page ad in J. Am. Chem. Soc.. 9.16 133
19
Tam. . 2: AMsS EN AIS Oe esieta stabi eee ree 50.00 134
Jan. 2 Post Office box rent for quarter ending March 31, 1920...... 2.00 135
Jan. 6 Chas. G. Stott & Co., printing 2000 letterheads, alphabetical
AER A ee ee ee ae ee ee lee eee ies 13.50 136
Jan. 10 The Science Press, 14-page ad in November 7 and 14, 1920
RESUS Eye Le ee ee tie tc araele, oars uote ole 10.80 137
Jan. 10 American Chemical Society, 14-page ad in January, 1920
ABSUC Ole) ITO PGs OEM tee es nie cio eae ies 19.25 138
Jan. 20 Hay Rubber Stamp Company, cushion stamp............. 1.15 139
Jan. 17 American Chemical Society, 144-page ad in January 1920
ASSUC ted oe ATE CELTS OE nore nay ahaha a ha sroun sicistoss sci tloisiees 9.16 140
Mar. 24 Post Office box rent for quarter ending June 30, 1920...... 2.00 141
Wbrirsesed MLOStape ys Sas. Aaa ai ee ee tte ieran race Sere. oa isin ale 50.00 142
Apr. 9 Chas. G. Stott & Co., printing 500 letterheads............. 29.22 143
Apr. 17 Williams & Wilkins Co., ad in J. Biol. Chem................ 8.00 144
Miva has G: Stott @ Go paper... 2 soc ee anes fe a ccree ee 4.95 145
May 21 A. Zichtl & Co., binding Methods and Vols. I and II This
ADT eet CERO ED GUG Da RRs SHOR OS OE OO DCA SER AEee 7.25 146
June’22) G.I. Alsberg; transfer of account:.................-0:2--.- 203.25 147
July 14 Post Office box rent for quarter ending September 30, 1920. . 2:00 1
July 14 Postage, 3000 one-cent stamps, 1500 two-cent stamps, 100
three-cent stamps, 50 special delivery stamps. *.......... 68.00 2
Noy. 2 Byron S. Adams, printing 1000 programs, 1920 meeting. . 39.25 3
UD. TH LEG SE asco SO Bt 6 Be GUC GEELOI DE GePIO RI GE Ho ae 4.00 148
avast gebarnksbalance am: ety vents Sne helieenen ss vsie sindec- 921.48
$1784.60
The undersigned committee has examined the books of the Secretary-
Treasurer and finds them correct.
Respectfully submitted,
ANpDREW J. PATTEN,
H. H. Hanson.
Adopted. Auditing Committee.
320 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
FINANCIAL REPORT ON THE JOURNAL
By C. L. Atsperc* (Bureau of Chemistry,
RECEIPTS.
1915
Nov.) “i. ‘Bank balancer: ce se eitracteiancis oo ole < blo eee ot ets cee aie $ 569.48
Dec: SL dnterest sys svc erses cei o Monson eectae attocke esi eleinereiee etre eietes 2.92
@heeks ‘and icash received << esos ccisieraieiessasereleraniole eves a eke 7,638.28
Less exchange on foreign noteS.............0eeeseeeeees 19.01
7,619.27
Transfer of account from the National Metropolitan Bank to the
‘(American ‘National (Bank: )7., 5s... c:eieiusie eatin cic siete cle eae 1,289.68
$9,481.35
*Present address, Food Research Institute, Stanford University, Calif.
1922]
ALSBERG: REPORT OF THE JOURNAL
AND BOOK OF METHODS.
Washington, D. C.), Chairman, Board of Editors.
DISBURSEMENTS.
H. A. Freeman, refund for excess payment on subscription .$
N. A. Parkinson, reimbursement 2 trips to Baltimore.......
Williams & Wilkins Company, Baltimore, Md..............
Williams & Wilkins Company, Baltimore, Md., Subscription
of Eastman Kodak Company for which M. O. was deposited
Chas. G. Stott & Co., printing 500 letterheads.............
Telegram to E. B. Passano, Baltimore yIMd 5 nccrstieielvrsiscscrsic
IPGSCA QE Re aries erctete aire, Sis Teieeserehtera tele clovacsincte elements tents
1 Racial (see ce tog ae bo GEAOIO ECO) DODO Cm nce Uc arIMO CMOS
GED Alsberg> telegram sic. stsisis,<fc ste isiss fs oterstereiaia a stsielonc 5°
Cam yAlsbers> telegram. icc). cos sa)-tc)aererelslcrerare ere fere cio tore
SIEVE Merson) POStAawe incisive ste sheesh vel eae eatel eveiee) Seo «
EN CRB IANCKHPOStAC OE atta atsl cavers caters ws cater Sderanecoysy eile eich
Williams & Wilkins Company, subscription of Institute fiir
FARO Iie Goad Oboe o OPO OU Teno CORDMOT One eriaace
ETA GRBs pera tere rote ay 8 ean ear oey cota le vatonsievolovsatotiavs itera’ stavondlecatentects
Payment for Volume I, No. 1, sold Azor Thurston..........
Industrial Printing Co. on account printing Volume III,
INO Sem Parent Pageveney Stoke eects tran ys a1syose/oh oe atenelietey saepe\ey sasieici skeusi si0)s
eda Printing Co., on account printing Volume III,
Ob don Sho cne non son ononeeae nos Oo Ae. SOmonmnDO ro orn
V.S. Bentley, refund on subscription.....................
Raymond Wells, refund on subscription...................
Industrial Printing Co., on account Volume III, No. 2......
Expenses N. A. Parkinson, 2 trips to Baltimore............
The Duplicating Office, 500 copies of instructions to referees. .
GaLvAlsberetransfer ofjaccount +). seni settee oe cictsiele
Industrial Printing Co., to complete payment on Volume III,
N. A. Parkinson, expenses trip to Baltimore...............
Postmaster, 10,000 two-cent window envelopes ...........
The Duplicating Office, 5000 letterheads, 3000 circular letters.
G. E. Stechert & Co., commission on subscriptions.........
Joe Cohen, affidavits for J. A. MacLaughlin...............
C. A. Stott, printing and furnishing 10,000 letterheads......
The Postmaster, mailing May 15, 1920 number............
Janet K. Smith, 200 two-cent, 200 one-cent stamps.........
American Chemical Society, 14-page ad in J. Ind.»Eng. Chem.
Macon Dray & Co., refund for excess payment on subscription
A. J. Holden, refund on journals which could not be furnished
and $1 refund for excess payment on methods...........
Janet K. Smith, 1000 one-cent stamps....................
Proctor & Gamble Co., refund for excess payment on sub-
ele Nats Gao heyito tm c 0 URED OR ORD an CO ae ee nner ae ae
J. H. Gill, refund for excess payment on subscription. .....
Jose L. Suarey, refund for excess payment on Book of
GTI GG Fy, oe ees canes ASS Gein ia el ee ae eer
A. Helsall, refund for excess payment on Book of Methods. .
Industrial Prmting Gon Gn, Accounty.aes. oe coal aio oes
Peter McVeigh, refund ‘for excess payment on Book of
VWlethodsseyeer ter eerie sa ret teats Maniacs satanenine
Industrial Printing Co., miscellaneous items...............
Industrial Printing Co., OMACCOUNL Aare a ecoce nae sie
Amt.
1.00
7.10
1,289.68
313.25
5.65
243.80
45.15
3.20
2.00
43.75
25.00
6.00
105.98
1.20
21.00
10.00
1.43
1.00
-50
-50
500.00
. 50
87.78
500.00
321
25
RPOONORW tO ee
ie
322 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Sept. 18 Industrial Printing Co., on account...................++-- 500.00 24
Sept. 18 A. Zichtl & Co., binding Volume III, This Journal........ 2.75 25
Sept. 20 ae Postmaster, box rent for quarter ending December 31,
Rrra roto nA ahoar ds acc docs abiohocsntet 2.00 26
Sept. 22 A. ‘Poole Wilson, payment for copy of Volume III, No. 1 re-
CUTIE 52 0 c5 Pt 5 sesame step Gye operates (evssc aio seeeiererete ies 1.40 27
Oct: (2 (JoeiCohennotanialiservicesmen ere eee eee eee 1.25 28
Oct. 2 S.R. Curzon, refund for excess payment on Book of Methods. 1.16 29
Oct.. 4° TndustrialiPrmtinpiCos oniaccounts) 5.0.) -..2 eee eee neee 500.00 30
Oct. 5 Industrial Printing Co., printing 2690 wrappers, 3000 labels. . 40.75 31
Oct. 5 P.J.Saxer, refund for excess payment on Book of Methods. . -50 32
Oct. 5 Henry Larouche, refund for excess payment on Book of
Methods i 5.2i estan Ser atertrete a ai ee clots hae Rae eels ete 50 33
Oct. 12°" “Rostage tras as ce Manic tan. ctctete Mie ena eel ns detested keene 20.00 34
Oct. 19 W. G. Gaessler, for Volume I, No. 1, Volume II, No. 1, Part I 2.50 35
Oct. 25° Industrial) Printing Co:oniaccount..c-.). 221s. .1)-nle cient 500.00 36
Nov. 1 - Joe'Cohen; motarial. services. ceia-+- cele eels 2 2 es Or ime -50 37
INoy;, °8) sindustrial Printing Co:, on accounts... 1. so0e4 ese see ee 500.00 38
INO V2, SSM Cash eid ak aa yat nae Gr sishae arsioeack otvaevamtarelers otra eee ee 13 26
Noy. 12 C. L. Alsberg, reimbursement Secretary-Treasurer account
for checks drawn) for Jourmal\..), .5..% see eee eee oe 762.48 40
Noy. 12. N. A. Parkinson, reimbursement freight charges on methods. . 15 41
Nov; (Gi ‘Bank balancey iets. sacimiociacra seta elicit ane $2,586.79
Plus deposit of November 8....................- 570.94
$3,157.73
bessroutstandingychecksSimcmchn stein aMee 1,267.29
— 1,890.44
$9,481.35
The undersigned committee has examined the above report and finds
it correct.
Respectfully submitted,
A. J. Parren,
H. H. Hanson.
Auditing Committee.
Adopted.
REPORT OF THE BOARD OF EDITORS.
By C. L. Auspere! (Bureau of Chemistry, Washington, D. C. )s
Chairman.
The circulation of the last number of The Journal that was issued,
that is Volume III, Number 4, was 720 copies. Including the additional
subscriptions received up to a few days ago, the circulation will be about
850 for the first number of Volume IV. Of course, at the present time
it is impossible to say how many renewals there will be. In the past
over two-thirds of the subscriptions have been renewed. The reason
it is not possible at this time to make a definite statement of the total
circulation of Volume IIT is that the majority of the subscriptions do
! Present address, Food Research Institute, Stanford University, Calif.
1922] ALSBERG: REPORT OF THE BOARD OF EDITORS 323
not begin with the first number of the volume but are scattered all
through the volume. It is estimated that at the present rate of re-
ceiving new subscribers the subscription list should be at least 850 or
900 within the next few months but, of course, no definite estimate
can be given. No serious effort has been made since last March by the
management of The Journal to increase the subscription list because the
work on the methods took up all the available time of those who other-
wise would have been engaged on The Journal. Without any effort
whatever to increase the circulation of The Journal, in the neighborhood
of ten or a dozen new subscriptions a month have been received. Since
the first of October some circularizing has been done, the work on the
methods having been disposed of, and in the neighborhood of fifty
subscriptions a month have been received. How long that will con-
tinue it is impossible to say. Should this rate of increase continue during
the year, the circulation of The Journal would reach 1200, which would,
in all probability, carry the cost of printing. -At the present time, with
a subscription list between seven and eight hundred, The Journal has
a deficit.
It is also impossible to calculate from the receipts for The Journal
this year exactly what the deficit is on each volume. The reason for
this is that it has not been possible as yet to adjust our dispute with
the former printers. Unfortunately, it was impossible to secure from
the printer the list of original subscribers and it became necessary to
build up a new list and begin all over again. In spite of this handicap,
the list of subscribers is now within a couple of hundred of what it was
when the publication of The Journal was suspended in May, 1917.
The income, however, has not been proportionate because, of course,
the association was under obligation to furnish the remainder of Volume
III to such old subscribers as could be reached who had subscribed for
it but had not received it, the money being tied up in the hands of the
former printer who, under the contract, handled the business affairs of
The Journal. To sum up, the total receipts for The Journal have been:
In the form of subscriptions, $1733.17; in the form of advertising, $270;
making a total of approximately $2000. The cost of printing The
Journal has been such that this leaves a deficit of about $3200 on Volume
III. It is not possible at the present time to estimate exactly what
the prospects of income for Volume IV will be. There is on hand at
present from subscriptions and advertising for Volume IV $2600, which,
of course, will not meet the cost of production. If it is assumed that
there is to be no material increase in the cost, and the number of sub-
scriptions is placed somewhere in the neighborhood of 750, which cor-
responds to about the present circulation, and if it is assumed that
there will be no reduction in the cost of printing, both of which esti-
mates are ultraconservative since there has been a drop in the cost of
324 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
paper and printing and from thirty to fifty subscriptions a month are
being received at the present time, then there is a possibility of a deficit
slightly in excess of $3000 for Volume IV of The Journal. If, however,
the cost of printing goes down somewhat, and if subscriptions continue
to come in at the present rate, the deficit will be very much less. That
may look like a serious situation, but in reality it is not.
It is impossible to submit a complete financial statement on the Book
of Methods for the reason that the bills for printing and distribution
have not been received. Only an estimate has been received as to the
probable cost of producing the book and this estimate is in the neighbor-
hood of $4000 and $4500. It can not be estimated exactly until all
the bills are received. Up to the tenth of November, 1710 subscriptions
to the Book of Methods had been received. On that basis, if every-
body pays his bill, the money in sight for the Book of Methods, if not
another copy were sold, is $8875.45, which should leave a surplus on
the Book of Methods of something in the neighborhood of $4000. It may
be as low as $3000; it may be as high as $4500. It is not possible at
this time to estimate it. If not another copy were sold and only the
money received in payment for the copies of the Book of Methods that
have now been sold were received, the deficit on The Journal would be
more than wiped out. This $8800 on the Book of Methods is not all
that will be received because, although no circularizing to solicit sub-
scriptions to the Book of Methods has been done, since the first of
September an average of 39 subscriptions per week has been received
for the Book of Methods. There is every prospect that from 25 to 50
a week will come along for several months at least, and perhaps for a
year. The deficit on The Journal is due to the fact that a new sub-
cription list had to be built up and the cost of printing has practically
doubled since 1915. In connection with the building up of the sub-
scription list, advertisements were inserted in the leading chemical
journals announcing the resumption of publication of The Journal, and
asking those who were subscribers and had paid for something that
they had not received, to notify the association. It is unquestionably
a fact that those advertisements were overlooked by a good many
people, but they were the only means of reaching the former list of
subscribers. There are several gentlemen in attendance at this meeting
who did not see them, and who have asked about their old subscriptions.
Any one who may have been a subscriber in the past and who has not
received all his copies, is urged to notify the editorial office of that fact.
In that event he is entitled to receive the remainder of the copies for
which he has paid, and if any one knows of any of his colleagues of whom
the same is true, please ask them to communicate with the editor’s
office. In short, the situation is this: The Journal at the present time
probably is running a deficit of something around $1500, possibly $2000
1922] ALSBERG: REPORT OF THE BOARD OF EDITORS 325
a year. Ifseveral hundred former subscribers can be reached and renew
their subscriptions, and the subscriptions are coming in at a rate which
makes that probable, the deficit will be correspondingly less. About
1200 subscribers must be secured to break even. In other words, about
400 more subscriptions are needed. The methods are showing a profit
which, at the present time, wipes out the deficit on The Journal. How
long this will continue will depend, in the first place, upon how the
subscription list to The Journal increases, and, in the second place,
upon how continuous the demand remains for the Book of Methods.
Up to the present time exactly $7619.27 has been received for The
Journal and for the Book of Methods, and there is $1890.44 in bank.
That does not mean anything because it is impossible to estimate exactly
what the cost of printing the Book of Methods will be because the
bills are still outstanding. Part of the cost of producing the methods
has been paid, but not all.
Number 1 of Volume IV is ready to go into the mail; Number 2 of
Volume IV will follow within a month, and it is hoped that by spring
the proceedings will be caught up completely. There is not any doubt
that this will favorably affect the subscription list to The Journal because
there are a certain number of subscribers who are interested only in the
current proceedings and are not subscribing as long as back proceedings
are being published. By spring it is hoped that The Journal will be
in a position to print not merely proceedings, but such original com-
munications coming into the field of work of this association as the
Board of Editors may deem wise to furnish a place in The Journal.
It was moved, seconded and adopted that the report be received,
that the thanks of the association be tendered to the Editor in Chief,
and his able assistant, Miss N. A. Parkinson, and to the Board of Editors
for the excellent and efficient service they rendered in connection with
the publication of The Journal and the Book of Methods.
Considerable discussion followed the presentation of the Report of
the Board of Editors. The question of publishing separates containing
individual chapters from the Book of Methods was taken up in detail
and a motion made that the Board of Editors.be empowered to print
the chapter on fertilizers as cheaply as possible for sale to students.
Substitute motions were made later empowering the Board of Editors
to print a students’ edition of the entire Book of Methods or such part
thereof as they deemed wise, on cheaper paper than the regular edition,
which could be sold at a very much lower price. These motions were
withdrawn, however, and a motion was made, seconded and carried
that this matter be held over for one year at least.
326 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
REPORT OF COMMITTEE ON RECOMMENDATIONS
OF REFEREES.
By B. B. Ross (Alabama Polytechnic Institute, Auburn, Ala.), Chairman.
Your committee has no formal report to present other than that
embodied in the several reports submitted by the chairmen of Sub-
committees A, B and C, but deems it advisable to offer some suggestions
relative to the desirabilty of securing earlier reports from the referees
and associate referees. In this connection, the committee realizes that
many of the collaborators must report more promptly to the referees,
if a speeding up of the reports of the referees is to be attained. It is
also desirable, if possible, to secure for the consideration of the several
subcommittees, complete reports from the referees, or such abstracts as
will set forth definitely the reasons upon which the recommendations of
the referees are based. Many of the referees supply advance copies of
their full reports, but others, owing possibly to delay in receipt of reports
from collaborating chemists, or to the pressure of routine work, send in
abstracts of their reports and, in some cases, these abstracts fail to give
in sufficient detail the reasons for suggested changes or modifications in
the methods. In some instances reports of collaborative work are not
submitted.
The committee desires the referees and associate referees to supply
each member of the appropriate subcommittee with copies of their
reports and recommendations sufficiently well in advance of the meet-
ing to permit the individual members of the committee to study and
consider the report thoroughly prior to the date of the meeting of the
association. In this way, the members of the various subcommittees
will have an opportunity to become well posted on the several subjects
to be considered by their committee and each committee will thus be
better prepared to act promptly and intelligently upon reaching the
meeting.
The committee realizes the difficulties which have confronted referees
and collaborating chemists during the period of transition from a war-
time status to normal working conditions, and hence does not make
the above suggestions in a spirit of fault finding. It is hoped, however,
that all members will appreciate the importance of pursuing the course
outlined.
Adopted.
1922] ROSS: SUBCOMMITTEE A ON RECOMMENDATIONS OF REFEREES 327
REPORT OF SUBCOMMITTEE A ON RECOMMENDATIONS
OF REFEREES.
By B. B. Ross (Alabama Polytechnic Institute, Auburn, Ala.), Chairman.
[Fertilizers (borax in fertilizers, preparation of ammonium citrate, precipitated phos-
phates, nitrogen, potash), potash availability, inorganic plant constitutents
(sulfur and phosphorus in the seeds of plants, calcium and magnesium
in the ash of seed), water, tanning materials and leather,
insecticides and fungicides, and soils (sulfur
‘ in soils).]
FERTILIZERS.
BORAX IN FERTILIZERS.
It is recommended—
(1) That the Ross-Deemer method for the determination of borax
in fertilizer materials and mixed fertilizers, which reads as follows, be
adopted as a tentative method:
ROSS-DEEMER METHOD FOR THE DETERMINATION OF BORIC ACID.
REAGENTS.
(a) Barium chloride solution —(10%).
(b) Barium hydroride—Powdered.
(c) Standard boric acid solution —(0.1N).
(d) Standard sodium hydroxide solution.—Prepare this solution free from carbonates
by first making a saturated solution in order that any sodium carbonate present will
be precipitated when the solution is allowed to stand in a vessel from which the carbon
dioxide of the air is excluded. Filter through a hard filter that has been soaked in
alcohol; dilute a portion to about 0.1N and accurately determine the strength of the
solution by titration, as described under the determination of mineral salts, against
the standard boric acid.
(e) Hydrochloric acid solution —(1) About 0.1N and (2) about 0.5N.
(f) Neutral mannite (mannitol).
(&) Methyl red solution —Dissolve 0.1 gram of methyl red in 100 cc. of a hot 50%
solution of alcohol and water, and filter.
(hh) Phenolphthalein solution—Dissolve 1 gram of phenolphthalein in 100 cc. of
alcohol.
DETERMINATION.
(a) Mineral salts—Dissolve 5-10 grams of the sample in 50-75 cc. of hot water,
decompose carbonates, if present, with a slight excess of hydrochloric acid; heat to
boiling and add sufficient barium chloride to precipitate the sulfates, using about 10 cc.
in excess; next add in small amounts sufficient powdered barium hydroxide to make
the solution alkaline, avoiding a large excess; boil for about 5 minutes, or until any
ammonia present has been expelled; filter and wash into a 300 cc. flask, make acid
with hydrochloric acid, using an excess equivalent to a few cc. of 0.1N solution; boil for
15 minutes to expel carbon dioxide, cool by placing the flask in cold water and bring to
neutrality by first adding 4-5 drops of methyl red and then standard sodium hydroxide
solution until the color of the solution changes from pink to yellow. If the neutral
point has been exceeded, or if there is any doubt as to this, restore the pink color by
adding a few drops of approximately 0.1N hydrochloric acid and change the color to
yellow again with the minimum amount of the standard sodium hydroxide solution.
328 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Add 1-2 grams of neutral mannite and a few tenths of a cc. of phenolphthalein solution,
note the buret reading, and again titrate the solution with the standard sodium hydroxide
solution until a pink color develops. Add a little more mannite and if the pink color
disappears continue the addition of the standard alkali until a pink color again appears.
Repeat until the addition of mannite has no further action on the end point. If the
content of boric acid in the solution titrated is low, one addition of mannite is usually
sufficient. From the volume of the standard alkali required in the titration after the
addition of the mannite, corrected for the volume required when running a blank,
calculate the quantity of borax in the sample, 1 cc. of a 0.1N sodium hydroxide solution
being equivalent to 0.0062 gram of boric acid, or to 0.00505 gram of anhydrous borax.
When an acid solution of the sample to be analyzed gives no precipitate upon the
addition of a solution of calcium chloride and sufficient ammonia to give an alkaline
reaction, phosphates and iron and aluminium salts are absent and that portion of the
determination which involves treatment with barium chloride and barium hydroxide
for the removal of these constitutents may then be omitted.
(b) Mized fertilizers and organic compounds.—Weigh 5 grams of the sample into a
250 cc. beaker, add 50cc. of hot water, cover with a watch glass, digest for 15-20 min-
utes on the water bath, filter and wash into another beaker of the same capacity. Heat
the filtrate to boiling and add 15 cc. of barium chloride solution followed without undue
loss of time by suflicient powdered barium hydroxide to give an alkaline reaction as
indicated by phenolphthalein, boil for about 5 minutes, gently to prevent frothing over,
filter and wash. Or, if preferred, make up to the mark in a graduated flask and take
an aliquot portion. Evaporate the filtrate or aliquot portion to dryness in a platinum
or porcelain dish and ignite the residue, preferably in a muffle furnace, at a tempera-
ture just below redness until organic matter is completely carbonized. Treat the
ignited residue with hot water, make slightly acid with hydrochloric acid, heat nearly
to boiling, make alkaline again with a slight excess of barium hydroxide and filter into
a 300 cc. flask. Acidify with hydrochloric acid, using an excess equivalent to a few
ce. of a 0.1N solution, boil to expel carbon dioxide and titrate as directed under the
determination of mineral salts.
If the barium hydroxide has been added only in slight excess there is a tendency for
the filtrate to become acid during evaporation with a possible loss of borax. It is
therefore important that the solution be kept alkaline by repeated additions of barium
hydroxide, if necessary, until the evaporation has been completed
If the filtrate from the barium chloride-barium hydroxide precipitate is titrated in
this determination without first destroying soluble organic matter, the end points in
the titration will usually be too indefinite to give accurate results. The purpose in
evaporating the filtrate and igniting the residue is therefore to get rid of soluble organic
constituents which interfere with the titration. When the sample contains a relatively
high boric acid content, in excess of 0.5 per cent, a smaller sample may be taken and
the quantity of organic matter present may then be too small to seriously interfere
with the sharpness of the end points during the titration. When such is the case,
boil the solution after the addition of the barium hydroxide until any ammonia present
has been expelled, omit evaporating the filtrate from the barium chloride-barium
hydroxide precipitate; add to the filtrate an excess of hydrochloric acid equivalent to
a few ce. of a 0.1N solution, boil to expel carbon dioxide and titrate as directed under
the determination of mineral salts.
Approved.
(2) That further work be done on the comparison of the proposed
tentative method with the distillation method of Bartlett.
Approved.
1922] ROSS: SUBCOMMITTEE A ON RECOMMENDATIONS OF REFEREES 329
(3) That results of determinations by these methods be reported
hereafter in terms of boric acid, together with the equivalent of an-
hydrous borax.
Approved.
PREPARATION OF AMMONIUM CITRATE SOLUTION.
It is recommended—
_(1) That the proposed method be given further study, with collabora-
tion, with a view to adoption in 1921.
Approved.
PRECIPITATED PHOSPHATES.
It is recommended—
(1) That the proposed method be further studied, with collaboration,
during the ensuing year.
Approved.
NITROGEN.
It is recommended—
(1) That the study of the du Pont nitrometer be abandoned.
Approved.
(2) That the associate referee for 1921 be directed to study the
DeVarda alloy method! as applied to the determination of nitric and
nitrous acids in fertilizers.
Approved.
POTASH.
No report or recommendations.
POTASH AVAILABILITY.
No recommendations.
INORGANIC PLANT CONSTITUENTS.
SULFUR AND PHOSPHORUS IN THE SEEDS OF PLANTS.
It is recommended—
(1) That the associate referee consider the suggestion for further
work on total sulfur and total phosphorus. ‘
Approved.
(2) That the associate referee consider the construction of a bomb
similar to but larger than that recommended by Parr for the determina-
tion of sulfur in coal.
Approved.
(3) That the associate referee consider the use of sodium peroxide as
an oxidizing agent with a small amount of potassium chlorate as an
accelerator.
Approved.
1 Chem. Zlg., 1892, 16: 1952; J. Ind. Eng. Chem., 1919, 11: 306; 1920, 12: 352.
330 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(4) That the associate referee consider the suggestion that care be
exercised to insure the complete oxidation of sulfur and phosphorus
before it is neutralized with acid.
Approved.
(5) That the referee consider carrying on this work with a view to
making the sulfur and phosphorus determinations on the same charge.
Approved.
CALCIUM AND MAGNESIUM IN THE ASH OF SEED.
It is recommended—
(1) That further work be done on calcium and magnesium in such
material as the ash of seed, as recommended in 1919.
Approved.
(2) That some cooperative work be done on the colorimetric method
for manganese.
Approved.
(3) That a method be devised for the determination of iron and
aluminium in the filtrate from magnesium, as recommended in 1919.
Approved.
WATER.
It is recommended—
(1) That work on bromine be continued during the ensuing year.
Approved.
(2) With regard to the recommendation of the referee as to the
insertion in the methods of analysis of the statement given below relative
to the method for bromine in the presence of chlorine and iodine, the
committee recommends that this statement be published in the pro-
ceedings of the association for the information of any chemists having
occasion to make such determinations, pending the final adoption of a
method.
A volumetric method for the determination of bromine in the presence of chlorine
and iodine has been published?. Cooperative work indicates that this is probably the
best method for bromine which has been published, but the results obtained show that
only about 95 per cent of the bromine present is recovered, when 80 mg. of bromine
are contained in the portion of the sample used for analysis. The method is satisfac-
tory in the absence of iodine as shown by the cooperative work on water in 1919.
Approved.
TANNING MATERIALS AND LEATHER.
No recommendations.
INSECTICIDES AND FUNGICIDES.
It is reeommended—
(1) That the hot bromate method for the titration of the acid dis-
1J. Ind. Eng. Chem., 1920, 12: 358.
1922] ROSS: SUBCOMMITTEE A ON RECOMMENDATIONS OF REFEREES 331
tillate in the official distillation method for the determination of total
arsenic! be adopted as an official method. (First reading.)
Approved.
(2) That the bromate method for the determination of arsenious
oxide in Paris green! be adopted as an official method. (First reading.)
Approved.
(8) That the bromate method for the determination of arsenious
oxide in calcium arsenate? be adopted as an official method. (First
reading.)
Approved.
(4) That the official distillation method? as applied to the determina-
tion of total arsenic in London purple be adopted as an official method.
(First reading.)
Approved.
(5) That the zinc oxide sodium carbonate method? for the determina-
tion of total arsenic in London purple be adopted as an official method.
(First reading.)
Approved.
(6) That the bromate method for the determination of arsenious
oxide in zinc arsenite* be adopted as an official method. (First reading.)
Approved.
(7) That the official method for the determination of water-soluble
arsenic in lead arsenate® be adopted as an official method for the deter-
mination of water-soluble arsenic in zine arsenite.
Approved.
(8) That the tentative method for the determination of arsenious
oxide in lead arsenate® be adopted as a tentative method for the deter-
mination of arsenious oxide in calcium arsenate.
Approved.
(9) That the method for calcium oxide’? be amended by eliminating
the words, “‘or ignite and weigh as oxide’, and when so amended that it
be adopted as a tentative method.
Approved.
(10) That the modified method for calcium oxide*® be adopted as a
tentative method. -
Approved.
(11) That in the “General procedure for the analysis of a product
containing arsenic, antimony, lead, copper, zinc, iron, calcium, mag-
1 J. Assoc. Official Agr. Chemists, 1921, 5: 34.
2 [bid., 36.
2 Assoc. Official Agr. Chemists, Methods, 1920, 54.
4 J. Assoc. Official Agr. Chemists, 1921, 4: 397.
5 [bid., 5: 47.
* Assoc. Official Agr. Chemists, Methods, 1920, 59.
Z a a Official Agr. Chemists, 1921, 5: 37
id., 41.
332 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
nesium, etc.”! the methods for lead oxide and copper be adopted as
official methods and the method for zinc oxide be adopted as a tentative
method.
Approved.
(12) That the mercury-thiocyanate method for zine oxide in zinc
arsenite? be adopted as a tentative method.
Approved.
(13) That the official method for the determination of water-soluble
arsenic in lead arsenate? be adopted, under suspension of the rules, as
official for the determination of water-soluble arsenic in calcium arsenate.
This method involves the same principle and method of procedure as
are embodied in existing official methods for other materials.
Approved under suspension of the rules.
(14) That the official distillation method’ be adopted, under sus-
pension of the rules, as an official method for the determination of total
arsenic in magnesium arsenate. This method involves the same prin-
ciple and method of procedure as are employed in existing official methods
for other materials.
Approved under suspension of the rules.
(15) That a study be made of methods for the determination of
arsenious oxide, water-soluble arsenic and magnesium in magnesium
arsenate.
Approved.
SOILS.
SULFUR IN SOILS.
It is reeommended—
(1) That work be continued during the ensuing year in an effort to
perfect the tentative method or some other procedure which will insure
the complete recovery of total soil sulfur.
Approved.
1 J. Assoc. Official Agr. Chemists, 1921, 5: 42.
2 [bhid., 47.
3 Assoc. Official Agr. Chemists, Methods, 1920, 54.
>
1922] LYTHGOE: SUBCOMMITTEE B ON RECOMMENDATIONS OF REFEREES 333
REPORT OF SUBCOMMITTEE B ON RECOMMENDATIONS OF
REFEREES!.
By H. C. Lyrueor (State Department of Health, Boston, Mass.),
Chairman.
[Foods and feeding stuffs (crude fiber, stock feed adulteration, water), saccharine pro-
ducts (sugar, honey, maple products, maltose products, sugar-house products),
dairy products (moisture in cheese), testing chemical reagents, drugs
(alkaloids, arsenicals, synthetic drugs, alkaloids of opium,
medicinal plants, enzymes, sandalwood oil, balsam
and gum resins.)]
FOODS AND FEEDING STUFFS.
It is recommended that attention be given to the two following
recommendations from 1917 and 1919 which have not been acted upon:
(1) That a further study be made of sulfur dioxide in bleached grain.
(2) That the method for determining the acidity of corn, as described
by Black and Alsberg?, be considered by the referee next year with a
view to its adoption as an official method, and that the method be
studied to determine whether changes are necessary to make it applicable
to grains other than corn.
Your committee suggests that these two Pecoiumendations be referred
to the referee on foods and feeding stuffs.
Approved.
It is further reeommended—
(83) That the study of methods for the detection of ground bran in
shorts, as outlined in papers by J. B. Reed? and D. B. Bisbee* be further
studied during the coming year.
Approved.
CRUDE FIBER.
It is recommended—
(1) That the method for crude fiber be further studied.
Approved.
A motion was made by G. 8. Fraps that the words ‘‘or asbestos” be
inserted after the word “‘linen” in the official method for crude fiber®,
lines 8 and 13; and that the deletion of the first and second sentences in
the method for the determination of ether extract® be considered.
Your committee recommends that these questions be referred to the
referee on foods and feeding stuffs and the associate referee on crude
fiber respectively with directions to report at the next meeting.
Approved.
1 Presented by E. M. Bail
21S. Bur, Plant lod Bull, 199: (1910):
rare Official Agr. Chemists, 1921, 5: 70.
5 Assoc. oicial Agr. Chemists, Methods, 1920, 98, 66.
® Ibid., 72,
334 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
STOCK FEED ADULTERATION.
It is reeommended—
’ (1) That the method recommended by the associate referee on stock
feed adulteration! be further considered by the associate referee next
year with a view to its adoption as a tentative method.
Approved.
WATER.
Attention is called to the two following recommendations from 1919
which have not yet been acted upon:
(1) That the associate referee study the existing official general
methods for water in foods and feeding stuffs with a view to rewording
and fixing rigidly the conditions of temperature, pressure and other
factors.
(2) That a definite method applicable to the determination of water
in dried fruits be designed and submitted to the association.
Your committee recommends that these two recommendations be
referred to the referee on foods and feeding stuffs for consideration next
year.
Approved.
SACCHARINE PRODUCTS.
SUGAR.
Attention is called to the following 1916 and 1917 recommendations:
(1) That the modifications proposed in 1915 for determining sucrose
by acid and invertase inversion be further studied.
(2) That the work upon determining small amounts of reducing
sugars in the presence of sucrose be continued.
The committee suggests that these recommendations be referred to
the referee on saccharine products.
Approved.
HONEY.
No report or recommendations.
MAPLE PRODUCTS.
No report or recommendations.
MALTOSE PRODUCTS.
No report or recommendations.
SUGAR-HOUSE PRODUCTS.
It is recommended that the following 1919 recommendations be con-
tinued—
1 J. Assoc. Official Agr. Chemists, 1921, 5: 77.
1922] LYTHGOE: SUBCOMMITTEE B ON RECOMMENDATIONS OF REFEREES 335
(1) That a study be made of the influence of different and known
temperatures of incineration on the results of ash determinations in
cane sirups and molasses, carrying out the incineration in both plati-
num and silica dishes for comparison.
Approved.
(2) That a large number of samples of different grades of cane sirups
and molasses be used for comparing ash determinations by the sulfate
and direct methods, to determine, if possible, the proper correction
factor to be applied to the sulfated ash.
Approved.
DAIRY PRODUCTS.
It is recommended—
(1) That a further study be made of the alkaline acid modification of
the Roese-Gottlieb method as applied to dried milk products of various
fat content.
Approved.
(2) That a further study be made of the Roese-Gottlieb neutral
extraction method as applied to malted milk.
Approved.
(3) That a further study be made of a direct ether extraction method
as applied to malted milk.
Approved.
Attention is called to a recommendation in 1917 that the Schmidt-
Bondzynski method for the determination of fat in cheese be adopted
as Official. (First reading.) In 1919 it was recommended that this
method be further studied. Your committee would, therefore, rec-
ommend—
(4) That this method be reported upon by the referee next year.
Approved.
(5) That collaborative work be done upon the cryoscopic examination
of milk with a view to making the method official.
Approved.
MOISTURE IN CHEESE.
No report or recommendations.
-
TESTING CHEMICAL REAGENTS.
It is recommended—
(1) That this association declare itself in favor of cooperating with
the Committee on Guaranteed Reagents and Standard Apparatus of
the American Chemical Society in the collection of data in regard to
the quality of reagents on the market.
Approved.
(2) That the secretary of this association be instructed to transmit
a statement of this action to the proper official of each institution rep-
336 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
resented in the membership of the association and request that the
purchasing agent or some other official of the institution send him a
carbon copy of each letter written to a manufacturer or dealer calling
attention to a specific instance of delivery of an unsatisfactory reagent.
Approved.
DRUGS.
It is recommended—
(1) That a representative of this association be appointed to col-
laborate with the revision committee of the United States Pharmacopeeia
and report progress at the next annual meeting of the association.
Approved.
(2) That an associate referee be appointed to study the methods of
examination of acetylsalicylic acid reported by the referee', or any
method or methods that may be available elsewhere, for the purpose of
selecting or developing the most satisfactory method or methods of
analysis.
Approved.
(3) That an associate referee be appointed to study the methods for
the examination of phenolphthalein reported by the referee’, or any
method or methods that may be available elsewhere, for the purpose of
selecting or developing a satisfactory method or methods of analysis.
Approved.
(4) That an associate referee be appointed to study the methods for
the examination of camphor and camphor preparations reported upon
by the referee?, or any method or methods that may be available else-
where, for the purpose of selecting or developing a satisfactory method
or methods of analysis.
Approved.
(5) That an associate referee be appointed to study the methods for
the examination of mercurous chloride, mercuric chloride, and mercuric
iodide reported upon by the referee*, or any method or methods that may
be available elsewhere, for the purpose of selecting or developing satis-
factory methods of analysis.
Approved.
(6) That an associate referee be appointed to study the methods for
the detection of mineral oils in turpentine reported upon by the referee’,
or any method or methods that may be elsewhere available, for the
purpose of selecting or developing additional methods for the detection of
mineral oils in turpentine.
Approved.
1 J. Assoc. Official Agr. Chemists, 1921, 5: 141.
2 Tbid., 143.
§ Thid., 145.
4 Tbid., 148.
A PRRs
1922] LYTHGOE: SUBCOMMITTEE B ON RECOMMENDATIONS OF REFEREES 337
(7) That an associate referee be appointed to study the methods
of examination of papain reported by the referee!, or any method or
methods that may be elsewhere available, for the purpose of selecting
or developing satisfactory methods of analysis.
Approved.
ALKALOIDS.
It is reeommended—
(1) That the methods submitted for the separation of quinine and
strychnine be further studied by collaborators.
Approved.
(2) That the method for the assay of physostigma and its preparations
be studied by collaborators.
Approved.
(3) That the method for the assay of fluidextract of hyoscyamus be
studied by collaborators.
Approved.
(4) That the comparative study of volumetric and gravimetric
methods for the assay of ipecac be subjected to collaborative investiga-
tion.
Approved.
ARSENICALS.
It is recommended—
(1) That the methods reported by the associate referee? or any other
methods that may be otherwise available be studied with a view to
selecting a satisfactory method or methods of analysis.
Approved.
SYNTHETIC DRUGS.
It is reeommended—
That the method for the valuation of hexamethylenetetramine tablets
presented to the association in 1916 together with results of collaborative
work’ be adopted as tentative.
Approved.
(2) That the method of W. O. Emery for the estimation of mono-
bromated camphor in migraine tablets‘ be studied cooperatively; and
that the method of E. O. Eaton be studied further.
Approved.
(3) That the method of S. Palkin for the determination of phenol-
phthalein® be studied cooperatively and that further study be made of
other methods.
Approved.
1J. ee: aera Agr. Chemists, 1921, 5: 146.
See eisee
J. Ind. Eng. Chem., A018, 11: 756.
6 Tbid., 1920, 12: 766.
338 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(4) That the method submitted for the examination of procaine! be
studied by collaborators during the coming year.
Approved.
ALKALOIDS OF OPIUM.
It is reeommended—
(1) That the methods submitted by the associate referee for the
examination of morphine, codeine, and heroine? be studied by col-
laborators.
Approved.
MEDICINAL PLANTS.
It is reeommended—
(1) That further work be done on the value of weights of unit volumes
or the specific weight of crude drugs and spices.
Approved.
(2) That the subject of sublimation for analysis of plant products,
etc., be further studied.
Approved.
(3) That the methods for the macroscopic and microscopic identifi-
cation of Digitalis thapsit (Spanish digitalis), a recent substitute for
Digitalis purpurea, and Hyoscyamus muticus (Egyptian henbane), a
substitute for Hyoscyamus niger, be studied by collaborators.
Approved.
(4) That the method for the detection of the presence of santonin in
wormseed (Artemisia cina), and subsequent isolation, be studied by
collaborators.
Approved.
(5) That the method for the use of pollen grains as a means of identi-
fication and differentiation of plants and plant products be further studied,
Approved.
(6) That further information be collected concerning adulterants
and substitutes of crude drugs and spices.
Approved.
ENZYMES.
No report or recommendations.
SANDALWOOD OIL.
It is recommended—
(1) That the methods submitted by C. W. Harrison at the 1919
meeting for the determination of the acetyl value of sandalwood oil®
be further studied by collaborators.
Approved.
1 J. Assoc. Official Agr. Chemists, 1921, 5: 164.
50.
2 [bid., 15
§ [bid., 4: 425.
1922] DOOLITTLE: COMMITTEE C ON RECOMMENDATIONS OF REFEREES 339
BALSAM AND GUM RESINS.
It is recommended that the following 1919 recommendation be re-
ferred to the referee on drugs for next year.
(1) That further collaborative work be done upon the method sub-
mitted for the determination of crude fiber in gum karaya.
Approved.
‘REPORT OF SUBCOMMITTEE C ON RECOMMENDATIONS OF
REFEREES.
By R. E. DoouittLe (Transportation Building, Chicago, IIl.), Chairman.
[Food preservatives (saccharin), coloring matters in foods, metals in foods, fruits and
fruit products (pectin in fruit products), canned foods (physical methods of
examination, tomato products), cereal foods, wines, distilled liquors, beers
(limits of accuracy in the determination of small amounts of alcohol),
methods of analysis of near beers, soft drinks (bottlers’ products),
vinegars, flavoring extracts, meat and meat products (separa-
tion of meat proteins, decomposition of meat products,
gelatin), fats and oils, eggs and egg products, spices,
cacao products (determination of shells,
examination of cacao butter), coffee,
tea, baking powder.]
FOOD PRESERVATIVES (SACCHARIN).
No report or recommendations received from the referee. Your
committee, however, recommends that the following recommendations
adopted at the 1917 and 1919 meetings, be continued.
(1) That further work be done on the method for the determination
of saccharin in the presence of mustard oil'.
Approved.
(2) That other methods not dependent upon the sulfur component
of saccharin be investigated.
Approved.
(3) That further work be done upon the determination of saccharin
in baked flour preparations. ;
Approved.
COLORING MATTERS IN FOODS.
It is reeommended—
(1) That the methods submitted by the referee? for the determination
of moisture, total matter insoluble in water, inorganic or nonvolatile
matter insoluble in water, total matter soluble in water, matter insoluble
in carbon tetrachloride, sodium chloride, sodium sulfate, sulfated ash,
heavy metals, calcium, arsenic by direct precipitation, arsenic after
1 J. Assoc. Official Agr. Chemists, 1920, 3: 505.
2Tbid., 1921, 5: 196.
340 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
treatment with nitric acid, total arsenic, sulfur, nitrogen, total halo-
gens, total iodine, sodium iodide, ether extractives, dye by titration
with titanium trichloride, dye by titration with potassium permanga-
nate, dye by colorimetric comparison, lower sulfonated dyes, melting
point, Martius Yellow and Naphthol Yellow S, boiling point of Cumi-
dine from Ponceau 3R, Orange II and Orange I, Iodeosine G in Ery-
throsine, and isomeric and similar dyes in Amaranth for the examina-
tion of commercial food colors be adopted as tentative and that they be
subjected to collaborative study during the coming year with a view to
the adoption by the association as official methods for the examination
of commercial food colors.
Approved.
(2) That further study be made of methods applicable to the separa-
tion of the oil-soluble coal tar food colors from fats and oils.
Approved.
(3) That work on the common natural colors be continued.
Approved.
(4) That the referee give consideration to the tentative methods on
coloring matters in foods, Chapter X', during the coming year for the
purpose of recommending such as are considered suitable for adoption
as official methods.
Approved.
METALS IN FOODS.
It is reeommended—
(1) That the tentative methods for copper and zinc?, together with
any other apparently desirable methods, be studied by collaborative
work during the coming year.
Approved.
(2) That the Gutzeit method and apparatus for the determination
of arsenic, described by H. V. Farr but as yet unpublished, be studied
by collaborative work in comparison with the present Gutzeit method.
Approved.
(3) That the Penniman method for tin’ be studied further with a
view to revision or radical modification and that collaborative study be
made of any promising procedure that may be developed.
Approved.
(4) That metals for which no methods had been suggested be studied
in the order of their toxicity, the likelihood of their occurrence in foods
being given first consideration.
Approved.
(5) That the attention of the referee be called to the action by the
1 Assoc. Official Agr. Chemists, Methods, 1920, 131.
2 Thid., 151.
* J. Assoc. Official Agr. Chemists, 1920, 4: 172.
1922] DOOLITTLE: COMMITTEE C ON RECOMMENDATIONS OF REFEREES 341
association at the 1919 meeting, making the gravimetric method and
the volumetric method for the determination of tin, official methods.
(First action.)
Approved.
FRUITS AND FRUIT PRODUCTS.
It is recommended—
_ (1) That the methods submitted by F. B. Power! for the detection
of methyl anthranilate in fruit juices be referred to the referee for col-
laborative study during the coming year.
Approved.
PECTIN IN FRUIT AND FRUIT PRODUCTS.
It is reeommended—
(1) That further investigation be made of methods for the detection
of pectin in jellies, jams and similar fruit products.
Approved.
CANNED FOODS.
It is recommended—
(1) That the investigation of methods for the detection of spoilage
and for distinguishing conditions which are likely to lead to spoilage
be continued.
Approved.
PHYSICAL METHODS OF EXAMINATION.
No report or recommendations.
TOMATO PRODUCTS.
No report or recommendations.
CEREAL FOODS.
It is reeommended—
(1) That the work on the determination of moisture, gluten, soluble
carbohydrates, cold water extract, chlorine and ash be continued.
Approved. :
(2) That the referee study methods for the determination of fat in
baked cereal products.
Approved.
WINES.
No report or recommendations.
DISTILLED LIQUORS.
No report or recommendations.
1 J. Am. Chem. Soc., 1921, 43: 377.
342 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
BEERS (LIMITS OF ACCURACY IN THE DETERMINATION OF SMALL
AMOUNTS OF ALCOHOL).
It is recommended—
(1) That the study of the method for the determination of alcohol
to determine limits of accuracy be continued.
Approved.
NEAR BEERS.
No report or recommendations.
SOFT DRINKS (BOTTLERS’ PRODUCTS).
It is recommended—
(1) That the study of methods for the examination of this class of
products be continued. ;
Approved.
VINEGARS.
It is recommended—
(1) That the methods for the determination of glycerol, solids, and
fixed acids be studied during the coming year.
Approved.
FLAVORING EXTRACTS.
It is recommended—
(1) That a study of methods for the analysis of imitation vanilla
preparations containing large quantities of coumarin and vanillin be
made.
Approved.
(2) That the method suggested by Penniman and Randall for the
determination of oil in lemon and orange extracts! be studied in con-
nection with the official method.
Approved.
(3) That a study of methods for the examination of non-alcoholic
extracts be made.
Approved.
(4) That the method adopted at the 1919 meeting of the association
as an official alternative method (first action) for the determination of
alcohol in orange and lemon extracts consisting only of alcohol, oil and
water? be subjected to collaborative study with a view to recommend-
ation for final action at the 1921 meeting.
Approved.
MEAT AND MEAT PRODUCTS.
It is recommended—
(1) That the method for the determination of sugar in meat and
1J. Ind. Eng. Chem., 1914, 6: 926.
2 [bid., 1909, 1: 84.
—
eT a at
1922] DOOLITTLE: COMMITTEE C ON RECOMMENDATIONS OF REFEREES 343
meat products', adopted at the 1919 meeting as tentative, be subjected
to collaborative study during the coming year.
Approved.
SEPARATION OF MEAT PROTEINS.
It is recommended that the two following recommendations adopted
at the 1919 meeting be continued.
(1) That further work be done on the Schlésing-Wagner method for
the determination of nitrates, using beef extract, and other meat pro-
ducts.
Approved.
(2) That the associate referee attempt to determine the relative
amounts of the dissociation products in water-soluble and water-insoluble
meat proteins.
Approved.
(3) That the attention of the associate referee be called to the action
taken by the association at the 1919 meeting whereby the ferrous chloride
method for the determination of nitrates was changed to express the
results in terms of sodium nitrate while no action was recommended by
the associate referee in connection with the phenoldisulfonic acid method
for the same determination.
Approved.
DECOMPOSITION OF MEAT PRODUCTS.
No report or recommendations.
GELATIN.
It is recommended—_
(1) That the methods, submitted by the referee shortly after the
adjournment of the 1919 meeting, for the determination of moisture,
ash, total phosphorus, nitrogen, arsenic, copper, lead, zinc, polariscopic
constants, and sulfur dioxide for the examination of gelatin be adopted
as tentative methods, and that these methods be referred to the asso-
ciate referee for collaborative study during the coming year.
Approved. i
These methods are as follows:
Moisture.
(a) Proceed as directed under VII, 32.
(b) Dry in water oven at 100°C. for 6 hours. Cool in a vacuum desiccator admit-
ting air dried by passing through concentrated sulfuric acid and weigh rapidly with
dish covered.
(C) Dry in vacuum oyen at 70°C. and cool in a vacuum desiccator admitting air
as in (b).
1 Assoc. Official Agr. Chemists, Methods, 1920, 213.
2 Ibid., 71.
344 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Ash.
Ash at low redness preferably in a muffle as directed under VII, 4.
Total Phosphorus.
Treat the ash obtained as above with 2-3 cc. of nitric acid (sp. gr. 1.42) and evaporate
on the steam bath. Repeat the nitric acid treatment and take up in hot water con-
taining a few drops of nitric acid and proceed as directed under I, 67.
Nitrogen.
Proceed as directed under XX, 63.
Arsenic’.
Heat 20 grams of gelatin with 75 cc. of arsenic-free hydrochloric acid, 1 to 3,in a
covered vessel until all insoluble matter has flocculated and the gelatin dissolved.
Add an excess of bromine water (about 20 cc.), neutralize with ammonium hydroxide;
add either about 14 cc. of 85% phosphoric acid or 2 grams of sodium phosphate (Nas-
HPO,.12H.0), or crystallized sodium ammonium phosphate and allow to cool.
Precipitate the arsenic acid along with the phosphoric acid by an excess of magnesia
mixture (cf. I, 4, (c))5. The phosphoric acid or compound used should require about
20-25 cc. of the usual magnesia mixture for precipitation. After standing about an
hour, wash the precipitate several times with dilute ammonium hydroxide, drain well
and dissolve in dilute hydrochloric acid, 1 to 3, to 50 cc. volume ina graduated flask.
Take a 25 cc. aliquot and determine the arsenic as directed under XI, 4°. Run a
blank determination with the sample. Arsenic impurities, if present, are usually
found in the phosphate added.
Copper.
Hydrolize 50 grams of gelatin with 150 cc. of dilute hydrochloric acid, 1 to 3, as
directed under arsenic, heating about 2 hours on the steam bath. To facilitate filtra-
tion and separation from zinc and iron later, use the phosphoric acid or compound and
magnesia mixture as before. Precipitate with hydrogen sulfide in a slightly ammoniacal
solution. Allow the precipitate to settle, filter and wash with 5% ammonium chloride
solution saturated with hydrogen sulfide. Dissolve off the zine and iron sulfides,
magnesium phosphate, etc., in 75 cc. of dilute hydrochloric acid (4% HCl) saturated
with hydrogen sulfide. Digest filter and copper sulfide with 4 cc. of concentrated
sulfuric acid and sufficient nitric acid until the residue is perfectly colorless and fuming
freely. Take up with water and determine copper by titrating with 0.01N sodium
thiosulfate as directed under VII, 28’.
Lead.
If lead is present, it is shown as the sulfate mixed with some silica when the sulfuric
acid residue is diluted with water in the above determination. Add an equal volume
of alcohol and allow to stand several hours. Filter and wash with dilute alcohol. Evap-
orate the filtrate to remove alcohol and determine copper as directed under VIT, 28’.
Dissolve the lead sulfate from the filter with 10 cc. of hot 50% ammonium acetate
solution alternated with hot water until the filtrate measures about 75 cc. Add pot-
1 Assoc. Official Agr. Chemists, Methods, 1920, 71.
2 Thid., 2.
8 Thid., 209.
4U.S. Bur. Chem. Cire. 102; J. Soc. Chem. Ind., 1907, 26: 1115.
5 Assoc. Official Agr. Chemists, Methods, 1920, 2.
6 Ihid., 148.
7 Ibid., 79.
aaa g
—-
1922] DOOLITTLE: COMMITTEE C ON RECOMMENDATIONS OF REFEREES 345
assium dichromate solution to precipitate the lead as chromate, filter on a Gooch, dry
at 125-150°C. and weigh. Calculate to metallic lead using the factor 0.641.
Zine.
Determine the zinc in filtrate from copper determination as directed under XI, 91,
or as directed below beginning with “Boil the filtrate, etc.”’
Alternate Method for Copper and Zinc’.
Hydrolize 20-50 grams of gelatin with 100 cc. of dilute hydrochloric acid, 1 to 3>
for 2 hours on the steam bath. Add 5 mg. of iron from 5 cc. of a standard solution of
ferrous sulfate (4.9 grams of ferrous sulfate to a liter containing 10 cc. of sulfuric acid).
Make solution faintly ammoniacal and saturate with hydrogen sulfide. Filter the
sulfides and wash 2 or 3 times with a very dilute solution of colorless ammonium sulfide
(saturate a solution of 1 cc. of concentrated ammonium hydroxide in 200 cc. of water).
Dissolve the sulfides in 20 cc. of hot, dilute nitric acid, 1 to 1, and wash filter and
insoluble matter with water. Add 10 cc. of dilute sulfuric acid, 1 to 3, and evaporate
all the nitric acid. Cool and add 40 cc. of water. When the soluble salts are in solution
filter off silica, washing filter thoroughly with water. Saturate the filtrate with hydro-
gen sulfide. Heat the solution 5 minutes on the steam bath. Filter the copper sulfide
on a carefully prepared Gooch crucible and wash with hydrogen sulfide water. Dry
and ignite to copper oxide. ‘
Boil the filtrate to expel all hydrogen sulfide. Make the solution strongly am-
moniacal and then acidify with 15 cc. of 50% formic acid. Filter off any insoluble
matter such as alumina, etc., while hot, and then pass in a rapid stream of hydrogen
sulfide for 10 minutes. Warm solution 15 minutes on the steam bath, remove and
allow to stand for 30 minutes before filtration. Filter the zinc sulfide on a carefully
prepared Gooch crucible with a very gentle suction, washing with 2% ammonium
thiocyanate. Dry and ignite at the highest temperature of a Bunsen burner. Cool
and weigh the zinc oxide.
Polariscopie constants.
Prepare a concentration of 3 grams per 100 cc. by soaking 3 grams of the sample in
40-50 cc. of cold water for about 15 minutes, heating to complete solution at about
50°C. and making to volume at 35°C. Polarize at 35°C. in a 2 dm. tube using the
Ventszke scale.
Cool a portion of the gelatin solution rapidly to 10-15°C. and pour into cold, dry
1 dm. tubes before jelly has had time toform. Place the tube in a constant tempera-
ture bath at 15°C. and polarize after 18 hours to obtain equilibrium rotation at 15°C.
Double the reading to place it on basis of 2 dm. tube.
In order to polarize cloudy samples, digest the original 100 cc. in a stoppered flask
with roughly 10 cc. of lightly powdered magnesium carbonate for at least 1 hour at
35—40°C. and filter until clear through a folded filter, avoiding unnecessary evapora-
tion.
The increase in levorotation (mutarotation) between 35° and 15° is an index of the
jelly strength developed.
Sulfur diozide.
Proceed as in the distillation method under IX, 31° or by the diffusion method as
follows: Cool, in ice water, a vessel containing 100-150 cc. of water, 5 cc. of dilute
hydrochloric acid, 1 to 3, 10 grams of sodium chloride and some filtered starch solution.
1 Assoc. Official Agr. Chemists, vlad a 1920, 151.
2 J. Ind. Eng. Chem., 1919, 11: 323
* Assoc. Official Agr. Chemists, Methods, 1920, 127,
346 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Add a few drops of 0.01N iodine until a blue color is produced. Pour this mixture on
5 grams of powdered gelatin sample contained in a stoppered flask, replacing in the
ice water. After remaining for 2 minutes with occasional mixing, add 0.01N iodine
until the blue color is restored. Replace in the ice water for one minute, remove and
titrate to the reappearance of the color. Repeat these operations until the color per-
sists for 1 minute.
One cc. of 0.01N iodine is equivalent to 0.32 milligram of sulfur dioxide.
FATS AND OILS.
It is recommended—
(1) That the Wijs method for the determination of iodine absorption
number! be made official. (First reading.)
Approved
EGGS AND EGG PRODUCTS.
It is reeommended—
(1) That the method presented by the referee for the determination
of zinc in dried egg products? be made a tentative method and that it
be referred to the referee for collaborative study during the coming
year.
Approved.
(2) That the W. G. McGeorge method for the determination of zine
in dried egg products* be studied during the coming year.
Approved.
(3) That the study of the methods for the determination of lecithin-
phosphoric acid in dried eggs and alimentary pastes be continued.
Approved.
SPICES.
It is reeommended—
(1) That the studies of the distillation method for the determination
of water in whole spices be continued.
Approved.
(2) That the method for the determination of volatile oil in mustard
seed’, which was adopted as an official method (first reading) at the 1919
meeting, be subjected to collaborative study during the coming year
with a view to its presentation for final action, if possible, at the 1921
meeting.
Approved.
(3) That the paper, entitled “‘Salad Dressings and Their Analyses”,
by H. A. Lepper®, be referred to the referee on spices for the study of
the methods contained therein.
Approved.
1 Assoc. Official Agr. Chemisls, Methods, 1920, 245.
2 J. Assoc. Official Agr. Chemists, 1921, 5: 192.
3 Thid., 194.
' Assoc. Official Agr. Chemists, Methods, 1920, 259.
5 J. Assoc. Official Agr. Chemists, 1921, 5: 248.
a
|
1922] DOOLITTLE: COMMITTEE C ON RECOMMENDATIONS OF REFEREES 347
(4) That the method for the detection of molds in drugs, foods and
spices, by means of the chitin test! be adopted as a tentative method.
Approved.
CACAO PRODUCTS.
DETERMINATION OF SHELLS.
It is recommended—
(1) That the microscopic methods for the estimation of shells in cacao
products be studied further.
Approved.
(2) That the chemical methods, particularly crude fiber, for the
estimation of shells be studied in order to determine whether conclusions
drawn from these methods may be correlated with those obtained by
the microscopic examination.
Approved.
(3) That the paper, entitled “Cacao Products with Special Reference
to Shell Content’, by B. H. Silberberg?, be referred to the referee on
the determination of shells in cacao products for his information and
study of methods.
Approved.
(4) That the association recommend to the Committee on Coopera-
tion with Other Committees on Food Definitions a modification of the
standards on cacao products’. Your committee does not approve this
recommendation but suggests that the referee refer his data and in-
information directly to the Secretary of the Joint Committee on Defi-
nitions and Standards.
Committee recommendation approved.
CACAO BUTTER.
It is recommended—
(1) That further collaborative work be done on the critical tem-
perature of dissolution method, especially to test the accuracy of the
correction factor for acidity.
Approved.
(2) That the tests for tallow, hydrogenated oils, lard, paraffin, etc.,
be further studied.
Approved.
COFFEE.
It is reeommended—
(1) That the Power-Chesnut method for the determination of caffeine
in coffee‘ be adopted as an official method. (First reading.)
Approved.
Shear Official Agr. Chemists, 1921, 5: 156.
iy
3U.S. Dept. of Agr., Office of the Seren Circ. 136: (1919), 18.
4 J. Assoc. Official ‘Agr. Chemists, 1921, 5: 271
348 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(2) That the Fendler-Stiiber method for the determination of caffeine
in coffee be retained as a tentative method and be designated as a
method to be used when quick results are desired.
Approved.
(3) That the Stahlschmidt method for the determination of caffeine
in coffee be dropped from the official and tentative methods.
Approved.
(4) That the referee study methods for the determination of other
constituents of coffees.
Approved.
(5) That the paper, entitled ““Robusta Coffee’, by A. Viehoever and
H. A. Lepper’, be referred to the referee for his information and study
of methods.
Approved.
TEA.
It is recommended—
(1) That the modified Stahlschmidt method for the determination
of caffeine in tea? be not made official this year.
Approved.
(2) That the Power-Chesnut method for the~ determination of
caffeine in tea’ be made official. (First reading.)
Approved.
(8) That the proposed method for the determination of caffeine* be
studied collaboratively during the coming year.
Approved.
BAKING POWDERS.
It is recommended—
(1) That a further study be made of the Chittick method® for the
determination of lead in baking powder with a view to establishing it
as a tentative method.
Approved.
(2) That a study be made of the details of the electrolytic method
for the determination of lead in baking powder with special reference
to the acidity conditions during electrolysis.
Approved.
(3) That a study be made of methods for the determination of the
neutralizing strength of baking acids.
Approved.
(4) That the method for the determination of fluorine in baking
1J. Assoc. Official Agr. Chemists, 1921, 5: 274.
2 Assoc. Official Agr. Chemists, Methods, 1920, 270.
3 J. Assoc. Official Agr. Chemists, 1921, 5: 290.
‘4 Thid., 291.
5 J. Assoc. Official Agr. Chemists, 1920, 4: 218.
1922] REPORT OF COMMITTEE ON RESOLUTIONS 349
powder and phosphates adopted as a tentative method at the 1919
meeting! be subjected to collaborative study during the coming year.
Approved.
_ (5) That the paper, entitled “Determination of Total Carbon Dioxide
in Baking Powder’’, by C. S. Robinson, be referred to the referee on
baking powder for study of the method contained therein.
Approved.
REPORT OF THE COMMITTEE TO COOPERATE WITH OTHER
COMMITTEES ON FOOD DEFINITIONS?®.
Your committee has no formal report to present. Because of the
withdrawal from the committee of three of its members, E. F. Ladd,
F. C. Blanck, and J. S. Abbott, no sessions of the committee have been
held since the last meeting of this association. Work is progressing
on a number of subjects, however, particularly canned foods, but has
not reached such a stage that it can be reported at this time.
Respectfully submitted,
WILurAM FREaR,
Jutius Hortvet,
C. D. Howarp.
Committee to Cooperate with Other Committees
on Food Definitions.
President Lythgoe read a letter from H. E. Howe, Chairman of the
Division of Research Extension of the National Research Council,
inviting this association to appoint two members to serve on the Board
of Trustees of the Crop Protection Institute. A motion was made,
seconded and duly carried that this matter be referred to the incoming
Executive Committee with power to act.
Adopted.
REPORT OF COMMITTEE ON RESOLUTIONS’.
Since the 1919 meeting of this association, word has come to your
committee of the death of two valued members.
Albert F. Seeker, for some years Chief of the New York Food and
Drug Inspection Station of the Bureau of Chemistry, died on August 19,
1919, from an attack of appendicitis. A skilful analyst and a chemist
of unusually broad information in the domain of this science, Mr. Seeker
performed service of conspicuous value to this association as referee on
1 J. Assoc. Official Agr. Chemists, 1921, 4: 585.
2 Tbid., 5: 182.
3 Presented by William Frear.
350 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
the subjects of spices, flavoring extracts and food preservatives, and, as
a member of the Committee on Editing Methods of Analysis, bore a
heavy share of that responsibility.
Your committee recommends the adoption of the following reso-
lution:
Resolved, That in the death of Albert F. Seeker this association has
lost a member who for years made contributions of very high value to
its work, and its members, a friend who had won the esteem of all for
his quiet manliness and his spirit of helpfulness.
Resolved, That the editor of The Journal be requested to print an
appropriate notice of Mr. Seeker’s work and death.
In January, 1920, after an illness of a few days, died Hugh A. Bryan,
at that time Chief Chemist to Arbuckle and Company. Dr. Bryan, as
chief chemist of the Sugar Laboratory of the Bureau of Chemistry, was
for years an active member of this association. He won the high regard
of the members for his geniality and his studious industry, and rendered
invaluable service to the association as its referee on sugar and related
products. An account of the life and service of Dr. Bryan has already
appeared in this Journal!.
Your committee recommends the adoption of the following resolution:
Resolved, That in the death of Dr. Hugh A. Bryan, this association
has lost a highly prized associate member, from whom during his years
of active membership it received signal aid in its work upon sugar
chemistry, and from whom, as a fellow analyst in the prime of his power,
his associates had confidently expected further scientific contributions
of great value.
Resolved, That the secretary of the association be directed to send
copies of these resolutions of appreciation to the families of the deceased
members. :
Resolved, That the Association of Official Agricultural Chemists hereby
expresses to the Honorable Edwin T. Meredith, Secretary of Agri-
culture, its thanks for his address before this body, and particularly for
his appreciation of the worth of the services of this association to the
work of his department and to agricultural progress.
Resolved, That a vote of thanks be extended by the association to our
President, Mr. Hermann C. Lythgoe, for the admirable manner in which
he has conducted the proceedings of this convention.
Resolved, That this association extend a vote of appreciation and
thanks to its secretary and to his faithful assistant, Miss N. A. Parkin-
son, for the able manner in which they have performed their work in
connection with this convention, for their excellent services in the
1J. Assoc. Official Agr. Chemists, 1920, 3: iii.
1922] : REPORT OF COMMITTEE ON RESOLUTIONS 351
handling and preparation of our reports for publication in The Journal,
and also for their supervisory work in connection with the publication
of the Official and Tentative Methods of Analysis.
Resolved, That this association extend its hearty thanks to the Board
of Editors and to the Committee on Editing Methods of Analysis for
the able and faithful manner in which they have performed the arduous
duties imposed on them.
Resolved, That the Association of Official Agricultural Chemists
extend its thanks to the management of the New Willard Hotel for
the use of the ball room and for the other conveniences which have
been granted to the association, and for the many courtesies which
have been extended to our members.
Resolved, That the secretary be and is hereby directed to transmit to
each of the respective persons named in these resolutions, a copy of the
appropriate resolution.
Respectfully submitted,
WILLIAM FREAR,
Junius Hortvet,
E. W. MacrupeEr.
Committee on Resolutions.
The convention adjourned.
PROCEEDINGS OF THE THIRTY-SEVENTH AN-
NUAL CONVENTION OF THE ASSOCIATION
OF OFFICIAL AGRICULTURAL
CHEMISTS, 1921.
OFFICERS, COMMITTEES, REFEREES, AND ASSOCIATE
REFEREES OF THE ASSOCIATION OF OFFICIAL
AGRICULTURAL CHEMISTS, FOR THE YEAR
ENDING OCTOBER, 1922.
Honorary President.
H. W. Witey, Woodward Building, Washington, D. C.
President.
F. P. Verrcu, Bureau of Chemistry, Washington, D. C.
Vice-President.
A. J. Parren, Agricultural Experiment Station, E. Lansing, Mich.
Secretary-Treasurer.
W. W. Sxuvner, Bureau of Chemistry, Washington, D. C.
Additional Members of the Executive Committee.
H. D. Haskins, Agricultural Experiment Station, Amherst, Mass.
R. E. DoouittLe, Transportation Building, Chicago, Ill.
PERMANENT COMMITTEES.
Cooperation with Other Committees on Food Definitions.
William Frear (State College, Pa.), Chairman.
Julius Hortvet, St. Paul, Minn.
C. D. Howard, Concord, N. H.
Membership of Committee to Cooperate in Revision of the U. S. Pharmacopeia.
L. F. Kebler (Bureau of Chemistry, Washington, D. C.), Chairman.
H. C. Lythgoe, Boston, Mass. A. R. Bliss, Emory University, Ga.
H. C. Fuller, Washington, D. C. W.S. Hubbard, New York, N. Y.
352
1922] REFEREES AND ASSOCIATE REFEREES 353
Recommendations of Referees.
(Figures in parenthesis refer to year in which appointment expires.)
R. E. Dooutrtte (Transportation Building, Chicago, Ill.), Chairman.
Suspcommittee A: B. B. Ross (1926), (Polytechnic Institute, Auburn, Ala.), Chairman,
W. H. MacIntire (1924), C. C. McDonnell (1922). [Fertilizers (borax in fertilizers,
preparation of ammonium citrate, nitrogen, potash, potash availability, pre-
cipitated phosphates), inorganic plant constituents, (sulfur and phosphorus in
the seeds of plants, calcium and magnesium in the ash of seed), water, tanning
materials and leather, insecticides and fungicides, and soils (sulfur in soils).]
SuscommitTeeE B: H. C. Lythgoe (1926), (State Department of Public Health, Boston,
Mass.), Chairman, E. M. Bailey (1924), C. A. Browne (1922). [Foods and feed-
ing stuffs (crude fiber, stock feed adulteration), saccharine products (honey, maple
products, maltose products, sugar-house products), dairy products (moisture in
cheese, cryoscopic examination of milk, methods for fat in malted and dried milk),
fats and oils, baking powder (fluorides in baking powder), drugs (examination of
arsphenamine and neoarsphenamine; determination of alcohol in drug prepara-
tions; analytical methods for the determination of chloral hydrate in drug prepara-
tions; analytical methods for the determination of silver in silver proteinates;
determination of camphor in pills and tablets by the alcohol distillation method;
distillation method for the estimation of santalol in santal oil; turpentine; crude
drugs; alkaloids; methods of analysis of morphine, codeine and diacetylmorphine;
laxative and bitter tonic drugs; the determination of calomel, mercuric chloride
and mercuric iodide in tablets; the analysis of acetylsalicylic acid; methods for the
examination of phenolphthalein; method for the analysis of monobromated cam-
phor; methods for the separation and estimation of the principal cinchona alkaloids;
differentiation of Japanese and American peppermint oils), testing chemical
reagents, nonalcoholic beverages, and eggs and egg products.]
Suscommaitree C: R. E. Doolittle (1926), (Transportation Building, Chicago, Il.),
Chairman, W. C. Geagley (1924), W. W. Randall (1922). [Food preservatives
(saccharin), coloring matters (oil-soluble colors), metals in foods (arsenic), pectin
in fruits and fruit products, moisture in dried fruit, canned foods, cereal foods,
limit of accuracy in the determination of small amounts of alcohol in beers, vine-
gars, flavoring extracts, meat and meat products (separation of meat proteins,
decomposition of meat products, gelatin), spices, determination of shells in cacao
products, methods for the examination of cacao butter, coffee, tea, and nitrogen
in foods.]
Board of Editors. %
R. W. Balcom (Box 290, Pennsylvania Avenue Station, Washington, D. C.), Chairman.
C. B. Lipman (1922). William Frear (1924).
R. E. Doolittle (1923). R. B. Deemer (1925).
Marian E. Lapp, Associate Editor.
Editing Methods of Analysis.
R. E. Doolittle (Transportation Building, Chicago, Ill.), Chairman.
B. B. Ross. J. W. Sale.
A. J. Patten. G. W. Hoover.
W. H. MaclIntire.
354 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
SpEcIAL COMMITTEES.
Vegetation Tests on the Availability of Phosphoric Acid in Basic Slag.
H. D. Haskins (Agricultural Experiment Station, Amherst, Mass.), Chairman.
C. B. Williams. B. L. Hartwell.
W. B. Ellett. J. A. Bizzell.
Committee to Cooperate with the American Sociely for Testing Materials on the Subject of
Agricultural Lime.
W. H. MaclIntire (Agricultural Experiment Station, Knoxville, Tenn.), Chairman.
William Frear. F. P. Veitch.
Committee on Revision of Methods of Soil Analysis.
C. B. Lipman (Agricultural Experiment Station, Berkeley, Calif.), Chairman.
W. H. MacIntire. R. Stewart.
A. W. Blair. J. A. Bizzell.
Committee on Quartz-Plate Standardization and Normal Weight.
Frederick Bates (Bureau of Standards, Washington, D. C.), Chairman.
C. A. Browne. F. W. Zerban.
Representative to Cooperate with the Revision Committee of the United States
Pharmacopeia.
L. F. Kebler, Bureau of Chemistry, Washington, D. C.
Representatives on the Board of Governors of the Crop Protection Institute of the National
Research Council.
B. L. Hartwell, Kingston, R. I.
H. J. Patterson, College Park, Md.
Referees and Associate Referees.
Fertilizers:
Referee: R. N. Brackett, Clemson Agricultural College, Clemson College, S. C.
Boraz in Fertilizers:
Associate referee: J. M. Bartlett, Agricultural Experiment Station, Orono, Me.
Preparation of ammonium citrate:
Associate referee: C. S. Robinson, Agricultural Experiment Station, E. Lan-
sing, Mich.
Nitrogen:
Associate referee: I. K. Phelps, Bureau of Chemistry, Washington, D. C.
Potash:
Associate referee: J. T. Foy, Clemson Agricultural College, Clemson College,
S..G;
Potash availability:
Associate referee: A. G. McCall, Agricultural Experiment Station, College
Park, Md.
Precipitated phosphates:
Associate referee: H. D. Haskins, Agricultural Experiment Station, Amherst,
Mass.
1922] REFEREES AND ASSOCIATE REFEREES 355
Inorganic plant constituents:
Referee: A. J. Patten, Agricultural Experiment Station, E. Lansing, Mich.
Sulfur and phosphorus in the seeds of plants:
Associate referee: W. L. Latshaw, Agricultural Experiment Station, Man-
hattan, Kans.
Calcium, magnesium, iron, and aluminium in the ash of seed:
Associate referee: A. J. Patten, Agricultural Experiment Station, E. Lansing,
Mich.
Water:
Referee: J. W. Sale, Bureau of Chemistry, Washington, D. C.
Tanning materials and leather:
Referee: F. P. Veitch, Bureau of Chemistry, Washington, D. C.
Insecticides and fungicides:
Referee: J. J. T. Graham, Bureau of Chemistry, Washington, D. C.
Soils:
Referee: W. H. MacIntire, Agricultural Exneriment Station, Knoxville, Tenn.
Sulfur in soils:
Associate referee: W. H. MacIntire, Agricultural Experiment Station, Knox-
ville, Tenn.
Foods and feeding stuffs:
Referee: J. B. Reed, Bureau of Chemistry, Washington, D. C.
Crude fiber:
Associate referee: G. S. Fraps, Agricultural Experiment Station, College
Station, Texas.
Stock feed adulteration:
Associate referee: H. E. Gensler, State Department of Agriculture, Harris-
burg, Pa.
Saccharine products:
Referee: H. S. Paine, Bureau of Chemistry, Washington, D. C.
Honey:
Associate referee: S. F. Sherwood, Bureau of Plant Industry, Washington, D.C.
Maple products:
Associate referee: C. H. Jones, Agricultural Experiment Station, Burlington,
Wit
Malltose products:
Associate referee: O. S. Keener, Bureau of Chemistry, Washington, D. C.
Sugar-house products:
Associate referee: J. F. Brewster, Sugar Experiment Station, New Orleans, La.
356 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Dairy products:
Referee: Julius Hortvet, State Dairy and Food Commission, St. Paul, Minn.
Moisture in cheese:
Associate referee: L. C. Mitchell, U. S. Food and Drug Inspection Station,
310 Federal Office Building, Minneapolis, Minn.
Cryoscopic examination of milk:
Associate referee: E. M. Bailey, Agricultural Experiment Station, New Haven,
Conn.
Methods for fat in malted milk and dried milk:
Associate referee: J. T. Keister, Bureau of Chemistry, Washington, D. C.
Fats and oils:
Referee: G. S. Jamieson, Bureau of Chemistry, Washington, D. C.
Baking powder:
Referee: L. H. Bailey, Bureau of Chemistry, Washington, D. C.
Fluorides in baking powder:
Associate referee: J. K. Morton, Bureau of Chemistry, Washington, D. C.
Drugs:
Referee: G. W. Hoover, U. S. Food and Drug Inspection Station, Transportation
Building, Chicago, Il.
Examination of arsphenamine and neoarsphenamine:
Associate referee: G. W. Hoover, in collaboration with C. K. Glycart, U. S.
Food and Drug Inspection Station, Transportation Build-
ing, Chicago, Ill.
Determination of alcohol in drug preparations:
Associate referee: A. G. Murray, Bureau of Chemistry, Washington, D. C.
Determination of chloroform in drug preparations:
Associate referee: A. G. Murray, Bureau of Chemistry, Washington, D. C.
Methods for the eramination of phenolphthalein:
Associale referee: S. Palkin, Bureau of Chemistry, Washington, D. C.
Analytical methods for the determination of silver in silver proteinates:
Associate referee: W. L. Mitchell, Room 1012, U. S. Appraiser’s Stores, New
York, N. Y.
Determination of camphor in pills and tablets by the alcohol distillation method:
Associate referee: G. H. Arner, Room 1012, U. 8. Appraiser’s Stores, New
Work; IN.
Determination of calomel, mercuric chloride and mercuric todide in tablets:
Associate referee: E. C. Merrill, United Drug Company, Boston, Mass.
Crude Drugs:
Associale referee: A. Viehover, Bureau of Chemistry, Washington, D. C.
Alkaloids:
Associate referee: A. R. Bliss, Emory University, Emory University, Ga.
1922| REFEREES AND ASSOCIATE REFEREES 357
Lazative and bitter tonic drugs:
Associate referee: H. C. Fuller, Institute of Industrial Research, Washington,
D.C.
Turpentine:
Associate referee: J. O. Clarke, U. S. Food and Drug Inspection Station,
U. S$. Custom-house, Savannah, Ga.
Distillation method for the estimation of santalol in santal oil:
Associate referee: C. W. Harrison, U. S. Food and Drug Inspection Station,
Park Avenue Building, Baltimore, Md.
Methods for the separation and estimation of the principal cinchona alkaloids:
Associate referee: E. O. Eaton, U. S. Food and Drug Inspection Station»
U. S. Appraiser’s Stores, San Francisco, Calif.
Methods for analysis of morphine, codeine and diacetylmorphine:
Associate referee: C. K. Glycart, U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, Il.
Analysis of acetylsalicylic acid:
Associate referee: A. E. Paul, U. S. Food and Drug Inspection Station,
Government Building, Cincinnati, Ohio.
Methods for the eraminalion of methylene blue:
Associate referee: H. O. Moraw, U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, Ill.
Methods for the eramination of procaine:
Associate referee: A. W. Hansen, U. 8. Food.and Drug Inspection Station
Transportation Building, Chicago, Il.
Methods for the eramination of pyramidon:
Associate referee: A. W. Hansen, U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, Il.
Atophan:
Associate referee: W. Rabak, U.S. Food and Drug Inspection Station, Federal
Office Building, Minneapolis, Minn.
Chloramine products:
Associate referee: W.H. Heath, Food and Drug Inspection Station, Federal
Building, Buffalo, N. Y.
Testing chemical reagents: A
Referee: G. C. Spencer, Bureau of Chemistry, Washington, D. C.
Non-alcoholic beverages:
Referee: W. W. Skinner, Bureau of Chemistry, Washington, D. C.
Eggs and egg products: (To be filled later.)
Food preservatives (saccharin):
Referee: M. G. Wolf, U.S. Food and Drug Inspection Station, U. S. Appraiser’s
Stores, New York, N. Y.
Coloring matters (oil-soluble colors):
Referee: A. L. Burns, Old Customhouse, St. Louis, Mo.
358 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Metals in foods:
Referee: W. F. Clarke, Bureau of Chemistry, Washington, D. C.
Arsenic:
Associate referee: R. M. Hann, Bureau of Chemistry, Washington, D. C.
Pectin in fruits and fruit products:
Referee: H. J. Wichmann, U.S. Food and Drug Inspection Station, Tabor Opera
House Building, Denver, Colo.
Moisture in dried fruit:
Referee: R. W. Hilts, U. S. Food and Drug Inspection Station, U. S. Appraiser’s
Stores, San Francisco, Calif.
Canned foods:
Referee: R. W. Balcom, Bureau of Chemistry, Washington, D. C.
Cereal foods:
Referee: C. H. Bailey, Agricultural Experiment Station, University Farm, St. Paul,
Minn.
Limit of accuracy of small amounts of alcohol in beers:
Referee: B. H. Hartmann, U.S. Food and Drug Inspection Station, Transportation
Building, Chicago, II.
Vinegars:
Referee: W. C. Geagley, State Dairy and Food Department, Lansing, Mich.
Flavoring ertracts:
Referee: W. W. Skinner, Bureau of Chemistry, Washington, D. C.
Meat and meat products:
Referee: C. R. Moulton, University of Missouri, Columbia, Mo.
Separation of meat proteins:
Associate referee: C. R. Moulton, University of Missouri, Columbia, Mo.
Gelatin:
Referee: C. R. Smith, Bureau of Chemistry, Washington, D. C.
Spices:
Referee: A. E. Paul, U. S. Food and Drug Inspection Station, Transportation
Building, Chicago, Ill.
Determination of shells in cacao products:
Referee: B. H. Silberberg, Bureau of Chemistry, Washington, D. C.
Methods for the examination of cacao butter:
Referee: W. F. Baughman, Bureau of Chemistry, Washington, D. C.
Coffee:
Referee: H. A. Lepper, Bureau of Chemistry, Washington, D. C.
“a
1
1922| MEMBERS AND VISITORS 359
Tea:
Referee: R. E. Andrew, Agricultural Experiment Station, New Haven, Conn.
Nitrogen in foods:
Referee: I. K. Phelps, Bureau of Chemistry, Washington, D. C.
LIST OF MEMBERS AND VISITORS PRESENT, 1921 MEETING.
Aldrich, Elizabeth, Bureau of Chemistry, Washington, D. C.
Alexander, L. M., 1703 New York Avenue, N. W., Washington, D. C.
Almy, L. H., Bureau of Chemistry, Washington, D. C.
Anderson, M. S., Bureau of Soils, Washington, D. C.
Arner, G. H., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores, New
York, N. Y.
Badger, C. H., Bureau of Chemistry, Washington, D. C.
Bailey, E. M., Agricultural Experiment Station, New Haven, Conn.
Bailey, H. S., Southern Cotton Oil Co., Savannah, Ga.
Bailey, L. H., Bureau of Chemistry, Washington, D. C.
Balch, R. T., Bureau of Chemistry, Washington, D. C.
Balcom, R. W., Bureau of Chemistry, Washington, D. C.
Baldwin, H. B., City Department of Health, Newark, N. J.
Ball, C. O., National Canners Association, 1739 H Street, N. W., Washington, D. C.
Barker, F. A., Bureau of Soils, Washington, D. C.
Barnes, J. W., Bureau of Chemistry, Washington, D. C.
Bates, Carleton, U. S. Glue Company, Milwaukee, Wis.
Bates, Frederick, Bureau of Standards, Washington, D. C.
Baughman, W. F., Bureau of Chemistry, Washington, D. C.
Beal, W. H., States Relations Service, Washington, D. C.
Bell, H. G., Canadian Fertilizer Association, Toronto, Canada.
Bentley, C. H., California Packing Corporation, San Francisco, Calif.
Beyer, G. F., Bureau of Internal Revenue, Washington, D. C.
Bidwell, G. L., Bureau of Chemistry, Washington, D. C.
Bigelow, W. D., National Canners Association, 1739 H Street, N.W., Washington, D. C.
Blaisdell, A. C., Bureau of Internal Revenue, Washington, D. C.
Bohart, G. S., National Canners Association, 1739 H Street, N.W., Washington, D. C.
Bopst, L. E., Bureau of Chemistry, Washington, D. C.
Bost, W. D., Orange Crush Company, Chicago, Ill.
Bostwick, E. P., National Canners Association, 1739 H Street, N. W., Washington,
1 DK OF
Bowling, J. D., Bureau of Chemistry, Washington, D. C.
Boyle, Martin, Bureau of Chemistry, Washington, D. C.
Brackett, R. N., Clemson Agricultural College, Clemson College, S. C.
Bradbury, C. M., State Department of Agriculture and Immigration, Richmond, Va.
Bradley, L. W., Department of Agriculture, Atlanta, Ga.
Bradshaw, M. A., Bureau of Internal Revenue, Washington, D. C.
Breckenridge, J. E., American Agricultural Chemical Co., New York, N. Y.
Brewer, W. O., Calco Chemical Company, Bound Brook, N. J.
Broughton, L. B., University of Maryland, College Park, Md.
Brown, B. E., Bureau of Plant Industry, Washington, D. C.
Buchanan, Miss Ruth, Bureau of Chemistry, Washington, D. C.
Bumgamer, A. J., Uniontown, Pa.
Burritt, Loren, Treasury Department, Washington, D. C.
Burroughs, L. C., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
-
360 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Capen, Miss R. G., Bureau of Chemistry, Washington, D. C.
Carpenter, F. B., Virginia~-Carolina Chemical Co., Richmond, Va.
Casey, F. W., Bureau of Internal Revenue, Washington, D. C.
Cathcart, P. H., Ballston, Va.
Charlton, R. C., 211 E. North Avenue, Baltimore, Md.
Chesnut, V. K., Bureau of Chemistry, Washington, D. C.
Clark, A. W., Agricultural Experiment Station, Geneva, N. Y.
Clarke, J. O., U. S. Custom-house, Bay and Bull Streets, Savannah, Ga.
Clarke, W. F., Bureau of Chemistry, Washington, D. C.
Clemens, Miss A. M., Bureau of Chemistry, Washington, D. C.
Clevenger, J. F., Bureau of Chemistry, Washington, D. C.
Coe, M. R., Bureau of Chemistry, Washington, D. C.
Coleman, D. A., Bureau of Markets, Washington, D. C.
Collins, Miss E. W., Federal Relations Bureau, Inc., 1310 F Street, N. W., Washing-
ton, D. C.
Collins, W. D., U. S. Geological Survey, Washington, D. C.
Conrad, C. M., University of Maryland, College Park, Md.
Craig, R. S., City Health Department, Baltimore, Md.
Crawford, C. W., Bureau of Chemistry, Washington, D. C.
Cross, L. J., Cornell University, Ithaca, N. Y.
Custis, H. H., Bureau of Animal Industry, Washington, D. C.
Dachnowski, A. P., Bureau of Plant Industry, Washington, D. C.
Daish, Miss W. M., Department of Agriculture, Washington, D. C.
Dallas, Miss M. L., Bureau of Chemistry, Washington, D. C.
Darkis, F. R., University of Maryland, College Park, Md.
Davidson, J., Bureau of Chemistry, Washington, D. C.
Davis, Miss C. M., Bureau of Chemistry, Washington, D. C.
Davis, R. O. E., Bureau of Soils, Washington, D. C.
Dawson, P. R., Bureau of Plant Industry, Washington, D. C.
Deemer, R. B., Bureau of Plant Industry, Washington, D. C.
DeTurk, E. E., 707 W. Green Street, Urbana, Ill.
Deyo, Mrs. J. P., Bureau of Chemistry, Washington, D. C.
Deysher, E. F., Bureau of Animal Industry, Washington, D. C.
Dobson, C. R., 630 Keefer Place, N. W., Washington, D. C.
Donaldson, E. C., University of Maryland, College Park, Md.
Donk, P. J., Stokeley Brothers & Co., Newport, Tenn.
Doolittle, R. E., Transportation Building, Chicago, Ill.
Doran, J. M., Bureau of Internal Revenue, Washington, D. C.
Dubois, W. L., Eline’s, Incorporated, Milwaukee, Wis.
DuMez, A. G., Hygienic Laboratory, Washington, D. C.
Dunbar, P. B., Bureau of Chemistry, Washington, D. C.
Dunlap, F. L., 1457 Monadnock Block, Chicago, Ill.
Durgin, C. B., Bureau of Soils, Washington, D. C.
Duvall, Miss Louise, Bureau of Chemistry, Washington, D. C.
Easterwood, H. W., Bureau of Soils, Washington, D. C.
Eastman, A. S., Caleo Chemical Company, Bound Brook, N. J.
Eaton, E. O., U. S. Appraiser’s Stores, Sansome and Washington Streets, San Fran-
cisco, Calif.
Edmonds, H. G., 1026 Newton Street, Brookland, D. C.
Edwards, P. W., Bureau of Chemistry, Washington, D. C.
Elbon, F. L., Musher and Company, Baltimore, Md.
1922] MEMBERS AND VISITORS 36]
Ellett, W. B., Blacksburg, Va.
Ellis, J. F., Bureau of Chemistry, Washington, D. C.
Ellis, N. R., Bureau of Animal Industry, Washington, D. C.
Elvoye, Elias, U. S. Public Health Service, Washington, D. C.
Emery, W. O., Bureau of Chemistry, Washington, D. C.
Emmons, F. W., Washburn-Crosby Company, Minneapolis, Minn,
Evenson, O. L., Bureau of Chemistry, Washington, D.C.
Ferguson, J. J., Swift and Company, Chicago, III.
Ferris, L. W., Bureau of Chemistry, Washington, D. C.
Field, Elmer, Bureau of Chemistry, Washington, D. C.
Finks, A. J., Bureau of Chemistry, Washington, D. C.
Fitzgerald, F. F., American Can Company, Maywood, Il.
Flenner, A. L., University of Maryland, College Park, Md.
Fletcher, C. C., Bureau of Soils, Washington, D. C.
Forbes, D. R., National Preservers Association, 1310 F Street, N. W., Washington, D. C.
Foster, Miss M. D., U. S. Geological Survey, Washington, D. C.
Fraps, G. S., Agricultural Experiment Station, College Station, Tex.
Frear, William, Agricultural Experiment Station, State College, Pa.
French, D. M., 115 N. Columbus Street, Alexandria, Va.
Frere, F. J., Bureau of Standards, Washington, D. C.
Frisbie, W. S., Bureau of Foods and Drugs, Lincoln, Neb.
Fuller, F. D., Agricultural Experiment Station, College Station, Texas.
Fuller, H. C., Institute of Industrial Research, Washington, D. C.
Gaines, R. H., New York Board of Water Supply,Municipal Building, New York, N. Y.
Gardiner, R. F., Bureau of Soils, Washington, D. C.
Gascoyne, W. J., 27 South Gay Street, Baltimore, Md.
Geagley, W. C., State Food and Drug Department, Lansing, Mich.
Gebhart, A. I., Bureau of Internal Revenue, Washington, D. C.
Gensler, H. E., Department of Agriculture, Harrisburg, Pa.
Gersdorff, C. E. F., Bureau of Chemistry, Washington, D. C.
Gilbert, H. D., University of Maryland, College Park, Md.
Gill, P. L., Bureau of Soils, Washington, D. C.
Gilmore, B. H., Bureau of Internal Revenue, Washington, D. C.
Glycart, C. K., U. S. Food and Drug Inspection Station, Transportation Building,
Chicago, Ill.
Goodrich, C. E., Bureau of Chemistry, Washington, D. C.
Gordon, J. B., Munsey Building, Washington, D. C.
Gordon, N. E., Agricultural Experiment Station, College Park, Md.
Gore, H. C., Bureau of Chemistry, Washington, D. C.
Graham, J. J. T., Bureau of Chemistry, Washington, D. €.
Gray, M. A., 1200 Metropolitan Life Building, Minneapolis, Minn.
Grayson, Miss M. C., Bureau of Chemistry, Washington, D. C.
Grewe, Miss Emily, Federal Milling and Elevator Company, Lockport, N. Y.
Griffin, E. L., Bureau of Chemistry, Washington, D. C.
Grille, G. A. Jr., Eimer & Amend, New York, N. Y.
Gross, C. R., Bureau of Chemistry, Washington, D. C.
Grotlisch, V. E., Bureau of Chemistry, Washington, D. C.
Haller, H. L., Bureau of Chemistry, Washington, D. C.
Halvorson, H. A., State Dairy and Food Commission, St. Paul, Minn.
Hand, W. F., Agricultural College, Agricultural College, Miss.
362 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Hanks, A. K., Spencer Lens Company, Buffalo, N. Y.
Hann, R. M., Bureau of Chemistry, Washington, D. C.
Hanson, H. H., State Board of Health, Dover, Del.
Harcourt, R., Ontario Agricultural College, Guelph, Ontario, Canada.
Harris, J. R., Tennessee Coal, Iron and Railroad Company, Birmingham, Ala.
Harrison, C. W., U. S. Food and Drug Inspection Station, Park Avenue Building,
Baltimore, Md.
Hart, B. R., Department of Commerce, Washington, D. C.
Hart, Leslie, Bureau of Chemistry, Washington, D. C.
Hartman, Miss M. E., Bureau of Chemistry, Washington, D. C.
Haskins, H. D., Agricultural Experiment Station, Amherst, Mass.
Hayes, J. F., 8 Donaldson Street, Cherrydale, Va.
Haywood, J. K., Bureau of Chemistry, Washington, D. C.
Hazen, William, Bureau of Soils, Washington, D. C.
Himmler, L. W., Bureau of Animal Industry, Washington, D. C.
Hodgins, R. J., University of Maryland, College Park, Md.
Holm, G. E., Bureau of Animal Industry, Washington, D. C.
Holman, H. P., Bureau of Chemistry, Washington, D. C.
Holmes, R. S., Bureau of Soils, Washington, D. C.
Hoover, G. W., U. S. Food and Drug Inspection Station, Transportation Building,
Chicago, Ill.
Hortvet, Julius, State Dairy and Food Commission, St. Paul, Minn.
Houghton, H. W., Hygienic Laboratory, Washington, D. C.
Howard, B. J., Bureau of Chemistry, Washington, D. C.
Howard, C.S., U. S. Geological Survey, Washington, D. C.
Howe, H. E., Otis Building, Washington, D. C.
Hubbard, W. S., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores,
New York, N. Y.
Hurd, W. D., 819 Southern Building, Washington, D. C.
Hurst, L. A., Bureau of Plant Industry, Washington, D. C.
Huston, H. A., 42 Broadway, New York, N. Y.
Irwin, W. H., Swift and Company, Chicago, Ill.
Jackson, R. F., Bureau of Standards, Washington, D. C.
Jacob, K. D., 1310 Irving Street, N. W., Washington, D. C.
Jacobs, B. R., 1731 H Street, N. W., Washington, D. C.,
Jamieson, G. S., Bureau of Chemistry, Washington, D. C.
Jarrell, T. D., Bureau of Chemistry, Washington, D. C.
Jenkins, L. J., Bureau of Chemistry, Washington, D. C.
Jinkins, R., Bureau of Chemistry, Washington, D. C.
Johnson, J. M., Hygienic Laboratory, Washington, D. C.
Jones, D. B., Bureau of Chemistry, Washington, D. C.
Jones, R. M., Bureau of Soils, Washington, D. C.
Kebler, L. F., Bureau of Chemistry, Washington, D. C. i
Keenan, G. L., Bureau of Chemistry, Washington, D.C. ~
Keener, O. S., Bureau of Chemistry, Washington, D. C.
Keister, J. T., Bureau of Chemistry, Washington, D. C.
Kellogg, J. W., State Department of Agriculture, Harrisburg, Pa.
Kerr, R. H., Bureau of Animal Industry, Washington, D. C.
Kimberly, C. H., Philadelphia, Pa.
Kohman, E. F., National Canners Association, 1739 H Street, N. W., Washington,
DAG:
1922] MEMBERS AND VISITORS 363
Koser, S. A., Bureau of Chemistry, Washington, D. C.
Kunke, W. F., Bureau of Chemistry, Washington, D. C.
Langenbeck, Karl, 1625 Hobart Street, Washington, D.C.
Lapp, Miss M. E., Bureau of Chemistry, Washington, D. C.
Larson, C. W., Bureau of Animal Industry, Washington, D. C.
Lathrop, E. C., E. I. DuPont de Nemours, Wilmington, Del.
Law, T. C., Law and Company, Atlanta, Ga.
LeFevre, Edwin, Bureau of Chemistry, Washington, D. C.
Leighty, W. R., Bureau of Plant Industry, Washington, D. C.
Lepper, H. A., Bureau of Chemistry, Washington, D. C.
Lichtenwalner, D. O., University of Maryland, College Park, Md.
Linden, B. A., Bureau of Chemistry, Washington, D. C.
Linder, W. V., Bureau of Internal Revenue, Washington, D. C.
Lodge, F. S., Armour Fertilizer Works, Chicago, Ill.
Longenecker, L. S., Elizabethtown, Pa.
Loomis, H. M., National Canners Association, 1739 H Street, N. W., Washington, D. C.
Lourie, H. L., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores, New
Work, N> Y:
Lythgoe, H. C., State Department of Public Health, Boston, Mass.
MaclIntire, W. H., Agricultural Experiment Station, Knoxville, Tenn.
Magruder, E. W., F. S. Royster Guano Company, Norfolk, Va.
Mains, G. H., Bureau of Chemistry, Washington, D. C.
Manross, Miss L. M., Bureau of Chemistry, Washington, D. C.
Marshall, W. K., Bureau of Markets, Washington, D. C.
Mather, William, Agricultural Experiment Station, College Park, Md.
Mathewson, W. E., Bureau of Chemistry, Washington, D.C.
McCall, A. G., Agricultural Experiment Station, College Park, Md.
McDonnell, C. C., Bureau of Chemistry, Washington, D. C.
McDonnell, H. B., Agricultural Experiment Station, College Park, Md.
McGill, A., Department of Health, Ottawa, Canada.
MeNair, J. B., P.O. Box 2, Pennsylvania Avenue Station, Washington, D. C.
Mehring, A. L., Bureau of Animal Industry, Washington, D. C.
Mehurin, R. M., Bureau of Animal Industry, Washington, D. C.
Menge, G. A., 4598 Oakenwald Avenue, Chicago, Il.
Middleton, H. E., Bureau of Soils, Washington, D. C.
Miller, E. R., Bureau of Chemistry, Washington, D. C.
Miller, G. E., Bureau of Chemistry, Washington, D. C.
Mitchell, A. S., Bureau of Chemistry, Washington, D. C.
Mitchell, G. F., Bureau of Chemistry, Washington, D.C. .
Mix, Miss A. E., Bureau of Chemistry, Washington, D. C.
Moore, Paul, National Research Council, Washington, D. C.
Moore, Mrs. U. S., Bureau of Chemistry, Washington, D. C.
Morawski, A. L., 442 Massachussetts Avenue, N. W., Washington, D. C.
Morton, J. K., Bureau of Chemistry, Washington, D. C.
Mottern, A. J., Bureau of Internal Revenue, Washington, D. C.
Moulton, C. R., University of Missouri, Columbia, Mo.
Moulton, S. C., Health Department, Washington, D. C.
Munch, J. C., Bureau of Chemistry, Washington, D. C.
Murray, A. G., Bureau of Chemistry, Washington, D. C.
Nelson, E. K., Bureau of Chemistry, Washington, D. C.
Noel, W. A., Bureau of Chemistry, Washington, D. C.
364 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Northern, A. J., University of Maryland, College Park, Md.
Offutt, Miss M. L., Bureau of Chemistry, Washington, D. C.
Owen, W. O. C., Musher and Company, Baltimore, Md.
Pack, W. D., Department of Health, Cleveland, Ohio.
Palkin, S., Bureau of Chemistry, Washington, D. C.
Palmore, J. I., Bureau of Chemistry, Washington, D. C.
Pappe, T. F., Bureau of Chemistry, Washington, D. C.
Parkins, J. H., F. S. Royster Guano Company, Norfolk, Va.
Parkinson, Miss N. A., Bureau of Chemistry, Washington, D. C.
Patterson, H. J., Agricultural Experiment Station, College Park, Md.
Perrine, Norman, Federal Horticultural Board, Washington, D. C.
Phelps, I. K., Bureau of Chemistry, Washington, D. C.
Phillips, S., Bureau of Chemistry, Washington, D. C.
Pingree, M. H., American Agricultural Chemical Company, 2343 South Clinton Street,
Baltimore, Md.
Power, F. B., Bureau of Chemistry, Washington, D. C.
Powick, W. C., Bureau of Animal Industry, Washington, D. C.
Price, D. J., Bureau of Chemistry, Washington, D. C.
Price, T. M., City Health Department, Washington, D. C.
Proffitt, M. J., Bureau of Standards, Washington, D. C.
Proulx, E. G., Agricultural Experiment Station, La Fayette, Ind.
Rains, Miss Opal, Bureau of Chemistry, Washington, D. C.
Randall, W. W., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Read, Miss E. A., Bureau of Chemistry, Washington, D. C.
Redfield, H. W., U. S. Food and Drug Inspection Station, U. S. Appraiser’s Stores,
New York, N. Y.
Reed, J. B., Bureau of Chemistry, Washington, D. C.
Reese, H. C., Bureau of Chemistry, Washington, D. C.
Reed, J. O., Bureau of Chemistry, Washington, D. C.
Reindollar, W. F., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
Reinmuth, O., University of Maryland, College Park, Md.
Remsburg, C. G., Hygienic Laboratory, Washington, D. C.
Riffenburg, H. B., U. S. Geological Survey, Washington, D. C.
Riley, J. G., Bureau of Internal Revenue, Washington, D. C.
Roark, R. C., General Chemical Company, Baltimore, Md.
Roberts, C. C., Arthur H. Thomas Company, Philadelphia, Pa.
Robey, V. C. K., Bureau of Internal Revenue, Washington, D. C.
Robinson, C. H., Central Experimental Farm, Ottawa, Canada.
Roeg, L. M., Musher and Company, Baltimore, Md.
Rose, R. E., Department of Agriculture, Tallahassee, Fla.
Ross, B. B., Polytechnic Institute, Auburn, Ala.
Ross, W. H., Bureau of Soils, Washington, D. C.
Russell, G. A., Bureau of Plant Industry, Washington, D. C.
Sale, J. W., Bureau of Chemistry, Washington, D. C.
Scales, F. M., Bureau of Plant Industry, Washington, D. C.
Schench, J. D., University of Maryland, College Park, Md.
Schertz, F. M., Bureau of Plant Industry, Washington, D. C.
Schreiner, Oswald, Bureau of Plant Industry, Washington, D. C.
Schulze, W. H., State Department of Health, 16 W. Saratoga Street, Baltimore, Md.
1922] MEMBERS AND VISITORS 365
Schwartze, E. W., Bureau of Chemistry, Washington, D. C.
Scott, Miss D. B., Bureau of Chemistry, Washington, D. C.
Scott, R. D., Department of Health, Columbus, Ohio.
Sebring, B. W., Department of Agriculture, Columbus, Ohio.
Seidell, Atherton, Hygienic Laboratory, Washington, D. C.
Senseman, C. E., Bureau of Chemistry, Washington, D. C.
Sherwood, S. F., Bureau of Plant Industry, Washington, D. C.
Shrader, J. H., Health Department, Baltimore, Md.
Shulenberger, F. W., Eimer & Amend, New York, N. Y.
Sievers, A. F., Bureau of Plant Industry, Washington, D. C.
Silberberg, Miss B. H., Bureau of Chemistry, Washington, D. C.
Skinner, J. J., Department of Agriculture, Washington, D. C.
Skinner, Miss L. A., Bureau of Chemistry, Washington, D. C.
Skinner, W. W., Bureau of Chemistry, Washington, D. C.
Smith, A. M., Agricultural Experiment Station, College Park, Md.
Smith, J. G., Bureau of Soils, Washington, D. C.
Smith, Miss J. K., Bureau of Chemistry, Washington, D. C.
Smith, Miss S. L., States Relations Service, Washington, D.C.
Smith, W. C., Bureau of Chemistry, Washington, D. C.
Smither, F. W., Bureau of Standards, Washington, D. C.
Snyder, C. F., Bureau of Standards, Washington, D. C.
Snyder, E. F., Bureau of Plant Industry, Washington, D. C.
Sorber, D. G., Bureau of Animal Industry, Washington, D. C.
Spear, A. A., Bureau of Internal Revenue, Washington, D. C.
Spencer, G. C., Bureau of Chemistry, Washington, D. C.
Starkey, E. B., University of Maryland, College Park, Md.
Stevenson, A. E., National Canners Association, 1739 H Street, N. W., Washington,
DSC:
Strowd, W. H., State Department of Agriculture, Madison, Wis.
Sullivan, M. X., Hygienic Laboratory, Washington, D.C.
Swicker, V. C., 1827 Monroe Street, Washington, D. C.
Taylor, A. E., Bureau of Chemistry, Washington, D. C.
Taylor, J. N., Bureau of Animal Industry, Washington, D. C.
Thatcher, A. S., Loose-Wiles Biscuit Company, Long Island City, N. Y.
Thom, Charles, Bureau of Chemistry, Washington, D. C.
Thomson, E. C., The Borden Company, 350 Madison Avenue, New York, N. Y.
Thompson, H. L., Empire Laboratory Supply Company, 218 East 37th Street, New
York, N. Y.
Thornton, E. W., 212 William Street, East Orange, N. J.
Thornton, Mrs. E. W., 212 William Street, East Orange, N. J.
Toll, J. D., 1010 Arch Street, Philadelphia, Pa. .
Turner, W. A., 1774 U Street, N. W., Washington, D. C.
Ullrich, Miss J. R., 23 Beaver Street, New York, N. Y.
Valaer, Peter, Jr., Bureau of Internal Revenue, Washington, D. C.
Van Wormer, L. H., Riverdale, Md.
Veitch, F. P., Bureau of Chemistry, Washington, D. C.
Viehoever, Arno, Bureau of Chemistry, Washington, D. C.
Vollertsen, J. J., Morris and Company, Chicago, Ill.
Waggaman, W. H., Bureau of Soils, Washington, D. C.
Walker, P. H., Bureau of Standards, Washington, D. C.
366 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Wallace, H. C., Des Moines, Iowa.
Walsh, D. M., Bureau of Chemistry, Washington, D. C.
Walton, C. F., Jr., Bureau of Chemistry, Washington, D. C.
Walton, G. P., Bureau of Chemistry, Washington, D. C.
Waterman, H. C., Bureau of Chemistry, Washington, D. C.
Watkins, H. C., 504 Lackawanna Avenue, Scranton, Pa.
Weber, F. C., Bureau of Chemistry, Washington, D. C.
Weems, J. B., State Department of Agriculture, Richmond, Va.
Weigel, C. A., Bureau of Entomology, Washington, D. C.
Weir, W. W., 3918 McKinley Street, N. W., Washington, D. C.
Whitney, C. F., Burlington, Vt.
Wilcox, E. L., Bureau of Internal Revenue, Washington, D. C.
Wiley, H. W., 1120 Woodward Building, Washington, D. C.
Wiley, R. C., Agricultural Experiment Station, College Park, Md.
Wiley, S. W., Wiley and Company, Inc., Calvert and Read Streets, Baltimore, Md.
Williams, C. C., National Canners Association, 1739 H Street, N. W., Washington,
DG:
Wilson, J. B., Bureau of Chemistry, Washington, D. C.
Wilson, S. H., State Department of Agriculture, Atlanta, Ga.
Wilson, S. M., Baugh & Sons Co., Baltimore, Md.
Winant, H. B., Agricultural Experiment Station, College Park, Md.
Wooton, Paul, Colorado Building, Washington, D. C.
Wright, C. D., Bureau of Chemistry, Washington, D. C.
Young, H. D., Bureau of Chemistry, Washington, D. C.
Zoller, H. F., Nizer Laboratories Company, Detroit, Mich.
PRESIDENT’S ADDRESS.
RECENT TENDENCIES OF RESEARCHES ON THE PHOTOSYNTHETIC
PROCESSES OF PLANTS.
By W. F. Hanp (Mississippi Agricultural and Mechanical College,
Agricultural College, Miss.), President.
Throughout all the years of its life, this organization has held closely
to its original purpose. The steady expansion of its activities is con-
vincing evidence of a proper interpretation of its mission, and even
now its interests are so varied and far-reaching that we fear that we
must soon look forward to the time when we will be compelled to sacri-
fice something of solidarity and good fellowship by the adoption of the
group system in conducting our annual convocations. But however
that may be, we are certain to become increasingly useful. From our
constant excursions into the unknown, we have brought back during
the many years of our history much knowledge useful for the daily
guidance and essential for the future development of the industrial and
1 Presented Tuesday morning, October 25, 1921, as special order of business for 11 o'clock.
1922] HAND: PRESIDENT’S ADDRESS 367
governmental activities with which we are closely related. In this
respect we may believe that we have been particularly favored by
fortune; for to the mere pleasure arising from co-operative study there
can be added tthe satisfying assurance that our labors have been dis-
tinctly helpful to our day and generation.
In earlier times especially there was a pressing need for a quick turn-
over. The necessity for close association and concerted attack on
important problems drew forth all possible energy. It may be that we
are destined to become accustomed to mass production in scientific
research in general as a result of unified administration and specializa-
tion. If that be true, we shall not be wholly unprepared for the new
order.
But while we are devoting the closest attention to the advancement
of the work lying nearest at hand, the ideal of immediate effective
service will not be pursued with so much zeal that no time and no interest
will remain for reflection upon great and even majestic problems in our
field, the final solution of which will demand the life-labor of generations,
perhaps, of able, unselfish men. JI have believed it not inappropriate,
therefore, to endeavor to direct your attention for a short while to
some of the aspects of a distinctly fundamental biochemical problem.
From the earliest times men haye been puzzled by the varied and
manifold phenomena of life. If even the processes of the simpler plant
forms, which are indefinitely less complex than those of animals, could
be wholly elucidated, a yearning of many centuries would be satisfied.
We are slowly, but, let us hope, none the less surely, approaching the
day of that realization. An imposing collection of facts has become
available, and we take encouragement from the belief that the greatest
difficulties yet remaining shall not overwhelm us.
More than two hundred years ago it was known that leaves were in
some way connected with the elaboration of tissue, but Priestley, in 1772,
was the first to show that plants restored respired air. He was re-
warded with a medal in recognition of the importance of his discovery,
but his investigations were interrupted somewhat by the publication of
the experimental researches of the Dutch physician, Ingenhousz, who
received no thanks from Priestley for this unsolicited assistance. Ingen-
housz established beyond doubt that leaves evolve oxygen in light and
spoil air in darkness.
But to de Saussure belongs the credit of first demonstrating that
plants may take the carbon required for their development from the
atmosphere. Liebig was not slow in appreciating the fundamental
nature of the discoveries resulting from de Saussure’s studies, but he
was not always wholly clear with regard to some of the aspects of
plant respiration. Boussingault, having much better apparatus avail-
able, fully confirmed de Saussure’s work and pointed out in a very con-
368 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
vincing way that the synthesis of sugar was, after all, the goal of
carbon dioxide assimilation.
Many men whose names are eminent in our literature have made
contributions to the still unrevealed method of the primary synthetic
processes occurring in plant leaves. Accounts of the historical develop-
ment of the subject are easily available. The effort that has been
expended is truly prodigious; it is surely deserving of a better outcome.
Numerous vexing questions have arisen to beset the investigator. In
the first place, the minute amount of carbon dioxide in the atmosphere,
the small total area of the openings in leaves and the large amount of
carbon in plants have made the rapid growth of vegetation appear not
a little mysterious to those giving no special study to the subject. A
square centimeter of leaf surface may take up during a single hour an
amount of carbon dioxide equivalent to that in a column of air of the
same cross section and more than one hundred centimeters long. The
avidity with which leaves take in COsz is truly surprising. Liebig com-
pared them in this respect to a paste of calcium hydroxide, and Brown?
has shown that the analogy is by no means unjustified, because he found
that a strong solution of caustic alkali, contained in a special apparatus
providing for constant renewal, could absorb 0.17 cc. of CO» an hour for
each square centimeter. A catalpa leaf has been observed to take up
CO, more than half as rapidly as that. Brown has pointed out also
the true explanation of the way in which so large an amount of CO2 may
pass into the stomata. Computations show that only the slightest
difference in the partial pressure of the gas within and without the
leaf is quite sufficient to account for the rapid exchange required in the
absorption.
The literature has accumulated an impressive array of hypotheses
and theories with reference to the mechanism of carbon fixation. A
few of these are little more than improbable suggestions resting on no
experimental work; others derive error from faulty experiment or from
improper deductions, and the question is still awaiting an answer, definite
and direct. There is no occasion to exhaust your patience by even a
brief discussion of much of the important work that has been accom-
plished in this field. The older researches, however, may not be lightly
dismissed, because these have made the way less difficult for the more
careful studies of recent years.
One finds almost everywhere in the literature reference to the historic
suggestion of A. Baeyer? that formaldehyde is an intermediate product
of CO, reduction in the leaf. Carbohydrates may result through aldol
condensations and by the loss of water from the condensed nuclei. The
1 Proc. Roy. Institution (Great Britain), 1901, 16: 547.
2 Ber. Chem. Ges., 1870, 3: 63.
1922] HAND: PRESIDENT’S ADDRESS 369
theory appeared to be a very happy one, and almost no end of labor has
been put forth in unsuccessful endeavors to fully confirm it. Failing in
this, and being unable to ascertain the relation of chlorophyll to the
process, researchers have looked in other directions for theories; and
perhaps it was in despair that some of the rather unique hypotheses
which have come forth have had their birth.
Wislicenus! has recently carried out the reduction of carbonic acid to
formic acid by hydrogen peroxide and also by the electrolysis of a solu-
tion of potassium bicarbonate. He has sought to build a theory of
carbon assimilation on the basis of these results. He suggests that
there is a sufficient amount of H.O, in the air to carry out the process
in nature. The formic acid produced in the reduction (the reaction
requires no energy absorption) is subsequently converted to formalde-
hyde, the energy increment being received through light absorption by
aid of chlorophyll catalysis.
The explanation of the reduction of HCO; by H.O2 to formic acid
requires a postulate with reference to the structure of the anion of the
acid. It is assumed that an aqueous solution of it must contain some
concentration of percarbonic acid in order that reduction may be
accomplished by the peroxide. The reaction follows:
H-O-C-O-H2 H-C-0-0-H2 Ht H-C-0-07
fe) ° fo)
H-O-O-H + H-C-O-0-H —> H-O-H+02 + H-C-O-H
1°} fe)
During electrolysis of a solution of KHCOs, the H:Os, formed by dis-
charge of two OH ions, may react with the discharged anion of peroxide
structure, reduction then being accomplished by splitting out of oxygen.
Omitting the cations, the anodic reduction may be expressed by
H-€-0-0 H-O0-O-H
fe) + — 2H,0+20,+2H-C-O-H
H=C-0-0 H-0-0-H fo)
fo) or
eae Lr +O. + H-C-O-H
S=c~y + aE — H2,0+0O2 S
In the leaves of plants the formic acid is reduced to formaldehyde by
the aid of chlorophyll and through the absorption of the necessary
energy from light.
In this cycle of changes, the volume of CO2 converted to formic acid
is identical with that of the oxygen evolved. This ratio corresponds
with the best observations that have been made with growing leaves.
1 Ber. Chem. Ges., 1918, 51: 942.
370 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
As unusual as the peroxide structure of carbonic acid may appear,
the conception is not without its supporters. Woker! also believes it
probable that the reactivity of CO» in the plant world is due to its
ability to produce, in some measure at least, unstable isomers through
combination with water, in accordance with the following representa-
tions:
80
H-
cOz— coe 20, “No
RED an H-O- C-O-O-H I
‘XN
The unstable peroxide, II, would tend to lose oxygen, leaving a
methylene radical, isomeric with formaldehyde, and conceivably prone
to enter into numerous condensations resulting in the production of such
bodies as dihydroxyacetone, glucose, furfural, and so forth.
Woker looks upon chlorophyll as taking possibly the role of a sensi-
bilizer of the peroxide isomerization of carbonic acid, and also as an
intermediate catalyzer of the condensation phases of the subsequent
reactions. The optical activity of chlorophyll would permit the pro-
duction of optically active compounds.
Without attempting to detract in the least from the plausibility of
Woker’s cycle, it may be added that a heavy burden of proof is again
placed upon the chlorophyll molecule. This is not unusual in researches
in this field. Charges and countercharges have been brought against
the green coloring matter of the plants. Too sensitive not to feel the
injury of unjust accusation, but suffering in silence, it is truly a stoic
in the molecular world.
No lesser authorities than Willstitter and Stoll? also bring forth a
theory of photosynthetic action involving a shifting of valence in the
carbonic acid molecule as a result of the absorption of radiant energy.
According to this view, carbonic acid may pass over to formylhydrogen
peroxide, or to performic acid. The rearrangement of the latter to car-
bonic acid is already well known. It appears possible that a derivative
of formaldehyde peroxide may also have a share in the scheme of assimi-
lation which the authors suggest, and this conception would carry still
greater force but for the fact that the compound itself remains undis-
covered.
Willstatter and Stoll show that aqueous colloidal solutions of chloro-
phyll (but not dispersions in organic liquids) take up COz2 from the air.
Such solutions are capable of reacting with two molecules of H2COs,
the reaction being complete when Mg(HCOs)2 is split off. In the
1 Arch. ges. Physiol., 1919, 176: 11; Chem. Abstr., 1920, 14: 963.
2 Ber. Chem. Ges., 1917, 50: 1791.
1922| HAND: PRESIDENT’S ADDRESS 371
course of these changes an intermediate compound of chlorophyll and
H.CO; may be produced, and this is dissociable:
i uN u ‘ ul ut
Cc
A a Pe Oe ae
=N ne is =N Ne wn
N ox Prac cO2 Ye 0 N N—Mg-o
= = —Mg-0-C-0-H
rs AW IE
’ u ul ' u u
INTERMEDIATE COMPOUND
If the intermediate body is imagined to rearrange into the isomeric
peroxide structure and then to lose oxygen, it would be natural to expect
the production of a chlorophyll compound of formic acid:
carrey! c-
ao. we
Lo
AN <7 LAS Mg-O- ec a
Pee ae [SOMERIDE
' u “
cS (<= (SS
b =— ie \ 7 in
=n Za ‘d Re S Hig L i
S are was gi
{ ca " =4
Ne ee ose De <=
noe sraicrare
The formate is incapable of losing oxygen, but this does not apply
to its corresponding peroxide isomeride, which parts with a half molecule,
leaving a molecule of formaldehyde and reproducing the original chloro-
phyll structure:
Thus all of the CO: is accounted for, an equivalent volume of oxygen
is liberated, and the often-mentioned progenitor of the carbohydrates,
formaldehyde, is obtained.
372 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
A somewhat similar interpretation of the mechanism of carbon assimi-
lation has been brought out recently by Rouge! who holds the opinion
that glycolaldehyde is the first product produced in the assimilatory
process. He shows that minute amounts of the aldehyde may be
detected by p-nitrophenylhydrazine, and succeeds in making quantita-
tive determinations by weighing the hydrazone. It is presumed that
other aldehydes that may be present were not included in his qualita-
tive tests and quantitative determinations.
Through a modification of the theory of Willstaétter and Stoll, it is
possible to account for the formation of the glycolaldehyde, the presence
of which in plants Rouge believes his experiments to have demonstrated.
The changes involved may be expressed as follows:
=N =N-H =N-H H
Mg + CO, +H = Soa
aye g eee =N-Mg-0-C-O-H =N-Mg-0-€<?
°
crerrere- +
H
sN——Mg=0-¢-—=—¢_O-Mg— ine
Lal N=
-AJ- as ’
Se i ‘et ee N= _+0,+ H-C—C¢-H+2 Mg<
= g Cae aOiMggN= é 6 =
The co-operation of some unknown catalase is thought to be essential
to a realization of these reactions. Perhaps there is little cause to
question the plausibility of this view of carbohydrate production, but
certainly there is reason to hope that experimental evidence will con-
tinue to accumulate until we may judge its merits more clearly than we
are permitted to do to-day.
The desperate condition in which we find ourselves with reference
to the forces and materials employed in the tiny laboratories of leaves is
indicated by the bold guesses scattered throughout the voluminous
literature of this very old subject. Nor are these suggestions, un-
supported by experiments as many of them are, entirely without value.
We have not found the way, but we can search the better for it with
the aid of the light we already possess. The cost of failures and of
trials will not remain long in memory when we are finally rewarded by
successful accomplishment.
1 Schweiz. Apoth.—Zlg., 1921, 59: 157, 175; Chem. Abstr., 1921, 15: 2294.
~ ond by further loss of oxygen:'
1922} HAND: PRESIDENT’S ADDRESS 373
Finding that the diketone, benzil and hydrogen react in light to form
benzoin, Kogel' has thought that the reaction under these conditions
might form a pattern for photosynthetic assimilation. He conceives
the possible formation of an intermediate dihydroxyethylene dioxide
through the reaction of carbon dioxide and water, and the subsequent
breaking up of this body into formaldehyde and oxygen, or the pro-
duction from it of formic or oxalic acid. In a similar way glyceralde-
hyde and oxygen may be a result of interaction of COzand H.O under
external influences. The compounds so produced are suited to carbo-
hydrate synthesis:
O=C=O H-O-H O-C-O-H
7 2 See a ey
O=C=O H-O-H H-O-C-O
OR H
O=C=0O H-O-H HoCeO-t
O=C=0 tiN-O-)-— »H-C-O-H +3 Os
eG=C=0 H-O-H H-C=0
Investigators in general have become thoroughly indoctrinated with
the chlorophyll theory; it is regarded as the material agent mostly
responsible for the strange transformations which occur in the building
up of organic matter. Preponderating evidence, direct and indirect,
appears to favor this view, but it can scarcely be said that its experi-
mental demonstration has been accomplished.
Moore?, whose excellent work will be praised by all students of carbon
assimilation, points out the absence of proof that the colorless parts of
the chloroplasts may not be the seat of the synthetic activities. Chloro-
phyll cannot be developed in absence of iron, though the green itself is
free of iron. Inorganic iron in crystalloidal or colloidal states is a
constant component of the colorless parts of chloroplasts; and, there-
fore, it appears that chlorophyll is itself a photosynthetic product
formed through the agency of the iron-bearing parts of the leaf structure.
It is Moore’s opinion that the parts containing iron and the chlorophyll
produced by them become associated in photosynthesis and form a
complete mechanism for the energy transformations of plant growth.
From his study of the photodxidation of chlorophyll and xanthophyll,
Ewart* was led to suggest a rather unique hypothesis with reference to
the photosynthetic fixation of carbon. He thinks of the process as
taking place essentially in three stages involving:
1 Zeit. wiss. Phol., 1920, 19: 215; Chem. Abstr., 1920, 14: 3440.
2 Proc. Roy. Soc. (London) 1914, 87B: 556.
3 Thid., 1917, 89B, 1.
3874 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(1) The absorption of carbon dioxide and water by the “phytyl
base” of chlorophyll, forming xanthophyll as an intermediate product;
(2) the oxidation of xanthophyll to the original ‘‘phytyl base’, hexose
sugars, and formaldehyde, the excess of oxygen accumulated (equivalent
to the volume of CO, originally taken up) in state (1) being liberated;
(3) the return of the ‘““phytyl base” to the chlorophyll molecule and the
production of carbohydrates from the formaldehyde.
These possibilities put forth by Ewart are quite original and will be
considered as bold, perhaps, by students of the question, The cycle
can be understood from an inspection of the equations:
(1) 4 CxHs: COO + 76 CO2 + 34 H20 — 4 CuoHssO2 + 93 C2
““PHYTYL BASE”’ XANTHOPHYLL
(2) 4 CsoHssO2 + 42 H20 + 93 O2 > 4 CoHaCOO + 8 CcHi20s + 28 HCHO + 76 O2
—COOH
(3) RETURN OF “‘PHYTYL BASE’’ TO CHLOROPHYLL MOLECULE, CuHsN«MB/_COOCHs
—COOCaHas
The way in which radiant energy is appropriated by plants still
remains to supply cause for much additional work. The partial reduc-
tion of carbon dioxide by silent electric discharges, by discharges under
reduced pressure, and reduction of carbonates by electrolysis have
probably suggested the possibility of electric reduction in the chloro-
plasts. But such a theory is of little help because through it we ap-
parently pass simply from one step in the unknown to another.
But in this connection Noack! points out facts that are not without
interest. Fluorescent substances, e. g., eosin, fluorescein, methylene
blue, etc., act in light as peroxides on plant chromogens. There are,
therefore, light catalyzers. The peroxides come to equilibrium with
atmospheric oxygen. In presence of an oxygen carrier like a manganese
salt, the photodynamic oxidation becomes very powerful. Chlorophyll
in this way may be converted into a peroxide capable of isomerizing the
bicarbonate to a group suitable for reduction; whereby oxygen is evolved
and the original fluorescent color substances again produced. Fluo-
rescent bodies do not act in the same way, however, as metallic light
catalyzers, and, therefore, it must be true that the conversion of radiant
energy by these colors is different from transformations of chemical
energy of the kind on which catalyzers ordinarily depend.
Moore and Webster? have demonstrated the production of organic
matter from carbonic acid solutions containing ferric or uranic hydroxide.
The photosynthesis took place in ordinary light. Baly, Heilbron and
Barker? have confirmed these results. They show that other colored
1Z. Bolan., 1920, 12: 237; Chem. Absir., 1921, 15: 2453.
2 Proc. Roy. Soc., 1914, 87B: 163.
3 J. Chem. Soc., 1921, 119: 1025.
1922] HAND: PRESIDENT’S ADDRESS 375
substances, e. g., malachite green, methyl orange, and so forth, will
produce the same effect. The latter authors have also proved that
formaldehyde and carbohydrates may be obtained from carbonic acid
solutions by exposure to ultra-violet light. No catalyzer is required.
The very short wave lengths bring about the reduction to formaldehyde
and the longer oscillations catalyze its condensation to reducing sugar.
But plants grow in light containing only a very small proportion of
short waves. A photocatalyst is, therefore, essential. Such a sub-
stance must be capable of absorbing light of longer wave-length than
3504. and of then radiating this energy at infra-red frequencies. The
condensation of formaldehyde is favored by longer wave-lengths than
those which induce its formation. The production of carbohydrates,
according to these views, must occur in two stages; and these investiga-
tors look upon chlorophyll as the ideal photocatalyst for both.
When one reflects upon the vast amount of energy stored away in
coal, oil and gas fields and the great quantity being recovered in the
cycle of the seasons, the inefficiency of the agencies that gather it is
very surprising. Brown and Escombe! in a wonderfully complete system
of measurements, obtained data that cause us to hope that the methods
now in use in leaf laboratories will undergo gradual improvement as
the demands of increasing animal life draw more heavily year by year
upon the products of their manufacture. The incident energy is dis-
posed of about as follows:
Per Cent
Energy used for photochemical work............-...seeeeeeees 00.66
BInerpyMIsed COL TLANSPILAGION, 55,4 5: en oes. sod oie 8 6s siasielee © cere dere 48.39
Solaniradiantienergy, CLansMmieted....a <2 co i oie. sv vl cdjec es seiemen« 31.40
Bnerzyalostiby thermal-emission’, «4.5.6 10.00 sis eec ce 4 ae etereiei alors oe 19.55
Rotel ebrccten esach ees 100.00
The factors which govern most largely the speed of the assimilatory
process are naturally intensity of illumination, concentration of CO2,
temperature and number of stomata. Blackman and his students have
given us most of our information regarding the relation of temperature
to speed assimilation. Matthaei? has made careful measurements which
developed an interesting relationship between intensity of illumination,
temperature and amount of CO: assimilation. The general results are
brought together in the diagram which follows, (I).
1 Proc. Roy. Soc. (London), 1905, 76B: 29, 137.
2 Phil. Trans., 1905, 197: 48,
376 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Light <=
Assimilated COz in mgs. per hour and per 50 sq. mm.
Qi
HY aS
ee
I. Relation of Temperature and Intensity of [Illumination to Assimilation, after Matthaei.
The studies of Matthaei emphasize also the marked influence of
temperature upon the rate of intake of CO. (Diagram II). In the
plants under investigation, the rate of carbon fixation increased rapidly
with temperature rise up to the point at which damage to the tissue
occurred. This is plainly brought out in the steep rise and sudden fall
of the curve (Diagram IT). It would prove highly interesting to know
whether a study of numerous kinds of plants would result in similar
conclusions.
Blackman and Smith! with improved apparatus extended their studies
1 Proc. Roy. Soc. (London), 1910, 83B: 374.
1922] HAND: PRESIDENT’S ADDRESS 377
PEE
Mine A
mee Ae sp
_| | 4 eR
10 -O-+ 10 20 7) 40 IC
II. Influence of Temperature on Assimilation, after Matthaei.
Assimilated CO, in 0.1 mg. per hour and per 50 sq. mm.
40
to water plants. In the case of Elodea the data enabled them to show
in a very instructive way the inter-relationship of CO2 concentration,
temperature and intensity of illumination (Diagram III). An extension
of these studies to several kinds of land and water plants would supply
highly desirable information.
The graphic representation of the relationships developed is plain
enough to require no discussion.
When we think of the present state of our information with reference
to the assimilation of carbon and reflect upon the wealth of labor which
has very naturally been lavished upon a problem so fundamental, there
is need to call to mind the fact that the spirit of scientific inquiry per-
mits of no thought of ultimate defeat. Those of this and other
generations who are enabled to interpret that spirit truly possess the
378 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
vision and hold the faith that will conquer. Let us have every assurance
that in this difficult contest, long though it may prove to be, Nature
will lose.
Assimilated CO2 in grams per hour per standard area.
III. Influence of different factors on assimilation in a water plant, Elodea, after Blackman and Smith.
FIRST DAY.
MONDAY—MORNING SESSION.
The thirty-seventh annual convention of the Association of Official
Agricultural Chemists was held at the Washington Hotel, Washington,
D. C., October 24-26, 1921, about a month earlier than usual. It was
found that it would be impossible to secure hotel accommodations dur-
ing the month of November when the Conference for the Limitation of
Armaments was in session.
The meeting was called to order by the President, W. F. Hand of
Agricultural College, Miss., on the morning of October 24, 1921, at
10 o'clock.
REPORT ON WATER.
By J. W. Sate (Bureau of Chemistry, Washington, D. C.), Referee.
During the past year the Weszelszky method! for the determination
of iodine and bromine was studied in the Water and Beverage Labora-
tory by W. E. Shaefer, under the direction of the referee.
Briefly, the Weszelszky method depends upon the selective oxidation
of bromine in acid solution by chlorine water, whereby bromine is set
free, separated from the iodine by distillation in a stream of carbon
dioxide, and absorbed in a bulb containing a solution of potassium hy-
droxide. The iodine, converted into iodic acid in the reaction flask, is
titrated with standard sodium thiosulfate after the addition of some
potassium iodide. The bromine converted into bromate in the absorp-
tion bulb and freed from chlorate by boiling carefully to dryness over a
free flame is likewise titrated with standard sodium thiosulfate.
The kind and quantity of absorbing alkali and the time and tempera-
ture used to remove the chlorate were varied until satisfactory con-
ditions for the recovery of bromine from bromine water were found.
A modified absorption apparatus was constructed, and the kind and
concentration of the acid added to the reaction flask were varied in an
effort to recover bromine quantitatively from potassium bromide and
estimate it by the method found to be satisfactory. Jodine was con-
verted into iodic acid by chlorine water in the reaction flask and esti-
mated in solutions of various acid concentrations.
A rapid and satisfactory modified Weszelszky method for the determi-
nation of small amounts of icdine based on these experiments was de-
1Z. anal. Chem., 1900, 39: 81.
379
380 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
veloped. It was concluded, however, that the Weszelszky method for
bromine in the presence of iodine, however modified, is incapable of
giving satisfactory results on small samples, and its use is not recom-
mended. Since it is proposed to recommend the method for iodine as
an additional tentative method, some results obtained by its use in the
Water and Beverage Laboratory are given below in Tables 1 and 2,
Experiments 55-66. The data in these tables are sufficient also to show
that the method for bromine is unsatisfactory.
TABLE 1.
Results of tests for iodine and bromine using Weszelszky apparatus but modified method* .
IODINE BROMINE
EXPERIMENT} 10% CHLORINE PRESENT AS IODINE PRESENT AS BROMINE
No. POTASSIUM WATER POTASSIUM FOUND POTASSIUM FOUND
HYDROXIDE IODIDE BROMIDE
ce. cc. mgs. mgs. mgs. mgs.
55 10 50 10.00 10.74 10.00 9.35
56 10 50 10.00 10.26 10.00 8.83
57 10 50 20.00 20.00 20.00 14.80
58 10 50 5.00 5.13 5.00 4.07
59 10 50 20.00 19.87 20.00 17.13
*50 cc. of chlorine water+5 cc. of 1 to 1 hydrochloric acid used in reaction flask. Samples heated in
oven for 1 hour.
Ea oe oven for Experiments 55, 56, and 57 was 152°-180°C.; that for Experiments 58 and
59 was 145°-169°C.
TABLE 2.
Results of tests for iodine and bromine using Weszelszky method bul modified apparatus*.
ALKALI FOR ABSORPTION
6 1sT BOTTLE 2ND BOTTLE
Experiment
No. 10% 10% 10% 10%
Solution | Solution | Solution | Solution
potassium | potassium | potassium | potassium
hydroxide | carbonate | hydroxide | carbonate
cc coe ce. cc.
60 7 as 3
61 if BA 3
62 10 ae 5 ai
63 10 35 10 35
64 10 35 10 35
65 224 224 223 22
66 224 22 224 224
IODINE
PRESENT
mgs.
10.00
10.00
5.00
10.00
10.00
10.00
10.00
IODINE
FOUND
mgs.
10.06
9.97
5.05
10.15
10.07
10.13
10.06
BROMINE
PRESENT
mgs.
10.00
10.00
5.00
10.00
10.00
10.00
10.00
BROMINE
FOUND
*Kind and concentration of absorbing alkali varied. 5 cc. of 1 to 1 hydrochloric acid and 50 cc. of chlorine
water were added to the reaction flask. Samples heated in oven for 1 hour.
+The amounts of alkali were added to the absorption bottles and diluted to 150 ec.
The results obtained on Experiments 57-66, in Tables 1 and 2, show
that this method gives very satisfactory results for iodine provided
1922] SALE: REPORT ON WATER 381
5 ec. of 1to1 hydrochloric acidis used in the reaction flask. The average
error on 10 consecutive iodine determinations on samples of 5 to 20 mgs.
(Experiments 57-66) was only 0.081 mg. or 0.74 per cent. The results
of Experiments 55 and 56 are omitted from this average because they
were the first ones made, and the solution in the reaction flask was not
boiled sufficiently long to remove all the chlorine. The average error
made by W. F. Baughman’ on seven consecutive determinations of
iodine on samples of 20.1 to 60.2 mgs. by the permanganate method
was 0.229 mg. or 0.66 per cent.
The modified method for iodine follows:
IODINE IN THE PRESENCE OF CHLORINE AND BROMINE.
APPARATUS.
Glass-stoppered flask of 200-400 cc. capacity provided with inlet and outlet tubes.
Tall absorption bottle,
REAGENTS (1 to 1)
(a) Hydrochloric acid (1 to 1).
(b) Chlorine water freshly prepared.
(c) 10% potassium carbonate solution.
(d) Potassium iodide solution, 20% free from iodate.
(e) 0.05N sodium thiosulfate solution.
(f) Starch solution.
DETERMINATION.
Place sample, contained in a yolume of not more than 25 cc., in the glass-stoppered
flask. The inlet tube should have a stop-cock and reach nearly to the bottom of the
flask. Add 5 cc. of 1 to 1 hydrochloric acid to the sample, insert the stopper and add
50 ce. of freshly prepared chlorine water through the inlet tube. Place the outlet tube
in a tall bottle containing 35 cc. of a solution of potassium carbonate (C) diluted to
150 cc., heat the reaction flask and boil gently until most of the chlorine and bromine
has been distilled into the alkali. It is convenient to have a 25 cc. bulb blown into the
middle of the outlet tube in order to Jessen the danger of the absorbing solution running
back into the reaction flask. Connect the inlet tube to a carbon dioxide generator
and complete the distillation by simultaneous boiling and bubbling of carbon dioxide
through the sample. Continue this for 10 minutes, testing for presence of chlorine
and bromine by holding a piece of starch iodide paper at the end of the outlet tube;
remove the source of heat, and bubble carbon dioxide through the apparatus until it
is cool. Add 5 cc. of a solution of potassium iodide (d), and titrate the liberated
iodine with 0.05N sodium thiosulfate solution (€) in the usual way.
Methods for the quantitative determination of small quantities of
lead, copper and zinc in waters, when all three metals together with iron
are present, have been collated. Synthetic samples have been analyzed
by these methods, but additional work is needed before the methods
can be accepted as completely satisfactory. Methods of water analysis
1J. Ind. Eng. Chem., 1919, 11: 563.
382 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMIstTs [Vol. V, No. 3
are incomplete unless methods for metals which are frequently sought
are included. While methods which involve electrolytic deposition of
metals are no doubt satisfactory, it is not believed that the average
laboratory is equipped to make the determinations in this way; conse-
quently, the methods which have been collated and in part tested are
colorimetric. In the following methods the coloring matter is elimi-
nated by precipitating the metals with ammonium sulfide. The lead
is separated as lead sulfate and determined colorimetrically as lead
sulfide. The copper is separated as copper sulfide and determined
colorimetrically with potassium ferrocyanide. In the filtrate from the
copper, the iron is held in solution with citric acid. The zinc is pre-
cipitated as zinc sulfide and determined turbidimetrically with potas-
sium ferrocyanide.
The methods in detail follow:
LEAD, COPPER AND ZINC (Quantitative)!, 2.
(Use when water contains small quantities of metals.)
REAGENTS (SPECIAL).
(a) Ammonium acelate solution—Dissolve 200 grams of the salt in water and make
up to 500 ce.
(b) Dilute ammonium acetate solution —Dilute 50 cc. of (A) to 500 ce.
(Cc) 3.5% potassium ferrocyanide solution.
(d) Stange lead solution—Add sulfuric acid in slight excess to a strong solution
of lead acetate. Filter off the lead sulfate and wash free from acid with water. Dis-
solve the lead sulfate in ammonium acetate solution (a), make up to known volume
and determine lead as lead chromate by precipitating with potassium bichromate
solution. Dilute the stock solution so that 1 cc. will contain 0.1 milligram of lead.
(e) Standard copper solution—Dissolve about 20 grams of copper sulfate crystals
(CuSO,.5 H:O) in water, add 1 cc. concentrated sulfuric acid and dilute to 500 ce.
Determine the copper in 50 cc. of this solution as copper oxide (CuO) by precipitation
with potassium hydroxide solution. Dilute the stock solution so that 1 cc. contains
0.1 milligram of copper.
(f) Standard zine solution—Dissolve C. P. zinc in hydrochloric acid and dilute so
that 1 cc. contains 0.1 mg. of zinc.
($) 50% citric acid solution.
(h) 2% ammonium thiocyanate solution.
DETERMINATION.
(See also modified procedure.)
Acidify with hydrochloric acid from 1% to 2 liters of the sample. Concentrate in a
porcelain casserole by heating slowly over the open flame to a volume of about 75 ce.
Add sufficient ammonium chloride (about 2.0 grams) to hold magnesium in solution
and assist in separation of sulfides. Add about 1 cc. excess of ammonia and saturate
with hydrogen sulfide. Cover dish and let stand about 2 hours, add more ammonia
and hydrogen sulfide, boil a few minutes, let precipitate settle, filter and wash pre-
cipitate once with hot water. The precipitate will contain all the iron, lead, copper
1 Report Mass. State Board of Health, 1898, 582-3.
2 J. Ind. Eng. Chem., 1921, 13: 696.
1922] SALE: REPORT ON WATER 383
and zinc, and the coloring matter will be in the filtrate. Place filter and precipitate in
a small porcelain casserole; add 50 cc. of dilute nitric acid (1 to 5) and boil. Filter and
wash free from acid, cool filtrate and add 5 cc. of dilute (1 to 1) sulfuric acid, con-
centrate carefully by boiling and heat until copious fumes of sulfuric acid are given off.
Transfer to a beaker with the aid of water, add an equal volume of alcohol (95%), let
stand overnight, filter off the lead sulfate and wash with dilute alcohol (50%) until
free from iron. Collect the filtrate which contains iron, copper and zinc in a 250 ce.
beaker.
LEAD.
- Boil the filter containing the lead sulfate with about 40 cc. of the ammonium acetate
solution (a), in a small porcelain casserole, filter and wash once or twice with hot
dilute ammonium acetate solution (b) and twice with water. Make filtrate up to
definite volume. Add freshly prepared hydrogen sulfide water and a few drops of
acetic acid to an aliquot portion. Compare the color obtained with a set of standards
made by treating various amounts of the standard solution of lead sulfate (d), with
hydrogen sulfide water.
COPPER.
Boil the moderately acid filtrate, which contains iron, copper and zinc, to remove
alcohol; adjust solution to a volume of about 200 cc. and add 1 gram of ammonium
chloride. Heat to boiling, saturate with hydrogen sulfide gas, boil to remove precipi-
tate sulfur, cover beaker, let stand about 2 hours or until supernatant liquid becomes
clear, filter and wash the copper sulfide without intermission with water containing
hydrogen sulfide. Collect filtrate in porcelain casserole. Dissolve the copper sulfide
in hot dilute nitric acid (1 to 5), evaporate to dryness, take up in water, filter if solution
is not clear, and adjust solution to a volume of 100 cc. Add to an aliquot, 2-3 drops of
potassium ferrocyanide solution (C€). Compare color obtained with standards con-
taining proper amounts of standard copper solution (€), treated in the same way.
ZINC.
Boil the acid filtrate from the copper sulfide precipitation to remove hydrogen sulfide,
cool, neutralize with ammonium hydroxide and add 10 ce. of citric acid solution (&).
Heat to boiling and if no calcium citrate separates, add small quantities of calcium
carbonate until a precipitate of about 1 gram of calcium citrate is formed. Pass hy-
drogen sulfide through the solution until it is cool. Let stand several hours, part of
the time on water bath, until supernatant liquid is clear. Filter, wash with ammonium
thiocyanate solution (h), and dissolve precipitate on the filter with hot dilute hydro-
chloric acid. If filtrate is reddish in color, reprecipitate the zinc as before. Dispel
turbidity of filtrate due to colloidal sulfur by boiling. When filtrate is clear and color-
less, dilute an aliquot to 45 cc. in a 50 cc. Nessler jar. Add 5 cc. of potassium fer-
rocyanide solution (C), mix quickly and compare the turbidity with standard zinc
solutions by viewing longitudinally the jars held over a sheet of fine print. Prepare
the standards by mixing definite volumes of standard zinc solution (f), 3 cc. of con-
centrated hydrochloric acid, water to make 45 cc. and 5 ce. of potassium ferrocyanide
solution (C). The unknown solution should contain a volume of concentrated acid
equivalent to that in the standards. Do not use zinc borosilicate glassware in this
determination.
MODIFIED PROCEDURES.
(Coloring matter absent; iron, lead and zinc present.)
Add 5ce. dilute (1 to 1) sulfuric acid to the sample, evaporate nearly to dryness and
heat until copious fumes of sulfuric acid are given off. Filter off the lead sulfate and
follow detailed procedure.
384 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Procedure for lead only.
(Coloring matter present, iron present to extent of 1.0 mg. or less in the quantity of
sample taken for analysis, and copper and zinc absent.)
After heating until fumes of sulfuric acid are given off, in the regular procedure,
transfer to a beaker with the aid of water. Add 25-40 cc. of ammonium acetate
solution (a), heat to boiling and precipitate the iron with ammonia. Filter, wash
with dilute ammonium acetate solution (b), and water. Acidify filtrate slightly
with acetic acid and determine lead colorimetrically in the filtrate by the addition of
hydrogen sulfide water.
Procedure for lead only.
(Coloring matter, iron, zinc and copper absent.)
Add 5 cc. of concentrated sulfuric acid to the sample, evaporate nearly to dryness
and heat until copious fumes of sulfuric acid are given off. Transfer to a beaker with
the aid of water, add 25-40 cc. of ammonium acetate solution (a), and determine
lead colorimetrically by the addition of hydrogen sulfide water.
It will be recommended that the above methods be given careful
study next year.
In 1919, the association extended the methods of water analysis to
cover allied products, such as brine and salt. The standard for salt
which has been promulgated in connection with the enforcement of the
Federal Food and Drugs Act provides that table salt (dairy salt) shall
contain on a water free basis, not more than 1.4 per cent of calcium
sulfate, 0.5 per cent of calcium and magnesium chlorides and 0.1 per
cent of matters insoluble in water. It is important, when the purity
of shipments of salt is questioned, that the methods of analysis be
uniform and specific. The referee, at this time, is in a position to sub-
mit only methods for determination of moisture, matters insoluble in
water and matters insoluble in acid. They are as follows:
SALT.
The samples should be representative. If the shipment is packed in bags or other
containers, collect one sample from-each of five containers.
MOISTURE.
DETERMINATION.
Place 10 grams of the well-mixed sample in a weighed Erlenmeyer flask, capacity
200 ce. Insert small funnel in neck. Ignite to constant weight over low flame of gas
stove. Call the loss moisture and express in per cent.
MATTERS INSOLUBLE IN WATER.
DETERMINATION.
Treat 10 grams of the well-mixed sample with 200 cc. of water and let stand 30 min-
utes, stirring frequently. Filter through Gooch crucible with mat, dried at 110°C.
Wash residue free from chloride. Dry to constant weight at 110°C. Express results
in per cent. If residue exceeds 0.1% determine its nature.
1922] SALE: REPORT ON WATER 385
MATTERS INSOLUBLE IN ACID.
DETERMINATION.
Treat 10 grams of the well-mixed sample with 190 cc. of water and 10 ce. of con-
centrated hydrochloric acid, boil 2-3 minutes, let stand 30 minutes, stirring frequently.
Filter through Gooch crucible with mat, dried at 110° C. Express results in per cent.
Methods of combining radicals are not uniform among water analysts.
While there is a wide diversity of opinion as to the advisability of ex-
pressing water analyses in the form of salts, the fact remains that in
the administration of Federal and State laws it is usually necessary to
present to physicians and to the court water analyses expressed in the
form of salts. For this reason, the tentative method! of reporting
results has been extended for the benefit of the analyst who does not
continually make analyses of water. The principles involved in the
tentative methods adopted by the association have been retained. The
extended method follows in detail:
METHOD OF REPORTING RESULTS.
Report radicals and anhydrous salts in terms of milligrams per liter or, in the case
of highly concentrated waters, in terms of grams per liter. For the benefit of physi-
cians, in the case of medicinal waters, report also the salts in terms of grains per quart,
using the factor 0.014604 to convert milligrams per liter to grains per quart. In report-
ing salts in terms of grains per quart, convert those salts which have water of crystal-
lization to the hydrated form as expressed in the U. S. Pharmacopoeia and National
Formulary, and convert the bicarbonates of magnesium and of calcium to equivalent
amounts of the respective carbonates. Use the following factors in these calculations:
From NaSO; to NaSO, . 10 H.0 =2.2682;
MgSO, to MgSO; . 7 H.0=2.0476;
CaSO, to CaSO, . 2 H2O0 =1.2647;
Mg(HCO:)2 to MgCO;=0.5762;
Ca(HCO;)2 to CaCO;=0.6174.
Calculate other less used factors and employ them when necessary.
In special cases, as in the analysis of drainage waters, boiler waters, etc., do not
report the salts in grains per quart but report instead the reacting values of the radicals.
When a complete analysis is made report the error of analysis and state how it is dis-
tributed. Report only significant figures.
Report iron and aluminium together when present in unimportant quantities and in
calculations consider them as iron. When iron and alumfnium are present in larger
quantities, make the separation and report each separately.
In calculating the hypothetical combinations of acid and basic ions, join nitrous,
nitric, metaboric and arsenic acids to sodium; iodine and bromine to potassium; and
phosphoric acid to calcium. Assign the residual basic ions in the following order:
Ammonium, lithium, potassium, sodium, magnesium calcium, strontium, manganese,
iron and aluminium—to the residual acid ions in the following order: Chlorine, sulfuric
acid ion, carbonic acid ion and bicarbonic acid ion. In case the bicarbonic acid ion is
not present in a sufficient quantity to join with all the calcium, the residual calcium is
joined to silica to form calcium silicate, and manganese iron and aluminium are calcu-
lated to the oxids Mn;0,, FeO; and Al.O;, respectively.
1 Assoc. Official Agr. Chemists, Methods, 1920, 21-41.
386 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Use equivalent combining weights or their reciprocals in uniting the radicals, and
when necessary for the purpose of comparison, in reducing salts to radicals and reuniting
the radicals in the order specified on page 385.
TABLE 3.
Equivalent combining weights and their reciprocals based on international atomic
weights, 1921.
RECIPROCALS OF
EQUIVALENT EQUIVALENT
NEGATIVE EQUIVALENT NEGATIVE
COMBINING COMBINING
RADICALS WEIGHIS COMBINING RADICALS WEIGHTS
WEIGHTS
NO, | 46.008 0217 SiO, 30.15
NO; 62.008 -01613 SiO; 38.15
BO, 42.9 .02331 O 8.0
AsOx 46.32 .0216 F 19.0
I 126.92 -0079 (Gal 35.46
Br 79.92 01251 SO, 48.03
PO; 31.68 03156 CO, 22.0025
HS 33.068 .0302 CO; 30.0025
Ss 16.03 .0624 HCO; 61.013
Positive Positive
radicals radicals
NH, 18.04 .0554 Sr 43.815
Li 6.94 -1441 Ba 68.685
K | 39.10 02557 Mn 27.465
Na 23.00 .043478 Fe’ 27.92
Mg 12.16 -082237 Fe’”’ 18.6133
Ca 20.035 -049913 Al 9.0333
RECIPROCALS OF
EQUIVALENT EQUIVALENT
EQUIVALENT
SALTS COMBINING CoMBrViNG SALTS COMBINING
WEIGHTS WEIGHTS
WEIGHTS
NH.C1 53.50 0187 MgCl, 47.62
LiCl 42.40 0236 MgSO, 60.19
LivSO, 54.97 -0182 MgCoO; 42.1625
LisCO; 36.9425 0271 Mg(HCO;)2 73.173
LiHCO; 67.953 .0147 Mg(NOs)2 74.168
KCl 74.56 .0134 CaCl, 55.495
K.SO, 87.13 .01148 CaSO, 68.065
K,CO; 69.1025 -01447 CaCO; 50.0375
KHCO; 100.113 -00999 Ca(HCOs)2 81.048
I 166.02 -0060 CaSiOg 58.185
K Br 119.02 -00840 Ca;(PO)s 51.715
NaCl 58.46 .0171 SrSO, 91.845
Na Br 102.92 -0097 SrCO; 73.8175
Nal 149.92 .0067 Sr(HCOQs)> 104.828
NaSO, 71.03 -01407 BaSO; 116.715
Naz CO; 53.0025 0189 Ba(HCOs)2 129.698
NaHCO, 84.013 01190 MnSO, 75.495
NaNO, 69.008 .0145 MnCoO,; 57.4675
NaNO; 85.008 .01176 Mn(HCOs)> 88.478
NaBO, 65.9 -01517 eSOy 75.95
NazAsO, 69.32 .0144 Fe2(SOs)s 66.6433
aF 42.00 -0238 Fe.CO; 57.22833
NaHS 56.068 0178 Fe(HCOs)> 88.933
NaS 39.03 0256 FeO; 26.613
Na.SiO; 61.15 0163 Al2(SOy)s 57.063
A nde Al.Os 17.033
i
RECIPROCALS OF
EQUIVALENT
COMBINING
WEIGHTS
-0332
0262
-1250
-0526
028201
RECIPROCALS OF
EQUIVALENT
COMBINING
WEIGHTS
-021000
-016614
02372
-01367
-01348
-018020
-014692
-0200
01234
0172
-0193
-O111
-0135
-0095
-0086
-0077
-0132
0174
-0113
013166
-015005
-0175
-01124
0376
.017524
0587
an
My
1922} SALE: REPORT ON WATER 387
The equivalent combining weight of a radical is obtained by dividing its weight by
its valence. The equivalent combining weight of a salt is obtained by dividing its
molecular weight by the product of the valency of the basic element and the
number of atoms of the basic element in the salt. The equivalent weights and their
reciprocals (reaction coefficients) for the radicals and salts ordinarily used are set forth
in Table 3.
The procedure in calculating the hypothetical combinations by the
use of the equivalent combining weights and their reciprocals is as
follows:
Multiply the weights obtained, expressed in milligrams per liter, or, in the case of
highly concentrated waters, in grams per liter, for each radical to be combined, by the
corresponding reciprocal of the equivalent combining weights. If the sodium and
potassium are to be determined by calculation, as is frequently the case, subtract the
sum of the values obtained (reacting values) for the basic radicals from the sum of the
reacting values for the acid radicals. The difference represents the reacting value of
the undetermined sodium and potassium. When all the constituents in the water
have been determined the sums of the reacting values of the acid and of the basic
radicals should be very nearly the same. In this case, if the difference is reasonable
and well within the limit of accuracy of the methods employed, it may be distributed
equally among all the radicals determined, or among those which the analyst believes
to be less accurate than the others. If the difference is unreasonably great, repeat the
analysis in whole or in part. The sums of the reacting values of the acid and basic
radicals must be equal before proceeding with the calculation. Obtain the reacting
values of the salts by subtracting in succession the reacting values of the radicals in
the specified order. For example, the reacting values for the radicals in a concentrated
water are as follows: Cl, 21.573; SOx, 4237.934; COs, 18.498; HCO:, 20.487; Na, 528.231;
Mg, 3747.451 and Ca, 22.810. Then 528.231—21.573 (reacting value of Cl and of
NaCl) =506.658 (remaining reacting value of Na); 4237.934—506.658 (reacting value
of Na:SO.) =3731.276 (remaining reacting value of SO;); 3747.451 —3731.276 (reacting
value of MgSO;)=16.175 (remaining reacting value of Mg); 18.498—16.175 (reacting
value of MgCQ;)=2.323 (remaining reacting value of CO;); 22.810—2.323 (reacting
value of CaCO;) =20.487 (remaining reacting value of Ca and also the reacting value
of HCO; and of Ca (HCO;)2). The following reacting values for the salts are thus
obtained: NaCl, 21.573; Na2SOx, 506.658; MgSO, 3731.276; MgCOs, 16.175; CaCOs,
2.323; Ca (HCO;)s, 20.487. To convert these figures to milligrams per liter of the
respective salts divide each of them by the reciprocal of the equivalent combining
weights of the salt in question or preferably multiply each of them by the equivalent
combining weight of the respective salt.
It is reeommended—
(1) That the method for the determination of iodine in the presence
of chlorine and bromine, page 381, be adopted as a tentative method.
The method has not been published in the Proceedings as provided by
By-law No. 7.
(2) That the method for the determination in salt of moisture, mat-
ters insoluble in water and matters insoluble in acid, page 384, be adopted
as a tentative method.
(3) That the method of reporting results of water analyses, page
385, be adopted as a tentative method.
388 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(4) That the tentative method of reporting results of water analyses!
be dropped.
(5) That the quantitative methods for the determination of small
quantities of copper and zinc in waters, page 382, be studied during the
next year.
REPORT ON TANNING MATERIALS AND LEATHER.
By F. P. Verrcn (Bureau of Chemistry, Washington, D. C.), Referee.
Work of the referee continues to be materially hampered by the fact
that so few members of this association are directly interested in the
subject of analysis of tanning materials and leather. It is believed,
however, that despite this handicap the association should continue
work of this character because as leather-making materials become
scarcer greater interest will be taken. Furthermore, the methods of
this association should apply to all of those materials which are of
immediate and direct interest to the farm population.
In view of this lack of active interest, to save time and avoid un-
necessary printing, the referee will refrain from giving the details of the
methods employed. This report will be confined to a general state-
ment of the various problems which have been studied, to the conclusions
reached and to recommendations for further work. Those who may be
interested in the details of the methods which have been studied in
connection with the analysis of tanning materials and leather are re-
ferred to the Journal of the American Leather Chemists Association
and to the Journal of the Society of Leather Trades Chemists for the past
five years.
ANALYSIS OF LEATHER.
EFFECT OF ATMOSPHERIC HUMIDITY ON DETERMINATION OF MOISTURE.
During the past year the referee and several collaborators continued
the work on the effect of atmospheric humidity and temperature on
the determination of moisture in leather and tanning materials. It was
found that the atmospheric humidity existing at the time of the deter-
mination of moisture in the sample may affect the moisture result as much
as 14 per cent, and it is believed that this is true of practically all
organic materials. Though the effect is observable in the vacuum
oven, it is not quite as marked as when the drying is done in the
ordinary hot-water oven.
It was observed also that in drying leather over very long periods at
the same atmospheric humidity there is a constant, but very small,
loss in weight, the nature of which was not determined.
1 Assoc. Official Agr. Chemists, Methods, 1920, 38.
1922) VEITCH: REPORT ON TANNING MATERIALS AND LEATHER 389
Work on this subject will be continued during the coming year, and
efforts will be made to secure more extended cooperation within this
association.
SOLVENTS FOR EXTRACTION OF GREASES.
Some work was done to determine the proper solvent to use in extract-
ing grease, oils and soaps from leather. Petroleum ether does not extract
all of the waxes, the oxidation products of oils and fats or the soap
which may have been added to the leather in currying. No solvent has
been found which will take these out without removing tannins or other
constituents which should be retained. '
A number of investigators, including Wilson and Kern, Levi and
Orthmann, and committees of the American Leather Chemists Asso-
ciation and of the Society of Leather Trades Chemists of England,
have worked extensively along this line. Their complete papers or
abstracts are to be found in the Journal of the American Leather Chem-
ists Association, 1918 and since.
After a full consideration of previous work, the referee decided to
confine investigations to the effect of ethyl ether and chloroform as
compared with petroleum ether. Without going into the analytical
details, which are to be found in the Journal of the American Leather
Chemists Association, it may be said: (a) That chloroform is the best
solvent so far found for greases, waxes and oxidation products in leather;
(b) that dry Ivory soap alone is practically insoluble in chloroform and
petroleum ether; (c) that the presence of moisture in leather will increase
the quantity of soap fats extracted by chloroform and by petroleum ether,
but the effect of the quantity of moisture usually present in well air-dried
leather is small; (d) that the presence of tannic acid in leather, probably by
decomposing the soap and setting free the fatty acids, increases the
solubility of soap and fats very greatly but mostly in chloroform;
(e) that the grease extracts from a material containing uncombined
tannic acid contains small quantities of tannic acid or related bodies
and loses weight indefinitely in drying; (f) that magnesium salts added
to leather will lead to the extraction of the soap as 2 whole if opportunity
is given for the formation of magnesium soaps since the latter are very
soluble both in chloroform and petroleum ether; (g) that calcium soaps
are extracted by chloroform in a colloidal solution but are practically in-
soluble in petroleum ether; and (h) that while chloroform is a much
better solvent for the fats of soap added to the leather than is petroleum
ether, all the soap fats are probably not removed by chloroform when
the extraction is made as usual. Since soaps are often used in currying
leather, any undecomposed particles which may remain in the leather
will probably be removed in the water extraction of the leather and the
results on fat, if it has not previously been removed with the solvent,
390 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
are too low. More work needs to be done on the solubility of soaps
from different greases before it will be known how serious this error
may be.
DETERMINATION OF TANNIN.
That the methods now used for the determination of tannin in tan-
ning materials do not give accurate results but indicate a higher content
of tannin than the material actually contains, has long been known.
In this connection the present referee, in a paper, ‘““A Discussion of
Methods for the Estimation of Tannin’, read before the annual meet-
ing of this association in 1904, stated:
The method known as the hide-powder method, while not formally adopted as official
by this association, is used exclusively for the estimation of tannin in tanning materials.
It is well recognized, however, that the method yields inaccurate results. The chief
sources of error appear to be a continuous absorption of solids from the solution by the
filter paper during the preceding determination of soluble solids, and an undoubtedly
greater error due to the absorption of coloring matter and other nontannin matters by
the hide powder. The first may produce a minus error, the latter produces a plus
error. Experimental demonstration is hardly needed of the fact that hide powder
removes other constituents than tannin from tannin solutions brought in contact with
it, as such absorption, occlusion, etc., is a common property of all precipitates or other
solid matter in contact with solutions of solids, and prolonged washing is frequently
required to free them from materials held in this way. Nevertheless we have experi-
ments showing that in addition to tannin most of the nontannin constituents common
to solutions of tanning materials are absorbed to a serious extent by hide powder, as
may be seen from the work of Proctor and Blockey*, who found the absorption of gallic
acid, quintol, catechol, and catechin when present in solution with gallotannic acid or
quebracho tannin was from 44 per cent to 106 per cent of the amount present.
Dextrin and glucose were absorbed in very much smaller quantities or lowered the
absorption of the tannin.
A lively appreciation of these facts, together with the time and work required to
obtain results, has greatly stimulated the search for more accurate and quicker methods.
The methods and proposals which have appeared as a result of this activity are of such
a character that, while I cannot offer anything better than the hide-powder method, a
few words of criticism and a brief statement of what must be avoided would seem to be
timely, and may be of service to many who at first sight are favorably impressed with
some of these methods.
Although many varied procedures have been proposed, the indirect
method of determining tannin by difference through removal with a
standard hide powder remains preferred, and, indeed, the only recog-
nized procedure, simply because a better one is not known. The chem-
ists interested in tanning and leather have sought in vain a direct method
for estimating tannin, unless the procedure which has been studied
more recently by Wilson and Kern*® should yield a satisfactory method.
1U. S. Bur. Chem. Bull. 90: 215.
2 J. Soc. Chem. Ind., 1903, 22: 482.
3 J. Am. Leather Chem. Assoc., 1920, 15: 295.
1922| | VEITCH: REPORT ON TANNING MATERIALS AND LEATHER 391
This procedure is now under investigation by the referee with a view
to determining, more definitely than has so far been done, its reliability
and accuracy. In this work the referee hopes to secure the cooperation
of the other members of this association during the coming year.
The problem is complicated materially by the absorption of catechin
as shown by Proctor and Blockey!. These investigators make the
following statement concerning catechin:
Experiments were also made with catechin, which stands in a different relation from
the other non-tanning substances to tannins, since the catechins are not tannin deriva-
tives, but rather the root substances from which the catechol tannins themselves are
derived by abstraction of water. It will be seen that the catechin experimented with
was practically wholly absorbed by the hide-powder in the filter method, but this can
hardly be considered an error, since it is probable that during the tanning process the
catechin becomes gradually dehydrated and converted into an actual tannin. The
specimen used was obtained as pure from Merck, and was white and crystalline, but
showed itself more soluble in cold water than is usually stated to be the case. A sat-
urated solution in cold water showed decided tanning properties, producing an under-
tanned yellowish leather. These tanning properties were distinctly increased by
boiling the solution for some hours before use, and both the solution itself and the
leather produced became decidedly redder in colour. One of us proposes to investigate
this point more completely, as it is of considerable practical importance in view of the
large quantity of catechin contained in gambier and cutch.
These observations have been confirmed recently by Wilson and
Kern?, and the fact that such changes take place during the analytical
processes may introduce errors in the process itself, or, if they take
place, as they probably do, in the tan yard, may leave in question the
procedure which may be employed in the determination of so-called
tannin.
RECOMMENDATIONS.
It is reeommended—
(1) That work be continued on the solubility of various soaps in differ-
ent solvents and upon a method, probably first breaking up the soap
by heating the leather with an acid, for the extraction of total soaps in
leather. "
(2) That investigations of a direct method for the determination of
tannin in tanning materials be continued.
1 J. Soc. Chem. Ind., 1903, 22: 482.
2 J. Am. Leather Chem. Assoc., 1920, 15: 295.
392 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
REPORT ON INSECTICIDES AND FUNGICIDES.
By J. J. T. GRanAm (Bureau of Chemistry, Washington, D. C.), Referee.
The cooperative work on insecticides and fungicides for 1921 included
a study of methods for the determination of total arsenic, arsenious
oxide and calcium oxide in calcium arsenate; for the determination of
arsenious oxide and zinc oxide in zinc arsenite; and for the determina-
tion of lead oxide, zinc oxide and copper in a mixture of Bordeaux, lead
arsenate and zinc arsenite. Methods for the determination of arsenious
oxide in Paris green, total arsenic in London purple, and magnesium
oxide in magnesium arsenate were also considered by the referee.
Reports were received from seven analysts in three laboratories.
The following methods were tested:
ZINC ARSENITE.
The zinc arsenite sent to the collaborators was a commercial sample from a well-
known insecticide manufacturer.
ZINC OXIDE,
Mercury-Thiocyanate Method'.
REAGENT.
Dissolve 27.0 grams of mercuric chloride and 38 grams of potassium thiocyanate in
1 liter of water. In lieu of the potassium thiocyanate, 30 grams of ammonium thio-
cyanate may be used.
DETERMINATION.
Weigh 2.0 grams of the sample and transfer to a beaker. Dissolve in 80 ce. of hydro-
chloric acid (1 to 3), wash into a 200 cc. volumetric flask, and dilute to
volume. Thoroughly mix the solution and filter through a dry filter. Transfer a
25 cc. aliquot to a beaker and add 5 cc. of concentrated hydrochloric acid. If there
is much iron present, reduce it at this point by adding a little sodium bisulfite and
heating on the steam bath until the odor of sulfur dioxide has largely disappeared.
Cool, dilute to about 100 cc. and add 35-40 cc. of the mercury-thiocyanate reagent
with vigorous stirring. Allow to stand at least an hour with occasional stirring. Filter
through a tared Gooch crucible, wash with water containing 20 cc. of the mercury-
thiocyanate reagent per liter, and dry to constant weight at 105°C. From this weight
calculate the per cent of zinc oxide in the sample, using the factor 0.16331.
ARSENIOUS OXIDE.
REAGENTS.
(a) Starch indicator.—Prepare as directed under Paris green'.
(b) Standard arsenious oxide solution.—Prepare as directed under Paris green’.
(c) Standard iodine solution —Prepare as directed under Paris green?.
(d) Standard bromate solution —Dissolve 1.688 grams of pure potassium bromate
or 1.525 grams of pure sodium bromate in water and dilute to 1 liter. One cc. of this
1 Trans. Am. Inst. Met., 1914, 8: 146; J. Am. Chem. Soc., 1918, 40: 1036.
2 Assoc. Official Agr. Chemists, Methods, 1920, 53.
1922] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 393
solution is approximately equal to 0.00300 gram of arsenious oxide. To standardize,
transfer 25 cc. aliquots of the standard arsenious oxide solution to 500 cc. Erlenmeyer
flasks, add 15 cc. of concentrated hydrochloric acid, dilute to 100 ec., heat to 90°C. and
titrate with the bromate solution, using 5 drops of a 0.2% solution of methyl orange as
indicator. The indicator should not be added until near the end of the titration, and
the liquid should be agitated continuously in order to avoid local excess of the bromate
solution. The bromate should be added very slowly when approaching the end of the
titration, the end point being shown by a change from red to colorless.
TABLE 1.
Cooperative results on zine arsenite.
ARSENIOUS OXIDE.
ANALYST ZINC OXIDE
BROMATE METHOD
HEDGES
Hot Cold at
per cent per cent i per cent per cent
L. N. Markovitz, Bureau of 56.40 41.16 41.18 41.28
Chemistry, Washington,D.C. 56.40 41.22 41.18 41.30
IAWETAPEH <ecles Sos vee sos 56.40 41.19 41.18 41.29
H. L. Fulmer, Guelph, Can- 56.46 eeoe
ada. 56.39 mctsae
PVELARE td «2's. wslylee tas 56.43
J. J. T. Graham. 56.80 41.06 41.12 40.99
56.73 41.06 41.12 40.94
56.87 41.12 41.12 40.99
FAVELA E oro. </<)c.o\c o-«.2 s14,5°908 « 56.80 41.08 41.12 H 40.97
Percy O’Meara, E. Lansing, 56.44 41.16 41.20 41.50
Mich. 56.56 41.08 41.16 41.80
ayasate aac Gatocye 42.10
LAGERS SaaS SURO OO Se CEE 56.50 41.12 41.18 41.80
C.M. Smith, Bureau of Chem- 56.59 41.08 41.08
istry, Washington, D. C. 56.51 41.08 41.08
56.59 41.14 ~ 41.14
56.45 41.14 41.14
56.46 41.08 41.08
AEDES id Or DORON 56.52 41.10 41.10
F. L. Hart, Bureau of Chem- Mizee 41.26 41.20 41.26
istry, Washington, D. C. EG 41.22 41.16 41.22
12006 41.29 41.16 Sita
PAV ELAR ERO cette. ie claisG 5 5» 41.26 41.17 41.24
General Average.......... 56.55 41.14 41.13 41.34
394 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
DETERMINATIONS.
Bromate Method.—(1) Transfer a 25 cc. aliquot of the solution prepared for the
determination of zinc to a 500 cc. Erlenmeyer flask, add 20 cc. of concentrated hydro-
chloric acid and dilute to 100 cc. Heat to 90°C. and titrate with the standard bromate
solution.
(2) Proceed as in (1) without heating the solution.
Hedges Method.
Proceed as directed under Paris green’.
DISCUSSION.
The results for zinc oxide agree very well. The method is easy to manipulate and is
much preferable to other methods now in use for the determination of zinc. The
results for arsenious oxide by the bromate method give very close checks, the maximum
variation of all the results being 0.23%. They show that with careful work the
method is accurate whether carried out at ordinary room temperature or at 90°C.,
although the end point is a little sharper at the latter temperature. This titration,
influenced by the presence of nitrates in the sample, will be discussed more fully under
calcium arsenate.
CALCIUM ARSENATE.
The sample used was prepared from commercial materials, by pouring a solution of
arsenic and arsenious acids into milk of lime, with vigorous stirring. After standing
for some time, the mixture was filtered, dried, passed through a 40 mesh sieve and
thoroughly mixed. The arsenious oxide was added in order to test the method for
arsenious oxide.
TOTAL ARSENIC.
REAGENTS.
(a) Starch indicator.—Prepare as directed under Paris green’.
(b) Standard arsenious oxide solution.—Prepare as directed under Paris green?. To
convert arsenious oxide to arsenic oxide use the factor 1.16168.
(€) Standard iodine solution—Prepare as directed under Paris green’.
(d) Standard bromate solution.—Prepare as directed under zinc arsenite, page 392.
DETERMINATION.
Official Distillation Method.
Proceed as directed under Paris green*, using an amount of the sample equal to the
arsenic oxide equivalent of 500 cc. of the standard iodine solution and titrating 200 ce.
of the distillate. The number of cc. of standard iodine solution used represents directly
the total per cent of arsenic in the sample expressed as arsenic oxide.
Bromate Method*.
Proceed as directed under the official distillation method until the distillate is made
to volume in a liter graduated flask, using an amount of the sample equal to the arsenic
oxide equivalent of 500 cc. of the standard bromate solution. Transfer 200 ce. ali-
quots of the distillate to 500 cc. Erlenmeyer flasks, heat to 90°C. and titrate with the
1 Assoc. Official Agr. Chemists, Methods, 1920, 55.
2 Tbid., 53.
8 Thid., 54.
* Z. anal. Chem., 1893, 32: 415; J. prakt. Chem., 1915, 91: 133.
1922| GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 395
standard bromate solution, using 5 drops of a 0.2% solution of methyl orange as
indicator. The indicator should not be added until near the end of the titration, and
the solution should be agitated continuously in order to avoid local excess of the bromate
solution. The number of cc. of standard bromate solution used represents directly
the total per cent of arsenic in the sample expressed as arsenic oxide.
Modified Gooch and Browning Method.
Weigh an amount of the sample equal to the arsenic oxide equivalent of 100 cc. of
the standard iodine solution, transfer to a 500 cc. Erlenmeyer flask; add 5 cc. of con-
centrated sulfuric acid, dilute to 150-200 cc. and add 1 gram of potassium iodide.
Boil until the volume is reduced to about 40 cc. A glass boiling tube will prevent
superheating and loss of the solution by violent boiling. Cool, dilute to 150-200 cc.,
remove the excess iodine by titration with 0.05N sodium thiosulfate, nearly neutralize
the sulfuric acid with a solution of sodium hydroxide (40 grams in 100 cc. of water)
and finish the neutralization with sodium bicarbonate, adding 4-5 grams in excess and
titrate with standard iodine using starch solution as indicator. The number of cc. of
standard iodine solution used represents directly the total per cent of arsenic in the
sample expressed as arsenic oxide.
Nore.—The boiling tube mentioned above is made from a piece of glass tubing of
about 2 or 3 mm. internal diameter, by sealing it about 1.5 cm. from one end. During
boiling this end is placed in the solution.
ARSENIOUS OXIDE,
REAGENTS.
The reagents used are described under total arsenic, page 394.
DETERMINATION.
Bromate Method.
(Not applicable in presence of nitrates.)
(1) Weigh an amount of the sample equal to the arsenious oxide equivalent of 300 cc.
of the standard bromate solution. Transfer to a 500 cc. Erlenmeyer flask and dissolve
in 100 cc. of hydrochloric acid (1 to 3). Heat to 90°C. and titrate with the standard
bromate solution, using 5 drops of a 0.2% methyl orange solution as indicator.
The number of cc. of bromate solution used, divided by 3, gives the per cent of arsenious
oxide in the sample.
(Applicable in presence of small amounts of nitrates.)
(2) Proceed as in (1) except that the titration is made at room temperature.
CALCIUM OXIDE.
DETERMINATION.
Method 1.—Dissolve 2.0 grams of the sample in 80 cc. of acetic acid (1 to 3), transfer
to a 200 cc. volumetric flask and make to volume. Filter through a dry filter and
transfer a 50 cc. aliquot to a beaker; dilute to 200 cc., heat to boiling and precipitate
the calcium with ammonium oxalate solution. Allow the beaker to stand for 3 hours
on the steam bath, filter and wash with hot water. Dissolve the precipitate in 200 ce.
of water containing 25 cc. of dilute sulfuric acid (1 to 4), heat to about 70°C. and titrate
with standard potassium permanganate solution.
396 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(Not applicable to calcium arsenate containing lead.)
Method 2.—Weigh 2.0 grams of the sample, transfer to a beaker, add 5 cc. of hydro-
bromic acid (sp. gr. 1.31), and 15 cc. of hydrochloric acid (sp. gr. 1.19), and evaporate
to dryness under a hood to remove arsenic; repeat the treatment; add 20 cc. of hydro-
Take up with water and a little hydro-
chloric acid and again evaporate to dryness.
chloric acid, filter into a 200 cc. volumetric flask, wash and make to volume.
TABLE 2.
Trans-
Cooperative results on calcium arsenate containing calcium arsenite.
ANALYST
Percy O’Meara.
Average
J. J.T. Graham.
Average
H. L. Fulmer.
Average
F. L. Hart.
Average.......
L. N. Markovitz.
Average.... wee
G. E. Miller, Bu-
reau of Chem-
istry, Washing-
ton, D. C.
Average.......
TOTAL ARSENIC CALCULATED
AS ARSENIC OXIDE
ARSENIOUS OXIDE
CALCIUM OXIDE
General average
Modified
Official Gooch | Bromate Method Method 2
Distil- | Bromate and Method
lation | Method | Brown- 1
Method ing Hot Cold Titrated | Ignited
Method
percent | percent | percent | percent | percent | percent | percent | per cent
39.96 | 39.67 | 40.65 4.63 4.70 | 29.74 | 29.54
39.92 | 39.77 | 40.65 4.57 4.73 | 29:64] 29:70 | =...
39.94 | 39.72 | 40.65 4.60 4.72 29.69 | 29.62
39.39 | 39.87 | 39.58 4.76 4.76 | 29.60 | 29.60 | 29.48
39.54 | 39.87 | 39.58 4.74 4.76 | 29.60 | 29.60 | 29.76
39.44 | 39.87 | 39.54 4.77 4.76 | 29.48 | 29.54 | 29.84
39.44 | 39.81 | ..... Be oer ote anos EAD ose
39.45 | 39.86 | 39.57 4.76 4.76 | 29.56 | 29.58 | 29.69
= 30.17 | 30.23
é 30.02 | 30.28
es ees ee ee Ee ees
39.56 | 39.52 | 39.82 4.71 4.76 | 29.56 | 29.42 | .....
39.55 | 39.57 | 39.64 4.76 4.78 | 29.49 | 29.48 | .....
39.46 | 39.63 | 39.82 $563 Seite 29.58 | 29.48 | .....
39.51 | 39.57 | 39.55 29.63 | 29.54 |} .....
39.52 | 39.57 | 39.70 | 4.74 4.77 | 29.55 | 29.48
39.40 | 39.69 | 39.21 4.73 4.75 | 30.02 | 29.72 | 29.98
39.45 | 39.53 | 39.33 4.73 4.73 29.86 | 29.68 | 30.18
39.67 | 39.74 | 39.28 4.74 ere 29:90 Serer erent
39.51 | 39.65 | 39.27 | 4.73 4.74 | 29.90 | 29.70 | 30.08
39.61 | 39.43 | 39.61 30.07 | 30.13
39.61 | 39.49 | 39.69 30.28 | 29.97
39.6 39.46 | 39.65 bone SB; 80.18 | 30.05 Ricoh
39.57 | 39.67 | 39.71 4.71 4.75 29.79 | 29.73 | 29.85
1922] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 397
fer a 50 cc. aliquot to a beaker, add 10 cc. of hydrochloric acid and a few drops of nitric
acid; boil and make slightly alkaline with ammonia. Let it stand a few minutes and
filter. Dissolve the precipitate in a little hydrochloric acid, reprecipitate, filter through
the same paper and wash with hot water. To the combined filtrates and washings add
20 ce. of acetic acid (1 to 3) and adjust the volume to about 200 cc. Heat to boiling,
precipitate with ammonium oxalate solution and allow to stand for 3 hours on a steam
bath. Filter and wash with hot water. Ignite and weigh as calcium oxide; or dissolve
the precipitate in 200 ce. of water containing 25 cc. of dilute sulfuric acid (1 to 4), heat
to about 70°C. and titrate with standard potassium permanganate.
DISCUSSION.
The results of the work on calcium arsenate are somewhat at variance, and it is to
be regretted that so few reports have been received. The results for total arsenic by
the bromate method agree very well with the official distillation method and are more
uniform than by the modified Gooch and Browning method. The largest variations
from the mean are found in the results by the modified Gooch and Browning method.
It is recommended that no further work be done on this method.
The results for arsenious oxide by the bromate method are very good and show that
with careful work the accuracy of the method is not affected by the temperature of the
solution, between the limits of room temperature and 90°C.
It is impossible to make this titration in hot solution in the presence of an appreciable
amount of nitrates as the methyl orange is bleached, thus obscuring the end point.
This is not the case, however, when the titration is made at room temperature. The
referee has found that the addition of 0.25 gram of lead nitrate to the titration flask
makes no difference in the results when titrated immediately in the cold, but when
heated the indicator is instantly bleached without the addition of any of the bromate
solution. ‘
The results reported by each analyst for calcium oxide agree very well by the two
methods, but there is some variation among the different analysts. The results of
cooperative tests last year were more nearly uniform, and the referee believes that
both of these methods are worthy of adoption by the association.
Commercial calcium arsenates frequently contain a small amount of lead arsenate,
and in the analysis of such a mixture by Method 2 it is necessary to remove the lead
before precipitating the calcium or the precipitate will be contaminated with lead
oxalate. This is not the case, however, with Method 1, as the lead arsenate is insoluble
in the acetic acid and is separated from the calcium in the preliminary treatment.
GENERAL PROCEDURE FOR THE ANALYSIS OF A PRODUCT CONTAINING ARSENIC, ANTI-
MONY, LEAD, COPPER, ZINC, IRON, CALCIUM, MAGNESIUM, ETC,
(Applicable to such preparations as Bordeaux-lead arsenate, Bordeaux-zinc arsenite,
Bordeaux-Paris green, Bordeaux-calcium arsenate, etc.) i
A sample was prepared by mixing thoroughly 200 grams of Bordeaux mixture, made
from commercial copper sulfate and lime, with 400 grams of commercial lead arsenate
and 200 grams of commercial zinc arsenite. Each material had been passed through a
40 mesh sieve, thoroughly mixed, and analyzed before preparing the composite sample
for cooperative work.
The Bordeaux, analyzed by the official electrolytic method, showed a copper content
of 18.51%; the lead arsenate, analyzed by the official sulfate method, contained 63.67%
of lead oxide; while the zinc arsenite, analyzed by the phosphate method, contained
57.13%, and by the mercury-thiocyanate method, 56.93% of zinc oxide.
The mixture submitted for cooperative work should contain, therefore, 4.63%
of copper, 31.84% of lead oxide and 14.26% of zinc oxide. This differs from the
398 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
sample used in the 1920 work in that the lead oxide content is increased to twice the
amount and the copper content is reduced to approximately one-half.
LEAD OXIDE.
Weigh 1 gram of the powdered sample and transfer to a beaker. Add 5 cc. of hydro-
bromic acid (sp. gr. 1.31), and 15 cc. of hydrochloric acid (sp. gr. 1.19), and evaporate
to dryness to remove arsenic; repeat the treatment; then add 20 cc. of hydrochloric
acid (sp. gr. 1.19), and again evaporate to dryness. Heat the residue to boiling in
25 ec. of 2N hydrochloric acid, filter immediately to remove silica, and wash with hot
water to a volume of 125 cc. Care must be taken to see that all lead chloride is in
solution before filtering. If it will not all dissolve in 25 ce. of the 2N acid add 25 cc.
additional and dilute the filtrate to 250 cc. volume. Pass in hydrogen sulfide until
the precipitation is complete. Filter and wash the precipitate thoroughly with 0.5N
hydrochloric acid saturated with hydrogen sulfide. Save the filtrate and washings for
the determination of zinc. Transfer the filter paper containing the sulfides of lead and
copper to a 400 cc. Pyrex beaker and completely oxidize all organic matter by heating
with 4 cc. of concentrated sulfuric acid, together with a little fuming nitric acid; then
completely remove nitric acid by heating on a hot plate to copious evolution of the
white fumes of sulfuric acid, cool, add 2 or 3 cc. of water and again heat to fuming.
Cool and determine the lead as sulfate as directed for lead arsenate!, beginning with
“Cool, add 50 cc. of water and about 100 cc. of 95% alcohol”. The alcoholic solution
should not stand more than 24 hours before filtering, as the solution may creep up the
sides of the beaker and deposit crystals of copper sulfate which are very difficult to
redissolve in the acid alcohol. From the weight of lead sulfate calculate the amount
of lead oxide present, using the factor 0.73600.
COPPER.
Evaporate the filtrate and washings from the lead sulfate precipitation to fuming,
add a few cc. of fuming nitric acid to destroy organic matter, and continue the evap-
oration until about 3 cc. remain. Determine the copper by Low’s titration method as
directed under Bordeaux mixture’, or by electrolysis as follows:
Take up the sulfuric acid solution with water, add 1 cc. of concentrated nitric acid,
and filter if necessary. Make the volume to about 150 cc. and electrolyze as usual.
ZINC OXIDE.
REAGENT.
Dissolve 27 grams of mercuric chloride and 39 grams of potassium thiocyanate in
1 liter of water. In lieu of the potassium thiocyanate, 30 grams of ammonium thio-
cyanate may be used’.
DETERMINATION.
Concentrate the filtrate and washings from the sulfide precipitation by gentle boiling
to about 50 cc.; continue the evaporation to dryness on a steam bath and dissolve the
residue in 100 ce. of water containing 5 cc. of hydrochloric acid (1 to 1). Add 40 ce.
of the mercury-thiocyanate reagent and stir vigorously until the zinc is precipitated.
Allow to stand for at least an hour with occasional stirring, filter through a tared Gooch
crucible, wash with water containing 20 cc. of the mercury-thiocyanate reagent per
liter, and dry to constant weight at 105°C. From this weight calculate the zine oxide,
using the factor 0.16331.
1 panes: Official Agr. Chemists, Methods, 1920, 58.
3 Thid., 62.
§ Trans. Am. Inst. Mel., 1914, 8: 146; J. Am. Chem. Soc., 1918, 40: 1036.
1922| GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES
TABLE 3.
Cooperative results on Bordeaut—lead arsenate—zine arsenite.
ANALYST
EL. N. Markovitz
General averages... 0c 566.6 ss si
Calculated value..................
G. E. Miller+
LEAD OXIDE
399
COPPER
Electrolytic Titration
Method Method
per cent per cent
4.65
4.61
4.62
4.64
4.63
4.75
4.75
4.75
4.64
4.70
4.67
4.46
4.59
4.66
4.57
4.64
4.64
4.63
4.64
4.64
4.51
4.56
4.54
4.54
4.64 4.61
4.63 4.63
4.64
4.67
4.57
4.63
ZINC OXIDE
per cent
14.29
14.30
14.37
14.32
14.29
14.30
14.27
14.28
14.34
14.33
14.28
14.31
14.32
14.28
14.36
14.30
14.34
14.32
14.31
14.26
14.23
14.21
14.30
14.25
*Not included in the general average.
tReceived too late for tabulation.
400 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No 3.
Nore.—Some iron is generally present and during the zinc determination it should
be in the ferrous condition. In making the sulfide precipitation the hydrogen sulfide
should be passed into the solution for a sufficient time to reduce the iron, in addition
to precipitating the copper and lead. The zinc-mercury-thiocyanate precipitate
normally is white, and it should not contain occluded ferric thiocyanate sufficient to
give it more than a faint pink color.
DISCUSSION.
The first three reports received on this sample showed the need of a slight modifi-
cation in the method for zinc oxide. The results were from 0.5 to 3.0% below
the value for zinc oxide calculated from the analysis of the zinc arsenite in the sample.
Percy O’Meara reported difficulty in obtaining a precipitate. This difficulty was
evidently caused by a solvent action of the ammonium chloride formed by the neutral-
ization of the hydrochloric acid in the filtrate from the hydrogen sulfide precipitation.
Experiments were then conducted with the view of modifying the method to eliminate
this error. Substitution of sodium hydroxide for the ammonium hydroxide as the
neutralizing agent produced somewhat better results. However, by carrying the
evaporation to dryness all of the acid was expelled thereby avoiding the presence of
salts due to its neutralization. With this modification results were obtained which
agreed with the calculated value.
The method as modified was sent at once to all of the cooperators who had not
reported, and all results for zinc oxide shown in Table 3 were obtained by following these
modified directions. Examination of Table 3 shows that these results are very good,
there being a maximum yariation of only 0.1% among four analysts, while the
general average of all their results varies only 0.05% from the calculated value.
The results for copper are also good and check the calculated value for copper. The
results for lead oxide with one exception agree and check with the calculated value.
The one exception may have been due to the vagueness of the method as sent out, in
regard to the amount of sulfuric acid to use in digesting the sulfides of copper and lead.
This vagueness has been corrected, and the method as given in this report specifies the
use of a definite quantity.
LONDON PURPLE.
Very little work was done during 1921 on London purple. The 1920 sample was
analyzed by one chemist whose results are given in the following table:
TABLE 4.
Total arsenic calculated as arsenious oxide.
ZINC OXIDE
OFFICIAL IODINE DISTILLATION
ANALYST SODIUM CARBONATB
METHOD* METHODt
METHOD
per cent per cent per cent
M. Harris, Bureau of Chemistry, 29.73 30.02 30.10
Washington, D. C. 29.85 30.18 29.85
at 29.94 29.93
ASVETARC ic. ote este tres cette eistere 29.79 30.05 29.96
General average 1920............ 29.54 29.65 29.70
*Assoc. Official Agr. Chemists, Methods, 1920, 56.
tIbid., 54.
tJ. Assoc. Official Agr. Chemists, 1921, 4: 397.
1922] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 401
These results agree fairly well with those reported last year. The methods with
the exception of the distillation method were also tested by the referee in 1919! with
satisfactory results.
PARIS GREEN.
No cooperative work was done during 1921 on Paris green. The
results for arsenious oxide by the bromate method given in the 1919
and 1920 reports were very good. The referee recommends this method
for final adoption by the association.
MAGNESIUM ARSENATE.
The referee has considered methods for the determination of mag-
nesium in magnesium arsenate. Since most commercial magnesium
arsenate contains some calcium compounds the problem is presented
of separating a small amount of calcium from a much larger quantity
of magnesium. The ordinary method of separation by means of am-
monium oxalate can not be used since, under these conditions, mag-
nesium is precipitated along with the calcium. Hillebrand? recommends
the modified Stolberg? method for the separation of small amounts of
calcium from large quantities of magnesium. The referee has adapted
this method to the determination of calcium and magnesium in mag-
nesium arsenate. Very satisfactory results have been obtained by the
following procedure:
Weigh 2.0 grams of the sample, transfer to a Pyrex beaker and evaporate twice with
a mixture of 5 cc. of hydrobromic acid (sp. gr. 1.31), and 15 cc. of hydrochloric acid
(sp. gr. 1.19). Add 25 ce. of sulfuric acid (1 to 4), and evaporate to copious evolution
of sulfuric acid fumes. Oxidize any organic matter with a few drops of fuming nitric
acid and continue the evaporation to dryness on a hot plate. Cool and add 3 ce. of
water. Heat until the magnesium sulfate is all in solution, adding a few more drops
of water if necessary. This should make a nearly saturated solution. Cool and add
100 ce. of methyl-ethyl alcohol mixture (90 cc. of methyl and 10 ce. of ethyl), stir, and
let stand for 1 hour. Filter and wash with the methyl-ethyl alcohol mixture. All of
the calcium sulfate will be in the residue and the magnesium sulfate in the filtrate.
Dissolve the residue in hot water and a little dilute hydrochloric acid, neutralize
with ammonia and add sufficient acetic acid to make the solution contain about 2%;
heat to boiling and precipitate the calcium with ammonium oxalate solution.
Allow to stand 3 hours on a steam bath, filter and wash with hot water. Dissolve in
200 ce. of water containing 25 cc. (1 to 4) sulfuric acid, heat to 70°C. and titrate with
standard permanganate solution. From this titration calculate the per cent of calcium
oxide in the sample.
Evaporate the alcoholic filtrate to dryness, dissolve in water and a little hydrochloric
acid and make to a volume of 200 cc. Transfer a 50 cc. aliquot to a beaker, add 5 ce.
of hydrochloric acid and dilute to about 100 cc. Add 10 cc. of a 10% solution
of ammonium phosphate and make iust alkaline with ammonia; after standing 10 or
1 J. Assoc. Official Agr. Chemists, 1921, 4: 397.
2U.S. Geol. Sur., Bull. 700, 143.
* Zeit. angew. Chem., 1903, 17: 769.
402 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
15 minutes, add 15 or 20 cc. of strong ammonia and allow to stand at least 4 hours.
Filter, wash with ammonia water (1 to 10), ignite and weigh as magnesium pyro-
phosphate.
In view of the fact that at present there is very little, if any, mag-
nesium arsenate on the market, the association is hardly justified in
continuing this work.
SUGGESTIONS FOR FUTURE WORK.
It has been noticed by the referee and other chemists in the Insecti-
cide and Fungicide Laboratory of the Bureau of Chemistry that oc-
casionally the official distillation method for total arsenic gives erratic
results, and in all cases these results are low when compared with those
by the Gooch and Browning method.
Graham and Smith! have shown that the presence of nitrates or
nitrites in the sample will cause the official distillation method to give
low results, especially when some time is allowed to elapse between the
distillation and the titration of the distillate. It is suggested that this
effect may be due to the slow oxidation of arsenic in the distillate by
nitrosyl chloride resulting from the interaction of the nitrates or nitrites
with hydrochloric acid.
They have shown that a modification of the method of Jannasch and
Seidel? will give accurate results in the presence of a considerable quan-
tity of nitrates. In this method the procedure is the same as in the
official distillation method, except that hydrazine sulfate and sodium
bromide are used as the reducing agents, and a smaller quantity of
hydrochloric acid is used in the distillation.
Since small amounts of nitrates are very frequently present in insecti-
cides, it is important that the association take steps at once to so modify
the present official distillation method as to provide for this condition.
The following procedure is recommended by Graham and Smith:
REAGENTS.
(a) Starch indicator—Prepare as directed under Paris green®.
(b) Standard arsenious ozide solution —Prepare as directed under Paris green‘.
(c) Standard iodine solution.—Prepare as directed under Paris green*.
(d) Standard bromate solution.—Prepare as directed under zinc arsenite, page 392.
(e@) Hydrazine sulfate and sodium bromide solution Dissolve 20 grams of hydrazine
sulfate and 20 grams of sodium bromide in 1 liter of dilute (1 to 4) hydrochloric acid.
DETERMINATION.
Weigh an amount of the sample containing not more than 0.4 gram of metallic arsenic
and transfer to a distilling flask. Add 50 cc. of the hydrazine sulfate and sodium
bromide solution and close the flask with a stopper through which passes the stem of
1J. Ind. Eng. Chem., 1922, 14: 207.
2 J. prakt. Chem., 1915, 91: 133.
5 Assoc. Official Agr. Chemists, Methods, 1920, 53.
1922] GRAHAM: REPORT ON INSECTICIDES AND FUNGICIDES 403
a dropping funnel. Connect to a well cooled condenser, the delivery end of which is
attached to the system of flasks used in the official distillation method, omitting the
third flask. Boil for 2 or 3 minutes and then add 100 cc. of concentrated hydrochloric
acid by means of the dropping funnel and distil until the volume in the distilling flask
is reduced to about 40 cc.; add an additional 50 cc. of concentrated hydrochloric acid
and continue the distillation until the contents of the flask are again reduced to about
40 ec. Wash down the condenser, transfer the contents of the receiving flasks to a
1 liter graduated flask, make to volume and mix thoroughly. Pipet a 200 cc. aliquot to
a 500 cc. Erlenmeyer flask, nearly neutralize with sodium hydroxide, finish the neutral-
ization with sodium bicarbonate, add 4-5 grams in excess and titrate with standard
iodine solution using starch solution as indicator; or to the 200 cc. aliquot add 10 ce.
of concentrated hydrochloric acid and titrate with the standard bromate solution as
described under zinc arsenite, page 392.
This method has been thoroughly tested in the Insecticide and Fungi-
cide Laboratory of the Bureau of Chemistry on a large number of samples.
In all cases the results were very satisfactory, and the method is now
used for the analysis of all samples containing nitrates.
In view of the foregoing facts, the referee suggests the adoption of
this method at once as a tentative method, and that it be studied fur-
ther with a view to its adoption as an official method after it has been
tested by cooperative work.
RECOMMENDATIONS.
It is recommended—
(1) That the mercury-thiocyanate method for zine oxide in zinc
arsenite, page 392, be adopted as an official method. (Adopted as a
tentative method in 1920.)
(2) That the bromate method, procedures (1) and (2), for the deter-
mination of arsenious oxide in zinc arsenite, page 394, be adopted as an
official method.
(3) That the official method for the determination of water-soluble
arsenic in lead arsenate! be adopted as official for the determination of
water-soluble arsenic in zine arsenite.
(4) That the bromate method, page 394, be adopted as an official
method for the titration of the acid distillate in the official distillation
method for the determination of total arsenic.
(5) That no further study be made of the modified Gooch and Brown-
ing method, page 395, for the determination of total arsenic in calcium
arsenate.
(6) That the bromate method, procedures (1) and (2), for the deter-
mination of arsenious oxide in calcium arsenate, page 395, be adopted as
an official method.
(7) That method (1), page 395, for the determination of calcium
1 Assoc. Official Agr. Chemists, Methods, 1920, 59.
404 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
oxide in calcium arsenate be adopted as an official method. (Adopted
as a tentative method in 1920.)
(8) That method (2), page 396, for the determination of calcium oxide
in calcium arsenate be adopted as an official method. (Adopted as a
tentative method in 1920.)
(9) That in the “General procedure for the analysis of a product
containing arsenic, antimony, lead, copper, zinc, iron, calcium, mag-
nesium, etc.,” page 398, the methods for lead oxide and copper be adopted
as official methods.
(10) That in the “General procedure for the analysis of a product
containing arsenic, antimony, lead, copper, zinc, iron, calcium, mag-
nesium, etc.,” page 398, the method for zinc oxide be adopted as an
official method. (Adopted as a tentative method in 1920.)
(11) That further action on the official distillation method for the
determination of total arsenic in London purple be deferred until the
suggested modification, page 402, has been studied.
(12) That the zinc oxide-sodium carbonate method be adopted as an
official method for the determination of total arsenic in London purple.
(13) That the bromate method, procedures (1) and (2), for the deter-
mination of arsenious oxide in Paris green, as given in the referee’s report
in 1920, be adopted as an official method.
(14) That no further work be done at this time on magnesium arse-
nate.
(15) That the words ‘‘Not applicable in presence of nitrates’? be
placed over the present distillation method for total arsenic wherever
it occurs among the methods of the association.
(16) That the distillation method for total arsenic in the presence of
nitrates, page 402, suggested by Graham and Smith be adopted as a
tentative method, with a view to its adoption as an official method after
it has been further tested by cooperative work.
(17) That the work on insecticides and fungicides for 1922 be a study
of the distillation method mentioned in Recommendation 16 for the
determination of arsenic in the presence of nitrates.
1922] MACINTIRE: REPORT ON SOILS 405
REPORT ON SOILS.
By W. H. MacIntire (Agricultural Experiment Station, Knoxville,
Tenn.), Referee.
Your referee made an attempt to evolve a rapid and dependable
method for the determination of the total sulfur in soils. Considerable
preliminary work was done by the referee alone, after which a number
of procedures were drafted and sent out to thirty of those from whom
collaboration was expected. Though some of the procedures were con-
sidered inexact, they were incorporated in the outline in order that the
referee’s findings might be confirmed, since they included principles of
technique which have been used in determining sulfates.
In the preliminary work, the original soil in each case was run in
parallel with the same soil which had been fortitied with either sodium,
calcium or magnesium sulfate, in order to ascertain whether an accu-
mulation of sulfates derived from the preliminary oxidative process
could be recovered from the soil mass.
The preliminary work of the referee may be concisely given as follows:
(1) Charges of 10 grams each of five unfortified soils were incinerated with 10 grams
of magnesium nitrate, and the mass was lixiviated and leached with distilled water.
Concordant results could not be secured.
(2) A 25-gram charge of one soil was incinerated with 10 grams of ammonium nitrate.
The residue was pestled and digested, and then leached through a Biichner funnel with
water, hydrochloric acid (1 plus 9), nitric acid (1 plus 9) and acetic acid (1 plus 9).
Both the water extract and the acetic acid extract yielded sulfate recoveries far in
excess (about six times) of the recoveries given by the hydrochloric and nitric acid
digestions and extractions of both native and fortified soils. The iron carried by the
acid solutions was removed as insoluble oxides by evaporation to dryness and ignition
upon an electric hot plate, after the addition of an excess of a base to hold the sulfate
radicle. It afterwards appeared that the high heat necessary to convert all iron salts
into insoluble oxides caused dissociation of the sulfate.
(3) Ten-gram charges of each of three soils were fused with a mixture of 15 grams of
sodium carbonate and 5 grams of potassium carbonate, extracted with water and
filtered. The residues were then extracted with hydrochloric acid in order to dissolve
any barium carbonate. Dilute sulfuric acid added to these acid extracts yielded
0.006, 0.0038 and 0.0019 gram of barium sulfate, indicating that barium occurrences
could not account for any appreciable part of the unrecovered added sulfate.
(4) Twenty-five-gram charges of each of four soils were incinerated with 25 grams
of sodium peroxide. The residues were extracted with water or concentrated hydro-
chloric acid. The extracted residue was then dehydrated and again leached with water
or hydrochloric acid. In no case did this procedure result in a recovery equivalent to
the blank of the original soil plus the added sulfate. The recovery in each instance
was considerably greater with the water extraction than with the hydrochloric acid
extraction, in one instance about 25 times.
(5) Several soils were digested separately with a mixture of hydrochloric, nitric and
hydrofluoric acid and with nitro-hydrofluoric acid. Great difficulty was experienced
in removing all of the fluorine, resulting in contamination of the barium sulfate pre-
cipitates with barium fluoride.
406 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
(6) Twenty-gram charges of each of three soils were digested with 20 cc. of hydro-
fluoric acid and 25 cc. of nitric acid and filtered. The acid solutions were then evap-
orated and the siliceous residue ignited with magnesium nitrate. After ignition with
magnesium nitrate the residues were subjected to separate extractions with water,
hydrochloric acid and acetic acid, and the second extractions added to the respective
initial acid extractions. The contaminative influence of barium fluoride previously
noted was again experienced.
(7) Twenty-five-gram charges of each of three soils, both native and fortified, were
ignited with magnesium nitrate and subjected to separate extractions with water,
hydrochloric acid and acetic acid. In the case of one soil, the three solvents gave
sulfate extractions which were about equivalent, while with the other two soils, the
hydrochloric and acetic acid extractions were greater than those secured by water; all,
however, were below the amount of sulfate added.
(8) The J. Lawrence Smith procedure, preceded by incineration with magnesium
nitrate, was tried upon each of three soils, using 25-gram charges. After drying and
heating the soil with a mixture of 5 grams of magnesium oxide and 11.5 cc. of nitric acid,
a disintegration was effected by ignition of the residue with a mixture of 2 grams of
ammonium chloride and 10 grams of calcium carbonate. The ignited residue was then
boiled with distilled water, ammonium carbonate and bromine; filtered; concentrated
to 400 ce., and barium sulfate determined. In this procedure, results secured upon the
native soil were higher than those obtained by any of the other procedures; however,
the recovery of added sulfates in the same three soils which had been fortified was in
no case equivalent to the theoretical or expected recovery. It appears probable that
the fault lay in the excessive heat utilized in the preliminary oxidation with magnesium
nitrate in the electric furnace.
(9) Twenty grams of soil mixed with magnesium oxide and nitric acid, using a slight
excess of magnesium oxide, were evaporated to dryness on an electric hot plate and then
heated in an electric furnace. The incinerated mass was pestled and extracted with
(1) water and (2) acetic acid. Five and four-tenths and 7.5 milligrams of barium
sulfate were obtained, respectively. With added calcium sulfate equivalent to 0.1033
gram of barium sulfate, only 0.0388 gram and 0.0781 gram of barium sulfate were
obtained by water and acetic acid, respectively, with digestions of thirty minutes at
boiling temperature.
(10) Twenty-five-gram charges evaporated with a solution of 10 grams of ammonium
nitrate on an electric hot plate, heated in an electric furnace, and the residue boiled
thirty minutes with an excess of acetic acid, gave a recovery of 0.0895 gram of barium
sulfate from soil plus sodium sulfate equivalent to 0.1033 gram of barium sulfate; while
only 0.0836 gram of barium sulfate was recovered from the same soil, fortified with
potassium sulfate of the same barium sulfate equivalence. A corresponding addition
of SO,, as magnesium sulfate, gave a recovery of but 0.0249 gram of barium sulfate
for the fortified soil.
(11) Twenty-five grams of soil, fortified with 0.1033 gram of barium sulfate equiva-
lent were boiled 1 hour with 150 ce. of nitric acid and filtered. The insoluble residue
was then boiled with nitric acid (1 plus 9) containing 0.2500 gram of magnesium oxide
and filtered. The combined filtrates were evaporated and heated, and the insoluble
oxides boiled with acetic acid and removed by filtration. The total barium sulfate
recovery from the fortified soil was only 0.0073 gram. The same treatment applied
to a charge fortified with sodium sulfate equivalent to 0.1033 gram of barium sulfate
gave only 0.0189 gram of barium sulfate.
As a result of the foregoing and additional preliminary work, six different procedures
were sent to each of thirty collaborators, in order to ascertain whether the preliminary
1922] MACINTIRE: REPORT ON SOILS 407
findings in the referee’s laboratory were to be found with other types of soil. Pro-
cedure VI was not carried out by any of the collaborators because of the inability to
secure calcium peroxide.
REFEREE’S OUTLINE OF PROCEDURES FOR COLLABORATORS.
Sandy soils and other soils low in organic matter__________ 50 grams.
Charges Loams, peats and soils high in organic matter____________ 25 grams.
Run one Joam or clay loam and one soil of local interest by each procedure. In
addition, fortify a charge of each soil with an aliquot of calcium sulfate or magnesium
sulfate solution (preferably both) sufficient to give a precipitate of 0.2000 gram of
barium sulfate, and compare the addition to the determined recovery from the fortified
soil, minus that from the soil unfortified. Make all barium sulfate precipitations from
a volume of about 200 cc. at boiling temperature, with slow addition of barium chloride
and vigorous agitation. Permit the barium sulfate precipitate to stand in a warm
place for 18 hours. Determine and apply the reagent blanks. Filter all barium
sulfate precipitates upon an acid-washed asbestos filter in a platinum or Vitreosil cru-
cible. Place the Gooch in a porcelain crucible and heat moderately for 10 minutes.
I. Peroride combustion.—(a) Mix an air-dry charge of soil with 25 grams of sodium
peroxide and then introduce sufficient water to insure a well-mixed thick paste. Trans-
fer to a nickel or other suitable crucible and heat in the electric furnace for a full hour
after expulsion of moisture at the extreme heat of the furnace. Remove incinerated
mass by mechanical means; pulverize and transfer to a 500 cc. graduated flask (or
liter flask, if need be). Add about 100 cc. of water and a few drops of bromine. Dis-
solve the alkali and add an excess of 25 cc. of hydrochloric acid (1 to 1). Boil for an
hour, maintaining a volume of about 300 cc.; cool and make to volume. Pour off on
a 9cm. Biichner filter the supernatant liquid and the necessary fraction of the sus-
pended matter to secure an aliquot of one-half the volume of the flask. Evaporate the
filtrated aliquot to dryness. Take up with 10 cc. of hydrochloric acid (1 plus 9); remove
silica along with iron by ammonia, electrolysis or conversion to insoluble oxide, as may
be most feasible, and dissolve with acetic acid. (It is essential that the iron be
removed.) Precipitate the barium sulfate in the manner prescribed and from the volume
previously designated.
(b) Proceed as in (a) up to the point where the 1 to 1 solution of hydrochloric acid
is added. Instead of acid, add distilled water and boil; filter; wash; acidulate the
filtrate; remoye the silica and determine the barium sulfate.
II. Magnesium nitrate combustion—(a) Mix the charge with a saturated, slightly
alkaline solution of magnesium nitrate to a thick workable paste. Dry and heat in
the electric furnace for an hour after expulsion of water.. Transfer the ignited residue
to a 500 cc. Pyrex beaker. Add 300 cc. of distilled water; introduce a few drops of
bromine and boil for 1 hour over sulfur-free heat. Throw the hot mixture on a 9 cm.
Biichner filter and wash with hot water to filtrate volume of 1 liter. Concentrate to
400 cc. and precipitate the barium sulfate.
(b) Proceed as in (a) up to the point of boiling with distilled water. Instead of
water, add an excess of acetic acid and boil for 1 hour. Filter; wash the precipitate
with hot water to a filtrate volume of 1 liter. Concentrate filtrate to 400 cc. and pre-
cipitate barium sulfate.
(c) Proceed as in (a) up to the point of boiling with distilled water. Add an excess
of hydrochloric acid and boil for 1 hour. Filter through a 9 cm. Biichner filter and
wash the precipitate with hot water to a filtrate volume of 1 liter. Evaporate to dry-
ness; dehydrate and remove the silica. Take up and remove iron. (See appended
note.) Precipitate the barium sulfate.
408 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Ill. Aqua regia digestion.—Introduce the charge into a 500 cc. Kjeldahl round-
bottom flask. Add 50 cc. of concentrated nitric acid and then 100 cc. of concentrated
hydrochloric acid. Introduce a small funnel into the neck of the flask. Clamp the
flask in an upright position and boil gently for 1 hour. Cool; dilute to 400 cc. and
filter through a double No. 2 Whatman filter on a Biichner funnel, leading into a 1-liter
Pyrex beaker placed under a filtration bell jar. Wash the precipitate with hot water
to a filtrate volume of 1 liter. If the soil is not rich in basic materials, add 0.5 gram of
C. P. magnesium oxide to the acid filtrate and evaporate to dryness. Convert the
ferric salts to oxides and remove both silica and iron as directed in the appended note.
Evaporate to remove the excess of acetic acid used in taking up the ignited residue.
Add 10 cc. of concentrated hydrochloric acid and again evaporate. Take up with 1
or 2 drops of hydrochloric acid and precipitate the barium sodium from a volume of
400 cc., as previously directed.
IV. Nitric acid digestion—lIntroduce the charge into a 500 cc. Kjeldahl flask as in
Procedure III. Add 150 cc. of concentrated nitric acid. Then boil and filter as in
Procedure III. After the removal of the iron and the evaporation of the excess of
acetic acid, take up with concentrated hydrochloric acid and evaporate once more in
order to remove all nitrates before the precipitation of the barium sulfate.
VY. Magnesium nitrate-calcium carbonate-ammonium chloride combustion.—To the soil
charge add 5 grams of C. P. magnesium oxide and mix thoroughly in a platinum dish.
Add 11.5 cc. of concentrated nitric acid in fractions, stirring with a small glass rod.
Dry carefully with non-sulfur heat. Ignite in an electric furnace. Cool and mix the
ignited residue with a pulverized mixture of 10 grams of pulverulent calcium carbonate
and 2 grams of ammonium chloride. Heat in an electric furnace, continuing the heat
for a period of 1 hour after the furnace has reached its maximum temperature. Cool;
slake the lime and transfer the mass to a 600 cc. Pyrex beaker, pestling or policing and
washing the fraction clinging to the side of the dish (using a few drops of acetic or hydro-
chloric acid, if need be) into the beaker. Add 400 ce. of distilled water and 15 grams of
ammonium oxalate and a few drops of bromine. Heat on a sulfur-free heat to boiling
for 1 hour. While hot, filter through a 9 cm. Biichner funnel and wash with hot water
to a volume of 1.5 liters. Concentrate the filtrate to about 400 cc.; acidify with a slight
excess of hydrochloric acid, and precipitate the barium sulfate as previously prescribed,
being sure to agitate vigorously during the addition of barium chloride.
VI. Calcium peroxide combustion.—To the soil charge add and thoroughly mix 12.5
grams of powdered calcium peroxide (37.5 grams of CaO,.8 H.O). Heat slowly and
then for an hour at full heat of an electric furnace. Cool; slake and continue as above
under Procedure V, with reference to the treatment of the ignited residue.
Eyaporate the acid solution in the 1-liter Pyrex beaker and heat till no trace of acid
fumes can be detected. Allow the beaker to cool; add 10 cc. of acetic acid and 150 ce.
of water; and boil for 15 minutes. Filter the granular, insoluble oxides on a small
Biichner or Hirsh filter, washing with hot water. Add 10 cc. of concentrated hydro-
chloric acid to the filtrate, and evaporate off the acetic acid. Add 10 cc. of hydro-
chloric acid and repeat the evaporation; take up with a few drops of hydrochloric acid
and hot water and filter off any silica present.
Nore.—The iron in the nitric acid and hydrochloric-nitric acid solutions may be
removed by insuring the presence of sufficient base to hold the sulfate radicle and then
converting the ferric salts to insoluble oxides, thereby eliminating an excess of am-
monium salts and the necessity of handling the ammoniacally precipitated hydrated
oxide.
1922] MACINTIRE: REPORT ON SOILS 409
For convenience in consulting the tables the following index to the procedures is
given:
Procedure 1. Peroxide combustion.
(a) hydrochloric acid extraction.
(b) water extraction.
Procedure II. Magnesium nitrate combustion.
(a) water extraction.
(b) acetic acid extraction.
(c) hydrochloric acid extraction.
Procedure III. Agua regia digestion.
Procedure [V. Nitric acid digestion.
Procedure V. Magnesium niirate-calcium carbonate-ammonium chloride combustion.
Procedure VI. Calcium peroride combustion.
TABLE 1.
Comparison of methods for determination of sulfur.
(Analyst, Charles Reeder)
A Barium
Barium Barium | Barium | Barium Sulfate
Soil Sulfate Sulfate | Sulfate | Sulfate Tron in 12.5 Sulfur
Added* Soi Recovered |Recovered | Removed | Grams of
oil Soil
gs. mgs. mgs. mgs. per cent mgs. per cent
12.5¢
; 16.1¢t No 16.1 0.0178
10.57
15.7tt No 18.7 0.0205
10.5t 118.5
15.7tt 106.3 89.7 No
12.5t Yes
19.67 19.6 0.0215
12.5t Yes
19.5tt 19.5 0.0214
6.5f 84.7 Yes
410 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Procepvure II.
25t 8.5
6.7 7.6 3.8
25§ 31.4
32.8 By | 16.1
12 21.6
21.1 21.3 22.1
12 135 154.6
154.2 21.3 133.1 98.7
12 2.4
PUSS 2.6 2.7
12 135 113.4
29.7 2.6
12 1.0
2.0 1.5
12 57.1
84.7 1.5
ProcepureE III.
12% 15.4
15:2 15.3TT 16.0 0.0175
12** 135 149.6
149.9 15.3tt | 184.5 99.8
12s 16.2
15.8 16.0Tt 16.7 0.0184
iP pee: 135 149.3
151.0 16.0t¢ | 184.2 99.7
Procepunre V.
15t 12.7
12.4 12.5 10.4 0.0115
15t 169 128.3
129.0 12.5 116.2 68.8
12+ 4.4
10.7 Yes
12t 135 100.8
34.8
12t 20.3 No
PAN sila | PANY No 21.5 0.0236
12t 154.4 No
155.9 20.7 134.5 99.9 No
*Equivalent from calcium sulfate added.
tHydrochloric acid extraction.
{Water extraction only.
Acetic acid extraction.
*A qua regia extraction.
ttAverage.
1922] MACINTIRE: REPORT ON SOILS 411
TABLE 2.
Comparison of methods for determination of sulfur (expressed as sulfur trioxide).
(Analyst, S. Lomanitz)
Procedure I Procedure II
Soil 7 7 . L. Smith Calci
Number | rtuction) | Extraction) | O0UweTY | “Modifed’ | ‘Nitrates
per cent per cent per cent per cent per cent
5954 0.128 0.001 0.060 0.082 ae
1956 0.032 0.002 0.013 0.025 0.053
18910 0.064 0.006 0.020 0.050 0.035
18911 0.054 0.010 0.022 0.121 0.045
18999 0.055 0.029 0.011 0.004 0.067
19000 0.032 0.027 0.007 0.073 0.067
TABLE 2 (Continued).
Calcium sulfate recovered from barium sulfate equivalent additions*.
Soil Calcium Calcium Calcium Calcium
Number Sulfatet Sulfatet Sulfatet Sulfatet
gram gram gram gram
5954 0.0610 0.0250 0.1200 0.0625
1956 0.1350 0.1340 0.1830 0.0720
18910 0.1350 0.1080 0.1740 0.1175
18911 0.0825 0.1230 0.1360 Meee
18999 0.0915 0.1235 0.1225 0.1110
19000 0.1225 0.0850 0.1200 0.0625
*After applying respective blanks from soil.
tAdded 0.1340 gram of calcium sulfate.
tAdded 0.1883 gram of calcium sulfate.
TABLE 3.
Comparison of methods for determination of sulfur (expressed as barium sulfate).
(Analyst, A, L. Prince)
Plat Procedure I Procedure II Procedure III Procedure IV
gram gram gram gram
11B OOF TE I ov cysieyai sys 0.0120* 0.0072*
11A 0.07927 0.0396 + 0.04447 0.0501 f
*Corrected for blank and obtained from 10-gram sample.
tOne determination.
412 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
TABLE 4.
Comparison of methods for determination of sulfur (expressed as sulfur).
(Analyst, V. H. Morris)
> Procepune I Procepune II Pro- Pao Pro-
N aK pee eee eee CEDURE | CEDURE | CEDURE
(nes Ill IV Vv
(a) (b) (a) (b) (c)
per cent per cent per cent per cent per cent per cent per cent per cent
ike 0.0127 | 0.0106 | 0.0105 | 0.0123 | 0.0115 | 0.0061 | 0.0089 | 0.0138
If 0.0382 | 0.0461 | 0.0605 | 0.0647 | 0.0641 | 0.0424 | 0.0400 | 0.0487
2t 0.0441 | 0.0215 | 0.0195 | 0.0119 | 0.0135 | 0.0049 | 0.0411 | 0.0432
2t 0.1263 | 0.0741 | 0.1229 | 0.1196 | 0.1222 | 0.0684 | 0.1400 | 0.1439
*Soil No. 1 is a Volusia silt loam low in organic matter.
tMagnesium sulfate equivalent to 0.1940 gram of barium sulfate was used to fortify these soils. The
amount of sulfur which should have been obtained from Soil No. 1, fortified, is equal to 0.0659 per cent
sulfur; Soil No. 2 is 0.1506 per cent sulfur.
tSoil No. 2 is a sample of Clyde clay relatively high in organic matter.
TABLE 5.
Comparison of methods for determination of sulfur (expressed as barium sulfate).
(Analyst, W. M. Shaw)
Procepure IIT Procepuze III ProcepureE IV PROCEDURE V
Som anp TREATMENT (Modified) (Modified)
gram gram gram gram
Soil only* 0.0049} 0.0283 0.0325). |) Agseer
0.0095§ 0.0303 O:0800;, |} <dsrae
O.OL47A Stk. sc See 0:0285;, || sean
Average 0.0097 0.0293 01038038 ||| ape
Soil plus 0.0405f 0.1635 0.1649 0.0815**
magnesium 0.0109§ 0.1550 0.1530 0.1770F+
sulfate t 0.0387 0.1560 “ayy jim) ageceat eet ght eee
Average 0.0300 0.1582 O:1590! (* Sire eras
Theoretical 0.1387 0.1583 0.1593 0.1223
*Charge of 25 grams.
{Racnalent to 0.1290 gram of barium sulfate.
Iron removed by heating salts to convert into oxides.
§Iron removed by double precipitation with ammonium hydroxide.
Minimum of 7 determinations.
ttMaximum of 7 determinations.
TABLE 6.
Recovery of precipitated barium sulfate from a concentrated nitric acid digestion*.
Digestion of 0.1290 gram of barium sulfale only.
gram gram gram
Residual from acid digestion..............++.00005 0.0700 0.0515 0.0394
Reprecipitated from filtrate. ................000e- 0.0400 0.0485 0.0634
Redissolved in dilute hydrochloric acid. ........... 0.0105 0.0150 0.0171
Digestion of 0.1290 gram of barium sulfate plus 25 grams of soil.
0.0450 0.0426 0.0425
Binal Tecoveny rosie ticsseaaysteoterspelle rats ets rete leys 1 herons
Same'\from/soilfonl yas seems cette eli cies yes seat 0.0325 0.0300 0.0285
Recovery due to barium sulfate addition........... 0.0125 0.0126 0.0140
*Iron eliminated by double ammoniacal precipitation.
EE 0 a ee Aaa eet —_
ee 2
é
1922] MACINTIRE: REPORT ON SOILS 413
COMMENTS BY ANALYSTS.
Charles Reeder, Oregon Agricultural Experiment Staltion—The modifications in the
methods of procedure indicated in the following paragraphs were found to be necessary.
We found time for work with but one soil, Willamette silt loam.
Although Procedure I (a) is cumbersome and time-consuming because of the large
volume of washing from the iron precipitate, we are inclined to think it is by all odds
the most reliable of the several proposed. For some reason, not yet understood, we
could not get satisfactory results from Procedure II (c) (iron removed) or from Pro-
cedure V (with iron removed). Determinations by the same procedure with iron not
removed are too high because of contamination with iron. Our filtrations were through
asbestos fiber in porcelain, not Vitreosil crucibles. Details of the changes in the methods
of procedure are indicated in the following paragraphs:
I: (a) 40 grams of sodium peroxide. Mix the sodium peroxide with moistened soil,
as this prevents loss of soil with the escaping gases. Use centrifuge instead of Biich-
ner; remove iron by ammonium hydroxide. (b) Changes as above except removal of
iron.
II: (a) No change. (b) No change. (c) Instead of washing precipitate to volume
of 1 liter make up to 1 liter; use centrifuge on aliquot. Nemove iron with ammonium
hydroxide.
III: Start the reaction of the acid on the soil slowly, using hot water, then a very
low flame. Make to volume; take aliquot, using centrifuge. Remove iron by am-
monium hydroxide.
V: Use a solution of magnesium nitrate.
G. S. Fraps, Teras Agricultural Experiment Station —I regret that this report is not
as satisfactory as we would desire for the reason that we were able to make only single
determinations. While Mr. Lomanitz is an experienced analyst, some experience
with the methods to be studied is also desirable. The recovery of an added sulfate
was not satisfactory with any of the methods. To judge from the results of analysis,
Procedure V was the most satisfactory of those tested. I have made regular deter-
mination of sulfur on these samples by the calcium nitrate method. Procedure II (a)
was not satisfactory, as you can see by the figures. Procedure I (b), involving the use
of sodium peroxide, is very long and tedious.
A. L. Prince, New Jersey Agricultural Experiment Station.—As the time which could
be devoted to this work was limited, only a few determinations were made. The
lack of an electric furnace precluded attempting some of the methods. However, the
peroxide combustion and magnesium nitrate methods were tried out, using simply the
full heat of the Bunsen burner.
In the determination 11 B, Table 3, the soil was derived from a plot treated with
ammonium sulfate and lime, while 11 A was a soil from a plot treated with ammonium
sulfate and no lime. ‘ :
The peroxide method gave much higher results than aqua regia and nitric acid oxida-
tions, even after subtracting the blank from the sulfur contained in the peroxide. In
all of these methods, the iron was removed by means of ammonia. In the aqua regia
and nitric acid methods, the digestion was carried out for 1 hour, the mixture cooled
and filtered at once. In all cases, the barium sulfate precipitate was collected on an
asbestos filter in a porcelain Gooch crucible.
The same methods were employed on soil 11 A and the magnesium nitrate method
(c) was also tried out without use of the electric furnace. The results were higher on
this soil, as would be expected. The peroxide determination, as in the case of 11 B,
gave much higher results than the other methods. In the nitric acid oxidation, how-
ever, the material was not filtered for 2 days after the 1-hour digestion. This may
414 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
account for the slightly higher results in this case. With the exception of the peroxide
method the checks in the other methods were very poor.
From the meagerness of this work and the poor checks obtained, it would be unwise
to draw any conclusions. However, of the methods tried, there is some indication
that the peroxide combustion, although quite lengthy, might prove more reliable for
the determination of total sulfur in soils.
V. H. Morris, Ohio Agricultural Experiment Station —Procedure I: (a) The extreme
heat called for in this procedure is hardly deemed necessary for the oxidation of the
sulfur. The term ‘‘extreme heat’’ was taken in this case to mean about 850°C. Such
an ignition leaves a residue very difficult to remove from the crucible. Iron was
eliminated in this procedure by precipitation as hydroxide in ammoniacal solution,
the silica being dehydrated and removed previously. (b) Difficulty was encountered
in this procedure in the enormous mass of silica which came out of solution on making
the filtrate acid. This was true especially with the sample of soil low in organic matter,
a charge of 50 grams being used. This method is not as effective as (a) in extracting
the sulfur.
Procedure Il: This method seems to be very effective particularly in removing the
sulfur added as magnesium sulfate. However, it does not extract all the sulfur originally
in the soil, this being shown in the soil sample high in organic matter.
Procedure III: Aqua regia does not appear effective. An attempt to remove the
iron as oxide failed, perhaps due to insufficient heating. It was then removed as
hydroxide, this method being used in all other cases where the elimination of iron was
necessary. It is possible that there was some loss of sulfur at this point by occlusion,
although two precipitations and washings of the hydroxide were made.
Procedure IV: Nitric acid appears to be much more effective with the soil sample
high in organic matter. This may be due to the smaller charge.
Procedure V: Difficulty was encountered in this procedure owing, presumably, to
the addition of ammonium oxalate. Upon concentrating the filtrate, heating with the
oxalate, filtering and washing, a considerable quantity of a crystalline precipitate
settled out. Qualitative tests proved this to be magnesium oxalate, although the
oxalate of magnesium is soluble and should be, particularly in such a large volume and
acid solution. An attempt was made to get the precipitate into solution; after decant-
ing the clear solution, it was immediately reprecipitated. It was then necessary to
remove the magnesium as magnesium ammonium phosphate. The solution required
15 cc. of hydrochloric acid to keep barium phosphate in solution when sulfates were
precipitated. It is possible that a small amount of barium phosphate was included
with the barium sulfate, since the results obtained in this procedure are slightly higher
than those from the sodium peroxide fusion.
DISCUSSION OF RESULTS.
Using the blank determination secured upon the native soil by the sodium peroxide
procedure, results submitted by the Oregon Experiment Station show a recovery of
but 89.7 per cent of the sulfur added to the soil by hydrochloric acid extraction of the
residue when iron was not removed, and 96.7 per cent by the same procedure when
iron was removed. The necessity for the removal of iron salts prior to the precipita-
tion of barium sulfate is emphasized by these results and by those of C. B. Williams in
1902. With the magnesium nitrate combustion the recovery of sulfate from the
untreated soil was greatest with the hydrochloric acid extraction, acetic acid and water
following in the order named. Applying the hydrochloric acid blank to the recovery
from the fortified soil the hydrochloric acid extraction without remoyal of iron gave a
98.7 per cent recovery from the addition of 0.1000 gram of calcium sulfate.
eet ee le ec ee ee el
hate
_
1922| MACINTIRE: REPORT ON SOILS 415
With the aqua regia digestion of two soils the checks were quite concordant, and when
applied to the respective total recoveries the amount of sulfate yielded was 99.8 and
99.7 per cent, respectively, for the technique involving the removal of ironand that per-
mnitting its retention in the solution from which the barium sulfate precipitation was
made. With the magnesium nitrate-calcium carbonate-ammonium chloride ignition
the water and hydrochloric acid extractions gave checks in the respective procedures;
but, when carried out with the fortified soil, the application of the blanks gave but
68.8 per cent of the added sulfate in the case of the water extraction as against 99.9
per cent for the hydrochloric acid extraction, the iron not having been removed from
the latter.
‘Lomanitz found wide variations between the several methods as tried upon each
native soil, the sodium peroxide fusion with water extraction and the magnesium
nitrate-calcium carbonate-ammonium chloride procedures giving the highest results
as compared with the calcium nitrate procedure in vogue at the Texas Experiment
Station. However, when the respective checks upon the native soils were applied to
the fortified soils, the highest average recovery was obtained by the nitric acid digest-
ion. The nearest approach to any single recovery of added calcium sulfate was also
obtained by the nitric acid digestion.
The results submitted by Prince showed a much higher determination by the sodium
peroxide procedure than by the nitric acid and the aqua regia digestions for the fortified
soil, when the iron was not removed by ammoniacal precipitation. This does not
mean necessarily that oxidation was less complete in the two wet digestions than in
the peroxide combustion method, but that the amount of sulfur leached from the soil
mass was less. However, from other work, it would seem probable that the lower
results were caused by the loss of sulfate during the reduction of the ferric salts to
insoluble oxides.
The data submitted by the Ohio Experiment Station may be used to stress some of
the findings of the referee as to the variations in the tendencies of the several procedures
when applied to different soils. In the case of the sodium peroxide fusion with Soil
No. 1, Table 4, a greater amount of barium sulfate precipitate was obtained by the
hydrochloric extraction of the fusion of the native soil than by the water extraction.
However, the reverse was true for this soil after it had been fortified with additions of
magnesium sulfate. The same experience was had by the referee in working with this
procedure.
With the magnesium nitrate procedure the greatest recovery was obtained from the
acetic acid extraction for both native and fortified soil low in organic matter. On the
other hand, in the case of the soil high in organic matter, the highest recovery from the
unfortified soil was obtained by the water extraction while the three extractions—
water, hydrochloric acid and acetic acid—gave practically equivalent results when this
soil was fortified by sulfate additions. The aqua regia digestion gave low results when
heating was resorted to in an effort to remove iron (followed ip this case by ammoniacal
precipitation). This result, also obtained by the referee, was shown to be due to the
dissociation of the sulfates, particularly magnesium sulfate, carried by the strong acid
filtrate. The nitric acid digestion gave interesting and promising results, especially in
the case of the soil high in organic matter, the recovery being greater than that secured
by the use of sodium peroxide and practically equivalent to that secured by following
the magnesium nitrate-calcium carbonate-ammonium chloride procedure. The mag-
nesium nitrate-calcium carbonate-ammonium chloride procedure gave results as a
rule higher than those secured by any of the other methods. The average of the four
determinations by this method was 0.0624 gram of barium sulfate as compared to
0.0575 gram of barium sulfate for a corresponding average by the nitric acid digestion
and 0.0553 gram of barium sulfate for the sodium peroxide ignition with hydrochloric
acid.
416 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Morris states that the results secured by the magnesium nitrate-calcium carbonate-
ammonium chloride procedure may be too high because, “it is possible that a small
amount of barium phosphate was included with barium sulfate”. As offsetting this
error, it should be noted that the strong solution of hydrochloric acid, from which the
barium sulfate was precipitated, would have had some appreciable solvent action upon
the barium sulfate.
Morris experienced trouble with a continued precipitation of magnesium oxalate.
W. M. Shaw of the referee’slaboratory encountered the same trouble. In the pre-
liminary work with this procedure, the referee used ammonium carbonate instead of
ammonium oxalate to effect removal of calcium and magnesium, and no trouble was
experienced in the use of the carbonate. It was thought best to substitute the oxalate
for the carbonate because the former could be more accurately added, since a consider-
able amount of the carbonate undergoes decomposition upon adding it to the warm
solution.
Since a number of analyses carried out in the preliminary studies by the referee had
demonstrated that the sodium peroxide procedure would not effect recovery of even an
approximation of added sodium sulfate and magnesium sulfate in the case of local
soils, Shaw did not carry out this procedure. His results indicate complete recovery
of added sulfates in the case of both the aqua regia and the nitric acid digestions.
Closely concordant, separate and average sulfate results were obtained by the aqua
regia and the nitric acid digestions where iron was removed by ammoniacal precipita-
tion, but it was apparent that the excessive heat required to convert the ferric salts to
iron oxides was responsible for either a volatilization or dissociation of the sulfate or
else a markedly decreased solubility of the sulfates in the acid solvents.
In the case of the fortified soil the results were low and non-concordant for both the
magnesium nitrate-calcium carbonate-ammonium chloride procedure and the aqua
regia digestion when iron was removed by heating; but both nitric acid and aqua regia
digestions gave theoretical recoveries when the iron was removed by ammoniacal
precipitations.
POSSIBLE LOSS OF SULFATES IN THE NITRIC ACID PROCEDURE, DUE
TO BARIUM NATIVE TO THE SOIL.
It is a well-known fact that some soils carry an appreciable amount of barium com-
pounds which might vitiate the sulfate result obtained by methods calling for acid
digestion. It was found that some of the soils studied at the Tennessee Experiment
Station contained this element. Since the nitric acid digestion procedure appears
well adapted because of its simplicity and rapidity, it seemed worth while to test the
possible influence of the occurrence of native barium upon the accuracy of the method.
The data secured demonstrate that all of the added sulfates can be recovered, when
applying the soil blank to the determination of the fortified soil, if iron is removed by
double ammoniacal precipitation; hence, the undetermined factors are the possible
interference of barium and the question of the completeness of the oxidation of all
forms of native organic sulfur within the period of boiling. It is planned to continue
the studies as to completeness of oxidation in the given time, using 1-hour, 2-hour
and 3-hour digestions.
In an effort to obtain light upon the tendency of the siliceous residues to occlude
sulfur, as barium sulfate, Shaw introduced freshly-precipitated barium sulfate into the
soil mass, prior to the 1-hour period of digestion with nitric acid, and compared the
sulfate recoveries with those from the unfortified soil. He also ran the barium sulfate
precipitate without soil as a further parallel. The steps of digestion, evaporation of
the nitric acid extract, the elimination of nitrates by repeated evaporations with hydro-
chloric acid, the precipitation of iron ammoniacally, the taking up with an amount of
1922] MACINTIRE: REPORT ON SOILS 417
hydrochloric acid necessary to bring all salts into solution and the neutralization of
this excess of hydrochloric acid prior to the addition of barium chloride, were all carried
out as in a normal procedure with an unknown. The results show an average carry-
through of 0.0142 gram of barium sulfate for the 0.1290 gram blank and an average of
0.0131 gram for the soil to which barium sulfate was added. Such a recovery would
indicate, rather strongly, that the method is not appreciably affected by amounts of
barium which are probably greater than those to be expected as native to the soil, the
amount of the barium sulfate impregnation in this case being equivalent to an occur-
rence of 0.03% barium, on the basis of a 25-gram charge. The peroxide ignition
method gave varying results with different soils and inconsistent recoveries with water
and the several acid extractions. The amounts of salts present at the time of the
precipitation of barium sulfate were excessive and dehydration of the siliceous mass
was required to obviate occlusion. Some of the data obtained also indicate the
probability of error as a result of uncontrolled temperature during the ignition.
In the case of the magnesium nitrate procedure it is apparent that variations in the
temperature of the electric furnace are reflected in the results. It is quite possible,
as indicated by numerous data obtained, that the magnesium sulfate may undergo
dissociation during the ignition process.
The magnesium nitrate-calcium carbonate-ammonium chloride procedure has given
satisfactory results in some instances, but it does not appear to be applicable to all
soils. It is doubtful if this or either of the other dry methods effects an absolute oxida-
tion of the soil sulfur, for each has in some instances yielded hydrogen sulfide when the
alkaline ignition residue was treated with hydrochloric acid.
The nitric acid digestion is preferable to the aqua regia digestion because of the
smaller amount of dissolved iron to be removed and the absence of the objectionable
fumes incident to the aqua regia procedure. It is evident that complete recovery may
be expected unless inhibitive amounts of barium should come into solution from the
soil during the digestion. It is furthermore established by many data that the iron
may not be eliminated through conversion of the iron salts into soluble oxides by
excessive heat, without bringing about a dissociation of the sulfates and loss of sulfur
trioxide, even when an abundance of the alkali or alkali-earth bases is added.
The intention was to secure a method of procedure which would accomplish two
things: (1) A complete conversion of all forms of sulfur to the sulfate radicle; (2) the
complete removal of all sulfates from the soil mass. It is essential, furthermore, to
have a procedure which is adapted to a larger bulk of the original soil because of the
low sulfur content in many soils. It is also desirable, if not in fact essential, that the
insoluble residue shall be in such condition as to facilitate filtration and washing, and
that the extract be not of excessive salt concentration. The wet method seems
decidedly preferable in caring for this essential factor.
RECOMMENDATION.
It is recommended that the following method be studied further:
Introduce 50 grams of soil low in organic matter, or 25 grams of soil high in organic
matter, into a 500 cc. Kjeldahl flask, heat slowly and boil for 1 hour. Insert a small
funnel in the neck of the flask. Follow the same procedure by boiling for a 2-hour
period and also for 3 hours. Cool, dilute to 400 cc. and pour off the clear liquid through
a Biichner funnel. Add 250-300 cc. of hot water, agitate, throw upon Biichner and
wash with hot water to a combined volume of 1 liter. Evaporate filtrate to dryness
at low temperature. Add 10 cc. of concentrated hydrochloric acid and again evaporate.
Repeat the addition of and evaporation with hydrochloric acid. Take up with a few
drops of hydrochloric acid; bring into solution and precipitate iron, by addition of 1to1
418 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
ammonium hydroxide, from a volume of 400 cc. Pour onto a Biichner and wash
twice. Transfer the filter to original beaker, dissolve, macerate the filter and again
precipitate from a volume of about 300 cc. and filter into original filtrate, washing to
a volume of 1 liter. Acidify filtrate with a slight excess of hydrochloric acid; concen-
trate to a volume of 400 cc.; add hot barium chloride (1 plus9) and agitate vigorously.
Permit barium sulfate to stand 18 hours and filter on an acid-washed asbestos Gooch
filter.
Norte.—In studying this method it would be well to add a small amount of freshly
precipitated barium sulfate to the soil prior to the digestion and determine the point
at which it may be lost to the procedure, in order to ascertain what may be expected
from any barium sulfate formed during the digestion because of the occurrence of
barium compounds native to the soil. The method should also be tested by the addition
of known amounts of sodium, potassium, calcium and magnesium sulfates.
REPORT ON SULFUR.
By W. H. MacIntie (Agricultural Experiment Station, Knoxville,
Tenn.), Associate Referee.
The referee was instructed to study sulfur as it relates to soil problems.
The writer and W. M. Shaw of the same laboratory directed their work
toward the thesis of the chemically induced formation of sulfates from
flowers of sulfur as compared to that induced by biological agencies.
This laboratory work was done with quartz media and it was runin
parallel with lysimeter studies. Preliminary papers have been pub-
lished'. A more extensive report will be offered in the near future.
REPORT ON FOODS AND FEEDING STUFFS.
By J. B. Reep (Bureau of Chemistry, Washington, D. C.), Referee.
The referee considered the different methods of determining the
presence of sulfur dioxide in bleached grains and found that the one
generally used is that by W. P. Carroll*. As this method has not been
found entirely satisfactory, D. A. Coleman and his associates of the
Bureau of Markets, Department of Agriculture, have studied various
other methods. It is their opinion that the method of treating the
sample with a non-volatile acid, such as phosphoric or tartaric, dis-
tilling and collecting the distillate in an acidified solution of potassium
iodate to which starch has been added, is much better than the Carroll
method. However, it has not been tried out by a sufficient number of
chemists to warrant its recommendation for adoption as an official
method.
1 Soil Science, 1917, 4: 231; 1921, 11: 249; J. Ind. Eng. Chem., 1921, 13: 310.
* U.S. Bur. Plant Ind. Circ. 40: 1909.
A
‘
4
1922] REED: REPORT ON FOODS AND FEEDINGS STUFFS 419
Methods for the determination of acidity in corn have been con-
sidered, and a comparative study of the Black and Alsberg! and the
electrolytic hydrogen ion concentration methods has been made by
C. D. Garby?. The work of L. H. Bailey and C. Thom* and others
indicates that the method of Black and Alsberg is satisfactory for all
practical purposes for determining acidity in grains, and it requires less
complicated apparatus and less skill in manipulation than the electro-
lytic hydrogen ion concentration method. However, as little is known
of the nature of the changes which take place in corn and other grains
as the acidity increases and owing to the fact that it has been found by
Bailey and others that the acidity is not as definitely indicative as has
been thought, it does not seem desirable to recommend any method as
official until the changes which take place are better understood, and
the degree of acidity has greater significance.
The existing official method for determining water in foods and feed-
_ ing stuffs has been considered, and the conclusion is that several official
5
methods should be adopted, the method to be used depending upon the
nature of the product under examination. In each case the simplest
and most rapid accurate method for any given product should be used.
In the opinion of the referee the method of drying a weighed sample to
constant weight in a suitable dish on the water bath should be used
wherever possible on account of its simplicity. Next in simplicity is the
method of drying in a vacuum at the boiling point of water. It should
be used with products the moisture of which can not be determined
satisfactorily by the first method.
The moisture in some products can not be determined at the boiling
point of water on account of certain changes which take place at that
temperature which affect the results. With products of this kind the
determination should be made by heating in vacuum at from 65 to
70C°. It has not been decided just what temperature will give the
most satisfactory results. Some products, however, can not be heated
to 65° in vacuum without vitiating the results of the moisture deter-
mination. The moisture of products of this kind should be determined
by drying in a desiccator in vacuum over sulfuric acid.
The problem which presents itself is to decide what method for the
determination of moisture shall be used on the various foods and feed-
ing stuffs, that is, to classify the products as to the method which should
be used in the determination of moisture in them. It will be necessary
to get the opinion of many food analysts. Though this whole problem
may be difficult, it seems possible that a fairly satisfactory classification
may be worked out in time.
s oe s. Bur. Plant Ind. Bull. 199: (1910), 10.
Thesis, ‘“Electrometric laa and its application to Corn Meal”, 1921. May be consulted at George
Washington University Lib:
* The Operative Miller, 1920, ‘25: 368.
420 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
The methods for the detection of reground bran and shorts presented
in 1920 by J. B. Reed! and D. B. Bisbee* have been studied further and
although they may be valuable as methods for detecting ground bran
in shorts, it is believed that neither one of them taken alone is sufficiently
reliable in the hands of those who have not had considerable experience
with it so that the referee can recommend its adoption as official.
The motion made by G. 8S. Fraps that the words “‘or asbestos” be
inserted after the word “linen” in the official crude fiber method has
been considered, and it is believed that this point should be disposed of —
in connection with the report on crude fiber.
The motion by G.S. Fraps that the first and second sentences in the
official method for the determination of ether extract*® be deleted has
been considered by the referee. In view of the facts that it was necessary
to adopt the Roese-Gottlieb‘ method for the determination of ether
extract in dairy products and that a modification of that method is
being used in the Bureau of Chemistry on noodles, macaroni and like
products, it is possible that the present official method for the deter-
mination of ether extract may not be entirely satisfactory for all the foods
and feeding stuffs on which it is being used. Therefore it would seem
desirable to make a more extended study of the subject to determine
whether it will be necessary to make fundamental changes in the method.
If that is found necessary, it will be easier to make all of the changes at
one time.
RECOMMENDATIONS.
It is recommended—
(1) That the method of treating the samples with a non-volatile acid,
such as phosphoric or tartaric, distilling and collecting the distillate in
an acidified solution of potassium iodate, to which starch has been
added, be studied further in comparison with the Carroll and other
methods.
(2) That no method for determining the acidity in corn and other
cereals be adopted at present.
(3) That the referee attempt to classify products according to the
method which should be used in determining moisture in them; that the
various methods be studied and simplified by rewording; and that the
conditions of temperature, pressure and other factors be fixed more
definitely.
(4) That the referee study methods of determining ether extract in
various foods and feeding stuffs the coming year, with a view to ascer- —
taining whether or not the official method is applicable to all of the
products for which it is now being used.
WJ. ees Official Agr. Chemists, 1921, 5: 70.
2 [bid., 74
3 Assoc. Official Agr. ee sakes, 1920, 227.
* Z. Nahr-Genussm., 1905, 9
/
1922| BIDWELL: REPORT ON CRUDE FIBER 421
REPORT ON CRUDE FIBER.
By G. L. Bipwett (Bureau of Chemistry, Washington, D. C.), Referee.
At the meeting of this association in 1920 a paper, entitled “A Study
of the Details of the Crude Fiber Method’’, was presented by G. L.
Bidwell and L. E. Bopst. This paper contained a proposed method for
crude fiber which gives concordant results if followed exactly. During
1921 additional study of this method was made. A copy was sent to
practically all of the collaborators for criticism and reports. As a
result of careful examination some valuable suggestions were offered.
Many of these suggestions were incorporated in a rewritten method
which, it is hoped, will meet with the approval of the association. The
method follows:
REAGENTS.
(a) 1.25% sulfuric acid solution.—Contains 1.25 grams of sulfuric acid per 100 ce.
(b) 1.25% sodium hydroxide solution—Contains 1.25 grams of sodium hydroxide per
100 cc., free, or nearly so, from sodium carbonate.
The strength of these solutions must be accurately checked by titration.
Asbestos.—First digest on steam bath over night with 5% to 10% sodium hydroxide
and thoroughly wash with hot water; then digest over night with 5% to 10% hydro-
chloric acid and again wash thoroughly with hot water; next ignite completely at bright
red heat.
APPARATUS.
Water-jackeled condenser (about 15 inch).
Assay flask.—Capacity about 700 cc., diameter of base 314 inches, 714 inches tall,
and tapering to fit a No. 10 rubber stopper. In case the assay flask is not available a
500-750 cc. Erlenmeyer flask may be used.
Linen.—Linen should be of such character that while filtration is rapid no solid matter
passes through. The linen which has proved most satisfactory has 46x50 threads per
inch. The threads are of large size as compared to the number of threads per inch and
are loosely twisted. Any linen approximating these specifications will prove satis-
factory.
DETERMINATION.
Extract 2 grams of the dry material with ordinary ether, or use the residue from the
ether extract determination and transfer the residue, together with 14 to 1 gram of
asbestos, to the assay or Erlenmeyer flask. (Where the residue from the ether extract
is used and the proper amount of asbestos has already been added, further addition is
unnecessary.) Using a calibrated beaker, add 200 cc. of boiling sulfuric acid (A) to
the contents of the flask, place immediately on the heating battery and connect with
the water-cooled condenser. It is essential that the contents of the flask come to
boiling within 1 minute after being placed upon the battery and that the boiling con-
tinue briskly for 30 minutes. It was found best to rotate the flask with the hand about
every 5 minutes in order thoroughly to mix the charge. Care should be taken to keep
the sides of the flask above the solution free from the sample. A blast of air conducted
into the flask will serve to reduce the frothing of the liquid. Remove flask at the
expiration of the 30 minutes and immediately filter through linen in a fluted funnel and
wash with boiling water until the washings are no longer acid.
422 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
Next wash the charge and adhering asbestos back into the flask with 200 cc. of boil-
ing sodium hydroxide solution (b) using a 200 cc. wash bottle. (The transfer of the
sample to the original container is very easily accomplished by this means.) Bring
the sodium hydroxide to boiling and keep at this temperature under a reflux condenser
while in use. (The sodium hydroxide is best transferred to a 200 cc. wash bottle by
means of a bent tube through which the liquid is forced by blowing into a tube connected
with the top of the condenser.) Then place the flask in the heating battery, connect
with the reflux condenser and boil for exactly 30 minutes. The boiling with the alkali
should be so timed that the contents of the different flasks will reach the boiling point
approximately 3 minutes apart. This provides sufficient time for filtration. The last
filtration takes place directly into a Gooch crucible, which has been prepared previously
with a thin but close layer of ignited asbestos. Employ suction and wash the contents
thoroughly with hot water and then with about 15 cc. of 95% alcohol.
Dry the crucibles with their contents to constant weight at 110°C. in an electric
oven, usually overnight. After weighing, incinerate the contents of the crucibles in
an electric muffle or on a Meker burner at a dull red heat until the carbonaceous matter
has been removed—20 minutes is usually sufficient. Cool in a small, tight, efficient
desiccator and weigh. The loss in weight is taken as crude fiber.
It is recommended that this method be adopted by the association.
A lengthy discussion followed this report in view of the change sug-
gested in the official method. The referee reported that the addition
of asbestos was practically the only difference and emphasized the point
that the variation in results was not due so much to the method itself
as to the details followed by the collaborators in running the method.
ASTUDY OF THE GEPHART METHOD FOR THE DETERMI-
NATION OF CRUDE FIBER.
By Leste E. Borst and Grorce L. Brwewu (Bureau of Chemistry,
Washington, D. C.).
A method for the determination of crude fiber, primarily intended for
that determination in cocoa, was developed by F. C. Gephart, a
consulting chemist of New York. This method was studied with the
cooperation of Gephart to see if it had any possibilities as a general
crude fiber method. The characteristics which made it attractive were
that it needed no condenser, did not foam and required no filtering.
The method is as follows:
Weigh out directly into the special silica tube from 14 to 1.0 gram of the material.
Add 40 cc. of ether, stir thoroughly and centrifuge for 5 minutes at a speed of 3000
revolutions per minute. Carefully pour off the supernatant ether and repeat the opera-
tion with a second portion of 40 cc. of ether. Dry the tube and contents, add 40 cc.
of boiling 1.25% sulfuric acid and digest in a boiling water bath for 30 minutes, stirring
the contents of the tube frequently with a glass rod provided with a hooked end. Centri-
fuge for 10 minutes at the same speed, pour off supernatant liquid, add 40 ce. of boiling
water, stir and centrifuge for 10 minutes, repeating the washing operation with a second
portion of hot water. Add 40 cc. of boiling 1.25% sodium hydroxide and digest in
1922] BOPST—BIDWELL: DETERMINATION OF CRUDE FIBER 423
boiling water for 30 minutes. Centrifuge as before, wash with 2 portions of boiling
water, and finally with 40 cc. of a 50-50 mixture of alcohol and ether. Dry at 105°C.
to constant weight, ignite and weigh. The difference in weight is taken as crude fiber.
As this method was first used in cocoa and chocolate work by
Gephart, it was thought advisable to try it upon the same type of samples.
Fiber was determined upon cocoas of different standards of purity
by the Gephart method and by the proposed method with the follow-
ing results:
: TABLE 1.
Determinations of crude fiber in cocoa.
QUALITY OF PROPOSED GEPHARTS
COCOA METHOD METHOD
per cent per cent
Standard aasyserir oi 5.83 5.51
High grade.......... 4.85 4.97
Standard: 2.555. 5.35 5.91
The figures in Table 1 show that the Gephart method gives
slightly higher results (with one exception) than the proposed method.
This is probably due to the fact that filtration after acid digestion
removes some of the material which can not be eliminated by Gep-
hart’s method.
These methods were also tried upon samples of widely varying fiber
content with the following results:
TABLE 2.
Determinations of crude fiber in various feeding miztures.
PROPOSED | GEPHART'S
rae METHOD fe METHOD
per cent per cent
Alfalfa, corn meal and cottonseed meal. . 13.90 14.58
Alfalfa=corn meal 508 3258 fo Se hice 8.62 8.87
Grain dust (low fiber content)......... 9.03 9.66
Grain dust (high fiber content)........ 23.20 25.55
Corn cob cellulose... .-........60e20+0s 61.45 66.68
Wiens ee 023 = sé 0.40
Gobtouseedimeal*s: 4. sbaStaatece 8.25 10.95
It is apparent from these results that the greater the amount of fiber
in a sample the greater the range of difference between the two methods.
Samples of low-fiber content with the exception of flour check fairly
well, but the variance between the results increases as the fiber content
increases.
424 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTs [Vol. V, No. 3
It is thought that this method will be of value in the case of samples
having the texture of cocoa and spices which are very difficult to filter
when no asbestos is used. However, if the proposed method for the
determination of crude fiber be adopted, very little difficulty will be
experienced in filtering any material.
REPORT ON STOCK FEED ADULTERATION.
By H. E. Genser (Bureau of Chemistry, Department of Agriculture,
Harrisburg, Pa.), Associate Referee.
As associate referee on stock feed adulteration, the writer has developed
a method for the quantitative determination of grit and bone in poultry
feeds and animal by-products.
The method follows:
Estimation of grit in poultry feeds and other similar feeds.
After thoroughly mixing, place 2 grams of the ground sample prepared for the
determination of protein, fat and fiber, or 2 grams of a representative portion of the
original sample, ground to pass through a mm.- or a 20-mesh sieve, in an evap-
orating dish of about 30 cc. capacity.
Add about 5 cc. of chloroform and mix gently with a glass rod so that the liquid
comes in contact with all of the sample. Brush the particles adhering to the rod into
the dish and, after pushing all particles into the chloroform with a 25-mm. circular or
square cover-glass, use the latter to skim off and pull the floating portion of the material
over the top of the dish, taking care not to submerge the cover-glass enough to disturb
the grit settled in the bottom of the dish. After skimming until the surface of the
chloroform is rather clear, slowly pour the supernatant liquid into a second evaporating
dish, stopping the pouring as soon as any grit threatens to pass out.
Now wash the sides of the dish with a few cc. more of chloroform and repeat the
above operation until no floating particles remain, using the cover-glass as before and
pouring off the supernatant liquid. This will require from 10-15 cc. of chloroform.
When grit only remains, drain out chloroform and allow to dry. Weigh to constant
weight.
WEIGHT OF GRIT X50 = PER CENT OF GRIT.
Notre.—The chloroform washings collected in the second dish should be poured out
in order to observe whether any grit has been poured into it during the process. If
any number of tests are to be made, the chloroform washings may be saved and
recovered by distillation and subsequent drying over calcium chloride.
Estimation of bone in meat scrap.
The method for the estimation of grit in poultry feeds is employed, except that in
some samples it may be found necessary to rub the residue of bone, remaining after
washing with chloroform, with a glass rod or small pestle to assist in bringing some of
the particles to the surface of the chloroform.
WEIGHT OF BONE xX 50 = PER CENT OF BONE.
Hight samples were prepared to be sent to the collaborators, four of
which were mixtures of unknown ingredients, submitted for the purpose
1922] GENSLER: REPORT ON STOCK FEED ADULTERATION 425
of qualitative identification of these ingredients as well as the deter-
mination of grit in the same by means of the suggested method.
The remaining four were samples of animal by-products, containing
various proportions of bone, submitted for the purpose of applying the
proposed method in estimating the percentage of bone present.
The poultry feeds, in the case of Samples 1, 2, 3 and 4, were com-
pounded from a mixture of corn, oats, wheat, barley, buckwheat, kafir
and sunflower seed, containing also a trace of rye and flaxseed, the
mixture being ground to pass a 20-mesh sieve. In addition to the
ground grains, the 4 samples also contained ground grit and locust bean
meal, as follows:
(1) 1% of grit and 10% of locust bean meal (latter declared).
(2) 3.5% of grit and 0.5% of locust bean meal.
(3) 5% of grit and 5% of locust bean meal.
(4) 8.2% of grit and no locust bean meal.
The locust bean meal was used to give practice in the utilization of
a standard in microscopic examinations, as well as to show ability to
detect small amounts of ingredients.
Samples 5, 6, 7 and 8 were meat and bone meal products ground to
pass a 20-mesh sieve. Sample 5 was a factory product, containing 15.7
per cent of bone, and was used as a base in preparing Sample 6, which
contained 35.8 per cent of bone. Samples 7 and 8 were prepared from a
commercial meat product containing, originally, no bone, but later
diluted so as to contain 8.4 per cent and 21.0 per cent of bone, re-
spectively. As indicated, bone was added to these samples in varying
amounts and in presenting the figures due consideration was given to
the fact that the bone included 4.35 per cent of moisture, 2.68 per
cent of residue and non-extractive matter, and 8.90 per cent of ether
extract. Therefore, the results obtained, as well as those reported by
the collaborators, were considered to represent pure bone.
These 8 samples, together with a copy of the proposed method and
instructions for examination, were sent to 21 collaborators who had
signified their desire to cooperate in the work. Results were received
from 12 collaborators and tabulated.
The results reported by the collaborators in the determination of grit
in ground feeds were remarkably close to the theoretical amounts in
each of the samples. The widest variation, as will be noted, amounted
to only 1.0 per cent in one case—Sample 4. The average results were
also very close to the theoretical amounts in the mixture. O. B. Winter,
of Michigan, reported the following as having been obtained by the use
of carbon tetrachloride: Sample 1, 1.1 per cent; Sample 2, 3.1 per cent;
Sample 3, 5.5 per cent; Sample 4, 8.4 per cent; Sample 7, 8.8 per cent
and Sample 8, 21.8 per cent, in addition to the results obtained by the
use of chloroform.
426 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
TABLE 1.
Determination of grit in ground feeds.
ANALYST'S SAMPLE 1, SAMPLE 2, SAMPLE 3, SAMPLE 4,
No. 1.0 %* 3.5 %* 5.0%? 8.2%*
per cent per cent per cent per cent
2 1.4 3.9 5.1 8.3
3 1.1 3.7 5.0 8.0
6 ies 3.5 4.8 8.3
7 1.6 3.7 5.4 8.0
8 1.4 3.9 5.7 8.5
10 1.1 3.5 4.9 Teh
12 0.9 3.4 4.5 7.4
14 foe ane a0 a AL
16 1.0 3.3 4.4 7.2
17 1.1 3.8 4.6 8.6
19 1.0 3.4 4.5 7.9
21 1.1 3.3 4.7 7.6
Average......... 1.6 3.6 4.9 8.0
*Actual percentage of grit present.
TABLE 2.
Determination of bone in meat products.
ANALYST’S SAMPLE 5, SAMPLE 6, SAMPLE 7, SAMPLE 8,
No. 15.7 %* 33.8 Go 8.4%" 21.0 %*
per cent per cent per cent per cent
3 14.8 35.5 8.3 20.3
6 14.2 33.3 7.9 19.4
7 14.0 33.7 8.2 20.5
8 16.2 35.7 8.6 21.6
10 16.1 37.1 8.6 22.0
12 13.7 32.9 8.3 20.7
14 14.8 35.7 8.8 22.0
16 15.1 34.2 8.2 19.4
ily/ 14.9 36.3 8.8 19.9
19 15.6 36.1 8.6 21.5
21 15.1 36.5 8.8 20.8
Average......... 14.9 35.2 8.5 20.8
*Actual percentage of bone present.
In the determination of bone in meat products, the results obtained
were also in very close agreement with the theoretical amounts. The
widest variations reported were 2.0 per cent in Sample 5; 2.9 per cent in
Sample 6; 0.5 per cent in Sample 7 and 1.6 per cent in Sample 8. The
latter figures, as previously explained, were obtained by the use of the
factor which took into account constitutents other than actual bone,
applied to the percentage of bone employed in making the mixtures.
—
1922| GENSLER: REPORT ON STOCK FEED ADULTERATION 427
These results would indicate the practicability of using such a method
in estimating the amounts of grit or bone in certain feeds.
The results reported covering the identification of ingredients in the
4 samples of mixed feed were very good, indicating that one trained in
TABLE 3.
Identification and relative amount of ingredients compared to standard*.
LOCUST BEAN, 10%
: FLAX-
ANALYSTS RYE | BUCK- | MILO OR (Standard for Sample
conN | OATS | WHEAT | BARLEY SEED a
No. (Trace) | WHEAT | KAFIR 2, 0.5%; Sample 3,
5 %; Sample 4, None)
a ee
Sample 1
2 SP DES PS bese SL i Sen Found present.
3 ST Ae 4h ST Found present.
8 Seg oebe es msec eS | Sun Found present.
12 Sur 8 TEU AS) SS eee | lets Found present.
17 7 efit er Ee Ab nee Found present.
19 Sib] PASS |) AS hel pA |e eee fate 10%.
Sample 2
2 Sete Sm tas wba ime: Sits Less than Sample
3. (Estimated
1%).
3 Scr iu Ah Sic ay T Less than
Sample 1
8 Sie Sie See See Sot iLSit 0.5%.
12 ST 8 Sik |S) ST Small amount—
less than 5%.
17 oe T . | About 1%.
19 Sita S Poe Ske (asia: Sit Less than 10%.
Sample 3
2 Se Lt Seales: MO adres. Se E Less than
Sample 1.
(Estimated 5%).
3 Sra |) od 7: ST At: More than
Sample 1.
8 SSSR aS se Y t ST lo
12 ST s SSE || Sak ST About same as
Sample 1.
17 not cheat dase 1 Osean Eeeee T About 5%.
19 Si See tes oS) close. | seks More than
Sample 1.
Sample 4
2 Ser | Ser Sia ome sme: Less than
Sample 2.
‘Estimated0.25%).
3 ST T Ab ye! L Ss Less than
Sample 1.
8 Sew Saks abe eS wo S ST Bare trace.
12 ST s Sek Sa Shit None.
17 we ih PANE oc te None.
19 SLES ESP ES ted PSI te S$ T None.
S—Starch detected. T—Tissue detected.
s—Trace of starch detected. t—Trace of tissue detected.
*Analyst 19 also found a trace of sunflower seed in Sample 4.
428 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
this line of work can easily identify the ingredients of a feed. Prac-
tically every ingredient was identified by the collaborators.
The reports on the detection and estimation of locust bean meal are
especially interesting. One analyst reported the exact amounts in
Samples 2 and 3, while another made an estimate close to the figures
for the same samples. Other analysts made comparisons, which indi-
cate that while it is difficult to determine the exact amount of one
ingredient, such as locust bean meal, it is often possible to form an opinion
as to the approximate amount of an ingredient. When it is remembered
that Sample 2 contained locust bean meal in such small quantity that
it would amount to only ten pounds per ton, the ability of the col-
laborators to detect it indicates that small amounts of ingredients can
usually be identified. However, it is considered by analysts as well as
control officials that when an ingredient is claimed it should be present
in amounts readily identifiable.
It would appear desirable at this time to recommend that some method,
such as above presented, be studied further with the object of deciding
its worthiness for official adoption. The close results obtained by
Winter with the use of carbon tetrachloride suggests the advisa-
bility of further study with liquids having a specific gravity similar to
the one employed by your referee this year.
While it may not be practicable to attempt to develop the work to
such an extent that analysts can give final statements in the deter-
mination of amounts of ingredients in feed mixtures, the work of this, as
well as of previous years, points to the belief that approximations can
be made. It would be considered advisable to encourage the collabora-
tors of the several States to take part in the work so that the reports on
identifications, as well as on quantitive determinations of ingredients in
feeding stuffs, may be made more uniform.
It is recommended—
That further study be made of the methods described in the associate
referee’s report for the estimation of grit in poultry feeds and other
similar feeds and for the estimation of bone in meat scrap.
The appointment of the following committees was announced by the
president:
Committee on nominations: R. W. Balcom of Washington, D. C.,
R. N. Brackett of South Carolina and H. C. Lythgoe of Massachusetts.
Committee on resolutions: Wm. Frear of Pennsylvania, Julius Hortvet
of Minnesota and Miss B. H. Silberberg of Washington, D. C.
Committee on auditing: J. W. Kellogg of Pennsylvania and J. J. T.
Graham of Washington, D. C.
Commitlee lo wait upon Secretary of Agriculture: R. E. Doolittle of
Illinois, B. B. Ross of Alabama and E. M. Bailey of Connecticut.
Committee to wait upon the Honorary President: B. B. Ross of Alabama,
F. P. Veitch of Washington, D. C., and H. D. Haskins of Massachusetts.
FIRST DAY.
MONDAY—AFTERNOON SESSION.
REPORT ON SACCHARINE PRODUCTS!
By H. S. Patne (Bureau of Chemistry, Washington, D. C.), Referee.
Reports have been received from all the associate referees. J. F.
Brewster was appointed to succeed F. W. Zerban, who was unable to
continue as Associate Referee on Sugar House Products. C. H. Jones
was appointed Associate Referee on Maple Products. S. F. Sherwood
and O. S. Keener have continued their work on honey and maltose
products, respectively.
It is gratifying to note from this year’s reports that considerable
progress has been made. In most cases, however, the collaborative
work has not been carried far enough to warrant recommending that
definite action on the methods be taken at this time. Accordingly, it
is hoped that the investigations of saccharine products, now well under
way, may be actively continued.
DETECTION OF ARTIFICIAL INVERT SUGAR IN HONEY}.
By Sipney F. SHERwoop (Bureau of Plant Industry, Washington, D. C.),
Associate Referee.
The resorcin and the aniline chloride tests for the detection of com-
mercial invert sugar sirup in honey were adopted as tentative methods?
on the recommendation of F. L. Shannon? who, as Associate Referee on
Honey, had investigated numerous tests. His investigations did not
extend to honeys that had been heated to comparatively high tempera-
tures and, as question has been raised regarding the value of the tests
in the case of heated honeys, it was considered advisable to extend the
investigation to include honeys which had been so treated.
In the processes ordinarily used for the manufacture of commercial
invert sugar, inversion is accomplished by heating sucrose solutions to
which a very small percentage of acid has been added. If solutions of
d-fructose are heated to a high temperature, especially in the presence of
1 Presented by C. F. Walton, Jr.
2 Assoc. Official Ss af Chemists, Methods, 1920, 112.
8 J. Assoc. Official Agr. Chemists, 1916, 2: 169.
429
430 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
acid, the sugar is decomposed with the formation of more or less oxy-
methyl-furfural. Therefore commercial invert sugar sirup which has
been manufactured by processes requiring heating ordinarily affords a
positive reaction with these tests. The amount of furfural present may
be large or small, depending upon conditions of manufacture, and no
conclusions can be drawn from the tests as to the amount of the adul-
terant present.
C. A. Browne! states: ‘With natural honeys which have been
boiled or heated to a high temperature for any great length of time,
traces of furfural are formed just as in the invert sugar sirups, and these
honeys will then react with the aniline reagent. The boiling of honeys,
however, is a most questionable operation at best, the flavor of the honey
being completely destroyed by this process of cooking. Careful pro-
ducers and bottlers of honey take extreme pains in putting up their
products not to expose the extracted honey to a temperature exceeding
80°C. (176°F.). A positive reaction of a honey with aniline acetate may,
therefore, be regarded as an almost certain indication of adulteration
with invert sugar’. E. F. Phillips? states that honey should never be
liquefied by direct application of heat, and that it should never be
heated to a temperature greater than 160°F. (71.1°C.), as honey that is
heated to 180°F. (82.2°C.) loses flavor and becomes darker in color.
The value of the resorcin, aniline chloride and other tests has been
widely investigated, especially in Germany, and the following comments,
with regard to the resorcin test, are typical of the conclusions. H.
Kretzschmar? examined a large number of commercial honeys and
indicates the reliability of the test. M. H. Quantin* concludes that in
honey expressed or handled in ordinary manner at ordinary tempera-
tures the presence of furfural indicates the presence of a foreign material,
and that the presence of furfural in honey prepared by heating is not
sufficient proof of the presence of commercial invert sugar. O. Liining®
concludes that the value of the resorcin test is much lessened in the case
of heated honeys. In the case of two samples, heated for two hours at
80-85°C., he obtained a slight, quickly disappearing, red color. Heat-
ing the two samples to 80-85°C. for two hours and then keeping them at
60-50°C. for eighteen hours, he obtained in one case a strong red color
and in the other a weak one. He refers to the investigations of Fiehe
and Stegmiiller® who heated honeys for four hours at 70°, 80°, 85°, and
90°C. and obtained only a faint, quickly disappearing, red color. (A
positive test is indicated by an immediate orange-red color changing at
once to a cherry or dark red. ‘This color persists for hours.)
1U.S. Bur. Chem. Bull. 110: (1908), 68.
2U.S. Bur. Entom. Bull. 75: 1907, Part I.
3 Z. Nahr. Genussm., 1914, 28: 84.
4 Ann. Chim, anal., 1910, 15: 299.
5 Z. Nahr. Genussm., 1915, 29: 117.
6 Arb. Kais. Gesundh, 1912, 40: 336.
e
1922] SHERWOOD: DETECTION OF ARTIFICIAL INVERT SUGAR IN HONEY 431
Thesamples of honey used in the present investigation were as follows:
SAMPLE NO. NAME ACIDITY
per cent
1 Tupelo 0.12
2 Clover 0.19
3 Clover* 0.41
4 Honeydew 0.20
(Hawaiian)
i
*Contained added tartaric acid: 2 grams to 500 grams of honey.
The acidity was determined by titration with 0.1N sodium hydroxide’,
and is expressed as “per cent free acid as formic”. The acidity, on this
basis, of 100 samples of American and Hawaiian honeys (including
honeydew honey) is, maximum 0.25, minimum 0.04'; that of 72 samples
of honey from Cuba, Mexico, and Haiti is, maximum 0.43, minimum 0?.
Series A.—Heated for 1 hour at 160°F. (71.7°C.).
Series B.—Heated for 4 hour at 180°F. (82.2°C.).
Series C.—Heated for 20 minutes at 208-209°F. (97.8 to 98.3°C.).
Series X.—Original Tupelo honey plus 20% of commercial invert sugar sirup pre-
pared according to the method of Herzfeld’.
The directions followed in making the tests were identical with those
given in Methods of Analysis‘. A positive reaction in the case of the
resorcin test is an orange-red color appearing immediately and quickly
turning to cherry or dark red. In the case of the aniline chloride test
it is a bright red color appearing at once.
The collaborators were J. M. Webre, Temtor Corn and Fruit Products
Co., St. Louis, Mo.; C. G. Church, Fruit and Vegetable Chemistry
Laboratory, Bureau of Chemistry, Los Angeles, Calif.; C. P. Wilson,
Citrus Exchange By-Products Laboratory, Corona, Calif.; and A. V.
Fuller, Service Division, American Sugar Refining, Co., 117 Wall St.,
New York City.
The reports of the collaborators are as follows:
1U. 8S. Bur. Chem. eat 110: (1908), 49.
j Ibid., 154: (1912),
?U.S. Bur. Chem. "Bail. 110: (1908), 64.
4 Assoc. Official Agr. Chemists, Methods, 1920, 112.
432 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
TABLE 1.
Resorcin Test.
(Bryan's modification of Fiehe’s test.)
SERIES A.
(Heated for 1 hour at 160°F.—71.7°C.)
Sample SHER-
No. Time WEBRE CHURCH WILSON FULLER WwooD
1 Immediate Slight trace Negative Negative Negative Negative
1 minute Strong trace Negative Negative Negative Negative
5 minutes Strong trace Negative Negative Negative Negative
Immediate Doubtful Negative Negative Negative Negative
2 1minute Doubtful Negative Negative Negative Negative
5 minutes Doubtful Negative Negative Negative Negative
Immediate Doubtful Negative Negative Negative Negative
3 1 minute Slight trace Negative Negative Negative Negative
5 minutes Pink Negative Negative Faint pink Negative
Immediate Doubtful Negative Negative Negative Negative
4 1 minute Doubtful Negative Negative Faint yellow Negative
5 minutes Doubtful Negative Negative Faint yellow Negative
SERIES B.
(Heated for 1% hour at 180°F.—82.2°C.)
Immediate Negative Negative Negative Negative Negative
1 1 minute Slight trace Negative Negative Negative Negative
5 minutes Positive Negative Negative Faint yellow Negative
Immediate Negative Negative Negative Negative Negative
2 1 minute Negative Negative Negative Pink — Negative
5 minutes Doubtful Negative Negative Faint pink Negative
Immediate Slight trace Negative Negative Negative Negative
3 1 minute Trace Negative Negative Pink Negative
5 minutes Strong trace Negative Negative Pink Negative
Immediate Doubtful Negative Negative Negative Negative
4 1 minute Slight trace Negative Negative Negative Negative
5 minutes Pink-positive Negative Negative Very faint Negative
pink,
1922] SHERWOOD: DETECTION OF ARTIFICIAL INVERT SUGAR IN HONEY 433
SERIES C.
(Heated for 20 minutes at 208 to 209°F.—97.8 to 98.3°C.)
Immediate Negative Negative Negative Negative Negative
1 1 minute Trace Negative Negative Negative Negative
5 minutes Positive Negative Negative Very faint Negative
pink.
Immediate Negative Negative Negative Negative Negative
2 1 minute Trace Negative Negative Pink Negative
_5 minutes Positive Negative Negative Pink Negative
Immediate Slighttrace- Negative Negative Negative Negative
3 1 minute Trace Negative Negative Decided pink Negative
5 minutes Positive Negative Negative Decided pink Negative
Immediate Slight trace Negative Negative Negative Negative
4 1 minute Trace Negative Negative Negative Negative
5 minutes Positive Negative Negative Decided Negative
yellow
SERIES X.
(Original Tupelo honey plus 20% of commercial invert sugar sirup prepared according
to method of Herzfeld*.)
Immediate Orange red Negative Negative Negative Cherry red
X 1 minute Cherry red Pink Negative Negative Cherry red
5 minutes Dark red Pink Negative Negative Dark red
*U. S. Bur. Chem. Bull. 110: (1908), 64.
TABLE 2.
Aniline chloride test.
(Feder’s)
SERIES A.
(Heated for 1 hour at 160°F.—71.7°C.) z
Sample SHER-
No. Trme WEBRE CHuRCH WILson FULLER wooD
Immediate Negative Negative Negative Darkening Negative
1 1 minute Negative Negative Negative Darkening Negative
5 minutes Trace Negative Negative Darkening Negative
Immediate Negative Negative Negative Pinkish Negative
2 1 minute Negative Negative Negative Brownish Negative
5 minutes Negative Negative Negative Brownish Negative
Immediate Slight trace Negative Negative Pinkish Negative
3 1 minute Slight trace Negative Negative Pinkish Negative
5 minutes Slight trace Negative Negative Reddish Negative
brown
Immediate _ Positive Negative Negative Pinkish Negative
4 1 minute Positive Negative Negative Pinkish Negative
5 minutes Positive Negative Negative Brown Negative
434 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
SERIES B.
(Heated for % hour at 180°F.—82.2°C.)
Immediate Slight trace Negative Negative Slight pinkish Negative
1 1 minute Slight trace Negative Negative Pinkish Negative
5 minutes Slight trace Negative Negative Brown Negative
Immediate Negative Negative Negative Pink Negative
2 1 minute Negative Negative Negative Pink Negative
5 minutes Negative Negative Negative Brown Negative
Immediate Slight trace Negative Negative Decided pink Negative
3 1 minute Slight trace Negative Negative Distinct pink Negative
5 minutes Trace Very slight Negative Brown Negative
pink
Immediate Negative Negative Negative Pinkish Negative
4 1 minute Negative Negative Negative Brownish Negative
5 minutes Negative Negative Negative Brown Negative
SERIES C.
(Heated for 20 minutes at 208 to 209°F.—97.8 to 98.3°C.)
Immediate Negative Negative Negative Brownish Negative
1 1 minute Negative Negative Negative Brown Negative
5 minutes Negative Negative Negative Brown Negative
Immediate Negative Negative Negative Pinkish Negative
2 1 minute Negative Negative Negative Pinkish Negative
5 minutes Negative Negative Negative Brown Negative
Immediate Slight trace Negative Negative Decided pink Negative
3 1 minute Positive Very slight Negative Pink Negative
pink
5 minutes Positive Very slight Negative Brown Negative
pink
Immediate Slight trace Negative Negative Pinkish Negative
rown
4 1 minute Positive Negative Negative Brown Negative
5 minutes Positive Negative Negative Brown Negative
SERIES X.
(Original Tupelo honey plus 20% of commercial invert sugar sirup prepared according
to method of Herzfeld*.)
Immediate Positive Negative Negative No report Positive
X 1 minute Positive Very slight
pink Negative No report _ Positive
5 minutes Positive Very slight
pink Negative No report _ Positive
*U. S. Bur. Chem. Bull. 110: (1908), 64.
Examination of the results shows:
Resorcin test.—Four of the collaborators obtained negative results in every case.
One of them (Webre) obtained doubtful results in several cases and slight traces in
several cases. In view of the fact that he reports one as “‘pink-positive”’ it would appear
1922] SHERWOOD: DETECTION OF ARTIFICIAL INVERT SUGAR IN HONEY 435
that his “‘slight traces” refer to pink color. As noted previously, this does not con-
stitute a positive test. It is of note that, in the sample to which invert sugar was
added, Church, Wilson and Fuller obtained negative results.
Aniline chloride test—Three of the collaborators obtained negative results in every
case. One of them (Webre) obtained positive results in Sample 4, Series A (heated for
1 hour at 160°F.) and in Sample 4, Series C, (heated for 20 minutes at 208-209°F.)
but obtained negative results in Sample 4, Series B (heated for 14 hour at 180°F.).
He also reports positive results in Sample 3, Series C (heated for 20 minutes at 208-
209°F.), after standing one minute. Fuller obtained traces of pink in several cases, but
this does not constitute a positive test. Webre stated that the reaction taking place
in five minutes in the case of dark-colored samples does not develop sufficient color to
permit of accurate conclusions. Church stated that the very slight pink colors noted
could be detected only in thin layers, and that the test is scarcely sharp enough to
justify condemning a honey on the strength of this determination alone. It is of note
that in the sample to which invert sugar was added Church and Wilson obtained nega-
tive results.
CONCLUSIONS.
In the case of honeys heated at temperatures which would prevail in
the ordinary commercial handling of this product, neither the resorcin
nor the aniline chloride test affords results that can be construed to
indicate the presence of commercial invert sugar sirup. Thus, a posi-
tive result with either test serves to indicate the presence of a foreign
substance. It is considered that an insufficient number of reports have
been obtained—though efforts were made to secure the assistance of a
larger number of collaborators—to justify the above conclusions being
regarded as final, and it is recommended that the work be repeated.
If this is done, the directions sent to the collaborators should include a
more complete and detailed description of the technique and of the
color tints than is given in the official methods'. In spite of detailed
description, it is obvious that the operator must have had experience in
order to obtain correct results.
Referring to the possibility of obtaining a positive test in the case of
a honey that has been grossly overheated, the associate referee wishes
to present the question of whether the term “honey”? may be applied
properly to a product resulting from grossly overheating honey with
resulting loss of flavor, darkening of color and production of furfural.
1 Assoc. Official Agr. Chemists, Methods, 1920, 112.
436 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 3
REPORT ON MAPLE PRODUCTS.
By C. H. Jones (Agricultural Experiment Station, Burlington, Vt.),
Referee.
Your referee has had no opportunity during the past year to do any
cooperative work on the Canadian lead number and the conductivity
value of maple products.
Both procedures have been printed?.
Your referee recommends that these methods be not adopted as
tentative at this time.
REPORT ON MALTOSE PRODUCTS.
By O. 8. Keener (Bureau of Chemistry, Washington, D. C.), Associate
Referee.
The work on maltose in recent years has been in connection with the
determination of maltose and dextrine in beer. However, since maltose
products may contain both dextrose and maltose, in addition to dex-
trine, it seems very desirable that a method for the determination of
both these sugars in the presence of dextrine be adopted.
A study of the literature for available methods indicated the follow-
ing possibilities:
I. The use of maltase.
II. The use of maltase-free yeasts.
III. The use of ordinary yeasts (present provisional method).
IV. The determination of dextrine by precipitation with alcohol.
The use of maltase is prohibited, for the present, by the lack of an
available supply of this enzyme. The difficulty of maintaining maltase-
free strains of yeast, together with the care and time required in their
use, also would seem to eliminate this method from ordinary use for
the present. The use of ordinary yeast is unsatisfactory from a number
of standpoints. Consequently it was decided to investigate further
the determination of dextrine by precipitation with alcohol, with the
subsequent determination of sugars in the filtrate by the usual com-
bination of polariscopic and copper reduction methods.
To this end, considerable experimental work was done to ascertain
the best conditions for the precipitation of the dextrine. This work
has been practically completed, and the method is about ready for
distribution to the collaborators.
It is recommended that this work be continued for another year.
1 Presented by O. S. Keener.
2 J. Assoc. Official Agr. Chemists., 1921, 4: 428.
1922] BREWSTER: REPORT ON SUGAR-HOUSE PRODUCTS 437
REPORT ON SUGAR-HOUSE PRODUCTS".
By J. F. Brewster (Louisiana Sugar Experiment Station, New Orleans,
La.), Associate Referee.
Pursuant to the recommendations? made by the Associate Referee on
Sugar-House Products for 1919, F. W. Zerban, the cooperative work
on ash determination was continued.
Samples of cane sirup, first molasses and final molasses were sent to
a number of chemists who had signified their willingness to cooperate,
but, up to the time of filing this report, an insufficient number of results
had been returned to enable the associate referee to draw conclusions.
In submitting the samples to the various chemists it was recommended
that in making the direct ash determinations four temperatures be
tried—475°, 500°, 525° and 550°C. These temperatures range from the
dullest red heat at about 475° to a very decided red at 550°. Both
methods I and II of Zerban’s report? were recommended to be tried.
Only one complete set of results is at hand. These were submitted
by W. G. Raines, Jr., of the Louisiana Sugar Experiment Station.
Many collaborators were compelled to forego cooperation on this phase
of the work because their laboratories did not possess the necessary
pyrometers or furnaces for careful measurement and control of tem-
perature.
Three sets of results on sulfate ash were received, but since the object
of making these determinations is to work out a factor for deduction
by comparison with direct ash, the purpose will not be well served
until many more results by both methods are at hand.
It is hoped that sufficient data from which definite conclusions may
be drawn will be received from other collaborators before the next
report is in order.
It should be pointed out that in shipping samples of sirup or molasses
deterioration is fairly certain to follow. The proper time for cooperative
work upon these materials is, therefore, during cold weather. The
associate referee has a supply of identical samples in storage and is
desirous of obtaining more collaborators.
RECOMMENDATIONS.
It is recommended—
(1) That the study of ash determination by both the direct and
sulfate methods be continued.
(2) That a comparative study of methods for the determination of
specific gravity and of total solids of molasses be undertaken.
1 Presented by O. S. Keener.
2 J. Assoc. Official Agr. Chemists, 1921, 4: 451.
5 Ibid., 444.
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FIRST DAY.
MONDAY—AFTERNOON SESSION.
REPORT ON FERTILIZERS.
By R. N. Brackett (Clemson Agricultural College, Clemson College,
S. C.), Referee.
The work for 1921 followed the lines of former recommendations,
and the results are contained in the reports of the different referees,
together with their recommendations.
Nothing very startling developed this year. The nervous condition
of the consumer about borax in fertilizers seems to have died a natural
death, like so many other scares in the past; or perhaps confidence has
been restored by the reappearance of foreign potash on our markets.
Like so many ills, this borax scare served a good purpose, both in stimu-
lating work and improving our method of approach—through general
referees.
A paper, entitled ““The Development of Accuracy in Fertilizer Analysis
and Some Pitfalls in Methods”, by P. McG. Shuey, read before the
Fertilizer Division of the American Chemical Society, may be worthy
of consideration. It refers to the official volumetric method for the
determination of phosphoric acid in fertilizers? and also to the details
of the official method for determining nitrogen when nitrates are present
in fertilizers’. The suggestion pertaining to the latter method is in
complete accord with your referee’s experience and practice.
J. H. Mitchell, who had planned to cooperate in the work on borax
in fertilizers, took up with two of the senior students of Clemson Col-
lege, as a thesis problem, a comparison of the Ross-Deemer, the Bartlett,
and the Pope-Ross methods of analysis, and, with another student,
the determination of nitrogen in nitrates in which the Devarda method
was tried out. A few comments on the results of this work will be
given by the associate referee.
Last year Arthur W. Clark, Agricultural Experiment Station, Geneva,
N. Y., presented a paper before this association, entitled “A Method
for the Determination of Phosphoric Acid’’*. No recommendation was
made for further investigation, but Mitchell took this also as a thesis
problem. The results were not promising for the application of the
method in routine work, though fairly accurate results may be obtained
under the proper conditions of manipulation.
1 Am. Fertilizer, 1921, 55: 52.
eee Agr. Chemists, Methods, 1920, 3.
id, 7.
‘J. Assoc. Official Agr. Chemists, 1921, 5: 103.
439
440 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON THE DETERMINATION OF BORIC ACID IN
FERTILIZERS AND FERTILIZER MATERIALS.
By Wiitram H. Ross (Bureau of Soils, Washington, D. C.), Associate
Referee.
A summary of results obtained in a comparative study by eight
collaborators of three quantitative methods for determining water-
soluble boric acid as borax in fertilizers and fertilizer materials! was
given last year. After the work was completed a modified distillation
method which appeared to offer some advantages over other distillation
methods was proposed by J. M. Bartlett? of the Maine Experiment
Station. In accordarze with the recommendations that the Ross-
Deemer? method be adopted as a tentative method and that further
work be done in comparing this method with the Bartlett distillation
method, a collaborative study of the relative merits of the two methods
in question was undertaken.
PREPARATION OF SAMPLES FOR COLLABORATIVE WORK,
The samples submitted to the different collaborators consisted of
three mixed fertilizer samples and three of potash salts. Sample No. 1
was a 5-8-5 fertilizer, the same as No. 3 of last year, and contained 0.1
per cent. of anhydrous borax. Sample No. 2 was the same as No. 1
with 0.5 per cent of borax. Sample No. 3 contained 1.15 per cent of
borax and was prepared from a 5-10-0 fertilizer and a mixture of salts
in imitation of crude Searles Lake potash. Samples Nos. 4, 5 and 6
were made of borax-free salts in imitation, respectively, of potash manure
salts, commercial Chilean nitrate and the salts in the brine of Searles
Lake. No borax was added to Sample No. 4; 0.5 per cent was added
to No. 5; and 3.0 per cent was added to No. 6.
The borax used was prepared by adding a known amount of boric
acid of a high degree of purity to a solution of an equivalent amount of
pure sodium carbonate. The solution was then evaporated on a water
bath, dried at 110°, weighed and ground to pass a 175-mesh sieve.
Knowing the weight of the boric acid taken and of the product finally
obtained, it could then be calculated how much of the product would
have to be added to a fertilizer to give a borax content equivalent to
any desired percentage of anhydrous borax. As a check against any
possible loss of borax in the course of its preparation, weighed portions
of the recovered product and of the boric acid from which it was pre-
pared were titrated against the same standard alkali.
1 J. Assoc. Official Agr. Chemists, 1921, 5: 83.
2 Thid., 1921, 5: 90.
3 [hid., 327; Am. Ferlilizer, 1920, 52: 62.
—_
1922] ROSS: DETERMINATION OF BORIC ACID IN FERTILIZERS 44]
INSTRUCTIONS TO COLLABORATORS.
A detailed account of each method was forwarded with the samples
to each collaborator, and it was requested that each analyst submit a
report on completing the work indicating the method which, in his
judgment, gave most accurate results and which was considered most
rapid for each sample analyzed, if applied to routine analysis. The
reports received from ten collaborators are summarized in Table 1.
TaBLe 1.
Determination of boric acid in mixed fertilizers and fertilizer materials.
BORIC ACID EXPRESSED AS ANHYDROUS BORAX
Sample Sample Sample Sample Sample
No. 1 No. 2 No. 3 No. 4 No. 5
ANALYST Borax, Borax, Borax, Borax, Borax,
0.10% 0.50 % 1.15% none 0.50 %
eas = Sales | (eal ee
}a8| Ss | e8|s | e8|s afl 3
=a a =O); |}|S8/ 8 =O a)
|
per | per | per | per | per | per | per | per | per | per |
cent | cent | cent | cent | cent | cent | cent | cent | cent | cent
| 1
C. A. Butt, International
Agricultural Corporation | | |
Atlanta, Ga e222 5. =. 0.09} 0.07| 0.45) 0.43} 1.31) 1.15) 0.00) 0.01) 0.48) 0.48 2.85) 2.75
L. W. Willis, Agricultural
Experiment Station,
New Brunswick, N. J.. .| 0.09] 0.10) 0.36) 0.45) 1.00) 1.14/ 0.06)... .| 0.50)... .| 2.84)...
H. B. McDonnell, Agri-
cultural Experiment
Station, College Park,
INTO ha eens kre oe 0.10} 0.14] 0.40) 0.50) 0.91) 1.06) 0.04) 0.05) 0.57) 0.53) 2.95) 2.93
R. M. Jones, Bureau of
Soils, Washington, D. C. | 0.12| 0.19) 0.46 0.46) 1.10} 1.26) 0.00} 0.00) 0.49) 0.51) 2.88) 2.67
William Hazen, Bureau of
Soils, Washington, D.C. | 0.13) 0.10) 0.48) 0.43) 1.15) 1.13) 0.01) 0.02| 0.50) 0.47) 3.00) 2.77
Millard G. Moore, Agri-
cultural Experiment
Station, Geneva, N. Y..| 0.14| 0.09) 0.44} 0.42) 0.88} 1.06) 0.00) 0.00) 0.48) 0.44) 2.84) 2.65
Ethel Schram, Armour &
Co., Chicago, Ill....... 0.11) 0.06) 0.44) 0.57) 1.12 0.29) 0.06) 0.01) 0.47] 0.50} 2.86 2.90
E. R. Tobey, Agricultural
Experiment Station,
Wronol Mer AP. 0.09} 0.09) 0.40) 0.39) 1.05) 0.99} 0.00) 0.00) 0.53) 0.44) 2.81) 2.67
C. H. White, Agricultural
Experiment Station,
Orono? MeS9S 3. e528 0.07! 0.09) 0.29) 0.42} 0.80) 1.07| 0.00) 0.00) 0.49) 0.45) 3.01) 2.57
W. C. Weltman, Agri-
cultural Experiment
Station, Orono, Me... . .| 0.07) 0.06| 0.43) 0.40) 1.02) 1.02| 0.00) 0.00) 0.50) 0.61) 2.81| 2.88
SV EEARE cet) See es 0.10} 0.10) 0.42| 0.45] 1.03) 1.02| 0.02) 0.01) 0.50) 0.49) 2.89) 2.75
DISCUSSION.
The averages of the results reported by the different collaborators
show that so far as accuracy is concerned there is no choice between the
442 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
two methods. In the matter of rapidity it appears that neither method
is superior or equally suitable for all classes of materials. The Bartlett
method is more convenient for the analysis of materials high in soluble
phosphates or organic matter relative to the boric acid, while the Ross-
Deemer method is preferred for materials which are relatively low in
these constituents. A summary of the reports made by the different
collaborators on the relative rapidity of the two methods is given in
Table 2. One of the collaborators made no comments on either method;
two expressed no preference in the case of Sample No. 4; and one made
no choice in the case of Sample No. 5.
TABLE 2.
Summary of reports of collaborators on relative rapidity of methods.
NUMBER OF COLLABORATORS REPORTING IN FAVOR OF
METHOD OF—
SAMPLE NO.
Ross-Deemer Bartlett
OoPpwnr
DNONNH
eS eS ea)
In commenting on the combined reports of the different collaborators,
Bartlett called attention to the advantage of a chemist having a choice
of two methods of entirely different procedure but of equal accuracy,
and of being able to check one against the other on special occasions,
as when testimony is to be given in court.
It may be emphasized, as was pointed out by Butt, that the Bartlett
method is likely to give acid-soluble boric acid while the Ross-Deemer
method gives only water-soluble boric acid. The samples submitted
to the collaborators contained borax only, and the results with both
methods therefore agree, but this may not be true in the case of samples
containing both soluble and insoluble boric acid, unless the procedure of
analysis is modified to give water-soluble or acid-soluble boric acid, as
the case may require.
RECOMMENDATIONS.
It is reeommended—
(1) That the Bartlett method be adopted as a tentative method for
the determination of boric acid in fertilizers and fertilizer materials on
account of its special adaptation to the analysis of samples which are
relatively high in soluble phosphates or organic matter.
(2) That the Ross-Deemer method be retained as a tentative method
for the determination of water-soluble boric acid in fertilizers and ferti-
1922] ROBINSON: PREPARATION OF NEUTRAL AMMONIUM CITRATE 443
lizer materials on account of its special adaptation to the analysis of
samples which are low in soluble phosphates and organic matter relative
to the boric acid.
(3) That further work be done on both methods recommended as
tentative to determine the effect of insoluble boric acid and to study any
modifications necessary to make both methods applicable to the de-
termination of water-soluble, acid-soluble or total boric acid, as the
case may require.
REPORT ON THE PREPARATION OF A NEUTRAL SOLUTION
OF AMMONIUM CITRATE.
By C.S. Rosrnson (Agricultural Experiment Station, E. Lansing, Mich.),
Associate Referee.
In accordance with the recommendation of the association that the
colorimetric method “‘be given further study, with collaboration, with a
view to adoption in 1921”, the associate referee asked each collaborator
TABLE 1.
Reaction and composition of ammonium citrate solutions.
OFFICIAL METHOD PROPOSED METHOD
Ratio of ammonia to Ratio of ammonia to
COLLABORATOR anhydrous citric acid anhydrous citric acid
pH pH
Referee | Collabora- Referee | Collabora-
tor tor
R. F. Gardiner, Bureau of Soils,
Wiashmetons Gis.) ss .nes ss TY eB ELON eae oa GiSie els: 760i eeceeee
W.H. Strowd, Department of Agri-
culture, Madison, Wis.. 7.8 110334 03210)'| ees Gel | (oerec| eae oneal emer rc
R. D. Caldwell, Armour Fertilizer | 6.4 1:3.946 | 1:3.841 || 7.3 1:3.749 | 1:3.694
Works, Atlanta, Ga.. 6.8 1:3.805 | 1:3.709 || 7.4 1:3.756 | 1:3.690
E. E. Vanatta, Agricultural Experi- 6.6+] 1:3.838 | 1:3.690 || 6.6 1:3.859 | 1:3.620
ment Station, Columbia, Mo... .| 6.7 1:3.797 | 1:3.580 || 6.7+| 1:3.805 | 1:3.590
G. Hart. Agricultural Department,
sRallahassee: Blas: s...+50< <2 <a: 6.7 SES TON ets sere larrceceea llotave icbelsvevcil eins ces cieke
P. H. Wessels, Agricultural Experi-
ment Station, Kingston, Re Lecs| idee) lied AGS 1 os tt COS IES 7G) Gl eee
A. P. Kerr, Agricultural Experi- | 7.8 1:3.767 | 1:3.787 || 7.0 1:3.814 | 1:3.797
ment Station, Baton Rouge, La. 7.0+] 1:3.809 | 1:3.797
E. G. Proulx, State Chemist, La- | 6.6 USUI lee ob G:8=FIMIcSS35) |. «ech
favetlenindeetis.. eee eee 6.6 138954 ea. eee GSS BLES SST aecee
W.. D. Richardson, Swift & Co., | 7.2 1:3.813 | 1:3.777 || 7.0—| 1:3.826 | 1:3.759
CGlitrezripa 1] DE SR nee Aer 7.0 1:3.823 | 1:3.776 || 7.0—| 1:3.819 | 1:3.762
Armour & Co., New Orleans, La.. .| 6.2 1:4.005 | 1:3.665 || 6.8 1:3.836 | 1:3.837
6.2 1:4.007 | 1:3.732 || 6.8 1:3.831 | 1:3.866
JW. W ecllogg, Department of Agri- | 7.4—|] 1:3.776|....... 6.9 TS tSS0u| pe erie
culture, Haaebare, Pa Sra tn cede ee —|PUeastOU |S ve ce thee 6.9 USS ZO lee eae
J. H. Parkins, F. S. Royster Guano | 7.3 M3742 | Peace WE hese asl ecco el ak ras
GOP Nortolics, VOs 2 a5 0.0 cicbaes overs 7.3 Me SETS ese Secs: oss! [Wea cuciall Reccogbetererel | ereceiernekoes
LF. Schmelzer, Armour & Co.,/6.9 | 1:3.799 | 1:3.779 || 7.6 1:3.748 | 1:3.729
Giro me nN Veit der ovsrides ersrevolens 1? 1:3.744 | 1:3.759 || 7.6 1:3.743 | 1:3.809
444 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
to submit samples of four solutions. Two of these were to be prepared
by an official method and two by the proposed colorimetric method.
Thirteen chemists sent in solutions prepared by one or the other of the
official methods, and eleven submitted samples made up by the pro-
posed method. One of the sets made by the proposed method was
discarded because the proper standard had not been used. One set
of solutions neutralized to litmus paper was also received. The reactions
of the solutions were measured colorimetrically against standards which
had been checked electrometrically, and the ratios of ammonia to citric
acid were determined by the formaldehyde titration method. The re-
sults are shown in the table and chart.
It is at once apparent that the colorimetric method gives, as a rule,
solutions more nearly neutral than do the official methods. Not only
are a greater number of truly neutral solutions prepared by the new
method than by the official methods, but the range of variation from
the neutral point is much narrower. Of the twenty-one solutions pre-
pared by the official methods only seven (33 per cent) come within
a range of pu 6.8—7.2 as compared with a total of twelve (67 per cent)
of those prepared by the new method. Only three solutions (14 per
cent) of those prepared by the official methods were within one point
of neutrality, while seven (39 per cent) of those prepared by the colori-
metric method were actually neutral within this range of error.
Proposed Method Official Method
Comparison oF Reactions or AMmontum CITRATE
Sotutions Prepanep By THE OrriciaL AND Proposep Mernops.
Unfortunately, complete data on the particular official method used
by each collaborator are not available so that no comparison can be
made between the results with corallin! and with the alcoholic calcium
chloride method*. However, as one analyst only reported the use of
1 Assoc. Official Agr. Chemists, Methods, 1920, 4, (i).
2 Ibid., (2).
1922] ROBINSON: PREPARATION OF NEUTRAL AMMONIUM CITRATE 445
the latter, while several stated that they had used the former, it may be
assumed that but few laboratories use the longer and more complicated
procedure, which, the writer is convinced, has nothing to recommend its
retention as an official method.
One point was brought to the attention of the writer in connection
with this work which should be considered by the association before
the subject is closed. This is the method of analysis to be used in
checking up the composition of ammonium citrate solutions. Several
modifications are used, some of which are not reliable. This accounts
for some of the differences in the results of the analyses by the collabora-
tors and the referee. Changes in the composition of the solutions
owing to the loss of ammonia or solution of alkali from the glass con-
tainers are factors which influence the results in some cases.
The results of a study of this subject have been published elsewhere!
as the writer considered that they dealt with a different phase of the
citrate question than that covered by the recommendation of the asso-
ciation.
RECOMMENDATIONS.
It is recommended—
(1) That a neutral solution of ammonium citrate be considered as
one in which the ratio of ammonia to anhydrous citric acid is as
1:3.794+0.02, and that it shall have a reaction corresponding to a
pH of 7.0+0.2.
(2) That that section of the official methods dealing with the pre-
paration of neutral solutions of ammonium citrate? be changed to read
as follows:
12 REAGENTS.
In addition to the reagents described under 4 and 7 prepare ammonium citrate
solution by the following method:
Ammonium citrate solution—For every liter of solution required dissolve 172.00
grams of anhydrous or 188.13 grams of crystallized citric acid in approximately 700 cc.
of water; nearly neutralize with ammonium hydroxide; cool; measure the volume of
solution or make it up to a convenient volume, taking care to keep the density above
1.09; make exactly neutral, testing as follows: With a pipet transfer 5 cc. of the citrate
solution to a test tube (preferably 7x74 inches) and dilute to 20 cc. with distilled
water. Add from a dropping bottle 5 drops of a 0.08% solution of phenol red indicator.
From a buret run in standard ammonia solution until the color approximates that of a
standard buffer solution having a pu of 7.0 (prepared by mixing 50 cc. of 0.2M di-
hydrogen potassium phosphate solution and 29.63 cc. of 0.2N sodium hydroxide solu-
tion and making up to 200 cc.) contained in a similar test tube and with the same con-
centration of indicator. Complete the process by carefully adding the standard am-
monia solution in smal! amounts and comparing the colors in a comparator. From
the amount cf ammonia solution required to produce in the sample a color which exactly
matches that of the standard, calculate the amount required to neutralize the rest of
the solution.
1 J. Ind. Eng. Chem., 1922, 14: 429.
2 Assoc. Official Agr. Chemists, Methuds, 1920, 4.
446 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Add this calculated amount of ammonia to the original solution and check its reaction
against that of the neutral standard, using the technique described above. If the
colors match, dilute the solution to a density of 1.09 at 20°.
Finally check the composition of the solution by determining the ratio of ammonia
to citric acid by analysis.
(3) That the methods of analysis of ammonium citrate solutions be
studied.
SOME EXPERIENCES WITH THE ALKALINE
PERMANGANATE METHOD".
By C. S. Rosrnson and O. B. Winters (Agricultural Experiment
Station, E. Lansing, Mich.).
Realizing that the alkaline permanganate method? for the measure-
ment of the quality of organic nitrogen in fertilizers had certain inherent
faults, the writers attempted some time ago so to modify it as to over-
come these defects. After spending considerable time, it was con-
cluded that no progress could be made by simple hit-and-miss trials,
but that some fundamental knowledge of the actual chemical factors
involved in availability and its measurement must first be gained.
Consequently, attempts to develop a modification of the permanganate
method were discontinued, and a study was made of the actual effect of
the procedure ordinarily followed upon chemical substances of more or
less definite constitution. The results of the preliminary work are
reported merely to have them on record for the benefit of anyone who
may be tempted to try the same line of attack. It is only fair to state
in this connection that similar work had been done by the originator
of the method, C. H. Jones, and that his conclusions were verified by
the present writers.
It is probably a safe assumption that the organic compounds of
greatest importance in fertilizers are of protein origin. From the
writers’ knowledge of the chemistry of such substances the action of
alkaline permanganate solution upon them may be divided into two
steps. The first, the action of the alkali, i. e. the hydroxyl ions, will
result in a hydrolytic cleavage of the protein compounds producing
ultimately amino acids and acid amides. An analogous action takes
place in the soil under the influence of bacterial and chemical agents.
Another result of the alkali in the reagent employed is the decompo-
sition of a portion of the acid amides present with the liberation of
ammonia. These compounds, i. e. the acid amides, furnish practically
all of the ammonia liberated directly by the action of the alkali, only
! Journal Article No. 21 from the Chemical Laboratory of the Michigan Agricultural College Experiment
Station. Published by permission of the Director of the Experiment Station.
2 Assoc. Official Agricultural Chemists, Methods, 1920, 11.
1922| ROBINSON: EXPERIENCES WITH PERMANGANATE METHOD 447
a small portion being given off by the other compounds as the result of
the action of alkali alone. In short, the alkali of the permanganate
reagent breaks down the complex organic nitrogenous compounds into
simpler ones, i. e. amino acids and acid amides, and converts a portion
of the latter into ammonia.
The second step in the process (which, of course, goes on simultane-
ously with the first) is the conversion of a fraction of the amino-acid
nitrogen formed by the alkali into ammonia. The ultimate effect then
of both alkali and permanganate is the production of ammonia which is
used as a measure of the value of the material under examination.
No doubt it is possible with the alkaline permanganate reagent to
measure the total amounts of acid amide and amino-acid nitrogen
obtainable from any substance if treatment is continued long enough.
All of this nitrogen can be used by plants for food purposes, in some cases
directly and in others indirectly after conversion into ammonia. Any
nitrogen which can be so converted must be considered as being poten-
tially available. Its measurement presents no problem. The diffi-
culty lies in the determination of that portion of this potentially avail-
able fraction which will be made available during a growing season.
The simplest assumption is that this is determined by the rate at
which potentially available nitrogen is converted into amino acids,
acid amides and ammonia. This rate would be different for different
materials whose availability would vary directly with it. If this assump-
tion is justified, then it should be possible to find some set of laboratory
conditions under which organic nitrogenous materials would be de-
composed at the same relative rates as they are in the soil. A method
based upon this procedure would involve the measurement of a definite
property common to all of the materials to which it would be applied.
This the present method does not do, although it is only under such
conditions that results can be obtained which are properly comparable.
Two values offer themselves naturally for consideration: (1) The time
required for the ammonification of a selected fraction of the potentially
available portion; and (2) the fraction of the nitrogen ammonified in a
given time. The value of the second factor is that which the present
method attempts to measure. In some cases it actually does this while
in others it does not. With materials which do not decolorize the
permanganate the results obtained show the nitrogen ammonified during
the time required for the determination. With cottonseed meal, peat
and other substances which do decolorize the solution the meaning of
the results is quite different since the ammonia produced by the second
step of the process, as outlined above, is materially reduced. With such
materials the principal effect is that of the alkali, the permanganate
being removed from the sphere of action early in the process. Hence,
in effect, the results of two entirely different reagents are compared
448 ASSOCIATION OF OFFICIAL AGRICULTURAL @€HEMISTS [Vol. V, No. 4
when an attempt is made to compare the figures obtained with these
two classes of materials, i. e. those which do not and those which do
decolorize the permanganate. In reality, values obtained for materials
of the latter class are low, not because of their poor quality, but because
of the manner in which they are treated.
If conditions are so altered that the permanganate is not decolorized,
the second group of substances gives an entirely different picture. In
Table 1 are shown the values for the active insoluble nitrogen in cotton-
seed meal and peat, (1) as obtained by the official method, and (2) by
substituting for the samples containing 50 milligrams of nitrogen, ones
so small that the permanganate was not decolorized.
TABLE 1.
Comparison of the action of permanganate on varying samples of peal and cottonseed meal.
AMINO NITROGEN
TOTAL oe
NITROGEN
AMIDE NITROGEN
per cent per cent
Cottonseed meal—full sample..................- A500. o- seil\ lg wheat pea
Cottonseed meal—half sample..................- 70.60 68.42
Peat—follisample: fysayire vata), 7. Sa ids Ge. Be 22:32>)1:) |e \iRepaaees
Peat—one-eighth sample.................008000: 66.00 59.79
It is evident that when judged by the same standards the differences
between high- and low-grade nitrogen are greatly diminished.
A second point of fundamental importance in the use of the alkaline
permanganate method is the fact that the concentration of the reagents,
especially the alkali, is constantly increasing, until, at the end of the
distillation, the speed of any reaction not already completed is pre-
sumably high. Thus any variation in time will produce a correspond-
ing variation in results. Yet with the tendency on the part of the
sample to foam badly, the digestion and distillation periods are fre-
quently lengthened far beyond the recommended 90 minutes. The
amounts of nitrogen in the last portions of the distillates from several
materials are shown in Table 2.
As it is dificult to gage the distillate closer than 10-15 cc. with the
ordinary sized flasks used in this procedure, i. e. 500 cc. Kjeldahl and
300 ce. receiving flasks, the above figures represent possible errors in
every-day practice.
From the above considerations it seemed advisable to modify the
method with respect to the following points:
(1) The size sample selected should be such that an excess of per-
manganate would always be present.
(2) The final concentration of reagents should be such that reason-
1922] ROBINSON: EXPERIENCES WITH PERMANGANATE METHOD 449
TABLE 2.
Ammonia given off in the last portions of the distillate in the alkaline permanganate method.
Sample* | Sample* | Sample* | Samplet Samplet
No. 23 No. 24 No. 28 No. 43 No. 45
per cent per cent per cent per cent per cent
Motalimitropenys See eke se welsh es 5s 14.01 14.05 2.76 2.48 3.10
Insoluble nitrogen.................. 12.97 13.25 2.52 1.66 1.31
Insoluble nitrogen (Per cent of total
MIMO SEM) stan: 3 Mn ss sicie + ys. he ws 92.57 94.30 91.30 66.93 42.26
Active insoluble nitrogen........... 9.93 10.53 0.92 gh 0.52
Active insoluble nitrogen (Per cent of
totalinitrogen)) Sn wees san sis <. 70.87 74.96 33.34 44.75 16.77
Active insoluble nitrogen (Per cent of
insoluble nitrogen)................ 76.56 79.47 36.51 66.86 39.69
Nitrogen in distillate................ 0.62 0.40 0.13 0.07 0.06
Nitrogen in distillate (Per cent of total
MEENOPED) Peete Gevalelkait assole Gs 215-06 4.43 2.85 4.71 2.82 1.93
Nitrogen in distillate (Per cent of in-
SOluble NnItTOPeM) F -heeisi rete oe. 4.78 3.02 5.16 4.22 4.58
*Amount of distillate, 15 cc.
tAmount of distillate, 12 cc.
tAmount of distillate, 10 cc.
able variations in the time of distillation and the amount of distillate
would not produce significant variations in the results.
With this in view permanganate solutions of various strengths were
used; the processes were carried out for different lengths of time and
different sized samples were taken. No set of conditions was found,
however, that seemed to give any promise of success. The following
procedure and the results obtained with it are typical:
Weigh a 14- (or 14- where the material is high in nitrogen) gram sample into a funnel
containing a 12.5 cm. filter paper and wash with 250 cc. of distilled water. Transfer
the insoluble residue to a 500 cc. Kjeldahl flask. Add 300 cc. of 0.5N alkaline per-
manganate solution (containing 15.8 grams of potassium permanganate and 20 grams
of sodium hydroxide per liter). Heat to boiling in about 20 minutes, digest 1 hour and
distil off 150 cc. in 45 minutes.
It was found that most of the ammonia came over in the first 150 cc.
That in the second 150 cc. came over slowly and hence a small variation
in the conditions of distillation produced but small variations in the
results.
The results show that, as was pointed out previously, changes in the
relative amounts of sample and solution tend to exert a general leveling
effect on the values found, diminishing the range of differences between
high- and low-grade materials.
The authors’ experiences led to two conclusions regarding the future
development of methods for determining the availability of organic
nitrogen: (1) That any new method must be built upon an entirely new
foundation for which more fundamental chemical knowledge of the
factors involved in availability is necessary; and (2) that it is highly
450 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 3.
Comparative results with official and modified alkaline permanganate methods.
INSOLUBLE NITROGEN, | | INSOLUBLE NITROGEN,
Sample No. ACTIVE FORM | Sample No. ACTIVE FORM
Official Method |Modified Method Official Method |Modified Method
per cent per cent per cent per cent
28 34.52 53-17 hi 44 54.90 59.31
27 35.16 50.64 | 16 57.88 57.18
45 35.88 57.25 36 58.22 57.54
21 44.08 44.78 46 59.94 61.62
19 46.56 57.20 43 62.05 49.40
31 48.99 47.91 35 65.97 55.97
29 51.72 49.60 32 67.59 55.02
30 54.23 53.52 24 69.21 58.11
desirable that more systematic vegetation experiments be carried on,
thus giving more reliable standards upon which to base conclusions
regarding the values of any methods proposed. At the present time
too few data on the relative actual values of various types of organic
materials are available to make it safe to say that one method does and
another does not give a fair estimate of their relative grades.
0
SAMALE N28. ~ 28 27 PS hel, ? 3 22 30 4# 1/6 36 Fé O35) IF SR Aas
Comparative Resuuts wita OrrictaL AND Mopiriep ALKALINE PeRMANGANATE MerTHops.
REPORT ON NITROGEN.
By I. K. Puetes (Bureau of Chemistry, Washington, D. C.), Associate
Referee on Nitrogen in Fertilizers.
A recommendation made by the association in 1920 directed the asso-
ciate referee to make a study of the Devarda alloy method as applied
to the determination of nitrate nitrogen in potassium and sodium
nitrate. Owing to the pressure of other work, one sample only of care-
fully prepared potassium nitrate with a sufficient amount of Devarda
alloy for conducting the work was sent to thirty chemists who had
signified their willingness to cooperate. Six reports were received.
1922] PHELPS: REPORT ON NITROGEN 451
INSTRUCTIONS TO COLLABORATORS.
REAGENTS.
(a) Devarda alloy, specially prepared.
(b) 0.2N standardized acid.
(C) 0.1N standardized alkali.
(d) Methyl red indicator—Dissolve 0.02 gram in 100 cc. of hot water (10 drops for
each titration).
DETERMINATION.
Into an 800 cc. Kjeldahl flask, measure 300 cc. of water, 3 grams of alloyand 3-5cc.
of sodium hydroxide solution (sp. gr. 1.453). Connect the flask at once with a Kjeldahl
distilling apparatus fitted with a Davisson scrubber! or other suitable scrubbing bulb,
preferably of Pyrex glass, into which 20-30 cc. of water have been drawn, and distil.
During the process of distillation the tip of the condenser should always extend beneath
the surface of the standard acid soluton, and the reducton of the nitrate should be
carried on synchronously with the distillation. Regulate the boiling so that approxi-
mately 250 cc. of the distillate will be collected in the required time for each series of
experiments. When the distillation is half completed it is recommended that part of
the solution in the scrubber be sucked back into the distillation flask, allowing 10-20
cc. to remain in the bulb, this being accomplished by removing the flame or holding
the flask out of place and applying a damp cloth. This removes the danger of the
liquid in the bulb splashing over into the condenser, and by reducing the volume of
liquid in the bulb, facilitates the passing of the last traces of ammonia into the receiving
flask.
EXPERIMENTS.
I. Three sets of blanks: (A) 34 of an hour, (B) 1 hour and (C) 114 hours. First
connect the flasks to the condenser by means of scrubbing bulb but omit sample,
start the reduction, distil slowly and turn the flames up after 10 minutes so that 250
ce. of distillate are collected in Set A in 34 of an hour, Set B in 1 hour and Set C in 114
hours.
II.—Dissolve exactly 4 grams of potassium nitrate in distilled water and dilute at
standard temperature to 500 cc. in a volumetric flask. Mix thoroughly and transfer
25 cc. portions of this solution to the 800 cc. Kjeldahl flasks by means of an accurate
pipet. With this sample repeat all the steps under Procedure I.
III.—Dissolve 10 grams of potassium nitrate in 500 cc. of water as above and take
25 ec. portions of this solution. Repeat as in Procedure II.
IV.—Repeat six of Procedure III, but bring sample to boiling as rapidly as possible
instead of heating slowly for 10 minutes. Note time required in each case to collect
the required amount of distillate.
All experiments should be made in triplicate and the results recorded in the enclosed
table. It is suggested that Pyrex glass apparatus be used throughout; if, however,
other glass is used, please note this fact; also include a measurement of the size of per-
foration in distilling shelf (3 inch hole is recommended) and the distance of the top of
the burner from the flask; also note whether or not at any time during the distillation
water was absent from the scrubbing bulb.
A. L. Prince and B. F. Robertson, for their own satisfaction, made
further experiments other than those included in the instructions sent
1 J. Ind. Eng. Chem., 1919, 11: 465
452 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
[Vol. V, No. 4
out, using the Hopkins distilling bulb in place of the Davisson scrubber.
They found that the results did not vary from the theoretical value
any more than those which were conducted with the Davisson scrubber.
These few results, however, are not included in the table since they are
insufficient to be conclusive.
Nitrogen in pure potassium nitrate.
ANALYST
A. L. Prince, Agricultural Experi-
ment Station, New Brunswick,
T. L. Roettger, Southern Cotton-
seed Oil Co., Savannah, Ga.....
W. D. Richardson, Swift & Co.,
Union Stock Yards, Chicago, IIl..
Ethel Schram, Armour & Co., Union
Stock Yards, Chicago, Il..
G. J. Kuhlmann, Jr., State Depart-
ment Agriculture, Harrisburg, Pa.
B. F. Robertson, Clemson Agri-
cultural College, Clemson Col-
lege sSNiG sya! ee tlaeiieeiee eeu
L. J. Jenkins and J. F. Ellis, Bureau
of Chemistry, Washington, D. C.
TABLE 1.
OF WEIGHT
TIME | POTAS- OF
SIUM | NITROGEN
NITRATE
minutes| gram gram
45 0.2 | 0.02766
60 0.2 | 0.02772
75 0.2 | 0.02779
45 0.5 | 0.06909
60 0.5 | 0.06939
75 0.5 | 0.06900
45 0.2 | 0.02803
60 0.2 | 0.02806
75 0.2 | 0.02807
45 0.5 | 0.06978
60 0.5 | 0.06975
75 0.5 | 0.06923
45 0.2 | 0.02754
60 0.2 | 0.02759
75 0.2 | 0.02759
45 0.5 | 0.06888
60 0.5 | 0.06908
75 0.5 | 0.06912
45 0.2 | 0.02775
60 0.2 | 0.02799
75 0.2 | 0.02784
45 0.5 | 0.06954
60 0.5 | 0.06951
75 0.5 | 0.06972
45 0.2 | 0.02710
60 0.2 | 0.02727
75 0.2 | 0.02727
45 0.5 | 0.06883
60 0.5 | 0.06843
75 0.5 | 0.06823
45 0.2 | 0.02490
60 0.2 pele
75 0.2 | 0.02723
45 0.5 | 0.05520
60 0.5 | 0.06425
75 0.5 | 0.06713
45 0.2 | 0.02774
60 0.2 | 0.02776
75 0.2 | 0.02786
45 0.5 | 0.06944
60 0.5 | 0.06942
75 0.5 | 0.06935
BLANK
gram
0.00014
0.00008
0.00014
0.00014
0.00008
0.00014
0.00030
0.00021
0.00028
0.00030
0.00021
0.00028
0.00023
0.00013
0.00011
0.00023
0.00013
0.00011
0.00017
0.00023
0.00032
0.00017
0.00023
0.00032
0.00060
0.00030
0.00025
0.00060
0.00030
0.00025
0.00020
0.00023
0.00030
0.00020
0.00023
0.00030
0.00021
0.00029
0.00031
0.00021
0.00029
0.00031
CORRECTED
WEIGHT OF! NITRO-
NITROGEN GEN
gram _|percent
0.02752 | 13.76
0.02764 | 13.82
0.02765 | 13.83
0.06895 | 13.79
0.06931 | 13.86
0.06886 | 13.77
0.02773 | 13.87
0.02785 | 13.93
0.02779 | 13.90
0.06948 | 13.90
0.06954 | 13.91
0.06895 | 13.79
0.02731 | 13.66
0.02746 | 13.73
0.02748 | 13.74
0.06865 | 13.73
0.06895 | 13.79
0.06901 | 13.80
0.02758 | 13.79
0.02776 | 13.88
0.02752 | 13.76
0.06937 | 13.87
0.06928 | 13.86
0.06940 | 13.88
0.02650 | 13.25
0.02697 | 13.49
0.02702 | 13.51
0.06823 | 13.65
0.06813 | 13.63
0.06798 | 13.60
0.02470 | 12.35
0.02650 | 13.25
0.02693 | 13.47
0.05500 | 11.00
0.06402 | 12.80
0.06683 | 13.37
0.02753 | 13.77
0.02747 | 13.74
0.02755 | 13.78
0.06923 | 13.85
0.06913 | 13.83
0.06904 | 13.81
a
eee
> +=
1922] PHELPS: REPORT ON NITROGEN 453
Comment by Robertson.—Some of the low nitrogen results were due to the scrubber
retarding the distillation if the time was less than 1 hour 30 minutes. The time given
in the directions was not enough. If the distillation was continued until 50 ce. or less
remained in the flask, the results very closely approached the theoretical. When
the Hopkins bulb was used better results were obtained in the specified time. From
work done with the scrubber, it was concluded (1) that it is not as accurate as the
Hopkins bulb; (2) that it is a hindrance to rapid work; (3) that the method has no ad-
vantage over the regular Kjeldahl method, and (4) that it is not as accurate for regular
routine work.
' The experiments in Table 2 were conducted in order to determine
whether or not any ammonia was lost by rapid reduction and distilla-
tion. Five out of seven of the reports indicate that no appreciable
amount of ammonia is lost through the rapid reduction and distillation
of the nitrate, while two reports show an appreciable loss. Here again
it is believed the number of reports are insufficient to determine whether
or not there is a loss of ammonia.
TABLE 2.
Loss of ammonia by rapid reduction and distillation.
WEIGHT OF NUMBER OF AVERAGE
ANALYST TIME POTASSIUM DETERMINA- WEIGHT OF
NITRATE TIONS NITROGEN
minutes gram gram
ACH METITIGE Eis ess sorte 31 0.5 2 0.06913
MEV Torbteer.. elsiisocy. seed. dae 35 0.5 5S 0.06440
Wis Do Richardson. «202.0 5.45 «.</s 34 0.5 5 0.06911
PLHCMSCOLAMIN S658 ats tacecie 52 0.5 5 0.06958
Gis Kuhlmann; Jr:; 2). 322% 28 0.5 5 0.06830
Ee PP PURODERESOM es. os oe ac cies e's « 75 0.5 6 0.06566
Bureau of Chemistry............ 33 0.5 6 0.06925
CONCLUSION.
It is not possible to derive any definite conclusion from the figures
representing the work of so few analysts. Six of the seven results re-
ported, however, especially those in which the reduction and distillation
were conducted for a period of one hour or more, agree sufficiently to
warrant further investigation of this method for the determination of
nitrate nitrogen. The number of sets in agreement indicate that the
method is reasonably free from source of error and gives fairly uniform
results in the hands of different analysts.
RECOMMENDATIONS.
It is recommended—
(1) That the association continue the study of the Devarda method.
(2) That a comparison of results be made with the suggested modified
Kjeldahl-Gunning method, by H. C. Moore', for the determination of
nitrate nitrogen in nitrates and fertilizers.
1J. Ind. Eng. Chem., 1920, 12: 669.
454 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
THE AVAILABILITY OF NITROGEN BY THE ALKALINE
PERMANGANATE METHOD.
By E. W. Macruper (F. 8S. Royster Guano Co., Norfolk, Va.).
During the past year the writer had occasion to study a number of
analyses of fertilizer materials and of mixed goods by the alkaline per-
manganate method and to check results with a number of other chem-
ists. Your attention is directed to some of the problems presented.
At the meeting of the American Chemical Society in September, C. S.
Robinson presented a paper on this subject, and his work shows that he
is going to the very root of the subject. His results do not seem to
uphold the official method! from a scientific standpoint, for where a
method designed to show the availability of organic compounds gives
urea an availability of not over 20 per cent, as is shown by his results,
it would seem that something is fundamentally wrong.
Our official method says to digest with permanganate for not less
than 30 minutes, gradually raise the temperature and, after danger of
frothing has passed, distil. This leaves a very wide latitude for digest-
ion. It was found with many samples that if 30 minutes only were
allowed for digestion, so much frothing occurred that the time of dis-
tillation was greatly increased. In a strong alkaline permanganate
solution, the time of digestion ought to make a considerable difference
in the amount of nitrogen given off, so that two people following the
official method would get varying results, depending upon the time
taken in the digestion. It is suggested that the directions be made
more specific.
TABLE 1.
Determination of water-insoluble nitrogen.
Sample CATHCART* ROYSTER FHASKINST CARPENTER JONESY
No. GUANO CO.
per cenit per cent per cent per cent per cent
1 0.49 0.64 53
2 0.22 0.37 th
3 0.57 0.67 ney:
4 1.06 1.22 Paalahs was
5 a 1.04 0.94 ae
6 0.27 0.35 BA 0.23 0.41
if 0.30 0.45 it 0.34 0.49
|
*C. 8. Cathcart, New Brunswick, N. J.
fH. D. Haskins, Amherst, Mass.
TF. B. Carpenter, Richmond, Va.
§C. H. Jones, Burlington, Vt.
As permanganate acts on organic matter which does not contain
nitrogen, much of it is used up on other than nitrogenous materials,
and as large samples of low-grade materials have to be used, the large
1 Assoc. Official Agr. Chemists, Methods, 1920, 11.
1922] |MAGRUDER: NITROGEN BY THE PERMANGANATE METHOD 455
amount of organic matter present may account for the low availability.
A determination of the water-insoluble nitrogen should result in con-
cordant results, but the experience of the writer has been that chemists
get as great differences on water-insoluble nitrogen as on the permanga-
nate available, as the following results show:
Some of these differences may not be considered great, but when the
small amount of nitrogen is taken into consideration, the percentage of
activity is changed materially. If the chemists can not agree on the
water insoluble, no matter how closely they agree on the permanganate
active, there will be a wide difference in the results on permanganate
inactive and the percentage of activity.
The variation of results due to the use of different makes of filter
paper is a point worth considering.
TABLE 2.
Differences in percentage of activity caused by small differences in water insoluble and
permanganate active.
PERMANGANATE
ANALYST WATER AVAILABILITY
INSOLUBLE ° :
Active Inactive
per cent per cent per cent per cent
MURUHCATUS Sth a eetee she ss isk 0.22 0.12 0.10 53.60
Royster Guano Co........... 0.31 0.14 0.17 45.10
IEERLSHESS eee he a pa AOE 0.62 0.27 0.35 43.55
Royster Guano Co........... 0.59 0.31 0.28 52.54
Warpenters. Hee ene fe, 0.23 0.15 0.08 64.30
(Cathcart, ser ttasys cise cteielsy< 0.27 0.13 0.14 48.10
IOH Bh wes hal See eee 0.41 0.17 0.24 42.00
Royster Guano Co........... 0.35 0.16 0.19 45.20
(CPCUTNIGR oA Se eee 0.34 0.16 0.18 47.10
Gathcantity bt sonc0s eu tet 0.30 0.19 0.11 63.30
IGRES. CSO ae nea eee 0.49 0.22 0.27 45.00
Royster Guano Co........... 0.45 0.22 0.23 47.30
The differences shown are well within experimental error, yet the
percentages of activity vary so widely that one analyst would condemn
and the other pass the same goods and both with wide margins.
The interpretation of results also needs study and modification. At
present the activity of the nitrogen in fertilizer materials is based on the
relation between the water insoluble and permanganate active; it leaves
entirely out of consideration the water-soluble nitrogen, the most valu-
able portion. It would be better to calculate the value of the nitrogen
by comparing the permanganate active plus the water soluble with the
total.
456 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 3.
Availability of nitrogen by the alkaline permanganate method.
: PERMANGA- | PERMANGA- ACTIVITY
TOTAL WATER WATER NATE NATE eon BASED ON
SAMPLE NITROGEN | SOLUBLE | INSOLUBLE | ayarLaBLE | INACTIVE TOTAL
NITROGEN
per cent per cent per cent per cent per cent per cent per cent
1 9.16 1.26 7.90 5.82 2.08 73.67 77.29
2 8.83 6.36 2.47 1.24 1.23 50.20 86.36
It should be noted that Sample No. 2 has the higher water-soluble and lower per-
manganate inactive nitrogen, which should indicate the better source of nitrogen, but
by the present method of interpretation it has much the lower percentage of activity,
which indicates a poorer source of nitrogen.
REPORT ON POTASH?
By J. T. Foy (Clemson Agricultural College, Clemson College, S. C.),
Associate Referee.
It is recommended—
(1) That the method by Moore and Caldwell? which calls for the use
of stronger alcohol in connection with the Lindo-Gladding method be
studied further. This was recommended at the last meeting but no
samples were sent out to collaborators.
(2) That as the centrifugal method for determining potash, by Elmer
Sherrill’, seems to be applicable when a rapid determination for fac-
tory control is necessary, it is worthy of consideration, and should be
given a trial by the association. However, this method can not com-
pare with the Lindo-Gladding method for official use.
THE DETERMINATION OF SMALL AMOUNTS OF POTASH BY
THE LINDO-GLADDING METHOD.
By Witu1am Hazen (Bureau of Soils, Washington, D. C.).
A few years ago an investigation was made by Ross, Merz and Wagner
of the Bureau of Soilst on the recovery of potash as a by-product in the
cement industry. Recently a corresponding survey was made of the
blast-furnace industry. In these investigations numerous samples of
various materials were analyzed for potash. All analyses were made
1 Presented by R. N. Brackett.
2 J. Ind. Eng. Chem., 1920 12: 1188.
3 [bid., 1921, 13: 227.
4U.S. Dept. Agr. Bull. 572: 1917.
1922] HAZEN: POTASH BY THE LINDO-GLADDING METHOD 457
in the usual way by fusion in J. L. Smith crucibles and subsequent
treatment by the official Lindo-Gladding method.
The potash content of most of the samples analyzed was found to be
quite low, often less than 0.1 per cent. It was felt, therefore, that
special accuracy was required in this work as any constant error in the
results, although actually small, might have a relatively large effect
on the final estimates. In order to secure the greatest accuracy all
samples were analyzed by two chemists. When their results differed by
as much as 0.1 per cent the sample was analyzed by a third chemist.
The claim made by some authorities that the use of 80 per cent
alcohol—as called for in the official method—gave low results was,
of course, well known, but at the time these investigations were under-
taken the consensus of opinion seemed to be that the error arising from
this source was negligible.
Recently attention was again directed to this question. Moore and
Caldwell? found that when used in determining potash in the presence of
sodium salts 80 per cent alcohol gave low results, but that alcohol of
this strength was entirely satisfactory in the absence of sodium salts.
To explain this discrepancy, the view was advanced that when sodium
salts are present they form a solution with the alcohol, and that it is
the alcoholic sodium solution, rather than the alcohol alone, which
exerts a solvent’ action on the chloroplatinate precipitate and causes
low results in the determinations. As this sodium solution is not
formed so readily in 95 per cent alcohol, Moore and Caldwell found
that by using 95 per cent alcohol in the initial washing, this solu-
bility error may be avoided. After the sodium salts have been removed
by means of the Lindo-Gladding (ammonium chloride) solution, 80
per cent alcohol may be used without danger of dissolving any of the
precipitate.
As soda is associated with potash in all the raw materials used in the
cement and blast-furnace industries it was felt that the claims of Moore
and Caldwell required further attention, owing to the bearing they
might have on the investigations on the recovery of potash in these
industries. -
Accordingly, standard chloride and sulfate solutions of potassium and
sodium were prepared from C. P. chemicals which had been further
purified by recrystallization. Mixtures of these solutions were then
taken in which the potash varied from about 1 to 50 milligrams. Two
sets of determinations were made, in one of which the potash was asso-
ciated with varying amounts of sodium sulfate and in the other with
sodium chloride. Each set was divided into two groups, the excess
platinic chloride being removed with 80 per cent alcohol in one group
1 Assoc. Official Agr. Chemists, Methods, 1920, 12.
2 J. Ind. Eng. Chem., 1920, 12: 1188.
458 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
and with 95 per cent in the other. The final washing, after the am-
monium chloride treatment, was made throughout with 80 per cent
alcohol. Both groups of determinations were run at the same time so as
to restrict the varying factors to the two mentioned, viz., the effect of
the sodium salts and the strength of the alcohol used in washing the
precipitate.
TABLE 1.
Determination of potash using different concentrations of alcohol in the initial washing.
AMOUNTS TAKEN POTASSIUM OXIDE FOUND
Potassium Oxide Sodium Oxide 80 % Alcohol—Ammonium/95 % Aleohol—Ammonium
(as Sulfate) (as Sulfate) Chloride—80 % Alcohol | Chloride—S0% Alcohol
gram gram gram gram
SOUP iat ||) cies 8 ee 0.00235 0.00233
0.0025 0.0170 0.00217 0.00237
0.0025 0.0170 0.00217 0.00231
O00 50 ee. dl) a ek eee 0.00463 0.00482
0.0050 0.0060 0.00465 0.00491
OiO500Mas Tey! |eeel Ee 0.04990 0.05050
0.0500 0.1760 0.04910 0.04950
0.0500 0.3500 0.04890 0.04960
potassium oxide sodium oxide
(as chloride) (as chloride)
O00500os silt ak cee oe 0.00474 0.00485
0.00500 0.0160 0.00456 0.00493
O0OL 25 iis Wares bende - carne 0.00105 0.00110
0.00125 0.0033 O.00098.- |4) sehen
0.00125 0.0055 0.00090 0.00121
0.03000 0.0200 0.02940 0.02980
0.04000 0.0500 0.03900 0.04010
The results given in Table 1, which represent in each case the average
of two to six closely agreeing determinations, show that for the quanti-
ties of potash used low results were obtained in all cases when the first
washing was made with 80 per cent alcohol. The actual error in these
determinations is not great, but the percentage error when working
with small amounts is quite appreciable. However, the sodium salts,
both sulfates and chlorides, even when present in relatively large amounts,
affected the determinations but slightly. In many cases the results
were just as low with the potash salts alone as when appreciable amounts
of sodium salts were added.
The values obtained in these determinations are, therefore, in agree-
ment with the observations made by Moore and Caldwell regarding low
results with 80 per cent alcohol but not with their explanation that this
is mainly due to sodium salts.
When the first washing was made with 95 per cent alcohol the results
were somewhat better, but even in this case they were slightly but con-
sistently low, a fact which could only be explained on the assumption
1922] HAZEN: POTASH BY THE LINDO-GLADDING METHOD 459
that the alcohol (80 per cent), which was used subsequent to the ammo-
nium chloride treatment, exerted a solvent action on the potash pre-
cipitate. To ascertain the correctness of this theory determinations
were made in which 95 per cent alcohol was used both before and after
the ammonium chloride treatment. The same samples were also
determined by the two treatments shown in Table 1. The results of
these determinations are given in Table 2.
TABLE 2.
Determination of potash using different concentrations of alcohol in both the initial and
final washings.
AMOUNTS TAKEN POTASSIUM OXIDE FOUND
Patieanm Onde i Sodium! Oxide 80% Alcohol—Am- | 95% Alcohol—Am- | 95% Alcohol—
coat] eetinis” | mage ileal | mugen ical Amma, Cis
gram gram gram | gram gram
0.00125 b Ba 0.00105 | 0.00109 0.00127
0.00125 0.0020 0.00103 0.00110 0.00124
0.00125 0.0030 0.00104 | 0.00108 0.00128
0.00500 erccee 0.00440 | 0.00482 0.00492
In Table 2 it is seen that the 95 per cent method gives results that
agree almost exactly with the theoretical amounts taken, while the
results obtained with the other two methods are appreciably lower, as
was to be expected from the results given in Table 1. The effect of the
sodium salts is again shown to be quite negligible, and the logical conclu-
sion seems to be that the error observed in using 80 per cent alcohol is mainly
due to the solubility of the potash precipitate in alcohol of that strength.
Some determinations made with 90 per cent alcohol showed that it
may be safely used, and that it has the advantage over the 95 per cent
solution in that fewer washings are required to free the precipitate from
ammonium chloride and other foreign matter. Thus, using 0.0050 gram
of potassium oxide (as K.SO,) and 0.0100 gram of sodium oxide (as
-
TABLE 3.
Determination of potash in tron ores.
POTASSIUM OXIDE
Sample No.
80% Alcohol—Ammonium 90% Alcohol—Ammonium
Chloride—80 % Alcohol Chloride—90 % Alcohol
per cent per cent
533 9.120 0.128
539 0.147 0.205
541 0.200 0.248
542 0.140 0.170
460 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Na2SO;), four determinations in which 90 per cent alcohol was used
both before and after the ammonium chloride treatment gave results
averaging 0.00505 gram of potassium oxide.
In Table 3 are given some comparative results obtained in the analy-
sis of samples of iron ore. These again show that 80 per cent alcohol
gives lower results than the 90 per cent solution. However, the differ-
ences in the two sets of determinations are not sufficiently great to have
any serious effect on the potash recovery investigations to which refer-
ence has been made.
SUMMARY.
In the determination of potash 90 per cent alcohol gives better results
than the 80 per cent solution, and when working with small amounts
of potash and high accuracy is desired it is advisable to use the stronger
alcohol, both before and after the ammonium chloride treatment. How-
ever, it takes a longer time to wash out ammonium chloride salts with
the 90 per cent solution. Furthermore, in ordinary fertilizer work the
samples generally contain relatively high amounts of potash, in which
case the percentage error arising from the use of 80 per cent alcohol
will not be very serious. Therefore, in ordinary work the best pro-
cedure would be to use 90 per cent alcohol in the initial and 80 per cent
in the final treatment.
No report on potash availability was made by the associate referee.
REPORT ON PRECIPITATED PHOSPHATES.
By H. D. Haskins (Agricultural Experiment Station, Amherst, Mass.),
Associate Referee.
Following the recommendation of the association in 1920, that the
method for the determination of available phosphoric acid in pre-
cipitated phosphate be studied further, the work was continued as
outlined:
(1) Comparison of results obtained by the use of 1- and 2-gram charges, according
to manipulation as outlined in the official methods for the determination of soluble
and insoluble phosphoric acid in fertilizers’.
(2) The effect of two successive treatments, each employing 100 cc. of neutral am-
monium citrate, on a 2-gram charge of the precipitated phosphate. (The properly
washed residue obtained after the first treatment of the precipitated phosphate with
the citrate solution is introduced into the Erlenmeyer flask together with the filter
paper and the whole treated with a second application of 100 cc. of neutral ammonium
citrate, previously heated to 65° C. Manipulation to be the same as for the first treat-
ment.)
1 Assoc. Official Agr. Chemists, Methods, 1920, 4.
1922] HASKINS: REPORT ON PRECIPITATED PHOSPHATES 461
TABLE 1.
Results obtained in a study of methods for the delermination of phosphoric acid in pre-
cipitated phosphate.
|
| WATER-SOLUBLE CITRATE-INSOLUBLE
PHOSPHORIC PHOSPHORIC
AciD* acip*
TOTAL
ooo PHOS-
ANALYST PHORIC
2-Gram aciD*
2-Gram 1-Gram 2-Gram 1-Gram Charge
Charge Charge Charge Charge | (2 extrac-
tions)
S. § S. No. 597
r cent r cent recent recent r cent recent
Percy O’Meara, Agricultural of 1 vf sp a
Experiment Station, E.
Lansing, Mich........... 1.31 1.81 10.93 4.94
L.S. Walker, Amherst, Mass.) 1.68 2.00 12.21 6.82
41.27
41.15
a
ow
© bo
Whatman No. 1.
F. B. Carpenter, Virginia-
Carolina Chemical Co.,
Richmond, Va... ......... 0.95 1.23 12.76 8.45 3.88 40.90
William Hazen, Bureau of
Soils, Washington, D. C...| 1.97 bans 4.50 Lie: 41.26
iL, SAW CIL Goose 1.63 2.09 12.17 6.69 cee
J.H. Parkins, Royster Guano
Cos, Norfolk, Va: 225. 2. 1.49 1.93 10.51 3.83 0.07+ 41.42
Whatman No. 2.
Percy O’Meara............ 1.36 1.86 9.40 4.38 1.10
Wey WV BIKER... eee eee Oe 1.58 2.11 11.60 6.99 2.28
Munktell’s Swedish No. 1-F.
epaGarpenter... sn: <.. =~: 0.94 1.30 12.87 8.37 3.43
William Hazen............ 1.90 eens 5.90 Sinbe as
LSS WAL 2) eee 1.65 2.17 12.11 6.89 Saas
UE PArkINSs., ... {2 > 6 << 1.59 1.91 10.52 3.83 0.077
|
Munktell’s Swedish No. 2.
Percy O’Meara............ Weiss 1.84 9.47 4.58 1.19
LL SPE 1.63 2.14 12.21 7.12
Durieuzr French No. 121.
F. B. Carpenter............ Ely 1.53 13.07 7.78 4.06
William Hazen............ 2.02 a 3.62 ae Pies
WePomWelker. 2-5: cnt sek 4 1.75 2.35 11.90 6.92 fee
ere Parkins.) 5...\ 5.004 90! 1.73 2.05 10.23 3.80 0.077
ely af 2 Beeman,
-gram charge used. : 9
Nore.—L. S. Walker, using the Wagner method (500 cc. of 2% citric acid to a charge) and S. & S. No.
597 filter paper, obtained the following results: 5-gram charge—30.23 %; 2l4-gram charge—
40.65 % of available phosphoric acid.
462 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
(3) To study the effect of a 2% citric acid solution on the precipitated phosphate.
Manipulation to be according to the tentative Wagner method! for the determination
of the citrate soluble phosphoric acid in basic slag.
(4) To study the adaptability of the various grades of paper for the filtration after
the digestion of the 2-gram charge of the precipitated phosphate. (Experience has
shown that the S. & S. No. 597 filter paper which was familiar to most chemists in pre-
war times was particularly adapted for this use. Many other papers have been found
too porous, allowing the very fine particles of precipitated phosphate to pass through.
The difficulty in securing S. & S. No. 597 filter paper of the same quality as formerly
seems to warrant the accumulation of experimental data with as large a variety of
papers as possible, with a view to selecting a satisfactory substitute).
Samples were prepared and sent to seven chemists. Five reported
the detailed results shown in Table 1.
The wide difference in the results of four of the chemists is due largely
to variation in neutrality and strength of the ammonium citrate used.
Therefore the results of all analysis should be studied separately before
drawing conclusions.
A comparison of the results for insoluble phosphoric acid, using 2-
and 1-gram charges, manipulation according to the official method
with neutral ammonium citrate as a solvent, is shown in Table 2.
TABLE 2.
Comparison of results for insoluble phosphoric acid.
INSOLUBLE PHOSPHORIC ACID 1-Gram
Charge (Per-
centage De-
hee 2-Gram 1-Gram Chae aslable
Charge Charge (2 extractions) Phosphoric
Acid)
per cent per cent per cent
Lisoe Walken igia-c eben ot 12.03* 6.91* 2.01* 42.5
Percy/O'Mearats . s2-0 oe ak 9.93 4.63 1.20 53.0
He Garpenters nts eo ee 12.90 8.20 3.79 36.0
William Hazen............. 4.67 ee vies wry
J. H. Parkins... . ‘ RE oC 10.42 3.82 0.07 f 63.3
* Average of 12 tests; all other figures show averages of 6 tests.
+ l-gram charge used.
The results given in Table 2 show that a much lower percentage of
insoluble phosphoric acid is obtained by using a 1-gram than a 2-gram
charge, manipulation according to the official method, the percentage
decrease varying from 36.0 to 63.3. A 2-gram charge subjected to 2
successive extractions of 100 ce. each of neutral ammonium citrate
gives even lower percentages of insoluble phosphoric acid, but the writer
is of the opinion that the extra manipulation which the modified method
entails would hardly warrant serious consideration of its adoption by
“1 Assoc. Official Agr. Chemists, Methods, 1920, 14.
1922] HASKINS: REPORT ON PRECIPITATED PHOSPHATES 463
the association. The results, however, emphasize the inadequacy of
the present official method for the treatment of this class of materials.
Nore.—Since this report was presented the writer, acting upon
suggestions of Committee A, has had this phase of the work amplified.
One gram of the phosphate subjected to 2 successive treatments of
100 cc. each of neutral ammonium citrate gave 0.06% of insoluble
phosphoric acid as an average of 3 determinations. A similar test
made in the laboratory of the Royster Guano Company gave 0.07% as
an average of 6 tests (Table 2). The use of a 14-gram charge with 2
successive treatments of 100 cc. each of neutral citrate solution gave
but a mere trace of insoluble phosphoric acid.
Results which form a part of Table 1 were secured at the Massa-
chusetts Agricultural Experiment Station by the treatment of 5- and
214-gram charges with 500 cc. of a 2 per cent solution of citric acid,
according to the tentative Wagner method. The results obtained with
a 5-gram charge on available phosphoric acid correspond with those
secured by the official method employing a 2-gram charge with neutral
ammonium citrate. The Wagner method with a 214-gram charge shows
practically all of the phosphoric acid in available form. It is con-
sidered that this method (introduced for the treatment of basic phos-
phate products which have a tendency to decompose the neutral ammo-
nium citrate solution) is not applicable for the treatment of precipitated
phosphate which is neutral or slightly acid in reaction.
The results of a study by Walker of Anaconda treble superphosphate
as to the effect on the available phosphoric acid by using a 1-gram
charge, with manipulation according to the official method, are shown
as follows, expressed in percentage:
NVIOISCUILE ee re mec ene tate atte EP ette Braelatcrajsr ee: « 3.11
Motaliphosphorie acide: 152 Bele eM. Jd: eileesinesiess tesa 47.82
Water-soluble phosphoric acid
1 41.59
2 a | washed with 250 cc. of waters’. SUE fo tes! 41.46
Insoluble phosphoric acid
Tigram Vereatea with 100 cc. of neutral citrate............ f 2.22
2 grams { . \ 2.26
Attention is called to the fact that with materials of this class, the
employment of a 1-gram charge apparently does not give any lower
insoluble phosphoric acid than does the use of 2 grams. This would
bear out the theory that the high insoluble phosphoric acid tests on
precipitated phosphate which follow the use of a 2-gram charge with
neutral ammonium citrate are due largely to the over-saturation of the
citrate solution with phosphate of lime.
Results secured by the various collaborators would indicate that any
one of the six filter papers tested was fairly well adapted to the work,
464 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
although it was observed that the Durieux No. 121 was considerably
slower than the others, and if many tests were to be made it might be
advisable to use one of the Whatman papers, preferably No. 2, or the
S. & S. No. 597.
SUMMARY.
The conclusions to be drawn from these studies coincide with the con-
clusions of the preceding year. Both emphasize the inadequacy of the
present official method for the analysis of the precipitated phosphates.
It may be pointed out—
(1) That satisfactory results are obtained in the determination of
available phosphoric acid by the present official method on fertilizer
mixtures in which precipitated phosphate has been used as a source of
available phosphoric acid.
(2) That precipitated phosphate receives the preference of the average
Connecticut Valley tobacco grower, both as a source of phosphoric acid
in fertilizer mixtures and where the purchase of chemicals and crude
stock materials is the custom.
(3) That results of vegetation tests described in the report on pre-
cipitated phosphate for 1920 show this product to be a good source of
available phosphoric acid.
Your associate referee is of the opinion that further work on the sub-
ject is not warranted.
RECOMMENDATIONS.
It is recommended—
(1) That the determination of insoluble phosphoric acid in precipi-
tated phosphates be carried out according to the present official method
for the determination of insoluble phosphoric acid in fertilizers!, with
the exception that a 1-gram charge be employed.
(2) That a perforated platinum crucible and gentle suction be em-
ployed in the filtration of the citrate solution after treatment, and that
a filter paper be employed that will insure a free and rapid filtration
without allowing the finely divided particles to pass through. The
following papers have been found satisfactory (and there may be others) :
S. & S. No. 597, Whatman No. 2, Whatman No. 1, Munktell’s No. 1-F,
Munktell’s No. 2 and Durieux No. 121.
W. H. Ross, C. B. Durgin and R. M. Jones (Bureau of Soils, Wash-
ington, D. C.), presented a paper on ‘“The Composition of Commercial
Tee Acid’?
1 Assoc. Official Agr. Chemists, ees 1920, 4.
2J. Ind. Eng. Chem., 1922, 14
1922] WILEY: PHOSPHORUS BY THE OFFICIAL METHOD 465
THE DETERMINATION OF EXTREMELY SMALL AMOUNTS
OF PHOSPHORUS BY THE OFFICIAL METHOD'.
By R. C. Witey (University of Maryland, College Park, Md.).
In the course of research work last winter, the writer had occasion to
determine phosphorus with extreme accuracy. The following applica-
tion of the official volumetric method? was formulated. No originality
is claimed, but the scheme is given with the hope that it will prove
useful to others who are doing similar work.
Bowser®, Raper‘, Serger’ and Veitch® are prominent among the chem-
ists who have worked upon the determination of small amounts of
phosphorus. Al! used the molybdate method or some modification of it.
The method used by the writer is as follows:
Measure an aliquot of the solution into a beaker and add 20 cc. of a saturated solu-
tion of ammonium nitrate and enough water to make the total volume about 75 ce.
Heat the solution to 55°C. in a water bath and add ammonium molybdate solution of
the same temperature. After 15 minutes filter off the precipitate and carefully wash
free from acid with distilled water. (It has been found that it is quite possible to have
the washings free from acid and yet have acid on the top of the filter paper, especially
under the folds, and it is always well to test these localities carefully before pronouncing
the precipitate free from acid.) Carefully transfer the precipitate and paper into the
beaker and dissolve in 0.2N sodium hydroxide. Add phenolphthalein. Neutralize
the solution with 0.1N sulfuric acid and from the difference in readings calculate the
amount of phosphorus.
One of the most essential points in the determination is to refrain
from pulping or unduly tearing the filter paper in dissolving the pre-
cipitate or in subsequent titration with the standard acid. If this
precaution is not taken the color of the indicator is occluded to such an
extent by the filter paper fibers that the end point can not be distinctly
seen, whereas if the filter paper fiber is not pulped the exact point of
the change from alkalinity to acidity can be seen. That such brilliancy
as the alkaline color of phenolphthalein should be masked by the oc-
clusion of white filter paper fiber may seem strange, but such is the
case. ‘
As 1 ce. of 0.1N solution is equivalent to 0.00013 gram of phosphorus,
and the error in reading is not more than 0.1 to 0.05 cc., it follows that
a difference as little as 0.01 milligram of phosphorus can be detected.
The following results show how pulping the filter paper fiber causes
variation in results:
1 Presented by R. B. Deemer.
2 Assoc. Official Agr. Ghee: Methods, 1920, 3.
3 Am. Chem. J., 1911, 45: 230.
* Biochem. J., 1914, 8: pay
5 Chem. Zig., 1915, 39:
U.S. Bur. Chem. Pull "30: (1905), 188
466 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Phosphorus.
SOLUTION PAPER PULPED VARIATION PAPER NOT PULPED VARIATION
mgs. mg mgs. mg.
19.42 19.24 0.02
19.39 19.26
1 19.45
19.20 0.25
6.46 6.32 0.00
2 6.21 6.32
6.31
6.42 0.25
apilr¢ 3.27
3 3.25 3.28 0.01
3.24
3.38 0.21
3.31 3.26 0.01
4 3.25 3.27
3.44
3.35 0.19
The tabluated results show clearly the disadvantage of pulping the
filter paper in the determination.
The following results, expressed as milligrams, were obtained in
determining the amount of phosphorus in the washings from silica gel:
SAMPLE NO. 1. | SAMPLE No. 2.
Ustswashinipiers,..ccrstcnrs eae 4.15 4.74
11th washing.............: 0.10 0.14
PS WASDING 5 6 oso osu ahcaryas 0.06 0.12
SUSESWASHING -i.7.t- cokes 0.06 0.12
4istiwashing .072t5,.8% Jeet 0.05 0.10
The foregoing results, the writer believes, show that the official method
can be used in this way for the rapid determination of very small amounts
of phosphorus.
1922] PATTEN: REPORT ON INORGANIC PLANT CONSTITUENTS 467
REPORT ON INORGANIC PLANT CONSTITUENTS
(Calcium, magnesium, iron and aluminium in the ash of seed).
By A. J. Patten (Michigan Experiment Station, E. Lansing, Mich.),
Referee.
The work carried on during the past year followed the recommenda-
tions made by the association at its last meeting.
For the determination of calcium, magnesium and manganese in the
ash of seeds the methods! that have been before the association since
1916 gave satisfactory results. A method for the determination of
iron and aluminium in the filtrate from the magnesium determination
was also studied in the referee’s laboratory. For this work a hydro-
chloric acid solution representing the approximate composition of the
ash of seeds was prepared with the following ingredients, expressed as
grams per 1000 cc.:
Phosphorus pentoxide (P:0;).................... 4.500
Galemmmiboxider(GaO) a5. o eee e ee co aes 0.500
IMapnesiumioxides(MeO)i....... 025.5 a2 sce 0.800
Manganomanganic oxide (Mn;0,)................ 0.020
Aluminumijoxide;(Al,03)\.2%- « «2 sees 8 ee Se? 0.112
Hericwxide: (HesOs) isan aaee sane en)- fe brea s 0.168
Potassium oxide (Ki;O)).....:..-2.--. «heise a bat 2.500
Sodrumioxides(NasO)ia a5 ys iees 2) eels seceh: 1.400
MOtale ye eters ends oe cd bere eR ga ee. Haaser 10.000
Results of collaborative tests are shown in the following table:
Results on synthetic solution.
CALCIUM MAGNESIUM MANGANO-
ANALYST OXIDE OXIDE MANGANIC
OXIDE
per cent per cent per cent
I. H. Hopper, Agricultural College, N. Dakota.... 4.85 8.40 0.22
O. B. Winter, Agricultural Experiment Station, E.
earistr apy VUE ce oy orate ahsrs catsvape ye ape Spc\ spends 4.96 8.22 0.21
M. L. Grettenberger, Agricultural Experiment Sta- .
Hon, Er. Bansmp,) Michio. 42.):. basi). fest sts - © 5.02 8.56 0.20
in. dh ILACIG So RUga dee Be OR RIDE ee aE pene Coe 4.86 8.22 0.22
Averdges: [nsf meet rio (ewas eewttre als 4.92 8.35 0.21
Sieech Qe ea eee 5.00 | 8.00 | 0.20
Difference)... 2... dhesRee heheh Jee 9 ee 008% si |i» 0:35 0.01
The results for calcium and manganese are very good indeed, but
those for magnesium are invariably high due, probably, to occlusion
of small amounts of iron or aluminium phosphate.
1J. Assoc. Official Agr. Chemists, 1921, 4: 392.
468 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
IRON AND ALUMINIUM.
For the determination of iron and aluminium in the ash of seeds it
is necessary to precipitate them as phosphates, since it is altogether
impracticable to remove the large amount of phosphoric acid. It is
also necessary to remove the sodium citrate before the iron and alumin-
ium can be precipitated. Evaporation with nitric acid alone or nitric
and sulfuric acid did not prove entirely satisfactory in removing the
sodium citrate, so the following procedure was tried:
The filtrate from the magnesium determination was evaporated to dryness after the
addition of 15 ce. of nitric acid. Sulfuric acid and 1 cc. of perchloric acid were added
and the solution again evaporated to dryness. The residue was taken up with hot
water and hydrochloric acid, boiled, filtered, and the iron and aluminium precipitated
by the addition of ammonium hydroxide and ammonium acetate.
The results obtained are encouraging and warrant further work.
RECOMMENDATIONS.
It is recommended—
(1) That further work be done on the determination of calcium and
magnesium in the ash of seeds.
(2) That the method for manganese as given in the body of this
report be adopted as official.
(3) That further study be given to the determination of iron and
aluminium in the ash of seeds.
REPORT ON SULFUR AND PHOSPHORUS IN THE SEEDS OF
PLANTS.
By W. L. LarsHaw (Agricultural Experiment Station, Manhattan,
Kans.), Associate Referee.
During the past year work was attempted in accordance with the
suggestions and recommendations adopted at the meeting of the asso-
ciation in 1920'. As a definite method had not been outlined, it was
considered inadvisable to submit samples to other collaborators.
Three samples of seed products were used: Soy bean meal, cottonseed
meal and mustard seed meal. As the mustard seed meal was extremely
oily it was mixed with 50 per cent of potato starch.
Various amounts of the sample, from 0.2 of a gram to 1.0 gram, were
tried; also from 0.2 to 0.8 gram of potassium chlorate, and from 10 to
18 grams of sodium peroxide. The larger amounts proving the more
reliable, they were incorporated into the following procedure:
1 J. Assoc. Official Agr. Chemists, 1921, 5: 136.
1922] LATSHAW: SULFUR AND PHOSPHORUS IN THE SEEDS OF PLANTS 469
ORGANIC AND INORGANIC SULFUR AND PHOSPHORUS
IN THE SEEDS OF PLANTS
APPARATUS.
Parr peroxide bomb.—For sulfur determination to be made independent of colorific
orocess.
REAGENTS.
(a) Sodium peroride (free from sulfur and phosphorus).
(b) Potassium chlorate, finely ground.
OXIDATION AND SOLUTION.
Weigh into the bomb a i-gram sample of the seed under examination, ground to
pass a 4-mm. sieve. Add in the order mentioned 0.7 gram of potassium chlorate and
15-17 grams of sodium peroxide. Seal the bomb and shake the charge thoroughly.
Bring the base of the bomb into contact with a small but very hot flame from the blast
lamp. (A sudden intensifying of the glow on the wall of the bomb indicates that the
charge has been exploded.) After allowing the bomb to cool, transfer the contents to
a beaker with the aid of a funnel and a stream of hot water; acidify 2% with hydro-
chloric acid. Filter off any unoxidized particles of carbon, and the filtrate is ready for
the determination of sulfur.
SULFUR.
Proceed as directed for sulfuric acid!.
PHOSPHORUS.
Evaporate the filtrate from the sulfur determination to a uniform volume, taking
aliquot portions when the phosphorus expected is high, and proceed as directed by the
official method?.
The results on the various samples of cottonseed meal, soy bean
meal and mustard seed meal by the foregoing procedure are as follows,
expressed in percentage:
SULFUR PHOSPHORUS
0.53 2.02
0.52 1.98
0.56 2.12
Cottonseed meal............2....55 0.49 2.14
0.49 2.20
0.52 2.14
0.51 PEWS
0.42 1.26
0.43 3 1.28
Savabean meal hci ity ci Sere vs, deen 0.43 122
0.39 1.22
0.35 1.21
0.41 Lol
1.17 1.54
1.16 1.60
1.14 57
Mustard seed meal ............... 1.08 1.59
1.10 1.59
1.06 1.60
1.10 1.58
1 Assoc. Official Agr. Chemists, Methods, 1920, 18.
*Thid., 3.
470 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
A small amount of carbon remained after the charge was neutralized
and made acid. The carbon residues from 18 determinations averaged
0.51 per cent of the sample taken. This small amount was considered
negligible so far as the phosphorus and sulfur were concerned.
Acting upon the suggestion of the referee, A. J. Patten, another
method! was tried. Twelve determinations on the several meals were
started at the same time, using the utmost care. Shortly after the
heat was applied to the crucibles one of them exploded with violence,
and before the analyst could turn the gas out ten more had exploded,
all with considerable violence. The writer had used this method pre-
viously with some success in making determinations for sulfur in plant
material and had hoped to get some figures for comparison. A lack of
time prevented the making of additional trials.
It is recommended that the method as outlined be studied by the
incoming referee and various other collaborators, in order that the
results of their findings may determine the advisability of its adoption
as an official procedure.
No general report on dairy products was made by the referee.
THE CRYOSCOPIC EXAMINATION OF MILK.
By Juxius Hortvetr (State Dairy and Food Commission, St. Paul,
Minn.), Referee.
The work of the referee during the past year was a continuation of
the investigation conducted during the year 1920 and was in compliance
with the recommendation adopted at the meeting held in November
last. The plan of the work covered by the present report includes some
features which have not heretofore been given special consideration—
notably, the standardization of thermometers and the investigation of
milk samples obtained from individual cows and herds known to be
under pathologic disturbance, under unusual physical strain, or under
abnormal conditions as to housing or feeding. Also it was deemed
advisable to continue the systematic investigation of a number of series
of samples mixed with known proportions of water in order to exhibit
as fully as possible the true value of the cryoscopic method when ap-
plied alone or in conjunction with other methods which have been
adopted as official or for some time have been regarded as standard.
There was also borne in mind the necessity of giving due consideration
to experimental errors, correction factors and tolerances justified under
practical conditions. The general plan of the work outlined early in
the present year is embodied in the following instructions issued to the
collaborators:
1J. Assoc. Official Agr. Chemists, 1915, 1: 56.
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 471
OUTLINE OF COLLABORATIVE WORK.
I. Standardization of thermometer:
(a) Location of freezing-point of pure water (true 0 of scale).
(b) Location of freezing-point of solution of 10 grams pure sucrose in pure water
made up to 100 cc. at 20°C.
(c) Location of freezing-point of solution of 7 grams pure sucrose in pure water made
up to 100 ce. at 20°C.
II. Known-pure milk, including 3 samples from individual cows and 3 samples from
herds:
(a) Mix each milk with water in exact proportions, as follows: 5, 7, 9, 11, 13, 15 per
cent by volume.
(b) Make determinations of specific gravity (at 60°F.), fat and solids-not-fat (calcu-
lated) on each milk sample and mixtures prepared therefrom.
(c) Determine lactose on each whole milk sample.
(d) Make freezing-point determinations! on each milk sample and on each mixture
prepared therefrom.
(e) Make immersion refractometer readings (at 20°C.) on acetic serum and copper
serum prepared from each milk sample and on each mixture prepared therefrom.
(f) Make ash determination on each acetic serum prepared in (e).
III. Known-genuine milk, including:
(a) Milk from individual cows of different breeds;
(b) Mixed milk of herds.
Make determinations of specific gravity, fat, solids-not-fat and freezing-point! on all
samples.
1NotE.—Make freezing-point determinations only on samples which are fairly
sweet or fresh, i. e., samples which show an acidity test of not more than 0.01% or
0.02% above 0.15% (expressed in terms of lactic acid). Make the acidity determina-
tion according to the following method:
Measure out 17.6 cc. of sample using the 17.6 cc. Babcock pipet; dilute with an
equal volume of water (free from carbon dioxide), washing out the pipet with the
same; add 0.5 c>. of phenolphthalein indicator, and titrate with 0.1N sodium hydroxide.
The number of cc. of 0.1N sodium hydroxide required to neutralize the sample of milk
divided by 20 gives the percentage of lactic acid.
As a preparation for collaborative work on the cryoscopic examination of milk, it
will be necessary to carry out a series of tests on the special thermometer to be used
in the freezing-point determinations by means of the following: (1) A sample of recently
boiled distilled water; (2) a solution consisting of 10 grams of pure sucrose dissolved in
pure water made up to a volume of exactly 100 cc. at 20°C.; and (3) a solution consist-
ing of 7 grams of pure sucrose dissolved in pure water made up to a volume of exactly
100 ce. at 20°C. :
Each of the above determinations is to be repeated not less than 3 times.
As a preparation for the above determinations it is necessary that the collaborators
devote a sufficient amount of time to preliminary trials for the purpose of becoming
thoroughly familiar with the construction of the cryoscope and its method of opera-
tion. A description of the standard method of procedure is enclosed herewith.
A sample of pure sucrose can be obtained by application to the Director of the Bureau
of Standards, Department of Commerce and Labor, Washington, D. C., The sucrose
samples should be ordered promptly in order that there may be ample time for carry-
ing out the outlined determinations.
There is also enclosed herewith a blank form on which the results of the freezing-
point determinations are to be tabulated. Collaborators are required to report results
to the referee, if possible, before February 15th. As soon as results have been obtained
472 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
and the thermometer corrections worked out in comparison with a Bureau of Stand-
ards tested instrument, the general outline for collaborative work on samples of milk
will be sent out. It is hoped that this first step which relates entirely to the testing
and standardizing of thermometers will be attended to as promptly and carefully as
possible.
]
SOLUTION OF 10 GRAMS PURE SOLUTION OF 7 GRAMS PURE
Recently SUCROSE IN PURE WATER TO | SUCROSE IN PURE WATER TO
Boiled 100 ce. ar 20°C. | 100 ce. at 20°C.
Determina- Distilled Sa
tions Water ae = . oe c :
SS Position of Freezing Point Position of Freezing Point
5 Observed Depression S-W Observed Depression S-W
Freezing-point (-S)}|_ (Algebraic) | Freezing-point (-S) (Algebraic)
Ist
|
mM el
2nd |
|
3rd
Averages XXXXXXXX | XXXXXXXX
—_——————_—————_Collaborator.
Express the results on the sucrose solutions as degrees freezing-point depression
below the average of the observed freezing point obtained on the sample of pure water
(+W), which may be above (+) or below (—) the 0-mark on the scale. In other
words, each freezing-point depression of the sucrose solution will be obtained by the
algebraic subtraction of the average of the freezing-point readings of pure water from
each observed freezing-point of the sucrose solution. No corrections are to be applied
in obtaining the freezing-point depressions, excepting as above stated, owing to the
fact that all determinations are to be carefully carried out under the same conditions.
Prepare the sucrose solutions by dissolving, accurately weighed out, 10 grams and
7 grams respectively of pure sucrose in pure water, and make the solution up to a volume
of exactly 100 cc. at 20°C.
Nore.—Do not include in your report any adventitious results, i. e., results which
are in marked disagreement with other results obtained by carefully following instrue-
tions. If any results appear to be erratic, they should be investigated and the tests
carefully repeated.
Herewith I am sending you outline of instructions for A. O. A. C. collaborative work
on the cryoscopy of milk. You have already received detailed instructions regarding
Section I.—Standardization of Thermometer. It is desired that results which you have
obtained on your thermometer be reported to the referee at an early date. The freezing-
point readings on your thermometer are to be compared with readings obtained on a
U. S. Bureau of Standards tested thermometer as given in the tabulation herewith
enclosed. By comparing results on these two thermometers you will readily determine
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 473
whether your thermometer is sufficiently correct or whether it will be necessary to
multiply by a correction factor in order to obtain correct results.
The remainder of the collaborative work you will find outlined in Sections II and III.
Collaborators are requested as far as possible to complete all of the work included in
the outlines. But, whenever it appears to be impossible to handle all the work, a
choice may be made between Sections II and III. It is especially desirable that all
collaborators carry out the plan of work outlined in Section III and as far as possible
to undertake the work outlined for the samples described in Section IT.
Samples of known-pure milk suitable for the collaborative work are to be obtained
under careful supervision, i. e., in such a manner that there can be no question regard-
ing their genuineness. It is not desired to give any attention to samples which are
obtained from cows or herds which are known to be poorly fed or kept under such
conditions that are not likely to yield wholesome marketable milk. In obtaining
samples to be used for the purposes outlined in Section II it is directed that milk repre-
senting various breeds of cows be included. For example, milk from individual cows
may represent various breeds such as Holstein, Jersey, Guernsey, Ayrshire, etc. The
samples should represent as many different breeds of cattle as can conveniently be
found in your locality, with the important requirement, as indicated above, that in all
cases samples are known to be authentic and from properly fed healthy animals.
The analytical determinations are to be made in accordance with methods described
in Official and Tentative A. O. A. C. Methods of Analysis, Revised to November 1,
1919. The lactose determinations are to be made by the gravimetric method—official,
given in XXJI, 11. The refractometric examinations are to be made according to
methods described in X XI, 16-18, and the ash determinations are to be made accord-
ing to method described in 16 (b). The freezing-point determinations are to be made
according to the method described in the Journal of Industrial and Engineering Chem-
istry, March, 1921, pages 198-208. Determine specific gravity by means of an accu-
rately graduated lactometer or hydrometer, or better by means of a Westphal balance,
at 60°F. Make fat determinations by means of the Babcock method as described in
Methods of Analysis, X XI, 13, 14, 15, and express results to 0.1 per cent. Calcu-
late solids-not-fat from results obtained by the specific gravity and fat determinations.
Repeat all doubtful determinations and do not include any results which appear to
be erratic or questionable. It is desired that all results be checked very carefully and
any results which appear to be unusual or questionable are to be investigated and
verified.
Tabulate results obtained in Section II according to the form of tabulation shown in
the article, “The Cryoscopy of Milk”, Journal of Industrial and Engineering Chem-
istry, March 1921, pages 192-208.
MISCELLANEOUS INSTRUCTIONS.
-
I. Thermometer:
(a) Examine the thermometer very carefully, using a lens if necessary, in order to
determine whether any defects exist in the glass or in the mercury thread. Dislodge
any particle of mercury which may be adhering to the inner surface of the space at the
top of the stem. Also dislodge any gas bubble which may be noticeable in the bulb
or which may form a separation at any part of the mercury thread. When the ther-
mometer is brought into proper condition for use:
(b) Make standardization tests according to directions outlined under Section I
of general instructions for collaborative work.
(c) Keep the thermometer always in upright position. In removing from stopper
or reinserting in position do not turn the thermometer to an inverted position and
avoid a horizontal position as much as possible. When the thermometer has once
474 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
been properly adjusted and carefully tested out it should be handled at all times with
great care.
(d) Test out the thermometer at frequent intervals, once a week or more often, in
order to keep an accurate record of any changes which may occur. Determine the
true 0-position and the depression produced by a standard sucrose solution often enough
to be certain at all times regarding the reliability of results.
II. The cryoscope:
(a) For a description of the cryoscope and its method of construction consult the
Journal of Industrial and Engineering Chemistry, March 1921, pages 198-208.
(b) The apparatus should be set up as carefully and perfectly as possible. All con-
nections should be sufficiently tight to avoid escape of ether vapors. Care should be
taken to avoid breakage of the Dewar flask. The perforated loop at the lower end of
the metal inlet tube should be adjusted to a position about 3 cm. above the bottom of
the flask. The rubber tube connecting the air-drying tube with the air-inlet tube
should be extended so as to cover the metal tube as far as the top surface of the cork.
When removing the upper section of the cryoscope simply withdraw the glass tube
which is inserted in the cork stopper at the top of the air-drying device.
(c) The bulb of the control thermometer should extend to a position about two-
thirds of the distance between the surface of the 400 cc. ether level and the bottom.
When the thermometer bas once been properly inserted in the cork it should remain in
position unless for special reason it may be necessary to withdraw it.
(d) Prepare a glass ether level gage of suitable length for inserting to within a short
distance above the bottom of the flask. Insert over the upper end of the gage tube a
short section of rubber tubing for the purpose of preventing breakage of the vacuum
flask when the tube is inserted into the ether. The lower end of the tube should be
provided with file marks indicating various ether levels, viz., 200 ec., 300 cc., 400 ce.,
etc.
(e) Place a small plug of cotton in the funnel tube (preferably a narrow short-stemmed
thistle tube) for the purpose of separating impurities which may be present in the ether
when being poured into the cryoscope.
(f) Pour into the air-drying tube only sufficient concentrated sulfuric acid to just
cover the perforations in the small bulb near the bottom of the tube. Do not allow
the sulfuric acid to rise to a level near the perforations at the shoulder of the mantle.
(g) The stirrer and freezing starter should both move freely in the metal tubes pro-
vided for them in the rubber stopper which holds the standard thermometer.
(h) Adjust the flow of water through the pump and regulate the pressure valve in
such a manner that air will be forced through the apparatus at a fairly rapid rate,
avoiding splashing or excessive foaming of the sulfuric acid. When all adjustments
are properly made and a free passage of air is maintained through the apparatus it is
possible to lower the temperature of the ether bath from approximately +20°C. to
0°C. in from 5 to 8 minutes. When the cooling action appears to be retarded the
sulfuric acid must be removed from the drying tube and a fresh supply poured in.
(i) The ether drain tube on the other side of the cryoscope should carry off the vapors
into the sink. No marked odor of ether should be noticeable at the top portion of the
drain tube. If ether yapors are not drawn out perfectly, increase somewhat the length
of the glass outlet tube which dips into the top of the drain. When the cryoscope is
not in use place a plug of cotton in the top of the drain tube in order to check a ten-
dency to vaporize. Remove the plug when the apparatus is in use.
(j) The glass tube at the back portion of the cryoscope stand is intended for holding
the standard thermometer when it is removed from the freezing test tube. Place a
pad of cork or rubber at the bottom of the tube to serve as a rest for the thermometer
bulb.
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 475
The procedure followed in making the freezing-point determinations!
has not been subjected to any material changes.
Replies were received from directors or chiefs in charge of eight labora-
tories signifying their willingness to assist in the collaborative work.
But owing to difficulties arising from insufficient laboratory help, in-
ability to provide necessary equipment, or pressure of official duties, a
number of laboratories were unable to report results under any of the
headings included in the outline of instructions. The referee was ex-
ceedingly fortunate in securing the assistance of the Milk Products
Department of Libby, McNeill & Libby, Chicago, IIl.,and of the chemists
employed at the company laboratory located at Morrison, Ill. Also of
great value as a contribution to these investigations was the cooperation
of the Associate Referee on the Cryoscopy of Milk and his assistants at
the State Agricultural Experiment Station, New Haven, Conn. A con-
siderable amount of work was also contributed by the chemists employed
in the laboratory of the Minnesota State Dairy and Food Department,
St. Paul, Minn. The individuals who rendered valuable assistance
during the past year and those who have been engaged in the collaborative
work are the following:
Libby, McNeill g Libby: G. A. Menge, H. L. Germann, R. T. Beard-
sley and R. H. Tucker.
Connecticut Agricultural Experiment Station: E. M. Bailey, R. E.
Andrew and R. T. Merwin.
Minnesota Dairy and Food Department: Henry Hoffman, Jr., Otto
Kueffner and C. S. Corl.
Of first importance in any cryoscopic work is the careful standardiza-
tion or testing of the thermometer. Not only is it necessary that the
standard freezing-test thermometer be given careful attention and
proper handling, but it is also of obvious consequence that the ther-
mometer whereby the temperature of the cooling bath is controlled be
also tested in order to insure its approximate accuracy. No cryoscopic
tests of any kind should be attempted on a thermometer whose scale
has not previously been calibrated and the necessary correction factors
determined. Collaborators were therefore directed; as a preparatory
procedure, to subject their thermometers to standardization tests after
the manner outlined in the foregoing instructions.
The results of the thermometer tests are included in Table 1.
The freezing-point depressions obtained by means of standard sucrose
solutions were applied for the purpose of correcting thermometer read-
ings in the manner illustrated in Fig. 1 and in the accompanying tables.
The illustrations are taken from two thermometers which yielded
J. Assoc. Official Agr. Chemists, 1921, 5: 174.
476 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
[Vol. V, No. 4
extreme variations from the normal, but they are nevertheless all the
more serviceable for the present purpose.
TABLE 1.
Results of thermometer tests.
7-GRAMS 10-GRAMS
THERMOMETER WATER SUCROSE TO SUCROSE TO INTERVAL CORRECTION
100 cc. 100 ce. rae
SG: LY °C. °C.
Standard...... +0.079 — 0.422 —0.621 031992; alincevetver tend
INOS GSD aE meee +0.030 —0.428 —0.626 0.198 x1.005
INOW teen Monee +0.056 —0.425 —0.621 0.196 x1.015
No. 24M...... +0.000 —0.422 —0.624 0.202 x0.985
NOSES eae +0.011 — 0.430 —0.630 0.200 x0.995
Gonne tices: +0.022 —0.422 — 0.622 0.200 x0.995
eV eae: +0.042 —0.427 —0.624 0.197 x1.010
NOU S30) ete +0.035 —0.432 —0.627 0.195 x1.020
The collaborative results obtained on samples of milk taken from
individual cows and herds and on a number of samples taken under
pathologic conditions are given in the report of the associate referee.
It was deemed expedient to divide the subject in this manner in order
that the numerous tests made under known conditions and on authentic
samples together with the conclusions drawn therefrom might be pre-
sented in a distinct report. The results obtained on various sets of
samples systematically mixed with known percentages of water are
given in full in Tables 2, 3, 4 and 5.
Included in Table 5 are results obtained on a number of recent
samples (chiefly market milks) which will bear a careful study and
comparison in connection with the general discussion.
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 477
BS.TESTED THERMOMETER
Laboratory Thermometer No. 2.
CORRECTION
7 GRAM 10 GRAM
WATER SUCROSE TO SUCROSE TO
100 cc. 100 cc.
+0.056°C. —0.425°C. —0.621°C.
Interval = 0.196
0.196 equiv. 0.199
Correction = X1.015
Laboratory Thermometer No. 24
7 GRAMS 10 GRAMS
WATER SUCROSE TO SUCROSE TO INTERVAL IEPRESSION ~0. 422°
100 ce. 100 ce. °
0.199. r. SUCROSE 100 cc
EPRESSION -O0.621
0.00°C. —0.420°C. —0.625°C°
Interval = 0.205
0.205 equiv. 0.199
Correction = 0.971
Example:
Laboratory Thermometer No. 24.
F. pt. Depression Sample Milk = 0.548
(0.548 —0.420) 0.971 =0.124
Corrected depression = 0.422 +-0.124 =0.546°C.
SUPERCOOLING
Fic. 1
Note.—Complete lactose determinations were made on all samples by only one of
the collaborators in compliance with the instructions, but these results are not included
in the tables, chiefly for the reason that they do not serve the purposes of the present
stage of our work in the manner anticipated.
DISCUSSION OF RESULTS.
Samples A, B, and C, Table 2, are Holstein milks and are much alike in general com-
position. Following the accepted rules of interpretation of results of the serum exami-
nation, it will be seen that the added water indications are similar in all three series of
mixtures. The cryoscopic tests yield consistent and uniformly agreeing values in all
cases except in the series based on Sample C, in which instance serious irregularities
are apparent among the analytical results obtained on the mixtures containing, re-
spectively, 11, 13, and 15 per cent of added water. Indications point to the possibility
478 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 2.
Milks containing known percentages of added water.
(Connecticut Agricultural Experiment Station.)
CRYOSCOPIC
IMMERSION EXAMINATION
REFRACTOMETER
READINGS 20°C. | 4SH_IN 2 be 52
SPECIFIC SOLIDS ACEC 3 3 IS
ADDED) licnavrayil| FAT! eS SERUM | ADDED WATER iS =8 S
WATER | 156°C. eK (Gram | INDICATED w Fal EeC|s
A in | f
Aortic | Gopper| 10000) ¢ |e] |3g°
m& |< <s
Sample A.—Individual cow—Holstein.
per cent per cent | per cent —0°C. | per cent | per cent
0.545
None | 1.0306} 3.00 } 8.26 | 41.5 | 37.4 | 0.7880) none 0.545 | none | 0.91
0.516
5 | 1.0293] 2.85 | 7.88 | 40.5 | 36.5 | 0.7520) none 0.516 | 5.32] 6.18
0.504
7 | 1.0288] 2.80 | 7.77 | 40.0 | 36.0 | 0.7320) none 0.504] 7.52] 8.36
0.492
9 | 1.0278} 2.75 | 7.51 | 39.4 | 35.7 | 0.7164) none 0.492 | 9.72} 10.54
0.482
11 1.0274| 2.70 | 7.39 | 39.0 | 35.3 | 0.6980) positive 0.482 | 11.55 | 12.36
0.470
13 | 1.0268} 2.65 | 7.24 | 38.5 | 34.9 | 0.6856] positive 0.471 | 13.66 | 14.45
0.460
15 | 1.0263) 2.60 | 7.08 | 37.9 | 34.5 | 0.6736] positive 0.461 | 15.50 | 16.27
Sample B.—Herd, 11 Holsteins—April 13, 1921.
0.535
None: } 1.0313'| 3.70: 8:56) | 41:8] (37-5)... . none 0.535 | none | 2.72
0.505
5 | 1.0298 | 3.50), 8.17 | 40.5.) 36.5.) ven: none 0.505 | 5.60] 8.18
0.494
7 | 1.0286| 3.40] 7.84 | 39.8 | 36.1 }...... none 0.495 | 7.57 | 10.09
0.484
DL O2ZSLie3235 a) e7eVOR|) SS. Seesaw Suspected | 0.484} 9.53 | 12.00
0.472
11 1.0276} 3.30 | 7.56 | 38.9 | 35.3 ]...... positive 0.473 | 11.68 | 14.09
0.462
DSi) 1202700) FSi20) 7418 SSO eas O llc. s c.-s positive 0.462 | 13.64 | 16.00
0.452
15 ate O26G iS HLO oi ei(acel alte occ IN iel sin ae fy positive 0.453 | 15.42 | 17.73
i
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 479
TasBLe 2.—Continued.
Milks containing known percentages of added water.
(Connecticut Agricultural Experiment Station.)
CRYOSCOPIC
pee EXAMINATION
REFRACTOMETER
READINGS 20°C. | ASH IN 3 = aes
SPECIFIC SOLIDS Boeine 3 2s BS)
ADDED | Gravity| FAT not |———7— | SERUM | ADDED WATER 9 Ci] om
WATER | 156°C. FAT (Gram INDICATED % eae by BE 3
Acetic | Copper 100 ec.) 'S te Set Est
Serum | Serum Ey ze 38 =
al < <<
Sample C.—Herd, 11 Holsteins—May 2, 1921.
per cent per cent | per cent —O°C. | per cent | per cent
0.540
None | 1.0305| 3.70 | 8.38 | 40.5 | 37.6 | 0.7396) none 0.540 | none 1.82
0.512
5 1.0287} 3.50 | 7.90 | 39.3 | 36.7 |...... none 0.512] 5.19} 6.91
0.502
7 1.0283 | 3.40 | 7.75 | 39.0 | 36.3 | 0.6936) none 0.502| 7.04] 8.73
0.491
9 1.0277| 3.40 | 7.63 | 38.4 | 35.9 | 0.6724! positive 0.492 | 8.96) 10.63
0.482
int 1.0273 | 3.30 | 7.47 | 38.0 | 35.5 | 0.6544! positive 0.483 | 10.65 | 12.27
0.473
13 1.0270| 3.30 | 7.41 Sarre beta Oe eee positive 0.474 | 12.31 | 13.91*
0.465
15 1.0262} 3.20 | 7.18 | 37.0 | 34.8 | 0.6232) positive 0.466 | 13.79 | 15.36*
* Irregularities in analytical results due probably to inexact preparation of sample or incomplete mixing.
that these samples were not accurately prepared or were imperfectly mixed before
analysis. Owing to the fact that the freezing-point result on Sample B approaches the
highest obtained on authentic samples of milk, a discrepancy is shown, as may be
expected, between the two series of results tabulated in the last two columns. Results
calculated on the basis of the freezing point of the original sample correspond closely
with the known percentages of added water, whereas results calculated on the basis of
the average freezing point of pure milk (—0.550°C.) show discrepancies varying from
2.72 to 3.18 per cent throughout the series. Results are in much closer agreement
with actual composition in the series headed by Sample A, and the same is true in the
series headed by Sample C with the exception of the irregularities pointed out in the
last three mixtures.
The four series of mixtures included in Table 3 afford a more instructive and com-
plete illustration of the relationships among the results obtained by the various methods
applied. The series headed by Sample II-A exhibits a general resemblance to the
series headed by Sample A included in Table 1, except that in the former series the
percentages of added water as determined by the freezing tests are more closely in
agreement with the mixtures of known composition. The series based on Sample
IL-C also exhibits resemblances to the Holstein series included in Table 1 except that
the indications of added water based on the serum examinations are positive almost at
the beginning. The two series based respectively on Samples II-B and II-D are also
very similar. They are illustrative of a type of milk which exhibits striking contrasts
480 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 3.
Samples containing known percentages of added water.
(Libby, McNeill & Libby Laboratory.)
CRYOSCOPIC
IMMERSION DETERMINATION
"READINGS 20°C. | ACETIC 3) | miles
aovep |Gnaviry | par | “Son a ee ce
Aes} 156°C FAT ie 100 | INDICATED s eal 2S
-6°C. i & | oe a416
Sates | SoPEE ass |ze| |38\"
ia < <f
Sample II-A.—Herd, 7 Holsteins.
—0°C.
per cent per cent | per cent 0.550 | per cent | per cent
None | 1.0320| 3.07 | 8.61 | 42.22 | 38.45 | 0.7374; None 0.549 |None | None
0.520
5 | 1.0305 | 2.90 | 8.21 | 40.92 | 37.39 | 0.7248) None 0.519} 5.45] 5.45
0.508
7 | 1.0300 | 2.85 | 8.07 | 40.30 | 36.78 | 0.7160) None 0.509} 7.45] 7.54
0.500
9 1.0294 | 2.78 | 7.91 | 40.00 | 36.30 | 0.7073) None 0.499 | 9.09} 9.18
0.488
11 1.0288 | 2.75 | 7.75 | 39.25 | 35.78 | 0.6946} Probable | 0.488 | 11.19 | 11.27
0.476
13 | 1.0281} 2.70 | 7.56 | 38.61 | 35.41 | 0.6832} Present 0.477 | 13.27 | 13.36
0.466
15 O2 Tone Gone de4 lol S800 130:09) heme Present 0.466 | 15.19 | 15.27
Sample II-B.—Herd, 7 Pure-bred Jerseys.
0.554
None | 1.0344] 5.25 | 9.65 | 46.40 | 39.51 | 0.8172) None 0.554 | None | None
0.525
5 | 1.0329] 5.00 | 9.23 | 44.36 | 38.32 | 0.7672) None 0.525 | 5.32 | 4.54
0.513
7 | 1.0824] 4.90 | 9.08 | 43.68 | 38.00|...... None 0.512} 7.57] 6.82
0.503
9 ,| 1.0817 |-4.83) |. 8.89 || 43.21)... 0.7452) None 0.501} 9.47) 8.73
0.489
11 | 1.0312] 4.65 | 8.73 | 42.40 | 37.38 | 0.7332) None 0.489 | 11.81 | 11.09
0.475
13 |1.03 04} 4.60 | 8.52 | 41.62 | 36.80 | 0.7208) None 0.475 | 14.34 | 13.26*
0.466
15 | 1.0296! 4.50 | 8.30 | 40.98 | 36.43 | 0.7184! None 0.466 | 15.93 | 15.27
Sample II-C.—Herd, 14 Grade Holsteins (P.M. Milkings, August 11-12, 1921).
0.538 | None| 2.18
None | 1.0293] 3.75 | 8.07 | 39.65 | 36.29 | 0.8036) None 0.538 2.18
0.508 | 5.58] 7.64
5 | 1.0280] 3.55 | 7.71 | 38.62 | 35.19 | 0.7672} Probable | 0.508 | 5.58] 7.64
0.498 | 7.44] 9.45
7 | 1.0277} 3.48 | 7.61 | 38.31 | 34.82 | 0.7572) Present 0.497 | 7.62) 9.64
0.487 | 9.48 | 11.45
9 1.0272 | 3.40 | 7.48 | 37.57 | 34.40 | 0.7468) Present 0.487 | 9.48 | 11.45
0.475 | 11.71 | 13.64
11 | 1.0267] 3.29 | 7.33 | 37.07 | 34.18 | 0.7192) Present 0.475 | 11.71 | 13.64
0.465 | 13.57 | 15.45
13 1.0261] 3.23 | 7.17 | 36.64 | 33.57 | 0.7084) Present 0.465 | 13.57 | 15.45
0.454 | 15.61 | 17.45
15 1.0253 | 3.19 | 6.96 | 36.11 | 33.33 | 0.6904! Present 0.453 | 15.80 | 17.64
* Irregularities in analytical results due probably to inexact preparation of sample or incomplete mixing.
1922) HORTVET: CRYOSCOPIC EXAMINATION OF MILK 481
TABLE 3.—Continued.
Samples containing known percentages of added water.
CRYOSCOPIC
IMMERSION DETERMINATION
REFRACTOMETER| ASH IN ~
READINGS 20°C. | ACETI 7 u a)
BESCIIG SOLIDS : aC I ADDED. = | 8, |8s
ADDED | GRAVITY - SERUM 3 = ==
WATER AT FAT (Gran Wesee = = sic
15.6°C eee in 100 | INDICATED we 2 ale SE 2
? * > ood Ze se
Acetic |Copper| ¢-) Sl oF 33 r—)
Serum | Serum S se oo
Ee < <<
Sample II-D.—Herd, 8 Pure-bred Jerseys (P.M. Milkings, August 24-25, 1921).
—0°C. | per cent | per cent
percent BER CERLNIDED cent 0.547 | None} 0.55
None | 1.0313] 4.95 | 8.82 | 42.70 | 37.73 | 0.8268) None 0.546 0.73
0.519 | 5.10| 5.64
5 | 1.0300} 4.68 | 8.44 | 41.15 | 36.59 | 0.7906) None 0.518 |_ 5.13 | 5.82
0.504 | 7.86) 8.36
7 | 1.0295} 4.60 | 8.30 | 40.32 | 36.25 | 0.7792| None 0.504 | 7.69) 8.36
0.493 | 9.87 | 10.36
9 | 1.0289] 4.50 | 8.13 | 39.69 | 35.75 | 0.7620) None 0.493 | 9.71 | 10.36
0.482 | 11.88 | 12.36
11 | 1.0285| 4.46 | 8.02 | 39.18 | 35.32 | 0.7456) None 0.481 | 11.90 | 12.54
0.473 | 13.53 | 14.00
13 | 1.0280} 4.35 | 7.87 | 38.60 | 34.98 | 0.7244) Probable | 0.473 | 13.37 | 14.00
0.462 | 15.54 | 16.00
15 | 1.0276| 4.25 | 7.75 | 38.12 | 34.61 | 0.7112| Present 0.461 | 15.57 | 16.18
in comparison with milk obtained from Holstein herds. In the case of the series II-D,
the refractometer readings taken in conjunction with the ash results on the acetic serum
fail to yield positive indications of added water as high as 13 per cent, and in the case
of II-B no positive indication of added water is observable in any of the mixtures.
Doubtless the series could have been continued so as to include 19 or even 21 per cent
of added water before results of the serum examinations could be interpreted as posi-
tive. Serious irregularities are apparent at the close of this latter series which seem to
render doubtful the calculated percentages included at the bottom of the last two columns.
The general contrasts between the series based on Samples A, B, and C, (Table 2),
and the series based on Samples IJ-A and II-C, (Table 3), on the one hand, and the
series based on Sample II-B and II-D, (Table 3), on the other, may be anticipated
after an inspection of the general results of the analyses, chiefly the results for fat-free
solids. It will be noted that the figures for fat-free solids in the original Holstein
samples range from 8.07 to 8.61, whereas, in the case of the Jersey herd samples, the
fat-free solids figures are respectively 8.82 and 9.65 with the exception of the slight
irregularities observed near the close of the series based on Sample II-B. The results
derived from the freezing-point determinations are reasonably in agreement with the
known composition of the mixtures. The discrepancies between the calculated and
the known percentages range throughout the four series from a minimum of 0.09 to a
maximum of 0.93, omitting the results obtained on the 13 per cent mixture in series
IL-B. Irregularities among results based on the freezing-point determinations may be
due to various factors, among which are improperly prepared samples, gradual changes
in acidity, inaccuracy in manipulation of the freezing-point tests, personal errors, etc.
Nevertheless, in all series of samples added water is positively indicated in each mix-
ture of known composition by means of the cryoscopic test, and the results are suffi-
ciently consistent to justify the conclusion that the indications of added water are
482 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 4.
Milk containing known percentages of added water*.
(Analysts, L. S. Palmer and R. D. Evans.)
IMMERSION
REFRACTOMETER eee
ADDED paavere FAT Sone eT aie ice SEES T-T)100
WATER AT NOL'FAT) || ——— ain nee || LENDICATED point | (T-T’) 106
15.6°C. Acetic Copper T
Serum ecum
per cent _ | per cent per cent -0°C. per cent
Whole
Milk 1.0312 3.25 8.45 44.10 37.85 None 0.544 Eee
5 1.0302 3.15 8.18 42.70 37.4 None 0.516 5.14 ;
7 1.0296 3.00 8.0 41.72 37.00 | None 0.505 (pili
9 1.0288 2.90 7.78 41.20 36.65 | None 0.492 9.55
11 1.0284 2.80 7.66 40.90 36.3 None 0.482 11.21
13 1.0280 2.75 1.59 39.55 35.6 Probable Hos sigue
15 1.0274 2.70 7.39 39.50 35.5 Probable 0.467 14.15
* Cow: Ayrshire from dairy herd, University Farm, St. Paul, Minn.
TABLE 5.
Market milks tested for added water.
CRYOSCOPIC
IMMERSION EXAMINATION
REFRACTOMETER AT ASH IN —————7
NUM- | SPECIFIC SOLIDS 20°C. ACETIC ADDED 8 S
BER OF | GRAVITY FAT an SERUM WATER wo nal
SAMPLE AT rar | S—=«ws~S*«=<i«té‘iSCOC*@Y Gram in| EICATED 55 Eas
15.6°C. Acetic Copper 100 cc.) aS 33 re}
Serum Serum | rane |
35
per cent | per cent —O0°C. } per cent
6720 | 1.0294 3.4 8.17 40.00 SOLO Us ale cacy None 0.5380} 3.64 — ,
6725 | 1.0300 3.5 8.34 40.23 CNL? lt aeons None 0546). i
6793 | 1.0286 3.5 7.99 39.36 36.50 0.7548 | None 0'546)1) kee
6902 | 1.0302 3.6 8.40 AQLOR eee Vee 0.7380 | None 0.516] 6.18
6904 | 1.0302 4.0 8.49 4:66: 9/10. a wee 0.7556 | None 0.5386] .... ;
6955 | 1.0298 3.9 8.38 39.66 36.25 0.7130 | None 0.498 | 9.45 i
6963 | 1.0276 3.8 7.81 38.02 35.00 0.6012 | Present 0.466 | 15.27
6983 | 1.0292 4.3 8.31 40.35 37.00 0.7348 | None 0.533 | 3.09 ’
7012 | 1.0296 3.5 8.25 39.38 36.18 0.7264 0:535 ||" see
7152 | 1.0281 3.5 7.87 38.80 35.78 0.6800 | Present 0.504 | 8.39 ]
1922] HORTVET: CRYOSCOPIC EXAMINATION OF MILK 483
reliable, well below 1 per cent under the conditions exhibited by these mixtures. In
other words, the cryoscopic method is dependable in all cases.
Results based on the average freezing point (—0.550°C.) for normal milk yield some-
what wider discrepancies but in the samples included in this investigation are well
below 3 per cent. The examination of the various serums yields results which are
obviously dependent to a great extent on the composition of the original milk. With
reference to herds it may be concluded in general that milk obtained from Holsteins
is more susceptible to positive indications as a result of serum examination than milk
obtained from Jerseys or other breeds exhibiting similar characteristics. In certain
cases, not necessarily extreme but commonly occurring in many localities, market
milk may actually be highly mixed with water and yet yield no positive indication of
the fact as a result of the refractometer readings or the ash determinations, whereas
such adulteration is immediately apparent as a result of cryoscopic tests even to a
figure as low as approximately 3 per cent. It is conceivable, in fact positively demon-
strated in these results, that certain types of milk may contain as high as 20 per cent
or even more of actual added water without yielding positive indications of adultera-
tion by means of any heretofore applied method of examination, while, on the other
hand, certain other types of milk, derived chiefly from Holstein sources, will yield
positive results in cases of adulteration down to a much lower percentage.
These general conclusions are instructive and should be borne in mind in connection
with the routine examination of market milk. Obviously no sample of milk should be
condemned simply because it happens to yield on analysis a low specific gravity result
or fat-free solids below 8 per cent. Neither can it safely be concluded that a sample is
unsophisticated for the simple reason that it yields serum examination results falling
within the accepted limits. Numerous market milk samples have been unjustifiably
condemned as a result of the ordinary course of analysis, and it is also true that numerous
samples have been passed or merely reported as suspicious as a result of analytical
procedures based on prepared serums. Therefore, as a valuable adjunct to methods
heretofore applied the cryoscopic examination serves a very useful and just purpose,
for the reason that no sample of milk which yields a normal freezing-point result will
be unfairly condemned and, on the other hand, no sample which as a result of general
analysis is apparently normal but at the same time yields an abnormal freezing-point
result can be reported upon favorably. Furthermore, the cryoscopic examination not
only affords a positive indication of adulteration but also yields results in terms of
percentages which may be regarded as reasonably accurate, allowing for tolerances
warranted by an investigation under local conditions.
GENERAL STATEMENT.
It is necessary to make clear what is to be comprehended under the
title—the cryoscopic method. Essentially involved in this method are
the following:
(1) The procedure for testing and correcting the thermometer.
(2) The procedure for making the freezing-point determination, strict attention being
given to the following:
(a) The temperature of the cooling bath;
(b) the degree of supercooling; and
(c) a close adherence to other requirements, among which are quantity of sample,
rate of stirring and the method of using the thermometer.
484 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
The above cryoscopic method does not, so far as can now be stipu-
lated, involve any special design or type of apparatus, but it is important
that all essential conditions be maintained uniform and that the instruc-
tions given in the procedure be strictly followed. In other words, the
cryoscopic procedure, described in detail in the report of the referee for
1920! and subjected to collaborative study during the present year, is
an attempt to standardize the method, and it is therefore understood
that whatever may be the design or type of thermometer or cryoscope
the outlined conditions are to be carefully observed.
RECOMMENDATIONS.
Having in mind the above explanatory statement, it is recommended—
(1) That the cryoscopic method of examination of milk be adopted
as an official method.
(2) That a continued study be made of the cryoscopic method both
as applied to the examination of milk and also as applied as a general
method for the examination of other food products.
CRYOSCOPY OF MILK.
By E. M. Bairey (Agricultural Experiment Station, New Haven, Conn.),
Associate Referee.
This report deals only with the freezing points of authentic samples
of milk from individual cows and herds as outlined in the schedule of
study for 1921, with certain additions thereto.
Two hundred sixteen samples are represented in the combined reports.
Partial or complete analyses with freezing-point determinations, the
latter largely in duplicate, were made. These were classified in appro-
priate groups and the results appear in tabular form in Tables 1, 2, 3
and 4.
1 J. Assoc. Official Agr. Chemists, 1921, 5: 172.
1922] BAILEY: CRYOSCOPY OF MILK 485
TABLE 1.
Analyses and freezing-point depressions of authentic milk.
(NORMAL INDIVIDUAL COWS.)
wae
sos SPECIFIC nd 3 »
aoa GRAVITY iP z 5 FREEZING
HERD 523 BREED DATE 1921 AT FAT! 24 = ASH a POINT:
Sis 15.6°C. 29] 2 g
zo< P|
=O@D
Collaborator, Libby, McNeill § Libby
per | per per per per
cent | cent cent | cent cent —0°C.
EGaie 4B | Holstein 9-14 P. M.| 1.0306) 3.3 | 8.30) 4.64 | 0.639) 0.145) 0.532 0.531
H. A. 5B 1.0310) 3.6 | 8.47) 3.71 | 0.799) 0.147) 0.551 0.551
HievA: 6B 1.0380) 3.8 | 10.26) 3.65 | 0.805) 0.155) 0.566 0.566
B.J.F.| 7B 1.0300) 3.3 | 8.15) 4.39 | 0.660) 0.140) 0.533 0.533
1 Holstein,'Grade|9-18 P. M.| 1.0260) 6.3 | 7.76) 3.41 | 0.664/ 0.120) 0.548 0.549
7 1.0303) 4.9 | 8.55) 4.45 | 0.697) 0.170) 0.548 0.546
8 1.0264] 3.0 | 7.20) 4.29 | 0.770) 0.103) 0.548 0.548
9 1.0303) 3.8 | 8.34! 4.37 | 0.678) 0.165) 0.538 0.537
11 1.0288) 4.7 | 8.14) 4.16 | 0.728) 0.153) 0.549 0.548
133d ON hae Holstein, Pure |9-14 P. M.| 1.0300} 2.2 | 7.90) 4.38 | 0.693) 0.140) 0.535 0.535
BV: Holstein, Grade}9-16 P.M.| 1.0287! 0.9*| 7.36) 4.15 | 0.719) 0.100) 0.538 0.537
A. H. 9-21 P.M.) 1.0357} 3.3 | 10.01) 4.17 | 0.784/ 0.190) 0.548 0.548
J.N. 1.0316) 3.7 | 8.63) 4.34 | 0.707| 0.153) 0.551 0.550
B.F.H. 1.0338] 4.1 | 9.26) 4.15 | 0.770) 0.165) 0.549 0.548
E. K. Jersey, Grade 1.0328) 4.3 | 9.05) 4.68 | 0.730) 0.165) 0.542 0.540
Aposl 9-26 A. M.| 1.0326) 3.1 | 8.77) 5.03 | 0.628) 0.115) 0.560 0.560
9-26 P. M.| 1.0320} 2.8 | 8.57) 4.78 | 0.622) 0.118) 0.546 0.545
5 | BrownSwiss /|9-18 P. M.| 1.0256) 5.3 | 7.46) 3.65 | 0.647) 0.145) 0.549 0.548
A. M. Durham, Grade|9-16 P. M.| 1.0310) 3.5 | 8.44) 4.55 | 0.661) 0.145) 0.533 0.533
A.S. 1.0328} 4.0 | 8.99} 4.61 | 0.676) 0.160) 0.545 0.547
GT. 9-26 A. M.| 1.0318} 4.0 | 8.74) 3.75 | 0.782) 0.110) 0.548 0.549
9-26 P.M] 1.0310} 4.3 | 8.60) 3.56 | 0.797 0.120) 0.541 0.540
A.D. Durham—S. /9-26 A.M. 1.0340! 4.9 | 9.48) 4.63 | 0.829) 0.135] 0.550 0.550
Horn 9-26 P. M.| 1.0340) 4.4 | 9.37) 4.52 | 0.832) 0.123) 0.548 0.547
O.R. Short Horn— |9-26 A.M.) 1.0325) 4.6 | 9.05) 3.63 | 0.636) 0.083) 0.540 0.539
Holstein 9-26 P. M.| 1.0326] 4.2 | 8.96) 3.43 | 0.661) 0.080) 0.540 0.540
F.F. Red Pole 9-23 A. M.| 1.0304] 5.5 | 8.94! 4.53 | 0.695) 0.138) 0.551 0.551
Collaborator, Minnesota Dairy and Food Department.
Bees <3 1H _ | Holstein, Reg. |5-9 TE OZO5 aeval tea alias o silane tel |OsoOU resp
Per 2. 2H. TECUPAST GOA ts) es Sa tees [ale me (Isis deers
BES > 3H MOS TOUS 4 tas 8a o-oo cl tees | Olam OL rier.
BAe 15 4H TORE GACY otshise a [ee ire lele ese Rae 74 Be
ier = ors TOSLO| 235 | Sede less ave | ergs =| (Oz ekO rer ane
Rise 6230 | Holstein 5-14 1.0305) 3.3 | 8.57)..... pe ae Uae es ete
bie x, 6231 THOS TO AS |e Koper RR a Te hl aie aE Cl Pics Oe
Bee oh 6232 TAO SUE)| Debs yey |cchahe AS Ne ea LEMS? ice eee
tec 4 6233 1 G320) (2:2 eS OOl ee celeriac aera O:2On eer
ee. 27 6234 MOSSO 2 Sales OD ease donee des Osan recy
it 2 6235 HEOSTONDIG teSeeale ee cee nacee| Oso00 mers.
Baie dy 6236 HOSTS OM eOOd os scl coeele mse Ola02, ccna
Tae 6237 MOSSONS 3 nO OSes alls seal esters O soe beers
ce 6238 AOSTOWATA er ScaSloe celce Solan Oot lrtan
ae 6250 5-17 TDA OE et te el eee lenioeal Une 83).¢ odie
Bee de 7022 | Durham 9-7 MOS2S 4A OO eae sec O-Opaaet eres
St.L.P.| .... | (Br. not given) |8-25 1.0315] 3/8 | 8-80)... .. Deere) by aa 0:51 ero
* A.M. sample following day tested 1.6% fat.
486 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
Tasie 1.—Continued.
[Vol. V, No. 4
Analyses and freezing-point depressions of authentic milk.
(NORMAL INDIVIDUAL COWS—Continued.)
* See discussion.
—— ae
yee
shiz SPECIFIC a& | »
aoa GRAVITY on [} 5 FREEZING
HERD 5 z 2 BREED DATE 1921 AT FAT 2 & 5 ASH a POINT
5 bab 15.6°C. ae| 4 S
- OD
Collaborator, Connecticut Agricultural Experiment Station.
per | per | per per
cent | cent | cent | cent | cent -0°C.
as 1 | Holstein 4-5 A.M.| 1.0323] 3.6 | 8.80)....)..... 0.17 | 0.573 0.574*
4-13 A.M.) 1.0317) 3.2 | 8.58)... .)..... 0.15 | 0.558 0.559
4-15 A. M.| 1.0330} 3.3 | 8.92)....]..... 0.16 [0.565 0.566
1.0330) 3.3 | 8.92)....]....- 0.15 | 0.565 0.565
4-16 A. M.| 1.0322) 3.4 | 8.74)....]..... 0.16 | 0.565 0.565
4-20 A. M.| 1.0315] 3.3 | 8.55)....)..... 0.15 | 0.562 0.562
4-20 P. M.| 1.0305) 3.3 | 8.30)....]..... 0.14 | 0.542 0.542
5-20 P. M.| 1.0299] 3.4 | 8.17)....]..... 0.14 | 0.536 0.537
2 4-6 A.M.) 1.0320) 4.3 | 8.88)....]..... 0.14 |0.572 0.572*
4-13 A. M.| 1.0311) 3.4 | 8.46)....]..... 0.15 | 0.544 0.544
4-16 A. M.| 1.0317} 4.1 | 8.76]....]..... 0.14 | 0.562 0.562
4-20 A. M.} 1.0317) 3.6 | 8.67]....]..... 0.13 | 0.553 0.554
4-26 P. M.} 1.0307) 3.8 | 8.46]....)..... 0.15 | 0.547 0.546
5-18 P. M.| 1.0309) 4.3 | 8.60)....]..... 0.13 | 0.551 0.552
3 4-7 A.M.) 1.0337] 5.4 | 9.54)....]..... 0.15 | 0.572 0.572*
4-13 A.M.| 1.0321) 4.7 | 8.98)... .]..... 0.15 | 0.557 0.557
4-20 A. M./ 1.0330) 5.1 | 9.29)....]..... 0.15 | 0.562 0.563
4-26 P. M.| 1.0325] 5.0 |9.14)....]..... 0.14 | 0.547 0.547
5-20 P. M.| 1.0332) 5.0 | 9.31)....]..... 0.15 | 0.549 0.550
4 4-9 A.M] 1.0308) 4.4 | 8.60)....]..... 0.12 | 0.560 0.560
4-20 A. M.] 1.0320) 3.6 | 8.73)....]..... 0.14 | 0.562 0.562
49 P.M.| 1.0299) 4.4 |8.37|....]..... 0.12 | 0.552 0.550
4-26 P. M.| 1.0308) 3.1 | 8.34)....]..... 0.15 | 0.543 0.543
5-26 P. M.} 1.0315) 3.3 | 8.85]... .)..... 0.13 | 0.543 0.543
5 4-8 A.M.| 1.0333] 3.7 |9.07]....]..... 0.15 | 0.552 0.552
6 4-16 A. M.| 1.0326} 3.3 | 8.82]....}..... 0.12 |0.571 0.571*
4-22 A.M.} 1.0313} 3.5 | 8.52)....]..... 0.11 |0.571 0.571
4-25 P. M.| 1.0301] 3.1 | 8.15)....}..... 0.11 | 0.533 0.534
4-26 P. M.| 1.0309] 3.7 | 8.48)....]..... 0.10 | 0.544 0.545
7 4-22 A.M.| 1.0322) 4.0 | 8.85]....]..... 0.12 | 0.571 0.571*
4-25 P. M.| 1.0312} 4.0 | 8.60)....|..... 0.11 | 0.545 0.546
5-26 P. M.| 1.0326} 4.3 | 9.03)....)..... 0.12 | 0.553 0.553
8 4-22 A. M.| 1.0342) 4.6 | 9.48)....]..... 0.13 | 0.580 0.580*
4-25 P. M.| 1.0333) 4.0 | 9.13)....]..... 0.12 | 0.542 0.542
5-18 P. M.| 1.0343} 5.0 | 9.58)....]..... 0.11 | 0.552 0.553
9 4-22 A. M.! 1.0340) 3.8 | 9.28]....]..... 0.15 | 0.571 0.571*
4-25 P. M.| 1.0317] 4.7 | 8.90)....]..... 0.12 | 0.543 0.544
5-18 P. M.| 1.0318} 4.6 | 8.94)....)..... 0.12 |0.551 0.552
10 4-22 A. M.| 1.0320) 4.1 | 8.83)....|..... 0.15 | 0.572 0.572*
5-18 P. M.| 1.0301] 4.0 | 8.33)....)..... 0.12 | 0.542 0.542
ll 4-22 A.M.| 1.0320} 3.7 | 8.75)....)..... 0.15 | 0.562 0.562
5-18 P. M.| 1.0303] 3.9 | 8.35)....)..... 0.15 |. 0.543
1922] BAILEY: CRYOSCOPY OF MILK 487
Tasie 1.—Continued.
Analyses and freezing-point depressions of authentic milk.
(NORMAL INDIVIDUAL COWS—Continued.)
z 6 g SPECIFIC n& a oe
asa GRAVITY Be | oo ‘3 FREEZING
HERD 5S z3 BREED DATE 1921 AT FAT 2 a 5 ASH a POINT
5 3 ; 15.6°C. 29/4 g
Collaborator, Connecticut Agricultural Experiment Station—Continued.
per | per | per | per | per
cent | cent | cent | cent | cent -0°C.
ay; 12 | Holstein 4-23 A.M.| 1.0301} 6.8 | 8.88]... .]..... 0.16 |0.572 0.572*
5-18 P. M.} 1.0327] 6.5 | 9.47]....)..... OVS) |i cee OLE
13+ 4-23 A.M.) 1.0304] 3.8 | 8.37]... .]..... 0.12 |0.540 0.540
5-26 P. M.} 1.0316} 4.6 | 8.84]....}..... 0.12] .....: 0.542
14 4-23 A.M.] 1.0319} 3.8 | 8.75)....)..... 0.16 | 0.549 0.549
5-20 P. M.} 1.0320} 4.0] 8.81]....)..... 0.16 | 0.539 0.538
15 4-27 A.M.} 1.0317] 3.5 | 8.65]....]..... 0.11 |0.561 0.561*
4-25 P. M.| 1.0298} 3.0] 8.76)....]..... 0.13 | 0.523 0.523
4-26 P. M.} 1.0305) 3.3 | 8.30]....]..... 0.14 | 0.532 0.532
4-27 P. M.| 1.0301) 3.2 | 8.17)....]..... 0.13 | 0.536 0.537
5-20 P. M.} 1.0312] 3.4 | 8.48]....)..... 0.13 | 0.544 0.545
16 4-26 P. M.| 1.0302) 4.5 | 8.45]....)..... 0.16 |0.540 0.541
5-20 P. M.| 1.0317| 4.6 | 8.87)....]..... 0.16|..... 0.542
17 4-26 P. M.| 1.0294) 3.5 | 8.06]....]..... 0.13 | 0.541 0.541
5-20 P. M.| 1.0291) 3.5 | 7.98]....]..... OND ceme (02542
F. 1 4-16 A.M.} 1.0310) 3.2 |8.40)....]..... 0.14 | 0.542 0.542
5-6 P.M.) 1.0304] 3.1 | 8.23)....)..... 0.14 |0.541 0.541
2 4-18 A. M./ 1.0313] 2.8 | 8.38]... .]..... 0.15 | 0.542 0.542
aay. AY POPS Billo dpisl |e coml anes 0.14 | 0.543 0.544
3 A—USEAY VEE OS29 cvsxcy| iuceane|loncteve siese lore 0.14 | 0.550 0.551
5-5 P.M.| 1.0296] 3.2|8.05)....)..... 0.14 | 0.532 0.533
4 4-18 A. M.| 1.0308] 3.1 | 8.34]... .)..... 0.15 | 0.542 0.543
5-5 P.M.) 1.0301) 3.2|8.17|....)..... 0.15 | 0.529 0.530
5 4-18 A. M.| 1.0318) 3.4 | 8.64)....]..... 0.16 | 0.543 0.543
5-5 PP. M:) 10317), 3.5 8.64). ...|.. ... 0.16 | 0.542 0.540
6 ‘4-19 A. M./ 1.0280) 4.0] 7.81]....}..... 0.11 | 0.545 0.546
5-5 P.M.| 1.0307] 4.0 | 8.50)...+]..... 0.13 | 0.541 0.542
7 4-19 A. M.} 1.0323] 4.1 |8.90)....]..... 0.14 | 0.552 0.552
LSI Els ogee tO! |lerserl latter. 0.11 | 0.542 0.542
8 4-19 A. M.| 1.0335] 4.8 | 9.35)....]..... 0.14 | 0.548 0.549
5-6 P.M.) 1.0310) 2:9 | 8.33)....)..... 0.16 | 0.536 0.536
9 4-19 A.M.| 1.0298) 3.8 | 8.23)... .)..... 0.15 |0.542 0.542
5-6 P.M.) 1.0305] 3.8 | 8.40)....]..... 0.14 | 0.534 0.534
10 4-19 A.:M.| 1.0309] 3.8 | 8.50]....]..... 0.13 | 0.547 0.547
5-6 P. M.| POSUO ost SesOie ° .|ince -.- 0.12 | 0.543 0.543
11 4-19 A.M.| 1.0301) 3.5 | 8.23)....)..... 0.16 | 0.542 0.542
5=6) PME. 0303)2-7,|\8:LON. cc |b ons. - 0.17 | 0.535 0.535
488 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Tasie 1.—Concluded.
Analyses and freezing-point depressions of authentic milk.
(NORMAL INDIVIDUAL COWS—Concluded.)
286 =|)
D Zz SPECIFIC ne a >
HERD 5 g 2 BREED DATE 1921 raid FAT 5 = ASH 4 Spe
e z 4 15.6°C. ag] 3
Collaborator, Connecticut Agricultural Experiment Station—Concluded.
per | per | per | per per
cent | cent | cent | cent | cent -0°C,
1 | Jersey 4-29 A. M.| 1.0336) 6.0 | 9.63]....]..... 0.17 | 0.542 0.543
2 | Ayrshire 4-29 A.M.| 1.0309) 4.1 | 8.56)... .]..... 0.18 | 0.531 0.532
3 | Guernsey 4-29 A.M./ 1.0309) 5.1|8.77]....]..... 0.20 | 0.549 0.549
5 | (Br. not given) |5-11 P. M.| 1.0320] 3.7 | 8.75}....|..... 0.16 | 0.532 0.533
7-6) PAINT 10308) .427)|'8:bp|> oleae 0.14 | 0.5385 0.536
6 | (Br. not given) |5-11 P. M.| 1.0309}....}.... ara opel taeetceeae 0.09 | 0.542 0.542
7-6) avi eZ altoes.|@eooile seal ae 0.09 | 0.535 0.535
TABLE 2.
Analyses and freezing-point depressions of authentic milk.
(NORMAL HERDS.)
SPECIFIC tll es 2
ERD |e BREED DATE 1921 |GRAVITY| par | 2* | 2 ASH = FREEZING
cows AT 3 K g 5 POINT
15.6°C. as =I <
Collaborator, Libby, McNeill § Libby.
per per per per per
cent | cent | cent | cent | cent -0°C.
E. M 4 | Holstein,Gradej4-1 P.M.| 1.0314) 3.6 | 8.56)... .)..... 0.145) 0.535 0.534
Wie: nA eee Aas pe 4-1) PLM) 1:0305)'2.8.)'8.07))...- |... <5. 0.145} 0.530 0.531
War VS Dili aps tes cc taearene 6-22 P. M.| 1.0300) 3.1 | 8.13) 4.46}. .... 0.140) 0.541 0.541
Wit, VOB et Clebic's caer oats 7-14 P.M.) 1.0304! 3.3 | 8.26)....)..... 0.135} 0.538 0.538
G.H TES g itera Sabai Sa 3-29 P. M.| 1.0290} 3.6 | 7.98)....}..... 0.135} 0.532 0.5382 ~
G.H 1]10 4 os Bee roto 7-14 P.M.) 1.0295} 3.3 | 8.03] 4.58)... .. 0.135} 0.541 0.541
W.B Geer cy fevavs cisvearnaye 4-1, P.M.) 1.0324), 2-7 | 8:63)... .|..... 0.150) 0.529 0.530
W.B 13 | Holstein, Grade
and pure. 6-22 P. M.| 1.0310} 3.0 | 8.36] 4.72)..... 0.135] 0.539 0.537 —
W.B rey fee ee 7-14 P. M.| 1.0295] 3.2|8.01]....]..... 0.130] 0.533 0.532 j
A.G 15 | Holstein, Pure |8-2 P.M.) 1.0294) 3.4] 8.02)....]..... 0.135) 0.538 0.537
M.B 16 | Holstein, Grade\9-16 P. M.| 1.0313) 3.5 | 8.53) 4.44! 0.722) 0.150} 0.547 0.548 {
H. W ALY ile ey. Beets sok ous eis 9-21 P. M.| 1.0323) 3.2 | 8.72) 4.18] 0.734] 0.143] 0.552 0.552
O.R LOM sce: uke cee 9-26 A. M.| 1.0292) 4.3 | 8.16] 4.29| 0.678) 0.123) 0.534 0.532 j
9-26 P. M.| 1.0285] 4.3 | 7.98] 3.69] 0.710) 0.110] 0.5382 0.533
G. “eV Gh tilt eterssee rece crtate 9-21 P. M.| 1.0313} 3.5 | 8.53} 4.23] 0.696] 0.133] 0.551 0.551 —
D.F.M. 7
1B. 3 | Holstein, Pure |9-14 P. M.| 1.0336) 3.4 | 9.08) 4.53) 0.693] 0.145) 0.550 0.550
BJ.F.
3B. 3 0 Rea ek a Sih Se 9-14 P. M.| 1.0300) 2.7 | 8.05) 4.39] 0.676) 0.145) 0.535 0.535
S. W. 2 | Holstein-Jersey)9-16 P.M.) 1.0313) 3.7 | 8.57| 4.61) 0.684) 0.155] 0.549 0.548
1922] BAILEY: CRYOSCOPY OF MILK 489
TaBie 2.—Concluded.
Analyses and freezing-point depressions of authentic milk.
(NORMAL HERDS—Concluded.)
a SPECIFIC Zz = | z
HERD | NO.OF BREED DATE 1921 |GRAVITY! rar | 3 = ASH a ct et
15.6°C. as |< g
Collaborator, Libby, McNeill & Libby—Concluded.
per | per | per | per per
cent | cent | cent | cent cent —0°C.
Be Vi 11 | Holstein 10,
Jersey 1 9-16 P. M.| 1.0301) 3.1 | 8.15) 4.47| 0.686) 0.145) 0.550 0.549
A.P.T.| 10 | Holstein 4, Jer-
sey 1, Black
Pole 1, Dur-
ham 2, Here-
ford 1, Guer-
nsey 1 9-21 P. M.) 1.0319} 3.5 | 8.68) 4.42) 0.710) 0.140) 0.546 0.545
B.K. 12 | Holstein 2, Jer- \
sey 10 9-21 P.M.) 1.0320) 3.8 | 8.76) 4.52) 0.704) 0.148) 0.543 0.542
Bey 9 | Holstein 7, Red
Pole 1, Jersey 1)9-23 A. M.| 1.0309} 4.2 | 8.56] 4.59] 0.666) 0.148) 0.547 0.545
DIL. 2 | Jersey, Grade |6—22 P. M.| 1.0329) 5.4 | 9.30) 4.92]... .. 0.142} 0.550 0.549
dee las Dio gie ey icv ok slates! —1 P.M.) 1.0316} 3.3 | 8.56] 4.82)..... 0.130) 0.551 0.551
R.N. 6 | Jersey 1, Short
Horn 5 9-21 P.M.) 1.0316} 3.8 | 8.66/4.67 |0.672| 0.150) 0.550 0.550
B. 10 | Durham, Grade|3-29 P. M.| 1.0321) 3.8 | 8.77|....|..... 0.143} 0.542 0.541
/ SDE 6 | Durham-Short
Horn 9-26 A. M.| 1.0325) 4.6 | 9.05] 4.52) 0.687| 0.105} 0.540 0.539
9-26 P. M.| 1.0325} 4.2 | 8.96| 4.50) 0.700) 0.123) 0.540 0.540
PW: 7 |Reds, Grade |6-20 P. M.| 1.0322) 3.9 | 8.83] 4.68)..... 0.157) 0.531 0.531
BE Wi 1 ee a el ee Oe 7-14 P. M.| 1.0324} 3.7 | 8.84)... .]..... 0.130} 0.534 0.533
B. L. 4 |Short Horn,
Grade 9-23 A.M.) 1.0314) 3.6 | 8.57) 4.48) 0.706] 0.150) 0.557 0.556
B. W. 16 | Mixed Grade /6-20 P. M.| 1.0326) 3.7 | 8.98 4.45)... .. 0.152| 0.536 0.537
yee. iis SONS een aera ie 9-26 A. M./ 1.0318} 4.0 | 8.74) 4.68) 0.696] 0.118) 0.548 0.549
9-26 P. M.| 1.0310} 4.3 | 8.60) 4.55] 0.698] 0.120) 0.541 0.540
GT. OMe lepslackevs se sinie @ 1s = 9-26 A. M.| 1.0313} 4.5 | 8.73] 4.29] 0.719] 0.128} 0.552 0.553
9-26 P. M.| 1.0313} 4.1 | 8.65] 4.14) 0.750) 0.125} 0.552 0.553
Factory 9-23 A.M.
Sample | 2300 | Mixed & P.M. | 1.0310} 3.7 | 8.49} 4.45] 0.704| 0.145) 0.541 0.540
Collaborator, Connecticut Agricultural Experiment Station.
Yi 17 | Holstein 4-27 A.M.| 1.0317] 4.1] 8.77)}....]..... 0.13 | 0.553 0.553
4-27 P. M.| 1.0309} 3.5 | 8.44)....]..... 0.14 | 0.539 0.540
F. AL itt ae sel th: 5-2 A.M.) 1.0312) 3.3 | 8.46)....)..... 0.16 | 0.559 0.560
4-13 P. M.| 1.0313} 3.7 | 8.56]....)...-. 0.15 | 0.535 0.535
4-18 P. M.| 1.0309} 3.7 | 8.48)... .]..... 0.16 | 0.539 0.540
4-19 P. M|1.0310| 3.4|8.44]....|..... 0.15 | 0.540 0.540
5-2 P.M.) 1.0305) 3.7 | 8.38)... .|...-.- 0.14 | 0.540 0.540
S. ha ide eels ESE crea ete 4 CW 2 eee eee 0.13 | 0.542 0.542
B. 2 | oe lence Brym Nees Syd Benen eee Pea 0.13 | 0.550 0.550
490 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
TABLE 3.
Analyses and freezing-point depressions of authentic milk.
(Healthy cows under abnormal conditions of daily routine or environment.)
SPECIFIC 2 < z
ATE OF
HERD eee Woot DESCRIPTION Seances FAT Ze 5
15.6°C. n> 3
Collaborator, Libby, McNeill ¢ Libby.
per | per | per
cent | cent | cent
Individual Cows.
A. M., |8-30 P. M.| Pure Jersey, driven 4
2A blocks to Fair, milk-
ing delayed 1 hour. .| 1.0327| 7.6 | 9.69) 4.29
2B 9-14 P. M.| Same cow, normal con-
Gitions:.)7 a ee ee 1.0398} 7.0 | 11.34] 1.80
H. T., |8-30 P. M.| Pure Holstein, driven 6
4A miles to Fair, milking
delayed 31% hours... .| 1.0294] 4.1 | 8.18) 4.52
4B 9-14 P. M.| Same cow, normal con-
ditions] se eee 1.0306) 3.3 | 8.30) 4.64
H. A., {8-31 P.M.) Pure Holstein, milking
5A delayed 1014 hours. . .| 1.0322) 3.9 | 8.84| 4.00
5B 9-14 P. M.| Same cow, normal con-
ditions! ser eee 1.0310} 3.6 | 8.47) 3.71
.A.. |8-31 P. M.| Pure Holstein, milking
6A delayed 101% hours. . .| 1.0358) 5.5 | 10.05) 4.25
6B 9-14 P. M.| Same cow, normal con-
ditions rhea tee 1.0380) 3.8 | 10.26) 3.65
B. J. F.|8-31 P. M.) Pure Holstein, milking
7A. delayed 914 hours. .. .| 1.0270) 3.8 | 7.51) 3.67
7B 9-14 P. M.| Same cow, normal con-
ditions hese 1.0300] 3.3 | 8.15) 4.39
Herds.
D.F.M.|8-30 P. M.| Three pure Holsteins,
1A driven 6 miles to Fair,
arriving 7:30 A. M.
Sample taken from
evening milking... . .| 1.0318] 5.48] 9.05) 4.59
1B 9-14 P.M.|Same herd, normal
conditions. hh ok 1.0336) 3.40) 9.08) 4.53
B. J. F.|8-30 P.M.) Two pure Holsteins,
3A driven 5 miles to Fair,
arriving 7:30 A. M.
Sample taken from
evening milking..... 1.0316) 3.3 | 8.55 | 4.59
3B 9-14 P. M.| Same herd, normal con-
ditions's ts 62.6 oe 1.0300} 2.7 | 8.05) 4.39
>
D
foo)
ACIDITY
0.817) * | 0.563
0.874| 0.160) 0.562
0.666) * | 0.547
0.639} 0.145) 0.532
0.815) * | 0.578
0.799} 0.147] 0.551
0.808) * | 0.563
0.805) 0.155] 0.566
0.732} * | 0.537
0.660) 0.140} 0.533
0.762} * | 0.571
0.693} 0.145} 0.550
0.700) * | 0.561
0.676) 0.145) 0.535
* Freezing point observed same evening that samples were taken.
[Vol. V, No. 4
FREEZING
POINT
-0°c.
0.563
0.563
0.546
0.531
0.577
0.551
0.562
0.566
0.537
0.533
0.571
0.550
0.560
0.535
1922}
HERD
OR NO. |MILKING, 1921
wo bv
Lil
P2
P3
P4
9-18 P.
9-19 A.
9-18 P.
9-18 P.
9-18 P.
9-18 P.
9-19 A.
9-18 P.
SIS TP.
7-13 A.
7-14 A
9-14 P.
9-18 P.
5-11 P.
7-6 P.
5-11 P.
76 P.
5-11 P.
2-6. .P-
5-11 P.
7-6 P.
BAILEY: CRYOSCOPY OF MILK 491
TABLE 4.
Analyses and freezing-point depressions of authentic milk.
(Cows diseased or otherwise abnormal physically.)
eecrere nk 2 z
DATE OF DESCRIPTION GRAVITY) pay | == ° ASH os FREEZING
AT S& & 5 POINT
15.6°C. zo |< g
Collaborator, Libby, McNeill § Libby.
| per | per | per | per per
Individual Gows: cent | cent | cent| cent | cent -0°C.
M.| Pure Holstein, tuber-
cular reactor........ 1.0263) 4.0 | 7.38) 3.10) 0.763) 0.137| 0.550 0.549
M.| Grade Holstein, tu- |
bercular reactor, not
milked evening of
previous day........ 1.0265] 3.3 | 7.28] 2.41) 0.790) 0.100) 0.555 0.556
M.| Grade Holstein, tu- |
bercular reactor. . .. .| 1.0298) 3.4 | 8.13) 2.41| 0.731!) 0.130) 0.560 0.560
M.| Grade Holstein, tu-
bercular reactor... .. 1.0286) 4.5 | 8.05) 4.04) 0.698) 0.170} 0.544 0.543
M.| Pure Holstein, tubercu-
larareactor,.-.c2: 5): 1.0280) 4.6 | 7.92) 4.17| 0.661) 0.155) 0.550 0.550
M.! Pure Holstein, tubercu-
lariredctorse st ace ee 1.0240 3.2 | 6.64) 3.12/ 0.697) 0.090) 0.536 0.535
M.) Pure Holstein, tubercu-
larjreactor.... +2. 4. - 1.0364) 3.7 | 7.34) 2.80) 0.782) 0.100) 0.551 0.549
M.| Guernsey-Holstein, tu-
bercular reactor. . .. .| 1.0299] 4.7 | 8.42) 2.67) 0.714| 0.145] 0.550 0.552
M.| Grade Guernsey, tu-
bercular reactor. .... 1.0270) 4.6 | 7.67| 2.96) 0.767) 0.136) 0.542 0.543
M.| Grade Jersey, poor
physical condition . . .| 1.0286) 3.6 | 7.91)....)..... 0.123) 0.522 0.523
. M.| Symptoms of tubercu-
BORIS flesh oe. Seba llneevee Boe (Sal IRE ete 0.132) 0.523 0.523
M.) Jersey, colostrum milk | 1.0398) 7.0 | 11.34| 1.80) 0.874/ 0.160) 0.562 0.563
|
Herd.
M.| 14 cows, mixed breeds,
8 tubercular......... 1.0272) 4.2 | 7.64) 3.65) 0.716) 0.133) 0.548 0.548
Collaborator, Connecticut Agricultural Experiment Station.
M.) Holstein, tubercular ‘
Teactore. eM Ress . 1:0300]'327- | SS25 |e att..< 0.14 | 0.522 0.522
M WO2ZT21 4 Ay 769i. )ermce 0.12 | 0.5387 0.538
M.| Holstein, tubercular
RCAGLOL 2 ci. Seis ous fapere 1:0304}'2:0)| (8/00) - 5:2). er 0.14 | 0.519 0.520
M 1.0215} 9.5 | 7.38}... 0.13 | 0.534 0.535
M.| Holstein, tubercular
MEACTOLE nt. cee. a0- ODS TI eae -|aeleeal'- 2-2 |e Aakers 0.12 | 0.522 0.522
M 1.0286) 4.0 | 7.96). 0.18 | 0.550 0.552
M.) Holstein, tubercular
TEACION corer crac 1.0304) 4.0 | 8.41)....]..... 0.15 | 0.537 0.538
WE WHolstem: foc 5. occ 4.2 | 7.78 0.13 | 0.541 0.541
1.0277]
492 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Tasie 4.—Concluded.
Analyses and freezing-point depressions of authentic milk.
(Cows diseased or otherwise abnormal physically.)
SPECIFIC a% 2 x
HERD DATE OF DESCRIPTION GRAVITY FAT 8 me g ASH 5 FREEZING
OR NO. |MILKING, 1921 AT 3 & 5 3 POINT
15.6°C. 29 = <
Collaborator, Minnesota State Dairy and Food Department.
99 i i er r er er er
BG eee ah coeiee et gent| gent | cent| cont | Gent | OPC.
ACLOL! Shasta ALOSOU Ste Sceole secs |eeaeee | eee 0.551
518 |9-22 Tubercular reactor, 10
years/Old)..2.285.5 4.2 1 O28 1/219. | eldest mick elexee = els eletere 0.541
519 |9-22 Heifer, 3 years old, tu-
bercular reactor..... 10284)(3288| 8:00] hee one eee O!548. (8s.
520 |9-22 Tubercular reactor... .| 1.0295} 3.6 | 8.23)....].....]..... 1544)
521 |9-22 Tubercular reactor,
wild cow, one eye
blind $= eee a 150328)'3:6n)| 4.0: 0D|-, feral | eee 0.547) 2:
522 |9-22 Tubercular reactor,
produced 30 pounds
of 80% butter in 7
consecutive days..... TOZOS Se | Oc Osl epee | eee el eee 0.543
523 |9-22 Tubercular reactor... .| 1.0303) 4.4 | 8.60)....].....]..... 0.543
524 |9-22 Tubercular reactor. . . .| 1.0328] 3.3 | 9.00)....).....]....- 0.534
525 |9-22 Tubercular cow with
infected udder. .. . . ...| 1:0254]'0.5)| 6.59)... J. 2. -]- 2: 0.586
526 |9-22 Tubercular reactor... .| 1.0290} 3.7 | 8.23)....].....]....- 0.540
513 |9-17 Holstein, calved 7 days
previous to sampling,
infected, still dis-
charges pus......... 1.0294)'4°5 0 78-40) elected eee 0.554 .....
514 |9-17 Guernsey, abortion 11
days previous to sam-
Fa Hyg A A ek 10341403) | Ovo Si teee are eee 0538 tee
DISCUSSION OF RESULTS.
The term ‘‘normal’’ as applied to an individual cow or herd, is used to refer to ani-
mals which, in the judgment of the usual observer or dairyman, would be clessed as
healthy and which are fed and kept with ordinary care. It does not refer to animals
which have been subject to clinical tests and pronounced sound by expert authority.
The milk from animals which conform to this interpretation of the term is presumed to
be normal milk. E
Before taking up the discussion of freezing-point range, as shown by the combined
data, attention is directed to certain extreme results which lie outside the experience
of the collaborators as a whole. This refers to results below —0.570°C. found for a
number of morning samples and to one extremely high figure, —0.523°C. observed in
one case of evening milk from Holstein cows, Herd Y, summarized from Table 1, as
follows:
1922] BAILEY: CRYOSCOPY OF MILK 493
TABLE 5.
Results requiring further corroboration.
FREEZING
cow, DATE POINT,
NO. °C
1 4-5 A.M. O57"
2 46 A.M.| 0.572
3 47 A.M.| 0.572
6 4-16 A. M. 0.571
4-22 A.M. | 0.571
7 4-22 A.M. | 0.571
8 4-22 A.M. | 0.580
9 4-22 A.M. | 0.571
10 4-22 A.M. | 0.572
12 4-23 A.M. | 0.572
15 4-25 P.M. | 0.523
* Only instance of difference in the two observations made in each case; second showed 0.574.
The results shown in Table 5 were obtained in the laboratory of the writer who can
vouch for the care with which the freezing-point observations were made and who can
obtain no information of any abnormal conditions prevailing in the herd at the time
the samples were taken. Although the low figures seem to be substantiated by their
occurrence in several different cows, at intervals of from one to eighteen days, and in
one case by recurrence in the same cow after an interval of six days, they were not
duplicated or very closely approximated in any other samples from the same cows.
Similarly, the very high figure obtained in the sample from No. 15 was not observed
again in the examination of three other samples. There is no information upon which
these samples can be declared abnormal in the sense of the term herein defined, yet for
the reason that all the figures were obtained from one herd and because they have not
been duplicated by the experience of any other collaborator or satisfactorily substanti-
ated in the laboratory where they were obtained, they are recorded here with the pro-
vision that they require further corroboration and are classed accordingly.
As the data showing the relation between morning and evening milk both of indi-
vidual cows and of herds as regards freezing-point depressions (Table 6), were sub-
mitted chiefly by one collaborator, no adequate comparison upon this point can be made.
The results reported from Connecticut show quite consistently greater depressions
in the case of morning samples, whether from individual cows or herds. The results
reported from the laboratory of Libby, McNeill and Libby do not entirely confirm this
experience, but they are not complete enough to contradict it conclusively.
The extreme figures given in Table 6 show that the differences, without reference to
their magnitude, are in the same general direction as the majority of other differences.
The last four observations in each group of Table 6 are from the Libby, McNeill
and Libby laboratories. In the case of individual cows the data harmonize with
those reported from Connecticut, but in the case of herds they do not. However,
taking the six observations upon herd milk as they stand, the average freezing-point
depression is 0.007°C. greater in the morning milk, an increase well beyond the limit
of experimental error, and one which may be regarded as a real value.
The data showing the variation in freezing-point depressions from day to day, though
not extensive enough to be conclusive, indicate that the variation between the morning
milk and eyening milk is greater than the variation between morning samples or even-
ing samples on successive days.
494 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
HERD AND
TABLE 6.
Variation in freezing-point depressions of morning and evening milk.
NO. OF SAMPLES
cow NO.
A. M. P. M.
Individual Cows
Vequl 5 2,
2 3 Zz
3 2 2
4 2 3
6 2 2
7 1 2
8 1 2
9 1 2
10 1 1
11 1 1
12 1 1
13 1 1
14 1 1
15 1 3
Fl i 1
2, 1 1
3 1 1
4 1 1
5 1 1
6 1 1
7 1 1
8 1 1
9 1 1
10 1 1
11 1 1
Us lel 1 1
Gan. 1 1
A.D. 1 1
O. R. 1 1
Herds
ry, 1 1
F 1 4
Asal! 1 1
Gia 1 1
A.D 1 1
(OR 1 1
* Average.
FREEZING POINT*
A. M.
—0°C.
0.563
0.553
0.560
0.561
0.571
0.571
0.580
0.571
0.572
0.562
0.572
0.540
0.549
0.561
0.542
0.542
0.551
0.543
0.543
0.546
0.552
0.549
0.542
0.547
0.542
0.560
0.549
0.550
0.540
0.553
0.560
0.549
0.553
0.540
0.533
TABLE 7.
FREEZING POINT*
P. M.
—o°c.
0.539
0.549
0.548
0.546
0.539
0.550
0.547
0.548
0.542
0.543
0.551
0.542
0.538
0.538
0.541
0.544
0.533
0.530
0.541
0.542
0.542
0.536
0.534
0.543
0.535
0.546
0.541
0.548
0.540
0.540
0.539
0.541
0.553
0.540
0.533
A. M. FREEZING
POINT
LOWER (+) OR
HIGHER (—) THAN
P.M.
Variation in freezing-point depressions observed in milk from the same individual cow or
the same herd on different days.
FREEZING-POINT VARIATION
HERD AND
cow NO.
UAOamANIorwnre
_
rj
J
NO. OF SAMPLES
A. M. P. M.
Fe WNNNNWNNhd
Individual Cows
EXTREME RANGE
setae eine
i Cee ine otitis
1922] BAILEY: CRYOSCOPY OF MILK 495
TABLE 8.
Range in freezing-point depressions for normal milk.
SPECIFIC GRAVITY | FAT bers ead pg cea
Individual Cows.
Minnesota Dairy and Food Department—1919-1920 (60 samples).
per cent per cent -0°C.
NEST These Sap oiigeaod 1.0350 7.30 10.15 0.562
Minimum.............. 1.0262 2.20 CESYi 0.534
JAvverage Sst... ster: 1.0319 3.94 8.90 0.547
—1921 (17 samples).
LW Ewa 11 ee oe 1.0330 4.9 9.25 0.560
OV ETAT Trea ee eee 1.0281 2.4 8.02 0.540
PAV ETARE ete: tae 5 1.0311 3.4 8.67 0.547
I
Libby, McNeill & Libby—1921 (27 samples).
Maxnmum) 29875 220 1.0380 6.3 10.26 0.563
Minit espe 8) 2085. sist: 1.0256 0.9 7.20 0.532
AV ETARC ch 5 cjeiecicirs sis 1.0313 3.9 8.62 0.546
Connecticut Agricultural Experiment Station—1921 (75 samples).
Weta: oc). es =. oc: 1.0343 6.8 9.63 0.566*
IETIITO TNS ae ea eeeeriole 1.0271 2.7 8.17 0.530*
Average! . 28. oft 1.0313 4.0 8.64 0.543*
Herds.
Minnesota Dairy and Food Department—1919-1920 (15 samples).
Maximum.............. 1.0330 | 5.50 9.27 0.562
MINA « .. ft- - texan « 1.0305 3.10 8.48 0.545
(AR ERITTo, SRe ee Te 1.0319 4.15 8.95 0.551
Libby, McNeill § Libby—1921 (37 samples).
Waxantum):..:..----. 1. 1.0336 5.4 9.30 0.553
Winimum. 12). 22219 2s!. 2. 1.0285 2.7 7.98 0.530
PAV ELARO 0 Li). Sictaicr.is he 1.0312 3.7 8.45 0.542
Connecticut Agricultural Experiment Station—1921 (9 samples).
Vikcctir ir eee 1.0317 4.1 8.77 0.560
PVESTIINTIN 6, oss. + <2.0y-.06 «40 1.0305 3.3 8.38 0.535
LAIGEET SA a 1.0311 3.6 8.50 0.544
Mexinium:>............ 1.0380 7.3 10.26 0.566
Mirtinaum!).)- 00) sense oe 1.0256 0.9 7.20 0.530
LO eee 1.0315 3.8 8.71 0.545
DIARIO ef. 1.0336 3:0, 9.30 0.562
Unt We eee 1.0285 2 7.98 0.530
LS an Ane 1.0313 3.8 8.58 0.544
496 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
The chief purpose of the studies described in this report is to compare the results
obtained by the referee last year with the data obtained from the wider observations
of the several collaborators this year. The combined experience for the two years is
shown in condensed form in Table 8.
From this condensed summary it appears that the tentative limits suggested last
year are not substantially changed by the further observations made in collaborative
study this year. For individual cows the new high of —0.530°C. and low of —0.566°C.
are recorded as compared with —0.534°C. and —0.562°C. reported a year ago. For
herd milk the new high figure of —0.530°C. was found but no new low figure was estab-
lished. The average for individual cows as reported last year (—0.547°C.) remains
practically unchanged (—0.545°C.) while the average for herd milk is raised from
—0.551° to —0.544°C. The minimum depression observed for normal individual
cows is —0.530°C., and the same figure obtains also for herd milk.
As shown in Table 3, long-delayed milking may or may not influence the freezing-
point depression. In one of three cases where milkings were delayed from 914 to 104%
hours, a conspicuous increase in depression occurred, but in the other two the changes
were very slight, one of them being a decreased depression. No evidence is apparent
that milking delayed from 1 to 3 hours produced any effect upon the freezing point.
Moderate exercise, such as a walk of four blocks, was without effect. In cases of
severe exercise, strain or fatigue, such as walks of 5 to 6 miles, the freezing point was
very materially lowered both for individuals and herds, the variations from normal
being from 0.015 to 0.026°C. The comparisons between the normal and abnormal
are true since the observations were made on the evening milk in both cases. In point
of magnitude, certain of the abnormal figures (e. g. —0.571° and —0.578°C.) are at
first glance suggestively coincident with the extremely low depressions observed in a
number of morning samples discussed previously in this report, but they offer no
valid explanation of them, because a delay of 101% hours in milking does not occur
in ordinary practice and because morning milk is drawn after a period of rest.
The observation that cows, to all outward appearances sound and healthy, may
prove to be tubercular as judged by the tuberculin test, is not uncommon. This sug-
gested the desirability of studying the freezing-point depressions of milk obtained from
tubercular reactors and animals otherwise physically abnormal. Over 80% of the
results reported by collaborators (Table 4) were within the limits observed for normal
individuals and herds, but in 5 cases out of 32 unusually high freezing points (—0.520°
to —0.523°C.) were obtained. The evidence in 3 of these 5 cases is, however, some-
what contradictory for the reason that samples drawn from the same cows after an
interval of 2 months gave freezing points within the limits for normal milk. On the
basis of these data, therefore, it would appear that while in many cases tuberculosis and
other pathological conditions may not necessarily be reflected in the freezing-point
depression of the milk, a few exceptionally high freezing points have been observed
and these should be borne in mind when deciding the significance of depressions less
than —0.530°C. in the case of milk from individual cows.
It was not possible to include in this report any adequate review of the literature
dealing with the effect of pathological conditions upon the freezing points of secretions.
Tieken! has shown comparisons between the freezing point of the blood and of various
body fluids for a number of diseases in man. In the several cases of tuberculosis
reported, the freezing-point of the blood remained normal (—0.56°C.), with the other
fluids under observation closely corresponding. When conspicuous departures from
normal were observed in the blood (e.g. in uremic coma) they were in the direction of
increased depressions (—0.58 to —0.68°C.). Marked increase in depression of freezing
point of the blood has been observed by some investigators in carcinoma, excessive
1H. Gideon Wells. Chemical Pathology, 1914, 324.
1922] BAILEY: CRYOSCOPY OF MILK 497
amounts of protein-decomposition products being regarded as the cause, but this
experience has been questioned by others who found no such increase’. Koestler?
investigated the detection of milk altered by secretion disturbances and found that
pathological disturbances increase the serum nitrogen, chlorine and sodium and de-
crease the lactose, potassium and phosphorus. It is stated that the altered milk showed
normal lowering of freezing-point and that this determination is a valuable check in
cases where the general analytical results indicate added water. Further examination
of this and other literature on the subject must be reserved for future study.
CONCLUSIONS.
The complete data for the past two years represent the examination
of 291 samples, distributed as follows:
Normaltindivadtial*Cows!.)), 21 ee ee 179
INonmalsherds: seu: 7) ee ARNEL Sera aie Betts. ey) 61
Diseased or otherwise abnormal individual cows... .. 37
Diseased or otherwise abnormal herds.... ......... 3
Unclassified, requiring further corroboration......... 11
Sota leprae ores joys tie ce Ome emer en rs 291
The results indicate—
(1) That there is an appreciable, and often a conspicuous, difference
in freezing-point depression between morning and evening milk. This
morning-evening variation is greater than that observed between morn-
ing samples or evening samples on successive days.
(2) That the minimum freezing-point depression of —0.530°C. and
maximum of —0.566°C. for milk from normal individual cows and the
minimum of —0.530°C. and maximum of —0.562°C. for the milk from
normal herds is reasonably substantiated by the experience of all col-
laborators.
(3) That from the data here reported the results of moderate exercise
or moderately delayed milkings are not reflected in the freezing-point
depressions of the milk. Long-delayed milkings, 914 to 101% hours,
may or may not be followed by depressions varying from normal. Severe
exercise, strain or fatigue is followed by materially increased depressions.
(4) That the milk from tubercular cows or those otherwise in poor
or abnormal physical condition has generally fallen within the limits for
normal milk as regards freezing points. The few exceptions noted have
been in the direction of decreased depressions.
(5) That extremely low freezing points observed in certain samples
of morning milk suggest a fuller investigation of this point. The study
also of pathological conditions upon the freezing point may well be
continued. The effect of increased acidity upon the freezing-point
depression with a view to corroborating or modifying the correction
factor suggested by Kiester* should be studied
1H. Gideon Wells. Chemical Pathology, 1914, 461.
2 Milt. Lebensm. Hyg., 11: 154.
3 J. Ind. Eng. Chem., 1917, 9: 862.
498 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON THE DETERMINATION OF MOISTURE IN
CHEESE.
By Lioyp C. Mircnett (U. S. Food and Drug Inspection Station,
Minneapolis, Minn.), Associate Referee.
The tentative method for the determination of moisture in cheese!
was studied with a view to its adoption as an official method. It is
essentially the same as the method suggested by G. E. Patrick at the
meeting of the association in 1907.
Preliminary to the work on the tentative method itself, the various
factors which may affect the moisture results were studied. As deduced
from literature and experience these factors? are—
(1) Type of oven used,
(2) Time of drying,
(3) Temperature,
(4) Pressure,
(5) Size of drying dish used,
(6) The presence or absence of porous material, such as asbestos
or sand,
(7) Weight of sample used,
(8) Number of samples dried,
(9) Position of the sample in the oven (with certain types of ovens),
and
(10) Current of air.
One pound of American cheese (Twin Daisy), purchased in the open
market, was used in all the experiments. The samples were prepared
according to the official method and kept about 20 hours in a quart
Mason jar tightly closed before the experiments were started. Each
sample was an arbitrary weight, varying from 5 to 5.5 grams. The
number of samples dried also varied with each experiment. The num-
bers describing the apparatus used were taken from E. & A. Catalog AA
of Chemical and Metallurgical Laboratory Supplies, 1920 Edition. The
temperature was read at 5-minute intervals for the electric oven and at
15-minute intervals for both the vacuum and water-jacketed ovens.
Experiment I.—Jn a high vacuum with a slow current of dry air
(1) Vacuum, FE. & A. 4893.
(2) 3 hours; 1 hour. Total, 4 hours.
(3) 63 to 65°C.; 58 to 67°C.
1 Assoc. Official Agr. Chemists, Methods, 1920, 234.
? Another factor, namely, the relative humidity within the oven during the entire drying period un-
doubtedly plays an important part in the moisture results. This factor was not studied because no
suitable device was available to control the amount of humidity within the oven at the temperature at
which the product was dried.
1922] MITCHELL: DETERMINATION OF MOISTURE IN CHEESE 499
(4) Vacuum, 26 to 27 inches. (76-100 mm. of mercury) Bourdon vacuum gage,
3-inch size.
(5) Aluminum, flat bottom, with fit-over lid; diameter 90 mm., depth 15 mm.,
E. & A. 2604.
(6) None.
(9) Central portion on upper shelf.
Cross Section or Vacuum OvEN
(10) Obtained by bubbling air through sulfuric acid, specific gravity 1.84, at the
rate of 2 bubbles per second.
TABLE 1.
Moisture in cheese. (Experiment I.)
pIsH 1* pIsH 2* TEMPERATURE| DRYING
VARIATION PERIOD
per cent per cent °C: hours
34.10 34.13 63-65 3
00.17 00.18 58-67 1
34.27 34.31 58-67 4.
* Upper shelf—central
Experiment II.—Jn electric oven at atmospheric pressure.
(1) Freas electric, regular (Type R) No. 100, E. & A. 4816.
(2) One period 1 hour; 4 periods 14-hour each; 6 periods 1 hour each. Total,
9 hours.
(3) 90 to 118°C. (See Table 2 for variations during different drying periods.)
(4) Atmospheric.
(5) Aluminum, flat bottom with slip-in lid; diameter 58 mm., depth 17 mm.;
E. & A. 2605.
500 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
(6) Dishes, 1, 4, 7, and 10 contained approximately 1 gram each of cut asbestos;
dishes 2, 5, 8, and 11, none; and dishes 3, 6, 9, and 12 contained approxi-
mately 5 grams each of sea-sand. All dishes were dried in the oven over
night in the same relative positions as during the drying periods. Samples
were placed on porous material, but not mixed with the material.
UPPER SHELF—BACK
(9) Upper shelf, 6 inches above
porcelain plate at bottom of oven.
T—thermometer bulb 5 to 6 inches
above porcelain plate and 614 in-
ches from outer edge of shelf.
A—dishes containing asbestos.
S—dishes containing sand.
|
j
Numbers show relative position of |
the various dishes on shelf. |
|
Lower shelf, 2 inches above por-
celain plate at bottom of oven. A,
S, and numbers, see description
above for upper shelf.
1922] MITCHELL: DETERMINATION OF MOISTURE IN CHEESE 501
TABLE 2.
Moisture in cheese. (Experiment II.)
| | POROUS MATERIAL |
ASBESTOS | SEA-SAND TURE | PERIOD
DISH DISH | DISH DISH DISH DISH | DISH DISH DISH DISH | DISH DISH TION
at | st | ud | a | at | zt | ton | s* | er | or | 124 |
! j
per | per | per per per per per per per | per per °, |
cent — ia cent | cent | cent | cent | cent | cent | cent cent | cent | cent ve | bours
25.10 15.88 17.14 11.49 26.93 22.35 22.49 21.45 28.79 18.69 22.24 17.52 90-109 1
3.70, 4.93) 3.93 4.07 3.76 4.62) 4.39 4.68 2.98 4.57) 4.16 4.13] 97-114 14
1.97, 3.58) 3.33 3.80, 1.96, 2.73 2.75 3.05, 1.32, 3.70 2.76 3.83] 99-109) %
0.49 2.00, 3.41 3.14, 0.59 1.11 1.63 1.36) 0.42, 1.39) 1.56 1.96) 96-113) 14
0.68) 1.31) 0.91 1.36 0.51 0.73 0.69 0.65 0.43) 0.92) 0.68 0.92) 95-112 1%
1.14) 2.22) 1.61 2.63) 0.63) 0.98 1.02, 0.97 0.62) 1.41) 1.11 1.79) 87-114 1
: 0.91 0.38 1.29, 0.78 1.56)100-118 1
0.35 0.21 0.57, 0.39 0.62/103-116 1
0.27, 0.16 0.40 0.28 0.43)103-117 1
0.25 0.09 0.38 0.19 0.37)106-117 1
0.14 0.07 0.21) 0.15 0.23/103-118 1
34.59 59 33.58) 33.22 32. 08 35.38 34.37 34.48 34.08 35.47, 33.53) 34.30 33.36 90-118 9
* Lower shelf—hack.
rs shelf—front.
Pa te shelf—back.
pper shelf—front.
Experiment IIT.—Jn a high vacuum with a slow current of dry air.
(1) See Experiment I (1).
(2) 9 periods, 2 hours each. Total, 18 hours.
(3) 58 to 78°C. (See Table 3 for variations during various drying periods.)
(4) See Experiment I (4).
(5) See Experiment II (5).
(6) Dishes 1, 4, and 7 contained approximately 1 gram each of cut asbestos; dishes
2, 5, and 8, none; and dishes 3, 6, and 9 contained approximately 5 grams
each of sea-sand. All dishes were dried over night in oven. Samples were
placed on porous material, but not mixed with the material.
(10) See Experiment I (10).
TABLE 3.
Moisture in cheese. (Experiment III.)
POROUS MATERIAL
TEMPERA-
TURE DRYING
ASBESTOS SEA-SAND VARIA- PERIOD
TION
pis 2* | pisH 5¢ | p1sn 8t | pisH 1* | pisn 4} | pis 71 | pisH 3*| pisx 6f | pisn 9t
per cent | per cent | per cent | per cent | per cent | per cent | per cent | per cent | per cent CG hours
21.88 | 22.27 | 23.44 | 26.55 | 27.69 | 25.90 | 25.16 | 26.13 | 25.83 | 60-67 2
3.31] 2.82] 2.34] 4.23] 3.74] 4.68] 3.79] 3.44| 3.45] 59-64 2
2.89| 2.62| 2.48| 1.96] 1.70] 2.08| 2.26) 2.02} 2.12] 63-68 2
1.55] 1.37] 1.26] 0.65] 0.58] 0.67} 0.90} 0.81) 0.83) 60-69 2
1.35] 1.30] 1.26] 0.48] 0.43] 0.51) 0.74) 0.65] 0.74] 64-72 2
0.82} 0.92] 0.84] 0.33] 0.29] 0.34] 0.46} 0.45} 0.42| 67-75 2
0.93} 1.10} 0.96} 0.21} 0.16} 0.15] 0.45) 0.38| 0.41] 67-77 2
0.38] 0.43] 0.33} 0.27} 0.36; 0.29] 0.29) 0.27| 0.27| 68-74 2
0.32} 0.37} 0.30] 0.17} 0.16} 0.16} 0.21} 0.20} 0.19] 72-78 2
33.43 | 33.20 | 33.21 | 34.85 | 35.11 | 34.78 34.26 | 34.35 | 34.26 | 59-78 18
+ Ue shelf—back.
pper shel{—central.
} Upper shelf—front.
502 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Experiment IV.—In water-jacketed oven.
(1) Hot water, double wall, E. & A. 4876; size, outside, 10x10x12 inches.
(2) 3 hours; 114 hours. Total, 414 hours.
(3) 93 to 96°C.
(4) Atmospheric.
(5) Platinum, flat bottom, straight sides; diameter 85 mm., depth 20 mm.; with
glass rod about 5 mm. in diameter and slightly longer than diameter of dish.
(6) Dishes 1 and 4 contained approximately 2 grams each of cut asbestos; dishes
2 and 5, none; and dishes 3 and 6 contained approximately 15 grams each of
sea-sand. All dishes were ignited at dull red heat in an electric muflle.
Samples were thoroughly mixed with the porous materials.
TABLE 4.
Moisture in cheese. (Experiment IV.)
POROUS MATERIAL
TEMPERA- DRYING
ASBESTOS SEA-SAND aA Meee Alli poset
DIsH 2* pisa 5t piso 1* pisH 4t DISH 3* pisH 6+
per cent per cent per cent per cent per cent per cent °C. hours
32.01 29.97 34.76 34.42 34.92 34.70 93-96 3
1.59 2.35 0.32 0.26 0.30 0.16 97-98 1%
33.60 32.32 35.08 34.68 35.22 34.86 93-98 41%
* Bottom of oven—central.
+ Upper shelf—central.
Experiment V.—In a high vacuum with a slow current of dry air.
(1) See Experiment I (1).
(2) 1 period 3 hours; 3 periods 114 hours each. Total, 714 hours.
(3) 89 to 98.5°C. (See Table 5 for variations during different drying periods.)
(4) See Experiment I (4).
(5) See Experiment IV (5).
(6) Dishes 1, 3, and 5 contained approximately 2 grams each of finely divided
ignited asbestos; and dishes 2, 4, and 6 contained approximately 15 grams
each of ignited sea-sand. Samples were thoroughly mixed with porous
material.
(10) See Experiment I (10).
TABLE 5.
Moisture in cheese. (Experiment V.)
POROUS MATERIAL
TEMPERATURE| DRYING
ASBESTOS SEA-SAND VARIATIONS PERIOD
pisH 1* pIsH 37 pisu 5t DISH 2* pIsH 4 pisH 6t
per cent per cent per cent per cent per cent per cent Con hours
33.11 33.23 33.06 33.64 33.58 34.24 89-98.5 3
0.20 0.21 0.16 0.15 0.19 0.27 96-98.5 1%
0.13 0.14 0.48 0.24 0.18 0.31 97-98.5 1%
0.12 0.31 0.10 0.12 0.19 0.50 97-98.5 1%
33.56 33.89 33.80 34.15 34.14 35.32 89-98.5 7%
* Upper shelf—back.
+ Upper shelf—central.
+ Upper shelf—front.
1922] MITCHELL: DETERMINATION OF MOISTURE IN CHEESE 503
Experiment VI.—In a high vacuum with a slow current of dry air.
(1) See Experiment I (1).
(2) 1 period 3 hours; 3 periods 114 hours (low temperature); 1 period 2 hours
(high temperature). Total, 914 hours.
(3) 57-72°C., then 95-98°C. (See Table 6 for variations during different drying
periods. )
(4) See Experiment I (4).
(5) See Experiment IV (5).
(6) Dishes 1 and 4 contained none; dishes 2 and 5 contained approximately 2
grams each of finely divided, ignited asbestos; and dishes 3 and 6 contained
approximately 15 grams each of ignited sea-sand. Samples were thoroughly
mixed with the porous material.
(10) See Experiment I (10).
TABLE 6.
Moisture in cheese. (Experiment VI.*)
POROUS MATERIAL
wis TEMPERATURE| DRYING
ASBESTOS SEA-SAND VARIATIONS PERIOD
DISH 1 DISH 4 DISH 2 pIsH 5 DISH 3 DISH 6
per cent per cent per cent per cent per cent per cent °C. hours
28.43 26.60 31.14 31.44 31.91 31.35 57-66 3
1.87 3.72 0.60 0.43 0.45 0.39 62-72 1%
0.51 0.57 0.33 0.47 0.21 0.52 59-65 1%
0.40 0.41 0.28 0.25 0.31 0.18 63-68 1%
0.30 0.31 0.05 0.10 0.077 0.14 60-68 1%
1.55 1.17 0.72 0.84 0.60 0.74 95-98 2
57-72 9
33.06 32.78 | 33.12 33.53 33.41 33.32 95-98 2
* All dishes were placed on upper shelf—central.
+ Increase.
DISCUSSION.
The experiments show that the electric oven used in Experiment II
was unsatisfactory. The temperature was read every 5 minutes and
showed in many instances a variation as high as 10 to 15°C. Take the
eleventh drying period of one hour for example. The temperature
immediately after the 12 samples were placed into the oven and the
door was closed was 96°C.; then at successive 5-minute intervals it
showed 118, 115, 107, 106, 114, 108, 105, 116, 108, 103, 117, and eG:
with no attempt at regulation. This wide variation in temperature
within the oven is more strikingly brought out in a study of the results
showing the loss of moisture during the first drying period of one hour as
reported in Table 2. The thermometer immediately after the 12 sam-
ples were placed in the oven and the door was closed was 90°C.; then at
5-minute intervals it was 98, 90, 96, 102, 105, 100, 103, 104, 105, 102,
103, and 103°C. Dishes 2, 5, 8, and 11, identical in every respect
[Vol. V, No. 4
504 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
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1922| MITCHELL: DETERMINATION OF MOISTURE IN CHEESE 505
except location within the oven, showed a variation of over 14 per cent;
dishes 1, 4, 7, and 10, over 5 per cent; and dishes 3, 6, 9, and 12, over
11 per cent. Both the variations in temperature and the differences in
moisture results indicate that no two places in the oven were heated
alike and that the temperature was fluctuating continuously over a
wide range. A similar condition showing the wide variation of tem-
perature within an electric oven was reported in June, 1921, from the
Bureau of Chemistry, where it was observed that with the thermometer
in the center of the oven (Freas electric) registering 100°C., a thermom-
eter lying on the porcelain plate at the bottom reached a temperature
of 160°C. It is the opinion of your referee that no oven heated with
the heating units within the drying chamber in the manner in which
the Freas electric oven is constructed, without some more suitable
means of circulation, will prove satisfactory for moisture determinations
where known and constant temperatures are required.
The results found in Experiments I, III, VY, and VI indicate that the
temperature was practically uniform throughout the drying chamber of
the vacuum oven, and that a similar statement may be made from
Experiment IV regarding the water-jacketed oven.
The time required to dry the cheese to the point where the loss for
a given drying period is 0.2 per cent. or lower, apparently varies with
every change of condition. In Experiment I this point was reached
within 4 hours, while in Experiment III, where no porous material was
used, it was not reached within 18 hours. It was just barely reached
where sand or asbestos was employed. The only difference between
these two experiments, when the porous material was omitted, was in
the size of dishes used and the number of samples dried. It was noted,
however, that in Experiment I the fat in the cheese did not melt and
run over the bottom of the dishes, whereas it did in Experiment ITI.
In Experiment VI, using practically the same sized dish but drying a
smaller number of samples than in Experiment III, the loss within
two-tenths of one per cent in a given drying period was reached within
9 hours for the samples when porous materials were employed, and
slightly above this amount when they were omitted. The samples lost
from 0.60 to 1.55 per cent more in weight when they were dried for 2
hours longer, raising the temperature from 57-72°C. to the boiling
point of water. This would seem to show that while the samples were
approaching a constant weight at the lower temperature, a greater loss
in weight would be obtained at a higher temperature. In Experiment
V, similar to Experiment VI, except that porous materials were employed
in all 6 dishes instead of 4 with and 2 without and that the temperature
was raised to the boiling point of water instead of around 60 to 70°C.,
the loss within the two-tenths of one per cent was reached within 41%
hours. With further drying the results became erratic, some above and
506 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
some below the two-tenths of one per cent loss. In Experiment IV,
when the water-jacketed oven was used at atmospheric pressure, the
loss in weight was between two- and three-tenths of one per cent within
414 hours for those samples where the porous materials were employed,
but from 1.59 to 2.35 per cent where they were omitted. In Experi-
ment IJ, using the electric oven, the time required for the various dishes
to reach the 0.2 per cent loss varied with the location of the dishes within
the oven.
At the boiling point of water, satisfactory results, apparently, are
obtained by drying either at atmospheric pressure or in a high vacuum.
At a lower temperature, i. e. around 70°C., and with a high vacuum,
Experiment VI seems to indicate that the moisture results would be
too low.
It will be further noted that the moisture results are invariably lower,
not only for the initial drying period but also for the final loss, when
the porous material was omitted, than when either sand or asbestos
was used. Your referee prefers to employ sea-sand rather than asbes-
tos. Sea-sand seems easier to manipulate, while asbestos shows a
slight tendency to absorb moisture when weighing.
CONCLUSIONS.
It may be concluded that cheese may be dried most favorably and
within the shortest time by the use of a large dish, when the sample is
intimately mixed with either sand or asbestos and kept at the tempera-
ture of the boiling point of water at atmospheric pressure or in a high
vacuum. Some analysts may prefer to use 10-15 grams of sea-sand
rather than 2-3 grams of asbestos as given in the method, and to dry at
the temperature of boiling water in a high vacuum rather than at atmos-
pheric pressure.
RECOMMENDATIONS.
It is recommended—
(1) That the tentative method be rewritten so as to include (a) that
either 10-15 grams of sea-sand or 2-3 grams of asbestos be used, and
(b) that the sample be dried either in a vacuum or at atmospheric pres-
sure at the boiling point of water.
(2) That the terms “in a vacuum” or “in vacuo” be specifically
defined. It is suggested that 26-27 inches (75-100 mm. mercury) be
used.
(3) That the present tentative method with the changes recommended
be further studied with a view to its adoption as an official method.
1922] KEISTER: DETERMINATION OF FAT IN MALTED MILK 507
DETERMINATION OF FAT IN MALTED MILK.
By J. T. Kerster (Bureau of Chemisiry, Washington, D. C.), Associate
r Referee.
Owing to the lateness in starting this work, the advance in the date
of the meeting and delay in obtaining the samples, few results were
obtained.
As the opinion had ‘been expressed that one difficulty in determining
accurately the fat in malted milk is due to the lack of uniformity or
unequal distribution of the fat, it was thought desirable to determine
this point, if possible, by noting any differences in results obtained upon
samples made by different methods. Accordingly, one of the manu-
facturers of malted milk furnished two represeutative samples made by
two different processes, known as the “drum” and “‘pan’’ processes.
Two sets only of these samples were sent to collaborators. Results
on one set were received, but the other collaborator could not report in
time for the meeting.
Two samples representing two different makes of malted milk had
been collected previously on the market and sub-divisions had been
submitted to three collaborators outside of Washington and te members
of the Food Control Laboratory, with instructions to make fat determi-
nations by the official Roese-Gottlieb method! and also by the neutral
procedure; i. e., by omitting the use of ammonia in the official method.
The few results returned agree with those obtained by the writer last
year, in that the neutral process extracts the fat more completely. The
difference is usually 0.05 to 0.2 per cent.
It will be noted that a small amount of fat is obtained by a third
extraction when ammonia is used, which rarely occurs otherwise. This
indicates that the ammonia does not facilitate, but rather makes the
complete extraction of fat more difficult.
It is believed that the neutral procedure is a decided improvement
over the regular official method as applied to malted milk, and that the
wide variation in results obtained in the past is due principally to the
treatment of the sample previous to extraction and to small errors
introduced in treating a small sample.
A few experiments were made with one brand of malted milk in which
a modification was introduced during the preparation of the sample.
The results indicate that greater uniformity can be obtained. This
modification will be applied to all the different brands, and the results
will be tabulated and reported to the referee before the next meeting of
the association.
1 Assoc. Official Agr. Chemists, Methods, 1920, 227.
508 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Determination of fat in malted milk.
(All results calculated to water-free basis.)
NEUTRAL ROESE-GOTTLIEB
ANALYST SAMPLE METHOD METHOD
per cent per cent
D. B. Scott, Bureau of Chemistry, Wash- A 9.19 9.04
mgton DUC MwA. MELE ER alae 9.26 8.93
Je ToKeeisten es. ni va aceite arate ene Beever A 8.93 8.59
9.05 8.84
8.99
DSBS Scotts. stx.c on erie one ees B 9.28 9.09
9.26 9.04
TAT MRGISter Ay LN PRN, B 9.14 9.06
9.07 “9.09
9.14 9.07
L. W. Ferris, Bureau of Chemistry, Wash- Cc 9.35 ~ 9.13
angton, D.C oss sais ses sete Sree aro 9.46 9.16
9.47
Mr. Nason, Borden Condensed Milk Co., c, 9.59 9.32
ING We KOE ING Mcticn soe aciny phe marecaeiocs 9.72 9.35
Vid GCOIS COE Ss fe cei s ctsrat esieye ces sie opo vey ai Cc 9.45 9.15
9.49 9.33
9.64 9.27
LF WEth errisvis is cont race ets date sere era D 9.24 9.27
9.17 9.23
14 BARRIS 10) + ER a a a ee SR A 9.35 9.14
9.24 9.03
JT itKeisteniy,.. oo. w. BE RA re B 9.45 9.01
9.25 9.05
9.31 9.27
It is recommended that a study of the neutral method for fat in
malted milk be continued for another year with the view of recommend-
ing to the association some method for adoption.
This method is as follows:
Weigh accurately about 1 gram of the well-mixed sample into a small-lipped beaker,
add 3 cc. of warm distilled water, stir with a glass rod until all lumps disappear and
transfer to a Rohrig tube or similar apparatus. Rinse out beaker with 7 cc. more of
water and transfer to the tube. Add 10 ce. of 95% alcohol and shake; then add 25 cc.
1922} HOLM: THE MOISTURE CONTENT OF DRIED MILK 509
of ethyl ether and shake for at least 1 minute and follow with 25 cc. of petroleum ether,
boiling point below 65°C., and shake thoroughly. Let settle until clear and draw off
through a small filter paper into a weighed flask. Repeat the extraction, using the
same amount of ethers and draw off into the same flask. Distil or evaporate off the
ethers and dry in the oven at 100°C. to constant weight (1-hour intervals). Make a
third extraction using 15 cc. of each ether, drawing off into a separate flask. In case
an emulsion formation is noticed, add a few additional cc. of alcohol in the third ex-
traction. (Extraction is usually complete after two extractions.)
- After presenting his report, “Determination of Fat in Malted Milk’’,
Keister suggested that the following change be made in the official
method relating to condensed milk (unsweetened)!: Change the sen-
tence, “Dilute 40 grams of the homogenous sample with 60 grams of
water and proceed as directed under 1 to 15, inclusive’, to read as
follows: ‘‘Dilute 40 grams of the homogenous sample with 60 grams of
water and proceed as directed under 1 to 12, inclusive’. He explained
that No. 13 of these methods (the regular Babcock method for fat in
fresh milk) was not applicable to a condensed product.
THE MOISTURE CONTENT OF DRIED MILK.
By Georce E. Horm (Dairy Division, Bureau of Animal Industry,
Washington, D. C.).
In 19172, the Referee on Dairy Products, recommending further study
of methods for the determination of moisture in milk products including
dried milk, showed that the moisture content of samples of malted and
dried milk varied from 2.88 to 7.65 per cent, and that constant weight
could not be obtained by drying upon a water bath, but that two hours’
heating in a vacuum oven at 95°C. is necessary for complete drying of
a sample.
In this paper the writer will endeavor to point out some of the diffi-
culties encountered in handling various milk powders and to show that
consistent results can be obtained only when samples are carefully
guarded against available moisture. :
When samples of milk powder, made by a spray or vacuum process in
which the heat was not sufficiently high to destroy the colloidal proper-
ties, were placed in desiccators over concentrated sulfuric acid at 25°C.
it was found that after 7 to 10 days the moisture content of the samples
became approximately constant, but that they still contained more than
1 per cent of moisture. This shows the great avidity that these pow-
ders have for moisture. When, however, the powder had been sub-
jected to high temperature during its manufacture, its adsorption
1 Assoc. Official Agr. Chemists, Methods, 1920, 231.
*J. Assoc. Official Agr. Chemists, 1920, 4: 201.
510 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
properties were lost to a certain extent, and it could be dried completely
or nearly so over concentrated sulfuric acid.
The following table shows a comparison of the moisture content of
these two types of milk powders, dried to approximately constant
weight over concentrated sulfuric acid.
TABLE 1.
Comparison of moisture content of two types of milk powders.
MOISTURE CONTENT AT CONSTANT
SAMPLE NO. Ne SOE WEIGHT OVER CONCENTRATED
CONTENT SULFURIC ACID
per cent per cent
1 2.39 1.54
2 2.61 ¥21
3f 2.34 0.22
4* 2.18 0.00
* Relatively severe heat treatment was given during manufacture.
It had also been noted repeatedly that when a powder was exposed to
the atmosphere the moisture content would increase rapidly. With
these factors in mind, the following procedure was followed in the
determination of moisture on dried-milk samples:
The milk powder was placed in a tightly sealed Mason jar and exposed to the air
only when necessary to remoye each sample. Weighing bottles with ground glass
covers were used in all determinations. A sample of powdered milk (approximately
2 grams) was transferred from the Mason jar to the weighing bottle, the cover re-
placed to insure against adsorption of moisture from the atmosphere, and the sample
weighed. The cover was removed and the sample placed in a water-jacketed vacuum
oven, operating under partial vacuum (approximately 25 inches). A drying bottle
containing sulfuric acid was attached to the drying chamber through which air was
admitted very slowly, thus permitting a more complete removal of the vapors in the
oven. The sample was kept under the desired conditions until removed and the cover
replaced. After cooling in a desiccator over sulfuric acid for 15 to 20 minutes the
sample was weighed.
TABLE 2.
Moisture content of samples of milk made by the spray process.
DRYING PERIOD
DRYING
Be Re 4 hour 1 hour 2 hours 3 hours 4 hours Naat ee
CC; per cent per cent per cent per cent per cent
50 3.04 Low
80 4.02 3.94 4.02 Constant but not com-
plete.
90 4.34 Almost complete.
100 4.43 4.38 4.38 Complete after 1 hour.
100 4.25 4.38 4.36 Complete after 1 hour.
1922] HOLM: THE MOISTURE CONTENT OF DRIED MILK 511
The results given in Table 2 were obtained with a sample of milk
powder made by the spray process, using varying temperatures and
lengths of time in drying.
At 50°C. the drying was exceedingly slow and incomplete; even at
80°C. the sample did not dry completely nor progressively with in-
creased time of drying. At 90°C. the drying was almost complete in
one hour, but there was no advantage over drying at 100°C., provided
this temperature could be used.
It is inadvisable to use temperatures above 100°C. since it has been
reported by N. Schoorl and S. C. L. Gerritzen' that lactose decomposes
at 103°C. in the presence of phosphates.
Several experiments at 100°C. proved that drying in partial vacuum
for one hour at this temperature was sufficient. As seen in Table 2,
further continued drying causes no loss of weight. Determinations
made by another analyst, following the same directions, resulted in a
moisture content of 4.38 per cent on the same sample, which is in per-
fect agreement with the results shown in this table.
Shipping in paper containers is by no means an absolute safeguard
against changes in the moisture content of samples. Milk powder of
relatively high moisture content which has been sealed in paper cartons
and placed in an atmosphere of relatively high humidity (60 per cent)
will absorb moisture rapidly. Samples of low moisture content under
the same conditions adsorb moisture from atmospheres of relatively
low humidity.
CONCLUSIONS.
The results show that accurate and concordant moisture determina-
tions can be made on dried milk if precautions are taken to guard the
samples from contact with moisture while they are being handled.
To insure absolutely reliable results in control methods or in any
work upon this product, it is necessary to safeguard the products by
shipping them in tightly sealed glass or metal containers, since changes
in the moisture content mean heterogeneous and unreliable results with
regard to other determinations, such as fats, proteins, etc.
1 Pharm. Weckblad, 1921, 58: 370.
512 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON FATS AND OILS.
By G. 8S. Jamieson (Bureau of Chemistry, Washington, D. C.), Referee.
It is recommended—
(1) That final action be taken to make official the Wijs method?!
for the determination of iodine absorption number.
(2) That work be undertaken to obtain experimental data to prove
that in the determination of the iodine absorption of an oil by the official
Hanus procedure, it would be preferable to allow the Hanus solution to
act on the oil for 45 minutes instead of 30 minutes, as stated in the
official method. For some years it has been the practice in the Oil,
Fat and Wax Laboratory, Bureau of Chemistry, to allow the Hanus
solution to react on the oil for 45 minutes with the belief that more
uniform and better results were obtained.
(3) That after suitable investigation a more comprehensive descrip-
tion be prepared in connection with the test for the detection of sesame
oil in the presence of olive oil in order to guide the chemist when testing
olive oils, such as those of Spanish or African origin, which frequently
give pink or even crimson colorations with the official tests. Since the
liquid fatty acids of these oils do not give pink or crimson color when
the official tests are applied, it is recommended that the testing of these
acids be added to the official methods. These important changes
should be incorporated into the present methods as soon as possible
as very large amounts of Spanish olive oil are being imported into this
country.
MODIFIED PROCEDURE FOR THE DETERMINATION OF THE
“TURBIDITY POINT” OF BUTTER FAT.
By Armin SEIDENBERG (Chemical Laboratory, Department of Health,
New York, N. Y.).
The following procedure for the determination of the “turbidity
point” is a modification, in detail only, of that described in the original
paper?. While it is more accurate and convenient, it does not affect the
constants that have been established. Besides the particular “‘tur-
bidity point’? described here, it is possible to determine on the same
sample any number of other “turbidity points” that may be desired by
varying any one or more of a number of factors such as temperature,
amount of dehydrated alcohol (or of 90 or 95 per cent alcohol), etc.
1 Assoc. Official Agr. Chemists, Methods, 1920, 245.
2 J. Ind. Eng. Chem., 1918, 10: 617.
1922] SEIDENBERG: “TURBIDITY POINT”? OF BUTTER FAT 513
Weigh 10 grams of the well-mixed sample into a beaker, dissolve in an ether-alcoho!
solution made up by adding from a double graduated pipet 10 cc. of dehydrated alcohol
(1) to 90 cc. of ethyl ether and shake well. Use several portions of this mixture to
transfer the fat from the beaker into a 200 cc. graduated cylinder 30x3 em. Dilute the
solution to about 96 cc. so that when the tubing and thermometer are immersed it will
reach the 100cc. mark on the cylinder. Through an accurately fitted rubber stopper
pass a thermometer and two pieces of glass tubing with an outside dimension of
approximately 0.5 cm. (One tube should reach to the bottom of the cylinder; the other
to just below the stopper.) Use a thermometer (2) approximately 0.5 cm. in diameter
and so graduated that each degree takes up a space of approximately 0.5 cm. It
should reach to below the 45.cc. mark on the cylinder. Cut two circular pieces,
0.2—0.3 cm. in width, from a narrow bore black rubber tubing and pass over the
thermometer, one just above the 13° mark and the other just below the 12° mark.
Place the thermometer near the side of the cylinder.
Attach the cylinder to a ring stand with the bottom of the cylinder about 30 cm.
above the base of the stand. Place a tall beaker containing water at 30-40°C. upon a
ring loosely attached to the stand so that it can be raised or lowered readily, the weight
of the beaker and water holding the ring in position. Aspirate air (3) through the
solution in the cylinder at a rate (4) such that the volume is reduced from 100 to
60 cc. in about 10 minutes (not more than 12 and not less than 8 minutes). Raise
the beaker when the temperature of the solution reaches 13° so that part of the cylinder
is immersed in the water. Adjust the part of the cylinder immersed by raising or
lowering the beaker to keep the temperature between 12 and 13°C. It is usually
possible, after some trials, to adjust the beaker so as to keep the temperature con-
stant. As a rule turbidity increases gradually. Take the “turbidity point’? where a
black object can not be seen through the solution in reflected light (5).
COMMENTS.
(1) Alcohol must be measured accurately and should be 98-99 per
cent by volume; it should contain about 1.5 per cent water by volume.
(2) If desired, a magnifying glass may be attached by a clamp to the
stand holding the cylinder and arranged so that it bears on the part of
the scale at which the temperature is to be maintained; the rubber
bands will further facilitate in marking this part of the scale.
(3) Apparently no particular advantage was secured in first passing
the air through alcohol.
-
(4) If the rate of suction is varied to any extent the result is affected
to a considerable degree.
(5) In determining the exact point at which the solution may be
considered to have become turbid the view should not be directly toward
a light.
514 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS. [Vol. V, No. 4
REPORT ON BAKING POWDER.
By L. H. Baitey (Bureau of Chemistry, Washington, D. C.), Referee.
The work for 1921, following the recommendations of Committee C
for 1920, included a further study of the Chittick method! for the determi-
nation of lead in baking powder; a study of the details of the electro-
lytic method? (Corper-Bryan) for the determination of lead with special
reference to acidity conditions during electrolysis; a study of the methods
for the determination of the neutralizing strength of baking acids; a
collaborative study of the determination of fluorine in baking powders
and phosphates; and a study of the method for the determination of
carbon dioxide in baking powder by a volumetric method* described by
C. §. Robinson.
Determination of lead by the Gravimetric method.
The samples sent to the collaborators were prepared through the
courtesy of J. R. Chittick, (Jaques Manufacturing Company, Chicago,
Ill.). From analysis of constituents, the baking powder contained 3
parts per million of lead; to this was added 50 parts per million of lead
in the form of sulfate, making the sample contain a total of 53 parts
per million.
The Chittick method, having been recently modified by the author,
was submitted for collaborative study. The method in its modified
form follows:
MODIFIED CHITTICK METHOD.
PREPARATION OF REAGENTS.
Sulfuric acid (1 to 5).—Mix 500 ce. of 95% sulfuric acid, C. P., with 2500 cc. of water,
let stand overnight, and filter.
Acid-alcohol-water mizture-—Mix 80 cc. of 95% sulfuric acid, C. P., with 3 liters of
water. Then add 800 ce. of redistilled 95% alcohol (methyl or ethyl), stir thoroughly,
let stand overnight, and filter.
Glacial acelic acid —Redistil C. P. glacial acetic acid and store in bottles made from
lead-free glass.
Alkaline ammonium acetate solution.—Mix 350 cc. of redistilled glacial acetic acid
with 650 cc. of water; dilute 500 cc. of C. P. ammonium hydroxide (sp. gr. 0.90) with
500 cc. of water; then mix the two solutions. Store in bottles made from lead-free
glass.
Potassium chromate solution.—Dissolve 65 grams of C. P. potassium chromate in
100 cc. of water, heating gently. Allow the solution to come to room temperature
and filter.
DETERMINATION.
Weigh 100 grams of the thoroughly mixed sample and place in a 2 liter lipped beaker
Add, in small portions, 750 cc. of dilute sulfuric acid (1 to 5). When frothing has
1 J. Assoc. Official Agr. Chemists, 1920, 4: 218.
2 Thid., 221. i
3 [bid., 1921, 5: 185; Soil Science, 1920, 10: 41.
1922| BAILEY: REPORT ON BAKING POWDER 515
ceased, mark the volume of the mixture on the side of the beaker. Heat on the hot
plate to boiling and continue boiling for 3-4 minutes; then heat on the steam bath
until the starch is hydrolyzed, which requires 20-30 minutes. The mixture will have
a yellow color. (See Note 1, below.)
Remove and add, while stirring, C. P. calcium sulfate which has been finely powdered
in a mortar and rubbed with water to a thin paste.
Monocalcium phosphate baking powder does not need the addition of
calcium sulfate, since of itself it forms sufficient insoluble residue. To
combination baking powders containing in part monocalcium phosphate,
add 10 grams of calcium sulfate. To all other baking powders, add 15
grams of calcium sulfate.
Cool and make up to the original volume with water. Add while stirring, 1 liter of
filtered 95% alcohol, either ethyl or methyl, cover and let stand overnight.
By means of a siphon which can be controlled by a pinch-cock, transfer the clear
supernatant liquid to a Biichner funnel with 3 layers of filter paper (a suitable size
Biichner fits a 9 cm. filter paper). A paper equivalent to C. S. & S. No. 589 Blue Rib-
bon should be employed, using suction.
To the moist residue remaining in the beaker, add 100 cc. of the acid-alcohol-water
mixture. Stir well and let settle. Pour this liquid on the filter. Repeat this opera-
tion, using a fresh 100 cc. portion of the acid-alcohol-water mixture. Wash the beaker,
residue and filter with 70% alcohol, passing the washings through the filter until the
filtrate is nearly free from acid. Discard the filtrate and washings. Wash the filter-
ing flask. Transfer the residue and the filter to the original beaker. Extract the lead
sulfate from the residue by using 100 cc. portions of alkaline ammonium acetate solu-
tion and by heating to boiling; pass the solution through a new filter using an ordinary
funnel. Five extractions are necessary.
Transfer the filtrate, which will measure about 500 cc., to a lipped beaker (see Note
4). Neutralize the glacial acetic acid, using litmus paper as an indicator; then add
10 cc. of glacial acetic acid in excess. Heat nearly to boiling and add 25 cc. of saturated
potassium chromate solution. Cover and let stand 48 hours at room temperature,
stirring occasionally. Filter through a tared Gooch crucible. Wash well with cold
water and dry at 125°C. for at least 45 minutes. Cool in a desiccator and weigh.
The weight of lead chromate multiplied by the factor 0.641 gives the weight of the
lead.
NOTES.
1. During the hydrolysis of the starch, do not heat the mixture to a brown color, as
this greatly interferes with the filtration.
2. The calcium sulfate is added as a diluent and carrier for the lead sulfate.
3. The alcohol used should be redistilled and kept in glass. Either ethyl or methyl
alcohol is efficient.
4. If desired an aliquot (10 cc.) of the alkaline ammonium acetate solution con-
taining the lead may be used colorimetrically’.
5. A practically complete solution of the calcium sulfate by the alkaline ammonium
acetate solution is advisable for the complete solution of the lead sulfate.
6. The Gooch crucible should be prepared with a good felt of purified asbestos fiber
and dried at 125°C. for at least 45 minutes.
Three collaborators reported analyses of lead by this method as
follows:
1 Assoc. Official Agr. Chemists, Methods, 1920, 285.
516 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLE 1.
Gravimetric delermination of lead in baking powder by the Chittick method.
COLLABORATOR LEAD PRESENT LEAD FOUND
parts per parts per
million million
F. B. Carpenter, Virginia-Carolina Chemical Company, 53 37
Richmond! Vas. 22 eo, JOS HERS Rieke heer e cee are 38
Ruth Buchanan, Bureau of Chemistry, Washington, D. C. 53 46
48
50
J. R. Chittick and G. D. Richards, Jaques Manufacturing 53 52
Company; Ghicago, TU yn. pete. caitte eieie otel -eterele 55
50
The results in Table 1 indicate that this method as modified is capable
of yielding accurate results.
TABLE 2.
Electrolytic determination of lead in baking powder by the Corper-Bryan method.
COLLABORATOR LEAD PRESENT LEAD FOUND
parls per parts per
million million
BB: Garpenter’e2 depen, dak sejetveye cbepsietairiaericiehenes fee per apes 53 34*
38*
57t
627
63T
607
607
E. W. Thornton, R. B. Davis Co., Hoboken, N. J........ 53 19t
Ruth Bucharian wisiec'/<ssovs:0 2s 6.0 00.4 ayerese/0l eho tel eh RIMERIF: AiR 53 20t
G. C. Forrester, State Department of Agriculture, E. Lan-
THY sph! Id hee Rael SR SSeS MEO ee Cekae ya ke oe Bo One 53 51
* Electrolyzed overnight.
+ Electrolyzed 3 days.
t Regular method.
{ One-half neutralized, then other half added.
Determination of lead by the electrolytic method.
Samples for the determination of lead by the electrolytic method were
the same as those used for lead determination by the gravimetric method.
1922| BAILEY: REPORT ON BAKING POWDER 517
It was suggested that the collaborators make one determination as
directed in the published method, and another by dividing the solution
into two equal paris just before neutralizing with ammonia, adding
ammonia to half of the solution until incipient precipitation occurs,
then adding the other half of the solution and electrolyzing.
That the hydrogen ion concentration of the solution to be electrolyzed
may vary widely was shown by Forrester, who reported as follows:
A liter of aqueous lead chloride solution containing 0.135 gram of the dry salt equiva-
lent to 0.1575 gram of lead chromate was prepared. 50 cc. of this solution then con-
tained lead equivalent to 0.0078 gram of lead chromate.
Using 50 cc. of this solution and with varying quantities of concentrated hydrochloric
acid (sp. gr. 1.19) and distilled water to a volume of 400 cc., 8 samples were prepared
and electrolyzed overnight (16 hours) with a current of 0.15 to 0.30 amperes. The
deposit of lead was dissolved in nitric acid and precipitated as lead chromate with the
following results:
TABLE 3.
Lead recovered using varying amounts of acid.
VOLUME OF VOLUME OF |
STANDARD ACID TOTAL VOLUME LEAD CHROMATE THEORY
cc. cc. ce. gram gram
50 0. 400 0.0077 0.00787
50 5. 400 0.0073 0.00787
50 10. 400 0.0081 0.00787
50 10. 400 0.0077 0.00787
50 15. 400 0.0077 0.00787
50 25. 400 0.0075 0.00787
50 50. 400 0.0076 0.00787
50 75. 400 0.0081 0.00787
Based upon these eight determinations, the concentration of acid within limits
encountered in working with samples had no influence outside the limits of experi-
mental error on the quantitative deposition of lead.
Since a quantity of 1920 collaborative samples of baking powder for lead determi-
nation was still on hand (it is assumed that these samples contained 50 parts per mil-
lion of lead), the investigation was extended to ascertain whether any ingredient in a
baking powder would interfere with the foregoing generalization. For this purpose
samples were prepared as directed using 75 cc. of concentrated hydrochloric acid and,
with the different samples, varying amounts of ammonium hydroxide were added to
partially neutralize the acid present. i
The average weight of lead chromate, 0.0082 gram, is equivalent to 0.00525 gram of
lead which, from a 100-gram sample, indicates 52.5 parts of lead per million. There-
fore, it would appear that the Corper-Bryan method without attention to concentra-
tion of acid, other than that it be sufficient to prevent precipitation of salts present,
is quite satisfactory for all practical purposes.
The investigation made by Forrester shows that the hydrogen ion
concentration of the solution may vary widely without affecting the
complete deposition of lead upon the electrodes. It would seem, there-
fore, that other considerations govern the completeness of the deposition
518 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
of the lead, and it is thought that a further study of these control con-
ditions should be made before the method is adopted.
TABLE 4.
Lead recovered using varying amounts of ammonia.
ACID NEUTRALIZED BY
WEIGHT OF SAMPLE ORIGINAL ACID EEG SEAS LEAD CHROMATE
grams ce. cc. gram
100 75 0 0.0084
100 75 8 0.0076
100 75 15 0.0085
100 75 35 0.0084
100* 75 50 0.0041
* A heavy precipitate, due to excess ammonia, interfered and result was not taken into consideration.
Carpenter reports that the period of time stated in the Corper-Bryan
method is insufficient to obtain a complete deposition of the lead. He
found it necessary to electrolyze for 2 or 3 days in order to get all the
lead out of the solution.
While the collaborative results as given in Table 2 do not show close
agreement, some analysts obtained results close to theory, and it is
believed that further study will reveal the exact conditions necessary to
get complete deposition of the lead.
NEUTRALIZING STRENGTH OF BAKING ACIDS.
For the study of the neutralizing strength of baking acids, five methods
were submitted to the collaborators, some of which had to be modified
to meet the requirements of the different acids. Samples of the baking
acids—monocalcium phosphate, sodium aluminium sulfate and a mix-
ture of 58 per cent of monocalcium phosphate and 42 per cent of sodium
aluminium sulfate—were furnished through the courtesy of Thornton.
Directions for determining the neutralizing strength follow:
Method A.
Weigh out 0.8401 gram of phosphate into a 3A casserole, add 25 ce. of water and
stir a moment. Add exactly 90 cc. of 0.1N sodium hydroxide. (In case of S. A. S.
add exactly 110 ce. of 0.1N sodium hydroxide.) Bring to a boil; boil for 1 minute;
add 1 drop of 1% phenolphthalein solution and titrate while still boiling hot with
0.2N hydrochloric acid. The end point is obtained when pink color due to indicator
has all but disappeared and does not return in one minute.
CALCULATION.
90—2> (cc. standard hydrochloric acid used) = neutralizing strength of 100 parts
of phosphate in terms of bicarbonate of soda.
Method B.
Weigh out 0.84 gram of the phosphate into a 250 cc. beaker and add 125 ce. of water
and 10-15 drops of a 1% solution of phenolphthalein indicator. Titrate with 0.5N
1922] BAILEY: REPORT ON BAKING POWDER 519
sodium hydroxide to a faint pink; heat to boiling; boil for 1 minute and continue ti-
trating while hot till a permanent pink is reached. The total reading, multiplied by
5, equals the neutralizing value in terms of parts sodium bicarbonate per 100 parts of
phosphate.
Method C.
Weigh 1 gram of the sample into a 300 cc. flask, add 100 cc. of water and 1.0-1.5 ce.
of a 1% solution of phenolphthalein and shake well. Titrate with N sodium hydroxide,
adding 1 cc. of N sodium hydroxide in excess. Boil 1 minute. Titrate, while hot, to
acid with N sulfuric acid. Titrate finally (hot) to permanent pink. Add together the
amounts of N sodium hydroxide used and from this sum subtract the amount of N
sulfuric acid used. The difference in cc. times the factor 0.084 times 100 equals the
neutralizing value of 100 parts of phosphate in terms of bicarbonate of soda.
Method D.
Weigh 0.840 gram of phosphate into a 3A casserole and add 75 ce. of saturated salt
(NaCl) solution. Titrate after adding a 1% solution of phenolphthalein until faint
pink with 0.5N sodium hydroxide. Then add an excess of 0.5N sodium hydroxide to
bring the total number of cc. up to 20, boil the solution for 2 minutes and allow to
cool. (In case of the S. A. S., a total of 24 cc. of 0.5N sodium hydroxide is used and
for the mixture of phosphate and S. A. S., a total of 18 cc.) Add 80 cc. of 0.2N hydro-
chloric acid. (For S. A. S., add 10 ce. of 0.2N hydrochloric acid and for mixture of
S. A. S. and phosphate, add 7 ce. of 0.2N hydrochloric acid.) Titrate the solution
with 0.5N sodium hydroxide.
CALCULATION.
The cc. of 0.1N sodium hydroxide (first titration) equals the “‘cold test’? or parts
of bicarbonate per hundred parts of phosphate in the cold. The cc. of 0.1N sodium
hydroxide (total used)—the cc. of 0.1N hydrochloric acid=the “total strength” or
parts of bicarbonate per hundred parts of phosphate.
Method E.
Weigh 0.84 gram of phosphate and 1 gram of starch in a No. 4 casserole. Add 45 cc.
of 0.2N sodium hydroxide and stir well. (In case of the S. A. S. add 50 cc. of 0.2N
sodium hydroxide.) Add 100 ce. of neutral sodium sulfate (250 grams of crystallized
sodium sulfate per liter) and 1 drop of 1% solution of phenolphthalein. Heat to a
brisk boil. Titrate while hot with 0.2N hydrochloric acid till pink color disappears
and does not return on standing 1 minute.
CALCULATION.
(45 —number of cc. of hydrochloric acid used) X 2 = neutralizing value of 100 parts
of phosphate in terms of bicarbonate of soda. In order to be-sure of neutrality of the
sodium sulfate solution and starch, it is best to run a blank, using 1 gram of starch and
100 ce. of neutral sodium sulfate solution.
The collaborative results on the neutralizing values indicate that any
of the five methods outlined may be used successfully in the case of
sodium aluminium sulfate. The results on the combination of sodium
sulfate and monocalcium phosphate are somewhat lower than those on
the monocalcium phosphate alone. Methods A and € appear to be the
most satisfactory. The principal difficulty with these methods is in
getting a definite end point when phenolphthalein is used as the indi-
520 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TABLie 5.
Collaborative resulis on neutralizing values.
COLLABORATOR METHOD PHOSPHATE | PHOSPHATE AND 8: Ai 8,
8. A. 8.
ESBS Carpenterl tee cate see A 76 75 103
B 79 73 98
(E; 88 74 103
D 85 82 105
E 83 78 102
A. H. Fiske, Rumford Chemical A 82 80 101
Works, Providence, R. I......... B 75 70 100
C 74 74 100
D 94 84 100
E 86 81 105
L. D. Mathias, Victor Chemical A 82 Ay Ask
Works, ‘Chicago, ML. ©. 30% 553245. B 77 70 100
(6; 79 Be #43
D a
E 91
EL AWiepAhOrntons. meee Claas sreeate A 79 77 100
B 75 70 100
Cc (03) 71 100
D 81 78 101
E 83 82 96
W. E. Stokes, Royal Baking Powder A 90
GomNews ork: NepYescs ae B 72
0} 70
D 85
E 81
Axel Malmstrom, Wilckes-Martin- A si 80 103
Wilckes Co., Camden, N. J....... B 76 75 100
Cc 76 74 103
D 88 80 103
E 84 76 105
R. S. Dixon, Provident Chemical A 79 78 104
Works;St. Louis; Mos... ....... B 76 72 103
Cc 71 qi 100
D 85 83 102
E 81 79 101
Dorothy Gaylord, Larkin Co., Buf- A 77 77 100
Lalo, INGEN ES er ote wee een B 76 71 101
Cc 70 70 101
D 90 83 104
E 87 80 105
Ruth Buchanan: see see. vee ester A 79 79 101
B 72 70 95
( 73 71 101
dD 84 83 98
E 83 81 101
* 58% of monocalcium phosphate and 42% of sodium aluminium sulfate.
1922] BAILEY: REPORT ON BAKING POWDER 521
cator. It has been suggested that experiments be made using other
indicators or a combination of indicators in order to secure a more
definite end point and thus reduce, to some extent, variation in results
due to the personal element.
CARBON DIOXIDE IN BAKING POWDER.
(The Robinson Method.)
Since presenting his paper, “Determination of Total Carbon Dioxide
in Baking Powder’, C. S. Robinson has worked out a method of determi-
ning also the residual carbon dioxide by using the same volumetric
apparatus. This apparatus is a modification of the Van Slyke carbon
dioxide apparatus. By its use one can read directly the volume of gas
liberated from a sample of baking powder. Only a limited number of
laboratories are supplied with this apparatus and hence only a few
collaborators could be secured. The results obtained compare favorably
with those obtained by the official Knorr method.
TABLE 6.
Comparative results on the determination of carbon dioxide.
TOTAL CARBON DIOXIDE RESIDUAL CARBON DIOXIDE
COLLABORATOR ——————™
Robinson method Knorr method Robinson method Knorr method
per cent per cent per cent per cent
C.S. Robinson... .. . 16.69 16.67 1.31 1.39
G. C. Forrester... .. . 16.21 aR TY. 0.67 Ra
Ruth Buchanan.... . 16.30 mis - see 1.03
D. B. Scott, Bureau
ofChemistry, Wash-
ington, D. C....... wee 15.92 Ay: 0.82
RECOMMENDATIONS.
It is recommended—
(1) That the modified Chittick method be adopted as a tentative
method. ;
(2) That a further study of the control conditions for the complete-
ness of the deposition of the lead be made before the method is adopted.
(3) That the use of different indicators or a combination of indica-
tors be studied in connection with the determination of the neutralizing
strength of phosphate used in the manufacture of baking powder.
(4) That further study be given to the determination of fluorine in
baking powder.
(5) That a further study be made of the volumetric methods of
determining carbon dioxide in baking powder.
A paper, entitled “The Determination of Carbon Dioxide in Baking
Powder’’!, was submitted by C. S. Robinson and Selma L. Bandemer.
1 J. Ind. Eng. Chem., 1922, 14: 119.
522 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON FLUORIDES IN BAKING POWDER.
By James K. Morton (Bureau of Chemistry, Washington, D. C.),
Associate Referee.
In making a large number of fluorine determinations on rat samples
by the Wagner-Ross! method, it became necessary to check this method.
Carefully selected samples of fluorspar, sodium fluoride (Kahlbaum)
and sodium fluosilicate were used, and about forty analyses were made.
It was found impossible to secure consistent results. The recovery of
fluorine varied from 60 to 95 per cent, the average being about 80 per
cent. This discrepancy was unexplainable, and no data have since
been found that would substantiate the results given by the authors in
their original paper.
A number of modifications of the apparatus and of manipulation were
tried. Air was substituted for carbon dioxide gas and the style of the
digestion flask modified without changing the result in any material
way.
Although the time was too short to send samples for collaborative
work, a number of analyses of baking powders were made.
The determination of fluorine by this method presents a number of
difficulties. In preparing the sample for analysis it is very important
that the organic matter be driven off; at the same time it must not be
heated high enough to volatilize any fluorine present. The presence
of carbon in the digestion flask gives rise to sulfur dioxide. In passing
through the system this gas is not wholly retained by the chromic acid
solution, but it passes into the absorption tube to form a little sulfuric
acid, which is not removed by boiling and which gives high results.
The presence of sulfuric acid must be tested for with barium chloride,
and if any is found it must be carefully estimated by comparison with
known standards and proper allowance made.
The qualitative test for fluorine is extremely sensitive. Its presence
in the digestion flask is indicated by a characteristic scum which forms
on the surface of the sulfuric acid when the flask is slightly heated.
An experienced observer can detect as low as 0.005 per cent of fluorine.
If any silicon fluoride comes over into the absorption tube, 0.005 per
cent can be easily detected by the deposit of silicic acid on the delivery
tube at the point of contact of the gas with water.
The results found by analyzing five samples of baking powder are
given in the following table:
1 J. Ind. Eng. Chem., 1917, 9: 1116.
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524 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
From the table it can readily be seen that when the sample contains
a very low percentage of fluorine the results of the determination are
good. By using a slight modification the recovery of fluorine approxi-
mates 100 per cent. The loss of fluorine is traced to the volatilization
of hydrofluoric acid which passes over into the traps containing sulfuric
acid before it can react with the silica in the digestion flask. A slight
modification in the procedure made it possible to retain the hydro-
fluoric acid in the digestion flask in order that it might react more com-
pletely with the silica present to form silicon fluoride. This gave a
more complete recovery of fluorine and more consistent results.
The following modification of the Wagner-Ross method for the de-
termination of fluorine in baking powder is proposed:
Weigh 20 grams of baking powder in an evaporating dish 1014 cm. in diameter, add
sufficient water to make a fairly thick paste and place on the steam bath until most of
the water has been driven off. Dry at 110°C. for 1 hour. Place in a muffle furnace
and heat slowly with the furnace door open until the material has charred. Close the
door of the furnace and heat to a very low red heat, not over 500°C., until most of the
carbon has been burned off, leaving a grayish white ash. Allow it to cool. Powder
the material and add just enough water to moisten the ash, reignite and repeat this
operation until an ash free of carbon is obtained.
Cool in a desiccator. Place the ash, together with 5 grams of silica (i. e. quartz
flour) and 5 grams of anhydrous copper sulfate in a digestion flask (Pyrex) of 120 ce.
capacity, having a single trap and reflux tube at the outlet, and thoroughly mix the
contents of the flask.
Connect the flask in its position in the train. Force 50 cc. of 98.5 per cent sulfuric
acid over into the digestion flask from a 50 cc. Erlenmeyer connected just behind the
digestion flask, in the train. Allow a portion of the acid to run into the trap by slightly
tilting it. Pass air, thoroughly dried over sulfuric acid, through the train very slowly,
not over 1 bubble per second. Allow the flask, without shaking, to remain in the
cold for not less than 14 hour. Apply heat very slowly, bringing the acid to boiling in
about 1 hour, and boil freely for 10 minutes. Remove the flame and continue to pass
air through the system for 14 hour longer. Increase the rate of flow of the air to about
3 bubbles per second. Proceed as in the original method.
RECOMMENDATIONS.
It is recommended—
(1) That the Wagner-Ross method with modifications be submitted
for further study during the coming year.
(2) That the Wagner-Ross method with modifications be continued
as a tentative method.
The meeting adjourned at 5 p. m. for the day.
FIRST DAY.
MONDAY—AFTERNOON SESSION.—Continued.
DRUG SECTION.
REPORT ON DRUGS.
By Grorce W. Hoover (U. 8. Food and Drug Inspection Station,
Transportation Building, Chicago, IIl.), Referee.
In accordance with the action of the association last year, your referee
appointed a number of associate referees to develop or select suitable
methods for the analysis of important drugs. Collaborative work was
conducted, and some preliminary reports on methods were made by
the associate referees. It is believed that the association should con-
tinue the work on drugs under the same general plan as long as it is
considered that satisfactory progress is being made.
A number of other subjects should receive attention as soon as pos-
sible. The associate referees should, if possible, secure the services of
men who are familiar with the specific subject assigned and who will
take special interest in the work. This is difficult oftentimes owing to
lack of interest or time. A large number of analysts are not necessary;
in fact, a few collaborators giving serious attention to a specific subject
are more to be desired. Another point to be considered is the impor-
tance of proper selection of subjects for study. Often, after considerable
effort, it has been found that work for which there is much need has
been neglected for that of minor importance. Suggestions of the
associate referees and collaborators should serve as guides in determi-
ning the subjects upon which it is most desirable to conduct work and
the general manner of procedure. The associate referees and col-
laborators are to be congratulated on the quality and unusual amount
of work that has been done during the past year.
QUALITATIVE AND QUANTITATIVE ANALYSIS OF ARS-
PHENAMINE (SALVARSAN) AND NEOARSPHEN-
AMINE (NEOSALVARSAN)?
By Greorce W. Hoover and Curis K. Grycart (U. S$. Food and Drug
Inspection Station, Transportation Building, Chicago, IIl.).
Arsphenamine and neoarsphenamine are used extensively at the
present time. Although in former years the supply of these products
came from foreign countries, et the present time it is principally of
1 Presented by Mr. Glycart.
525
526 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
domestic origin. However, it is being imported to some extent and no
doubt the importations will increase in the future as business relations
with foreign countries become adjusted. It is fully appreciated that in
the examination of these products it is necessary to take into consider-
ation both the chemical analysis for arsenic content and the biological
examination for toxicity. In this work only the qualitative and quanti-
tative chemical analyses have been considered.
All the collaborators—H. Engelhardt and R. I. Grantham, Sharp
and Dohme, Baltimore, Md.; George W. Raiziss, The Dermatological
Research Laboratories, 1720 Lombard St., Philadelphia, Pa.; and F. W.
Heyl, The Upjohn Co., Kalamazoo, Mich.—have had wide experience
in handling these products.
Investigators of this subject consider the modified Lehmann method!
one of the most suitable for the determination of arsenic. The reasons
given—that its use by different collaborators on the same sample
gives satisfactory results; that it is rapid; and that aside from the col-
laborative work given in this report, it has won the support of the
chemists of the United States Public Health Seryice—entitle this method
to serious consideration. One of the collaborators, however, states that
the gravimetric method that he employs is very satisfactory.
A sufficient number of samples of arsphenamine and neoarsphenamine
manufactured from the same batches were secured to supply the col-
laborators with samples of uniform composition. The following direc-
tions were submitted for conducting the work:
Qualitative Tests for Arsphenamine (Salvarsan).
3 — diamino 4 — dihydroxy — 1 — arsenobenzene
dihydrochloride corresponding to 31.57% arsenic.
HCINH, . OH.C.;H; . As : As.C.H; . OH . NH2
HCl + 2H,0.
PHYSICAL PROPERTIES.
Arsphenamine is a pale yellow powder, unstable in moist air. It is soluble in water,
1 to 5 parts, methyl alcohol 1 to 3 parts, and only slightly soluble in ether. The aque-
ous solution is greenish yellow, and it reacts strongly acid to litmus. The moisture
content is not more than 7.6% when dried in an atmosphere of hydrogen at 105°C.
CHEMICAL PROPERTIES.
An aqueous solution of arsphenamine (1 to 100) yields no precipitate with dilute
mineral acids, with the exception of sulfuric acid (distinction from neoarsphenamine).
The addition of sodium hydroxide T. S. yields a precipitate which is soluble in excess
of the reagent.
Heated with alkaline solution of potassium permanganate, ammonia is liberated.
Mayer's reagent produces a heavy orange-yellow precipitate.
Ferric chloride solution produces a brownish violet color, turning turbid.
—_—_—_—_—— eS
1 Apoth.-Ztg., 1912, 27: 545.
1922] HOOVER AND GLYCART: ANALYSIS OF ARSPHENAMINE 527
Silver nitrate solution added drop by drop produces a dark red precipitate which changes
to black precipitate.
Reinsch test is positive.
Hydrogen sulfide produces no precipitate even after addition of hydrochloric acid
and warming.
Qualitative Tests for Neoarsphenamine (Neosalvarsan).
Sodium 3 — diamino — 4 — dihydroxy — 1 — arseno-
benzene — methylene — sulfoxylate.
NH..OH .C;H;. As : As . C,H; . OH.NH(CH,0) OSNa.
Mixed with inert inorganic salts.
PHYSICAL PROPERTIES.
Neoarsphenamine is a lemon-yellow powder, unstable in moist air, turning to a reddish
brown color. It is readily soluble in water but only slightly soluble in alcohol or ether.
The aqueous solution is neutral to litmus. On exposure to air the solution rapidly
becomes dark brown.
CHEMICAL PROPERTIES.
A freshly prepared aqueous solution of neoarsphenamine (1 to 100) yields a tardy
precipitate on addition of dilute mineral acids (distinction from arsphenamine).
The addition of 10% sodium hydroxide solution produces no precipitate (distinction
from arsphenamine).
Solution of alkali carbonates produces no precipitate (distinction from arsphen-
amine).
Mayer’s reagent produces no precipitate until the solution is acidified with dilute
hydrochloric acid (distinction from arsphenamine, which yields a precipitate directly).
Ferric chloride solution produces a violet color, turning to dark red.
Silver nitrate solution produces a brown color, quickly forming a black precipitate.
If 5 cc. of dilute hydrochloric acid is added and the mixture heated, the irritating
odor of sulfur dioxide will be evolved (distinction from arsphenamine).
Quantitative Determination of Arsenic in Arsphenamine and Neoarsphenamine.
REAGENTS.
(a) 3% hydrogen peroxide solution.
) Oxalic acid solution—Dissolve 1 gram in water, make to 100 ce.
(c) C. P. potassium iodide.
(d) C. P. potassium permanganate (finely ground).
(e) Potassium permanganate solution—Dissolve 1 gram in water, make to 100 ce.
(f) 0.1N sodium thiosulfate solution.
DETERMINATION.
-
Dissolve 0.2 gram in 5 ce. of 10% sulfuric acid by volume in a 200 cc. Erlenmeyer flask,
fitted with a ground-glass stopper. A blank is conducted, using the reagents under
the same conditions, and the amount of 0.1N sodium thiosulfate consumed is deducted.
Add 1 gram of finely powdered potassium permanganate in small portions, mix thor-
oughly and allow to stand for 10 minutes. Add 10 cc. of concentrated sulfuric acid in
2 cc. portions. Shake thoroughly after each addition. Allow to digest 10 minutes,
rotating the flask frequently during this period. Add 5 to 10 cc. of hydrogen peroxide
solution drop by drop until the brown color disappears. To remove excess of peroxide,
add 25 cc. of water, boil gently for 10 minutes and carefully add a few drops of a 1%
solution of potassium permanganate until the pink color is just permanent. To remove
excess of permanganate, add a drop or two of oxalic acid solution. Dilute with 50 cc.
528 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
of water. When the solution is cool, add 2 grams of potassium iodide, stopper flask
tightly and let stand for 1 hour in a cool place. Titrate the liberated iodine with 0.1N
sodium thiosulfate, omitting the use of starch indicator.
1 ce. of 0.1N sodium thiosulfate is equivalent to 0.00375 gram of arsenic.
The arsenic content of arsphenamine should not be below 30 or above 32%.
The arsenic content of neoarsphenamine should not be below 18 or above 20%.
Determination of Arsenic in Arsphenamine and Neoarsphenamine.
ARSPHENAMINE | ARSPHENAMINE NEOARSPHEN- NEOARSPHEN-
COLLABORATORS SAMPLE A-1 SAMPLE A-1 AMINE AMINE
SAMPLE N-2 SAMPLE N-2
per cent per cent per cent per cent
H. Engelhardt.......... 29.90 30.00* 18.1 18.56*
Re Grantham: sacha 29:50 i. tes Dansiws ee 18:0) 6 P|. susteseee
Bs Wiley lls sid cata cate SO: GOK os \lieet chalets 18.480 \ yo/| ose cme
LOL CASH wail HOP asresttlis 182300 ee ee
GS KeiGlycart..chs. --eek 30.00 30.007 18:53), |) 2 ert
30.07 29.45* 18:48; |) 7 Weer
George W. Raiziss...... 28.08* 30.21} 16.86* 19.097
*After digestion with permanganate, the liberated iodine was discharged by 2% sodium sulfite solution
and then titrated with 0.1N iodine.
ample was dissolved in 5 ce. of 15 % sulfuric acid.
COMMENTS BY COLLABORATORS.
H. Engelhardi—In regard to the volumetric process we believe that the method
has one disadvantage in that a blank test has to be made. In carrying out this test,
we used in one case 0.45 cc. and in another 0.9 cc. of 0.1N thiosulfate solution for titra-
ting the iodine. This difference may be due to the fact that in the latter case the
aqueous acid solution was more concentrated than in the former and that consequently
a more concentrated acid was allowed to act on the potassium iodide, by which more
iodine was liberated. Such discrepancies could probably be obviated by making up
the final liquid to be titrated to a definite volume, say 75 cc., instead of adding 50 cc.
of water to an indefinite volume of liquid. Furthermore, the oxidation might be
carried out with the aid of heat on a steam bath and the reduction of the arsenic acid
to arsenious acid at 40-50°C., by which the time consumed for the latter could be |
reduced from 1 hour to about 10 minutes. Grantham then applied an assay method which
we are using in our laboratory for assaying organically combined arsenic products. This
method differs from the one submitted in that the iodine liberated by the reduction
of the arsenic acid is not titrated directly, but the solution is decolorized by the careful
addition of a 2% solution of sodium sulfite, made slightly alkaline with caustic soda
solution, rendered slightly acid with hydrochloric acid and after the addition of 5 grams |
of sodium bicarbonate is titrated with 0.1N iodine solution. No blank is necessary .
in this test.
In regard to the qualitative tests, it is considered that the reaction with silver
nitrate, both in the case of arsphenamine and of neoarsphenamine, is very indistinct
and should be revised.
George W. Raiziss—The method for the quantitative determination of arsenic, I
find, approaches the Lehmann method. We are using this method for our analysis,
but our procedure differs in the following detail: Take up 200 mgs. of the drug with
5 ce. of 15% sulfuric acid. The gravimetric determination of arsenic in these samples
has not been made because we feel that the modified Lehmann method we are using is
1922| HOOVER AND GLYCART: ANALYSIS OF ARSPHENAMINE 529
giving exactly the same results as the gravimetric determination of arsenic. We ran
comparative analyses of a great number of samples and always found a close agree-
ment.
Raiziss gave attention to the ratio of arsenic to nitrogen, and from his
conclusions it appears that this ratio is important in judging the purity
of the products. Jt would seem advisable, therefore, for the associate
referee to develop methods to determine the ratio of arsenic to nitrogen.
In the future study of this subject it may be desirable to consider the
ratio of other component elements of arsphenamine and neoarsphena-
mine.
RECOMMENDATIONS.
It is recommended—
(1) That the qualitative and quantitative methods submitted here-
with be adopted by the association as tentative methods, and that they
be further studied during the next year with a view to their official
adoption.
(2) That the modification suggested by Engelhardt, which provides
for digestion with potassium permanganate, the addition of potassium
iodide, the discharge of liberated iodine by the use of sodium sulfite
solution and final titration with 0.1N iodine, be studied during the next
year.
(3) That during the next year the associate referee study and devise
methods to determine the ratio of arsenic to nitrogen in arsphenamine
and neoarsphenamine.
As this is the first report made to the association on the subject of
arsphenamine and neoarsphenamine, the following references to some of
the most important articles on the chemistry of these and allied products
are given:
Boon. J. Soc. Chem. Ind., 1914, 33: 1187.
Engelhardt and Winters. J. Am. Pharm. Assoc., 1915, 4: 1468.
Lehmann. Apoth.-Ztg., 1912, 27: 545.
New and Nonofficial Remedies, 1917, 43. i
Puckner and Hilpert. J. Am. Med. Assoc., 1910, 55: 2314.
Raiziss and Falkoy. J. Biol. Chem., 1921, 46: xliv.
Raiziss and Proskouriskoff. Arch. Dermat. and Syph., 1920, 2: 280.
U.S. Public Health Service Reports, 1918, 1003.
530 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON THE DETERMINATION OF ALCOHOL
IN DRUG PRODUCTS.
By A. G. Murray (Bureau of Chemistry, Washington, D. C.),
Associate Referee.
The following method was submitted to several collaborators:
TENTATIVE METHOD FOR THE DETERMINATION OF ALCOHOL
IN DRUG PRODUCTS.
I.—Introduce into a distilling flask of about 200 cc. capacity a measured volume of
the preparation (which has previously been brought to a temperature of 20°C.) not
exceeding 100 cc. and containing not more than 10 cc. of absolute alcohol. Add suf-
ficient water to bring the total volume to 75-100 cc. Connect the flask with a suitable
condenser, to the lower end of which is attached an adapter which extends through the
neck and into the bulb of a 50 cc. graduated flask. Distil at such a rate that there is
no danger of loss of alcohol. (The proper rate of distillation will depend upon many
factors, such as the temperature of the condenser water, the type and size of condenser,
etc.) Continue the distillation until the flask is filled nearly to the mark. If the dis-
tillate consists of a mixture of alcohol and water only, place the flask for half an hour in
a bath maintained at 20°C., fill to the mark with distilled water at 20°C., mix thoroughly
and determine the specific gravity and refractivity at convenient temperatures and
ascertain the proportion of alcohol by volume in the distillate from the reference tables!,
Nos. 7 and 8. From the percentage of alcohol found in the distillate calculate the
percentage in the preparation by multiplying by the proper factor.
COMMENTS.
Instead of the usual form of distilling flask the referee uses an ordinary round-bottom
flask connected to a vertical condenser of the spiral type by means of a spray trap. Is
there any advantage?
Can the alcohol from volumes as great as 100 cc. be safely distilled into 50 cc. where
the distillate will contain as much as 20% alcohol by volume? Can any higher con-
centration be safely permitted? Would the addition of salt or sodium sulfate to the
contents of the distilling flask to raise the boiling point be of any advantage?
Is it necessary or desirable to have 1 or 2 cc. of water in the receiving flask to dilute
the first runnings and prevent loss by evaporation?
Is it necessary or desirable to immerse the receiving flask in a cooling bath? .
Il.—If frothing due to saponin occurs the glucoside may be hydrolized by adding a
little dilute sulfuric or hydrochloric acid to the contents of the distilling flask and
boiling over a low flame. As the frothing ceases, increase the heat and complete the
distillation as usual.
IfI.—The distilling flask should be so protected that no charring of non-volatile
organic matter occurs. If necessary an oil or glycerine bath should be used to heat
the contents of the distilling flask.
COMMENT.
What, if any, special precautions do you take in cases where preparations contain a
large amount of extractives?
IV.—If the preparation contains glycerine the volume taken for the determination
of alcohol must be such that the residue remaining in the distilling flask at the end of
1 Assoc. Official Agr. Chemists, Methods, 1920, 345.
1922] MURRAY: DETERMINATION OF ALCOHOL IN DRUG PRODUCTS 531
the distillation shall contain not more than 50% of glycerine, or the distillate must be
redistilled. j
V.—If the preparation contains iodine reduce with zinc dust or sodium thiosulfate.
If sodium thiosulfate is used a few drops of sodium hydroxide solution should be added
to prevent the distillation of sulfur.
COMMENT.
Does the necessity for not heating a mixture of alcohol, iodine and alkali, resulting
in the formation of iodoform at the expense of alcohol, need to be specifically mentioned
in this connection?
VI.—If the preparation contains a volatile acid neutralize with sodium hydroxide.
If it contains a volatile base neutralize with dilute sulfuric acid. If it contains both a
volatile acid and a volatile base neutralize first with dilute sulfuric acid and distil about
50 ce.; neutralize the distillate with sodium hydroxide and redistil.
VII.—If the preparation contains acetone, camphor, chloroform, ether, or a volatile
oil, dilute the portion to be distilled, if necessary, so that the alcohol content is not
more than 25% by volume; saturate with common salt and shake in a separator with
about 15 cc. of petroleum ether. After the liquids have completely separated draw
off the lower alcoholic salt solution into a second separator and repeat the extraction
with about 15 cc. of petroleum ether. Draw off the lower alcoholic salt solution into
the distilling flask. Wash the two portions of petroleum ether successively with 10 cc.
of saturated salt solution and add the aqueous layer to the contents of the distilling
flask. Distil and continue as in Procedure I. If the character of the preparation is
such as to render difficult the shaking out with petroleum ether make a preliminary
distillation as directed, saturate the distillate with salt, shake out with petroleum ether,
and redistil as directed.
COMMENT.
How completely is acetone removed by this process? In view of the permitted use
of alcohol denatured with acetone for the manufacture of preparations for external
use, this detail is likely to be of practical importance.
VIII.—If the preparation contains chloral hydrate add sufficient concentrated
sodium hydroxide solution to render the solution 0.5N alkali. Stopper and allow to
stand 10 minutes. Shake out with petroleum ether and proceed as directed under
Procedure VII.
COMMENT.
The efficacy of this procedure needs experimental verification.
1X.—If it is desired to test the distillate for the presence of methyl alcohol use Deni-
ges’ method, as follows: Dilute with water the volume of thé distillate which contains
about 0.1 cc. of alcohol to about 4 cc., add 1 cc. of 5% potassium permanganate solution
and 0.2 cc. of concentrated sulfuric acid. After 3 minutes add a few drops of a cold
saturated solution of oxalic acid. When the liquid has become colorless or pale yellow
add 1 cc. of concentrated sulfuric acid, mix and cool somewhat. To the colorless
liquid add 5 ce. of Schiff’s reagent (prepared by adding 100 ce. of a 0.01% solution of
magenta to 2 cc. of a saturated solution of hydrogen sodium sulfite and after 5 minutes
adding 2 cc. of concentrated hydrochloric acid). The appearance of a violet color
after some minutes indicates the presence of methyl alcohol.
COMMENT.
The author claims that the method is capable of detecting 1 part of methyl alcohol
in 1000 parts of ethyl alcohol.
532 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
X.—If the preparation contains methyl alcohol proceed as directed under 17 or 18
of the official methods’, or as follows: ;
From the specific gravity ascertain the content of total alcohol in terms of grams
per 100 ec., using the tables for ethyl alcohol. Denote the result by a.
To a cold mixture of 50 cc. of approximately 0.5N potassium dichromate solution,
25 cc. of water and 50 cc. of concentrated sulfuric acid contained in a 250 cc. graduated
flask add an accurately measured aliquot of the distillate (not exceeding 25 cc.) con-
taining not more than 0.2 gram total alcohol. Mix and allow to stand at room tem-
perature for 24 hours. Dilute nearly to the mark with water, cool to room temperature,
make up to volume and mix thoroughly. To 50 cc. of the mixture add 100 cc. of water
and 15 cc. of a 10% solution of potassium iodide. Titrate with 0.1N sodium thio-
sulfate, using starch as an indicator. A blank control is run at the same time omitting
the alcohol. The difference between the amounts of thiosulfate solution used in the
two titrations multiplied by 5 gives the amount corresponding to the alcohol taken.
Calculate the number of cc. of 0.1N thiosulfate corresponding to 100 ce. of the dis-
tillate. Denote the result by b.
Since the bichromate solution oxidizes ethyl alcohol to acetic acid and methyl alco-
hol to carbon dioxide
1 gram of ethyl alcohol is equivalent to 868.8 cc. of 0.1N thiosulfate, and
1 gram of methyl alcohol is equivalent to 1248.5 cc. of 0.1N thiosulfate.
If zc = Number of grams of ethyl alcohol per 100 cc. distillate and y = Number of
grams of methyl alcohol per 100 ce. distillate,
z+y=a
868.8 x + 1248.5 y = b.
From these equations
1248.5a — b
2 = ———
379.7
and
_ b — 868.8 a
x 379.7
If a higher degree of accuracy is necessary correction must be made for the slight
difference in specific gravities of aqueous methyl? and ethy] alcohols.
COMMENT.
Is there any necessity for including the chemical method?
No samples were submitted, each collaborator being left to prepare
his own. Two or three collaborators commented adversely on this
plan. While the associate referee appreciates the advantages of having
a number of analysts report on the results obtained by the same method
on the same sample he feels that there are, on the other hand, advantages
to be gained by having the method tried on a variety of preparations.
Reports were obtained from the following collaborators:
W. H. Blome, Frederick Stearns & Co., Detroit, Mich.
G. DuBois, Monsanto Chemical Works, St. Louis, Mo.
E. O. Eaton, Bureau of Chemistry, San Francisco, Calif.
J. M. Francis, Parke, Davis & Co., Detroit, Mich.
1 Assoc. Official Agr. Chemists, Methods, 1920, 184.
2U.S. Bur. Standards, Cire. 19, 22.
u
1922] MURRAY: DETERMINATION OF ALCOHOL IN DRUG PRODUCTS 533
H. C. Fuller, Institute of Industrial Research, Washington, D. C.
E. H. Grant, Wm. 8. Merrell Co., Cincinnati, Ohio.
R. I. Grantham, Sharp & Dohme, Baltimore, Md.
B. G. Hartmann, Bureau of Chemistry, Chicago, IIl.
L. D. Havenhill and G. N. Watson, University of Kansas, Lawrence,
Kans.
A. B. Lyons, Nelson, Baker & Co., Detroit, Mich.
F. A. Mallett, Standard Chemical Co., Des Moines, Iowa.
J. I. Palmore, Bureau of Chemistry, Washington, D. C.
J. Rosin, Powers-Weightman-Rosengarten Co., Philadelphia, Pa.
B. H. St. John, Wm. R. Warner & Co., New York, N. Y.
A digest of the comments received follows:
Paragraph I, General Procedure.
Blome.—Average of two determinations on 9.29% alcohol gave 9.29% when a spiral
condenser was used, and 9.12% when a straight tube condenser, placed on a slant, was
employed. These results were calculated from specific gravity determinations. De-
termined by the refractometer, the original sample contained 9.36% alcohol, the dis-
tillate obtained with the spiral condenser 9.25% and that with the straight tube con-
denser 9.37%. Alcohol from volumes as great as 100 cc. can safely be distilled into
50 cc. provided the distillate contains not more than 20% alcohol by volume, but
greater concentrations may result in incomplete recovery. Thus when it was attempted
to distil the alcohol from 200 cc. of 9.27% alcohol into 50 cc. the alcohol in the dis-
tillate corresponded to only 8.62% in the original. Placing water in the receiving
flask and adding salt to raise the boiling point are unnecessary. Except in warm
weather a cooling bath for the receiving flask is also unnecessary.
Hartmann.—Type of condenser, rate of distillation and temperature of condenser
water are factors which will determine the maximum percentage of alcohol which may
safely be distilled. Using a long-necked, 500 cc. Kjeldahl flask, a 15-inch Allihn con-
denser, condenser water at 10-12°C., and distilling 50 cc. in 10 to 20 minutes it was
found that the alcohol from 100 cc. of 10% alcohol was all recovered in the first 50 cc.
of distillate; in the case of 15% alcohol the results were doubtful; in the case of 20%
alcohol the results were low. However, complete recovery was obtained by diluting
100 cc. of 20% alcohol to 150 ce. and distilling off 100 cc. in 20 to 25 minutes. Under
these conditions 40% alcohol gave low results. The lost alcohol was not found in the
distilling flask. It either remained in the condenser or was lost by volatilization from
the receiving flask or both. Indications are that it remained in the condenser.
Eaton.—Water-alcohol mixture containing by specific gravity 9.71% alcohol by
volume (by refractometer 9.72%) was distilled into one-half its volume. Alcohol
calculated from specific gravity of the distillate 9.69%. (Calculated from the re-
fractivity 9.71%.) Apparatus: 200 cc. Erlenmeyer flask, spray trap, spiral condenser,
adapter, and burner guard to protect receiving flask. Thinks round-bottom flask
placed with neck inclined might be better.
Francis.—Prefers ordinary round-bottom flask connected by spray trap to vertical
spiral condenser. Alcohol from volumes as great as 100 cc. can be safely distilled into
50 cc. where the distillate contains not more than 20% of alcohol. Thus 20 cc. of
alcohol diluted with 80 cc. of water and distilled into 50 cc. gave a specific gravity of
0.9520 (duplicate 0.9519), while 20 ec. of alcohol diluted with 55 cc. of water and dis-
tilled into 50 cc. gave specific gravity of 0.9520 (duplicate 0.9518). Cooling bath for
the receiving flask is unnecessary if condenser is efficient and condenser water cold.
534 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Palmore.—25 cc. each of water-alcohol mixtures containing 9.84% and 19.65% (by
volume) of alcohol were diluted to 100 cc.; 50 ce. were distilled off. Duplicate experi-
ments gave 9.58% and 9.66%; 19.34% and 19.40%. The addition of sodium chloride
or sodium sulfate to the liquid being distilled is not of any advantage. The use of a
little water in the receiving flask is unnecessary. Immersing the receiving flask in a
cooling bath is unnecessary if the condensing surface is sufficient and the condenser
water is cold.
DuBois.—50 ce. of alcohol (19.73%) diluted to 100 cc. and distilled into 50 cc. gave
19.73% (receiver dry) and 19.68% (receiver containing 2 cc. water).
Rosin.—If only 50 cc. is to be distilled total volume in distilling flask should not
exceed 75 cc. Prefers to start with volume of preparation containing about 20 cc.
alcohol, dilute to about 130 cc. and distil off 100 cc.
Grantham.—Prefers spiral condenser. Spray trap is advantageous. Alcohol from
a volume of 100 cc. all recovered in 50 cc. distillate provided distillate contains no
more than 20% alcohol.
Mallett—Repeated experiments using 14.1% alcohol indicate practically no loss of
alcohol. Use of a little water in the receiving flask and cooling of receiving flask both
advantageous in warm weather but unnecessary at usual temperatures.
Havenhill and Watson.—Usual type of distilling flask objectionable because of con-
densation in neck above outlet. Prefers ordinary round-bottom flask with short
narrow neck. If neck is inclined at an angle of 45° it serves as a spray trap. Prefers
vertical spiral condenser. Has not found it satisfactory to distil 50 cc. from 100 cc.
Prefers to distil 50 cc. from 75 ce. Addition of salt offers no advantage except per-
haps where 100 or 125 cc. samples are to be distilled into 50 cc. No advantage in adding
water to receiving flask but if room temperature is above 20°C. employs a cooling bath.
Grant.—The method is merely a rehash of official methods for alcohol in foods.
Unnecessary verbiage should be eliminated by referring to XV, 41. A 200 ce. flask is
too small if there is any frothing. No advantage in distilling from a volume of 100 ce.
or more into 50 cc. Necessity for finer temperature adjustments and loss of alcohol
overbalance any increased accuracy obtained by the concentration. Water placed in
the receiving flask is of no advantage unless the adapter dips below its surface. Lightly
plugging the mouth of the receiver around the stem of the adapter with cotton to avoid
air currents practically prevents loss of alcohol vapor.
Fuller —No advantage in distilling from 100 cc. into 50 cc. unless alcohol content is
below 5%. Prefers to use 100 cc. flask for measuring the sample and the same flask
as a receiver. Cooling bath for the receiver is desirable.
Lyons.—Prefers to keep percentage of alcohol in the distillate below 15%, regarding
10%, on theoretical grounds, as the optimum. Addition of salt to raise the boiling
point is unnecessary. Slow distillation holds back many impurities, at least in part.
Refrigeration of the receiving flask is unnecessary except in very warm weather. Placing
water in the receiving flask is unnecessary.
Paragraph ITI, Frothing.
Grantham.—The use of tannin in liberal quantities is preferred to the proposed method.
Havenhill and Watson.—Dilute sulfuric acid gives satisfactory results. Tannin
also is usually satisfactory.
St. John.—Prefers to avoid the use of a volatile acid (hydrochloric). Uses sulfuric
or phosphoric in an amount equivalent to 5 cc. concentrated acid.
Blome.—Small quantity of tannin gives satisfactory results.
1 Assoc. Official Agr. Chemists, Methods, 1920, 173.
=
1922] MURRAY: DETERMINATION OF ALCOHOL IN DRUG PRODUCTS 535
Paragraph IIT, Charring Solids.
St. John.—Dilution served to obviate the difficulty. Oil bath unnecessary.
Grantham.—Dilution serves. Oil bath unnecessary.
Havenhill and Watson.—Dilute sufficiently to keep contents of flask entirely fluid.
Grant.—Add more water. Do not let the flame touch the flask above the water
line. Distil slowly.
Fuller —Dilute considerably.
Francis.—Dilute.
Mailett—Dilution and careful heating are sufficient precautions.
Paragraph IV, Glycerine.
St. John.—Directions are strictly correct.
Grantham.—Directions are correct.
Grant.—Fifty per cent glycerine is a little high.
Blome.—Keep glycerine in distilling flask below 50%.
Paragraph V, Iodine.
Blome.—Working with a solution containing 9.29% alcohol identical results were
obtained by the zinc dust and thiosulfate methods, 9.25%. There is no choice between
the methods so far as results are concerned but zinc dust is perhaps a little more expe-
ditious and obviates formation of sulfur.
Hazenhill and Watson.—Zinc dust is satisfactory.
Grantham.—Zinc dust is much preferred to thiosulfate. It avoids danger of forma-
tion of iodoform and of foaming as occurs almost invariably in the presence of alkali.
Paragraph VI, Volatile Acids and Bases.
St. John.—Suggests sulfuric or phosphoric acid for the neutralization of volatile
bases, magnesium oxide for volatile acids.
Grant.—Magnesium oxide is better than sodium hydroxide, but sodium hydroxide is
prescribed in the official method for wine.
Paragraph VII, Volatile Substances.
St. John.—Practically all alcoholic medicinal preparations containing volatile oils
must be distilled before the shaking out with petroleum ether. Extractives prevent
complete salting out of volatile oils; troublesome emulsions are formed in nearly every
ease. Acetone is not completely removed by this process.
Grantham.—The method does not result in complete removal of acetone. It is
doubtful whether the separation of alcohol from acetone by the use of an immiscible
solvent is practicable.
Blome.—The method does not completely remove acetone.
Francis —The method removes only a small part of the acetone and is entirely worth-
less as a means of separating acetone from alcohol. Suggests as a substitute the pre-
cipitation of acetone by means of Deniges’ mercuric sulfate reagent!. By this method
a solution of 28.6% alcohol in water to which 14 volume of acetone was added showed
28.8% and 29.2% alcohol in duplicate determinations. The result is slightly high but
is sufficiently accurate for all practical purposes.
Paragraph VIII, Chloral Hydrate.
St. John—Surprised to see how smoothly the assay of alcohol in the presence of
chloral works out by the proposed method. The point of vital importance is to use
sufficient caustic soda solution to allow a considerable excess.
1 J. pharm. chemie, 1899, 9:7.
536 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
DuBois.—A solution containing 9.73% alcohol and 2.1 grains chloral hydrate per
fluid ounce assayed 9.52% alcohol; one containing 8.18% alcohol and 91 grains chloral
hydrate per fluid ounce assayed 7.57% alcohol.
Grantham.—To 50 cc. of a solution of 23.5% alcohol was added 10 grams of chloral
hydrate and the assay made as directed, except that 25 cc. of petroleum ether was used
instead of 15 cc. The specific gravity of the distillate indicated 22.5% alcohol. The
distillate gave a positive reaction for chloroform. In another determination shaking
out three times instead of twice with petroleum ether the alcohol was completely
recovered and the test for chloroform in the distillate was negative.
Grant.—Chloral hydrate is so seldom used in alcoholic preparations, and it is so easy
to test the distillate for chloral hydrate or chloroform that work on this method would
be a waste of time. Has never met such a combination.
Blome.—9.29% alcohol to which chloral hydrate was added assayed 9.25%.
Paragraph IX, Methyl Alcohol (qualitative.)
Rosin.—Has found the Deniges test for methyl alcohol to be as delicate as the author
claims.
Grantham.—Because of the delicacy of this test would it not be advisable to haye at
least one confirmatory test? Few tests have received as much attention as this one;
at least 50 have been published. The U. S. P. test is not very satisfactory. Uses the
following: Mix 5 cc. of the sample with 5 cc. of water. Distil. To the first 1 ce. of
distillate add 4 cc. of 20% sulfuric acid. Cool and add 1 gram of potassium permanga-
nate. Allow to stand 5 minutes, filter through a small filter paper, and heat the fil-
trate until the pink color disappears. Mix 1 cc. with 5 ce. concentrated sulfuric acid
containing 50 mgs. morphine. A pink color indicates methyl alcohol.
Fuller.—Finds the method a very delicate one.
Blome.—Followed the directions very carefully with a blank for comparison. 10%
ethyl alcohol and 2% methyl alcohol gave a striking reaction almost immediately;
1%, good results in about 5 minutes; 0.59%, good results in 10 minutes; 0.2%, good
results in 1 hour; 0.1%, fair results in 2 hours and good results in 3 hours. Schiff’s
reagent 24 hours old gave better results than the freshly prepared reagent.
St. John.—By the test described has been able to obtain a decidedly positive test for
methyl alcohol in ethyl alcohol which there was no reason to suspect of adulteration
and which by no other test would give even most faintly a positive reaction for methyl
alcohol. Concludes that the test is absolutely worthless in the form given.
Paragraph X, Methyl Alcohol (quantitative).
Grant.—The chemical method suggested is worthless.
Blome.—
USED { FOUND
Ethyl Methyl Ethyl Methyl!
Alcohol Alcohol Alcohol Alcohol
per cent per cent per cent per cent
10 0.1 9.98 0.16
10 0.2 9.55 0.58
10 1.0 8.50 2.40
10 2.0 7.34 4.24
Method gives roughly twice as much methyl alcohol as the mixture contains, and
is accordingly unsatisfactory.
—_
1922] MURRAY: DETERMINATION OF ALCOHOL IN DRUG PRODUCTS 537
The following revision of the method is based on the data and criti-
cisms received:
Introduce into a suitable flask a measured (at 20°C.) volume of the preparation not
exceeding 100 cc. and containing not more than 10 cc. absolute alcohol. Add water,
if necessary, to bring the total volume to 75-100cc. Connect the flask with a suitable
condenser, preferably of the spiral type, to the lower end of which is attached an adapter
which extends through the neck and into the bulb of a graduated 50 ce. flask. Pack a
little cotton loosely in the mouth of the flask around the stem of the adapter to prevent
air currents. Protect the distilling flask so that no charring of non-volatile organic
matter occurs. Distil at a moderate rate, considering the temperature of the condenser
water, type and size of condenser, etc. Continue the distillation until the flask is
filled nearly to the mark. If the distillate consists of a mixture of alcohol and water
only, bring to a temperature of 20°C., fill to the mark with water at 20°C., mix thor-
oughly, and determine the density at 20°C. or the refractivity at a convenient tempera-
ture, and ascertain the proportion of alcohol by volume in the distillate from the
reference tables, 7 and 8. From the percentage of alcohol found in the distillate
calculate the percentage in the preparation by multiplying by the proper factor.
If the preparation contains much solid matter take for distillation such a volume
within the limits prescribed, that the contents of the distilling flask remain entirely
fluid throughout the distillation. If the preparation contains glycerine take a volume
such that the residue in the distilling flask at the end of the distillation shall contain not
more than 50% glycerine; or redistil the distillate.
If the preparation contains iodine reduce with zine dust.
If the preparation contains a volatile acid neutralize with magnesium oxide. If it
contains a volatile base neutralize with dilute sulfuric or phosphoric acid. If it con-
tains both cations of a volatile base and anions of a volatile acid distil first from an
excess of magnesium oxide, then distil the distillate from an excess of sulfuric or phos-
phoric acid, or vice versa.
If the preparation contains camphor, chloroform, ether, or a volatile oil, dilute the
portion to be distilled, if necessary, so that the alcohol content is not more than 25%
by volume, saturate with common salt and shake in a separator with about 15 cc. of
petroleum ether. After the liquids have separated completely draw off the lower
alcoholic salt solution into a second separator and repeat the extraction with about
15 ce. of petroleum ether. Draw off the lower alcoholic salt solution into the distil-
ling flask. Wash the two portions of petroleum ether successively with 10 cc. of satu-
rated salt solution and add the aqueous layer to the contents of the distilling flask.
Distil as above directed. If the character of the preparation is such as to render diffi-
cult or otherwise undesirable the direct shaking out, make a preliminary distillation,
saturate the distillate with salt, shake out with petroleum ether, and proceed as directed.
If the preparation contains acetone add to the portion to be distilled, a sufficient
amount of a solution of 5 grams of mercuric oxide in a mixture of 100 ce. of water and
20 ce. concentrated sulfuric acid to precipitate the acetone. Allow to stand until the
precipitate settles, filter and distil the filtrate as directed.
If the preparation contains chloral add sufficient concentrated solution of sodium
hydroxide to convert the chloral into chloroform and an excess sufficient to render the
solution about 0.5N alkali. Stopper the flask and allow to stand 10 minutes. Shake
out with petroleum ether and proceed as directed. If deemed advisable a preliminary
distillation may be made.
If frothing due to saponin occurs add a few grams of tannin or hydrolize the glucoside
by adding a little dilute sulfuric acid to the contents of the distilling flask and boiling
very gently, finally increasing the heat and completing the distillation as usual.
538 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
If it is desired to test the distillate for the presence of methyl alcohol take the volume
of the distillate which contains about 0.1 cc. of alcohol, dilute with water to about 4 ce.
and add 1 cc. of 5% potassium permanganate solution and 0.2 cc. of concentrated
sulfuric acid. After 3 minutes add a few drops of a cold saturated solution of oxalic
acid. When the liquid has become colorless or pale yellow add 1 cc. of concentrated
sulfuric acid, mix, and cool somewhat. To the colorless liquid add 5 cc. of Schiff’s
reagent (prepared by adding 100 cc. of a 0.01% solution of magenta to 2 cc. of a satu-
rated solution of hydrogen sodium sulfite and after 5 minutes adding 2 cc. of concen-
trated hydrochloric acid). The appearance of a violet color after some minutes indi-
cates the presence of methyl alcohol.
If the preparation contains methyl alcohol proceed as directed under 17 or 18 of
the official methods.
Some of the collaborators commented on the official density tables
for alcohol. These comments, in the opinion of the associate referee,
deserve careful consideration. ;
St. John says that he finds it more convenient to make specific gravity
determinations at room temperature, using the U. S. P. tables! and
correction data.
Fuller dislikes the official table. In his new book? he has used the
U. S. P. table, but states that he is sorry now that he did not use the
table of Bulletin 107°.
Lyons points out that the official tables themselves are inconsistent,
the density table giving values for volume percentages of alcohol at
20°C., and the refractivity table giving the data for volume percentages
of alcohol at a temperature not stated but presumably 15°C. For some
concentrations the difference is not inconsiderable.
Lyons also points out that Table 7 is a density, not an apparent spe-
cific gravity table. He thinks it should be explicitly stated that in using
these tables it is necessary to reduce all weighings to a vacuum basis.
There is no question but that the tables should all be on the same
basis and your associate referee is of the opinion that the density table
might well be replaced with an apparent specific gravity table. It is
realized that in the preparation of apparent specific gravity tables it is
necessary to assume standard conditions of barometric pressure, hu-
midity and density of the weights; but errors due to slight variations
in these factors are negligible for all practical purposes. Unless the
table is replaced as suggested it is highly desirable that formulas for
making the necessary calculations be introduced into the next revision
of the Book of Methods.
RECOMMENDATIONS.
It is recommended—
(1) That the method for alcohol as revised be studied for another
1U.S. Pharmacopeeia, IX, 1916, 108.
* Chemistry and Analysis of Drugs and Medicine, 1920.
*U.S. Bur. Chem. Bull. 107.
1922| MURRAY: DETERMINATION OF CHLOROFORM IN DRUG PRODUCTS 539
year with the purpose of perfecting it and adopting it as a tentative
method.
(2) That the Committee on Revision of the Methods be instructed
to adjust Tables 7 and 8 to the same basis.
(3) That an apparent specific gravity table with temperature cor-
rections be substituted for the present density table for alcohol-water
mixtures; or, if the association prefers to retain the present table, that
explicit directions and formulas for obtaining density from apparent
weights be introduced.
REPORT ON THE DETERMINATION OF CHLOROFORM IN
DRUG PRODUCTS.
By A. G. Murray (Bureau of Chemistry, Washington, D. C.), Associate
Referee.
The following method for the determination of chloroform in drug
products was submitted to collaborators:
PREPARATION OF REAGENT.
Alcoholic sodium hydrozide—Dissolve 30 grams of sodium hydroxide in 30 cc. of
water, cool and add sufficient methyl! alcohol to make the total volume 100 cc. Allow
to stand overnight and decant the supernatant solution. If the solution contains
more than a trace of chloride the amount must be determined and a proper correction
applied in the determination of chloroform.
DETERMINATION.
Introduce about 10 cc. of the alcoholic sodium hydroxide solution into a 100 cc.
glass-stoppered graduated flask. (Use of a funnel will prevent contact of the alkali
with the upper portion of the neck of the flask and subsequent sticking of the stopper.)
Add not more than 5 cc. of the sample accurately measured or weighed, containing
not more than 1 gram and preferably not less than 0.1 gram of chloroform. Stopper
the flask, mix the contents and allow to stand at room temperature overnight. Loosen
the stopper and heat for 10 minutes on the steam bath. Cool, dilute to the mark with
water and mix thoroughly. Estimate chloride in an aliquot of the solution by the
volumetric method?. One cc. of 0.1N silver nitrate is equivalent to 3.98 mg. of
chloroform. .
If the sample contains chloride determine the amount and apply the proper correc-
tion; or eliminate chloride by a preliminary distillation, taking suitable precautions to
prevent loss of chloroform.
A. W. Hanson of the Food and Drug Inspection Station, Chicago,
Ill., reports that duplicate determinations on5 cc. samples of a 5% solution
of chloroform in alcohol gave recoveries of 99.6 and 101.6%. A 10 cc.
sample of the same solution gave a recovery of 99.5%. Omitting the
final heating low results were obiained (90% recovery), but on reducing
1 Assoc. Official Agr. Chemists, Methods, 1920, 19.
540 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
the time of standing to 3 hours and heating for 5 minutes 99.5% re-
covery was obtained on a 5 cc. sample. At Hanson’s suggestion the
time of heating has been increased in the method as described to 10
minutes. As originally sent out the method specified 5 minutes. Han-
son also suggests that the method be verified for aqueous solutions of
chloroform.
W. H. Blome, of Frederick Stearns & Co., Detroit, Mich., used the
method on the determination of chloroform in a sample of Syrup of
White Pine Compound, in the manufacture of which 4.5 minims of
chloroform per fluid ounce are used, all of which does not go into solution.
The method indicated 4.8 minims per fluid ounce. Blome concludes
that the method gives high results. A second determination on a sirup
to which were added 3.25 minims of chloroform per fluid ounce assayed
4.3 minims, approximately 33% too high. This result is puzzling, for
while a low result can be easily explained, there is no apparent ex-
planation for a high result. Blome states, however, that it was difficult
to observe the end point of the titration on account of the dark color
of the solution.
M. E. Strand, of Parke, Davis & Co., reports complete recovery of
chloroform in the case of a solution containing 1 gram per 100 cc., but
a recovery of only 90% in the case of a solution containing 5 grams per
100 cc. By substituting potassium hydroxide for sodium hydroxide and
using 30 ce. instead of 10 cc., he was able to obtain practically complete
recovery of chloroform in solutions of any strength by diluting, if neces-
sary, so that the 5 cc. used contained not more than 0.2 gram of chloro-
form. He states that the potassium hydroxide dissolves completely
and develops less color than the sodium hydroxide solutions. He says
that theoretically potassium hydroxide is a more powerful saponifying
agent than sodium hydroxide.
E. O. Eaton of the Food and Drug Inspection Station, San Francisco,
Calif., reports that a sample of Mallinckrodt U.S. P. chloroform assayed
by the proposed method 97.2%, duplicate 97.5%. Lower results were
obtained if the final heating was omitted. Low results were obtained
if the solutions were allowed to stand only 4 hours instead of overnight.
These results indicate the need for further directions. While two of
the collaborators report satisfactory results two others report quite
unsatisfactory results, one of these finding that the recovery is not com-
plete and the other obtaining results indicating about one-third more
chloroform than is actually present. Further work to determine just what
conditions influence the reaction is necessary. Strand’s suggestion that
potassium hydroxide be substituted for sodium hydroxide should be con-
sidered. A possible explanation of the better results which he obtained
by the modifications suggested is the increased quantity of reagent
used. Sodium and potassium hydroxides are about equally strong
1922] MURRAY: CHLORAL HYDRATE IN DRUG PRODUCTS 541
bases, molecule for molecule. Since potassium hydroxide usually con-
tains considerably more moisture than does sodium hydroxide and since
the molecular weight of potassium hydroxide is 40% greater than that
‘of sodium hydroxide, it is evident that, weight for weight, sodium
hydroxide yields a much stronger solution of alkali than does potassium
hydroxide. The greater solubility of potassium hydroxide may, how-
ever, warrant its substitution for sodium hydroxide.
RECOMMENDATION.
It is recommended that the method for the determination of chloro-
form in drug products as outlined in this report be studied another
year, with special reference to the criticisms that have been offered by
the collaborators.
REPORT ON THE DETERMINATION OF CHLORAL HYDRATE
IN DRUG PRODUCTS.
By A. G. Murray (Bureau of Chemistry, Washington, D. C.),
Associate Referee.
The following method for the determination of chloral hydrate in
drug products was submitted to collaborators:
Proceed as directed for chloroform. (See report on the determination of chloro-
form, page 530). One cc. of 0.1N silver nitrate is equivalent to 5.51 mg. of chloral
hydrate.
If the sample contains chloride the amount must be determined and the proper
correction applied, or a preliminary distillation may be made. For the latter . purpose
a Hortvet tube! may be used. Distil with steam until the distillate amounts to three
times the volume of the sample taken.
In addition collaborators were requested to report on the United
States Pharmacopceia method? for the assay of chloral hydrate.
E. O. Eaton reports that a sample of Mallinckrodt’s U. S. P. chloral
hydrate assayed by the proposed method 98.4%, a duplicate determi-
nation giving the same result. Using 10 cc. of alcobol containing 2
grams of chloral hydrate, complete recovery was not obtained by dis-
tilling with steam until the distillate amounted to 30 cc. A similar
failure resulted when 10 cc. of an aqueous 40% solution was similarly
distilled. The United States Pharmacopceia method gave slightly higher
than 100%. The method is faulty and could not be trusted in the case
of an unknown mixture.
W. H. Blome, on a sample of bromo-chloral compound, containing
120 grains of chloral hydrate per fluid ounce, found, after making cor-
1 Assoc. Official Agr. Chemists, Methods, 1920, 177.
2U.S. Pharmacopeeia, IX, 1916, 108.
542 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
rection for bromide, 130 grains of chloral hydrate per fluid ounce, an
excess of about 8%.
A. W. Hanson worked on an alcoholic solution of chloral hydrate—
5 grams per 100 cc. ‘Triplicate determinations on 5 cc. portions (0.25
gram chloral hydrate) gave 0.248, 0.248, and 0.242 gram. By follow-
ing strictly the United States Pharmacopeceia directions, on 4-gram
samples the recovery was 4.00 and 4.03 grams. Increasing the amount
of alkali used from 30 to 50 cc. 4 grams assayed 102%. By increasing
the volume of alkali to 60 cc. and the time of standing from 2 minutes to
1 hour the recovery indicated was 120%, due to hydrolysis of chloro-
form.
RECOMMENDATION.
The correspondence in connection with this investigation has de-
veloped the fact that the use of chloral hydrate in medicine has almost
reached the vanishing point. It appears undesirable to take up fur-
ther space for a method for which there will probably be so little need.
It is recommended that no further work be done upon this subject.
INVESTIGATION OF ANALYTICAL METHODS FOR THE
ANALYSIS OF SILVER PROTEINATE.
By W. L. Mircuett! (U. S. Food and Drug Inspection Station, New
York, N. Y.), Associate Referee.
In “New and Nonofficial Remedies, 1921’’, several methods are out-
lined for the determination of silver in silver proteinate and organic
silver compounds. Under the preparation “‘Cargentos” the following
method is outlined:
(1) From 0.6 to 1 gram cargentos is weighed into a crucible and ignited gently at
first, afterward with full flame and a Bunsen burner, until the ash is light in color.
The residue is treated with concentrated nitric acid, and, if completely dissolved, the
solution is diluted with 50 cc. water, 2 cc. ferric ammonium sulfate solution added and
directly titrated with 0.1N potassium thiocyanate. If after treating with nitric acid
an insoluble residue of silver chloride remains, it is collected on a filter, washed with
water, dried, ignited and weighed as silver chloride; the silver content of the filtrate is
determined by titration with 0.iN thiocyanate as before, and the silver so found is
added to that obtained in the silver chloride.
Under the preparation ‘“Solargentum-Squibb”, another method is
outlined as follows:
(2) To about 1 gram of powdered solargentum-Squibb, accurately weighed into a
porcelain crucible, add a mixture of 4.5 gram of lead oxide and 0.5 gram of powdered
tartaric acid. Rotate and mix in a crucible. Heat cautiously until thoroughly car-
1 Presented by G. H. Arner
1922] MITCHELL: ANALYTICAL METHODS FOR ANALYSIS OF SILVER 543
bonized and then heat in a blast flame until the lead button formed is about half its
original size. Allow the crucible to cool, then place it in a beaker and dissolve the lead
button containing the silver in dilute nitric acid. Transfer the liquid, with washings,
into an Erlenmeyer flask and titrate the silver nitrate with 0.1N potassium thiocyanate
volumetric solution, using ferric ammonium sulfate as indicator. The silver content
corresponds to not less than 19 per cent and not more than 23 per cent of metallic
silver (each cc. of 0.1N potassium thiocyanate volumetric solution is equivalent to
0.0107 gram silver).
‘A modification of a method outlined under ‘‘Protargentum-Squibb”’
was used except that the use of potassium permanganate was omitted:
(3) To about 1 gram silvol add 20 cc. concentrated sulfuric acid. Heat over a free
flame until solution is practically colorless and about 10 cc. of the solution remain in
the flask. Cool the residue with water and dilute to 300 cc. Add 5 cc. of concentrated
nitric acid and 5 ce. of ferric ammonium sulfate solution T. S. and titrate with 0.1N
potassium thiocyanate.
Nitrogen was determined using the Gunning method!.
The results of analysis are listed in the following table:
SILVER DETERMINATIONS NITROGEN
DETERMINATIONS
Method 1 Method 2 Method 3 Gunning Method
per cent per cent per cent per cent
(Arovrol etry tena ose 18.28 1S oh al a ge 7.44
(Bratcargalie. to tr2ee<ihy« «1 OY A a Pe on Cereal [ omens 13.94
Cs Tn aa ae P| ewes eee | aliens tote, 55
SHVOLP AE, 81, See ee! 19.20 19.67 20.49 11.56
COMMENTS ON METHODS.
Method 1—There is no difficulty in carrying out this method if the product is free
from chlorides. In case chlorides are present it becomes rather difficult to separate
the insoluble silver chloride from the acid-insoluble ash.
Method 2.—The material after fusion is a brown glossy mass which is difficultly
soluble in acid. Here again in case chlorides are present trouble arises in separating
the insoluble silver salt. .
Method 3.—This method is the least difficult to carry out and apparently gives cor-
rect results. Any insoluble silver salts are converted into the soluble silver sulfate.
RECOMMENDATIONS.
It is reeommended—
(1) That as silver proteinate generally contains chlorides in small
amounts, no further work be done on Methods 1 and 2.
(2) That a further collaborative study be made of Method 3.
1 Assoc. Offic. Agr. Chemists, Methods, 1920, 7.
544 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON THE DETERMINATION OF CAMPHOR IN PILLS
AND TABLETS BY THE ALCOHOL DIS-
TILLATION METHOD.
By Gait H. Arner (U. 8. Appraiser’s Stores, New York, N. Y.),
Associate Referee.
No one method of the several proposed for the estimation of camphor
is in general use or gives entirely accurate results. H. C. Fuller’ and
E. K. Nelson? proposed to determine camphor by taking advantage of
the fact that it forms a well-defined oxime. In a letter to the Referee
on Drugs, Nelson states that the oxime method has proved unreliable,
both in cooperative work done in the United States and in work done
in other countries. The determination of camphor by loss due to evap-
oration is uncertain, owing to the possible presence of other volatile
substances.
The polariscopic method seems to be used most widely and to give
the best results. In the method reported by Edwin Dowzard* the
camphor is steam-distilled in a special apparatus, extracted with benzol
and the rotation of the benzol solution taken. Arthur T. Collins‘
states that the determination of camphor in alcohol by the polariscope
gives very accurate results when a control is used.
It is proposed to determine collaboratively the camphor in pills and
tablets by two promising methods. One of these methods is described
in the ninth revision of the United States Pharmacopeeia®, and the
other has been outlined by Nelson®. The latter method involves steam
distillation and the use of chloroform in the steam generator to prevent
blocking in the condenser tube. The camphor is extracted from the
distillate, made up to a definite volume and polarized.
It is necessary to run a control with each determination, using a
sublimed sample of the camphor under examination as different lots of
natural camphor show variations in rotation.
It is proposed to study these two methods collaboratively.
1U.S. Bur. Chem. Cire. 77: 1911.
2U.S. Bur. Chem. Bull. 162: (1912), 208.
3J. Ind. Eng. Chem., 1914, 6: 489.
4 Ibid., 1912, 4: 514.
‘U.S. Pharmacopoeia, EX, 1916, 233.
* Personal communication.
1922] HARRISON: ESTIMATION OF SANTALOL IN SANTAL OIL 545
ESTIMATION OF SANTALOL IN SANTAL OIL BY THE ASSAY
METHOD OF THE UNITED STATES PHARMACOPGIA
AND BY THE DISTILLATION METHOD
By C. W. Harrison (U.S. Food and Drug Inspection Station, Park
Avenue Building, Baltimore, Md.), Associate Referee.
The collaborative work on the United States Pharmacopeeia! and dis-
tillation? methods for the determination of santalol in santal oil, begun
in 1920, was continued. The same general plan of work was followed,
except that the instructions sent to collaborators were more specific, it
having appeared from the previous year’s results that the collaborators
did not entirely understand the procedure in either method.
Four samples were sent out with detailed instructions as follows:
Place about 21 cc. of oil in an acetylization flask with an equal volume of acetic
anhydride and a few grams of fused sodium acetate and boil for about an hour. Trans-
fer contents of flask to a small separatory funnel and wash four times with 20 cc. of
sodium carbonate solution (5 grams in 100 cc.). (Test the final wash solution with
phenolphthalein to be certain that it is alkaline, indicating that all free acid has been
removed. If the wash solution is not alkaline to phenolphthalein, continue washing
with sodium carbonate solution until the washings show an alkaline reaction.)
Transfer the acetylated oil to a 25 cc. cylinder, fill nearly to the surface of the oil
with granular (4-mesh) anhydrous calcium chloride and allow the mixture to stand
overnight. (This is necessary to dry the oil completely.) Pass through a dry filter.
Into a dry, tared, 100 cc. Erlenmeyer flask run about 5 cc. of the dry, filtered, acety-
lated oil and weigh accurately. Then add 50 ce. of approximately 0.5N alco-
holic potash solution. Measure into another flask 50 cc. of the alcoholic potash solu-
tion, using the same pipet, drain the same length of time, and carry through as a blank.
Heat on the steam bath about 30 minutes, using a small funnel as a reflux, cool and
titrate with 0.5N acid and phenolphthalein, titrating the blank at the same time.
Subtract the number of cubic centimeters of 0.5N acid required for the titration of the
sample from the number required by the blank and calculate the percentage of santalol
from the formula:
AX11.11 , A” representing the difference in cc. between the sample and blank,
B—(A X0.021) and “B” the weight of acetylated oil used.
To the flask containing the residue after titration, add 1 or 2 drops of alcoholic potash
to render it faintly alkaline, place on the steam bath and evaporate to a small volume
(about 10 cc.). (This is easily and quickly accomplished by passing a tube attached
to a vacuum into the neck of the flask nearly to the surface of the liquid, thus carrying
off the hydroalcoholic vapors as fast as they form.)
Transfer the residue in the flask, by aid of a small funnel, to the distillation appara-
tus, carefully washing the adhering material from the flask and funnel into the ap-
paratus with 15 to 20 ce. of approximately 5% acid. (Hither hydrochloric or sulfuric
acid is satisfactory, but it is necessary to use the same kind of acid as was used for the
previous titration.) Add also a drop or two of methyl orange TS to be certain of an
excess of mineral acid.
1U_S. Pharmacopeeia, IX, 1916, 296
2 J. Assoc. Official Agr. Chemists, Methods, 1920, 425.
546 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Steam-distil the material and titrate the volatile acids with 0.5N alkali and phenol-
phthalein. Most of the acids come over in the first 250 ce. of distillate, but the dis-
tillation should be continued until 20 cc. of distillate requires only 1 or 2 drops of 0.5N
alkali to neutralize it. Calculate the santalol content from the formula:
Ce. of 0.5N alkali 11.11
Weight of oil—ce. of 0.5N alkali X0.021 _
Results were received from one collaborator only, and these did not
show a satisfactory agreement with the results obtained by the associate
referee, the disagreement being about equally great in the case of both
methods.
The four samples consisted of two pure santal oils, designated as
Nos. 1 and 3, and two compound oils, designated as Nos. 2 and 4, respec-
tively.
Compound No. 2 was prepared by adulterating Santal Oil No. 1 with
12% cocoanut oil and 5% cubeb oil, and Compound No. 4, by adulterating
Santal Oil No. 3 with 18% cocoanut oil and 10% cubeb oil.
The following results, expressed as per cent, were obtained:
Results by the U. S. P. and distillation methods*.
ANALYST SAMPLE 1 SAMPLE 2 SAMPLE 3 SAMPLE 4
B
A. W. Hanson, U. S. Food | 91.4 | 91.2 | 89.3 | 81.2 | 92.3 | 92.3 | 86.8 | 71.9
and Drug Inspection Sta-| 91.5 | 92.0 | 90.3 | 79.4 | 91. 91. ;
tion, Chicago, Ill.
GAWeE Harrusont ee eee 87.0 | 86.4
** A" refers to U.S. P. method; “B” refers to distillation method.
COMMENTS.
This table shows the lack of agreement between the analysts when
reporting results by either method. The inference, therefore, is that
the fault lies in the present procedure of acetylating the oil since this
step is the same in both methods. The acetylization procedure should
be changed so that the results will show invariably a uniform saponi-
fication number.
The distillation method, while not entirely satisfactory, shows the
adulteration much better than the United States Pharmacopoeia method.
This is illustrated by Hanson’s results, about which he makes the com-
ment that the distillation method indicates that Samples 2 and 4 are
adulterated, although they might pass by the United States Pharma-
copoeia method.
Since these two samples were adulterated with 17 and 28 per cent,
respectively, of foreign oils, the weakness of the United States Pharma-
copoeia method, when dealing with adulterated oils, is at once apparent.
1922] CLARKE: REPORT ON TURPENTINE 547
It has been pointed out by E. K. Nelson! that the distillation method
possesses certain advantages over the United States Pharmacopceia
method when working with pure oil, it being his opinion that it would
give more nearly the true percentage of santalol present.
It may be concluded, therefore, that since the distillation method
possesses certain advantages over the United States Pharmacopceia
method and gives more accurate results on both pure and adulterated
oils, it warrants further study. If the procedure of acetylating the oil
can be satisfactorily solved, the method will be suitable for presentation
to the association as a provisional method.
REPORT ON TURPENTINE.
By J. O. Cranks ( U.S. Food and Drug Inspection Station, Savannah,
Ga.), Associate Referee.
The present tentative method for the detection of mineral oils in
turpentine and a method proposed by A. E. Paul? were studied. Poly-
merization is effected in the Paul method with sulfuric acid, followed by
fuming nitric acid. The accuracy of the usual methods for specific
gravity and refractive index was also studied, since these items could
easily be handled on the same samples used for the polymerization work.
Collaborators were requested to make the following determinations
on three samples of turpentine: Specific gravity and refractive index,
using the official methods*; polymerization by the fuming sulfuric acid
method, using the official methods; and polymerization by the sulfuric
nitric acid method, using the Paul method.
The samples were designated as A, B and C. Sample A was an
authentic specimen of pure gum turpentine, redistilled in the labora-
tory. Samples B and C were portions of A, containing, respectively,
5 per cent and 10 per cent of kerosene.
The detailed results obtained by the collaborators on the methods for
mineral oils are given in Table 1.
COMMENTS BY COLLABORATORS.
The following brief of the comments by the collaborators should be
considered in studying the tables:
J. M. Anderson.—The sulfuric-nitric acid method is impracticable, owing to the
amount of time consumed; danger of overheating in adding turpentine distillate, causing
loss of low boiling adulterant; inability to check results on repeated trials; and difficulty
in removing residue (when of a heavy consistency) left in still on first steam distil-
lation.
——
1 J. Assoc. Official Agr. Chen 1921, 5: 169.
2J. Ind. Eng. Chem., 1909, 1: 27.
* Assoc. Official Agr. Ceesatats. Methods, 1920, 306.
[Vol. V, No. 4
548 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
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1922] CLARKE: REPORT ON TURPENTINE 549
W. C. Smith—The accuracy of the two methods is the same. The fuming sulfuric
acid method is preferable because it can be run in a much shorter time and on a smaller
sample.
C. K. Glycart.—The fuming sulfuric acid method appears to give satisfactory results,
but much difficulty was experienced in the preparation of the 38N sulfuric acid reagent.
The sulfuric-nitric method appears to give satisfactory results, but requires much care
in its manipulation. In the examination of an unknown sample, the analyst would
feel more certain of the results than by the more empirical fuming sulfuric acid method.
It would seem that the sulfuric-nitric acid method should be seriously considered as
an alternative.
C. W. Harrison.—Sample A is apparently a pure turpentine, even though it leaves a
residue when treated by the official method equivalent to 1.1% by volume. It seems
that in computing the amount of mineral oil in samples B and C, this figure should be
subtracted from the percentage of residue found. Sample A, when treated by the
sulfuric-nitric acid method, yields no residue, while samples B and C show 2.3 and
5.3% residue, respectively, and apparently there should be no deduction from these
figures, the inference being that they represent the volume percentage of mineral oil
present in the samples as determined by this method.
The refractive indices of the residues obtained by the sulfuric-nitric acid method are
lower than those obtained by the fuming sulfuric acid method, indicating that the
sulfuric-nitric acid method gives a residue containing less of the turpentine polymeriza-
tion products. The residues from Samples B and C obtained by the sulfuric-nitric
acid method, judging by the refractive index, are of a more uniform composition and
nearer the range for gasoline than the results obtained on these samples by the fuming
sulfuric acid method. I am, therefore, inclined to believe that the sulfuric-nitric acid
method gives results which more nearly show the true percentage of mineral oil present.
I rather favor the sulfuric-nitric acid method as it is less trouble and does not require
the standardization of the acid. Pure turpentine does not show an unpolymerized
residue when treated by this method.
Fuming Sulfuric Acid Method.
This method gave concordant results, and, with one exception, the
recovery of the adulterant was remarkably good. With pure gum tur-
pentine a residue of about one per cent is expected. If more than this
is found, the refractive index of the residue should indicate whether or
not a petroleum product is present.
The criticism most frequently offered was the difficulty in preparing
the sulfuric acid reagent. Some work was done on this point by the
writer, and the difficulty disappeared after a little experience. If the
concentrated sulfuric acid used is boiled for several hours, it finally
reaches a concentration of about 97 per cent sulfuric acid, and the
preparation of acid of this strength effects considerable saving in the
quantity of fuming acid required. One of the collaborators stated that
the method of converting the sulfuric acid into ammonium sulfate and
weighing was not so satisfactory as determining the strength by titra-
tion. This has been the experience of the writer. More work can
profitably be done on the preparation of the reagent.
The time of the initial reaction affected the recovery of the mineral
oil. A slow addition of the sample appeared to lower the results; on
550 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
the other hand, when the turpentine was added to the acid too rapidly,
too much heat was developed, with possible loss of a part of the sample.
In studying this point, six duplicate determinations were made with
strict adherence to the method in all respects except that the time
consumed in adding the sample was varied. In all determinations the
acid was cooled to about 5°C. in ice water, the sample added under
accurate time control and the temperature taken at the moment the last
drop of turpentine was added. Sample C, containing 10 per cent of
mineral oil, was used. A study of Table 2 shows that about half a min-
ute should be consumed in adding the sample.
TABLE 2.
Influence of time of addition of samples on results.
TEMPERATURE
TIME a Le RESIDUE
Beginning End
Minutes OF, °c, per cent
0.5 5.0 67 9.2
1.0 5.0 55 8.8
2.0 5.0 39 8.8
3.0 5.0 Ae 8.0
4.0 5.0 23 8.0
5.0 5.0 oo 7.6
Sulfuric-Nitric Acid Method.
The results by this method in general were low. One of the col-
laborators recovered practically all of the adulterant in Samples B and
C. However, the average recovery was not so satisfactory. The
method appears to have some merit and might be useful as an alter-
native.
The first distillation should be continued until 400 cc. of the dis-
tillate are obtained. An experiment by the writer, using Sample C
which contained 10 per cent of kerosene and measuring the oil recovered
in each 50 ce. fractions, gave the following figures:
Om Or
ce. ce.
ist traction. ssf eee nee. 25.0 Sth fraction... sees 8.5
2nd 'fractiony. jesus s -t 24.0 6th) fraction:). .jibiiecsn. cee 3.5
Srdifractioneisc2e)t eh ated 20.0 th) fractions... casjaeice aie 1.5
Athitrachlon cements 15.0 Sthifraction:) =. eee 1.0
Not all of the oil was recovered in the first 100 cc. of the second dis-
tillate. Using Sample A (pure turpentine) 10.0 cc. of oil were recovered
in 400 cc. of the distillate, and when the distillation was continued
2.0 cc. more were recovered in the next 400 cc. With Sample C, con-
taining 10 per cent of kerosene, 11.5 cc. of oil were recovered in the
1922] CLARKE: REPORT ON TURPENTINE 551
first 100 cc. of distillate, giving 4.2 cc. residue after polymerization with
fuming nitric acid. On continued distillation to a total volume of
900 cc. 8.0 cc. more oil were recovered, which gave 2.6 cc. residue on
final polymerization. The second distillation should be continued until
the total distillate measures about 900 cc.
TABLE 3.
Collaborative study of specific gravity and refractive index on turpentine.
SAMPLE A | SAMPLE B | SAMPLE C
|
| |
COLLABORATOR | Refractive Specific i Refractive Specific Refractive Specific
Index Gravity Index Gravity | Index Gravity
| 20°C. 20°/4°C. | 20°C. 20°/4°C. | 20°C. 20°/4°C.
I | |
|
J. M. Anderson. | 1.4712 0.86271 | 1.4703 0.86040 | 1.4683 0.85670
| Yetdeks 0.86278 yw ere eee O'S6036" |) Se: 0.85663
|| |
W. C. Smith. | 1.4720 0.86396 | 1.4708 0.86137 | 1.4692 0.85824
| 4
C. K. Glycart. | 1.4757 0.8639 | 1.4720 0.8597 | 1.4695 0.8571
L. A. Salinger* | 1.4719 0.86410 | 1.4703 0.8603 1.4695 0.8574
1.4720 0.86400 | 1.4704 0.8600 1.4694 0.8575
| |
J. O. Clarke. 1.4724 0.86360 1.4711 0.86063 | 1.4697 | 0.85780
Wea escorenens 0.86369 | ..... 0.86060 poseeee 0.85780
i"
| |
CawWe Harrisons: 9} his: 0:86432) |"... = -: 0.86104 Btiaecas 0.85779
Maximum....... 1.4757 0.86432 i 1.4720 0.86137 i 1.4697 0.85824
Minimum....... | 1.4712 0.86271 | 1.4703 0.85970 | 1.4683 0.85663
*U. S. Food and Drug Inspection Station, Savannah, Ga.
The results of these determinations were surprising. A study of Table
3 shows quite a discrepancy among different operators, although the
duplicate determinations by the same operator check very closely.
Probably the variation in refractive indices is due to inaccurate re-
fractometers rather than to faulty manipulation. The determinations
on specific gravity show a rather wide range, differing materially in the
third place.
RECOMMENDATIONS.
It is recommended—
(1) That the fuming sulfuric acid method be further studied with
552 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
especial attention to the preparation of the reagent and that the follow-
ing form be used:
I. Polymerization—Fuming Sulfuric Acid Method.
REAGENT.
38N sulfuric acid —Mix 140 grams of concentrated sulfuric acid with sufficient liquid,
fuming sulfuric acid (about 100 grams), to obtain an acid slightly stronger than 38N.
Determine the exact strength of this mixture and also of the concentrated acid as fol-
lows: Weigh out 6-8 grams in a bulb, having a capillary tube in the lower end and a
tube with a stop-cock in the upper end, fitted with a platinum wire for suspending on
a balance. (The bulb is filled by the aid of a slight vacuum; the lower end of the cap-
illary is emptied by closing the stop-cock simultaneously with the withdrawal of the
capillary from the acid; and the tip of the bulb is then wiped off first with a wet and
then with a dry piece of cloth.) Run the acid into cold water, make up to volume and
titrate an aliquot of the solution against standard alkali. Calculate the sulfur tri-
oxide content of the acid and add sufficient concentrated sulfuric acid to make it exactly
82.38% of SO;. (The acid must be carefully protected against absorption of water
from the air.)
DETERMINATION.
Place 20 cc. of the 38N sulfuric acid (82.38% SO;) in a graduated narrow-necked
Babcock flask, stopper, place in ice water and cool. Add 5 cc. of the turpentine at
such a rate that it is all added in 30 seconds, meanwhile revolving the flask in the ice
water, so that the sample is mixed with the acid as added. When the mixture no
longer warms on shaking, agitate thoroughly, place in a water bath and heat to 60°—
65°C. for about 10 minutes, keeping the contents of the flask thoroughly mixed by
vigorous shaking 5 or 6 times. Cool to room temperature and fill the flask with con-
centrated sulfuric acid until the unpolymerized oil rises into the graduated neck. Centri-
fuge 4-5 minutes at about 1200 revolutions per minute, or allow to stand for 12 hours.
Read the unpolymerized residue, notice its consistency and color and determine the
refractive index.
(2) That the sulfuric-nitric acid method be further studied using the
following slightly modified form:
II. Polymerization.—Sulfuric-Nitric Acid Method.
REAGENTS.
(a) Concentrated sulfuric acid —Specific gravity, 1.84.
(b) Fuming nitric acid—Specific gravity, 1.50.
(C) Concentrated nitric acid—Specific gravity, 1.42.
DETERMINATION.
Place 100 cc. of the sample in a 500 cc. Kjeldahl flask and distil in a current of live
steam until 400 cc. of distillate are collected. Transfer the distillate and residue to
separatory funnels and tap the water off. Return the separated oil from the distillate
to the Kjeldahl flask, cool in ice water and treat with 50 cc. of concentrated sulfuric
acid. (The acid should be added slowly and the mixture constantly agitated.) When
the reaction is complete, cool thoroughly and add 25 cc. of water. Distil the poly-
merized mixture in a current of live steam, collecting 900 cc. of distillate. Add the
separated oil from this distillate to the residue from the first distillation.
Place a volume of fuming nitric acid, equal to three times the volume of the com-
bined oils, in a separatory funnel and cool thoroughly in ice water. Add the com-
1922] VIEHOEVER: VOLUME WEIGHT OF CRUDE DRUGS AND SPICES 553
bined oils, drop by drop, shaking carefully and keeping the mixture cool. After all
the oil has been added, allow to react a few moments and draw off the acid layer. Wash
the remaining oil once with fuming nitric acid, twice with strong nitric acid and finally
several times with water. Measure the volume and determine the refractive index.
(3) That the method of Grotlisch and Smith! for the determination of
coal tar oils in turpentine be studied.
VOLUME WEIGHT DETERMINATIONS OF CRUDE DRUGS
AND SPICES.
By Arno VIEHOEVER (Bureau of Chemistry, Washington, D. C.), Asso-
clale Referee.
The subject of volume weight and its importance in drug inspection
has been discussed in previous reports? of the Associate Referee on
Medicinal Plants.
The work for 1921 followed the two following distinct lines:
Method I.
This method, determining the weight of a certain volume, is prac-
tically the same as that adopted in grain standardization’, except that
it is more simple in that the special Boerner apparatus is not used.
It consists in filling a graduated cylinder up to the mark with the
material of questionable quality, determining its weight and repeating
the same procedure with a sample of the drug of good quality.
Method II.
This method determines the apparent, or absolute specific weight of
substances in the Kunz-Krause apparatus‘. The slightly modified ap-
paratus used to obtain the data recorded in the table consists of two
parts, one fitting, with a ground joint, into the other. (See Fig. 2.)
The capacity of 100 cc., to the mark in the neck, was found to be a
suitable size. In order to ascertain the usefulness of the apparatus it
was submitted to collaborators, together with test material and the
following instructions: :
(1) Standardize pycnometer by filling it from a buret with water at a known tem-
perature (approximately 20°C.) to a conyenient point in the stem and marking this
point. The reading on the buret will be the volume of the pycnometer.
(2) Take a given weight of a chosen drug (say 20 grams) and transfer to the empty
pycnometer from which the cover has been removed.
(3) The liquid considered suitable for filling the pycnometer is kerosene which has
been dehydrated with anhydrous sodium sulfate. Replace the cover and fill the pycnom-
1J. Ind. Eng. Chem., 1921, 13: 791.
2 J. Assoc. Official Agr. Chemists, 1920, 4: 154; 1921, 4: 412.
3U.S. Dept. Agr. Bull. 472.
4 Ber. pharm. Ges., 1919, 2: 150.
554 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
eter at the same temperature, from a buret containing the kerosene, through the neck
of the pycnometer to the mark in the stem. Where the specific gravity of powders is
being determined it might be better to introduce a given volume (say 10 cc.) of the
liquid into the pycnometer before introducing the drug. The difference between the
volume of the pycnometer and the amount of the liquid used will be the volume of the
material.
weight of material ;
Then specific gravity of the material = =
volume of material
Materials suggested for the test are fruits such as caraway, fennel, oval and ordinary
coriander; seed such as mustard seed; various powdered vegetable drugs such as pepper,
hydrastis and senna; spore drugs, such as Lycopodium; and other drugs, such as
Lupulin and Kamala.
Fic. 1—Bornner’s SpeciaL APPARATUS FOR TESTING WerIcuT PER Busner, Tae Horrer ts SwuNa@ TO
THE LEFT. THE FILLED TEST KETTLE BALANCES THE SPECIAL BEAM.
The results of determinations are believed to be useful in suggesting the presence
of foreign material such as dirt and sand; in indicating the quality of the drug, such as
X
or
oO
1922] VIERROEVER: DETERMINATION OF CRUDE DRUGS AND SPICES
immature or inferior drugs and partially or wholly extracted plant products; and per-
haps in indicating also the species of closely related seed, as in the case of mustards
and other Brassica seeds grown mainly for their fixed-oil content.
APPARATUS FOR VOLUME WEIGHT DETERMINATION.
Fic. 2—Tue Parts SHown Are Fitrep TOGETHER WITH A Ground Joint. X }4.
DISCUSSION OF RESULTS.
Analytical data are available on both methods, but are especially
numerous on Method I. (See former reports.) From a critical study
of the data on Method I, it is apparent that considerable variation exists,
even in material of practically the same quality. It seems evident that
the manner of filling the cylinder with the dry substances enters ma-
terially into consideration, and explains the varying and unsatisfactory
results. Similar observations had been made in the work on grain
standardization and led to the devising of special apparatus, which
determines the rate of flow and amount of material put into the measure.
(See Fig. 1).
556 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
TaBLe 1.
Volume weight determinations.
E. oO. c. K. R. G. c. Ss.
PRODUCT CONDITION! yFaton* | GLycARTt| CAPENt BRINTON
Acheen pepper Site Shjsei in aeericios Whole beac ieee 0.85 eee
Acheen pepper feepe cee eer oent: Ground Bite 1.42 1.36 1.33
Aleppey peppenigesa enc cie ete. Whole Soko Wate 1.13 sabe
Aleppey: peppersetenmen cuisine Ground 1.33 12, 1.36 1.33
Yellow: mustardsace ee eee eee eee Whole ete +, aos oe 1.19-1.20
White;mustardie emer ae ee ree Whole 1.20 apa
California Trieste eee eee ee Whole 1.15
Japanese*mustards epee eee Whole Fetes mca 1.12 vito
Ghinese mustard eee Whole 1.20 1.14 1.16 1.19
1.143**
1.136**
1.162**
Chinese’ colza’: Bae eer re eee Whole 1.162 1.17 1.16 1.14
Coffee, green, (short berry)........ Whole Ae: ee a. 1.22
Coffee, green, Mocha.............. Whole Ss eat Soi 1.21
Caraway seed Breer it. canis Whole ae nee ae | | LISTS
1.12 1.16
Coriander..:.......QQe eee ie. ote Whole here aes See 0.60
Poppy, seed (bine) hres. eee Whole sty ae Per .... |1.10—1.15
*U.S. Food and Drug Inspection Station, San Francisco, Calif.
TU. S. Food and Drug Inspection Station, Chicago, Ill.
{Bureau of Chemistry, Washington, D. C.
U.S. Food and Drug Inspection Station, Philadelphia, Pa.
**Practically free from foreign seeds and sand.
Where there is obvious difference in anatomical structure, such as
in Acheen pepper—with many practically empty fruits—and_ Tilli-
cherry pepper, even the crude method of using the graduate cylinder
yields useful results.
Method II eliminates the element of chance in filling, though care
must be taken that no air bubbles remain.
The data in the table, while limited, are very suggestive. They
show that the results obtained by different collaborators with the same
material agree fairly well. It is interesting to note that the difference
existing in the specific gravity of whole Acheen and Aleppey peppers
does not exist in the ground material Somewhat different results were
expected, owing to the fact that Acheen pepper contains more shell
and less starch than Aleppy. Eaton’s results with different samples
of Chinese mustard are worthy of special consideration. He points out
that the sample with the highest specific gravity was adulterated with
considerable dirt, sand and foreign seeds. The extent of usefulness of
the apparatus is not definitely established.
COMMENTS ON THE METHOD.
E. O. Eaton.—lf the San Francisco samples are properly identified and apparatus is
satisfactory, it would appear that the method would be of value as a means of identi-
fication only if samples are clean and free from foreign material.
1922] VIEHOEVER: MICROSUBLIMATION OF PLANT PRODUCTS 557
C. S. Brinton.—I am not sure of the value of this determination until enough data
has been obtained to show the maximum, average and minimum results on each pro-
duct.
COMMENTS ON THE APPARATUS.
E. 0. Eaton.—The apparatus does not appear to hold kerosene well as it creeps out
from ground-glass connections. A Jead ring was used to weight it down. A non-
greased buret (100 cc.) was used, the ground-glass connections being lightly water
sealed.
C. K. Glycart.—It was noted that leakage resulted unless the ground-glass surfaces
of the pycnometer were held firmly in place. It is suggested that a suitable clamp be
devised, especially to insure the same adjustment of the volume.
C. S. Brinton.—I have measured one of our cream bottles and believe that the centri-
fuge and these wide-neck bottles would help considerably in getting more accurate
results with many products as coriander, caraway, coffee, etc., which are rough and
have crevices where air can be entangled. These cream bottles hold about 45 cc. and
have a neck about 10 mm. inside diameter. They will easiiy hold 20 grams of most
material. I should like to have tried this modification of your method but time did
not permit.
RECOMMENDATION.
It is recommended that the study of volume weight determinations
be continued with the assistance of collaborators.
MICROSUBLIMATION OF PLANT PRODUCTS.
By Arno VieHoEVER (Bureau of Chemistry, Washington, D. C.),
Associate Referee.
The sublimation experiments! reported at the 1920 meeting, were
continued with the collaboration of Ruth G. Capen and Joseph F.
Clevenger. The apparatus consisted of a small beaker-like container
with a small cup (approximately 11 cm.) extending from the bottom.
The cup, containing the plant material, is heated in a cottonseed oil bath
to the desired temperature. A small glass is placed over the opening
and serves as a receiver for the sublimate. Some experiments were
also made with an apparatus somewhat similar to that of Eder? in which
vacuum and cooling were applied. Different plant products were
tested with the results indicated below:
Artemisia cina and A. neo-mexicana.
The flowerheads of these plants were heated in the sublimation ap-
paratus. Santonin was obtained in a characteristic crystalline form
and further identified in the following manner:
1 J. Assoc. Official Agr. Chemists, 1921, 4: 414. A :
2Uber die laste bbe yon Alkaloiden im luftverdiinnten Raum. Schweiz. Wochschr., Chem.,
Pharm., 1913, 51: 228-31, 241-5, 253-6.
558 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Identification of Santonin—
(1) Reaction with alcoholic furfural solution.—The sublimate was dis-
solved in a very small amount of alcohol, to which 1 or 2 drops of alco-
holic furfural solution and 1 to 2 cc. of sulfuric acid were added. Upon
evaporation of the alcohol and especially after heating, the liquid is
colored distinctly purplish red to carmine red; the color changes to
bluish violet and deep blue, and finally shows a black precipitate. Alco-
holic furfural alone with sulfuric acid, upon standing gives a pink or
reddish color.
(2) Precipitation with hydriodic acid.—Hydriodic acid containing free
iodine is added to an alcoholic solution of santonin. An olive green or
greenish brown precipitate is formed, which shows characteristic crystal-
lization, especially after the excess of the hydriodic acid is removed by
decanting. Other reagents, such as ferrocyanic acid, ferricyanic acid
and cobalticyanic acid did not give satisfactory results'. Both Capen
and Clevenger obtained the crystals of santonin hydroperiodide,
(CisHis0s) oI HI.
FIG. 1—X110
CRYSTALS OF SANTONIN HYDROPERLODIDE.
1Wedekind, E. Beitrage zur Kenntnis des Santonins Arch. Pharm., 1906, 244:
1922] VIEHOEVER: MICROSUBLIMATION OF PLANT PRODUCTS 559
Ilex cassine Miche.
The fruits and seeds, upon microsublimation, yielded no caffeine.
The leaves yielded caffeine which showed the characteristics of caffeine
crystals.
Identification of Caffeine—
When treated with gold chloride solution, the crystals yielded yellow
needles arranged in characteristic cluster form. They were, however,
decomposed by water and alcohol. Very satisfactory crystals were
obtained by the author and his collaborators upon addition of mercuric
bichloride solution’. The change is especially characteristic if the bi-
chloride solution is added directly to the sublimate and the transform-
ation of crystals is observed under the microscope.
Piper cubeba and Piper ribestoides.
The sublimation of Piper cubeba var. rinoe katoentjor and Piper
ribesioides, carried out with the collaboration of Capen, yielded interest-
ing results. In both cases an oily sublimate was obtained; that of
Piper ribesioides showed no crystals, even after treatment with ether,
while that of Piper cubeba showed distinct needle-like crystals, which
formed especially well after treatment with ether.
Identification of Cubebin—
Attempts to obtain diagnostic crystals by the addition of benzoyl-
chloride to the cubebin sublimate have not been successful.
The blood-red color reactions with concentrated sulfuric acid is most
characteristic. In the presence of traces only, a red tint was observed.
Clevenger proved that a mixture of 50 parts of sulfuric acid with 50
parts of phosphoric acid was preferable to concentrated acid in the
examination of the cubebs as well as of the sublimate.
Hydrastis canadensis—Hydrastine.
The sublimation of Hydrastis canadensis and the substitute Jeffer-
sonia diphilla was carried out with the collaboration of Clevenger. In
the case of Jeffersonia no crystalline sublimate was obtained, whereas
goldenseal (Hydrastis canadensis) readily yielded numerous colorless
crystalline structures.
RECOMMENDATION.
It is recommended—
That the study of the microsublimation of plant products be con-
tinued with the assistance of collaborators.
1Stevenson, C. H. Microchemical Tests for Alkaloids, 1921, Plates I and VIII.
560 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
IDENTIFICATION OF CRUDE DRUG SUBSTITUTES.
By Arno VIEHOEVER (Bureau of Chemistry, Washington, D. C.),
Associate Referee.
In the report for 1920 the associate referee pointed out the character-
istics useful in the identification of Spanish digitalis and Egyptian hen-
bane. The association approved the recommendation that the method
used be studied by collaborators. The distinguishing characteristics
were checked by other workers and the following statements were
submitted:
SPANISH DIGITALIS.
E. N. Gathercoal.—There is no question but that your characteristics distinguishing
Spanish from official digitalis are very well described. I can offer no suggestions for
improvements whatsoever.
E. E. Stanford—In regard to the characteristics of the two species of digitalis, my
observation corresponds with yours. I believe, however, the margin of the Spanish
digitalis is serrate, or biserrate, at least in some leaves. This characteristic has ap-
parently, by inadvertence, been omitted from the printed description. As to the color
of the drug, I recall very plainly the yellowish green character of the commercial sam-
ples which we had in the laboratory.
C. W. Ballard—Margin of the Digitalis thapsi L. irregularly and minutely serrate
dentate. In powdered materials the heads are apt to break from the glandular hairs.
This fact might lead to confusion in the examination of powdered materials.
After receiving the reports of collaborators the method of identifi-
cation' was amplified as follows:
Digitalis purpurea L.
Stems.—Usually present in small amounts or lacking in the drug.
Digitalis thapsi L.
Leaves.—Margin unequally serrate; veins less prominent.
Stems.—Usually present in large amounts in the drug.
EGYPTIAN HENBANE
E. N. Gathercoal—Regarding the Egyptian henbane, compared with the official
drug, I have had very little opportunity of study. All of the samples of Egyptian
henbane that I have met with consist of stems with no leaves or a small quantity of
much broken leaves. I have never seen a whole leaf. Therefore, characteristics of
the whole leaf probably would be of very little value to the examiner. However, your
description of the microscopic distinction is good.
E. E. Stanford—In regard to the two specimens of henbane, the sample submitted
in my previous experience of Egyptian henbane does not enable me to corroborate or
not to corroborate some of the characteristics you attribute to that species. The
samples sent us, and almost all the other samples I have seen, consisted almost entirely
of stems. Only small fragments of leaves were present. Likewise the capsules and
the fragments of flowers were too much broken to enable me to check up their com-
1 J. Assoc. Official Agr. Chemists, 1921, 4: 410.
1922] VIEHOEVER: IDENTIFICATION OF CRUDE DRUG SUBSTITUTES 561
parative length and prolongation. The light color of all this material which I have
seen differentiates it sharply in the powder from the much greener, or grayish green
shade of the powdered official henbane. This character or color and the microscopic
evidence of a composition almost entirely of lignified stem tissues seem to me to be as
valuable indications of the identity of powdered Egyptian henbane as the characters
of the hairs. If one had to deal with a mixture of the two species, in which a relatively
small proportion of Egyptian henbane was present, or with a sample of ground official
henbane stems, the characteristics of the hairs which you enumerate would be corre-
spondingly more valuable.
_C. W. Ballard—The distinguishing characteristics are very well stated. No com-
ments are offered.
The method! of identification has been slightly amplified as follows:
Hyoscyamus niger L.
Stems.—Usually present in small amounts in the drug.
Hyoscyamus muticus L.
Leaves.—Usually much broken.
Stems.—Usually predominating in the drug.
FALSE CUBEBS.
The differentiation of cubebs and their substitutes was taken up as
new work. The following table of distinguishing characteristics was
submitted to the collaborators:
TaBLe 1.
Distinguishing characteristics of cubebs*.
Fruit Piper cubeba var. rinoe | Piper cubeba var. rinoe | Piper ribesioides.
katoent jor badak
Shape Nearly globular Nearly globular Nearly globular
Size 3-6 mm. diam. 3-6 mm. diam. 5-8 mm. diam.
Color Dark brown to grayish | Grayish Light gray to
black dark brown.
Thecaphore 5-7 mm. long 5 mm. long Up to 13 mm.
(fruit stem)
Stone cells
Treated with con-
centrated sul-
furic acid
Odor of ether ex-
tract
Inner layer radially
elongated
Red to crimson
Normal
Scattered through tis-
sue of epicarp
Deep brown
Mace-like
*Compiled from literature and personal observations.
The following comments were received:
1 J. Assoc. Official Agr. Chemists, 1921, 4: 411.
long.
Inner layer most-
ly isodiametric
Brownish
Somewhat tur-
pentine-like
562 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
E. N. Gathercoal.—There is no question that the fruit of Piper ribesioides is generally
larger, with a longer thecaphore, lighter in color, with isodiametric stone cells, a some-
what turpentine-like odor and responds with a brownish color when treated with con-
centrated sulfuric acid. We were not able to find any of the globular heads that were
larger than 7 mm. in diameter and in a few instances the thecaphore measured more
than 13 mm. long.
I was unable to distinguish Piper cubeba var. rinoe badak from Piper cubeba var.
rinoe katoentjor except by the sulfuric acid test.
Of the 71 fruits, 15 turned brown instead of crimson red with concentrated sulfuric
acid. Of these 3 were gray brown or grayish tan, 5 reddish brown and 7 dark brown.
From your sample of the mixed varieties, of 4 selected light gray fruits, 3 reacted crimson
and 1 brown with concentrated sulfuric acid. Of 4 selected dark brown fruits, 1 was
brown with concentrated sulfuric acid and 3 were crimson.
Regarding the color of these varieties: We found in an examination of 2.890 grams of
the mixed samples that there were 0.135 gram of stem, 0.690 gram formed by 48 very
immature fruits and 71 fairly well formed fruits weighing 2.150 grams. These 71
fruits, by a careful examination of their color in a good light against a white background,
were divided as follows:
Cotor No. or Fruits CoLor No. oF Fruits
Blackishterc cee a. 1 Reéd-brown os... sacle eee 20
Dark DOWN cere craters iecetes 28 MOAMDEOWN«.. 55 0,: 12068 oe Eee 8
Dark brown with gray spots.... 6 Light gray or gray-tan.......... 3
Gray-DIOWN. Sec scces see eee 3
I could find no distinction between the two varieties in the character or arrangement
of the stone cells in the tissues of the pericarp.
C. W. Ballard—Stone cells appear scattered through the mesocarp of the Piper
cubeba (rinoe badak) and the oil glands or cells appear much darker in color than in
the other varieties. This difference may be due to the long boiling preliminary to
sectioning but all samples were boiled the same length of time.
Heber W. Youngken.—I was able to verify most of the distinguishing characteristics
on the list you submitted. I find, however, working on the material you sent me, the
following characteristics which are at variance with the observations of your depart-
ment. The color of the fruits of Piper ribesioides varies from light gray to light brown
to dark brown. The thecaphore of Piper cubeba var. rinoe kaloentjor showed a range
in length from 5-9 mm.; Piper cubeba var. rinoe badak was 5-11 mm. long. * * *.
All of these observations were checked by each of my advanced pharmacognosy students
and verified.
The modified method of identification is as follows:
1922] VIEHOEVER: IDENTIFICATION OF CRUDE DRUG SUBSTITUTES 563
TABLE 2.
Cubebs and substitutes*.
Fruit Piper cubeba var. rinoe | Piper cubeba var. rinoe | Piper ribesioides
katoentjor badak
MACROSCOPIC CHARACTERS
Shape Nearly globular Nearly globular Nearly globular
Size 3-6 mm. diam. 3-6 mm. diam. 5-8 mm. diam.
Color Dark brown to grayish | Grayish Light gray to
black dark brown
Thecaphore 5-9 mm. long About 5 mm. long Up to 13 mm.
(fruit stem) long
MICROSCOPIC CHARACTERS
Stone cells Inner layer radially | Scattered through tis-| Inner layer radi-
elongated sue of epicarp ally isodia-
metric.
CHEMICAL CHARACTERS
Treated with con-| Red to crimson Deep brown Brownish
centrated sul-
furic acid
Odor of ether ex- | Normal Mace-like Somewhat _tur-
tract pentine-like
Sublimate White needle-like | Oily mass, no crystals | Oily mass, no
crystals crystals.
*Compiled from literature and personal observations.
RECOMMENDATIONS.
It is recommended—
(1) That the modified method for the macroscopic and microscopic
identification of Digitalis thapsi L. (Spanish digitalis), a recent substitute
for Digitalis purpurea L., be adopted as a tentative method.
(2) That the modified method for the macroscopic and microscopic
identification of Hyoscyamus muticus L. (Egyptian henbane), a sub-
stitute for Hyoscyamus niger L. be adopted as a tentative method.
(3) That the method for the macroscopic, microscopic and micro-
chemical identification of cubebs (Piper cubeba var. rinoe katoentjor and
its substitutes, Piper cubeba var. rinoe badak and Piper ribesioides Wall.,
be adopted as a tentative method.
564 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
REPORT ON ALKALOIDS.
By A. R. Buss, Jr.! (Emory University School of Medicine, Emory
University, Ga.), Associate Referee.
The work on alkaloids for 1920-1921 involved (a) a study of the
volumetric check on the weight of strychnine found by the assay for
strychnine in tablets; (b) a study of a similar check in the assay for
strychnine in liquids; (c) a study of the associate referee’s method for
the separation of quinine and strychnine’; (d) a study of the method for
the assay of physostigma and its preparations’; (e) a study of a modi-
fied United States Pharmacopceia method for the assay of fluidextract
of hyoscyamus‘; and (f) a comparative study of the volumetric and
gravimetric methods for the assay of ipecac and its preparations.
Carefully prepared samples and detailed instructions for the esti-
mations were sent to F. W. Heyl, Upjohn Co., Kalamazoo, Mich.;
E. M. Bailey, Connecticut Agricultural Experiment Station, New
Haven, Conn.; E. C. Merrill, United Drug Co., Boston Mass.,; H. B.
Mead, U. S. Food and Drug Inspection Laboratory, New York, N. Y.;
G. E. Ewe, H. K. Mulford Co., Philadelphia, Pa.; Hugo H. Schaefer,
Columbia University, College of Pharmacy, New York, N. Y.; L.
Schwartz, U. S. Food and Drug Inspection Laboratory, New York,
N. Y.; and M. F. Brownand W. H. York, Emory University Medical School,
Emory University, Ga. Albin Stikarsfsky carried out the actual work
on the samples submitted to E. C. Merrill, and R. E. Andrews carried
out the work on the samples submitted to E. M. Bailey.
ASSAY FOR STRYCHNINE IN TABLETS.
Carefully prepared tablet triturates, each containing 0.00043 gram of
strychnine (standardized), were submitted to collaborators for assay
by the following method:
Place 25 tablets in a 200 cc. Squibb separator and moisten with 8 cc. of water. Add
1 ce. of stronger ammonia water. Agitate with 25 cc. of chloroform and allow the
mixture to stand until separation is complete. Draw off the chloroform into a second
separator and repeat the agitation twice with 25 ce. portions of chloroform. Wash
the combined chloroformic fractions with 10 cc. of distilled water and allow the mixture
to stand 15 minutes. Introduce a pledget of absorbent cotton into the stem of the
separator and run off the chloroform into a tared dish. (Do not allow the wash water
to enter the orifice of the stop-cock.) Add 10 ce. of chloroform to the contents of the
separator, and when the water has entirely risen to the surface run this chloroform also
into the tared dish. Wash the outer and inner surfaces of the stem of the separator
with a little chloroform, adding this also to the contents of the tared dish. Evyaporate
the chloroformic solution on a steam bath, using a fan or blower. Remove the dish
1 Presented by A. G. Murray
aT. prs Agr. Chemists, 1021, 4: 416.
3 [hid.,
4 Ibid. 419.
1922] BLISS: REPORT ON ALKALOIDS 565
from the bath as the last portions of chloroform evaporate, to avoid decrepitation.
Dry at 100°C. to a constant weight and weigh as strychnine. (The U.S. P. factor for
strychnine to strychnine sulfate is 1.2815.) Check the weight of the strychnine by
dissolving the residue in neutral alcohol, adding an excess of 0.1N sulfuric acid, and
titrating back with 0.02N potassium hydroxide, using methyl red as the indicator.
(1 ce. of 0.1N sulfuric acid is equivalent to 0.0334 gram of strychnine or 0.0428 gram of
strychnine sulfate.)
TABLE 1.
Volumetric check in the resulls of assays for strychnine in tablets*.
ANALYST GRAVIMETRIC VOLUMETRIC
f METHOD CHECK
= gram gram
G. E. Ewet 0.0107 0.0133
0.0104 0.0133
A. Stikarsfsky ft 0.0127 9.01282
0.0126 0.01216
0.0128 0.01250
M. F. Brown 0.0108 0.0105
0.0106 0.0104
0.0103 0.0107
W. H. York 0.0106 0.0109
0.0104 0.0106
Bossy |W Yeree eta
A. R. Bliss, Jr. 0.0107 0.0110
0.0105 0.0103
0.0104 0.0109
Average....... 0.01103 0.01149
Theoretical. ..... 0.01075 0.01075
* 25 tablets used. A :
+ For some unaccountable reason the volumetric method gave results in excess of the gravimetric method,
but in view of the very small quantity of alkaloid worked upon and the very small amount of standard
acid consumed, the results have value as checks.
t Both methods seem to give results which are almost identical.
Comments.—Although the average gravimetric result is 0.01103 as compared to the
theoretical quantity 0.01075, and the average volumetric result obtained by the same
collaborators is 0.01149 as compared to the theoretical quantity 0.01075, when the
small quantities of alkaloids worked with and the fact that the above averages are
very much closer to the theoretical when the results of the second series listed in Table 1
are eliminated, are taken into consideration, it will be readily seen that both the method
and the volumetric check are quite satisfactory.
566 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
ASSAY FOR STRYCHNINE IN LIQUIDS.
(In the absence of other alkaloids.)
A carefully prepared elixir containing 0.0648 gram of strychnine
(standardized) in 50 cc. was submitted to collaborators for assay by the
following method:
Place about 50 cc. of the sample, accurately measured or weighed, into an evapora-
ting dish and evaporate off the alcohol. Transfer to a 250 cc. Squibb separator. Add
an excess of ammonia water and 25 cc. of chloroform. Agitate thoroughly and allow
the mixture to stand until separation is complete. (Proceed as under the assay for
strychnine in tablets, page 564.)
TABLE 2.
Results of assays for strychnine in liquids.
GRAVIMETRIC VOLUMETRIC
ANALYST METHOD CHECK
gram gram
G. E. Ewe. 0.0668 0.0671
0.0665 0.0680
A. Stikarsfsky* 0.0636 0.0548
0.0585 0.0542
0.0581 0.0542
F. W. Heylt 0.0616 0.05768
0.0622 0.05010
0.0581 0.05010
M. F. Brown. 0.0638 0.0598
0.0635 0.0636
Tost ke sseebee
W. H. York. 0.0637 0.0632
0.0599 0.0635
OSGeo oh || waesistins
A. R. Bliss, Jr. 0.0650 0.0644
0.0645 0.0642
0.0639 0.0632
Average........ 0.06284 0.05994
Theoretical... . . . 0.0648 0.0648
* The volumetric determination seems to give invariably lower results. The drying to constant weight
at 100°C. is rather prolonging the assay. fo my mind the volumetric estimation, if reliable, is quicker
and leas troublesome.
t Oils troublesome.
1922] BLISS: REPORT ON ALKALOIDS 567
Comments.—The results obtained by six collaborators, as shown in Table 2, indicate
that both the method and the volumetric check are quite satisfactory.
METHOD FOR SEPARATING QUININE AND STRYCHNINE.
A carefully prepared elixir containing 0.7776 gram of quinine (standard-
ized) and 0.0258 gram of strychnine (standardized) in 50 cc. was used.
_ The method submitted has been published’.
TABLE 3.
Results of separation of quinine and strychnine.
ANALYST QUININE STRYCHNINE
a gram gram
G. E. Ewe. 0.7875 0.0215
0.7774 0.0200
A. Stikarsfsky* 0.5428 0.02809
0.5490 0.02788
0.54325 0.02774
F. W. Heylt 0.7878 0.0255
0.7762 0.0249
lost 0.0252
R. E. Andrewst 0.7695 0.0222
0.7690 0.0245
M. F. Brown 0.7765 0.0251
0.7772 0.0246
W. H. York 0.7768 0.0219
0.7699 0.0242
AVEEABEG se. 5) <'-.5)2 0.7232 0.02452
Theoretical. ..... 0.7776 0.0258
* Some resinous material remaining behind in gravimetric alkaloidal residue increases its weight, thus
raising the amount of total alkaloids. During the extraction of quinine with ether flocculent resinous
flakes separate and stick to the walls of funnel.
+ Not enough ether to remove oils.
t Strychnine residue gave positive tests for quinine.
Comments.—The results obtained by six collaborators (not including the results
obtained in a long series of experiments by the associate referee), as found in Table 3,
indicate that this method is quite satisfactory and gives much more accurate results
ee eee
1 J. Asso. Official Agr. Chemist, 1921, 4: 416.
568 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
than the oxalate method!, the tartrate method? or the ferrocyanide method as modified
by Simmonds’.
ASSAY OF PHYSOSTIGMA AND ITS PREPARATIONS.
A manufacturer’s extract of physostigma said to contain from 1.7 to
2.3 per cent of alkaloids was used.
The methods submitted for the assay of physostigma, fluidextract of
physostigma (for alkaloids) and the tincture of physostigma (for alka-
loids) have been published‘.
TABLE 4.
Results of assays of extract of physostigma.
Se U.S. P. SUBMITTED
METHOD METHOD
per cent per cent
A. Stikarsfsky* 1.775 1.635
1.782 1.643
1.787 1.651
M. F. Brown 1.776 1.8460
1.784 1.8645
1.785 1.8649
W. H. York 1.782 1.8527
1.788 1.8682
UTZ 1.8478
A. R. Bliss, Jr. 1.789 1.8578
1.786 1.8605
1.782 1.8608
Average........ 1.782 1.80518
* The alkaloidal residue seems to be rather dark for titration by this method (submitted method), still
it works well with methyl red.
Comments.—The results obtained by Ewe’ and the associate referee and his col-
laborators, as shown in Table 4, indicate that the U. S. P. method gives much lower
results (doubtless due to partial decomposition of the alkaloid and to incomplete
extraction) than those obtained with the method recommended, which has proved
quite satisfactory.
ASSAY OF FLUIDEXTRACT OF HYOSCYAMUS.
A fluidextract very carefully prepared according to the method of
the United States Pharmacopoeia from a standard drug was submitted
1A. H. Allen, Commercial Organic Analysis, 4th ed. 1912, 6: 461.
2 [bid., 462.
2 Analyst, 1914, 39: 81.
4 J. Assoc. Official Agr. Chemists, 1921, 4: 418.
5 J. Assoc. Official Agr. Chemists, 1921, 4: 419.
1922] BLISS: REPORT ON ALKALOIDS 569
to the collaborators to be assayed by the method given in the United
States Pharmacopceia! with the following changes as suggested by H.
C. Fuller, Institute of Industrial Research, Washington, D. C.:
Proceed as directed under ‘‘Fluidextractum Belladonne Radicis’”, first line of the
assay, modifying the process there by using 25 mils of the fluidextract of hyoscyamus
in place of 10 mils of fluidextract of belladonna root, and adding at least 30 mils of
distilled water and 5 to 10 mils of stronger ammonia water, and before titrating treating
the residue twice with 5 mils of ether and evaporating to dryness each time.
TABLE 5.
Results of assays of fluidextract of hyoscyamus.
U. S. P. MODIFIED
ANALYST METHOD METHOD
2 gram gram
G. E. Ewe* 0.0423 0.0477
0.0423 0.0477
A. Stikarsfsk y 7 0.0466 0.0420
0.0489 0.0396
0.0494 0.0396
M. F. Brown. 0.0465 0.0520
0.0458 0.0512
0.0456 0.0515
W. H. York. 0.0452 0.0507
0.0460 0.0518
0.0455 0.0518
A. R. Bliss, Jr. 0.0450 0.0505
0.0459 0.0515
0.0452 0.0506
AV erage -irara ctays05 0.0457 0.0484
* There is no doubt that the extra ammonia is desirable; it is the regular practice in this laboratory.
+ The modified method gives invariably lower results. This is in my estimation due to the use of too
much stronger ammonia water (10 mils). All evaporation was done on a water bath (not steam bath)
until about 2 mils remained. These were evaporated in moderately hot water (not boiling). A too
alkaline medium seems to hasten hydrolysis.
Comments.—The results of the modification of the U. S. P. method for the assay of
fluidextract of hyoscyamus, obtained by five collaborators (Table 5), indicate that the
recommended method is quite satisfactory.
1U. S. Pharmacopeeia, IX, 1916: 187.
2 [bid., 178.
570 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
ASSAY OF IPECAC AND ITS PREPARATIONS.
Method for emetine bismuth iodide.
Weigh accurately about 0.5 gram of the salt into a glass-stoppered flask. Add
10 ce. of water and 3 cc. of ammonia water, shake and allow to stand 10 minutes. Add
50 ce. of ether, shake 10 minutes and then every 10 minutes during 2 hours. Decant
25 ce. of the ethereal layer into a 25 cc. graduated flask. Filter this through a pledget
of cotton into a small tared beaker. Wash the flask and the filter with ether and add
the washings to the contents of the tared beaker. Allow the ether to evaporate spon-
taneously, dry at 100°C. and weigh as anhydrous emetine. Multiply this weight by
2. The result is the weight of the total alkaloid in the sample.
Take up the alkaloidal residue with an excess of 0.02N sulfuric acid and titrate the
excess with 0.02N sodium hydroxide, using cochineal as the indicator. Each ce. of
0.02N sulfuric acid consumed is equivalent to 0.0048 gram of anhydrous emetine.
It is impossible to present tabulated results as but two collaborators
reported. However, the following data submitted by Ewe is important
and interesting:
NOTES ON PREPARATION OF EMETINE.
The method outlined by DuMez! consisted of precipitating an acidified aqueous
solution of emetine hydrochloride with Dragendorff’s reagent*, collecting and washing
the precipitate with water and drying it in the air at a temperature below 50°C. When
so prepared the compound has an ugly brick-red color. But if the product is made by
precipitating an acidified aqueous solution of emetine hydrochloride with Dragendorff’s
reagent, then warming the mixture slightly until the maximum bright red color con-
sistent with no alteration of the emetine alkaloid is attained, a more beautiful and
thoroughly combined product is obtained. The amount of heat required to effect the
combination must be carefully controlled by experiment in order to prevent alteration
of the emetine alkaloid which is sensitive to heat under the conditions of manufacture
of this compound. The difference in results of alkaloidal assays of this compound
by gravimetric and volumetric methods is a measure of the heat control; the volumetric
method gives results only for unaltered alkaloid whereas the gravimetric method in-
cludes both altered and unaltered alkaloid. Therefore a properly made compound
should give results which check closely by both methods.
Table 6 shows the results of assays of a number of samples of emetine bismuth iodide
from various sources, by both volumetric and gravimetric methods.
Regarding the proper precautions to be taken in the assay method: All analyses,
the results of which are given in Table 6,were made by placing about 0.3 gram samples
in a separator, adding ether, decomposing with ammonia water, shaking out the alka-
loid and collecting the ether extractions in a tared flask, recovering the ether and drying
the residue of emetine alkaloid at 60°C., in the case of the gravimetric method. In
the case of the volumetric method, the ether extractions were evaporated spontaneously
in a beaker and the recovered alkaloid titrated as usual. It is essential that the ipecac
alkaloids be protected from overheating. This can be accomplished by either evapo-
rating the collected ether extractions spontaneously or, in order to save time, evapora-
ting the collected ether extracts to small volume on the steam bath in a manner which
prevents the steam from impinging on the flask anywhere except where it is in contact
with the ether extracts and then finally evaporating the balance of the ether spon-
taneously. The proper heating of the flask can be accomplished by means of a steam
1 Philippine J. Sci., 1915, 10: 73.
2Z. Analyl. Chem., 1866, 5: 407.
1922| BLISS: REPORT ON ALKALOIDS 571
bath covered with removable rings, only the smallest ring being removed and the flask
being placed directly over the small opening.
TABLE 6.
Results of assays of anhydrous emetine alkaloid.
SAMPLE GRAVIMETRIC VOLUMETRIC
No. METHOD METHOD
per cent per cent
1 26.99 21.3
2 22.85 17.94
3 27.75 19.84
4 27.4 14.63
5 28.2 28.2
6 24.8 24.8
7 20.2 25.13
8 26.0 23.15
9 25.02 23.35
10 29.8 23.4
11 24.82 24.6
12 19.84 19.3
13 27.0 21.5
14 22.5 14.1
15 22.8 17.6
16 32.7 31.5
17 22.5 22.1
18 28.2 28.2
It has been my experience that the sensitiveness of the ipecac alkaloids to heat is
real but overrated. For instance, I made some experiments in 1914 along this
line which I reported at the annual meeting of the American Pharmaceutical Associa-
tion! that year as follows: “If the alkaloids of ipecac obtained during the assay process
are allowed to remain on the steam bath after the ethereal layer has evaporated, darken-
ing and disintegration of the alkaloids result. Of three experiments in which the
alkaloids were kept at water-bath temperature for five minutes after the ethereal sol-
vent had evaporated, 6.7%, 6% and 3% of the total amount of alkaloids present was
lost’. I also reported? later some experiments which I made regarding the effect of
heat on emetine hydrochloride, which are also of interest along these lines.
Manufacturers are continually reminded of the sensitive nature of the ipecac alkaloids
by the low alkaloidal yields in preparations of ipecac made by use of heat. The prep-
aration which suffers most is the solid extract. The low yields in the case of the
fluidextract are due primarily to incomplete initial extractions. It has been fairly
well established that very little alkaloid remains in the extra percolate after it has
been concentrated with heat to a small volume preparatory to adding it to the initial
percolate. All of this evidence indicates the sensitiveness of the ipecac alkaloids and
justifies the step in the assay of evaporating the ether extracts spontaneously or with
the proper precautions against overheating as outlined previously.
It is my opinion that the difference in results obtained by gravimetric and volu-
metric methods with ipecac preparations is primarily due to alteration of the alkaloids
(chiefly cephaeline) during the process of manufacture of the preparation; secondly,
to the inclusion of non-alkaloidal matter in the alkaloidal residue; and thirdly, to altera-
tion of alkaloids by the heat used during the assay. My statement that cephaeline
1 J. Am. Pharm. Assoc., 1914, 3: 1681.
2 Am. J. Pharm., 1919, 91: 275.
572 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
appears to be the offender is based on my experience in the manufacture of cephaeline
alkaloid, which is extremely difficult to produce with the high titratable value shown
by emetine.
RECOMMENDATIONS.
It is recommended—
(1) That the method for the assay for strychnine in tablets, including
the volumetric check, be adopted as an official method.
(2) That the method for the assay for strychnine in liquids (in the
absence of other alkaloids), including the volumetric check, be adopted
as an official method.
(3) That the associate referee’s method for the separation of quinine
and strychnine be adopted as an official method.
(4) That the method for the assay of physostigma and its prepara-
tions, as prestnted by G. W. Ewe, be adopted as an official method.
(5) That the method for the assay of fluidextract of hyoscyamus
(which is a simple modification of the U. S. P. method) be adopted as
an official method.
(6) That the study of the gravimetric and the volumetric methods
for the assay of ipecac and its preparations be continued.
(7) That the assay of belladonna liniment by the method prescribed
by the United States Pharmacopeia for fluidextractum belladonne
radicis!, as suggested by G. W. Ewe, be subjected to collaborative study
with a view to its adoption as an official method.
Note.—The following experiment reported by Ewe indicates the absence of any
effect of camphor on the assay: 10 cc. portions of a fluidextract of belladonna which
assayed 0.758 (duplicate 0.726) gram alkaloid per 100 cc. were placed in separators,
0.5 gram portions of camphor added and the resulting solution assayed by the U.S. P.
method for fluidextract belladonna. 0.740 gram alkaloid per 100 cc. was recovered.
(8) That the method for the assay of belladonna ointment, submitted
by G. W. Ewe, which appears below, be subjected to collaborative
study with a view to its adoption as an official method.
Place about 30 grams of belladonna ointment in an 8 ounce centrifuge bottle; add
150 ce. of a mixture of one volume of chloroform and two volumes of ether, followed by
10 cc. of ammonia water. Shake the bottle vigorously until all the fats are dissolved.
Then shake on a mechanical shaker for four hours and let settle. Pour off the clear
ethereal layer into a separator. Wash the residue in the centrifuge bottle with small
portions of the ether-chloroform mixture; shake, let settle and pour off the clear ethereal
layer. Collect the washings in a beaker, evaporate to small volume and wash the
ether-chloroform extracts contained in the separator into the mixture. Extract the
alkaloids by shaking out repeatedly with weak sulfuric acid and proceed as directed
by the U. S. Pharmacopoeia in the assay process for fluidextract belladonna root'. The
assay can be hastened by centrifuging wherever instructions are given to let the mix-
ture stand until it settles.
U.S. Pharmacopoeia, EX, 1916, 178.
1922] | GLYCART: ANALYSIS OF MORPHINE, CODEINE AND HEROINE 573
Norte.—This method is extremely accurate as shown by the following experimental
data reported by Ewe: Approximately 3 gram samples, accurately weighed, of an
assayed solid extract of belladonna leaves were placed in an 8-ounce centrifuge bottle,
and the bottle placed in a beaker of warm water until the extract was softened. 1.6 cc.
of dilute alcohol was added and worked into the extract with a thin glass rod. 10
grams of melted hydrous wool fat were poured into the bottle and mixed well. Then
18 grams of melted benzinated lard were poured in and also mixed in well with the rod.
The rod was removed, wiped with filter paper and the filter paper also placed in the
bottle. 150 cc. of chloroform-ether mixture were added, and the assay was proceeded
with as described above. The following results are typical:
PLAIN SOLID EXTRACT SOLID EXTRACT IN FORM OF OINTMENT
per cent per cent
ARSaYIING. IL) b esi... 2.023 Assay; Noo1. cece: 2.033
IKSRAVINO® 2ei:- 12.) +/h- 1.946 Assay NOs2)s 202 sea. - 1.993
Average......... 1.984 Averagesco..-. -: 2.013
(9) That work be done on methods for assaying the U. S. P. ointment
of stramonium.
(10) That work be done on methods for the determination of atro-
pine, morphine, codeine and heroine in tablets.
REPORT ON METHODS OF ANALYSIS OF MORPHINE,
CODEINE AND HEROINE (DIACETYLMORPHINE).
By C. K. Grycarr (U. S. Food and Drug Inspection Station, Trans-
portation Building, Chicago, Ill.), Associate Referee.
In accordance with the recommendation approved by the association
at the last meeting, samples of morphine, codeine and diacetylmorphine
of uniform composition were sent with directions for examination to
the collaborators. The qualitative tests and quantitative methods
submitted were substantially as reported in the preliminary work’.
The following results were obtained by the collaborators—William
Rabak, U. S. Food and Drug Inspection Station, Minneapolis, Minn.;
H. McCausland, The Abbott Laboratories, Chicago, Ill.; and E. O.
Eaton, United States Food and Drug Inspection Station, San Fran-
cisco, Calif.
COMMENTS.
E. 0. Eaton.—These methods all appear to me to be workable and I hope give
good results. In the determination of heroine in heroine tablets it would appear that
if morphine were present from the decomposition of the tablet some of it would be
extracted by the method proposed and estimated as heroine.
William Rabak.—The figures represent results obtained by the direct titration of
extracted alkaloids with 0.02N sulfuric acid solution without the use of 0.02N alkali.
The methods which you submitted I found to be excellent in every detail.
De eee ee
J. Assoc. Official Agr. Chemists, 1921, 5: 150.
574 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Results of analysis of alkaloids of opium.
SAMPLE DRUG RABAK MCCAUS- | GLYCART EATON
NO LAND
percent | percent per cent per cent
1 Morphine hydrochloride, U.S. P....| 98.64 97.70 98.34 | 102.40
98.06 97.89* | 97.80 | 101.90
2 Codeine sulfate, U.S. P............ 103.84 | 104.40 | 104.90 | 104.10
103.23 | 104.20 | 104.90 | 104.10
cimshoyensrs Mall ebearees ote 104.10: |) Saree
3 Diacetylmorphine hydrochloride, 98.14 | 100.34 99.82 | 100.70
LUPISH| LAARRe Beis At - 8 Seguro 98.14 99.95 99.73 | 100.70
4 Powdered morphine sulfate tablets..| 24.28 24.47 24.83 25.60
24.28 24.02 24.61 25.60
5 Powdered codeine phosphate tablets.| 49.13 50.76 50.10 51.40
48.84 50.00 49.94 51.09
6 Powdered diacetylmorphine tablets. 12.63 13.35 13.06 13.20
12.54 13.28 12.89 13.30
* Check obtained by determination of chloride content.
H. McCausland.—
Morphine: The alkaloidal residue was treated with 2 cc. of methyl alcohol (commercial
sample of highest purity), covered with a watch glass and heated, excess 0.02N
sulfuric acid added, diluted with 50 cc. of water and titrated back with 0.02N sodium
hydroxide.
Codeine: The residue was dissolved in a similar manner and titrated directly with
0.02N sulfuric acid.
Heroine: The residue was dissolved in a similar manner and titrated directly with
0.02N sulfuric acid.
Codeine and heroine: Used 20, 15, 10, 10 and 5 cc. of chloroform. Final chloroform
washings after washing filtered through 7 cm. filter paper wet with chloroform. Neu-
tral to litmus.
A uniform standardization of 0.02N sulfuric acid is suggested by dissolving about
150 milligrams of anhydrous brucine in 2 cc. of methyl alcohol and titrating directly.
Brucine should be dried at 100°C. M. P. should be 178°C.
For this work, the salts of the alkaloids were selected from the prep-
arations which are believed to be the most stable. In general, the
United States Pharmacopoeia has no assay for the salts of the alkaloids
of opium. Analysis of several samples, purchased on the market,
showed a variable content of crystal water; consequently the results
reported were not expected to give a working control of 100 per cent.
The work as a whole shows that the methods are more satisfactory
than those used at the present time. The results obtained are quite
satisfactory, and the following recommendations are therefore sub-
mitted:
1922] FULLER: LAXATIVE AND BITTER TONIC DRUGS 575
RECOMMENDATIONS.
It is recommended—
(1) That the qualitative and quantitative methods for the examina-
tion of morphine, codeine and diacetylmorphine, submitted at the last
meeting, be adopted by the association as tentative methods.
(2) That these methods be further studied with the view of making
them official.
REPORT ON LAXATIVE AND BITTER TONIC DRUGS.
By Henry C. Futrer (Institute of Industrial Research, Washington,
D. C.), Associate Referee.
The work undertaken involved—
(1) The evolution of a method for assaying the anthraquinone drugs—
cascara, rhubarb, senna and buckthorn—and their fluid extracts.
(2) The evolution of a method for assaying aloes and the adaptation
of the same to preparations in which the laxative and bitter properties
are characterized by aloes and aloin.
Specifications were drawn up for a method for assaying the anthra-
quinone drugs and submitted to a list of collaborators with carefully
selected samples of powdered rhubarb, powdered senna and U. S. P.
fluidextracts prepared from the same drugs.
Method I.—Assay of Rhubarb, Senna and Cascara.
(Use 2 grams of rhubarb, 5 grams of senna and 5 grams of cascara.)
Place sample in an Erlenmeyer flask, add 200 ce. of dry chloroform, attach to a
reflux condenser using a cork stopper covered with tin foil, boil 15 minutes and then
cool. Filter into a separatory funnel, washing with several successive portions (3
probably enough) of 40 cc. each of chloroform. Preserve the drug and filter for later
treatment.
Add 50 cc. of 5% sodium hydroxide to the chloroform in the separatory funnel,
shake thoroughly, let settle and draw off the chloroform layer into a clean separatory
funnel. Repeat the extraction with 5% sodium hydroxide twice, using the same
amount as in the first extraction. Discard the chloroform, combine the alkali solu-
tions, add 15 cc. of ether, shake and let settle. Run off the alkaline solution and dis-
card the ether. Add a slight excess of hydrochloric acid to the alkaline solution and
shake out three times with 50 ce. of chloroform. Combine the chloroform extractions,
wash with water and filter the chloroform through cotton inserted in the stem of the
separator, into a tared dish. LEvaporate, cool, dry in desiccator and weigh. This is
the weight of the free oxymethylanthraquinones.
The powdered drug on the filter is then returned to the Erlenmeyer flask for the
next step.
Add 200 cc. of chloroform and 50 cc. of 25% sulfuric acid. Boil for 2} hours under a
reflux. At the end of that time, transfer the contents of the flask to a separatory fun-
nel, washing out the flask with a litile fresh chloroform into the separatory funnel.
Discard the acid. Add 50 cc. of 10% sodium bisulfite solution, shake thoroughly,
let settle and draw off the sodium bisulfite. Add 100 cc. of 1% hydrochloric acid,
[Vol. V, No. 4
576 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
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1922] FULLER: LAXATIVE AND BITTER TONIC DRUGS 577
shake, let settle and draw off the acid. Then wash with 100 cc. of water, let settle
and filter the chloroform, through cotton inserted in the stem of the funnel, into a
distilling flask. Recover a portion of the solvent, pour into a tared dish, evaporate,
dry in desiccator and weigh. Report percentage of free oxymethylanthraquinones and
combined oxymethylanthraquinones.
For the fluidextract take a 5 cc. sample, spread on 5 grams of pure sawdust and
evaporate on a steam bath. Transfer the dry sawdust to an Erlenmeyer flask and pro-
ceed with the determinations precisely as in the case of the powdered drug.
SUGGESTIONS OF COLLABORATORS.
(1) According to the directions a large quantity of chloroform is required. If
practicable, it would seem desirable to reduce the quantity of chloroform.
(2) In the assay of the fluidextracts it was found that some of the dried sawdust
together with the material could not be removed completely from the dish by washing
with chloroform, whereas a little 25% acid readily aided in the transfer.
(3) The results of analysis of the samples appear to Le very satisfactory and the
method gives much promise. If it is found by other collaborators to be satisfactory,
it will prove very valuable in the examination of the class of products for which it is
intended.
DISCUSSION.
The results obtained by the collaborators are very encouraging to one
who has had previous experience as a referee in cooperative analytical
work. The novelty of the method and the fact that most of the col-
laborators were unable to make more than a single run on the samples
submitted would lead one to anticipate much wider divergencies from
the average figures than are reported. The details of new methods
always require considerable polishing, and this is best accomplished by
studying the comments of the collaborators and embodying their sug-
gestions in the directions that are finally submitted for adoption. In
this work the summations of the total anthraquinone derivatives in
their general relation to the results obtained on the individual drugs are
especially encouraging because they correspond very well with data in
the literature on the subject. The results indicate that, with proper
manipulation, a chemist will be able to satisfy himself concerning the
quality of the bitter laxative drugs of the anthraquinone type, and that
he can go a long way in estimating the quantity present in a mixture.
It is interesting to note that the incorporation of these drugs into fluid-
extracts results in a considerable loss of anthraquinone derivatives.
At the time this work was being conducted your referee instituted
some experiments on a colorimetric method based upon the hydrolysis
of the anthraglucosides and the subsequent extraction of the oxymethyl-
anthraquinones by ether which had been tested at the laboratory of
the Bureau of Internal Revenue. The method as used in this labora-
tory is as follows:
578 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Method II.—Colorimetric Valuation of Rhubarb, Cascara and other
Anthraquinone Drugs.
Heat 0.5-2 grams of the finely powdered drug for 15 minutes with 50 ce. of 5%
sulfuric acid under a reflux condenser. After cooling, extract the mixture with suc-
cessive quantitites of ether until that solvent remains colorless when treated with a
trace of potassium hydroxide. Heat the separated aqueous liquid to expel dissolved
ether, boil for 15 minutes longer and again extract with successive quantities of ether.
When no more soluble matter can be removed, shake the combined ethereal extracts
with 200 cc. of a 5% solution of potassium hydroxide, in successive portions, until
the alkaline liquid is no longer red. Dilute the red solution to 500 cc. with distilled
water and transfer an aliquot of 10 cc. or more (depending on the depth of color of
the liquid in the flask) to a Nessler tube, dilute to 50 cc. with distilled water and match
against an alkaline aloe-emodin solution of the strength of 1-1,000,000.
This procedure was modified by comparing the color with an alkaline
solution of the anthraquinone principles extracted from a good average
sample of the drug under consideration. This should always be done
when estimating the quantity present in a liquid preparation.
As an example of how this works out, a residue representing the free
and combined anthraquinones from 2 grams of cascara was dissolved
in 10 cc. of 10 per cent potassium hydroxide and the solution was made
up to 100 cc. in a volumetric flask. Each cc. represented practically
0.3 grain of cascara. It was found that 2 cc. of this solution diluted to
50 cc. in a Nessler tube matched 10 ce. of a solution of the same charac-
ter obtained from a product under review. In other words, 1 ounce or
30 cc. contained about 1.8 grains of cascara as determined by the recog-
nizable principles.
ALOES AND ALOIN.
An investigation of aloes and aloin was conducted conjointly with the
work on rhubarb, senna and cascara.
Aloin is a peculiar substance differing from the anthraquinone bodies,
being comparatively insoluble in the organic solvents. The readiness
with which the anthraquinone derivatives dissolve in chloroform facili-
tated the development of a method for determining them.
Aloin readily combines with bromine. It was thought at first that a
method of identification and possibly of estimation might be worked out
based on this property, and it was found that in the case of pure aloin
the figures obtained were fairly satisfactory. But when aloin occurred
in admixture with other drugs the results were not reliable.
Aloin in solution apparently disappears rapidly if the liquid is left
open to the air for any length of time. Just what happens to the sub-
stance is not known with certainty, but it is a fact that a solution of
aloin which may be noticeably bitter at a dilution of 1 to 2,000 will,
in a month’s time, if open to the air or if enclosed in a bottle with con-
siderable air standing over the surface of the liquid, become so reduced
in its bitter manifestation that it may show bitterness at a dilution no
1922| FULLER: LAXATIVE AND BITTER TONIC DRUGS 579
greater than 1 to 15. The loss which aloin undergoes under these con-
ditions is confirmed by the bromine test noted previously, but the
reaction is not sufficiently reliable to render it useful in quantitative
work.
A method for determining the comparative bitterness of aloin solu-
tions and thereby obtaining an approximate idea of the quantity present
and the probable therapeutic effect was worked out in this laboratory.
This method, submitted with samples to the collaborators for study
with the rhubarb and senna samples, is as follows:
Method III.—Determination of Degree of Bitterness of Aloes Mizture.
Measure carefully 5 cc. of the liquid and introduce into a 100 ce. graduated cylinder.
Dilute to 100 cc. and mix. Designate as Solution No. 1.
Take 5 cc. of this mixture, carefully measured, introduce into a 100 cc. graduated
cylinder, dilute to 100 cc. and mix. Designate as Solution No. 2.
Introduce 5-10 cc. of Solution No. 2 into the mouth, allowing it to reach the anterior
portion, and note whether or not there is any bitter taste.
If bitter, take 5 cc. of Solution No. 2, dilute to 100 cc. and test for bitterness. If
this mixture is not bitter, make up further mixtures using 5 cc. of Solution No. 2
and gradually diminish the quantity of water. Note the dilution at which the last
sensation of bitterness is apparent and then, based on the volume of the original mix-
ture, figure the degree of dilution necessary to bring about the loss of bitterness.
DISCUSSION.
The reports from the collaborators on this test were not very satis-
factory and as the length of time the samples stood before the tests
were made is uncertain, no figures will be submitted.
Finding it inadvisable to experiment further with the use of bromine
as a reacting agent for estimating aloin, the study turned to a survey of
the decomposition products which were obtained when aloin was subjected
to the action of boiling acids and alkalis. Without going into detail as
to the results of the numerous experiments conducted, it was finally
ascertained that when boiled with sulfuric acid aloin was hydrolyzed,
and one of the products of decomposition reacted with a derivative of
paranitraniline forming a product very insoluble in water, and which
was produced in constant quantity, relative to the amount of aloin
originally in solution. As a result of this discovery it was believed that
the way was opened for the development of a quantitative method for
estimating aloin.
A series of tests was conducted in order to work out the proper con-
ditions for running the method. As a result a set of specifications was
evolved, which will be submitted to the collaborative chemists for their
study. The method can be adapted to any kind of pharmaceutical
preparation featuring aloes or aloin. The two procedures detailed
below are the first of their kind ever proposed along these lines.
580 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Method IV.—Aloin Assay.
Weigh out 0.2 gram of aloin into a 200 cc. Erlenmeyer flask fitted with stopper and
attached to a reflux. Add 100 cc. of 25% sulfuric acid and boil 1 hour under the reflux.
Cool in an ice mixture, dilute if necessary and add a slight excess of concentrated
sodium hydroxide solution followed by 50 cc. of diazotized paranitraniline solution
(1). Add hydrochloric acid until precipitation is complete and heat on a steam bath
until it agglomerates. Filter on a creased filter paper, wash with water and pour
hot C. P. acetone onto the precipitate, collecting the filtrate in a tared dish and adding
sufficient acetone to take up all of the diazotized precipitate. Evaporate the acetone
and dry residue at not over 100°C. Report weight of product.
Aloins probably vary to some extent in their constitution or at least in their charac-
ter as articles of commerce. 0.2 gram of good commercial aloin gives a precipitate
with the diazotized paranitraniline reagent, amounting to about 0.4861 gram.
(1) Treat 7 grams of paranitraniline with 12 grams of concentrated hydrochloric
acid and 50 cc. of water and boil until solution is effected. Cool. Add 3.7 grams of
sodium nitrite in 15 cc. of water. Cool. Dilute to 500 ce.
Method. V.—Eslimation of Aloin in Liquid and Solid Medicines.
For assaying aloes or mixtures containing aloes or aloin the procedure will depend
somewhat on the composition of the preparation. For a pill, tablet or any other
galenical in solid form, a carefully comminuted sample should be thoroughly extracted
with 95% alcohol. The mixture of alcohol and sample may, if desired, be put directly
into a graduated flask and made up to the mark with 95% alcohol. In the case of
pills or tablets, take 100 units and have the final solution made up to 500 ce.
If the sample is a liquid take a portion of reasonable quantity, say 25-50 cc., and
having ascertained the weight, make up to 500 cc. with alcohol.
Of the solution in the 500 cc. graduated (volumetric) flask take an aliquot of 100 ec.
of clear liquor and allow the alcohol to evaporate spontaneously, but better in a vacuum
in order to lessen the time of exposure to outside influences. The residue should
be under 100 ce.
Take up with water and transfer to a 100 cc. volumetric flask. (If aloes are under
investigation take 10 grams; introduce directly into 100 cc. volumetric flask and add
50 ec. of water.) When all the aloin is in solution proceed as follows: Add lead acetate
solution until in excess. Then make up to volume with water. Filter off an aliquot
of 50 cc., transfer to a 100 cc. volumetric flask, add potassium oxalate crystals or solu-
tion in sufficient quantity to get rid of the excess of lead and make up to the mark.
Filter off a 50 ce. aliquot, transfer to hydrolyzing flask, add 100 ce. of 25% sulfuric
acid and heat under a reflux for 1 hour. Cool, transfer to separator and shake out
with chloroform to remoye any anthraquinone derivatives. Draw off the acid liquor
into an evaporating dish and remove the chloroform at the temperature of the water
bath. Return the liquor to a beaker or Erlenmeyer flask, add an excess of sodium
hydroxide and precipitate with diazotized paranitraniline precisely as described in the
aloin assay. Finish determination in the same way.
In cases where even the approximate quantity of aloes is not known,
it is suggested that the liquid, after removing the chloroform, be trans-
ferred to a volumetric flask of 500 ce. capacity and made up to the mark.
Then aliquots of 50-100-250 cc. may be taken for treatment with the
diazotized paranitraniline.
—-
1922] PAUL: REPORT ON ACETYLSALICYLIC ACID 581
RECOMMENDATIONS.
It is recommended—
(1) That the gravimetric method evolved for assaying the anthra-
quinone drugs be given a more exhaustive study during the ensuing
year.
(2) That conjointly with the study of the gravimetric assay the
collaborative work be extended to the colorimetric determinations.
(3) That the method for estimating aloin be submitted to the asso-
ciation for study and criticism.
No report on the determination of calomel, mercuric chloride and
mercuric iodide in tablets was made by the associate referee.
REPORT ON ACETYLSALICYLIC ACID.
By Artuur E. Pau (U. S. Food and Drug Inspection Station, 411
Government Building, Cincinnati, Ohio), Associate Referee.
Methods for the determination of aspirin must produce the separation
of the aspirin from other substances which may be present, or be of such
nature that foreign substances will not interfere. However, it would
seem that it is necessary, first, to establish satisfactory methods for the
determination of the product in question, without any special reference
to possible interferences.
In the process of the spontaneous decomposition of aspirin, there is
formed not only salicylic acid but also free acetic acid, and it would,
manifestly, be of considerable interest to be able to determine this
decomposition product. However, no entirely satisfactory method has
as yet been devised. The only published method is that by A. Nutter
Smith!. This method is correct in principle but somewhat cumbersome
and unwieldly of execution. Copies of the method were submitted to
collaborators for consideration with a view to making such changes or
modifications as would result in a satisfactory procedure. No reports
were received.
As it was believed impracticable to secure tablets of absolutely known
composition and uniformity three samples in powder form, prepared
from a well-known commercial make, were sent to collaborators. These
were designated Sample No. 1, Sample No. 2 and Sample No. 3, and
their composition was as follows:
per cent
Sample No. 1.—Commercial aspirin. ..........----+--0+++++ 99.75
Salicylictacid wie eee. Aes? Sonus Ae Bik SSF 0.25
Sample No. 2.—Commercial aspirin.........-.-.-------+-+- 100.00
Sample No. 3.—Commercial aspirin. .......--------+++++++> 80.00
Milkesugaree seven see sole er reicret ao: 20.00
1 Pharm. J., 1920, 105: 90.
582 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Collaborators were advised as to the general composition of the
samples and that the preliminary extraction with chloroform might be
omitted in working with Samples Nos. 1 and 2, but that Sample No. 3
would require the complete examination as prescribed.
METHODS.
The following seven methods were submitted for study:
I.—Melting Point.
If excipients are present, treat 0.2-0.3 gram with small portions of chloroform and
filter into a beaker or dish. Evaporate the bulk of the chloroform on the steam bath
and complete by spontaneous evaporation until thoroughly dry. Determine the
melting point as directed in the U. S. Pharmacopeeia!.
II. —Qualitative test for free salicylic acid*.
Shake a 0.5 gram sample into a small Erlenmeyer flask with about 10 cc. of chloro-
form and filter. LEvaporate, dissolve the dry residue in 10 cc. of cold water and filter.
Add 1 drop of ferric chloride solution. (This should not produce more than a very
faint violet color.)
ITI.—Quantitative method for free salicylic acid.
(B. P. method, modified by P. N. Leach, Jr.? and by the associate referee.)
Prepare a standard salicylate solution as follows: Dissolve 0.1 gram of pure salicylic
acid in 5 ce. of alcohol and dilute with distilled water to 1000 cc. Prepare also a 1%
aqueous solution of iron alum (ferric ammonium sulfate).
In a Schreiner colorimetric tube dissolve a 0.2 gram sample in 1 cc. of alcohol and
add 48 cc. of water. Filter if necessary. In a second colorimetric tube place 5 ce. of
the standard salicylic acid solution, 1 cc. of alcohol, 1 drop of acetic acid, and dilute as
above. Now add 1 cc. of the iron solution to each tube. Let stand 5 minutes and
compare the colors in the colorimeter.
IV.—Iodine method for total salicylates.
Heat a 0.1 gram sample in a 200 ce. Erlenmeyer flask with 20 cc. of water and 1 gram
of sodium carbonate on a steam bath for 15 minutes. Filter if necessary to remove
talc. Dilute to 100 cc., heat nearly to boiling, then add slowly 25-40 cc. of strong
(about 0.2N) iodine solution, and proceed as directed for sodium salicylate‘. Multi-
ply the weight of the precipitate by 0.4016 to obtain the total salicylic acid and deduct
the free salicylic acid previously determined. The difference represents the combined
salicylic acid. Multiply by 1.304 to obtain the weight of aspirin.
V.—Bromine method for lotal salicylates by Koppeschaar reagent.
Prepare 0.1N bromine solution as described in the U. S. Pharmacopeoeia®,
Saponify a 0.5 gram sample with 10 ec. of 2% sodium hydroxide solution by heating
for 15 minutes on a steam bath. Dilute with water in a measuring flask to 500 ce.
Transfer an aliquot portion of this solution, containing not less than 0.040 gram nor
U.S. Pharmacoporia, IX, 1916, 596.
* Allen's Commercial Organic Analysis, 4th ed., 504.
1J. Ind. Eng. Chem., 1918, 10: 288.
* Assoc. Official Agr. Chemists, Methods, 1920, 298.
* U.S. Pharmacopoeia, IX, 1920, 558.
1922) PAUL: REPORT ON ACETYLSALICYLIC ACID 583
more than 0.050 gram of acetylsalicylic acid, to a 500 cc. glass-stoppered Erlenmeyer
flask, add 30 cc. of the 0.1N bromine solution and 5 cc. of strong hydrochloric acid,
and immediately insert the stopper. Shake repeatedly half an hour and allow to stand
for 15 minutes. Remove the stopper just sufficiently to introduce quickly 5 ce. of
20% potassium iodide solution, taking care that no bromine vapors escape, and im-
mediately stopper the flask. Shake thoroughly, remove the stopper and rinse it and
the neck of the flask with a little distilled water so that the washings may flow into the
flask. Titrate with 0.1N sodium thiosulfate solution, using starch as the indicator.
Each cc. of 0.1N bromine corresponds to 0.002301 gram of salicylic acid, or to 0.003001
gram of acetylsalicylic acid.
VI.—Double titration method for acetylsalicylic acid’.
If excipients are present, treat about 0.3 gram, accurately weighed, with small por-
tions of chloroform; filter into a beaker and wash until completely extracted. Evapo-
rate the bulk of the chloroform on the steam bath, finishing with the aid of an electric
fan without heat. Dissolve the chloroform-soluble residue in 10 cc. of alcohol.
If excipients are absent, dissolve the sample directly in the alcohol.
Titrate immediately with 0.1N alkali, using phenolphthalein as an indicator. (This
titration should be made rapidly, and the first persistent pink color used as the end
point, since any slight excess of alkali has a tendency to hydrolize the ester quickly.)
Add a volume of 0.1N alkali equal to that used in the first titration and then an
excess of 5 cc. Heat on the water bath for 15 minutes. Titrate back with 0.1N acid.
If the product is pure, the total amount of alkali consumed will be twice that of the
first titration. Each cc. of 0.1N alkali consumed in the two titrations is equivalent to
0.009 gram of acetylsalicylic acid.
VII.—Free acelic acid.
The method submitted was that given by Smith in his paper, ‘““A Method for the
Determination of Free Acetic Acid Present in Acetyl-Salicylic Acid (Aspirin)’**.
The collaborators reporting were the following: C. K. Glycart, A. W. Hanson and
H. O. Moraw, U. S. Food and Drug Inspection Station, Chicago, Ill.; and William
Rabak, U. S. Food and Drug Inspection Station, Minneapolis, Minn.
COMMENTS BY COLLABORATORS.
A. W. Hanson.—No trouble was experienced with any of these methods for aspirin.
The bromine titration method is believed to be the quickest and most satisfactory for
total salicylates where a number of determinations are to be made.
C. K. Glycart-—The melting points of the samples of aspirin appear to be lower than
found in the literature. The qualitative and the quantitative methods readily show
the presence of free salicylic acid. The iodine and bromine methods and particularly
the double titration method promise to be satisfactory in the valuation of aspirin
preparations.
H. 0. Moraw.—I: In the sample containing excipients, the residue from the chloro-
form extract was not sufficiently dry to pour into the capillary tube without previous
drying. Dried it between filter papers. III: The chemical name for iron alum should
be given either alone or in parentheses. In the second paragraph, the directions for
diluting would be clearer if changed to read “‘and 43 cc. of water” or “and dilute to
same volume as above’. (This refers to the tube containing the standard.)
1 Pharm. Zig., 1913, 58: 26.
? Pharm. J., 1920, 105: 90.
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1922] PAUL: REPORT ON ACETYLSALICYLIC ACID 585
DISCUSSION.
The comments by Moraw are quite valuable, since they indicate the
points in the methods as submitted which are not entirely clear. The
details suggested may be incorporated into the methods without con-
stituting any real change therein, and it is thought that they will render
the methods more easily understood by an analyst who undertakes to
use them for the first time.
CONCLUSION.
The results reported on the melting point vary considerably, but as a
whole agree very well with those of Leach, who made a rather extensive
study of the melting point of this substance. His conclusion is that
purified acetylsalicylic acid melts at about 132°C. and that various
commercial brands melt between 128° and 133°C. Sharp readings
can hardly be expected since aspirin is a condensation product which
readily undergoes decomposition, particularly at elevated temperatures,
and becomes quite unstable at or near its melting point.
Reference is usually made in the literature to the melting point of
aspirin, and since the results obtainable are sufficiently close to be of
some value in the examination of samples, the official methods might
well include details for this determination. This would seem particu-
larly necessary since a deviation from a definite set of details would
probably result in a still greater divergence in results.
The qualitative test for free salicylic acid, as might be expected, is
entirely satisfactory.
The correct quantitative results for the samples submitted for free
salicylic acid are not known as it was not possible to secure a sample
which gave entirely negative tests. But it will be observed that the
results obtained on Sample No. 1 (aspirin with 0.25% salicylic acid
added), after deducting the free salicylic acid found in the aspirin used
(Sample No. 2), are quite acceptable. The differences represent the
percentages of added salicylic acid, according to the results reported by
each collaborator, and are as follows:
per cent
CMON GL VCArty Soule ecient leas tay: ye Eee 0.29
IMU PRELanSOMUTe tee te ete a nein gecenttar sit 0.30
AViillicamnpbvalia komen ete ee eae cn citaceseeegte enews coisas score 0.29
LEFT COV TAM Keates gk a rs a trp 0.30
(Actually added, 0.25 per cent.)
The results obtained in the determination of total salicylic acid by
both the gravimetric and volumetric methods were quite satisfactory.
The double titration method is the simplest and quickest for evaluating
a sample, and it is the most satisfactory method when working with
tablets known to contain only pure aspirin and the ordinary excipients.
586 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No, 4
It must be remembered, however, that this method is not specifically
for aspirin, and that it does not differentiate between this product and
other similar substances. It is therefore necessary, in working on
unknown samples, to supplement the double titration results by such
determinations as are included in this report, which are more specific.
It is believed that if all the methods given in this report are applied to
a sample, the results will show quite satisfactorily the proportion of
aspirin present, provided that the figures are consistent. It is not
believed, however, that the methods are sufficient in all possible sorts
of mixtures.
RECOMMENDATIONS.
It is recommended—
(1) That the method for the determination of the melting point as
given in this report be adopted by this association as a tentative method.
(2) That the qualitative test for free salicylic acid, as given in this
report, be adopted as a tentative method.
(3) That the quantitative method for salicylic acid, substantially as
given in this report but including the details suggested by H. O. Moraw,
be made a tentative method, and that it be resubmitted to collaborators
by next year’s associate referee with a view to its adoption as an official
method.
(4) That the iodine method for total salicylates, as given in this
report, be made a tentative method, and that it be further tried out by
next year’s associate referee with a view to its final adoption as an
official method.
(5) That the bromine method for total salicylates, as given in this
report, be made a tentative method, and that it be further tried out
by next year’s associate referee with a view to its final adoption as an
official method.
(6) That the double titration method for acetylsalicylic acid, as given
in this report, be made a tentative method, and that it be further tried
out by next year’s associate referee with a view to its final adoption as
an official method.
(7) That A. Nutter Smith’s method for free acetic acid, and any
other available methods for this determination, be submitted to col-
laborative study by next year’s associate referee. :
(8) That consideration be given to methods for the quantitative
determination of combined acetic acid in acetylsalicylic acid.
(9) That the problem of determining aspirin in the presence of pos-
sible interfering substances be given consideration by next year’s asso-
ciate referee.
No report on methods for the examination of phenolphthalein was
made by the associate referee.
1922] WRIGHT: DETERMINATION OF CAMPHOR IN TABLETS 587
REPORT ON METHODS FOR THE DETERMINATION OF
MONOBROMATED CAMPHOR IN TABLETS.
By C. D. Wricut (Bureau of Chemistry, Washington, D. C.), Associate
Referee.
In accordance with the recommendations of last year, cooperative
samples were prepared from two varieties of tablets purchased in the
open market and distributed to eight collaborators, together with copies
of two methods of determination essentially as published by W. O.
Emery! and E. O. Eaton’.
The methods follow:
Method I.
When an aqueous alcoholic solution of monobromated camphor is subjected to the
action of sodium amalgam, on heating, among other changes the bromine is split off
quantitatively in the form of its sodium salt, which may then be determined gravi-
metrically in the usual way.
REAGENT.
Sodium Amalgam.—To 100 grams of pure mercury which has been slightly warmed,
contained in a small porcelain mortar, add about 1 gram of bright metallic sodium,
cut in several pieces, by impaling the pieces successively on the point of a file and
holding submerged in the mercury until the reaction, which is rather violent, is com-
plete. Keep the resulting 1% amalgam in a tightly corked bottle.
DETERMINATION.
Count and weigh a suitable number of tablets to ascertain the average weight; reduce
to a fine powder and keep tightly stoppered. Weigh out a portion corresponding to
0.1 to 0.2 gram of monobromated camphor, and transfer quantitatively with 20 cc.
of alcohol and 10 cc. of water, to a small (100 cc.) round-bottomed flask, containing
15 grams of 1% sodium amalgam. Connect the flask, by means of a rubber stopper,
with a vertical reflux. Heat the mixture over a wire gauze just to boiling for a period
of not less than 30 minutes. After cooling slightly, wash out the condenser tube first
with 5 cc. of alcohol, then with 5 cc. of water, receiving the washings in the flask below.
Remove the flask to the steam bath and heat for another hour, or until the evolution
of hydrogen has nearly or quite ceased. Toward the latter part of this operation,
render the liquid about neutral with a few drops of acetic acid in order to further reduc-
tion. Transfer the contents of the flask to a separatory funnel, preferably of the
Squibb type, withdrawing and washing the mercury in A second separatory funnel
with at least two 50 cc. portions of water. Pass the several aqueous solutions quanti-
tatively through a small filter, collecting the clear filtrate in a suitable beaker. Pre-
cipitate with silver nitrate after the addition of about 5 cc. of nitric acid, and proceed
with the determination of the resulting silver bromide in the usual gravimetric way,
employing, if available, a Gooch crucible in the operation of filtering. The weight of
silver bromide multiplied by the factor 1.23 will give the quantity of monobromated
camphor originally present in the portion taken for analysis. A control should be
run on the amalgam in order to determine whether any correction is necessary for the
presence of halogen in material quautity.
1J. Ind. Eng. Chem.. 1921, 11: 756.
2 [bid., 1922, 14:
588 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
Method ITI.
Monobromated camphor is decomposed in hot alcoholic potash solution by the
addition of alcoholic silver nitrate solution and the resulting potassium bromide de-
termined as silver bromide.
PREPARATION OF SAMPLE.
Determine the average weight in the usual manner and grind to a fine powder. Keep
tightly stoppered.
DETERMINATIONS.
Weigh out in a small beaker an amount equivalent to about 0.2 gram of monobromated
camphor, add 25 cc. of alcohol, warm on the steam bath and filter into a flask (pre-
ferably about 250 cc. and provided with a ground-in condenser), washing both beaker
and filter with warm alcohol. Add 50 cc. U.S. P. normal alcoholic potassium hydroxide
and 25 cc. of alcoholic silver nitrate (0.2 gram in 50 cc. of alcohol) and connect with a
reflux condenser. Boil gently 1} hours, adding at intervals through the condenser
the remaining 25 cc. of the alcoholic silver nitrate solution. Cool, disconnect, and
transfer the contents to a large evaporating dish. Dilute to 200 cc. and decant into
a beaker, washing the sediment with water by decantation. Boil the solution 5 minutes
with 1 gram of zinc dust to clarify; filter into another beaker, washing thoroughly with
water, and add dilute nitric acid to decided acidity and aqueous silver nitrate solution
to complete precipitation. When the silver bromide has agglutinated, filter on a
weighed Gooch, wash with water and alcohol, dry at 100°C. and weigh. (The factor
for monobromated camphor is 1.23.)
Four reports were received and the results are tabulated below:
Results of determinations for monobromated camphor.
SAMPLE 1 SAMPLE 2
ANALYST
Method 1 | Method II) Method I | Method IT
per cent per cent per cent per cent
E. O. Eaton, U. S. Food and Drug In- 76.9 75.6 18.0
spection Station, San Francisco, Calif. 78.1 76.5 18.0
A. W. Hanson, U. 8. Food and Drug 75.9 75.0 17.0 17.3
Inspection Station, Chicago, Ill. 75.3 75.7 17.1 17.8
W. F. Kunke, Bureau of Chemistry, 75.0 73.2 17.0 18.7
Washington, D. C. 74.5 72.2 16.9 18.1
tin 74.7 at eR
74.4 Pes ot
C. D. Wright. 73.4 75.2 17.7 18.4
74.7 76.7 17.7 16.5
24 RIE 17.0
16.3
ANGLARC? 20). anise nae shoes 75.5 74.9 17.4 17.5
COMMENTS.
The results, while not remarkably concordant, are perhaps sufficiently
representative to indicate the degree of variance to be expected in the
|
;
.
.
1922] HANSON: METHODS FOR THE EXAMINATION OF PROCAINE 589
hands of different analysts. In the case of Sample 1, a difference of
1% is produced by an error of 1 to 2 milligrams in the silver bromide
weighed; with Sample 2 an error of 8 milligrams is required to produce
the same difference. Sample 2, however, contained vegetable extrac-
tives, and it is suggested that a final washing of the silver bromide with
alcohol would be especially desirable in this case, and would do no harm
in all cases as a precaution.
An evident omission in Method II is a caution to correct for the
halogen present in reagents by a blank determination. This is very
essential in view of the use of potassium hydroxide and of zine dust,
both of which commonly contain appreciable amounts of chloride.
In this connection it may be stated that equally good results were
obtained by Kunke and the writer by omitting the washing by decanta-
tion of the precipitated silver oxide in Method II, as well as the treat-
ment with zinc dust, and instead, after diluting the alcoholic solution in
the flask with water, filtering directly into a beaker and proceeding with
the precipitation by silver nitrate. Whether this could be safely done
in all cases is, however, a matter for further study.
RECOMMENDATIONS.
It is reeommended—
(1) That Methods I and II for the determination of monobromated
camphor in tablets be adopted as tentative.
(2) That further study be made of Method II with a view to its
possible simplification.
REPORT ON METHODS FOR THE EXAMINATION OF
PROCAINE (NOVOCAINE).
By Atrrep W. Hanson (U. S. Food and Drug Inspection Station,
Transportation Building, Chicago, IIl.), Associate Referee.
The method submitted last year for the examination of procaine was
studied further, as well as the extraction and titration of the procaine
base from an ammoniacal solution. Samples were sent to collaborators,
and the results have been tabulated in an endeavor to determine the
most satisfactory method. The results obtained from collaborators in
1920 showed that the bromide-bromate titration method gave good
results on samples ranging from 0.02 gram to 0.20 gram.
DESCRIPTION OF SAMPLES.
No. 1.—Contained 12.15 per cent of procaine, balance sodium chloride.
No. 2.—Contained 23.38 per cent of procaine, 0.28 per cent of ad-
renalin, balance sodium chloride.
590 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
No. 3.—Consisted of commercial procaine tablets, powdered. Each
tablet was labeled as containing 0.02 gram of procaine and 0.00002 gram
of adrenalin, balance sodium chloride. Amount of procaine, calcu-
lated 58.8 per cent.
No. 4.—Consisted of procaine.
The procaine used in the mixtures was the same as Sample No. 4.
Sodium chloride was added to the first two samples as that is the sub-
stance used in commercial tablets.
The qualitative tests and the bromide-bromate quantitative method
(designated Method I in this report), submitted to the collaborators,
were essentially the same as given in last year’s report?.
Qualitative methods.
REAGENTS.
(a) Mercuric potassium iodide (Mayer’s reagent).—Dissolve 1.3 grams of mercuric
chloride in 60 cc. of water, add 5 grams of potassium iodide dissolved in 10 cc. of water
and make to 100 ce.
(b) Potassium permanganate solution.—Dissolve 5 grams of potassium permanga-
nate in water and make to 100 ce.
QUALITATIVE TESTS.
(1) Dissolve 0.1 gram of procaine in about 10 cc. of water. Add 2 ce. of potassium
permanganate solution. Warm if necessary. Reduction occurs with evolution of gas
having the odor of acetaldehyde. (Distinction from cocaine, which does not readily
reduce potassium permanganate.)
(2) Dissolve about 5 mgs. of procaine in 3 cc. of water and add a few drops of mer-
curic potassium iodide (a). In the case of procaine, a white precipitate is formed
which dissolves if a few cc. of dilute sulfuric acid (2%) are added. (The precipitates
with mercuric potassium iodide formed with stobaine and cocaine are not readily
soluble in dilute sulfuric acid.
(3) Dissolve about 0.1 gram of procaine in 2 cc. of water. Add 25 ce. of 0.1N sodium
hydroxide. (A white precipitate is formed which dissolves in excess of sodium hydroxide
when heated on a steam bath.) The alkali should be added from a buret. Heat the
solution for 25 minutes on a steam bath. Upon cooling the solution and extracting
with chloroform, no residue should be obtained upon evaporation of the chloroform.
(Stovaine does not readily hydrolize and a residue would remain upon evaporation of
chloroform, giving an alkaloidal reaction.)
(4) Dissolve 0.1 gram of noyocaine (procaine) in 5 ce. of water. Add 2 drops of
hydrochloric acid and 2 drops of sodium nitrite solution. Pour the mixture slowly
into 10 cc. of a solution of 0.2 gram of betanaphthol in 10% sodium hydroxide solu-
tion. A scarlet red precipitate is formed.
(5) Add 5 drops of potassium permanganate solution to 0.1 gram of novocaine in
5 ec. of water and 3 drops of hydrochloric acid. The violet color disappears imme-
diately (distinction from cocaine hydrochloride),
(6) Dissolve about 0.1 gram of procaine (noyocaine) in 1 cc. of sulfuric acid. The
solution remains colorless showing absence of organic impurities.
The following modifications may be noted:
In making the determination, it is advisable to run a control on 25 or
1 J. Assoc. Official Agr. Chemists, 1921, 5: 163.
1922| | HANSON: METHODS FOR THE EXAMINATION OF PROCAINE 591
50 cc. of the potassium bromide-bromate solution alongside and under
the same conditions as for unknown.
Results given under Method I modified were obtained by titration
of the extracted procaine base by the potassium bromide-bromate
method. The base was extracted from an ammoniacal solution accord-
ing to Method IJ. The oily residue, consisting of the procaine base,
was dissolved in 2 cc. of 95 per cent alcohol. A slight excess of 0.1N
hydrochloric acid was added and the alcohol removed by evaporating
almost to dryness on the steam bath. Method I‘ was followed from
this point commencing with the addition of an excess of 25 cc. 0.1N
sodium hydroxide and hydrolysis on the steam bath.
The proposed bromine titration method has the following advantages:
(1) Good end point.
(2) Very low 0.1N factor as compared with the 0.1N factor for acid titration, thus
enabling the determination of smaller amounts of the compound.
(3) The titration by this method can be performed on procaine direct without first
extracting the base as required by the other method. Procaine is sold in the form of
a powder or compressed into tablets with salt. It has been found that chlorides do
not interfere with this titration.
(4) The method is found to be rapid and accurate.
(5) The potassium bromide-bromate volumetric solution is stable.
(6) As cocaine and stovaine do not titrate by this method, it serves to differentiate
these substances from procaine.
In the case of tablets, it may be advisable to take enough to make a
representative sample and make up to a definite volume, using a volu-
metric flask. Aliquots of the clear solution can then be taken for the
quantitative determinations. Insoluble substances like starch and talc
can be removed in this manner.
II.—Gravimetric and Volumetric Method.
EXTRACTION AND TITRATION.
Weigh an amount of the powder or take enough tablets to equal about 0.2 gram of
procaine. Dissolve the sample in a few cc. of distilled water. Transfer the solution
to a separatory funnel and add about 3 cc. of ammonia. Extract the ammoniacal solu-
tion 4 or 5 times with chloroform. Use 15 cc. of chloroform for the first extraction and
10 ce. for the other extractions. Keep the volume of the aqueous solution small.
Filter and evaporate the chloroform extractions in a tared beaker. Evaporate the
chloroform by means of an electric fan, preferably at room temperature. Avoid pro-
longed heating of the procaine base, as it appears to be slightly volatile at 100°C.
Calculate the amount of procaine in the sample by multiplying the weight of extracted
residue by the factor 1.1546. Take up the residue with a slight excess of 0.1N or
0.02N acid. Titrate back the excess of acid with 0.02N sodium hydroxide and methyl
red indicator. The 0.1N factor for procaine hydrochloric is 0.027265.
The results of the determinations by the different methods using varying samples
obtained by the associate referee; H. McCausland, 4753 Ravenswood Ave., Chicago,
Ill., and J. H. Bornmann, 1625 Trausportation Bldg., Chicago, Ill., collaborators,
are shown in the following table:
aR ee eee
1 J. Assoc. Official Agr. Chemists, 1921, 5: 163.
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592 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS
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1922] | HANSON: METHODS FOR THE EXAMINATION OF PROCAINE 593
COMMENTS ON THE QUALITATIVE TESTS.
J. H. Bornmann:
Test No. 1.—Procaine reduces permanganate almost instantaneously, with the
formation of acetaldehyde, which may be recognized by odor.
Test No. 2.—Procaine yields a milky precipitate with Mayer’s reagent, which dis-
solves in a few cc. of 2% sulfuric acid. Cocaine yields a curdy precipitate and stovaine
a milky precipitate, neither of which dissolves in 2% sulfuric acid.
Test No. 3—This test was tried upon procaine, cocaine and stovaine. In no case
was a test obtained with Mayer’s reagent on the residue from extraction. Contrary
to the statement made in the outline, stovaine is hydrolized by this treatment.
Nore By REFEREE.—As originally written, the test was to be made on a 0.02 gram
sample. This sample was found too small, and the directions were changed to 0.1
gram. Stovaine gives a positive reaction if present in this amount.
Test No. 4.—Procaine yields a dark red precipitate and a dark red solution. In
the case of cocaine the precipifate is pale yellow, while the precipitate from stovaine
is bright yellow. In each case, the precipitate eventually dissolves, giving a red solu-
tion in the case of procaine and yellow in the case of cocaine and stovaine.
COMMENTS ON THE QUANTITATIVE METHOD.
J. H. Bornmann.—The results obtained by extraction and weighing appear to be too
high, while those obtained by acid titration of the extracted base appear to be too
low. The bromine titration method gives very good results considering the small
amount of material used, and where there are no foreign substances present to react
with the bromine, the determination is best made on the material direct without extrac-
tion.
H. McCausland.—The volumetric method using 0.02N sulfuric acid has been used
by the collaborator for two years, except that he dissolved the final residue in 2 cc.of
neutral alcohol, titrating directly with 0.02N sulfuric acid. If the amount exceeds
0.1 gram he prefers dissolving the base in an excess of 0.02N sulfuric acid and titrating
back with 0.02N sodium hydroxide. He states that he was not satisfied with the results
obtained by the bromide-bromate titration of procaine but, taken as a whole, the
results are very good.
DISCUSSION.
The results obtained by the different methods show that the bromide-
bromate method is the most accurate. (See results of analysis.) Where
small amounts of procaine are to be analyzed it is important to have a
solution with a small 0.1N factor and the bromide-bromate method
possesses this advantage. In titrating procaine base dissolved in alco-
hol with standard acid, using methyl red indicator, the end point is not
very sharp.
RECOMMENDATIONS.
It is recommended—
(1) That the qualitative tests and the bromide-bromate quantitative
method presented at the last meeting of the association, with the modi-
fication of the quantitative method referred to herein, be adopted as a
tentative method for the determination of procaine.
(2) That the method be studied during the next year with a view of
making it official.
594 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
PRELIMINARY REPORT ON METHODS FOR THE SEPARATION
AND ESTIMATION OF THE PRINCIPAL
CINCHONA ALKALOIDS.
By Exear O. Eaton (Food and Drug Inspection Station, U. S. Ap-
praiser’s Stores, San Francisco, Calif.), Associate Referee.
It first appeared possible to separate quinine from the other cinchona
alkaloids by the relative insolubility of its sulfate, as shown by Duncan’.
Considerable experimenting was done, using as a basis its precipitation
in a slightly ionized acid solution (dilute acetic acid) with excess sulfate
ions (addition of sodium sulfate). Analysis of the sulfate precipitate
by polariscopic methods showed that it contained other alkaloids,
notably cinchonidine.
Gustav Mossler? pointed out this difficulty, but the writer verified
it to his satisfaction. Mossler concluded that sulfate, chromate and
oxalate formed double salts with quinine and cinchonidine and that no
chemical separation of these two alkaloids on a scale suitable for assay
work was possible at present. Experiments verified this and it was
concluded, finally, that chemical separation of quinine and cinchonidine
on a small scale is not feasible.
The use of solvents as a means of separation was abandoned after
looking up the solubilities and trying a few experiments.
The idea of taking advantage of the methoxyl group in quinine as a
means of separating it from cinchonidine does not appear practicable as
a quantitative method.
After considerable work along these lines, experiments based upon
the separation of quinine and cinchonidine from other cinchona alka-
loids by their precipitation as tartrates (proposed by Koppeschaar,
1885) and their estimation in the combined precipitate by polariscopic
methods as suggested by Hesse*, Oudemanns‘, Lenz® and others appear
to be most promising and to give fairly accurate results if all conditions
are carefully controlled.
This experimental work was limited to quinine, cinchonidine and
cinchonine.
DETERMINATION.
Take sufficient sample to give approximately 0.3 gram of total alkaloids and dis-
solve in dilute sulfuric acid. Filter if necessary, make ammoniacal and extract with
chloroform to exhaustion; evaporate; dry at 110°C.; and weigh. Dissolve in 50 ce.
of reagent “N"’ (225 cc. of normal sulfuric acid diluted to 1000 cc.), heat on a steam
bath 10 minutes and make just alkaline with dilute sodium hydroxide solution; then
1 Pharm. J., 1909, 82: 429.
2 Pharm. Monalsch., 1920, 1: 2-7, 17-22.
2 Ann. Chem. (Liebig) 1875, 176: 203; 1876, 182: 128; 1880, 205: 217.
4 Tbid., 1876, 182: 33.
& Ztschr. Chem, 1888, 27: 549.
1922] EATON: SEPARATION OF PRINCIPAL CINCHONA ALKALOIDS 595
faintly acid, using dilute acetic and methyl red indicator. Add 25 cc. of saturated
Rochelle salt solution (neutralizing just before using with dilute acetic acid and
methyl red indicator); place in the ice-box, stirring occasionally for 2 hours. Filter
and wash with a cold, half-saturated, neutralized Rochelle salt solution, using a small
wash bottle and stirring precipitate on filter with a stirring rod to remove all akla-
loids. Save combined filtrate and washings (Solution “‘A’’) for determination of
cinchonine. (The tartrate precipitate will contain quinine and cinchonidine and is
designated as Group I.) Decompose the precipitate with dilute sulfuric acid and
transfer to a 250 cc. Squibb-type separatory funnel; wash the beaker and filter with
dilute acid, shaking out with 5 cc. of chloroform to remove the methyl red. Wash
the chloroform with 5 cc. of dilute acid, discard the chloroform and add the acid to
the first separatory funnel.. Make solution ammoniacal, shake out with four 20 cc.
portions of chloroform, evaporate in a tared beaker containing a few grains of sharp
sand, dry at 100°C. a few minutes, cool and weigh. Add 1 cc. of reagent ““N”’ for
each 0.015 gram of alkaloids, let stand 15 minutes, stir with policeman to complete
solution and transfer to a polariscopic tube, filtering if necessary. (If a saccharim-
eter is used, reading to only —20°V., it will be necessary to use a 100 mm. tube. If
an angular rotation instrument is available use a longer tube for greater accuracy.)
Take the reading in angular degrees at 20°C., using sodium light or a bichromate
filter with white light. If only a small amount of liquid is available an ordinary
polariscopic tube can still be used by decreasing its capacity by inserting a straight
thin-walled glass tube of 4 or 5 mm. internal diameter and about 5 mm. shorter than
the polariscopic tube. Round its edges slightly in a flame and fix rigidly in the ob-
servation tube, using a portion of a 1-hole rubber stopper in the enlarged end of the
tube and a bit of thin rubber tube at the smaller end. (These tubes can be readily
filled by means of a small funnel held close to the inner edge of the polariscope tube
at the smaller end, where the short inner tube leaves a small cup. The use of small-
bored inner tubing for polariscopic use was first brought to my attention in an un-
published article by A. G. Murray.)
Take half of the total solution, calculated from the amount of reagent “‘N’’ used
to dissolve Group I, and determine alkaloids by above shake-out method; evaporate
and dry at 110°C. for 2 hours; cool and weigh. (It appears that the alkaloids read
lower after drying at 110°C.)
Calculate the quinine and cinchonidine as follows:
(A) De (specific rotation), in which
a=observed degrees in angular rotation;
L=length of tube in mm.; and
c=grams of anhydrous alkaloids per 100 cc. as ascertained by shaking out and
weighing after polarization.
-
Now substitute the value of (A) 5. in the formula!
20
(A) J) —180
10074180 = Per cent of quinine in the total anhydrous alkaloids of Group I.
The total anhydrous alkaloids, i. e. twice the weight of anhydrous alkaloid found
minus the weight of quinine found equals the cinchonidine in Group I. Calculate the
percentage of each in the original mixture from the weight of the sample used.
Make solution ‘‘A’’ ammoniacal, shake out with four 20 cc. portions of chloroform,
1 Optical Rotation of Organic Substances. Landolt-Long, 1902, 500.
596 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
evaporate the solvent, dry at 110°C. for 2 hours and weigh. Dissolve in reagent
“N” (1 ce. for each 0.015 gram of alkaloid), polarize, and calculate the specific rota-
tion. In the absence of other cinchona alkaloids than quinine and cinchonidine, this
should correspond reasonably well with that of cinchonine if present in an essential
amount (-++ 260), since quinine and cinchonidine are but slightly soluble in the mens-
truum used to precipitate Group I.
If quinine, cinchonidine or cinchonine occur alone, it can be readily
estimated by simple extraction and determination of the specific rota-
tion in acid solution under conditions outlined previously.
Quinine sulfate after recrystallization four times in the laboratory
was found to give a specific rotation of -277.4. Specimens of cinchon-
idine sulfate and cinchonine sulfate, U. S. P. quality, showed respec-
tively specific rotations of —180 and +260, all calculated to anhydrous
alkaloids. This checks closely with the literature.
Solutions of these three alkaloidal salts were prepared to contain
0.015 gram of anhydrous alkaloids per cc. mixed in different proportions
and assayed by the above methods with the following results:
Recovery by proposed method.
QUININE CINCHONIDINE CINCHONINE
MIXTURE 5
Taken | Recovered} Taken | Recovered! Taken | Recovered
gram per cent gram per cent gram per cent
1 0.225 93.3 0.075 102.0 0.075 108.0
Z, 0.120 97.0 0.150 94.0 0.045 4
3 0.225 94.0 0.060 90.0 0.045 %
4 0.150 90.0 0.150 105.0 0.150 101.0
5 0.180 90.0 0.120 107.0 0.045 *
* Not determined.
This method appears to be promising for the analysis of mixtures of
these three alkaloids.
RECOMMENDATION.
It is recommended that the method outlined in this report for the
separation and estimation of the principal cinchona alkaloids and any
other methods that may be available be studied by the association during
the next year.
a me ee
1922] EATON: JAPANESE AND AMERICAN PEPPERMINT OILS 597
THE DIFFERENTIATION OF JAPANESE AND AMERICAN
PEPPERMINT OILS.
By Excar O. Eaton (Food and Drug Inspection Station, U. S. Ap-
praiser’s Stores, San Francisco, Calif.), Associate Referee.
Large quantities of Japanese oils, which are derived from Mentha
arvensis, are imported into this country. The United States Pharma-
copeeia recognizes peppermint oil for drug purposes as the volatile oil
from Mentha piperita and Circular 136! recognizes the same for food
purposes; consequently, it is obvious that from the standpoint of food
and drug inspection a means of differentiating these oils is desirable.
Much of this imported oil is dementholized, but its constants are still
very close to the United States Pharmacopceia article.
Several color tests have been proposed for the identification of pepper-
mint oil, but those given in the United States Pharmacopeeia 1890?
appear to be best. These tests have been combined and modified by
the writer so as to give the maximum color in the minimum time.
Modified Test.
Add 5 drops of the oil to 1 ce. of glacial acetic acid in a small test tube and then
1 drop of concentrated nitric acid. Heat the mixture in the water bath to about
60°C., hold there for 1 or 2 minutes and note the color changes. A violet or bluish
color develops in Mentha piperita oil in a few minutes when observed by transmitted
light and a copper colored fluorescence by reflected light. Japanese oils usually show
a straw color and sometimes a very faint blue color, but no copper fluorescence.
Eighteen American, one English and five Japanese peppermint oils
were collected from various sources and subjected to this test. The
American and English samples were obtained from Fritzsche Bros.,
New York City; A. M. Todd, Kalamazoo, Mich., and George Lueders
& Co., San Francisco, Calif. Of the American oils, six were stated to
have been produced in Michigan, three in Indiana, two in New Jersey
and one in Oregon. The producing state was unknown or not given
for the remaining American samples. Three of the Japanese samples
were taken from direct importations at San Francisco and two were
obtained from certain of the above dealers. The date of distillation of
some of the oils was furnished by the dealers or distillers. Seven of the
American oils were distilled from 1918 to 1920, one in 1905 and the two
New Jersey oils were stated by Fritzsche Bros. to have been distilled in
1874. Some of the oils were single distilled and some were twice recti-
fied.
All the American and English samples gave positive color reaction,
while the Japanese oils were negative. In order to ascertain the effects
1U.S. Dept. Agr. Office of the Secretary Circ. 136: (1919) 16.
2U.S. Pharmacopeeia, VII, 1890, 281.
598 ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS [Vol. V, No. 4
of different sorts of storage upon the proposed test, portions of these
different samples were put in colorless, partially filled, glass containers,
some of which were left open and some of which were closed. Portions
of some of the samples were held where direct sunlight could reach them
and others were stored in diffused light. The various specimens were
tested at intervals of several weeks to see whether the color reaction
had been affected. After about two months it was noticed that the
American oils held in open containers in direct sunlight gave a negative
reaction. Also, one or two samples held in diffused light for six months
gave nearly negative reactions. Attempts were made to treat the oils
which had lost the property of giving the positive color test, so as to
restore it. It was found that this could be done by distilling with
steam and at the same time treating with nascent hydrogen, as described
below.
Regeneration Treatment.
Place 5 cc. of oil in a volatile acid distilling apparatus! and add 10 cc. of 2.5N_ sulfuric
acid and 1 gram of zinc (mercury amalgamated) or add 1 drop of platinic chloride
solution. Distil with steam, collecting the distillate in a 4-ounce separatory funnel-
draw off the water; filter the oil and test as before.
In every case the American oils which had lost the ability to give
the reaction recovered that property on being treated. Two Japanese
oils, similarly stored and subsequently distilled as above, still gave a
negative test, showing only a very faint blue tint, which faded rapidly,
with no copper fluorescence.
Experiments were tried to ascertain whether the change from a posi-
tive to a negative reacting oil might be accomplished by other agencies,
such as freezing out part of the menthol, by steam distillation or by
action of different catalytic agents, such as iron oxide, platinic chloride,
platinum black and hydrochloric acid. None of these agents caused
the oils to lose their positive reaction. Treatment with concentrated
nitric acid or with chlorine was found to destroy the positive test. It
was not learned what constituent or constituents of the oil are affected .
by storage with exposure to light and air, but it is thought to be an
oxidation effect.
Organoleptic comparisons were made between some of the American
oils in their original condition and the same oils after storing under
such conditions that they had lost the power of giving a positive test,
as well as the Japanese oils in their original condition. Five drops of
10 per cent alcoholic solution were placed on cubes of sugar, and the
odor and taste were observed. Four observers agreed in general that
the modified American oils and the Japanese oils tasted bitter and
lacked the characteristic odor of the United States Pharmacopceia oil.
1 Assoc. Official Agr. Chemists, Methods, 1920, 177.
= oe, oe
a 7 «
1922] EATON: JAPANESE AND AMERICAN PEPPERMINT OILS
599
The specific gravity and the index of refraction were determined on
some of the original oils, as well as on some of the oils modified by light
and air, with the following results:
Ure PEDPELMING OL. <a. 6 eect o-sie ce wees a ems
Peppermint oil (dementholized).............
THURS SES ee eee eee
Peppermint oil (Japanese fraction)..........
Oil peppermint, Natural—not U. S. P..
Oil peppermint, Michigan pure single distilled
Oil peppermint, U. S. P. redistilled..........
Oil peppermint, pure natural—non-rectified..
Oilipeppermintese eee eciae. acs. secs hee
Oilipenpermimbertecet ings cicc.c cs nesses desc
*After modification 1.4631.
ORIGIN
Japan
Japan
Japan
Japan
United States
United States
United States
United States
United States
United States
INDEX SPECIFIC
GRAVITY
20°C. 25°C. /25°C.
1.4580 0.892
1.4580 0.894
1.4580 0.894
ACAD TON | eee
1.4595 0.8996
le PiGliye Mh | Gmeane
V4G600° |) joes
T4600" | 22S
Mey | Geaeos
VAGIGE |) Socios
A-AG61SE9 |e.
CONCLUSIONS.
It appears possible to distinguish American from Japanese peppermint
oils by the above described procedure, regardless of age, rectification or
manner of storage since distillation. The test, however, will not indi-
cate the admixture of Japanese with American oils.
The index of refraction, as well as the specific gravity, is lower for
Japanese oil than for the American.
The odor and taste of Japanese oil and of improperly stored American
oils were not so pleasant as those of the United States Pharmacopeia
article.
om
vel
he Adil dal
apple
: ice epg
iaatey i) kee
1fe> Jina ee
Laie
105) Oa
ri neon ;
4 napa
Nien! we
a
hee ae
ie “Et yt a
| a
INDEX TO VOLUME V
PROCEEDINGS OF THE THIRTY-SIXTH ANNUAL CONVENTION, 1920,
AND OF THE FIRST DAY OF THE THIRTY-SEVENTH
ANNUAL CONVENTION, 1921.
PAGE
Acetylsalicylic acid
FECOMMIMETUA TOON DY SRAM s siareitc\s(eraicicca se wid Sie & iio aoe aa Ser i aS Eee 581
EO DOUEED Vp alll eeyyvey tye farete oo cuss ai mscictenagars setae oe CC ee ee 586
Address
Pygliand mi resiclenteene srr. acres atic cae cco cee nee Teer ee ee 366
bygley theoembrestdentacracceaeci\sccitts cociisisteee crete eee eee Se as 14
byaMeredith;iSecretaryjof:- Agriculture. . 0.00526. ..0.6---0.00) eee 238
byaWaleyAtlonoranyAP resid en ts\. 07. {sic:.:ssataiaiste safes ores ose 229
Alcohol distillation method for the determination of camphor in pills and tablets,
EON YR ALEC Lope cents See ee ohare ace atelier Oy gee itinete .f at IS EME oe ae 544
Alcohol in drug products
ECEOMMIMENU AT OHIDYMVIULTAY: 5 5 ais:sisratel st atote erates toe Seales Sin. we RN 538
TE DORE DW AINUUECAY 22521 512) ayes ct alo) 5 351 o's) sts) ah yal tions & ade SOIC AON Ee eae Sa cl oe 530
Alkaline permanganate method
to determine availability of nitrogen, paper by Magruder.................. 454
some experiences, paper by Robinson and Winters................-....... 446
Alkaloids
recommendations
[ES7 ESTRCL ooo dina, Poet SHLOMO CIO Eee Cee Amer rat eRe cn 149, 572
yA Omni Lee PEA yarstsher ssc) ato.s sce ieys ese seieusuere *1s) sj suejeeh sensi usyasereieeavaes* scp 337
A OLER Ng ES ISS ee ers (one 215) <yesint sf ses[s Zahn: © agaletens oe aie a fobapeas lakoval oye Syskas a svoune 149, 564
Alkaloids of opium, recommendations by Committee B.....................--- 338
Alsberg
report
BES OAL GNOME AIL ORS alse) icc orsastesc siete hr olesain seakelay aie nei atece wearel ortye wreneteereere 322
of Secretary-Treasurer for year ending Nov. 17, 1920.................. 318
Guplolurtaland Book of Methods’... !occcescccts ca cesses at emesis eye 320
Ammonia, neutralization by boric acid in nitrogen determinations, paper by Spears. 105
Ammonium citrate solution
recommendations
PVA COMMHELCE TA Cyn ercte cae core cite aes SuslsyenS eittoiniehsic tse asisahs eee ee 329
EIVMIRODITISOM ohh sete ore css ceoeisish cle dee ee Oe Me Th wets Sard nae a See 97, 445
MEPOLEDYARODINSOM bce ce cre cece eee eee Tetee inayat 92, 443
Announcement
CHEUANGE IH ASSOCIATE! EGILOTS ees he setn Cialis lake ered te mie alatelte la APalale Helts 2 295
OtMdeatnror Williamllbreand 9 feiseesioes Nels es See eeve ware racts seit, htt 295
relating to
Bac karitirn DELSIOM TEA) OMUTINIS «J0) 08s 510 ¢ ois ip ial peor is iets cseie cie\sheis/siisre + iene No. 4, i
Colisi buted esearchipd persis chawcs Sebieisy-ie ict savers oPeiyaicio = Sains No. 4, i
Application of the theory of probability to the interpretation of milk analyses,
Ad desstbyephey Presidente per ste \asaieieieisssrchascksce ciske, «ihe sbensisuacole iaueicut estos 14
Arner, report, determination of camphor in pills and tablets by the alcohol distil-
ISvein aGidelea! | Lae pp AO chess cn on OCR a OM EIDI Ss att DM Te Ey s Oriya 544
602 INDEX TO VOLUME V
PAGE
Arsenicals
recommendations by Committee Brn. sce ete alesis ellie aye eee 337
report ‘by Emery.).).)...\4. ath dtetda tod fe RR Bac Peach Petefece os! ine, eles sie sorauersiolais 149
Arsphenamine (salvarsan) and neoarsphenamine (neosalvarsan) qualitative and
quantitative analysis
recommendations by Hoover and Glycart...........0.0c0ce sees eecucences 529
report, by; Hooverand (Glycart spire syasueparsieyoyan cua) = =4>u-depsials oielsvniciel« fe eusteiale ie ee 525
Aspirin (acetylsalicylic acid)
recommendation by bal scar cjersuere ieseiene rehearse oe ctpe inte exec ielsole hone tai steve rae 586
LEPOLbl Dye Parl se evs tehevap see oieeyemeonens ve nisvey ot iereiehaie hehe en choaiatalsscustteteet ns ee eee 581
Associate editors Changer. i. <u's lacie ier mys cals chore iiclcaay se el <tpiici) chon eleLeetatacnn te eee 295
Associate referees, officers, committees and referees
for year ending October; 192M si cley-ss eieye ste keeet le stern ole ei> ote evehepdledn cote a ceeet eeee 1
fori yearending October, 922 syste ve eyetels els ern ielee ier eee ee oe ee 352
Auditing committee
appointment,and personnel.) oocyej- sue c iad ole) 0-1 Aenea eee aie et ae ee 79, 428
reporias:hedentiin af askudieay-ke alierbeesietiderads “wid tues seek rickets 322
Availability of nitrogen by the alkaline permanganate method, paper by Magruder.. 454
Back numbers of The Journal, announcement........ 2.60. see ceed n eee em No. 4, i
Bailey,\©).H. report, cereal food Seis) ajereyeross o\elevelois/eisvelorese)\ iano os iakel Steve ieee eam 241
Bailey, E. M.,
report
eryoscopy of mille. =). 22 R= k)., See SEER, Siar. arti tata rcte aoe ape erie es Pace 484
Rien 2 To 5. Soe ae seitivsl ete feito a SKSIAVS) © 2PM) 5 eve Veyeam ewaee cues sin eR icf teRCtoy alte ats eae 288
Bailey, oH.) report, balting powdery \a)s)-c)-t-1ere o-t-let isle eetelnvola falc) ointetelehetete etatete ven ae 514
Baking powder
carbon dioxide determination, paper by Robinson................-..020005 182
determination of fluorides
recommendations Dy, MOrtomiejysye <= s)s\eieloie oiote/aie ea) c)p ole tere) 0a ila tienen ean 524
Teport by, Morton’. 2) dsislie eee silo sle serene cos epeliatele ts nyt ee 522
recommendations
by, Batley/a3/3.- sek 66 ae «odie cea ae ia riteecel sae eee eee $21
Dy Maines oo). \o'5 5 cts tains icveie a: 050ies)opeoyt gabe ie al jaoh hale \. dn aie ete 182
report
By! Baileys ic.cisroxovarsys seuss leveucie si oierelsse ote sete otelokels y=! o)aps ielatabale (alae 514
by: Mains). 0/2/52 Sice cis ote wieis| siateresalecelwinls ysis te ns tatore eyo eye etek tee ee a 179
Baking powders
recommendations by Committee! G. oi ii). ee coe «nis + ne /> apaleyatehete tes aiee tel rela 348
Baking powders and baking chemicals, changes in methods... ........+...++e005 311
Balcom and Yanovsky, paper, note on the polarization of vinegars............+. 245
Balsam and gum resins, recommendations by Committee B..............--055- 339
Bartlett, paper, distillation method for the estimation of borax in mixed fertilizers.. 88
Basic slag, vegetation tests on availability of phosphoric acid, report of committee
(Haskins) !cisiis.c vs sais ad aaldig dca diapelecever eva vere ORIENT aMe PR REEE I (prerete 317
Bates, report, committee on quartz plates standardization and normal weight. ... . 315
Baughman, report, methods for the examination of cacao butter..............-- 263
Beers (limits of accuracy in the determination of small amounts of alcohol), recom-
mendations by, Committee'©: woes eG sess nit selerelsiem creterm etintetsteteta Me.etetateraaee 342
Berry and Paul, paper, Kjeldahl nitrogen method and its modifications.......... 108
Bidwell; report; crude fibers)... os => < haeienieieiee + om «ale nloewlelotoiapelalelainialelw iat 55, 421
INDEX TO VOLUME V 603
PAGE
Bidwell and Bopst, paper, study
ofthe details’ ofthe crude! fiber method)... 3. )isiee.aeh oa Po. WAS. ees Mae 58
of the Gephart method for the determination of crude fiber................. 422
Bigelow srepore,, canned foods. st, f2 JA Se ese 1G ee en Pein 225
Bisbee
paper, detection of adulteration of shorts.......5.2:2..09.. 0.020.002 eee. 74
KEPOLE Pectin iruits and fruit products. .............:2.se0cacsss sent eee 224
IVCRE. imeyporit, Sule oSta lS 56 ee oe at eR eRe Bite erat 149, 564
OAc GRO ME CIEOLS ALE POLE PAUSDET Eo coy 0/cs0yey5\ osayeiesspa,<iererayasaes « iis cleisinsjehew opie esisieee : 322
Bopst and Bidwell, paper, study
aigdetallstolteridens#beramethods 44440... 2 once Laie eee 58
of the Gephart method for the determination of crude fiber................. 422
Borax
determination in fertilizers and fertilizer materials
TECOMMUCOGATIOUSID VOIR OSS! c-yeactepen) stele ies 4 saci ees ead See bearers 85, 442
RUEORE IY LOSS 5 an ads CB BOAC EES Ste oe Set a a ee a eee area 80, 440
in mixed fertilizers
estimation by distillation method, paper by Bartlett................... 88
RRR (o7 IDSAr rere ae CORPSE oC EAA ance Meee Meee eee ee 86
Boric acid
for neutralizing ammonia in nitrogen determinations, paper by Spears....... 105
in fertilizers and fertilizer materials, determination
PECOMUNEUG A HONS ID IN OSS o)4)4(syet0s/e/s)ensyeus sens beacspsteustene ari alsa cists ct stable 442
TE OLEM MESS Om pat Neral > (o,f or eves< hain ois ysiesceusi-ysgcuto Tek -usich saiesed otannsicmcieysieiee 440
Bottlers products (soft drinks), recommendations by Committee C.............. 342
Brackett,
CADIEMATY {OHM VV SEMATTIUE LEAL: 5) oi0.av0\n! sie ous 9.9 atsiois's 24s: spefetpar tay stele -fe¥ebhsehsyote tse No. 4, ili
RE DOR OMMNEEEIZELG NAN ayaa ciate’ creiels| «aie oe) es) cl avers, ome! easel Blobals « ot eldrapetels aa merci 80, 439
Bran, ground, detection in shorts, paper by Reed......-........2-0+0ee0+ee0e: 70
BLE WStCL Le POLty SHPAL-HOUSE PLOCUCtS... = o\. -)- =e cin 2's osebelelsiete thot sole eloye wera etvtarstel« 437
Butter
cacao. See Cacao butter.
fat, determination of ‘“‘turbidity point’’, paper by Seidenberg..............- 512
Cacao butter
methods for examination
recommendations by Baughman. =. ..... < .1::.< stairs wielslelenels ee olen 267
Cisse LSE Alls thin ipa pice a boro moO pound 3.bunochohogc odie dance 263
Recommendations Dy Committee Gs 2.4 of sa sin ci= + Seite ore - re ee ere etoile ai 347
Cacao products :
determination of shell
recommendations
ey Caress (Cus ang sa sen cbod ce eee deo cabEacsaD osemEEoAIDeOoe 347
(oy? TPalos. ob - Soead nes ORs aes SAO OB Sb Don Aba daaSesaa OO en OU SEN = 259
apo? ly Teer as ooo oode Gan eenoe SD EUOa SED aa SOD OceieouC oma OUDEr 253
recommendations by Committee C.......:...:......---2--2--- 2 eee eee ee 347
special reference to shell content, paper by Silberberg............--.---.--- 260
Calcium and magnesium in the ash of seed, recommendations by Committee A... 330
Caldwell and Moore, paper, some results of the determination of potash by the
Lindo-Gladding method using alcohol of various strengths in the presence of
Ted HIT SI ODE. Sok Sel AS? She SUR Ae eB oad Sense ee obe memobeerenpemeboee 136
604 INDEX TO VOLUME V
PAGE
Camphor
in pills and tablets, determination by the alcohol distillation method, report
by: Arners 5) Gatto Si eee ene ee See ma ace ec eres See 544
monobromated, methods of determination in tablets
recommendationiby Wright seceee 2. .- sek selene ce eaeee back cee ee eee 589
report:by Wright) 5 Tenchi setae capo a Se ee ee eee 587
Canned foods
recommendationgibya@ommittee|Gu- posse skeeee ss ack ee nee Seen 341
report byabivelow#: 20)... tising 6 kate bie dine ns Contete poe een Ee ee eee 225
Carbon dioxide in baking powder, paper by Robinson .....................-. 182
Cereal foods
recommendations
DY Baleyyin schon sinister 22's cieea e cale cle te inionie tee tT at Oe RRO eee 244
byCommitteciG. eo... ko Sais Grelareevage sie eR IOR See aeien Cee oe eae 341
report, 'by Baileys soeaticuu saeco 6 ee tueiot ne cere ee a ent Tee ere eee 241
Cheese, moisture determination
recommendations by Mitchell. jens sone essere ca eee ee tee eee Een 506
report by Mitchell oa. ea. oeace ceed tice e 6 meals ce toe eT ee 498
Chemical reagents, testing
recommendations
by Committee Be oe iain. vitecs elecdiete 4 cielo o/s ic oyate al Salo: shay stare iar Oe eee 335
by Collins re re eee ee ee ee 54
report by Collins i.ccsdoeence se re he coe te eee me ee ee eee 54
Chloral hydrate in drug products
recommiendation'(by Murray. .5..- 4 0c): his ae clecielels eles cle we etche Stee eee inane 542
report by Miurray2c cia ann ee te eee ee a ae ee ee eee $41
Chloroform in drug products
recommendation) by (Murray, « 0.0505 0+ se crernis@ cin wsielal ea ote iets eos See ee PIM S41
report, by. Murray? :o2c20 cd 205 faccc cao de on caicke ve cvcta se eee ne ate a en 539
Cinchona alkaloids, methods for separation and estimation
recommendation: by: Eaton’... i... - « « = «colstelclaiel a) Slee sels see 596
KEPOrt. Dy, EeaAGON ss, 's)<<s:'esrs 2s. a7esa sas oss uatetorseiaveve.sislele ei grerein ewes oversee oleae ae ea 594
Citrate solution, ammonium, recommendations by Committee A............-... 329
Clark and Keeler, paper, modified method for determination of phosphoric acid.... 103
Clarke, report
metalsiin £008 25s). <..sscicielsie scieicje a eisisis © eels se Risieiele\e/ele ace Stelle ei ee ae 219
CUPPEMEMNE 5s: 55 cia 5 ays Gye ete lesecosr0s 5/01 eon We 8,018 0)0 1 er opa oie SpOPSES Cah ave RSe ane Heche nae 547
Codeine, methods of analysis
necommendations by. Glycart; <<.» isla. lise) <-.+.->1<\+/Ieimeueieig eielh seh eee 155, 575
report by, Glycarts ooo cyan bce casi stole ORBEA musi’ cata ea ceo eae 150, 573
Coffee
recommendations
Dy? Gomimitteel Gos es ves saree o)c.2 cyece meres osc syajeuels svrsceesraecia teal ae ene 347
PYLE per ses ee See cutee ste ons bie vals Gls. 5 alnge Sn LepeR Teeter 273
report byvLepper.\ie ss eerie’ eels s wicca he malate ie hers +s clean (een cai cTe eee 267
Robusta, paper by: Viehoever'and Lepper.....:....-%.- +. cs eh seems 274
Coffees changes iinimethods:siiises oo ch ee ee caeelceeisier: cove ant eenere tener nee 311
Colling; report, testing chemical reapente:y fests cle pie cle hiatal eter 54
Coloring matter in foods
(Sree Re Oc aet o omIC Oe Gets 0 Fen en coe Toss ato Gasca anus Ososan8 298
recommendations) by; Gomumuttee (Gs). cjeceisinic als «i> ete Tere eee eteiste iste eee 339
FEPOLL, DY, Mathe WeOMrars.s 5:4) +\0,ece,+)0)4yo7aiSuehase el fosters calsxenel vial afekeheis beers tees ene eae 196
Committee A on recommendations of referees, report (Ross)..............-..... 327
INDEX TO VOLUME V 605
PAGE
Committee B on recommendations of referees, report (Lythgoe)..............-..- 333
Committee C on recommendations of referees, report (Doolittle)................ 339
Committee on auditing
ERO MATOTE autal pe OSes Bers MES HORSE Aan ares nes = men 79, 428
FRB TREs oc oc ac a porotnd ao CU CU DU ECUDO OD RBRSS EO Cheri Men oS en ie aeeennoe 322
Committee on editing methods of analysis
RecA TS ERO EDEL Ee RAMEE es Sate cya ecu w= pice) hoo a:0p5 ala sociei sta ja Sedsees asesb Lie ars, Bos 314
EE HOLE MOONEE) oleic itor (ore kee ss oh spn) s Gr oseseine hiaisye-ardioré,d.e.swioimeivinemee 4 nenic 297
Committee on methods of sampling fertilizers to cooperate with a similar com-
mittee of the American Chemical Society, report (Jones)..................... 315
Committee on nominations, appointment and personnel..................... 79, 428
Committee on quartz plates standardization and normal weight, report (Bates).. 315
Committee on recommendations of referees, report (Ross)...................-.. 326
Committee on resolutions
ZEPUM MICH Anal PAROINE Loss AAO Re eCe ee Nese pec E Senn Se eran He 79, 428
ROY (CS) 5 Su Nd poo coe SOC NODE TE ere te ae meen tar aan anes 349
Committee on revision of methods of soil analysis, report (Lipman)............. 316
Committee on vegetation tests on the availability of phosphoric acid in basic slag,
EE POLES (ELASKINS) Reef reyete chaos aya eiei siete 6 cere avels-atialeiee s sisiainsisee case cee ekee 317
Committee to cooperate with other committees on food definitions, report (Frear) 349
Committee to wait upon the Honorary President, appointment and personnel. .. 79, 428
Committee to wait upon the Secretary of Agriculture, appointment and personnel. 79, 428
Committees, officers, referees and associate referees
FOTRVCAIAENGIN EA OCLODEL pl Gakic seven: hie ere vie c clate ns crete etter ee ee ai aye 1
FOTsVealseneinipaOCLODeH GOD 2 enor. vais vision ce ee disclose ee oe Hiei Sole tee silars 352
Composition and preparation of a neutral solution of ammonium citrate
TEEDIRMIEUGALIONYD YP RODIISOD sfipst cise sec ss, sse cles a sroe ee ce me oe tek eee sie 97
ETOH: Ey ING SNe eh ee eee nA aes Are! area 92
Composition of commercial phosphoric acid, paper by Ross, Durgin and Jones,
RCL CLE HCC a en tec reve pens isle) siarere ici ciaisintt Heid elem miguiers fei omeatane 464
Contributed research papers, announcement.............0--eeeeeeeee eee eee No. 4, i
Spokapapens bickering BOLdeaUX SPYayS..scc sce cece ec cee ees ece eee ale mec ae 50
Crude drug substitutes, identification
LECOMIIE ROA TIOUS DYE VLE DOC VEDI o/o,ojareisisyinis 2;* e512) elenevs epeleseisiarescheisiel el ss sunreleretonets 563
KE POLEMIC LOC VEL po raeteasteterayercre\ seage) cies SS aise) eos ave sve e's ettle,clore atone etapa tote eic\s 560
Crude drugs and spices, volume weight determinations
TEC OMMUEHOATIONS ID VAVICHOCVER.. fc ccc oe G.cir cis cies o's le oreisiaiejasisoreine ce ealsietner ces 557
LE DORE VE VAC HOC VEL a trtrar ta): 2 cite ota lcys/<ye b s/s 0 ais viens’ s custo lotions ae eee noratate sree ai 553
Crude fiber
determination by the Gephart method, paper by Bopst and Bidwell........ 422
method, study of details, paper by Bidwell and Bopst...>................- 58
recommendations
levy iidivelle Sc o's abla dete O GO OneT GOS CRD SOROS uiciensnn aasae 57, 422
ayy Coriainiiee 1B... cope Stee oR ecrd PETE CDEOe obo Deer amedacan Beapeats 333
TEDOLSUBESIG WEL Unsere tae tre otarctaatersiete es cles © avelcleltsiejors e/ete outs aaa aisiele. oe 55, 421
Cryoscopic examination of milk
RECOMINENUAROUSIDY) HIOLEVELS nis cisisfo cle cio cies © ci teinin c/Saleies sielsiereisicis seiteiclers 484
inafecirt ley? RIQRA TiS o do Sat boe ne SOS DOE eRe ane aaa DOC GoD Unoobenoon ond 470
Cryoscopy of milk
jaar ior ITA eeeduoaneoconsBek JOOe- 0 DPB OUOUU DET OOeODOOMInBe Gs 04.5 cc 172
recommendation by Hortvet: 2. 05. i902 ses o's ses wae alain enclave slvine = a
TEPOLEIDYAOANE YA toes oes cele sree hse datere enchants wa lee Whelolmte tals ino) - eer takaeaieral =
606 INDEX TO VOLUME V
PAGE
Dairy products
changes in’ methodswra esi) LE Se ate nae teeter eters aatetcte a eete a ceae 310
recommendations:by!Gommiuttee "Bia, 22st oso ee eee een eee 335
Deemer report, borax:inimixed fertilizers)\)5)5 cs eic~ cio viciers osisieere teins eee ate 86
Diacetylmorphine (heroine) methods of analysis
recommendation bysGlycarticir-s cries ek ailcs tcc piece oie eidlteenein erie 155, 575
reportiby) Gly cartes nic sis wias wierewiviceee bee sebele set eine te Cie e eee 150, 573
Dicalcium phosphate, limitations of present official methods for determination of
insoluble phosphoric acid, paper by Nelligan.................00.eeeceeceeees 97
Differentiation of Japanese and American peppermint oils, report by Eaton...... 597
Distillation method for the estimation
of borax.in mixed fertilizers, paper by Bartlett..................s.0.+«see 8&8
of /santaloljin’santal\oil, paper, by, ElarriSOn eo.) ro)-% = o\ng 410 cies) vic ieieicloyeiele steers 166
Doolittle, report
of Committee C on recommendations of referees. .............200s eee eeeee 339
of Committee on editing methods of analysis... ..............0.2eeeeeeees 297
Dried milk, moisture determination, paper by Holm...................+.00---- 509
Drinks, soft. See Soft drinks.
Drug products
alcohol determination
recommendations) Dy MUUITAY su jeutele sole sielacsic/ otis sicicie le iaisiae kleine helene 538
FEPOR COV MMA gis ye valbaeda shelled suru Bros uc-nehepaievels: asePMcalakeiche telleastel ter eae 530
chloral hydrate determination
recommendation by, Murray. nek + cic sos + datas clair ei iets ieee 542
TEpont Dy, MUTA... 5.0: oe tiavc terse Sines i o\sa, cre Seiya ALO eine eee 541
chloroform determination
recommendation Dy, MMA. o.i< «) «\e o vieleie) aay ieieib siete tel ates ole teledeeneiere ee 541
report: DY AMLULLAY wie.ccare. chats clas aeyche’ sxeionel ehe/eie ere of sete) oyna ala eae ee 539
Drugs
and spices, crude, volume weight determination
recommendation Dy ViehoCVern. © co euereseas, -. 522101" seyueiel cesses veieiaie) ee 557
report by Viehoever sic e dics sie:s fe «10 noseneerap aa ale suea ibe betes ye ete ana 553
Changesm methods nile nies sols vrai aieinie mieials aca einieds (naires ack kee eae 314
laxative and bitter tonic
recommendations by Muller... i. cesses cists sais <5) = e sueene ge ale eee 581
report. by Fuller’... :.<\: .jssGantselneynig paige 91s Osis Ge ene eee 575
recommendations
bys Committees B caves ctriciccerc cies) leysiclois.c)si sta ttreltre's crcl e) ie Reieeeeait ten ets ei nana 336
BY HOOVER wes choise se Gy ois sa fen 2) ste bie neie se meatal ela, Siete Pen atone ee en 148
report
by Hoovers.i.c: ccs asabheia-ieeletetse: ok poets is lals s tetetet stati enna 141, 525
synthetic
recommendations
by Committee Biv isc:s.ssy. «ss sislsiors cylaroos ss ictelelb ahelsjahera isles sep nanan 337
By, Wrights) 5 o:icacrcs2 5 iclocayan «ane n nve'wiaials lure ielete hiel/ei evens erie! Cen ances 150
LEDOKE DY WTIRDE o. 5) «arc, /alo)<iornpe) oils ss e/aychsisbetsletstalelb es is ave tte ais fata tata teen 150
Durgin, Ross and Jones, paper, composition of commercial phosphoric acid, ref-
QLOMCE os... occ: kusteseuausyr’aretce inse cain covace piers ioe nxetie e/stetalatsvaye elm ty ia tes Tenet ae 464
Eaton, report
differentiation of Japanese and American peppermint oils. ............0000 597
methods for separation and estimation of principal cinchona alkaloids. ...... 594
INDEX TO VOLUME V 607
PAGE
Editing methods of analysis
reappoiutmentyol Committees ce more. cine coe tien eee ne ee 314
Reportior Committee (DOolttle) ian. cee e coc Scan cls Sas cies ee Cte aero ae 297
Eggs and egg products
recommendations
by: Committee Gyriosnccienie ie ob ao slate nein ree sete a een eroeetes 346
(Al bist) 5 asain Ain Bo GR Or MORRO EEE orc AEn On acorn SH oact 194
KE POLE DY PE OULIOM.. Cer) state aie crcl theroleie ei areias Cie ee ee Peele ie Ons oe 191
Mery, (report ALSeHICAISY<-o-te</siee «preva crsieiel ates icra te Hotiperadee seasnocsanoosce 149
Errata in official and tentative methods of analysis................2000-e eee eee 298
Extracts, flavoring .
Rebar] POS HMUGINIE COGS 1 cere cove si syayavctoeietanste ge Weal everaiaia ona eae anole cciomal ae eieteteesterete 308
recoimmendatiomiby, Committee Gr. «ts, cwisl «cis tee isis aye sverel ore eveiesere ete nieces 342
Fat
butter, determination of “turbidity point”, paper by Seidenberg............ $12
determination in malted milk
changesin-omicialy method ec -<)::. cise saree nie seyaete sees rete lalstsie sersyareemrerere 509
FECOMMMEeNAAtiONI DY, -NCISCEN, sem ietye sisters o rotereiioys nies cefos er nieeae aes 508
SEPOLEIDVAINCISLET «ciets.sisie.s siccieis ciaiefece cece seem cleie ae eis ets teense 176, 507
Fats and oils
GIBATES A RCW NO Bi aneesoo nS eCoo eee CUT OaaaoOn oondaene ss coedascnudas 310
EFHIE) oc oc contd soo SO0O RDU RE CUDD Ooo One On GetoneuMouoScEtacsoUoEaoonoe 298
recommendations
PVA OUITMIELECEN Orne yee ers clets aie ss rays arate ni seavetale ayer eunte tuapate a este eet eisia) ove 346
ASV UATE SO MMe eet ae ME Tere roe ce, éisscneis a iatahave le dG bration a neeratelesstetsieo atele 512
IDM? INGE SQ GSS phn OOS Hoe COTTER AIOE SETS STE DERE IGG nea Pieter of a9 179
report
BS VMyAANIESOM ree ay erates ee levereis eae ici. susieteiiaee’ o eisieieieieieiars. stauevaave ecarapetesoreee 512
[B57 IMGT re Soon bids TORO SOS a REIS Sora gma enero met orcs 178
Feeding stuffs and foods. See Foods and feeding stuffs.
Fertilizers
Ghia PESRAT HIE LNOUS Roe e roi scisve eicroe cei c race cee ie Seles a tets Oeics tlc te 300
committee on methods of sampling to cooperate with similar committee of
the American Chemical Society, report (Jones).........-....2.-2-ee0005 315
determination of boric acid
LECCE NMA LIOUSIDY {ROSS err celeste era eins cisveres aie cetera eietermelern amare 442
REMTTE AIRC. Sigs sega phidouiow De SN BeOebdatnaAsee onsen boneopicombos 440
mixed
boraxicontent.ireport by Deemer... ccs... ce gee ce ees eseaie sells eee 86
estimation of borax by distillation method, paper By Bartlett.G28 asec 88
recommendations by Committee A, report (Ross)..........-.-----+---0055 327
EPG RO LACKEL Eset errs ce Peters c cicraieis's eres Nero aia \erainie crsiee nieietei ceteris 80, 439
Fertilizers and fertilizer materials, determination of boric acid
ECCOMMHEUCATIONS DVM OSSs se iaas teleisien) a tele ei ciee ec lare ereie ele ctersisr eh wioteleveneter slots 85, 442
MUO: lay” IVES. + OLS eae id top DO Sa DEE AEC DGGOOUCOU ne I5 docs 80, 440
Fiber. See Crude fiber.
Flavoring extracts. See Extracts, flavoring.
Fluorides in baking powder
KecoMiImendations Dy: WIOrLOM ae --\s foe se ss 22s ele seleielasialelefe eeistelelsieleiniciale 524
RETOLD VAIVEDEL OME critters seer cin cca rts ieee cre ait mtetereieetatet: 522
Food definitions, report of committee to cooperate with other committees (Frear). 349
Food preservatives (saccharin). See Preservatives.
608 INDEX TO VOLUME V
PAGE
Foods and feeding stuffs
changes,in methods -s27cnspi. sizte toisas ake jes ster apeyoceuevalehaaie meals alta eke eto Bee 304
recommendations
by, Committee! By in... .2néaatyschcemOaistans ane ne Sues Co eae Rees 333
bys Re eed ios ia scape a tersje ces atpiar o> peilers wie olais assis 6 nye, sig} < esses foliha yee ee oleae 420
TEPOLE DY JRECM Gi cctsts is. cis un'ay scope cne store eo ete ees Ee ee 418
Foods, canned. See Canned foods.
Foods, cereal. See Cereal foods.
Foods, coloring matters. See Coloring matters in foods.
Foods, metals. See Metals in foods.
BOY; TEPOrt, POtAS I. 6.5.5) esnycyeraso: os 66.6 eis geis eso aeons eis evacsis stevemetectini aie lee aie Guero 456
Frear, William
announcement of Geathy. <i). cine lath lacs Jove 02M fag oa ape aceite ne ace 295
obituary, bys RGN Brackettryic ce acs.) aie cae eet aire eet ee ee ee Nord, iii. VI) -
report of committee to cooperate with other committees on food definitions.. 349
Fruit juices, detection of methyl anthranilate, paper by Power, reference........ 225
Fruits, pectin
recommendations (by BISDEE. cs shi o.. eye wl Sere, oe: Pee ana ee ke Git eee ae 225
TEPOME DY DISDEC i cise ficcie oth sce ere sce rece eal cle oe eR oe esate oe 224
Fruits and fruit products, recommendations by Committee C................... 341
Fuller, report, laxative:and’ bitter tonic drugs... . 2. ee... o-.es cs ome seen 575
Fungicides and insecticides
changestintmethodssw.cc fe cis cieis.cfacisinlenie wets aualees ace eecie eas ee ee ee ee 304
recommendations
by Committee Ar cheb. ckeholege, sia okie ae fo tare nis fale te haa ee 330
yi Grahiamievetes ce cle ates! oie.accistelers Cooter ewetslelepe ovate Statens oie) a ae 49, 403
report by Grahams. cc.cn see sc oe sls 0s) Lisie oe, oe saveleinirn elevates odae rele anal es eee 33, 392
Gelatin
methods Neve 2c cei <5 walela oe Masel oie. o/c) Mois Chetats fe wimtalenees eke eee ae 343
recommendations by Committee Gere. a. p0 ssc ie a ee © utes oi eee 343
Gensler, report; stockfeed adulteration........5...0..0050-++ee+ses sees eee 424
Gephart method for the determination of crude fiber, paper by Bopst and Bidwell.. 422
Glycart, report, methods of analysis of morphine, codeine and diacetylmorphine
(heroine) oe eso cakes cols enc 6 Shean ie B'S ince pcas' chalsielscnibie Reacilin okie eet 150, 573
Glycart and Hoover, report, qualitative and quantitative analysis of arsphenamine
(salvarsan) and neoarsphenamine (neosalvarsan)...........00 ee eeseee ees eens 525
Graham, report, insecticides|and’ fungicides: .. «).< 00. + wise + cine nisl aeeianiels 33, 392
Greensand compost, availability of potassium in pot culture tests, paper by Smith.. 133
Gum resins and balsam, recommendations of Committee B...................-. 339
Brand, ‘President's ‘address... '....../..<faas teh aumaenr ane shel soa in acne et laa e ae 366
Hanson, report, method for examination of procaine (novocaine)............. 163, 589
Harrison
paper, study of the distillation method for the estimation of santalol in
BE TACAICOM Ne tote so te Geis) ores roel, vie are ote iatitaicss ei n\shers te vie celeze% felts vs) o/c cnt eee 166
report, estimation of santalol in santal oil by the assay method of the U. S.
Pharmacopeeia and by the distillation method.................+2s0eeees 545
Haskins, report
available phosphoric acid in precipitated phosphates...............0++++05: 97
of committee on vegetation tests on the availability of phosphoric acid in
basie slag, ie. tiie ceca abate cle a epeccioucsaspsb s cpheale Laces ices ee tanat tial 317
precipitated: phosphates: ......<.: ciseiveperans echt antl « -oieiecdee sib SA eee 460
INDEX TO VOLUME V 609
PAGE
Hazen, paper, determination of small amounts of potash by the Lindo-Gladding
MECH OG arcatatersvanstep ates octet Marl states tenataleleatatslAan orale stole slelatetals eee he oe ele be me 456
Heroine (diacetylmorphine) methods of analysis
EECOMMENGALIONS IDA GI CAC rears) sped osee) os eresederoistescyerere\etoue ty einacsrelevaiciee eiets 155, 575
Teportiby Gly cantss: Te oe ee ee eee ee Soe SEE TOME 150, 573
Holm; paper, wmoisturecontentiof driedimilk: ...2......: ieee cee se eee: 509
Fronorarya bresidentissaddresa tt or paratetoio'lahefe7. alate lnvetelotaee ernie autor teen trees 229
EAOOVED: KEPONE nN eSj2cs 4,55 55,4 seis 2:0 sess oiesaiei > orois los Breelese wievsiets Abate oer elev eee s 141, 525
Hoover and Glycart, report, qualitative and quantitative analysis of arsphenamine
(salvarsan) and neoarsphenamine (neosalvarsan)...............-.020-00-0000- 525
Hortvet :
PAPEL ACY OSCOD YAO kame eee eiyo nce ciciniectre eacleteiaevar eco er eersrerielsteieieteeioe ee 172
Feport; cryoscopic:examination of -milket. See oe ce dete esse ects ser 470
Howard, paper, effect of the use of different instruments in making a microscopic
examination for moldiinitomato products. 2.2 -- octet ee eee ees oe 226
Identification of crude drug substitutes
FECcOMMendatvoMmpby VICHOEVED ac ost ese eee ee oe cere eee eres ie aie ehe nee croton 563
LEPOKtADYAVACHOEVELS apsieieye sis bbls 3. nie. ove eee oe aisle a stetele oe tietleee sees a eee 560
Mriclexmennct tavever forcierst $i aie te vay cote) oie overs (ster chess hove) susiias Spot nrararecaiay weaneieveceetaeysheucvs cepa Aare 299
Inorganic plant constituents
ehangesimemethods sas Soe coe sere ene eee ere cine tn aeetafate eletereislernleit Maree 300
recommendations
by, Committee yAse ey chir sarsateccteie.cis.6. 6 <isin oversnezsieieielsie's siviaisisiciemeesteshe e war 329
yg Viigelie lhe spivuepstre cyan tos tei ays esse cscs) ies 2 .cle, Sole t ass eS bayer eaole eaters 136
love LehA eae oomataia 8 404 od 0o SOT COToE RO nOOr An On te Crmc Teor ecinriids 468
report
PY A Wirtehel lee ey ves re apetpeye ccchetare ees ce eee eto says ave etal otatt ate lelast anclte eid eye tone 136
lai lee hg esy ie aloted o ecko Cote Sic gIOIG RIGGED OI RE CIC Oe Eee RCE I mie 467
Insecticides and fungicides
Glan mos Tals nets Sn q plod doe co COCO OEE Radu TOS ESARSOSLnabon bcinpad occa: 304
recommendations
yAtBomimitteerAn steele, se cis asm /sit akeve cestclers inte = ickes, steraie arabe tea telern trees esi 330
Poy Gralla mt aeeryarseie ev cyarc ciel eetetelicievclciciellchstelokelay siciatelct store ateyeh fatevayalisra sien 49, 403
ME POLED Va Gralla mi mie yela cere ialasess/sia)siere: eiclareis aisle eisicinetsjevel ere/eterel state leveiel efelaiste 33, 392
Insoluble phosphoric acid in dicalcium phosphate, limitations of the present
official. methods of analysis, paper by Nelligan...........2..--. ee ee cece eee 97
Investigation of analytical methods for the analysis of silver proteinate
Recommendations Dy sVItChelli.: 4c acilete ee tie atitre cise cites stint Tekeretreitactarnels 543
ngpaaely Whig tlle condndesonavbaboedpe buon ustcomonobrcrobocs Don dcboooc 542
amlesomneport tats ands Ousmaicsmcersace s sieisis sie is. eis svelsaci ci etal ete etalelonereretatsrerere 512
Jones, report
MAS PROCNBotooege ce Cobe ERD Ee ROUOCDOODU IU UCU CuadaceavenSenbrsanocio% 436
of committee on methods of sampling fertilizers to cooperate with a similar
committee of the American Chemical Society.................222000005- 315
Jones, Ross and Durgin, paper, composition of commercial phosphoric acid, refer-
GACT gdia'did od sed cgiNod eo OU UOOD Ol CO CODOO Hitut om Uicdd OMM ODE ondoDRobodcond 464
Journal and Book of Methods, report by Alsberg...............-2eeeeeeeeeeeee 320
Keeler and Clark, paper, modified method for determination of phosphoric acid.. 103
Keener report, maltose) products... - ic. lane see ne + eerie se eleiteiyels cesta a 436
610 INDEX TO VOLUME V
PAGE
Keister, report, determination of fat in malted milk........................ 176, 507
Kerrsreportfats‘andioils: Anica nine cies mnie aboie oc mre neo Soe eee 178
Kjeldahl nitrogen method and its modifications, paper by Paul and Berry........ 108
Latshaw, report, sulfur and phosphorus in the seeds of plants............... 136, 468
Laxative and bitter tonic drugs
recommendations by, Ph ullenv i we eiwie > am f+ dip ckanc -aeeel ie ao Oe ee 581
report by. Pullers ce ese ace aisles sccrotetae tere, biareeo. so diocese enero Be Se ee 575
Leather and tanning materials
recommendations|by /Veltchian.. tacerrdeuicen) tacteaciadeei rian a eae 391
TEport Dy VEIECH nec) silaid asin desta went a eid eipnls roe ety See ae eee 32, 388
Lepper
paper, salad(dressings and their analysis.35 4. 44-)e0 seers ne ase ee 248
FEPOLt; COfee,. ang Peer Rtas m arts sate hdr ike tngrhad » a shale nineties Sake etene 267
Lepper and Viehoever, paper, Robusta coffee. <i. < «asses seine < oss calvewes 274
Limitations of the present official methods of analysis for insoluble phosphoric acid
in dicalcium phosphate, paper by Nelligan.............00-.e0ceeceeceeusees 97
Lipman, report of committee on the revision of methods of soil analysis.......... 316
Lourie sreportion\egesiand egg products. .......,102 cosse ek cee ee eLE ee ee 191
Lythgoe,
presidentistaddresssz. sSiyera). hitraes Genie asa’ ecis eaaaronr ey eee 14
report of Committee B on recommendations of referees.................-.. 333
MaclIntire, report
SOUR Prepare evste Anes Se cse eh ciele eves loiane law iatabhoicas os sels bce oe ea tee §2, 405
SULA 5-sst fe iso: ye fous: 3) actu: rae ysis, sae ple byeis is a Suevendeuteteco aise terete ee ee 418
Magnesium and calcium in the ash of seed, recommendations by Committee A.... 330
Magruder, paper, availability of nitrogen by the alkaline permanganate method.. 454
Mains; report; baking powder... ./27) jose eee a se osa 0 sees aon eae Ee ee eee 179
Malted milk
change lini officiall method piu: Sete s,s. 102.0210 coe Ssis geal tienes ae 509
fat determination
recommendationsi by. Keister: ./-;i ens devin les code ae 508
reportiby: Keister kre cue Aa. cry iioow opeere mtel, nn eee aaa 176, 507
Maltose products; report by, Kieenen..). 0 ...)., « «0+ 1s s/sig')s oa.) aa are 436
Maple products
recommendation 'by Joneses, .siirqdaritiet ual. urareay \abratn iis dolla eee 436
report by Jones gins, cmegten Ss fee Pacts 1aiait was) ea A oar, ate eile ee 436
Mathewson, report, coloring matters in foods.............0...ecececuveeeeuues 196
MeCall) report, potash availability.sj9..c\cbie cts le siete tac ate cis eee ee ee 132
Meat and meat products
changesiin methods.) 5, /., .:,<\satstsye:s sre /ascekaieie’ euevelahe sae ites ae ns éwinis 309
recommendations by ‘Committee 'C a5 vaccines <aicccieiceitie ere. icc oe Caen 342
Medicinal plants
recommendations
by /Gommittee Bee. i..s:5: eather biitew ech miaaine ont Rm eerie 338
by sVighoe etait co pivvearsgeioreiehs Bee dyend a hanaepaaters Vain Wiles te eee ieee On ies 163
report: by WiehOeVver sr. Sew alsmic eistataiel aleiaten ieleta:s afaleisinis ee. cereale ee ROE OE 155
Members and visitors
at‘1920 meetings viv cn gic nar. pire enteral & aeolian Selec l eee a neerenes 8
at, 1021) meeting: i: cicpndsuerptoioietefaaths eels hapten dieeld ua nr flag vce eet 359
Meredith, Secretary. of Agricillture, address. <0 5). 1. «. cersjesdicussss eins ei rn 238
INDEX TO VOLUME V 611
PAGE
Metals in foods
Ghanpesammpmetnods Sere jars sco, oss afer oS a ore sysyat ole sie clare, arokans © auoys oheia eye weavers 307
recommendations
ya Glarke pean eeisin o ao atecaa ews aoe d janie tags tiene iercicae cree Oe 224
bys COMIMIELCE Cres esr oe ie Berea One he Se rele eran aera oe 340
FE PONY GlaL kerr setae ete cere ta ats ol aietsce Die tale jee sicle Ole utatteelayers ceteioes 219
Methods of analysis
Leap PoOmMement. Of EGItIN COMMICLEE s.< (0 > «a5 oie ieiaeyslein cis crvercicliniciieie cleats = 314
report of committee on editing (Doolittle)..................-....--..++--: 297
Methods, official, change for determination of fat in malted milk.............. 509
Methyl anthranilate in fruit juices, paper by Power, reference.................. 225
Microsublimation of plant products
TECOMIMENGATION DY, VIC HOCV ON oyster steno oisscis/aie oo) stay o.3,cl- Slaves ciel teverevererreterate 559
FEPOLE DY pVICHOCVER 5.5 vara s re nsh afer efarape inp =i 5 ies okaiw i Peieysgae etal as oss (eyes taunt pete ts o/s) ote 557
Milk
analyses, application of the theory of probability to interpretation, address
Py VAPUCSGOM ER ey elon gogo aaps aicincia bi3\0 © 5, c15/ syn Kis cleieym ole. 2ia\qa alos oe erace lalevereiere 14
cryoscopic examination
TECOMMMENA AIO NS | DYPELOPEVE ts sate: «te sues (sj iss (ols) of*) s101%1 segs, ora) exe latchapetataieretorare 484
RE POLED YBELOLEV EES a. oixrc so) 5 <Ioiesc shsiaississaiscc er orcs sisieisiee ste eieesiole etelete mrereiene 470
cryoscopy of
faery (ANE doe aradiotadognoulny Gu geouEsbosonsuoteadduoooce 172
FECOMMEDAATION: DY, FLOLEVEEs = «.<1ep)<'5 20 = eerie tele starereteintstci orsie es ise Pahe ole 173
ape? |h7 DENG 755 ope saweon ns Toe opaEoMnD cnees oer -remueboroo tor 484
Mitchell, J. H., report, inorganic plant constituents...............-.-.+-+-+--- 136
Mitchell, W. L., report, analytical methods for the analysis of silver proteinate.. 542
Mitchell, L. C., report, determination of moisture in cheese..................-- 498
Moisture determination
in cheese
reconbmendations | by, Wiitchells (5 < cis iaejs icra) ora eine eicieici ae areietecetcicinte 506
LE DOLE Va IVIAECHE te eters sts coy asta orep sists cits Stet ofel heaven eae Nous ecetouezelotraretarateays 498
tin Chae itll, parser Lyle Wil OMS ee camera edeubober Scaceeseoaneec edn dar 509
Mold in tomato products, effect of the use of different instruments in making a
microscopic examination, paper by Howard.............2.....-22--0----0es 226
Monobromated camphor in tablets, methods of determination
etarineackyaeyn lary NW int nee ig onion so n.drichibbiadmidr asco ee E Sa eao- 589
RED OR DP Vila Ne oe Sogn opetiecph ender ods oc Sarena COMBE ESSE Sau aase 587
Moore and Caldwell, paper, some results of the determination of potash by the
Lindo-Gladding method using alcohol of various strengths in the presence of
Sa hyn 34 WE A eas dean o ad Seu aOUF Oo e GDC OLD Ste Gu asEeE SCS Sep Cun Beaosnc 136
Morphine, methods of analysis
RECOIMsTE TA OUS YAGI CALC cits crete fle aerate ioral ole) onecare a) olarelnvepeirieielateteie i= 155, 575
REPMALERD VAG IN CALE SP hae ter seey sete ev eheletel a satel ehelelererel heya ape etary =teiela fel otal= 150, 573
Morton, report, fluorides in baking powder........-.--..-.----eee+e sees seer eee 542
Murray, report, determination of
leaolinid mtcqpeoduets | er teers site onsite seatste omaha reel talesialo) nel ale enalol 530
ehloralihydrate in drug: products... sco cis v2 lyse esi ne = sie) yateie hat yao ica 541
ehloroformiyin rite: prod ews << ites =e <a0al +) teleost ele) aie eisai ete 539
Nelligan, paper, limitations of the present official methods of analysis for insoluble
phosphoric acid in dicalcium phospate...........--.-20-2- eee ee cece eee eens 97
612 INDEX TO VOLUME V
PAGE
Nitrogen
availability by alkaline permanganate method, paper by Magruder........ 454
Kjeldahl method and its modifications, paper by Paul and Berry............ 108
recommendations
by CommittestA ac, eRe Oe role he SA aut osarsetuoteeame 329
Ibyithiel psa fF. See ete Siena & tA cievaveita areas avec lod orc RIA Ce 105, 453
reportiby Phelps ois sir. tise tense Alot Biers 5 ee ere a0 RP za eC Ste eS 104, 450
Nominations committee, appointment and personnel......................-- 79, 428
Novocaine (procaine), method for examination
recommendation yby Hanson. ..8 ve ao cree ae eae ee ere eee 166, 593
report iby: Hanson 1.50, a6 isbsissid.oa,s sot eisip eleseiciess ors eeentegale oa MEET 163, 589
Obituary on’ William’ Frear, by R2N: Brackett-- >. +1222 + ce2scteoeemee nee No. 4, iii
Officers, committees, referees and associate referees
for year ending October: 1920 te Neon nj scien ttre oe ee eee i
for:vear ending: October. 1922 x. ose patra, eicests ore sav cisisioiatel arsine ara ETO 352
Oil, sandalwood, recommendations by Committee B.....................0.2-0- 338
Oils, peppermint, differentiation of Japanese and American, report by Eaton..... 597
Oils and fats
changesiinymethods m1. 2321. -5-s ariel Weise ise cael a One site Saco oR Cree 310
recommendations
Dy Committee! Ce ore. dicisweiaeersaavesis & Gienernvale 34 avers ape ee URE a CA eee 346
ya amiesone ss oor. ies 5caisieis avoerestonreidre «ialalaniskee ie ay oc hcaueinle een Eee 512
SINCE oso Sasel neseic tee chtaes i501 d,s/'o:6) 00a <epReieis eclaps alec cete ae ERE eee 179
report
bys JamiesO Dire ans Sete aheicya i napa yetes cape forsvek agence meee arent tel etait oie sient 512
IDYeEQODnedh teens sd aials tole aumiansnetove save sista acs) os vakeerers syens eke ttoteagorans ters acorn 178
Opium, alkaloids of, recommendations by Committee B.......................- 338
Paine; report; saccharine progpcté ns uiree ete o wieis ck neinelee einen isis 78, 429
Patten, report, inorganic plant constituents. .s% s+ +6 +s ince ae eee 467
Ranl; reportyacetylsalicyliciacid netrmecins oiarclery sve) srouastalsis ska esti sieeae eae 581
Paul and Berry, paper, Kjeldahl nitrogen method and its modifications.......... 108
Pectin in fruits and fruit products
recommendations
By Bisbee P2720 5, ..s etree siereyere eietele aioe stale ters uoaaieKoley o Siena ce eee Ree tetcas Tare arene 225
by Committee © saa ie) stave crnveveveret vs svat2t cvaletsl Ofapayarsvetereht ave cokerahersrsherars raters 341
KEPOLE DY BISDEE s Savete woo wiatteelepers, eyctcta siowleiere) dhasissnis isierere: cictcrater OL iotetsh ob pCa 224
Peppermint oils, differentiation of Japanese and American, report by Eaton...... 597
Permanganate, alkaline, method
some experiences, paper by Robinson and Winters................0.+-000- 446
to determine the availability of nitrogen, paper by Magruder............... 454
Phel paireport, MICKO@eDN s; shales ts ieisiclesereieiois Wie Bee nak ele eis foiere: oY ielet eae fe eI RET 104, 450
Phosphates, precipitated
availability of phosphoric acid
FECOMMENGALIONS DY, ELASKITIS pul cicie:<iciaiercve tone o's al siesyiaiciuin ecatecean eee nE 102
TOPOL DY TASKING, 2 0:..s:c%y «vis. nue ote Srv © ¥ > oubparspbcouareboae uae ger cof Cana Totae 97
recommendations
by Gommuittees As... fts ct ays iatriciassWeiolelaters) ofe7s lotorely ieropcheT et overeve Pie ietcteletal Ene 329
Dy Flaskinsis «ies, tees iucmivnou Rakeutiber os statement te Ace beexele ee OR 464
report by Haskins ’...:.scpce swisinwascoists sats oh Beanie lens foiets Eu ksickine canta as COST ae 460
INDEX TO VOLUME V 613
PAGE
Phosphoric acid
commercial composition, paper by Ross, Durgin and Jones, reference........ 464
in precipitated phosphates
recommendations by Haskins. q.... « jatct.fsie aeons Ste de ele alatctacrela fat) te 102
FE POREIDYp ELAS RAIS soya og oot og, cio po} vate. 91 son is, cscsescfeyentiet~i ave os) gl oe EERaa Putters 97
modified method for determination, paper by Clark and Keeler............. 103
vegetation tests on availability in basic slag, report of committee (Haskins).. 317
Phosphorus, determination of extremely small amounts by the official method,
PAPER YW alee tec sercrevecc eich wore tea ena rei stein ere ar aee aycr one HEN see hol eR MN Rote aot 465
Phosphorus and sulfur in the seeds of plants
FECOMMenGa ton) Dyglaatshia Wes ear oct vaha tales iciatee eda oat epee days lala taller 470
report pysleatsha wr .< acini aetndeeciisie ass Besvaboltoshodsabosecobe pas 136, 468
Photosynthetic processes of plants, recent tendencies of research, address by
reside mba hard shay) tesetons jogs obo ateasieieaicisloer she = /=/-se versie ee lare eve levereaate oxeaaiers etovenstege 366
bickerinpyBordeauxi Spray ssipa Den DY; COON sei ereiclere se exci oeeveiciate ister el crelevepebenckecaiene 50
Pills and tablets, camphor determination by the alcohol distillation method, report
Lay YAW GI Se Ge a tian COT Eon O MO CIS RO CELT TOE IEE Ae tere ete anceisted a tah cramic 544
Plant constituents, inorganic
Changes inimethods 5s. 15,5,s:0/e.6.0 6 Oe he eT ee ae oe ete ae te eae 300
recommendations
ya @ommniittee As rire... .cosetave :areta ze ate %s fyrarate otet ot shovarst ora; spans) SSP o stat TG dere 329
Ya WVEttcbre ll eee aposcaisyerays 21s stsns csinlorsrevs.ey siccs 1spe er suntetale Sisvolacsyecsie (le isafelesateiecel arate 136
bys Pattene eh Aes eos) SNe MAINS SISAL Set eee 468
report i
bye Mitcheel lies ctor oiet sy erarcrarsrororobel oth d ciate tala cro le fel aval a Beat dra Sara eyes 136
yp PACECTAS aay oy ctor ater t Ae shay vay sv Shor st akar enn) sf aVov4) yar PYRENEES PA AI ee Tes 467
Plant products, microsublimation
Recommendationi Dy VICNOCVEN. .)< -raysis eccleie sralsiel niece vere -Yrisleraicreleiavshe lay sielevalsyel stars 559
KEPORt DY A VAICUOC VER! feyej0 <0 cieis)se1eleie,slersisicieicy= si sino 0.0) Uabaedarste = eR Maeibele clade yoee 557
Plants
medicinal
recommendations
DyaComimitteed beanies ie ccietctesere sie seusistoss) erste tis Eee FE ae 338
RN AGIOS ee eee oad Sa HOG Oro CC OTD ODED Sau GEUn baasuom oer an are 163
KEPOLE DY VICHOEVEN,« a.c.0: srclessiole!slele viel stelelera s eisl oiels cue eleie wtdaehochalalel ola eDatesieli= 155
recent tendencies of researches on the photosynthetic processes, address by
inizelnela ein cl Bbaron oe Goda 5 OSS aoe TOR oen OBE Odom bad memOOssb bn do ac 366
Polarization of vinegars, paper by Balcom and Yanovsky...........---.++++--- 245
Pot culture tests on the availability of potassium from greensand composts,
maar lay SONS We See soon ea coe sone Here ooroore goeson seeeaann bods dane 133
Potash x
availability
recommendations Dy McGall. oo... 5 oe. ope oe ous ogee nye s:nseneiole)s oye iv wacle) lai 133
REpOLtDyAViC Caller. cicste oe sichajai-feke.e eieisie ele raelevale iene “clei seh) “eo eg teatro tens 132
determination of small amounts by the Lindo-Gladding method, paper by
RIT She SSS CONS COM Dane JU Oe eo Rae n enaobe Heuer Seeibcapnadcase 4 456
KECOMIMENGALIONS DYJH OY aie, sale\e «cai 012 «sisi. wleie) of oi q/s)evelal = elsie) erelel=) telat tee vorene 456
REDO: [SLAG eens on DADE OOO OUD ORDO DOOR OOO OODOnE GOO TDS FAD an SeocG 0.0 ce 456
results of determination by the Lindo-Gladding method using alcohol of
various strengths in the presence of sodium salts, paper by Caldwell and
SSSTANN NRE SRY Pat ayetsya\« sia) Sieistore che of ic 'sjoh ove: ofelo) ois) Svazere iesolslitel sede cfeiad eRe MRT KEL Es rct te 133
614 INDEX TO VOLUME V
PAGE
Power, paper, detection of methy] anthranilate in fruit juices, reference.......... 225
Power-Chestnut method
for the determination of caffeine in coffee. ... 2.0... scene ees ener een eeneecs Dail
for the determination. of caffeine in ‘tea... 2. guialk yeh cecbineeetekebuieie =» - 290
Precipitated phosphates
recommendations
by Haskins: (2/2! S02. SATE eee ORO AE CTU ER ia eee eee Repel 464
by Committee Ase, LEST LAD Be LR Pa ay | eee 329
report by ‘Haskins. eo er sa st ce in see Ce eee De eee eRe Lento eee 460
Prefaceerrata sc) eccrc cae acts ce ee ects Roce eRe re ee ee nee 298
Preparation of a neutral solution of ammonium citrate
recommendations by Robinson. s3.8 Ste tee coe eee oe ree eer 445
report: by /RObINSoM ss .siechs.05/2 ataisjeve cits: steers ar ete le mittens Gk oye noe ean eee 443
President’s address
DY ARLANG sade cenit chee che davate obese hay shevciegs shales Wecs;eiaiepe lice eas n BICLO ee tele 366
DY Vth poe otitis a crepe ate hie siclciyn aren ess, oss duet ete /s/8; ch eterele elem e Gee 14
Preservatives, food (saccharin) recommendations by Committee C.............. 339
Procaine (novocaine) method for examination
recommendation by, Manson: 55.56 sci os eins etereem oe mies eine Oe REE eee 166
report. by Planson acc acuu- cers pcre ciepa cen cs bec CREE 163, 589
Qualitative and quantitative analysis of arsphenamine (salvarsan) and neoarsphena-
mine (neosalvarsan)
recommendations by Hoover and Glycart...............--0eeeeeeees ds culee 529
reportsby Hoover:and, Glycart 5). ...2)20-c.2.chsierecereievoustes suesoveisleley9 (isl Rte eee 525
Quartz plate standardization and normal weight, report (Bates)................. 315
Reagents, chemical, testing
recommendations
Dy Collins: oi is: cal) soso Ocean oO Ise le teh Son fe feel eohepabepelC ele eee 54
Dy. Committee Boo. scic ie cth ea yesese: oeejepsiviee Sueieta 4.0/5 Ie OO URED en 335
report bY Cofling ors. Te lteter cnet alcatel lalcler tet een ea eID RR iat 54
Recent tendencies of researches on the photosynthetic processes of plants, address
by BresidentiHand ci ercijn cies sors espe ie ul nis cranes cateleteldie = este aie Ne ee 366
Recommendations
of committee on methods of sampling fertilizers to cooperate with similar com-
mittee of American Chemical Society, report (Jones).................... 315
of referees, report
by Committee (Ross) 23s seed fo cic eee oe ee cane eae cle teat Sere ene 326
by Committee A: (Ross) 225.02 cases onto brecrnoelhs cick idal seat eee 327
by Committee:B ‘(Ly thgoe) jc usec) 5.5 :aie-aiptogeceig prolyl cos pts aie eee ee eee 333
by; Gomnuttee G (Doolittle) oo yu: . cw suisicre oss pied wens Siete eee ote eet eG 339
Reed
paper, detection. of ground bran in SHOrtG « s..1c,cj::8 vise nis sss) eer enero ate oe 70
report; foodsiand feeding stuliss. 3/0) [cee ees cine See retreated 418
Referees
report
of Committee A on recommendations (Ross)... .......-0c00eeceeeeces 327
of Committee B on recommendations (Lythgoe)... .................055 333
of Committee C on recommendations (Doolittle)..................-... 339
of Committee on recommendations (Ross)...............0.0es0 ee eeeee 326
INDEX TO VOLUME V 615
PAGE
Referees, officers, committees and associate referees
for: yearendingr October yl O20 set ois eve. c los css aris re slotee-21 2s eke eS 1
forjyear, ending October: 1922/27 ob i..0s2 22 Se Ee ee ee 352
Reference; tabless errata. jr. Seo lars wieve,c ls cmos v2a< SRE SA STE ree 299
Resins, gum and balsam, recommendations by Committee B................... 339
Resolutions
committee:appointment andipersonnel. ;. .'<....2.tisses cic Ler RR ee ae 79, 428
reportof committee by) Prear: eis. oe fe Se eee See eee 349
Robinson
paper, determination of total carbon dioxide in baking powder.............. 182
report, preparation of a neutral solution of ammonium citrate............ 92, 443
Robinson and Winters, paper, some experiences with the alkaline permanganate
HERETO ae osc) is!e yore sn: oh STRSTR e Se, SE SEAS INS Tale, are ela aN AIS AAO 446
Robusta coffee, paper by Viehoever and Lepper...............00.eceeeeeeeees 274
Ross, B. B., report
of committee on recommendations of referees..............0020000000eeees 326
of committee A on recommendations of referees.................-022--0005 327
Ross, W. H., report, determination of boric acid in fertilizers and fertilizer ma-
CELIA GEE Ta ee LV AGAS & ois Soars joins. sia eto oose ete chal evethiate, AREOIS ROSE EL RRL ON 80, 440
Ross-Deemer method for the determination of boric acid in fertilizers............ 327
Ross, Durgin and Jones, paper, composition of commercial phosphoric acid, refer-
NCE. ETT OE EY -IS Tae: fate SRR S ted cea tale SiMe cles sas aaa contend. atanyavel. alt 464
Saccharin, food preservative, recommendations by Committee C................ 339
Saccharine products
Ghangesanwmethods sare. sore sesh bean sek eS ees tele TOs be 305
recommendations by Committee By oo. sec ee beens Cees eee tee ee 334
FEPOLEDY Paine. fa sees css is aa bs a dieed ane adaed Lata ee Te eee ee 78, 429
Salad dressings and their analysis, paper by Lepper.................20..--005- 248
Salevreporeawater eee e cs sass Ged hea I A RI PSA UE POON Ss 29, 379
Salvarsan and neosalvarsan, qualitative and quantitative analysis
recommendations by Hoover and’ Glycart.) 5... ..- ce eee ee 529
KEpontapyaLlooveranGGlyCantic: secs -\siei state oe sievs a incee sil Stele aetna omer tae 525
Sandalwood oil, recommendations by Committee B...............000 0c eevee eee 338
Santalol in santal oil
estimation by the assay method of the U. S. Pharmacopceeia and by the dis-
tillatrontmethod report by; Harrison: 2.05. ccc r elt cae conc snc otelsie eeeeiene 545
study of the distillation method for estimation, paper by Harrison.......... 166
Secretary of Agriculture, address by Meredith...................0000ee ee eeeee 238
Secretary-Treasurer, report for year ending November 17, 1920 (Alsberg)........ 318
Seeds of plants, sulfur and phosphorus determination
recommendation iby, Watshaws: 2.222222 4 tet ve soe se eerie nel eecine 470
meee [oy LEGA TE Tab vc od HOO HCU EICIIE COIS DED A ia Acree c.coh aOR coo Dict 468
Seidenberg, paper, modified procedure for the determination of the ‘‘turbidity
IOINE HOLMDEL EE MAE te trees cikeniats a nie 4s Gin Gieres Sea elem Seiae iat thom tae eteltrete, lave 512
Separation of meat proteins, recommendations by Committee C...............- 343
Shell in cacao products
BADETAD VAT DELDELR retiree cise cite holes ole ae aisieicratel ove iso o\oeleipl= ia) sheretalmvedsinge 260
recommendations
yACommittec) Ganiran 7 > csp nine ee ts laicte aieiolereitereielets ree teyaiel pet» 347
byaglien berinera)-1 0) lara cto vctal ay dictation a aicie alerctetern ts tee re eee feleroteralel)« 259
616 INDEX TO VOLUME V
PAGE
Sherwood, report, detection of artificial invert sugar in honey................... 429
Shorts, detection
ofjadulteration; paper by: Bisbee...) «2. vacuaseeeh cee een eee ee 74
of/ground|bran,;paper'by. "Reed! 2) <n) less es aes to) RE LL ee 70
Silberberg,
paper, cacao products with special reference to shell content................ 260
report, stock feed ‘adulteration... |...) beeeniteg bee Deere eee 77
Silver proteinate, analytical methods
recommendation by Mitchell ic, stialeionswiniesiemien rey ot nie eee ae a 543
report by, Mitchellluxegntitvad odatincety chek Met den, aed ees ee eee 542
Smith, paper, pot culture tests on the availability of potassium from greensand
COMPOSES SERIA. NAL aoa aetais. tate Me, MUNORER TSO... Ae: RIES ELAS Pe 133
Soft drinks (bottlers’ products), recommendation by Committee C.............. 342
Soil analysis, report of committee on revision of methods (Lipman).............. 316
Soils
recommendations
by ‘Committeé.A.. 2. ..,... eatin. Us SiGe eter tice 0. Ace RE ROO 332
byMacintire: .xsariiven. at Jstok. acne. de. POURED . TINE oy ee 53, 417
FEPOrt Dy, acl aeire 25 ai sha oi anncoiel aiaicrassisuacel oars wicks aca HOSE ee eee a eee eee 52, 405
Some experiences with the alkaline permanganate method, paper by Robinson and
Winters: 2200 Sedseieks fateeneh. be sapiens ORS se ee 446
Spears, paper, boric acid for neutralizing ammonia in nitrogen determinations.... 105
Spices
and drugs, volume weight determinations
recommendations by Vielioever.. o..5.. 0: 0.- ++ «+s ce - se ovate eee 557
TEPOLE Dy VIEHOS VER! hv. e's 's5 sce devon e bie Sree eae eset, OR een 553
and other condiments
changes in; methods 3., ./,¢ «js. «saci gs) qa nie anette os tN ase OTe 310
recommendations by, Gommittes) © o.4 mince cerned eee he eee ee 346
Sprays, Pickering’ Bordeaux, paper by Gook.........-..--..:.-.. «esses oe 50
Standardization of quartz plates and normal weight, report (Bates)............. 315
Stock feed adulteration
recommendations
by: Committee Bs. s) .rats-.hd Sh Sens se eat hae RE RT ea iad 334
Dy Gensler sics.ou' cies pldbeeave. bain aie. cinlavoiedig peeis @er elon 0 ene 428
by Silberbergitasrcasrsrgdlh wed t ete he Posdrant dasa oe See ate 78
report
by Genslety srr 88 datos aid aparse eaae eee se ne eee ee 424
by Silberberg... s'2cos nestle ss hieeTOnE ya bb o. Weel eRe Ce Ceram 77
Sugar
artificial invert, detection in honey, report by Sherwood..................+ 429
recommendations by ‘Committee’, .....). +i: </> + «/wienstutac ie crak: Gi ceetone nen 334
Sugar-house products
recommendations
DY. Brewster :<ccte¥ ds icactelote acafetbys.s uw acclelo Oa puata e's Sea Sheen ee a 437
byGommittee:B ia wrestsanrel wet ince taiatuevin anes xt be reales 334
report Dy Brewster. cis oc cit.0-d sie. 0 aserokayers 4 aPetsretwielore,s. 0:06 9 ohe Ga EMER ale 437
Sulfur
and phosphorus in the seeds of plants
recommendation by: Latehaw:s sic s +< cosas «o's oabentl Unie rete ote 470
report: by Latah awa. .sipsainoitisyprewinictaorineeh sla: 010s, Sia op Sie Rete 136, 468
report: Dy, MacIntire:s.sisisec:aniaavepey Fineiee'oiny ob ar sce os cig 5 Re ae 418
INDEX TO VOLUME V 617
PAGE
Synthetic drugs
recommendations
Paya COMMU ELCORE ceteers sere aYord eo, 2 2) aici sisrovsters scarssaseinva Whig olsle eee meleetone CLEATS 337
VS ED Caw ater secre sapere) sstn''sca ase,» Syevevsde ore levi (ay ste lovel Se leveveis oa Cae ge ovate 150
ROT IORCAD Yam V VANE EL CoN Bete Ye feter in) ofc fo feels sve ianovels sosicte le cererclnvnrs eyeeve eth teiatadereiele eres 150
Taber, report, determination of shells in cacao products..............2-.+-+000: 253
Tablets and pills, camphor determination by the alcohol distilladon method,
TEDOLAD VA MMMICL eS ea ete elasevereiCieiels + nieis.x side te siqja eave se ele je SQieeteesteeie mites 544
Tanning materials and leather
TECOMNIMEHUACI ONS Da V CLCCM s c2ioie clare ci sisicis,svorai ciovsfers:s sais a oteletorcleretererale ctoleya chelate 391
EE POL D Yq V CLEC Mite arias elec crete tere oo sle 6 'a lets. ci. cle is 2 as/ssiele t vie slevsisielsicug sfepersiels 32, 388
Tea
recommendations
pypbatleyserreetre cee ere siere cel sie sate nicin%e vain: « crarcisy ola etchevovetate leyeretensienctetetate 293
bys Committeel Gane. te cyeyeerkesisiisjo20es Sie> S2rsts pee eaie a sprenlase depp hchays 348
LEPOLt DA alley mere ele o elas feieFels:s 0: 5:0:' ya, e4s's. # sie sustels(eiaysieielore sre. [elstetel otere lolefe 288
pleasNchanpespimymetnoasyreteie article <=) is: ctete cle sci e chersiel~ avsiefaselevenslaverey s/etaieralsievate 311
Testing chemical reagents
recommendations
isyy Caaimnngies 12) dog doo pus oobDe BuO oan SO nomboracgntieonponcoooanods 335
iy CoG snc hondus conosco EOS ene OD AULD CROGBEDDeODsEpoSeTD ogo occ 54
EC POLE Va COMMS ee eres ctela cic aie ais) orale! ote 5) ofo/e is igs =) =o olay fot alate] ate sonenelePatetol 54
Tomato products, effect of the use of different instruments in making a microscopic
examinatiousfor mold. paper, DyZHOwald «| ./2\<.< [<6 o.0:s o1sie:sicisl elvis alain yetal=|aieie sieie «nie 226
Treasurer, report for year ending Nov. 17, 1920 (Alsberg).........-.....-.0005- 318
“Turbidity point’’ of butter fat, determination, paper by Seidenberg............ $12
Turpentine
Tecommendationiby) Clarke: viacrai-}oj- 501s o/0.« 9 seis ais vieisiai= = s%e ste «)elela|ele/aloleis,-i=\ciels 551
EE DOLD VEC lake se paeee PAs ee te ais icroteiaie eis rete lee a io etorsvsvoielere/elevereleteral=f-deistslelers 547
Vegetation tests on the availability of phosphoric acid in basic slag, report by com-
PUGS (CRESS). sh4ohwoa dboce bots aceon DOEEReO SoS Ob cddoaue bongo coomnut 317
Veitch, report, tanning materials and leather..............---.0eeeeeeeeeees 32, 388
Viehoever, report
identification of crude drug substitutes. ..........-..s0e eee e reese eee eee 560
MIGGHeET METS. 2 goemod Cosa de Leto oO Opodo oUeceDud oc ocrobrSonenms an 155
microsublimation of plant products........---- ++ -+++ eee e cere cree eee eeee 557
volume weight determinations of crude drugs and spices............-.---++ 553
Viehoever and Lepper, paper, Robusta coffee. .....-.-..----2eeeeee eee eee ees 274
Vinegars -
Ghampestimy met hodspysiersiavete sist (a)cie/+10/eler<crale = ejeleimie © «/-ln\= ci ahesepeiaie/oie|=/elsiein*le\e\=)= 308
polarization of, paper by Balcom and Yanovsky.........-.-+--++++s+++05> 245
recommendations by Committee C.......-.-.. 2. eee eee eee e cece eens 342
Visitors and members
AEM OD OS INECEIN Gee tetas cicis vier <= (= /ai0i=\e2)n\2)=)as>|obells 2) =1=!=1241nie)a/«i0]e{ele/mivin aii serels 8
ai? TOD TTGEEINGS 4 o ce obob oo DA OEDe Doone ODDO J0ec en eapo Uo oMeDDOGOUUnONoC 359
Volume weight determinations of crude drugs and spices
recommendations by Viehoever........---+.++2+2 cece cree eet e teen eens 557
report by Viehoever. ......-.2...secc eee e eerste eee tenet enter nsec nn ees 553
618 INDEX TO VOLUME V
PAGE
Water
in foods and feeding stuffs, recommendations by Committee B.............. 334
recommendations
by, ‘Committee Ac, cit viat re cies ee ee ea aCe ace oe ERE eee 330
Dy Salle overs ascicte sin sitratsieveascustee cette aeetion oreo ete COCR OT enee 387
TEPOLt byzoale:e ewer Leb aeaee gf eee ence eae ancien ne 29, 379
Waters, changestin;methods 27... se acine ine aoe Risen ain: Mee eee 301
Wiley, OW. bonoragy, president. addressraee rice sn ee een eee ce eeeeteie 229
Wiley, R. C., paper, determination of extremely small amounts of phosphorus by
theofficial method oye tcite cise felt eeecetee orc oce OER RICE: Gece eCee 465
Winters and Robinson, paper, some experiences with the alkaline permanganate
THECNOG ME Me ya tiautstencratias erst scene ei evele ae Pcie crete Chere ee Ra Eat ee 446
Wright, report
methods for determination of monobromated camphor in tablets.......... 587
synthetic drugs sr. oetoe sitefaore os eters Sestel ie UN ole ee RIS Oe oe CoE EEE EREE 150
Yanovsky and Balcom, paper, note on the polarization of vinegars.............. 245
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