74 METHODS FOR THE ANALYSIS OF URINE
To express the result in percentage of 80s simply divide the value of x, as just determined, by the quantity of urine used.
INORGANIC SULPHATES1
Foliris Method
Procedure.—Place 25 c.c. of urine and 100 c.c. of water in a 200 to 250 c.c. Erlenmeyer flask and acidify the diluted urine with 10 c.c. of dilute hydrochloric acid (1 volume of concentrated HC1 to 4 volumes of water). In case the urine is dilute 50 c.c. may be used instead of 25 c.c. and the volume of water reduced proportionately. Add 10 c.c. of 5 per cent barium chloride slowly, drop by
I drop, to the cold solution and from this point proceed as indicated in
the method for the determination of Total Sulphates, page 73.
I Calculate the quantity of inorganic sulphates, expressed as 80s,
in the twenty-four-hour urine specimen.
j Calculation.—Calculate according to the directions given
I under Total Sulphates, page 73,
t
ETHEREAL SULPHATES2
I
I Foliris Method
I Principle.—The inorganic sulphates are removed with barium
j chloride and the conjugated sulphates then determined after
I hydrolysis.
I Procedure.—Place 125 c.c. of urine in an Erlenmeyer flask of
i suitable size, dilute it with 75 c.c. of water and acidify the mixture
| with 30 c.c. of dilute hydrochloric acid (1 volume of concentrated
HC1 to 4 volumes of water). To the cold solution add 20 c.c. of
a 5 per cent solution of barium chloride, drop by drop. Allow the I • mixture to stand about one hour, then filter it through a dry filter
| paper. Collect 125 c.c. of the filtrate and boil it gently for at
I least one-half hour. Cool the solution, filter off the precipitate of
BaSC>4, wash, dry and ignite it according to the directions given
on page 73.
1 Folin: Jour. Biol. Chem., 1905, 1, 131.
2 Ibid.