INSECTICIDES AXD FL'XtUCIDES

307

solution and the nicotine separated by steam distillation. The
nicotine in the distillate is titrated with a standard acid as follows :

CH

-CH9

HCji

HC*

C

HCi

+ HC1-

CH

N

CH8

CH2

HC

Determination of Kicotfne.—Prepare the following solutions:
(a) Alcoholic Sodium Hydroxide Solution.—Dissolve 6 gm of sodium hydrox-
ide in 40 cc of water and 60 cc of 90-per cent alcohol.
(b) A pproximaiely tenth-normal sodium hydroxide solution, not standardized.
(c) Tenth-normal sulphuric add, accurately standardized against pure
sodium carbonate (see pages 5S et seq, Part I).
Weigh into a 50-ec beaker, 5 to 6 gm of tobacco extract or 20 gm of
finely powdered tobacco or tobacco waste which has been dried at 60°.
Add 10 cc of alcoholic sodium hydroxide and, in the case of tobacco extract,
follow with enough shredded filter paper to form a moist but not lumpy
mass. Mix thoroughly, transfer to a continuous extractor (page 146)
and extract for about five hours with ether. Evaporate the ether at a low
temperature and take up the residue with 50 cc of sodium hydroxide (b}.
Transfer the residue by means of 200 cc of water to a 500-cc Kjeldahl flasks
add a piece of pumice or a small amount of crushed porcelain and a small
piece of paraffine, heat to boiling and distill by steam, passing the distillate
through a condenser cooled by a rapidly flowing current of water. Distill
from 400 to 500 cc, stopping the current of steam and using a flame under
the flask at a point such that only about 15 cc of the liquid finally remains
in the flask. Titrate the distillate with tenth-normal sulphuric acid, using
methyl red as an indicator. Calculate the per cent of nicotine in the
sample.