June i6,1923 
Determination of Nicotine 
963 
tions, IS sometimes a long, tedious procedure; and, if not so conducted, 
will often give inaccurate results on tobacco. Accordingly, il was thought 
possible to substitute an ether extraction of the sample for the steam 
distillation of it in the silicotungstic acid method, in order to ob¬ 
tain the nicotine for precipitation. Afterwards, the nicotine could be 
extracted from the ether by acid and determined in the manner pre¬ 
scribed in this method. Accordingly, considerable work has been car- 
ried on with this in view, and, after many preliminary determinations, a 
method has been devised which has usually been found to be more rapid 
than either of the official methods and, with some samples at least, gives 
more accurate results than the silicotungstic acid method unless the'latter 
is carried on under carefully controlled conditions. It combines the good 
features of both official methods and eliminates an undesirable one com- 
mon to both, namely, the steam distillation. The method is as follows: 
REAGENTS 
Alcoholic sodium hydroxid solution: Dissolve 6 gm. of sodium hydroxid 
in 40 cc. of water and 60 cc. of 90 per cent alcohol. 
Silicotungstic acid solution: Prepare a 12 per cent solution of the 
silicotungstic acid having the formula 4H2O, SiOj, 12WO3, 22H,0. 
(There are several silicotungstic acids. The acids 4HjO, SiOj, 10WO3,. 
3HjO and 4H3O, SiOj, 12WO3, 20H2O, do not give crystalline precipi¬ 
tates with nicotine and should not be used.) 
Ethyl ether of quality equal to U. S. P. concentrated. 
Dilute hydrochloric acids (i to 4) and (i to 1,000). 
determination 
Weigh I gm. of tobacco extract (high grade 40 per cent) or more of 
extracts containing less nicotine; or 5 gm. of finely powdered tobacco 
which has been prpiously dried at room temperature or slightly above, 
to permit powdering, and put into a beaker or, preferably, a porcelain, 
dish. Add 2.5 cc. of the alcoholic sodium hydroxid to the tobacco pow¬ 
der or about 5 cc. to the extract; it is necessary that enough alcoholic 
sodium hydroxid be added to liberate the nicotine. Follow in the case 
of extracts with a sufficient quantity of pure powdered calcium carbonate 
to form a moist but not lumpy mass. Mix thoroughly with a pestle or 
spatula, transfer to a suitable container in a Soxhlet extractor and ex¬ 
haust for about 5 hours with ether. (Probably another solvent could be 
substituted for this purpose.) It is important that the temperature of 
the cooling water during the extraction should not be much over 20° C., 
and sufficient solvent should be used in order that its volume in the 
extraction flask should never be less than about 25 cc. After the 
extraction is made, the exhausted sample is removed and the excess of 
ether recovered, but the volume of ether extract should not be permitted 
to go below the above minimum or more if necessary to keep the ex¬ 
tractive matter in solution at ordinary temperature. (If the tempera¬ 
ture of the cooling water is too high and the volume of solvent in the 
flask becomes too low during the extraction, there may be a ■gnigll loss 
of nicotine from samples of high percentage.) 
The ether extract is transferred to a separatory funnel, preferably 
with a short stem, the extraction flask washed with a little ether and 
finally about twice with hydrochloric acid (i to 4) to remove all nicotine. 
