June i6,1933 
Determination of Nicotine 
967 
contained in the small volume necessary to liberate the nicotine, and 
forms a volatile product or products which are found in the distillate, 
precipitate with the reagent and affect the results. Further work will 
be done to determine, if possible, the nature of this reaction. 
The following precautions are therefore necessary in the distillation: 
(i) Use the minimum amount of alkali necessary to liberate all the 
nicotine; (2) keep the volume of liquid in the flask at about 15 to 25 cc. 
to facilitate the distillation of the nicotine; (3) continue the distillation 
until a few cubic centimeters of the distillate shows no opalescence when 
treated with a drop of dilute hydrochloric acid and a drop of the silico- 
tungstic acid. Under such conditions, however, a large volume of distillate 
will sometimes be obtained, as shown in Table III. 
Table III .—Percentage of nicotine in tobacco {moisture free); effect of different amounts 
of NaOH in distillation of 5 gm. sample on the volume of distillate necessary to liberate 
the nicotine. 
No. 
3 gm. 
NaOH. 
Volume of 
distillate. 
Pinal test for nicotine. 
Less 
than 2 gm. 
NaOH. 
Volume of 
distillate. 
Pinal test for 
nicotine. 
61469 
7 - 55 
900 
Absent. 
‘ 7 - 38 
I, 500 
Absent. 
> 7. 29 
I, 500 
Do. 
^ 6. 90 
2, 900- 
Do. 
61537 
6- 33 
900 
.do. 
^ s. 67 
I, 800 
Present. 
5 - 98 
2, 400 
Absent. 
80073 
7-85 
I, 800 
.do. 
^ 6. 76 
I, 000 
Do. 
7-83 
I, 800 
.do. .. 
^6. 65 
I, 000 
Do. 
80144 
^ 7. ^2 
2, 100 
Present. 
^ 7 - 51 
2, 700 
Absent. 
1 NaOH used in distillation, 0.25 gm, 
2 NaOH used in distillation, 0.15 gm. 
DIRECT PRECIPITATION OP NICOTINE 
It was thought that it might be possible with some extracts, provided 
no interfering substances were present, to make a direct precipitation of 
the nicotine and thereby eliminate the distillation and ether extraction 
necessary in the other methods. Experiments were made, therefore, by 
taking a weighed sample of extract, diluting it to a definite volume and 
directly precipitating the nicotine in an aliquot with the reagent in the 
manner prescribed in the improved method as to volume, acidity, and 
handling of the precipitate. While the precipitates were often colored, 
very satisfactory results were obtained on most of the extracts, although 
precipitable matter in others proved to be detrimental. The results 
obtained are given in Table V. 
This method was also tried on tobacco by making an aqueous or weak 
akaline extraction, filtering and using an aliquot as described in the 
preceding paragraph. It was not found applicable, however, as shown 
by the determinations below, on two samples from Table III. No. 61469 
gave 9.13 per cent nicotine by an akaline extraction and No. 61537 gave 
7.53 per cent by an akaline and 7.37 per cent nicotine by an aqueous 
extraction. 
