The
same process serves on the small scale for the valuation of coca
leaves. 100 grms. of coca leaves are digested in a flask with 400 c.c.
of water, 50 c.c. of 1/10 NaOH (10 grms. of NaOH in 100 c.c.) and 250
c.c. of petroleum. The flask is loosely covered and warmed on the
water bath for two hours, shaking it from to time. The mass is then
filtered, the residue pressed, and the filtrate allowed to separate in
two layers. The oil layer is run into a bottle and titrated back with
1/100 HCl (1 grm. of HCl in 100 c.c.) until exactly neutral. The
number of c.c. of hydrochloric acid required for titrating back
multiplied by 0.42 gives the percentage of cocaine in the sample. The
following are some of the results with different samples of coca
leaves of various age:
Contained per cent.
of Cocaine.
Coca leaves from Mapiri, 1 month old 0.5% \
" " " Yungas " " 0.5% |
" " " Mapiri and Yungas |
6 months old 0.4% | Of the
" " " Cuzco (Peru) |_ weight of
6 months old 0.
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