Constituents of Erythroxylon coca. II. Gas-chromatographic analysis of cocaine and other alkaloids in coca leaves.

A gas-chromatographic procedure is outlined for the analysis of cocaine and cis- and trans-cinnamoylcocaines in coca leaves. The procedure was applied to the determination of these alkaloids in coca leaves collected from three different locations in Peru. The extraction of alkaloids from plant material was accomplished following the procedure we previously outlined. Recovery of cinnamoylcocaines was quantitative and the average coefficient of variation was 6.8%. Using androst-4-ene-3,17-dione as the internal standard, the correlation coefficient (r2) as determined from the calibration curve of trans-cinnamoylcocaine was 0.99 and the response factor 0.72. Observable differences in relative proportions of cis and trans isomers of cinnamoylcocaine were found among samples from different locations. In addition, the relative proportions of the total cinnamoylcocaine concentration to cocaine varied with sample origin. We have also examined coca extracts using a nitrogen detector and by gas chromatography--mass spectrometry. The nature and identity of other nitrogenous peaks in the chromatograms are also discussed.