The extraction and estimation of the cannabinoids in Cannabis sativa L. and its products

Abstract

A convenient method for the complete extraction of the cannabinoids from fresh plant material, herbal cannabis, cannabis resin and reefers, has been devised. Chloroform was a more suitable solvent than light petroleum or ethanol and simple shaking of powdered material with the solvent was effective. Fresh material should be air-dried and powdered before extraction. The main cannabinoids in the extract are determined by g.l.c. using androst-4-ene-3,17-dione as internal standard. The coefficient of variation for repeated determinations of THC on a single extract was 1.4%; for all operations, including sampling and extraction, it was 2.7%. Duplicate analyses of 24 samples of herbal cannabis and of 20 reefers, all of varying potency, showed that the errors fell within the expected limits for THC, CBD and CBN. The method is simple and rapid; duplicate determinations can be completed in about 2 1/2 h.