Determination of the distribution of cannabinoids in cannabis resin using high performance liquid chromatography

A high performance liquid chromatographic system is described for the separation of cannabinoids, which were detected by ultra-violet absorption at 220 nm. The identity of the cannabinoids was established by comparison of retention times with reference compounds, by simple chemical conversions to other known cannabinoids, and by mass spectrometry after isolation by preparative chromatography. Cannabis resin from Pakistan and Lebanon was examined for the presence of these cannabinoids. A study of the uniformity of distribution of cannabinoids in individual resin slabs was made by taking a total of 68 samples from 4 different slabs. The variations in cannabinoid content between slabs was measured by 85 different slabs. The validity of these measurements, to determine a common origin of resin for forensic purposes, was tested using resin obtained from 94 different law enforcement seizures.