Distribution of the principal cannabinoids within bars of compressed cannabis resin

Determination by gas chromatography-mass spectrometry, after extraction into hexane, of the relative amounts of the three most abundant cannabinoids, cannabidiol (CBD), Δ9-tetrahydrocannabinol (Δ9-THC) and cannabinol (CBN), and the six next most abundant compounds in cannabis resin all showed significant variations in their relative amounts with sampling position. Thus, data from a single sub-sample cannot be regarded as characteristic of a cannabis resin bar or without further evidence of coming from a particular resin bar or batch of bars. A cannabis resin bar stored under ambient conditions for 12 months showed major loss of Δ9-THC and an increase in CBN content as well as variations in composition with sampling position.