Cannabinoids Tetrahydrocannabinol, Cannabinol, Cannabidiol, Tetrahydrocannabivarin and 11-nor-9-carboxy-∆9-THC in Hair

The cannabinoids tetrahydrocannabinol (THC), tetrahydrocannabivarin (THCV), cannabidiol (CBD), cannabinol (CBN) and (-)-11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH) were determined in 4,773 hair samples. Confirmation of THC-COOH was by GC-MS-MS (gas chromatography--mass spectrometry-mass spectrometry). Confirmation of THC, THCV, CBN and CBD was by LC-MS-MS (liquid chromatoraphy--mass spectrometry-mass spectrometry) on an AB Sciex QTRAP 6500+ LC-MS-MS. The purpose of this work was not to utilize any analyte other than THC-COOH as indicative of ingestion, but to assess the absence or presence, and relative concentrations, of the other cannabinoid analytes in hair of marijuana users vs. primarily CBD users. In this regard, 10% of samples contained significantly higher concentrations of CBD relative to THC than the other 90%. A concentration of CBD that is five times greater than that of THC was proposed as good evidence of primarily CBD ingestion. THC concentrations in the samples ranged from below the limit of detection (5 pg/mg) to 47,808 pg/mg hair, varying widely in the relationship between parent THC and the metabolite THC-COOH. CBN was present in most samples, but concentrations relative to THC decreased with increasing THC concentrations. Only 26% of the samples contained THCV detectable by the method. When present, THCV concentrations averaged 1.77% of THC. A limitation of this study is the lack of subject histories to determine the types and amounts of products used and the mode of ingestion. Also, not all THC from external contamination may be removed. Nonetheless, the data provide a useful guide as to what cannabinoids may be found in hair, at what concentrations and under conditions of marijuana use vs. likely primarily CBD use.