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.