The Identification of Synthetic Impurities in a Vape Pen Containing Δ9-Tetrahydrocannabiphorol Using Gas Chromatography Coupled with Mass Spectrometry

Δ9-Tetrahydrocannabiphorol (Δ9-THCP, THCP) a psychoactive cannabinoid recently found in Cannabis sativa L., is widely used as a legal marijuana substitute. THCP is encountered in sprayed Cannabis, edibles, and vape liquids. The distributors of such products claim that the THCP in use originates from a natural source. The legal status of this substance varies from country to country. THCP and similar cannabinoids with a dibenzoyprane structure have been banned in Switzerland since October 2023. A vape liquid, which contains 90% THCP and 10% terpenes according to the distributor, was analyzed by gas chromatography coupled with mass spectrometry (GC-MS). Besides CBP, CBDP, Δ9-THCP and Δ8-THCP and some terpenes, other compounds were found which probably result from a synthetic procedure. This sample contained 5-heptylresorcinol, the heptyl homologue of olivetol, a common precursor for the synthesis of tetrahydrocannabinol (THC). Bisalkylated compounds (m/z 476) were found as a result of the reaction of one equivalent of 5-heptylresorcinol with two equivalents of (+)-p-mentha-1,8-dien-4-ol or another precursor. Similar bisalkylated compounds are known as undesired side products of the synthesis of THC. The sample contained unidentified isomers of Δ9-THCP, presumably abnormal cannabinoids (abn-Δ9-THCP; abn-Δ8-THCP) and iso-cannabinoids (iso-THCP). Chiral derivatization with Mosher acid chlorides revealed that the Δ9-THCP in the sample was enantiopure.