Comprehensive cannabinoid profiling of acid-treated CBD samples and Δ⁸-THC-infused edibles

Δ⁸-Tetrahydrocannabinol (Δ⁸-THC) is increasingly popular as a controversial substitute for Δ⁹-tetrahydrocannabinol (Δ⁹-THC) in cannabinoid-infused edibles. Δ⁸-THC is prepared from cannabidiol (CBD) by treatment with acids. Side products including Δ⁹-THC and other isomers that might end up in Δ⁸-THC edibles are less studied. In this paper, three orthogonal methods, namely reversed-phase (RP)-UHPLC-DAD/HRMS, normal-phase/argentation (silica-Ag(I))-HPLC-DAD/MS, and GC-FID/MS were developed for analysis of cannabinoid isomers, namely Δ⁸-THC, Δ⁹-THC, CBD, Δ⁸-iso-THC, Δ⁽⁴⁾⁸-iso-THC, and hydrated THC isomers. Eight acid-treated CBD mixtures contained various amounts of Δ⁸-THC (0–89%, w/w%), high levels of Δ⁹-THC (up to 49%), Δ⁸-isoTHC (up to 55%), Δ⁽⁴⁾⁸-iso-THC (up to 17%), and three hydrated THC isomers. Commercial Δ⁸-THC gummies were also analyzed, and issues like overclaimed Δ⁸-THC, excessive Δ⁹-THC, undeclared Δ⁸-iso-THC, and Δ⁽⁴⁾⁸-iso-THC were found. These findings highlight the urgency of improving regulations towards converting CBD to Δ⁸-THC for use as food ingredients.