Determination of cannabinoids in cannabis products using liquid chromatography–ion trap mass spectrometry

A method was developed and validated for the simultaneous determination of five cannabinoids, viz. cannabidiol (CBD), cannabidiol acid (CBD-COOH), cannabinol (CBN), Δ9-tetrahydrocannabinol (THC), and 3′-carboxy-Δ9-all-trans-tetrahydrocannabinol (THC-COOH) in cannabis products. The cannabinoids were extracted from the grinded cannabis samples with a mixture of methanol–chloroform and analysed using liquid chromatography with ion-trap-mass-spectrometry (LC–IT-MSn). For quantification the two most abundant diagnostic MS–MS ions of the analyte in the sample and external standard were monitored. For confirmation purposes the EU criteria as described in Commission Decision 2002/657/EC were followed. Fully satisfactory results were obtained, that is, unequivocal confirmation according to the most stringent EU criteria was possible. The limits of quantification were 0.1 g/kg for CBD, 0.04 g/kg for CBD-COOH, 0.03 g/kg for CBN, 0.28 g/kg for THC and 9.9 g/kg for THC-COOH. The repeatabilities, defined by R.S.D., were 2% for CBN, THC and THC-COOH at the concentration levels of respectively 0.023, 3.3 and 113 g/kg and 5% for CBD-COOH at the level of 0.34 g/kg (n = 6).