Development and validation of a quantitative method for the analysis of delta-9-tetrahydrocannabinol (delta-9-THC), delta-8-tetrahydrocannabinol (delta-8-THC), delta-9-tetrahydrocannabinolic acid (THCA), and cannabidiol (CBD) in botanicals, edibles, liquids, oils, waxes, and bath products by gas chromatography mass spectrometry (GC/MS).

Abstract

A quantitative gas chromatography mass spectrometry (GC/MS) method was developed for delta-9-tetrahydrocannabinol (delta-9-THC), delta-8-tetrahydrocannabinol (delta-8-THC), tetrahydrocannabinolic acid (THCA), and cannabidiol (CBD) in matrices including plant material, liquids and oils, waxes, edibles, and bath and body products. Samples were prepared by homogenization, extraction of the cannabinoids into solvent, liquid/liquid extraction, and derivatization. The GC/MS method was validated from 0.15% to 5.00% (weight basis) to encompass the 0.3% legal distinction between hemp and marijuana. Validation was performed assessing imprecision/bias, calibration model, recovery, interferences, limit of detection, matrix matching, carryover, accuracy, and an assessment of CBD conversion to delta-9-THC. The calibration curves were quadratic weighted 1/x with r2 > 0.990. The method had a detection limit of 0.075% in plant material for each analyte. Analyte recovery was greater than 70% in plant material. Carryover was not observed up to concentrations equivalent to 100% analyte, and no forensically significant conversion of CBD to delta-9-THC was observed. One cannabinoid isomer, 9(R)-delta-7-tetrahydrocannabinol (9(R)-delta-7-THC), was determined to interfere with the quantitation of delta-9-THC, but could be differentiated based on mass spectrum. The method was determined to be suitable for quantitation of delta-9-THC, delta-8-THC, delta-9-THCA, and CBD and was able to differentiate hemp samples from marijuana samples.