Development and validation of a Fast gas chromatography/mass spectrometry method for the determination of cannabinoids in Cannabis sativa L

Abstract

A routine method for determining cannabinoids in Cannabis sativa L. inflorescence, based on Fast gas chromatography coupled to mass spectrometry (Fast GC/MS), was developed and validated. To avoid the decarboxylation of carboxyl group of cannabinoids, different derivatization approaches, i.e. silylation and esterification (diazomethane-mediated), reagents and solvents (pyridine or ethyl acetate), were tested. The methylation significantly increased the signal-to-noise ratio of all carboxylic cannabinoids, except for cannabigerolic acid (CBGA). Since diazomethane is not commercially available, is considered a hazardous reactive and requires 1-day synthesis by specialized chemical staff, silylation was used along the whole validation of a routine method. The method gave a fast (total analysis time < 7.0 min) and satisfactory resolution (R > 1.1), with a good repeatability (intraday < 8.38%; interday < 11.10%) and sensitivity (LOD < 11.20 ng/mL). The Fast GC/MS method suitability for detection of cannabinoids in hemp inflorescences, was tested; a good repeatability (intraday < 9.80%; interday < 8.63%), sensitivity (LOD < 58.89 ng/mg) and robustness (<9.52%) was also obtained. In the analyzed samples, the main cannabinoid was cannabidiolic acid (CBDA, 5.19 ± 0.58 g/100 g), followed by cannabidiol (CBD, 1.56 ± 0.03 g/100 g) and CBGA (0.83 g/100 g). Δ9-tetrahydrocannabivarine (THCV) was present at trace level. Therefore, the developed routine Fast GC/MS method could be a valid alternative for a fast, robust and high sensitive determination of main cannabinoids present in hemp inflorescences.