A rapid and simple procedure for the determination of cannabinoids in hemp food products by gas chromatography-mass spectrometry

A rapid and simple procedure using liquid-liquid extraction and subsequent gas chromatographic mass-spectrometric detection has been developed for determination of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in different hemp foods. After addition of Δ8-tetrahydrocannabinol as internal standard, both solid and liquid specimens were extracted with two volumes of 2 ml of hexane/isopropanol (9:1): Chromatography was performed on a fused silica capillary column and analytes were determined in the selected-ion-monitoring (SIM) mode. The method was validated in the range 1-50 ng/ml liquid samples or 1-50 ng/g solid samples for THC and CBN, and 2-50 ng/ml or ng/g for CBD. Mean recoveries ranged between 78.8 and 90.2% for the different analytes in solid and liquid samples. The quantification limits were 1 ng/ml or ng/g for THC and CBN and 2 ng/ml or ng/g CBD. The method was applied to analysis of various hemp foods. THC content in different products varied 50-fold, whereas CBN and CBD were absent in some samples and achieved hundreds of ng/ml or ng/g in others. The concentration ratio (THC + CBN)/CBD was used to differentiate between the phenotypes of cannabis plants in different specimens. Products possibly originating from drug-type cannabis plants were found in the majority of analyzed specimens.