Differentiation of marijuana headspace volatiles from other plants and hemp products using capillary microextraction of volatiles (CMV) coupled to gas-chromatography–mass spectrometry (GC–MS)

Abstract

The ability to rapidly detect illicit drugs, such as marijuana, is critical to policing legislation across the country. However, it is often difficult to distinguish or identify small quantities of drugs in large spaces without the aid of trained canines. A new device, the capillary microextractor of volatiles (CMV), has the potential to provide rapid detection due to its ability to collect and preconcentrate volatile organic compounds (VOCs) directly from air within minutes. Analysis of the captured compounds can then be performed using a gas chromatography–mass spectrometer (GC–MS). This study focuses on the detection of marijuana volatiles using the CMV as a sampling and preconcentration device given the hypothesis that marijuana will have a distinct chemical profile, or collection of VOCs, that distinguishes it from related plants and other products that could emit similar compounds. Volatile compounds from the headspace of marijuana, related plants, and hemp products were extracted using the CMV and analyzed with GC–MS. The compounds identified and the chemical profiles of each sample were then compared to the volatiles found in the headspace of authentic marijuana samples. The findings presented here suggest that marijuana plants emit volatiles that are readily distinguished from the other samples tested in this study. The distinguishing compounds included α-santalene, valencene, and β-bisabolene. In some cases, THC and cannabinol were also present in the headspace of marijuana. Although these findings support the hypothesis that marijuana has a distinct chemical VOC signature, further work to create a larger database of potential plants and materials is recommended prior to routine use of the CMV coupled to a GC–MS in forensic casework.