Gas chromatography/electron ionization mass spectrometry (GC/EI-MS) for the characterization of phytocannabinoids in Cannabis sativa

Abstract Cannabis sativa 's biological effects are due to the phytocannabinoid family of compounds. There are almost 200 cannabinoids known now, not only from Cannabis but also in several other plant species. The majority of interest resides in the two dominant phytocannabinoids present in different Cannabis varieties: delta-9-trans-tetrahydrocannabidiol (d9-trans-THC) responsible for the psychoactivity and cannabidiol (CBD) which has a number of medical uses. Both of these are decarboxylated neutral forms of their acid parent compounds which are the naturally-occurring forms of the phytocannabinoids. However, a number of studies show that the whole plant extracts often exert more biological effects than the isolated compounds. Thus, analytical efforts to better understand the complexity of the phytocannabinoids are warranted. Gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) has been used for characterization of the phytocannabinoids since its inception in the 1960s. It is still one of the most-used analytical techniques for determination of phytocannabinoids. GC/EI-MS analyses of underivatized extracts of a THC-type and a CBD-type cannabis are presented in detail, including mass spectra and chromatograms. The advantages and disadvantages of GC/EI-MS for characterization of phytocannabinoids are discussed. GC/EI-MS is shown to be a powerful analytical method for characterizing the complexity of the phytocannabinoids.