HPLC-UV-HRMS analysis of cannabigerovarin and cannabigerobutol, the two impurities of cannabigerol extracted from hemp

A sensitive and straightforward HPLC-UV method was developed for the simultaneous quantification of the two main impurities in "pure" commercial cannabigerol (CBG) samples. The identification of such impurities, namely cannabigerovarin (CBGV) and cannabigerobutol (CBGB), the propyl and butyl homologs of CBG, respectively, was accomplished employing the high-resolution mass spectrometry (HRMS) technique, and subsequently confirmed by comparison with the same compounds obtained by chemical synthesis. Complete spectroscopic characterization (NMR, FT-IR, UV, and HRMS) of both impurities is reported in the present work. The method was validated in terms of linearity, which was assessed in the range 0.01-1.00 μg/mL, sensitivity, selectivity, intra- and inter-day accuracy and precision, and short-term stability, which all satisfied the acceptance criteria of the ICH guidelines. Application of the method to the analysis of four commercial CBG samples highlighted a certain variability in the impurity profile that might be ascribed to the hemp variety of the starting plant material. With these new analytical standards in hand, it would be interesting to investigate their concentrations in different hemp varieties and expand the scope of a phytocannabinomics approach for a comprehensive profiling of this remarkable class of natural compounds.