Sorbent-Based Sampling With Two-Stage Trapping/Desorption Coupled to Comprehensive Two-Dimensional Gas Chromatography and Mass Spectrometry for Terpenoids Profiling in Cannabis

Abstract

Cannabis inflorescences represent an important source of many high-value bioactive specialized metabolites, among which the family of terpenes or terpenoids that are the largest classes of natural products known. Besides their biological activities either alone or synergistic with other terpenoids and/or cannabinoids, they are responsible for their distinctive flavour. In this study, we exploited the separation power and identification capabilities of comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) for the profiling of terpenes and terpenoids in cannabis inflorescences. The dynamic headspace (DHS) used herein for the extraction was chosen for its sensitivity, portability, suitability, as well as its versatility of sampling various natural products, including plant raw materials and different plant parts. The enrichment method and the following desorption into the GC were developed and optimized on both standards and real samples considering different sorbent traps (i.e. Tenax-TA, Carbotrap T420, Carbotrap 202), and evaluating key performance values. Analyte coverage, recovery and response reproducibility were used for the evaluation of the best performing thermal desorption tube. Considering terpenoids profiling on cannabis inflorescences, satisfactory extraction performance was observed with both Tenax-TA and Carbotrap T420. However, Tenax-TA provided a wider analyte coverage beyond the class of terpenoids, thus can be better suited for non-targeted analysis. On the other hand, peak width, peak height, peak quality and resolution were considered for the optimization of the chromatographic process, and more specifically the injection process, demonstrating the benefit of a secondary trapping/desorption stage with a cryotrap. Finally, considering the final DHSE-TD-GC×GC-MS conditions, terpenes and terpenoids were profiled in real-world cannabis inflorescences, highlighting the differences among the chemovars.