Chromatographic characterisation of 11 phytocannabinoids: Quantitative and fit-to-purpose performance as a function of extra-column variance.

Introduction: Cannabis sativa L. (cannabis) is utilised as a therapeutic and recreational drug. With the legalisation of cannabis in many countries and the anticipated regulation of potency that will accompany legalisation, analytical testing facilities will require a broadly applicable, quantitative, high throughput method to meet increased demand. Current analytical methods for the biologically active components of cannabis (phytocannabinoids) suffer from low throughput and/or an incomplete complement of relevant phytocannabinoids.

Objective: To develop a rapid, quantitative and broadly applicable liquid chromatography-tandem mass spectrometry analytical method for 11 phytocannabinoids in cannabis with acidic and neutral character.

Methodology: Bulk diffusion coefficients were calculated using the Taylor-Aris open tubular method, with four reference compounds used to validate the experimental set-up. Three columns were quantitatively evaluated using van Deemter plots and fit-to-purpose performance metrics. Low (1.2 μL ) and standard (3.6 μL ) extra-column variance ultra-high pressure liquid chromatography (UPLC) configurations were contrasted. Method performance was demonstrated with methanolic cannabis flower extracts.

Results: Bulk diffusion coefficients and van Deemter plots for 11 phytocannabinoids are reported. The developed chromatographic method includes the challenging Δ /Δ -tetrahydrocannabinol isobars and, at 6.5 min, is faster than existing methods targeting similar panels of biologically active phytocannabinoids.

Conclusions: The bulk diffusion coefficients and van Deemter curves informed the development of a rapid quantitative method and will facilitate potential expansion to include additional compounds, including synthetic cannabinoids. The developed method can be implemented with low or standard extra-column variance UPLC configurations.