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 μL²) and standard (3.6 μL²) 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 Δ⁸/Δ⁹‐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.