A simplified approach for isocratic HPLC analysis of cannabinoids by fine tuning chromatographic selectivity

The increasing interest in cannabinoids, both in hemp plant material and hemp-derived products, has sparked a renewed interest in cannabinoid analysis, mostly by liquid chromatography. A simple isocratic HPLC method for analysing cannabinoids in hemp (Cannabis sativa and Cannabis indica) plant material and its extracts has been developed. It was demonstrated that separation of chromatographically critical cannabinoids can be successfully done by a careful selection of a few parameters like common mobile phase modifiers and column temperature. Column temperature proved to be very critical, even under isocratic elution. Analyses are performed within 8.5 min. The use of 275 nm detection wavelength provided about an order of magnitude better sensitivity compared to the established 228 nm wavelength normally used in cannabinoid analysis. The method was validated for 11 major cannabinoids present in Cannabis samples and products, namely: cannabidivarine, cannabidiolic acid, cannabigerolic acid, cannabigerol, cannabidiol, tetrahydrocannabivarin, cannabinol, Δ9-tetrahydrocannabinol, Δ8-tetrahydrocannabinol, tetrahydrocannabinolic acid, and cannabichromene. The assessed limits of detection and the limits of quantitation range from 7 to 205 ng/mL and from 23 to 684 ng/mL, respectively. Being isocratic, with minimum adaptation, the method can be applied for screening work using a shorter column or for a better performing analysis by employing a longer column.