Effects of ph and amount of acetonitrile on the separation of cannabinoids

Abstract

Objective: During reversed-phase high-performance liquid chromatography (HPLC) analyses, optimization of separation can be achieved by selecting appropriate chromatographic conditions. The retention time, peak shape, and peak size of chromatographic peaks are dependent on amount of organic modifier in the mobile phase and buffer pH. The aim of this study was to investigate the effects of varying pH, acetonitrile composition and flow rate of the mobile phase, and temperature of the stationary phase and wavelength in the development of a method to separate Δ9 tetrahydrocannabinol, cannabidiol, and cannabinol.

Methods: Mobile phases with different buffer pHs and acetonitrile composition were used with ultraviolet (UV) detection wavelength of 220 nm and 228 nm. The AUPs and retention times were observed using different mobile phase flow rates and stationary phase temperatures.

Results: The best results were obtained when using a mobile phase composition of 20% phosphate buffer pH 2.5 or pH 3 and 80% acetonitrile v/v at a flow rate of 2 mL/min at 220 nm.

Conclusion: This rapid and easy-to-use HPLC method describes the effect of changing important chromatographic parameters on separation and retention time of cannabinoids and can be effectively applied for high throughput analysis.