Development and Optimization of an HPLC-PDA Method for the Determination of Major Cannabinoids in Hemp (Cannabis sativa L.) Essential Oil Obtained by Hydrodistillation

Abstract

The use of hemp (Cannabis sativa L.) essential oil (EO) has shown a significant increase in interest and use during recent years. In this work, a new and simple reversed-phase HPLC with photodiode-array (PDA) detector method has been developed and optimized for the detection and quantification of cannabidiolic acid (CBDA), cannabidiol (CBD), cannabinol (CBN), Δ9-tetrahydrocannabinol (Δ9-THC), and Δ9-tetrahydrocannabinolic acid (THCA). The cannabinoids were extracted from the EO by partition with n-hexane and water, followed by sonication, evaporation to dryness under nitrogen, and reconstitution with methanol:chloroform (9:1, v/v) before HPLC-PDA analysis. The method shows good selectivity and robustness, linearity in the range 0.5–100 mg L−1 with R2 higher than 0.999 for all cannabinoids analyzed, LOD of 0.11–0.16 mg L−1, and LOQ of 0.35–0.48 mg L−1. The recovery was between 78 and 100% and the intra-day and intermediate precision, expressed as relative standard deviation (RSD), was < 4% and 4–10%, respectively.