Cannabinoid quantification is the most common analytical method performed by cannabis producers and testing facilities. Producers are required to define the quantity of cannabinoids in cannabis based products before release to the market. While there are regional variations in potency testing requirements and more than 60 cannabinoids present in cannabis, producers are typically required to define the quantity of the abundant psychoactive and non-psychoactive cannabinoids, Tetrahydrocannabinol (THC), Tetrahydrocannabinolic Acid (THCA), Cannabidiol (CBD), Cannabidiolic Acid (CBDA), Cannabigerol (CBG), and Cannabinol (CBN) (Figure 1). [1-2] Potency is typically expressed as the sum of acidic (CBDA and THCA) and neutral forms (CBD and THC) of cannabinoids. This is due to the fact that neutral cannabinoids do not occur in significant concentrations in plants as the plant primarily synthesizes the carboxylic acid forms, including Δ9 -tetrahydrocannabinolic acid A (THCA-A) and cannabidiolic acid (CBDA). Since the carboxylic acid forms are thermally unstable, they convert to their neutral forms when exposed to substantial heat, in excess of 90 °C, which can occur via smoking or in the production of food-based cannabinoid products (Figure 1) [3-4].
Maintaining the ratio of neutral/acid cannabinoid forms is critical in the sample preparation process as the goal is the accurately quantify the amount of both forms in the cannabis product. Sample disaggregation is the first step in a potency analysis and can be performed via manual hand grinding, rotor-stator homogenization, bead milling or cryo-milling. Herein we evaluate the effect of bead milling on sample temperature and acidic cannabinoid decarboxylation.
Figure 4A: Unprocessed cannabinoid 250 ppm standard showing elution of CBDA (9.039 min), CBD (9.979 min), THC (12.988 min), and THCA (14.264 min), cannabinoid standard