Determination of Cannabinoids in Cannabis sativa Dried Flowers and Oils by LC-UV: Single-Laboratory Validation, First Action 2018.10.

Background: Legalization of Cannabis across many U.S. states and in Canada had led to an urgent need for validated analytical methods for the quantitation of cannabinoids in Cannabis sativa L. flowers and finished products. The AOAC Stakeholder Panel on Strategic Food Analytical Methods Cannabis Expert Review Panel (ERP) approved an HPLC-diode-array detection (DAD) method for First Action Official Methods^SM status.

Objective: To present Official Methods of Analysis^SM (OMA) 2018.10 method details, validation results, and additional method extension data as approved by the ERP and further requirements for Final Action Official Methods^SM status.

Methods: This previously published method used 80% aqueous methanol via sonication for extracting eight cannabinoids-tetrahydrocannabidiolic acid, tetrahydrocannabinol, cannabidiolic acid, cannabidiol, tetrahydrocannabivarin, cannabigerol, cannabinol, and cannabichromene-in dried flowers followed by reversed-phase chromatographic separation and UV detection.

Results: The original method underwent extensive method optimization and a single-laboratory validation. Additional requirements requested by the Standard Method Performance Requirement (SMPR^®) included a method extension, which was performed to collect repeatability data on two additional cannabinoids: cannabidivarinic acid and cannabigerolic acid. The methods performance was compared with the AOAC SMPR 2017.002 and 2017.001. RSD_r ranged from 0.78 to 10.08% and recoveries from 90.7 to 99.2% in several different chemotypes.

Conclusions: The ERP adopted the method and provided recommendations for achieving Final Action status.

Highlights: After submission of additional validation data, an HPLC-DAD method for quantitation of cannabinoids in dried flowers and oils was accepted for First Action Official Method status (OMA 2018.10).