AOAC International has announced that a liquid chromatography–diode array detection (LC-DAD) method previously approved as Official Method of Analysis 2018.11 for cannabinoids in cannabis plant materials, concentrates, and oils, is now approved for hemp.
“Until now, no globally recognized method for validating the potency of hemp was available to laboratories,” said Scott Coates, program lead for AOAC’s Cannabis Analytical Science Program (CASP).
American Herbal Products Association (AHPA) Chief Science Officer Dr. Holly E. Johnson chairs the CASP working group, which includes members from industry, government, and academia, that created the Standard Method Performance Requirements (SMPR 2019.003) for evaluating candidate methods.
Method development was led by Dr. Katerina Mastovska from AHPA-member company Eurofins Food Integrity & Innovation (Madison, WI) in collaboration with University of Chemistry and Technology (Prague, Czech Republic).
The new validation and approval will allow laboratories to evaluate hemp for tetrahydrocannabinol (THC) on a dry-weight basis, as described by the U.S. Department of Agriculture’s Interim Final Rule governing the production of hemp under the 2018 Agriculture Improvement Act, known as the Farm Bill. A fundamental requirement of the program is testing for THC levels.
Official Method of Analysis 2018.11 is a liquid chromatography–diode array detection (LC-DAD) technique with optional mass spectrometric detection of Δ9-tetrahydrocannabinol (Δ9-THC) and tetrahydrocannabinolic acid (THCA) individually, so their concentrations can be reported either individually or as total THC. Official Method of Analysis 2018.11 is applicable to concentrates, oils and plant materials of Cannabis spp., including hemp.
With modification to include a procedure for sample dry weight determination, Official Method of Analysis 2018.11 was approved for hemp testing by an AOAC Expert Review Panel chaired by Melissa Phillips, research chemist at the U.S. National Institute of Standards and Technology (NIST), following a rigorous months-long review and validation process.
“The performance of this method has been demonstrated thoroughly, and laboratories in the hemp industry can confidently implement this straightforward method for determination of total THC on a dry-weight basis,” said Phillips.
The method was evaluated against requirements of Standard Method Performance Requirement (SMPR) Quantitation of Cannabinoids in Plant Materials of Hemp (Low THC Varieties of Cannabis sp.). This standard was developed by CASP in 2019 and is referenced in the U.S. Department of Agriculture Hemp Program’s Interim Final Rule guidance as the recommended standard for laboratories to meet when selecting a method for analyzing THC levels.
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