5.1 Gas chromatography and flame ionization detection provides a rapid means to identify and quantify cannabinoids in a variety of samples of interest. This test method allows producers of cannabis products to improve and optimize the quality of their products. For example, hemp extractors can use it to determine the efficiency of extraction processes and to verify that products meet regulatory requirements, ensuring safety and quality of products.

5.2 Cannabinoids, such as CBD and THC can be monitored throughout the production process. The determination of ?⁹-THC is often required for regulatory purposes and the determination of other THC isomers is often of interest. The United Nations Office on Drugs and Crime provides experimental details and guidance for use of GC to analyze cannabis related samples, including conditions suitable for decarboxylation of cannabinoid acids.3

5.3 Post-decarboxylated methodology is used. In decarboxylation, heat is used to liberate carbon dioxide from carboxylic acid cannabinoids, forming their corresponding neutral cannabinoids, for example, THC from THCA. It should be recognized that the hot temperature of the GC injection port itself is capable of effecting at least some decarboxylation (250?°C - Table 2), and many sample types, such as distillates, require no decarboxylation because it would have occurred during material processing. Therefore, some knowledge of sample properties and material processing is useful. Resulting determinations are for the total cannabinoid content of specific isomers, for example, total ?⁹-THC. For those samples requiring decarboxylation, the method is validated per Practice D8282 through the use of reference materials, spike and recovery of knowns, or through comparison with LC results. For example, carrying out the decarboxylation procedure of a standard containing known amounts of CBDA and CBN should yield the correct amounts of CBD and CBN, where CBN is not significantly changed and the mass of CBD formed from CBDA should be 0.877 × CBDA. The same ratio applies to THC and THCA. For other cannabinoids of interest, the conversion factor is derived from the ratio of formula masses of the neutral to that of its acid. If the observed conversion deviates significantly from expected results, then corrective action is necessary.

5.4 As an aid, users are referred to other methods for determination of individual cannabinoids and their acids, for example, Test Method D8375.

Note 1: Other ASTM standards are in development.