Gas chromatography of cannabis constituents, including cannabinoid acids, with on-column alkylation and esterification

✍ Scribed by Sven Björkman

• Book ID: 104145105
• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 627 KB
• Volume: 237
• Category: Article
• ISSN: 1873-3778
• DOI: 10.1016/s0021-9673(00)97625-8

✦ Synopsis

Neutral cannabis constituents and cannabinoid acids were gas chromatographed with on-column methylation of phenolic hydroxyl groups and esterification of carboxylic acid functions. Injection of cannabis extracts as solutions in 2 44 dimethylformamide dimethylacetal in pyridine gave quantitative or near-quantitative conversion of cannabinol and tetrahydrocannabinol into methyl ethers, while cannabidiol gave a monomethyl and a dimethyl derivative, Also cannabidiolic acid, tetrahydrocannabinolic acid and the tetrahydrocannabinol 7-acid metabolite chromatographed well as methyl esters and ethers. The mass spectra of the methyl derivatives eve more pertinent structural information than those of the corresponding TIMS derivatives. This simple derivatization procedure should conceivably prove useful for the analysis of other heat-labile biological samples. Indeed, the CI spectra of compounds VII, X, XI and V consisted of an intense [M + H]' ion peak and no fragment peaks of more than 5 "/, abundaace. * The two phenolic functions of cannabidiol are eqtivaIent_ -Contaminant from plasticizers. S The two pheno!ic functions ofcannabidiolic acid are not equivaIen& and the peak is probably due to a mi..ture of the two isomers. _ A B Fis 3. The structures of the cannabis constituents and the2 derivatives. The folkwing compounds are represent& by formula A: I.