Confirmatory method for detection 11-nor-Ã¯ÂÂ9-tetrahydrocannabinol-9- carboxylic acid in urine samples using gas chromatography mass spectrometry (GC/MS)Author(s): Rabie S.Farag, Sayed R.Abed Al-Salam
Gas chromatography mass spectrometry (GC/MS) analysis of 11-Nor-ï9- tetrahydrocannabinol-9-carboxylic acid (THC-COOH), themajormetabolite of tetrahydrocannabinol in biological samples is reported, the THCmetabolite obtained by alkaline hydrolysis fromurine sampleswere extracted using mixture of solvents followed by trimethylsilylation. The dervatized extract was submitted to GC/MS analysis of EI-SIM mode. Different factors were studied as pH, temperature, time to establish the best conditions for the determination. The calibration curves of THC-COOH derivatized (THCCOOH- TMS) in urine samples were linear in the concentration range from 10 to 150ïg/ml. the proposed method is able to detect the major metabolite of cannabis derivatives at very low level (10ïg/ml) with high specificity so these analytical procedure can be used as confirmatory method in drug testing of cannabis use.