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Optimization of the quantitative analysis of the major cannabis metabolite (11‐nor‐9‐COOH‐Δ 9 ‐tetrahydrocannabinol) in urine by gas chromatography/mass spectrometry
Author(s) -
Congost M.,
de la Torre R.,
Segura J.
Publication year - 1988
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200160172
Subject(s) - chromatography , chemistry , urine , mass spectrometry , gas chromatography–mass spectrometry , gas chromatography , metabolite , trimethylsilyl , extraction (chemistry) , cannabis , tetrahydrocannabinol , cannabinol , quantitative analysis (chemistry) , cannabinoid , organic chemistry , medicine , biochemistry , receptor , psychiatry
A gas chromatographic/mass spectrometric electron impact method is presented for the detection and quantification of 11‐nor‐9‐carboxy‐Δ 9 ‐tetrahydrocannabinol (THC‐COOH) in urine, for use in the confirmation of presumptive results obtained by other techniques. Four extraction procedures, two solid‐liquid and two liquid‐liquid, have been compared. A comparison of two trimethylsilylating methods demonstrates that the best results are obtained by the use of a mixture containing N ‐methyl‐ N ‐trimethylsilyl‐trifluoroacetamide, trimethyliodosilane and dithioerithritol (100:0.2:1) v/v/w. The use of ketoprofen as a new internal standard for the quantification of THC‐COOH has proved to be very effective. Both spiked samples and samples from cannabis users have been successfully analysed. It has also been demonstrated that the presence of other drugs of abuse in urine samples do not interfere with cannabis quantification by the method reported here.