Development and validation of a method for the quantitation of Delta9tetrahydrocannabinol in oral fluid by liquid chromatography electrospray-mass-spectrometry.
Analysis of Delta(9)tetrahydrocannabinol (Delta(9)THC) and its metabolites in biological samples is of great relevance for forensic purposes. In the case of oral fluid (OF), the analysis should determine Delta(9)THC, whereas in urine, it detects the inactive metabolite tetrahydrocannabinol carboxylic acid (THC-COOH). Most laboratories analyze Delta(9)THC in such samples using GC-MS methods, but these procedures are time-consuming and involve unavoidable previous extraction and derivatization. No data is yet available on the application of liquid chromatography-mass-spectrometry to detect Delta(9)THC in oral fluid. We report a validation method in which the Delta(9)THC is isolated from oral fluid by a simple liquid-liquid extraction with hexane and subsequently analyzed by liquid chromatography-mass-spectrometry. The method here reported for the determination of Delta(9)THC in oral fluid only requires 200 microl of sample and achieves limits of detection of 2 ng/ml, and has been used to analyze oral fluid samples collected from current drug users.
Concheiro
M
M
Forensic Toxicology Service, Institute of Legal Medicine, Faculty of Medicine, Universidad de Santiago de Compostela, S. Francisco s/n, 15786 Santiago De Compostela, Spain.
de Castro
A
A
Quintela
O
O
Cruz
A
A
López-Rivadulla
M
M
D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D013759:Dronabinol / Q000032:analysis*; D006213:Hallucinogens / Q000032:analysis*; D006586:Hexanes; D006801:Humans; D007202:Indicators and Reagents; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D012997:Solvents; D021241:Spectrometry, Mass, Electrospray Ionization; D015813:Substance Abuse Detection / Q000379:methods
D006213:Hallucinogens; D006586:Hexanes; D007202:Indicators and Reagents; D012997:Solvents; D013759:Dronabinol