Enhanced selectivity in the determination of delta9-tetrahydrocannabinol and two major metabolites in serum using ion-trap GC-MS-MS.
Cannabinoids were extracted from serum with C18 SPE cartridges and analyzed as their trimethylsilyl (TMS) derivatives. A benchtop gas chromatography-tandem mass spectrometry (GC-MS-MS) system based on an ion trap with external ionization was used. Quantitation was done in relation to trideuterated internal standards in dual MS-MS mode. Confirmation of the identity for the three compounds of interest, delta9-tetrahydrocannabinol (THC), 11-hydroxy-delta9-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-delta9-tetrahydrocannabinol (THCCOOH), was achieved by registering the daughter spectra in full scan mode. It was possible to identify the three compounds at concentrations down to 0.25 microg/L for THC, 0.5 microg/L for 11-OH-THC, and < 2.5 microg/L for THCCOOH by comparison with reference spectra. The limits of quantitation are better than 2 microg/L for THC, 5 microg/L for 11-OH-THC, and 8 microg/L for THCCOOH. The within-run and day-to-day precision for the three analytes were very similar and ranged from 4.2 to 10.4%.
Institute of Legal Medicine, Medical High-School Hannover, Germany.
J P
JP
Weller
M
M
Wolf
S
S
Szidat
D013759:Dronabinol / Q000031:analogs & derivatives* / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006213:Hallucinogens / Q000097:blood*; D006801:Humans; D012016:Reference Values; D012680:Sensitivity and Specificity
D006213:Hallucinogens; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol