Analytical procedure for the determination of the marijuana metabolite 11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid in oral fluid specimens.
The determination of the marijuana metabolite 11-nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THCA) in oral fluid specimens is described for the first time using a Quantisal oral fluid collection device and gas chromatography with single-quadrupole mass spectrometric detection. Oral fluid specimens were confirmed for the presence of THCA using two-dimensional gas chromatography-mass spectrometry in order to achieve the low concentration levels previously reported to be present in oral fluid. The extraction efficiency for THCA from the oral fluid collection pad was determined to be 80% at a concentration of 10 pg/mL with a coefficient of variation of 8.23%. The intraday precision of the assay ranged from 3.4% to 7.9% over four concentrations; the interday precision ranged from 8.3% to 18.5%. The limit of quantitation was 2 pg/mL. The method was applied to oral fluid specimens collected from a frequent user of marijuana. Samples were collected almost immediately after the subject smoked and then at intervals of 15 and 45 min and 1, 2, and 8 h after smoking. THCA was present in all the specimens, even the initial specimen taken almost immediately after smoking. The presence of THCA minimizes the argument for passive exposure to marijuana in drug-testing cases.
Moore
Christine
C
Immunalysis Corporation, 829 Towne Center Drive, Pomona, California 91767, USA. cmoore@immunalysis.com
Coulter
Cynthia
C
Rana
Sumandeep
S
Vincent
Michael
M
Soares
James
J
D013759:Dronabinol / Q000031:analogs & derivatives* / Q000032:analysis / Q000493:pharmacokinetics; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000378:metabolism*; D008875:Middle Aged; D009055:Mouth / Q000378:metabolism*; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D015813:Substance Abuse Detection
C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol