title: Detection of Delta9-tetrahydrocannabinolic acid A in human urine and blood serum by LC-MS/MS.
abstract: Delta9-tetrahydrocannabinolic acid A (Delta9-THCA-A) is the precursor of Delta9-tetrahydrocannabinol (Delta9-THC) in hemp plants. During smoking, the non-psychoactive Delta9-THCA-A is converted to Delta9-THC, the main psychoactive component of marihuana and hashish. Although the decarboxylation of Delta9-THCA-A to Delta9-THC was assumed to be complete--which means that no Delta9-THCA-A should be detectable in urine and blood serum of cannabis consumers--we found Delta9-THCA-A in the urine and blood serum samples collected from police controls of drivers suspected for driving under the influence of drugs (DUID). For LC-MS/MS analysis, urine and blood serum samples were prepared by solid-phase extraction. Analysis was performed with a phenylhexyl column using gradient elution with acetonitrile. For detection of Delta9-THCA-A, the mass spectrometer (MS) (SCIEX API 365 triple-quadrupole MS with TurboIonSpray source) was operated in the multiple reaction monitoring (MRM) mode using the following transitions: m/z357 --> 313, m/z357 --> 245 and m/z357 --> 191. Delta9-THCA-A could be detected in the urine and blood serum samples of several cannabis consumers in concentrations of up to 10.8 ng/ml in urine and 14.8 ng/ml in serum. The concentration of Delta9-THCA-A was below the Delta9-THC concentration in most serum samples, resulting in molar ratios of Delta9-THCA-A/Delta9-THC of approximately 5.0-18.6%. Only in one case, where a short elapsed time between the last intake and blood sampling is assumed, the molar ratio was 18.6% in the serum. This indicates differences in elimination kinetics, which need to be investigated in detail.
authors.affiliation: Institute of Forensic Medicine, Forensic Toxicology, University Hospital Freiburg, Albertstrasse 9, D-79104 Freiburg, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Jung
authors.forename: Juergen
authors.initials: J
authors.lastname: Kempf
authors.forename: Hellmut
authors.initials: H
authors.lastname: Mahler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Weinmann
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D013759:Dronabinol / Q000097:blood* / Q000652:urine*; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*; D016482:Urinalysis / Q000379:methods*
chemical_list: D013759:Dronabinol