title: LC-MS-MS method for simultaneous determination of THCCOOH and THCCOOH-glucuronide in urine: Application to workplace confirmation tests.
abstract: Cannabis is the one of the most frequently detected drug in workplace drug testing and in cases of driving under influence of drugs, and there is a greater demand for sensitive, rapid and reliable methods for confirming the presence of this drug in biological samples. This paper describes an LC-MS-MS procedure for direct analysis of cTHC and cTHC-glucuronide in urine, without hydrolysis of the samples or derivatisation. The sample preparation is very simple and consist only in a dilution of urine with methanol 1:1 (v/v) after adding the deuterated internal standard (cTHC-d3); then 10μl of the final solution is injected in LC-MS-MS. Chromatographic separation was performed using a reversed-phase column and gradient elution with 0.01% formic acid/acetonitrile/methanol and two MS-MS transitions for each substance were monitored. The method was fully validated and proved to be accurate (RSD <15%), precise (intra-day CV <10%) and sensitive with a limit of detection (LOD) of 5ng/ml for both the compounds studied. Linearity was tested in the range 5-1000ng/ml and the values of R(2) resulted >0.99. The developed method was applied to several authentic samples of urine which tested positive in the immunoassay screening and 98% of them was confirmed.
authors.affiliation: Institute of Legal Medicine, Catholic University of the Sacred Heart, Largo Francesco Vito 1, Rome 00168, Italy. marialinda.felli@rm.unicatt.it
authors.forename: M
authors.initials: M
authors.lastname: Felli
authors.forename: S
authors.initials: S
authors.lastname: Martello
authors.forename: M
authors.initials: M
authors.lastname: Chiarotti
mesh_terms: D002853:Chromatography, Liquid; D013759:Dronabinol / Q000031:analogs & derivatives* / Q000652:urine*; D004651:Employment; D006801:Humans; D057230:Limit of Detection; D008385:Marijuana Smoking; D013058:Mass Spectrometry; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: C017747:tetrahydrocannabinol C4'-glucuronide; D013759:Dronabinol