title: The determination of cocaine, benzoylecgonine, and cocaethylene in small-volume oral fluid samples by liquid chromatography-quadrupole-time-of-flight mass spectrometry.
abstract: A quantitative analysis was developed for the determination of cocaine, benzoylecgonine, and cocaethylene in oral fluid using liquid chromatography-tandem mass spectrometry. After internal standardization and solid-phase extraction, chromatographic separation was achieved on a reversed-phase column by gradient elution. The reconstructed mass chromatograms of the collision-induced dissociation transitions of m/z 290 --> m/z 168 (benzoylecgonine), m/z 304 --> m/z 168+119 (2'-methylbenzoylecgonine), m/z 304 --> m/z 182 (cocaine), m/z 318 --> m/z 196 (cocaethylene), and m/z 318 --> m/z 182+119 (2'-methylcocaine) were used for quantitation. The developed method was adequately validated. Good linearity was obtained from 10 to 1000 microg/L. Extraction recoveries exceeded 85% for all compounds. Excellent total and within-run reproducibilities (CV% < 20%) and accuracy figures were obtained. The limit of detection (signal-to-noise ratio >/= 3) was 1 microg/L for all three compounds. As such, a method for drug abuse confirmation analysis in oral fluid, compatible with the present day saliva collecting devices, is obtained. The method was applied to real samples (n = 15) obtained from suspected drug users, of which seven proved positive. The concentrations found in the positive samples were between 10.2 and 200.6 microg/L for cocaine, < limit of quantification (LOQ) and 10.5 microg/L for cocaethylene, and < LOQ and 59.2 microg/L for benzoylecgonine.
authors.affiliation: Laboratory of Medical Biochemistry and Clinical Analysis, Ghent University, Harelbekestraat 72, 9000 Ghent, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Clauwaert
authors.forename: T
authors.initials: T
authors.lastname: Decaestecker
authors.forename: K
authors.initials: K
authors.lastname: Mortier
authors.forename: W
authors.initials: W
authors.lastname: Lambert
authors.forename: D
authors.initials: D
authors.lastname: Deforce
authors.forename: C
authors.initials: C
authors.lastname: Van Peteghem
authors.forename: J
authors.initials: J
authors.lastname: Van Bocxlaer
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D003042:Cocaine / Q000031:analogs & derivatives* / Q000032:analysis*; D019970:Cocaine-Related Disorders / Q000175:diagnosis / Q000378:metabolism; D006801:Humans; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: C005618:benzoylecgonine; C066444:cocaethylene; D003042:Cocaine