title: Simultaneous determination of fifteen low-dosed benzodiazepines in human urine by solid-phase extraction and gas chromatography-mass spectrometry.
abstract: A gas chromatographic-mass spectrometric method was developed for the simultaneous analysis of 15 low-dosed benzodiazepines, both parent compounds and their corresponding metabolites, in human urine. The target compounds are alprazolam, alpha-hydroxyalprazolam, 4-hydroxyalprazolam, flunitrazepam, 7-aminoflunitrazepam, desmethylflunitrazepam, flurazepam, hydroxyethylflurazepam, nitrogen-desalkylflurazepam, ketazolam, oxazepam, lormetazepam, lorazepam, triazolam and alpha-hydroxytriazolam. Nitrogen-methylclonazepam is used as the internal standard. The urine sample preparation involves enzymatic hydrolysis of the conjugated metabolites with Helix pomatia beta-glucuronidase for 1 h at 56 degrees C followed by solid-phase extraction on a phenyl-type column. The extracted benzodiazepines are subsequently analyzed on a polydimethylsiloxane column using on-column injection to enhance sensitivity. The extraction efficiency exceeded 80% for all compounds except for oxazepam, lorazepam and 4-hydroxyalprazolam which had recoveries of about 60%. The LODs ranged from 13 to 30 ng/ml in the scan mode and from 1.0 to 1.7 ng/ml in the selected ion monitoring (SIM) mode. Linear calibration curves were obtained in the concentration ranges from 50 to 1000 ng/ml in the scan mode and from 5 to 100 ng/ml in the SIM mode. The within-day and day-to-day relative standard deviations at three different concentrations never exceeded 15%.
authors.affiliation: Laboratorium voor Toxicologie, Universiteit Gent, Ghent, Belgium.
authors.forename: D
authors.initials: D
authors.lastname: Borrey
authors.forename: E
authors.initials: E
authors.lastname: Meyer
authors.forename: W
authors.initials: W
authors.lastname: Lambert
authors.forename: C
authors.initials: C
authors.lastname: Van Peteghem
authors.forename: A P
authors.initials: AP
authors.lastname: De Leenheer
mesh_terms: D001569:Benzodiazepines / Q000652:urine*; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001569:Benzodiazepines