title: Determination of lorazepam in plasma and urine as trimethylsilyl derivative using gas chromatography-tandem mass spectrometry.
abstract: A procedure based on gas chromatography-tandem mass spectrometry for identification and quantitation of lorazepam in plasma and urine is presented. The analyte was extracted from biological fluids under alkaline conditions using solid-phase extraction with an Extrelut-1 column in the presence of oxazepam-d5 as the internal standard. Both compounds were then converted to their trimethylsilyl derivatives and the reaction products were identified and quantitated by gas chromatography-tandem mass spectrometry using the product ions of the two compounds (m/z 341, 306 and 267 for lorazepam derivative and m/z 346, 309 and 271 for oxazepam-d5 derivative) formed from the parent ions by collision-induced dissociation in the ion trap spectrometer. Limit of quantitation was 0.1 ng/ml. This method was validated for urine and plasma samples of individuals in treatment with the drug.
authors.affiliation: Clinical Biochemistry Department, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Pichini
authors.forename: R
authors.initials: R
authors.lastname: Pacifici
authors.forename: I
authors.initials: I
authors.lastname: Altieri
authors.forename: A
authors.initials: A
authors.lastname: Palmeri
authors.forename: M
authors.initials: M
authors.lastname: Pellegrini
authors.forename: P
authors.initials: P
authors.lastname: Zuccaro
mesh_terms: D014151:Anti-Anxiety Agents / Q000032:analysis* / Q000097:blood / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D008140:Lorazepam / Q000032:analysis* / Q000097:blood / Q000652:urine; D010076:Oxazepam / Q000737:chemistry; D012015:Reference Standards
chemical_list: D014151:Anti-Anxiety Agents; D010076:Oxazepam; D008140:Lorazepam