title: Determination of opiates in whole blood and vitreous humor: a study of the matrix effect and an experimental design to optimize conditions for the enzymatic hydrolysis of glucuronides.
abstract: Undoubtedly, whole blood and vitreous humor have been biological samples of great importance in forensic toxicology. The determination of opiates and their metabolites has been essential for better interpretation of toxicological findings. This report describes the application of experimental design and response surface methodology to optimize conditions for enzymatic hydrolysis of morphine-3-glucuronide and morphine-6-glucuronide. The analytes (free morphine, 6-acetylmorphine and codeine) were extracted from the samples using solid-phase extraction on mixed-mode cartridges, followed by derivatization to their trimethylsilyl derivatives. The extracts were analysed by gas chromatography-mass spectrometry with electron ionization and full scan mode. The method was validated for both specimens (whole blood and vitreous humor). A significant matrix effect was found by applying the F-test. Different recovery values were also found (82% on average for whole blood and 100% on average for vitreous humor). The calibration curves were linear for all analytes in the concentration range of 10-1,500 ng/mL. The limits of detection ranged from 2.0 to 5.0 ng/mL. The method was applied to a case in which a victim presented with a previous history of opiate use.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of São Paulo, Brazil.
authors.forename: Livia Rentas
authors.initials: LR
authors.lastname: Sanches
authors.forename: Saskia Carolina
authors.initials: SC
authors.lastname: Seulin
authors.forename: Vilma
authors.initials: V
authors.lastname: Leyton
authors.forename: Beatriz Aparecida Passos Bismara
authors.initials: BA
authors.lastname: Paranhos
authors.forename: Carlos Augusto
authors.initials: CA
authors.lastname: Pasqualucci
authors.forename: Daniel Romero
authors.initials: DR
authors.lastname: Muñoz
authors.forename: Michael David
authors.initials: MD
authors.lastname: Osselton
authors.forename: Mauricio
authors.initials: M
authors.lastname: Yonamine
mesh_terms: D002138:Calibration; D003061:Codeine / Q000032:analysis / Q000378:metabolism; D053593:Forensic Toxicology / Q000379:methods; D008401:Gas Chromatography-Mass Spectrometry; D005966:Glucuronidase / Q000378:metabolism; D020719:Glucuronides / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D009022:Morphine Derivatives / Q000032:analysis / Q000378:metabolism*; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization; D015813:Substance Abuse Detection / Q000379:methods*; D014822:Vitreous Body / Q000737:chemistry / Q000378:metabolism*
chemical_list: D020719:Glucuronides; D009022:Morphine Derivatives; C035349:morphine-6-glucuronide; D005966:Glucuronidase; C026979:6-O-monoacetylmorphine; C018108:morphine-3-glucuronide; D003061:Codeine