title: Hollow-fiber liquid-phase microextraction and gas chromatography-mass spectrometry of barbiturates in whole blood samples.
abstract: Here, we present a method for measuring barbiturates (butalbital, secobarbital, pentobarbital, and phenobarbital) in whole blood samples. To accomplish these measurements, analytes were extracted by means of hollow-fiber liquid-phase microextraction in the three-phase mode. Hollow-fiber pores were filled with decanol, and a solution of sodium hydroxide (pH 13) was introduced into the lumen of the fiber (acceptor phase). The fiber was submersed in the acidified blood sample, and the system was subjected to an ultrasonic bath. After a 5 min extraction, the acceptor phase was withdrawn from the fiber and dried under a nitrogen stream. The residue was reconstituted with ethyl acetate and trimethylanilinium hydroxide. An aliquot of 1.0 μL of this solution was injected into the gas chromatograph/mass spectrometer, with the derivatization reaction occurring in the hot injector port (flash methylation). The method proved to be simple and rapid, and only a small amount of organic solvent (decanol) was needed for extraction. The detection limit was 0.5 μg/mL for all the analyzed barbiturates. The calibration curves were linear over the specified range (1.0 to 10.0 μg/mL). This method was successfully applied to postmortem samples (heart blood and femoral blood) collected from three deceased persons previously exposed to barbiturates.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of São Paulo, Brazil. rafaelmenck@usp.br
authors.forename: Rafael Menck
authors.initials: RM
authors.lastname: de Almeida
authors.forename: Diógenes Saulo
authors.initials: DS
authors.lastname: de Lima
authors.forename: Saskia Carolina
authors.initials: SC
authors.lastname: Seulin
authors.forename: Vilma
authors.initials: V
authors.lastname: Leyton
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: D001463:Barbiturates / Q000097:blood* / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D059627:Liquid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D015394:Molecular Structure
chemical_list: D001463:Barbiturates