title: Use of solid-phase microextraction (SPME) for the determination of methadone and its main metabolite, EDDP, in plasma by gas chromatography-mass spectrometry.
abstract: A simple, rapid method for the determination of methadone and its metabolite 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) in plasma using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry is proposed. A 100-microm polydimethylsiloxane film fiber was exposed by immersion for 30 min in a diluted plasma solution (1:4 with buffer pH 9) containing both compounds and an internal standard (proadifen). Calibration curves were linear over the concentration range 50-2000 ng/mL. The analysis time was 45 min per sample. The determination of methadone and EDDP was subject to no interference. The performance of SPME was compared with that of liquid-liquid extraction, obtaining lower limits of detection for EDDP. The method using the two extraction procedures was applied to 10 plasma samples from methadone-treated patients.
authors.affiliation: Department of Legal Medicine, Faculty of Medicine, Santiago de Compostela, Spain.
authors.forename: A M
authors.initials: AM
authors.lastname: Bermejo
authors.forename: R
authors.initials: R
authors.lastname: Seara
authors.forename: A C
authors.initials: AC
authors.lastname: dos Santos Lucas
authors.forename: M J
authors.initials: MJ
authors.lastname: Tabernero
authors.forename: P
authors.initials: P
authors.lastname: Fernández
authors.forename: R
authors.initials: R
authors.lastname: Marsili
mesh_terms: D002138:Calibration; D003429:Cross Reactions; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008691:Methadone / Q000097:blood* / Q000302:isolation & purification; D008832:Microchemistry / Q000379:methods; D011335:Proadifen / Q000032:analysis; D011759:Pyrrolidines / Q000097:blood* / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D012828:Silicones / Q000737:chemistry; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; D011759:Pyrrolidines; D012828:Silicones; C013830:baysilon; D011335:Proadifen; D008691:Methadone; C010724:2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine