title: Determination of "new psychoactive substances" in postmortem matrices using microwave derivatization and gas chromatography-mass spectrometry.
abstract: Despite worldwide efforts aiming to ban the marketing and subsequent abuse of psychoactive substances such as synthetic cathinones and phenethylamines, there has been an alarming growth of both in recent years. Different compounds similar to those already existing are continuously appearing in the market in order to circumvent the legislation. An analytical methodology has been validated for qualitative and quantitative determinations of D-cathine (D-norpseudoehedrine), ephedrine, methcathinone, 1-(4-methoxyphenyl)-propan-2-amine (PMA), mephedrone, methedrone, 2,5-dimethoxy-4-methylamphetamine (DOM), 4-bromo-2,5-dimethoxyamphetamine (DOB), 2,5-dimethoxyphenethylamine (2C-H), 4-bromo-2,5-dimethoxyphenethylamine (2C-B), 4-iodo-2,5-dimethoxyphenethylamine (2C-I), 2-[2,5-dimethoxy-4-(ethylthio)phenyl]ethanamine (2C-T-2), 2,5-dimethoxy-4-isopropylthiophenethylamine (2C-T-4) and 2-[2,5-dimethoxy-4-(propylthio)phenyl]ethanamine (2C-T-7), in low volumes of vitreous humor (100 μL), pericardial fluid (250 μL) and whole blood (250 μL), using deutered amphetamine, ephedrine and mephedrone as internal standards. The validation parameters included selectivity, linearity and limits of detection and quantification, intra- and interday precision and trueness, recovery and stability. The method included mixed-mode solid phase extraction, followed by microwave fast derivatization and analysis by gas chromatography-mass spectrometry operated in selected ion monitoring mode. The procedure was linear between 5 and 600 ng/mL, with determination coefficients higher than 0.99 for all analytes. Intra- and interday precision ranged from 0.1 to 13.6%, while accuracy variability was within 80-120% interval from the nominal concentration at all studied levels. The extraction efficiencies ranged from 76.6 to 112.8%. Stability was considered acceptable for all compounds in the studied matrices. The developed assay was applied to authentic samples of the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.
authors.affiliation: Instituto Nacional de Medicina Legal e Ciências Forenses, I.P. (INMLCF, I.P.)-Delegação do Centro, Coimbra, Portugal. Electronic address: claudia.i.margalho@inmlcf.mj.pt.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Margalho
authors.affiliation: Instituto Nacional de Medicina Legal e Ciências Forenses, I.P. (INMLCF, I.P.)-Delegação do Centro, Coimbra, Portugal.
authors.forename: Alice
authors.initials: A
authors.lastname: Castanheira
authors.affiliation: Instituto Nacional de Medicina Legal e Ciências Forenses, I.P. (INMLCF, I.P.)-Delegação do Centro, Coimbra, Portugal; Faculdade de Medicina da Universidade de Coimbra, Portugal.
authors.forename: Francisco Corte
authors.initials: FC
authors.lastname: Real
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Portugal.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Gallardo
authors.affiliation: Servicio de Toxicología Forense, Instituto Universitario de Ciencias Forenses Universidad de Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: López-Rivadulla
mesh_terms: D000470:Alkaloids / Q000097:blood / Q000737:chemistry; D004355:Drug Stability; D053593:Forensic Toxicology; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D057230:Limit of Detection; D016014:Linear Models; D008872:Microwaves; D010627:Phenethylamines / Q000097:blood / Q000737:chemistry; D011619:Psychotropic Drugs / Q000097:blood* / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D000470:Alkaloids; D010627:Phenethylamines; D011619:Psychotropic Drugs; C023665:cathinone
keywords: Alternative biological matrices; Cathinones; Gas chromatography–mass spectrometry; Microwave fast derivatization; Phenethylamines