title: Solid phase microextraction and gas chromatography-mass spectrometry methods for residual solvent assessment in seized cocaine and heroin.
abstract: A simple sample pre-treatment method based on solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) has been optimized and validated for the assessment of 15 residual solvents (2-propanol, 2-methylpentane, 3-methylpentane, acetone, ethyl acetate, benzene, hexane, methylcyclohexane, methylcyclopentane, m-xylene, propyl acetate, toluene, 1,2,4-trimethylbenzene, dichloromethane, and ethylbenzene) in seized illicit cocaine and heroin. DMSO and DMF as sample diluents were found to offer the best residual solvent transference to the head space for further adsorption onto the SPME fiber, and the developed method therefore showed high sensitivity and analytical recovery. Variables affecting SPME were fully evaluated by applying an experimental design approach. Best conditions were found when using an equilibration time of 5 min at 70 °C and headspace sampling of residual solvents at the same temperature for 15 min. Method validation, performed within the requirements of international guidelines, showed excellent sensitivity, as well as intra- and inter-day precision and accuracy. The proposed methodology was applied to 96 cocaine samples and 14 heroin samples seized in Galicia (northwestern Spain) within 2013 and 2014.
authors.affiliation: Institute of Forensic Sciences, Faculty of Medicine, Universidade de Santiago de Compostela, Rúa San Francisco, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: Pamela
authors.initials: P
authors.lastname: Cabarcos
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Universidade de Santiago de Compostela, Avenida das Ciencias, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Herbello-Hermelo
authors.affiliation: Institute of Forensic Sciences, Faculty of Medicine, Universidade de Santiago de Compostela, Rúa San Francisco, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Álvarez-Freire
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Universidade de Santiago de Compostela, Avenida das Ciencias, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Moreda-Piñeiro
authors.affiliation: Institute of Forensic Sciences, Faculty of Medicine, Universidade de Santiago de Compostela, Rúa San Francisco, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Tabernero
authors.affiliation: Institute of Forensic Sciences, Faculty of Medicine, Universidade de Santiago de Compostela, Rúa San Francisco, s/n, 15782, Santiago de Compostela, Spain. anamaria.bermejo@usc.es.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Bermejo
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Universidade de Santiago de Compostela, Avenida das Ciencias, s/n, 15782, Santiago de Compostela, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Bermejo-Barrera
mesh_terms: D000779:Anesthetics, Local / Q000032:analysis*; D003042:Cocaine / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D003932:Heroin / Q000032:analysis*; D013287:Illicit Drugs / Q000032:analysis*; D057230:Limit of Detection; D009294:Narcotics / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods*; D012997:Solvents / Q000032:analysis; D015813:Substance Abuse Detection / Q000379:methods
chemical_list: D000779:Anesthetics, Local; D013287:Illicit Drugs; D009294:Narcotics; D012997:Solvents; D003932:Heroin; D003042:Cocaine
keywords: GC-MS; Residual solvents; SPME; Seized cocaine; Seized heroin