title: Rapid analysis of cocaine and metabolites in urine using microextraction in packed sorbent and GC/MS.
abstract: Cocaine is still one of the most abused drugs worldwide and, as such, it is often screened for in driving-under-the-influence or workplace drug - testing scenarios. A large number of samples have usually to be processed in those situations, and this requires fast and simple extraction procedures for the detection and quantification of the drugs. The present work describes an ultrafast and fully validated procedure for the simultaneous detection and quantification of cocaine and its two main metabolites, ecgonine methyl ester and benzoylecgonine, in urine using microextraction by packed sorbent and GC-MS. A small sample volume (200 μL) was used, and a fast extraction procedure together with a microwave-assisted derivatization (800 W, 2 min) allowed the quantification of all analytes in a range of 25 to 1000 ng/mL (r2> 0.99). Inter-day precision revealed coefficients of variation (CVs) lower than 10% for all analytes at the tested concentration levels, with an accuracy within a ±7% interval, with the exception of EME's lowest calibrator (±17%). Intra-day CVs were lower than 15% at the studied concentration levels, with a mean relative error within a ±13% interval. Recoveries ranged from 14.5 to 37.2% (EME), 67.0 to 83.3% (cocaine), and 24.6 to 43.5% (BEG), allowing the limits of detection and quantification to be set at 25 ng/mL for all compounds. Graphical Abstract Schematized analysis of cocaine and metabolites in urine by MEPS- GC/MS.
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6201-556, Covilhã, Portugal.|Laboratório de Fármaco-toxicologia-Ubimedical, Universidade da Beira Interior, Estrada Municipal 506, 6200-284, Covilhã, Portugal.
authors.forename: Tiago
authors.initials: T
authors.lastname: Rosado
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6201-556, Covilhã, Portugal.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Gonçalves
authors.affiliation: Instituto Nacional de Medicina Legal e Ciências Forenses I.P.-Delegação do Centro, Largo da Sé Nova, 3000-213, Coimbra, Portugal.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Margalho
authors.affiliation: Instituto Nacional de Medicina Legal e Ciências Forenses I.P.-Delegação do Sul, Rua Manuel Bento de Sousa, 3, 1169-201, Lisbon, Portugal. mario.j.barroso@inmlcf.mj.pt.
authors.forename: Mário
authors.initials: M
authors.lastname: Barroso
authors.affiliation: CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6201-556, Covilhã, Portugal.|Laboratório de Fármaco-toxicologia-Ubimedical, Universidade da Beira Interior, Estrada Municipal 506, 6200-284, Covilhã, Portugal.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Gallardo
mesh_terms: D002138:Calibration; D003042:Cocaine / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans
chemical_list: D003042:Cocaine
keywords: Cocaine and metabolites; GC-MS; MEPS; Urine