title: Simple method for determination of cocaine and main metabolites in urine by CE coupled to MS.
abstract: In this work, a simple method for the simultaneous determination of cocaine (COC) and five COC metabolites (benzoylecgonine, cocaethylene (CET), anhydroecgonine, anhydroecgonine methyl ester and ecgonine methyl ester) in human urine using CE coupled to MS via electrospray ionization (CE-ESI-MS) was developed and validated. Formic acid at 1 mol/L concentration was used as electrolyte whereas formic acid at 0.05 mol/L concentration in 1:1 methanol:water composed the coaxial sheath liquid at the ESI nozzle. The developed method presented good linearity in the dynamic range from 250 ng/mL to 5000 ng/mL (coefficient of determination greater than 0.98 for all compounds). LODs (signal-to-noise ratio of 3) were 100 ng/mL for COC and CET and 250 ng/mL for the other studied metabolites whereas LOQ's (signal-to-noise ratio of 10) were 250 ng/mL for COC and CET and 500 ng/mL for all other compounds. Intra-day precision and recovery tests estimated at three different concentration levels (500, 1500 and 5000 ng/mL) provided RSD lower than 10% (except anhydroecgonine, 18% RSD) and recoveries from 83-109% for all analytes. The method was successfully applied to real cases. For the positive urine samples, the presence of COC and its metabolites was further confirmed by MS/MS experiments.
authors: Institute of Chemistry, University of Sao Paulo, Sao Paulo, Brazil.
authors: José Luiz
authors: JL
authors: da Costa
authors: Fernando Gustavo
authors: FG
authors: Tonin
authors: Luiz Antonio
authors: LA
authors: Zanolli
authors: Alice Aparecida da Matta
authors: AA
authors: Chasin
authors: Marina Franco Maggi
authors: MF
authors: Tavares
mesh_terms: D003042:Cocaine / Q000031:analogs & derivatives* / Q000652:urine*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: C068464:anhydroecgonine methyl ester; C005618:benzoylecgonine; C066444:cocaethylene; D003042:Cocaine; C034524:ecgonine methyl ester