HPLC–DAD determination of opioids, cocaine and their metabolites in plasma

Fernández, P.; Morales, L.; Vázquez, C.; Bermejo, A.M.; Tabernero, M.J.

doi:10.1016/j.forsciint.2005.10.016

« Previous Next »Forensic Science International
Volume 161, Issue 1 , Pages 31-35, 10 August 2006

HPLC–DAD determination of opioids, cocaine and their metabolites in plasma

Institute of Legal Medicine, Forensic Toxicology Service, Faculty of Medicine, University of Santiago de Compostela, C/San Francisco s/n, 15782 Santiago de Compostela, Spain

Received 21 April 2005; received in revised form 20 October 2005; accepted 20 October 2005. published online 21 November 2005.

Abstract

High performance liquid chromatography with diode array detection (HPLC–DAD) was used to develop a method for the simultaneous determination of morphine, codeine, 6-acetylmorphine (6AM), cocaine, benzoylecgonine (BEG), cocaethylene, methadone and its metabolite, 2-ethylidene-1,5-dimethyldiphenylpyrrolidine (EDDP), in plasma. Following solid-phase extraction with Bond Elut Certify cartridges, chromatography was performed on an X-Terra^® RP8 column (250mm×4.6mm i.d., 5μm particle size), using acetonitrile–phosphate buffer pH 6.53 as mobile phase and elution in the gradient mode. The detector response was linear at concentrations over the range 0.1–10μg/mL in plasma, and the correlation coefficients for the eight drugs studied were all higher than 0.99. The average extraction recoveries from plasma ranged from 60% for BEG to 95% for methadone. The precision was acceptable, with coefficients of variation oscillating between 2.55% and 6.45%. The accuracy was found to be within satisfactory limits (±8.1%). Finally, the method was applied to 21 plasma samples from fatal overdoses, obtaining positive results for two or more drugs.