title: Determination of cocaine and its metabolites in plasma by porous membrane-protected molecularly imprinted polymer micro-solid-phase extraction and liquid chromatography-tandem mass spectrometry.
abstract: A selective molecularly imprinted polymer synthesized for the selective retention of cocaine (COC) and its metabolites [benzoylecgonine (BZE), ecgonine methyl ester (EME), and cocaethylene (CE)] was used as a solid adsorbent for assessing cocaine abuse by plasma analysis. The MIP beads (50mg) were loaded inside a cone shaped device made of a polypropylene (PP) membrane for micro-solid-phase extraction (μ-SPE). High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was used for quantifying the analytes after MIP-μ-SPE. The best retention capabilities were reached when loading plasma samples (within the 0.1-5.0mL range), previously adjusted to pH 5.5 by orbital-horizontal shaking (150rpm, 50°C) for 10min. Analyte elution was achieved by subjecting the MIP-μ-SPE device to ultrasound (37kHz, 325W) with 10mL of dichloromethane/2-propanol/ammonium hydroxide (76:20:4) for 8min. After eluate evaporation to dryness and re-dissolution in 100μL of mobile phase, the MIP-μ-SPE method yielded a pre-concentration factor of 50. Precision was assessed by intra-day and inter-day assays, and accuracy (intraday and inter-day analytical recovery, as well as the analysis of a BTMF 1/11-B control serum sample) show that the developed method is highly precise and accurate. In addition, the limits of detection, ranging from 0.061ngmL(-1) for COC to 0.87ngmL(-1) for BZE, were low enough for confirmative conclusions regarding cocaine abuse. The method was used for screening/quantifying cocaine and metabolites in plasma samples from poly-drug abusers.
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Sánchez-González
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: García-Carballal
authors.affiliation: Department of Pathologic Anatomy and Forensic Sciences, Faculty of Medicine, University of Santiago de Compostela, Rúa de San Francisco, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: Pamela
authors.initials: P
authors.lastname: Cabarcos
authors.affiliation: Department of Pathologic Anatomy and Forensic Sciences, Faculty of Medicine, University of Santiago de Compostela, Rúa de San Francisco, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Tabernero
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Bermejo-Barrera
authors.affiliation: Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela, Spain. Electronic address: antonio.moreda@usc.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Moreda-Piñeiro
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000031:analogs & derivatives / Q000097:blood* / Q000378:metabolism*; D055030:Drug Users; D006801:Humans; D054802:Molecular Imprinting; D011108:Polymers / Q000737:chemistry; D016062:Porosity; D052616:Solid Phase Extraction / Q000379:methods*; D053719:Tandem Mass Spectrometry; D013997:Time Factors
chemical_list: D011108:Polymers; C005618:benzoylecgonine; C066444:cocaethylene; D003042:Cocaine; C034524:ecgonine methyl ester
keywords: Cocaine; High performance liquid chromatography tandem mass spectrometry; Microsolid-phase extraction; Molecularly imprinted polymer; Plasma; Porous membrane-protected