title: Sensitive and selective cocaine electrochemical detection using disposable sensors.
abstract: This paper describes the voltammetric determination of cocaine in presence of three different interferences that could be found in street samples using disposable sensors. The electrochemical analysis of this alkaloid can be affected by the presence of codeine, paracetamol or caffeine, whose oxidation peaks may overlap and lead to false positives. This work describes two different solutions to this problem. On one hand, the modification of disposable carbon sensors with carbon nanotubes allows the voltammetric quantification of cocaine by using ordinary least squares regressions in the concentration range from 10 to 155 μmol L(-1), with a reproducibility of 5.6% (RSD, n = 7. On the other hand, partial least squares regressions are used for the resolution of the overlapped voltammetric signals when using screen-printed carbon electrodes without any modification. Both procedures have been successfully applied to the evaluation of the purity of cocaine street samples.
authors.affiliation: Analytical Chemistry Department, Faculty of Sciences, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Asturias-Arribas
authors.affiliation: Analytical Chemistry Department, Faculty of Sciences, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain,. Electronic address: malomillo@ubu.es.
authors.forename: M Asunción
authors.initials: MA
authors.lastname: Alonso-Lomillo
authors.affiliation: Analytical Chemistry Department, Faculty of Sciences, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Domínguez-Renedo
authors.affiliation: Analytical Chemistry Department, Faculty of Sciences, University of Burgos, Pza. Misael Bañuelos s/n, 09001 Burgos, Spain.
authors.forename: M Julia
authors.initials: MJ
authors.lastname: Arcos-Martínez
mesh_terms: D000082:Acetaminophen / Q000032:analysis; D000779:Anesthetics, Local / Q000032:analysis*; D002110:Caffeine / Q000032:analysis; D003042:Cocaine / Q000032:analysis*; D003061:Codeine / Q000032:analysis; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D016018:Least-Squares Analysis; D057230:Limit of Detection; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000295:instrumentation*
chemical_list: D000779:Anesthetics, Local; D037742:Nanotubes, Carbon; D000082:Acetaminophen; D002110:Caffeine; D003042:Cocaine; D003061:Codeine
keywords: Carbon nanotubes; Cocaine; Partial least squares regression; Screen-printed electrode; Square-wave voltammetry