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Unraveling the Mechanisms Behind the Complete Suppression of Cocaine Electrochemical Signals by Chlorpromazine, Promethazine, Procaine, and Dextromethorphan.
de Jong, Mats; Sleegers, Nick; Florea, Anca; Van Loon, Joren; van Nuijs, Alexander L N; Samyn, Nele; De Wael, Karolien.
Afiliación
  • de Jong M; AXES Research Group , University of Antwerp , Groenenborgerlaan 171 , 2020 Antwerp , Belgium.
  • Sleegers N; AXES Research Group , University of Antwerp , Groenenborgerlaan 171 , 2020 Antwerp , Belgium.
  • Florea A; AXES Research Group , University of Antwerp , Groenenborgerlaan 171 , 2020 Antwerp , Belgium.
  • Van Loon J; AXES Research Group , University of Antwerp , Groenenborgerlaan 171 , 2020 Antwerp , Belgium.
  • van Nuijs ALN; Product Development Research Group , University of Antwerp , Ambtmanstraat 1 , 2000 Antwerp , Belgium.
  • Samyn N; Toxicological Center , University of Antwerp , Universiteitsplein 1 , 2610 Antwerp , Belgium.
  • De Wael K; Drugs and Toxicology Department , National Institute for Criminalistics and Criminology , Vilvoordsesteenweg 100 , 1120 Brussels , Belgium.
Anal Chem ; 91(24): 15453-15460, 2019 12 17.
Article en En | MEDLINE | ID: mdl-31724391
The present work investigates the challenges accompanied by the electrochemical cocaine detection in physiological conditions (pH 7) in the presence of chlorpromazine, promethazine, procaine, and dextromethorphan, frequently used cutting agents in cocaine street samples. The problem translates into the absence of the cocaine oxidation signal (signal suppression) when in a mixture with one of these compounds, leading to false negative results. Although a solution to this problem was provided through earlier experiments of our group, the mechanisms behind the suppression are now fundamentally investigated via electrochemical and liquid chromatography quadrupole-time-of-flight mass spectrometry (LC-QTOF-MS) strategies. The latter was used to confirm the passivation of the electrodes due to their interaction with promethazine and chlorpromazine. Electron transfer mechanisms were further identified via linear sweep voltammetry. Next, adsorption experiments were performed on the graphite screen printed electrodes both with and without potential assistance in order to confirm if the suppression of the cocaine signals is due to passivation induced by the cutting agents or their oxidized products. The proposed strategies allowed us to identify the mechanisms of cocaine suppression for each cutting agent mentioned. Suppression due to procaine and dextromethorphan is caused by fouling of the electrode surface by their oxidized forms, while for chlorpromazine and promethazine the suppression of the cocaine signal is related to the strong adsorption of these (nonoxidized) cutting agents onto the graphite electrode surface. These findings provide fundamental insights in possible suppression and other interfering mechanisms using electrochemistry in general not only in the drug detection sector.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Procaína / Prometazina / Clorpromazina / Cocaína / Dextrometorfano / Técnicas Electroquímicas Tipo de estudio: Diagnostic_studies / Prognostic_studies Idioma: En Revista: Anal Chem Año: 2019 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Estados Unidos
Texto completo
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Procaína / Prometazina / Clorpromazina / Cocaína / Dextrometorfano / Técnicas Electroquímicas Tipo de estudio: Diagnostic_studies / Prognostic_studies Idioma: En Revista: Anal Chem Año: 2019 Tipo del documento: Article País de afiliación: Bélgica Pais de publicación: Estados Unidos