Produção Nacional
Revisado por pares
Voltammetric determination of cocaine in confiscated samples using a cobalt hexacyanoferrate film-modified electrode
2009; Elsevier BV; Volume: 192; Issue: 1-3 Linguagem: Inglês
10.1016/j.forsciint.2009.08.004
ISSN1872-6283
AutoresÉrica Naomi Oiye, Natália Biziak de Figueiredo, José Fernando de Andrade, Heloísa Maria Tristão, Marcelo Firmino de Oliveira,
Tópico(s)Electrochemical sensors and biosensors
ResumoIn this work, a fast, non destructive voltammetric method for cocaine detection in acetonitrile medium using a platinum disk electrode chemically modified with cobalt-hexacyanoferrate (CoHCFe) film is described. The deposition of CoHCFe film at platinum disk (working electrode) was carried out in aqueous solution containing NaClO4 at 0.1 mol L−1 as supporting electrolite. Stability studies of the film and subsequent voltammetric analysis of cocaine were made in acetonitrile medium with NaClO4 at 0.1 mol L−1 as supporting electrolite. A reversible interaction between cocaine and CoHCFe at the film produces a proportional decrease of original peak current, due to the formation of a complex between cocaine and cobalt íons, with subsequent partial passivation of the film surface, being the intensity of current decrease used as analytical signal for cocaine. A linear dependence of cocaine detection was carried out in the range from 2.4 × 10−4 to 1.5 × 10−3 mol L−1, with a linear correlation coefficient of 0.994 and a detection limit of 1.4 × 10−4 mol L−1. The analysis of confiscated samples by the proposed method indicated cocaine levels from 37% to 95% (m/m) and these results were validated by comparison to HPLC technique, being obtained good correlation between both methods.
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