Determinação de parabenos em antitranspirantes empregando voltametria sob eletrodo de diamante e cromatografia liquida de alta eficiencia / Determination of parabens in antiperspirants using voltammetry on boron-doped diamond electrodes and high-performance liquid chromatography

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Esters of p-hydroxybenzoic acid, as methylparaben (MePa), ethylparaben (EtPa) and propylparaben (PrPa) have been widely used as chemical preservatives in cosmetics, drugs, foods, and others. As these compounds are linked with allergies, dermatitis and estrogenic properties, it is necessary to control the concentration of these substances in the different matrices. The ANVISA establish a maximum concentration of 0.8 % w/w of total parabens in cosmetics. The aims of this work were the study of the electrochemical behavior of parabens on the boron-doped diamond electrode and the development of a voltammetric method for the determination of parabens in antiperspirants (roll-on). The optimized voltammetric conditions established were: cyclic voltammetry; supporting electrolyte, phosphate buffer 0.1 mol L, pH 7.0; scan rate, 50 mV s. At these conditions, the parabens undergo oxidation at 0.85 V versus Ag/AgCl, KCl sat. The process is irreversible and diffusion controlled. The sample preparation was carried out using solid phase extraction and the total paraben quantitation was done using hydroquinone as internal standard. The accuracy of the method was evaluated through comparison of results obtained from analyses of antiperspirants by the proposed voltammetric method with those obtained by high performance liquid chromatography. All samples analyzed (12 samples of different manufactures) presented a content of total parabens lower than 0.38 % w/w. The presence of parabens in six samples was not correctly specified at the label

ASSUNTO(S)

voltammetry cromatografia liquida de alta eficiencia eletrodo de diamante dopado com boro parabens parabenos voltametria high performance liquid chromatography boron-doped diamond electrodes

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