Polarographic determination of sunscreen agents in cosmetic products in micellar media.
This paper introduces a simple, fast and reliable electroanalytical method for differential-pulse polarography based on electrochemical reduction at a dropping mercury electrode. The method was validated for the determination of 2-ethylhexyl-4-methoxycinnamate (EHMC) alone and in association with 4-methylbenzylidene camphor (MBC) or 2-hydroxy-4-methoxybenzophenone (BENZ-3) in samples of commercial cosmetic preparations. The supporting electrolyte that provided the best-defined and most intense peak current for EHMC determination was Britton-Robinson buffer (pH 4.0) in the presence of a cationic surfactant. Under optimized conditions, EHMC exhibited one single peak of reduction at -1.49 V versus Ag/AgCl. A limit of detection of 3.76 x 10(-8)mol L(-1) and a limit of quantitation of 1.25 x 10(-7) mol L(-1) were found for the pure EHMC standard. A good average recovery rate was reached for all the samples analyzed.
da Silva
Andrea Pieretti
AP
Department of Chemistry, CCET, Universidade Federal de Mato do Grosso Sul, Av. Filinto Muller 1555, Campo Grande, MS, Brazil.
Trindade
Magno Aparecido Gonçalves
MA
Ferreira
Valdir Souza
VS