da Silva Andrea Pieretti, Trindade Magno Aparecido Gonçalves, Ferreira Valdir Souza
Department of Chemistry, CCET, Universidade Federal de Mato do Grosso Sul, Av. Filinto Muller 1555, Campo Grande, MS, Brazil.
Talanta. 2006 Jan 15;68(3):679-85. doi: 10.1016/j.talanta.2005.05.007. Epub 2005 Jul 7.
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.
本文介绍了一种基于滴汞电极电化学还原的简单、快速且可靠的差分脉冲极谱电分析方法。该方法已针对商业化妆品制剂样品中单独的2-乙基己基-4-甲氧基肉桂酸酯（EHMC）以及与4-甲基亚苄基樟脑（MBC）或2-羟基-4-甲氧基二苯甲酮（BENZ-3）联合使用进行了验证。用于测定EHMC时能提供定义最清晰、峰电流最强的支持电解质是在阳离子表面活性剂存在下的Britton-Robinson缓冲液（pH 4.0）。在优化条件下，相对于Ag/AgCl，EHMC在-1.49 V处呈现一个单一的还原峰。纯EHMC标准品的检测限为3.76×10⁻⁸ mol L⁻¹，定量限为1.25×10⁻⁷ mol L⁻¹。对所有分析的样品均达到了良好的平均回收率。
