de Oliveira Fabio Santos, Korn Mauro
Instituto de Química, Universidade Federal da Bahia, Campus Universitário de Ondina, Salvador, BA, Brazil.
Talanta. 2006 Jan 15;68(3):992-9. doi: 10.1016/j.talanta.2005.06.055. Epub 2005 Aug 11.
A sensitive SIA method was developed for sulphate determination in automotive fuel ethanol. This method was based on the reaction of sulphate with barium-dimethylsulphonazo(III) leading to a decrease on the magnitude of analytical signal monitored at 665 nm. Alcohol fuel samples were previously burned up to avoid matrix effects for sulphate determinations. Binary sampling and stop-flow strategies were used to increase the sensitivity of the method. The optimization of analytical parameter was performed by response surface method using Box-Behnker and central composite designs. The proposed sequential flow procedure permits to determine up to 10.0mg SO(4)(2-)l(-1) with R.S.D. <2.5% and limit of detection of 0.27 mg l(-1). The method has been successfully applied for sulphate determination in automotive fuel alcohol and the results agreed with the reference volumetric method. In the optimized condition the SIA system carried out 27 samples per hour.
开发了一种灵敏的流动注射分析法（SIA）用于测定汽车燃料乙醇中的硫酸盐。该方法基于硫酸盐与钡-二甲基磺酸钠（III）的反应，导致在665nm处监测的分析信号强度降低。酒精燃料样品预先燃烧以避免在测定硫酸盐时产生基体效应。采用二元采样和停流策略来提高该方法的灵敏度。使用Box-Behnker和中心复合设计的响应面法对分析参数进行了优化。所提出的顺序流动程序能够测定高达10.0mg SO(4)(2-)l(-1)，相对标准偏差（R.S.D.）<2.5%，检测限为0.27mg l(-1)。该方法已成功应用于汽车燃料酒精中硫酸盐的测定，结果与参考容量法一致。在优化条件下，流动注射分析系统每小时可处理27个样品。
