中文摘要：

在pH 4.5的NaAc-HAc缓冲介质中,以邻菲咯啉（phen）作活化剂,痕量Fe（Ⅲ）对H2O2氧化茜素红S（ARS）的褪色反应存在明显的催化作用,由此建立了测定痕量铁（Ⅲ）的催化动力学光度法.采用固定时间法,在λmax=422 nm处,对催化体系和非催化体系进行光度测定,应用了正交试验法确定最佳条件,测定了有关动力学参数.该方法的检出限为0.63μg/L;线性范围为0～20μg/L,应用于一次蒸馏水、分析纯盐酸中痕量铁的测定,结果令人满意.提出了Fe（Ⅲ）-ARS-phen三元络合物活性中间体的催化反应机理设想,并推测催化反应经历了羟自由基氧化反应的历程.

英文摘要：

A new catalytic kinetic spectrophotometric method was studied for the determination of trace iron （Ⅲ） based on the remarkable catalytic effect of iron（Ⅲ ） on the oxidation of alizarin S （ARS） by hydrogen peroxide with 1,10-phenanthroline （phen） as activating agent in HAc-NaAc buffer solution （ pH 4.5 ）. Indicator reaction is followed spectrophotometrically by measuring the absorbance change at λmax=422 nm and constant temperature （87℃±0.5℃） by fixed time method. Experimental conditions were optimized by orthogonal test and the kinetic parameters were calculated. The detection limit is 0.63μg/L, and the linear range is 0 -20μg/L. The method has been successfully applied to the determination of trace iron （Ⅲ） in distilled water and analytical pure hydrochloric acid. The mechanism of this reaction was deemed to. form a mixed-ligand complex with the formation of Fe（Ⅲ） （phen） （ARS）2. And the catalytic oxidation reaction was considered as a radical reaction of hydroxyl radicals.