摘要
本文将荧光光度法与催化动力学相结合,在酸性介质中,铁(Ⅲ)对溴酸钾氧化二氯荧光素的反应具有很强的催化作用,以溴酸钾——二氯荧光素为反应体系,建立了一种测定痕量铁的催化动力学荧光新方法.对催化体系的最优反应条件进行了考察研究,在最优条件下,Fe(Ⅲ)浓度在1 ×10-7～7× 10-6 mg/mL范围内与荧光强度呈良好的线性关系,方法的检出限为6 × 10-8 mg/mL.对浓度为5 × 10-7 mg/mL的Fe(Ⅲ)标准溶液进行11次平行测定,相对标准偏差(RSD)为1.2％.该法简单、快速、灵敏,已用于蔬菜中铁含量的测定,回收率为90％～107.1％,结果令人满意.
Abstract
In this paper,catalytic kinetics and fluorescence spectrophotometry were combined.Based on the catalytic effect of iron(Ⅲ)on the oxidation of dichlorofluorescein by potassium bromate in acid solution,a new catalytic-kinetic fluorometry method for determination of trace iron was proposed with potassium bromate-di-chlorofluorescein as the reaction system.The optimum conditions affecting the catalytic reaction have been inves-tigated.Under the optimal conditions,the iron(Ⅲ)concentration within a range of1 × 107～7 × 10-6 mg/mL has a good linear relation,and the detection limit is 6 × 10-8 mg/mL.The relative standard deviation(RSD)is 1.2％for 5 × 10-7 mg/mL iron(Ⅲ)solution(n=11).The method has the advantages of simplicity and rapid-ity,and has been applied for the detection of iron(Ⅲ)in vegetables.The recoveries between 90％～107.1％are obtained with satisfied results.
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