催化光度法测定锰(Ⅱ)的研究

Study on Determination of Manganese(Ⅱ) by Catalytic Spectrophotometry

在pH3.5的NaAc-HAc缓冲介质中,溴酸钾氧化碘化钾生成单质碘,锰(Ⅱ)对这一显色反应具有显著的催化作用。据此,建立了催化光度法分析测定环境中痕量锰()的新方法。在优化条件下,于最大吸收波长220nm处进行测定,锰(Ⅱ)浓度在1.0×10-8—1.0×10-7mol/L范围内呈现良好的线性关系;检出限为6.0×10-9mol/L(3σ);对1.0×10-7mol/L的锰(Ⅱ)进行了平行测定(n=11),其相对标准偏差为2.4%;考察了多种共存离子的影响。将此法应用于水样中锰(Ⅱ)的测定,回收率在96.9%—97.8%之间,结果满意。

A new catalytic spectrophotometry method for the determination of trace amounts of manganese（Ⅱ） in environment was developed based on the significant catalytic action of trace manganese on the oxidative color reaction of potassium bromate and potassium iodide in HAc-NaAc buffer solutions at pH 3.5.Under the optimum conditions,the absorbance intensity at 220nm was proportional to the concentration of Mn（II） with good linearity in the range of 1.0×10-8—1.0×10-7mol/L.Detection limit is 6.0×10-9mol/L for manganese（Ⅱ）.The RSD is 2.4% at 1.0×10-7mol/L（n=11）.The interference of coexist ion was studied.The method was applied to the determination of manganese（Ⅱ） in water sample with the recovery of 96.9%—97.8%.The result is satisfied.