邻菲罗啉增敏催化动力学光度法测定痕量锰

Determination of Trace Mangan(Ⅱ) by Catalytic Kinetic Spectrophotometric Method With the Enhanced Sensitivity of Phenauthroline

在NH3·H2O-NH4Cl缓冲介质中(pH=10.0),高碘酸钾氧化茜素的褪色反应受锰(Ⅱ)的催化而加速,且活化剂邻菲罗啉使反应更加强烈,据此建立了用催化动力学光度法测定痕量锰的新的指示反应.研究了反应体系的适宜条件和动力学参数,初步探讨了反应机理.结果表明,对于25 mL溶液,本法测定Mn(Ⅱ)的线性范围为0～4.0×10-5 g·L-1,检出限2.4×10-7 g·L-1.应用于蒙药样品中锰的测定,相对标准偏差为1.3%～4.0%,标准加入回收率为95%～105%.

A new catalytic spectrophotometric method for determination of trace Mangan（ Ⅱ ）is developed,which is based on the depigment reaction of potassium periodate with Alizarin in NH3 · H2ONH4 Cl solution buffer medium（pH=10.0）. The existence of Phenauthroline makes the reaction more intense. The optimal condition,kinetic parameter and the reaction mechanism are initially studied. For 25 mL solution,the linear range is 0-4.0×10^-5g · L^-1 ,and the detection limit is 2.4×10^-7g · L^-1. The method has been applied to the determination of Mangan（ Ⅱ ）in Mongolian medicine. The relative standard deviation （RSD） is 1.3%-4.0% and the recovery rate is 95%-105%.