催化褪色光度法测定痕量钍(Ⅳ)

DETERMINATION OF TRACE THORIUM(Ⅳ) BY CATALYTIC KINETIC DISCOLORING SPECTROPHOTOMETRY

在HNO3介质中,以Th(Ⅳ)作活化剂,Fe(Ⅲ)催化KIO4氧化偶氮胂Ⅲ褪色为指示反应,建立了痕量Th(Ⅳ)的动力学分析方法。本方法测定范围为0-5.0μgTh(Ⅳ)/25mL,检出限为2.41×10-8gTh(Ⅳ)/mL,应用于土壤中痕量Th(Ⅳ)的测定,结果满意。

It has been found that Fe(Ⅲ) can catelyze the discoloration of arsenazo Ⅲ by potassium periodate in nitric,while Th(Ⅳ) acts as a promoter.The kinetic conditions of this reaction have been studied,a new method for the determination of trace Thorium(Ⅳ) is proposed.Its linear range is 0-5.0 μg/25 mL Th(Ⅳ) and the detection limit is 2.41×10^(-8) g/mL Th(Ⅳ).It has been applied satisfactorily to the determination of the trace Th(Ⅳ) in soil sample.