2-羟基-3-羧基-5-磺基偶氮胂的合成及光度法测定钍的研究

Synthesis of arsenazo-HKS and its application in photometric determination of thorium

研究了 2 -羟基 - 3-羧基 - 5 -磺基偶氮胂的合成及光度法测定钍的方法。在 1 .2 mol/L硝酸介质中 ,钍与 2 -羟基 -3-羧基 - 5 -磺基偶氮胂形成 1∶ 2的绿色配合物 ,最大吸收波长在 6 75 nm处 ,摩尔吸光系数为 8.5 4× 1 0 4 L· mol- 1·cm- 1 。钍含量在 0～ 30 μg/2 5 m L范围内符合比耳定律。应用于特种镁合金中钍的直接测定 ,结果非常满意。

In this paper,the synthesis of arsenazo HKS is reported and its reaction with Th has been studied.In a 1.2 mol/L HNO 3 medium,Th(Ⅳ) reacts with arsenazo HKS to form a 1∶2 blue complex having a maximum absorption at 675nm.Its molar absorptivity is 8.54 ×10 4L·mol -1 ·cm -1 .Beer′s law is obeyed for 0~30 μg Th (Ⅳ) in 25 mL.This method has been applied to the determination of Th (Ⅳ) in magnesium alloy samples.