新显色剂二溴邻硝基偶氮胂的合成及其与钍显色反应的研究

Synthesis of a new chromogenic reagent dibromo-o-nitro-arsenazo and its color reaction with thorium

报道了新显色剂二溴邻硝基偶氮肿的合成方法,并研究了试剂与钍的显色反应。在0.12～1mol·L^(-1)HCl 介质中试剂与钍形成蓝色配合物。最大吸收在640nm 处。摩尔吸光率为9.7×10~4L·mol^(-1)·cm^(-1)。Th 在0～8μg/25mL 符合比耳定律。试剂对稀土、铀有很好的抗干扰能力。

The method of synthesis of the new chromo-genic reagent dibromo-o-nitro-arsenazo and theconditions of its color reaction with thoriumhave been investigated.The reagent forms ablue complex with thorium in 1 mol/L HCl me-dium,having a maximum absorption at 640nmwith an apparent molar absorptivity of 9.7×10~4L·mol^(-1)·cm^(-1).The color reaction has goodselectivity.The reagent shows better selectivitytoward uranium and rare earths as comparedwith the commonly used reagents and can beutilized for the spectrophotometric determinationof thorium in the presence of uranium and rareearths.