新试剂AsA-TB光度法测定建材中的钍

Photometric determination of thorium in building material with a new reagent AsA-TB

目的 :研究了显色剂三溴偶氮胂 (AsA -TB)与Th4+ 的显色反应 ,建立了一种测定建材中微量钍的光度法。方法 :在HCL和H2 C2 O4介质中 ,AsA -TB与Th4+ 生成蓝色络合物 ,最大吸收波长位于 65 0nm ,试剂的最大吸收波长位于5 80nm ,表观摩尔吸光系数值为 1 0× 10 5L/mol·cm ,钍含量在 4～ 3 0 μg/ 2 5ml范围内 ,符合比耳定律。结果 :此方法选择性高 ,大量常见的金属离子以及铀、稀土不干扰钍的测定。结论 :用于建材中钍分析时可不经分离而直接进行 ,结果满意。

Objective:new chromogenic reagent AsA-TB was used in thephotometric determination of thorium in building material Methods:In a HCI and H 2C 2O 4 medium ,Th(IV) reacts with AsA-TB to form a blue complex having its absorption maxima at 650 nm , While the absorption maxima of the reagent itself lies at 580 nm The apparent molar absorptiyity of the Th 4+ -complex is found to be 1 0×10 5 L/mol·cm Beer′s law is obeyed in the range of 4～ 30 μg of Th(Ⅳ) per 25 ml of solution Results:Most of common existing ions, especially uranium and rare earth elements, did not interfere with the determination Conclusion:The above reaction has been satisfactorily applied to the determination of thorium in building material [