【摘要】 <正> 近年来,杂环偶氮苯甲酸类显色剂取得了较快的发展。由于氨基取代结构对试剂性能有较大的影响,因此本文合成了新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸,(TAEB)并研究了它与钴的显色反应。 实验表明,在非离子表面活性剂存在下,钴与TAEB配合物的吸收峰位于673nm,更多还原

【Abstract】 2-(2-Thiazolylazo)-5-diethylaminobenzoic acid (TAEB) was synthesized and studied as a new reagent for the spectrophotometric determination of trace amount of cobalt. Its acid dissociation constants both in the absence and in the presence of Triton X-100 were determined. In a pH 2.6-4.8 medium TAEB reacts with cobalt (Ⅲ) ions to form a stable complex, exhibiting an absorption maximum at 672nm. The molar absorptivity was found to be 1.26×105 dm3·mol-1·cm-1. The constituent of the complex was established as Co: TAEB =1:3. Interference from copper, nickel, iron and chromium ions and etc. can be eliminated by acidification with HCl after cobalt complex is formed. The method has been used for the determination of trace cobalt in steel and iron directly with satisfactory results.更多还原