吐温-80存在下,以5-Br-PADAP作锆(Ⅳ)的光度分析显色剂之研究

Study on 5-Br-PADAP as a spectrophotometric reagent for zirconium(IV) in the presence of Tween-80

2-（5-溴-2-吡啶偶氮）-5-二乙氨基酚（简称5-Br-PADAP或5-Br-DEPAP）系灵敏的有机显色剂,首先合成,已有综述和介绍。邵光均研究了有机-水混合介质中试剂与锆（IV）的光度性质,体系具有较高的灵敏度。本文研究了于pH=3.1的缓冲介质[HCl-C6H4（COO）2HK]中,在吐温-80存在下,锆（IV）与5-Br-PADAP的络合显色反应。络合物呈蓝紫色,其最大吸收波长为585nm。

The colorimetric reaction of zirconium(IV) with 5-Br-PADAP in the presence of Tween 80 has been investigated in this paper. The optimal conditions have been established. A biue violet ternary complex of Zr(IV) with 5-Br-PADAP and Tween-80 is formed in pH 2.6～3.6 medium [HCl-C_6H_4(COO)_2HK]. The complex exhibits maximum absorbance at 585nm with a molar absorptivity coefficient of 1.20×10~5 l·mol^(-1)·cm^(-1). The composition of the complex has been established to be Zr(IV)∶5-Br-PADAP=1∶3. The complex carries positive charge as shown by electrophoresis experiment and its tentative structure is suggested. Beer's law is obeyed up to 4.5μg Zr (IV)/10ml The effect of co-existing ions has been examined.The developed method is simple and rapid and has been used for the analysis of zirconium in Al- alloy with satisfactory results