2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸与镍显色反应的研究

Color Reaction of 2-(5-Carboxy-1,3,4-triazolylazo)-5-diethylamino Benzoic Acid with Nickel

研究了显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(简称CTZDBA)与镍的显色反应。结果表明,在pH5.0的HAc-NaAc缓冲溶液中,Ni2+与CTZDBA形成组成比为1∶2的紫红色络合物,络合物的最大吸收波长为562nm,表观摩尔吸光系数为3.67×104L.mol-1.cm-1。Ni2+质量浓度在(0～0.8)mg/L范围内符合比尔定律。该显色剂有良好的选择性,方法可以不经分离直接测定镍催化剂中镍的含量,加标回收率分别为在97.5%～104.8%之间,RSD(n=6)为1.26%。

Optimum conditions of the colour reaction of 2- （ 5-carboxy- 1,3,4-triazolylazo ）-5-diethylamino benzoic acid （ abbreviated as CTZDBA） with Ni^2＋ are reported. It were found that the colour reagent reacts with Ni （Ⅱ） to form a stable purple red complex （2：1） in the buffer solution of HAc-NaAc with pH 5.0. The maximum absorption wavelength and apparent molar absorptivity were found to be 562 nm and 3.67×10^4L·mol^-1·cm^-1 , respectively. Beer＇s law was obeyed in the rang of （0 -0. 8） mg/L of Ni（Ⅱ）. The method has been applied to the direct determination of nickel in nickel catalyst with satisfactory result. The recovery of standard addition is 97.5% 104. 8% ,with precision of 1.26% （RSD,n =6）.