钨(Ⅵ)-4(6-溴-2-苯并噻唑偶氮)邻苯二酚-乳化剂OP三元络合物显色反应的研究及其应用

Chromogenic Reaction for Tungsten (Ⅵ)-4-(6-Bromo-2-benzothiazolylazo)pyrocatechol-Emulsifier OP Micellar Complex and Its Application

非离子表面活性剂OP存在下，钨（Ⅵ）与新显色剂4-（6-溴-2-苯并噻唑偶氮）邻苯二酚（6-Br-BTAPC）在pH4.0～5.2介质中反应形成稳定的、带负电荷的、紫红色三元胶束络合物。其中W（Ⅵ）与6-Br-BTAPC的组成比为1∶2；λmax为558nm，表现ε558为7.34X104L·mol-1·cm-1。钨（Ⅵ）含量在0～1.4mg／L范围内遵从比耳定律。建议了络合物的结构。将拟定的分析方法用于合金钢试样中小量或痕量钨的测定，取得了满意的结果。

In the presence of OP, a non-ionic surfactant, W(Ⅵ ) sensitively reacts with 4-(6-bromo-2-benzothiazolylazo) pyrocatechol (6-Br-BTAPC), a new chromogenic reagent, to form a stable, negatively charged, violet-red, ternary micellar complex in the pH range of 4.0 to 5. 2. The ratio between W(Ⅵ ) and 6-Br-BTAPC in the complex is 1: 2 with λmax 558nm, contrast (QA) 118 nm, apparent stability constant 3. 7 X 109 and apparent ε558 7. 34 X 104L. mol-1. cm-1 in 20℃ and pH 5. 0. Beer's law is obeyed in the range of 0 to 1. 4 mg/L of W (Ⅵ). The effect of many coexisting ions on the chromogenic reaction was studied. The chromogenic reaction not only has high sensitivity, but also higher selectivity. The structure of the complex was suggested. Satisfactory results have been achieved in applying this analytical method to the daermination of trace or minor tungsten in alloy steel.