钴(Ⅱ)催化过氧化氢氧化5-Br-TAMB的褪色反应动力学及其应用

The Study on Catalytic Kinetic Spectrophotometric Determination of Trace Cobalt with 5-Br-TAMB

研究了NaAc-HAc介质中钴(Ⅱ)催化H_2O_2氧化5-Br-TAMB的褪色的反应,测定了反应动力学参数,探讨了反应机理,并建立了测定痕量钴的新方法。本法检出限为1.8×10^(-10)g/mL,钴(Ⅱ)浓度在0～124.7 ng/12.5 mL范围内与1g(A_0/A)呈良好的线性关系。该体系已用于人发、茶叶中钴的测定,结果满意。

It was found that the decoloring reaction of 2-[2-(5-bromothiazoly)azo]-5-dimethylaminobenzoic acid (5-Br-TAMB) by hydrogen peroxide oxidation could be catalyzed by trace Co(Ⅱ) in pH 4～7 HAc-NaAc solution. The order of the reaction and the apparent activation energy have been determined and reaction mechanism has heen discussed. According to obove results, new method with high sensitivity and selectivity for determining trace Co(Ⅱ) was established. The detection limit was 1.8×10^(10)g/mL. The linear range was 0～124.7 ng/12.5mL. The method has been applied to the determination of Co (Ⅱ) in samples with satisfactory results.