孔雀石绿-H_2O_2体系动力学光度法测定微量溴化物

Kinetic-spectrophotometric method for the determination of trace amount of bromide with malachite green-hydrogen peroxide

基于在NH3-NH4Cl介质中,Br-对H2O2氧化孔雀石绿的褪色反应有催化作用的特性,建立了高灵敏度测定痕量溴化物的催化动力学光度分析法新体系。讨论了酸度、试剂用量、温度、干扰离子等因素的影响。研究了反应的最佳条件,测定了一些动力学参数,非催化反应和催化反应的的表观活化能分别为为52.85和19.53kJ/mol。方法的线性范围为0.10～1.2μg/mLBr-,检出限为0.081μg/mL。方法用于水样中溴化物的测定,结果与国标分析法所得结果相吻合。

An accurate method for the determination of bromide by kinetic spectrophotometry was established based on the catalytic effect of bromide on the discoloring reaction of Malachite green with hydrogen peroxide in the medium of NH3-NH4Cl buffer. The influence of acidity, amounts of reagents, temperature and other factors on the reaction were discussed. The optimum conditions of the reaction and some kinetic parameters were determined. The apparent active energies of the non-catalytic reaction and the catalytic reaction were 52.85 and 19.53 kJ/mol respectively. The linear range was 0.10- 1.2 μg/mL for bromide, and the detection limit was 0.081 μg/mL. The proposed method has been applied successfully to the determination of trace bromide in water samples, and the results are in agreement with those obtained by the standard method.