过硫酸钾氧化刚果红褪色催化光度法测定水中微量镍

Catalytic spectrophotometric determination of trace nickelⅡ in water based on discoloring reaction of congo red by oxidation of potassium persulfate

基于pH9·2的NH3·H2O-NH4Cl介质中,微量镍Ⅱ催化过硫酸钾氧化刚果红的褪色反应,建立了测定微量镍Ⅱ的催化光度法。讨论了酸度、反应物浓度、反应温度、时间、干扰离子等因素的影响,确定了反应的最佳条件,并测定了一些动力学参数。催化反应的表观活化能为66·19kJ/mol。方法检出限为2·52×10-6g/L,线性范围为0·004～0·32mg/L。用于河水、井水、污水中微量镍Ⅱ的测定,回收率在97·1%～103·0%,相对标准偏差为2·3%～4·3%。

Based on the catalytic effect of trace nickel（ID on discoloring reaction of congo red with potassium persulfate in NH3·H2O-NH4Cl（pH 9.2） ,a method for the determination of trace nickel（ID by kinetic spectrophotometry was established. The factors such as acidity,concentration of reactants, reaction time, temperature, influence of coexisting ions on the reaction and the optimum conditions of reaction were examined and some kinetic parameters were determined. The apparent activation energy of the reaction is 66.19 kJ/mol. The detection limit is 2.52 × 10^-6 g/L and the linear range of determination is 0. 004-0.32 mg/L for nickel（ID. The method has been applied to the determination of trace nickel（Ⅱ） in river water,well water and polluted water samples with the recovery of 97.1%-103.0%, the RSD of 2.3%-4.3% （n =6）.