亮绿SF-高碘酸钾催化动力学光度法测定痕量铈  

Determination of Trace Cerium by Catalytic Kinetic Spectrophotometry withLight Green SF and Potassium Periodate

作　　者：谢建鹰[1] 雷明建 

机构地区：[1]上饶师范学院化学化工学院,江西上饶334001 [2]江西省煤田地质局226地质队,江西萍乡33700

出　　处：《稀土》2013年第3期55-58,共4页Chinese Rare Earths

基　　金：教育部第四批高等学校特色专业建设点资助项目(TS11524);江西省自然科学基金资助项目(0420025)

摘　　要：在pH值为4.5的HAc-NaAc缓冲溶液介质中,以硫脲为活化剂,痕量铈(Ⅳ)可催化高碘酸钾氧化亮绿SF褪色反应。据此,建立了催化动力学光度法测定痕量铈的新方法。考察了介质、试剂用量、反应温度、反应时间及共存离子的影响,确定了测定波长为632 nm等最佳实验条件。在选定的实验条件下,测得反应的表观活化能为91.2 kJ/mol,常见元素不干扰测定;Ce(Ⅳ)的质量浓度在0～0.18μg/mL范围内与lg(A0/A)呈良好的线性关系,方法的检出限为5.04×10-10g/mL。用于粮食样品中痕量铈的分析,6次测定的标准偏差≤7.65%,样品加标准回收率在94.4%～103.3%。A new catalytic kinetic spectrophotometry for the determination of trace cerium has been established.The method is based on the catalytic effect of trace cerium（Ⅳ） on the oxidizing discoloring reaction of light green SF with potassium periodate using thiourea as an activator in HAc-NaAc buffer solution at pH=4.5.The influence of medium,reagent dosage,reaction temperature,reaction time and coexisting ions on the determination were investigated.The detection wavelength was selected as 632 nm with optimal conditions.Under the optimal conditions,the apparent activation energy of the catalytic reaction was 91.2 kJ/mol.Most common ions did not interfere in the determination.There was a good linear relationship between the concentration of Ce（Ⅳ） and lg（A0/A） in the content range of 0 to 0.18 μg/mL.The detection limit of this method was 5.04×10^-10 g/mL.The proposed method was applied to the determination of trace cerium in grain samples.The relative standard deviation was less than or equal to 7.65%（n=6）,and the recoveries of standard addition were 94.4%～103.3%.The method is simple,sensitive,and accurate.The accuracies of the experiment meet the requirements for common grain sample analysis.

关 键 词：亮绿SF 催化动力学光度法 高碘酸钾 铈 

分 类 号：O657.32[理学—分析化学]