铱-催化高碘酸钾氧化甲基紫动力学光度法测定痕量铱(Ⅳ)  

Determination of Trace Iridium by Catalytic Kinetic Spectrophotometry with Potassium Periodate Oxidatizing Methyl Purple in the Presence of Irodium-catalysis

作　　者：王洪福[1] 魏成富[1] 罗娅君[1] 黎国兰[1] 张玲丽[1] 

机构地区：[1]绵阳师范学院化学与化学工程学院,四川绵阳621000

出　　处：《四川师范大学学报（自然科学版）》2010年第5期672-675,共4页Journal of Sichuan Normal University（Natural Science）

基　　金：四川省教育厅自然科学重点科研基金(07ZA044)资助项目

摘　　要：在稀H2SO4介质中及加热95℃的条件下,痕量铱(Ⅳ)对KIO4氧化甲基紫的褪色反应具有显著催化作用,探讨了最佳实验条件,建立了一个催化动力学光度法测定痕量铱的新分析方法.非催化反应的吸光度A0与催化反应的吸光度A在580nm处的差值ΔA与铱(Ⅳ)质量浓度ρ在0.0～0.06μg/mL范围内呈良好的线性关系,检出限为2.833×10-10g/mL.测定了动力学参数,该催化反应为准一级反应,反应的表观速率常数为1.345×10-3s-1,表观活化能为33.81kJ/mol.方法用于分子筛和活性炭中痕量铱(Ⅳ)的测定,回收率在100.0%～104.2%之间,符合痕量分析的要求.In diluted H2SO4 and heating at 95 ℃,the trace iridium can catalyze discoloured reaction of the potassium periodate oxidatizing methyl purple.According to this phenomenon,a new method using catalytic kinetic spectrophotometry to the determination of iridium has been established.Optimum experimental conditions were discussed and kinetic parameters of this catalytic reaction were determined.The difference of ΔA between non-catalytic reaction absorbency A0 and catalytic reaction absorbency A at 518 nm remains a good linear relationship with ρ,the mass concentration of iridium in the range of 0.0 to 0.06 μg/mL.The detection limit is 2.833 × 10-10 g/mL.The kinetic parameters of this reaction were also determined and the result showed it was a quasi-first-order kinetics reaction.The apparent ratio constant of this reaction was 1.345 × 10-3s-1,and the apparent activation energy of the reaction was 33.81 kJ/mol.The method has been applied to the determination of trace iridium in molecular sieves and active carbon.The recovery ratio was about 100.0% ～ 104.2%,which met the request of the trace analysis.

关 键 词：催化动力学光度法 铱 甲基紫 

分 类 号：O657.32[理学—分析化学]