【摘要】 在HCl介质和90℃加热条件下,铱(Ⅳ)对高碘酸钾氧化孔雀绿褪色反应有显著的催化作用,探讨了该催化反应的最佳优化条件,据此建立了催化动力学光度法测定痕量铱(Ⅳ)的新方法.在选定的实验条件下,非催化体系和催化体系的吸光度差值△A与铱(Ⅳ)的质量浓度在0.0-2.5μg.(25 mL)-1范围内呈线性关系,其检出限为7.63×10-10g.mL-1.测定了催化反应的动力学参数,该反应为准一级反应,反应的表观活化能为107.88 kJ.mol-1,在90℃下表观速率常数为7.45×10-4s-1.该方法简便快捷,灵敏度高,选择性好,用于分子筛催化剂和活性碳样品中铱的含量测定,其回收率在99.0%-108%之间,符合痕量分析的要求.更多还原

【Abstract】 This paper discusses the catalytic kinetic spectro-photometric determination of trace iridium(IV).The depigmentation reaction of potassium periodate oxidazing malachite green can be greatly catalyzed by iridium(IV) in HCI and 90 ℃ water condition.According to this phenomenon,a new method of catalytic kinetic photometric determination of trace iridium(IV) has been established.Absorbency difference △A and iridium(IV) mass concentration show a good linear relationship in 0.0-2.5 μg·(25 mL)-1,and the detection limit is 7.63×10-10 g·mL-1.The dynamic parameters are also measured and show that this reaction matches pseudo first order reaction.The apparent activation energy is 107.88 kJ·mol-1 and the apparent rate constant is 7.45×10-4 s-1.This method is of good selectivity and high sensitivity.It has been applied to the determination of iridium in molecular sieve,and got a recovery rate between 99.0%-108%,which meets the request of trace analysis.更多还原