甲基绿-高碘酸钾系统催化动力学光度法测定痕量铱(Ⅳ)  

Determination of trace iridium (Ⅳ) by catalytic kinetic spectrophotometry with methyl green-potassium periodate system

作　　者：王洪福[1] 张素兰[2] 罗英[2] 何黎明[1] 

机构地区：[1]绵阳师范学院化学与化学工程学院,绵阳621000 [2]绵阳师范学院生命科学与技术学院,绵阳621000

出　　处：《分析试验室》2010年第4期111-114,共4页Chinese Journal of Analysis Laboratory

摘　　要：基于以H3PO4为反应介质,用HAc-NaAc(1+8)(pH5.7)作缓冲溶液,在沸水浴中加热条件下,痕量铱(Ⅳ)能灵敏地催化高碘酸钾氧化甲基绿的褪色反应,建立了一种测定痕量铱(Ⅳ)的新催化光度法。研究了反应的最佳条件。催化反应吸光度A与非催化反应吸光度A0的差值ΔA与铱(Ⅳ)的质量浓度ρ在0～2.0μg/25mL范围内呈良好的线性关系。检出限为2.97×10-10g/mL。对1μg/25mL铱(Ⅳ)测定的相对标准偏差为1.7%(n=11)。测定了动力学参数。该催化反应对铱(Ⅳ)为一级反应,总反应为准一级反应。反应的表观速率常数为4.613×10-4/s,表观活化能为40.56kJ/mol。该方法用于分子筛样品和活性炭中痕量铱(Ⅳ)的测定,回收率97.9%～104.4%。A new catalytic spectrophotometric method for the determination of trace iridium was established based on its catalytic effect on the oxidative fading reaction between methyl green and potassium periodate in H3PO4 and HAc-NaAc (pH 5.7) cushion solution.A linear relationship was obtained between the absorbency difference A of non-catalytic reaction and catalytic reaction and the concentration of Ir(Ⅳ) in the range of 0～2.0 μg/25 mL.The detection limit was 2.969×10-10 g/mL.The relative standard deviation for ...

关 键 词：铱(Ⅳ) KIO4 甲基绿 催化动力学光度法 

分 类 号：O614.825[理学—无机化学]