铱(Ⅳ)-偶氮氯膦-mA-高碘酸钾体系催化光度法测定痕量铱  

Catalytic spectrophotometric determination of trace iridium(Ⅳ) using iridium(Ⅳ)-KIO_4-chlorophosphonazo-mA system

作　　者：龙巍然[1] 丁中涛[1] 曹秋娥[1] 

机构地区：[1]教育部自然资源药物化学重点实验室云南大学化学科学与工程学院

出　　处：《冶金分析》2007年第10期40-42,共3页Metallurgical Analysis

摘　　要：在稀硫酸介质中，铱催化高碘酸钾氧化偶氮氯膦-mA褪色，据此建立了测定痕量铱的新催化光度法。研究了催化反应的动力学条件并测定了有关参数。结果表明，本催化反应对于铱㈣和偶氮氯膦-mA均为一级反应，表观活化能Ea=6．912kJ／mol。方法的线性范围为0．0025～0．015μg／mL，检出限为6．38×10^-6μg／mL。除等量的Ru（Ⅲ）和Rh（Ⅲ）干扰（Ⅳ）的测定外，大多数常见金属离子不干扰测定。测定25mL溶液中0．20μgIr（Ⅳ）的相对标准偏差为1．48％（n=11）。本法已用于冶金产品中铱的测定，所得结果与原子吸收光谱法测定结果吻合。A new catalytic spectrophotometric method was developed for the determination of Ir（[V） based on its catalytic effect on the oxidation reaction of chlorophosphonazo-mA（CAP-mA） by KIO4 in the diluted H2SO4 medium. Kinetic parameters were derived and the reaction conditions were stud- ied. The results indicated that the catalytic reaction is first-order for both Ir（[V） and chlorophosphonazo- mA with the apparent activation energy of 6. 912 kJ/mol. The linear range of the method was 0. 002 5 -0. 015 μg/mL for Ir（Ⅳ） with the detection limit of 6.38×10^-6μg/mL. Many of the common ions did not interfere with the determination except for Ru（Ⅲ） and Rh（Ⅲ） at the equal amount as Ir（Ⅳ）. The relative standard deviation was 1.48%（n=11） for the determination of 0.20 μg/25mL Ir（Ⅳ）. The method was applied to the determination of iridium in the metallurgy products, and the results agreed well with those obtained by AAS.

关 键 词：铱 高碘酸钾 偶氮氯膦-MA 催化光度法 

分 类 号：O643.32[理学—物理化学]