偶氮胂Ⅲ催化光度法测定痕量钌

Catalytic spectrophotometric determination of trace ruthenium with arsenazo Ⅲ

在硫酸介质和热水浴 (90± 0 .5℃ )中 ,Ru 催化高碘酸钾氧化偶氮胂Ⅲ (AAⅢ )褪色 ,建立了测定钌的新催化光度法。ΔA与钌质量浓度在 0～ 0 40 μg/ 2 5mL范围内 ,呈线性关系 ,检出限为 9 88× 10 - 5μg/mL。对 0 2 0 μg/ 2 5mLRu 测定的相对标准偏差为 1 3 % (n =11)。催化反应的表观活化能为 12 8 2kJ/mol。催化反应对Ru 和偶氮胂Ⅲ分别为一级反应。试验了 40多种共存离子的影响 ,允许 5 0 0倍量的Au ,Ag+ ,10 0倍量的Pt ,2 5倍量的Pd ,Ir 及Cu2 + 存在。该方法用于岩矿和冶金产品中钌的测定 ,结果满意 ,相对标准偏差为 1 1%～ 2 4% ,标准加入回收率为 10 0 %～ 10 1%。

A new catalytic kinetic method for the determination of ruthenium was established based on the catalytic action of Ru*#on the oxidative fading of arsenazo Ⅲ by KIO 4 in sulfuric acid on the hot water(90±0.5℃) bath The linear relationship between absorbance (ΔΑ) and concentration of ruthenium was in the range of 0-0 40μg/25mL for Ru*#,and the detection limit was 9 88×10 -5 μg/mL The relative standard deviation for 11 replicate measurement of 0 20μg/25mL for Ru*#was 1 30% The apparent activation energy of catalytic reaction was found to be 128 20kJ/mol The reaction is first order both for Ru*#and arsenazo Ⅲ 500 fold amounts of Au*#and Ag +,100 fold amounts of Pt*$,and 25 fold amounts of Pd*',Ir*$and Cu 2+ are admissible The method has been applied to the determination of trace ruthenium in some ores and metallurgical products with the RSD(n=6)over 1 13%-2 43% and the recovery over 100 3%-101 5%