高碘酸钾氧化中性红催化光度法测定痕量铱

Catalytic spectrophotometric determiantion of trace iridium with the oxidation of neutral red by KIO_4

在稀硫酸介质中 ,铱催化高碘酸钾氧化中性红 (NR)褪色 ,据此建立了测定痕量铱的新催化光度法。本法线性范围为 0～2 4× 1 0 -3 μg mL ,检出限为 9.2× 1 0 -5μg mL。对 0 .0 50 μgIr(Ⅳ )测定的相对标准偏差为 1 .3% (n =1 0 )。考察了 40多种共存离子的影响 ,允许 50倍量的Ru(Ⅲ ) ,50 0倍量的Au(Ⅲ ) ,2 50 0倍量的Pt(Ⅳ )、Pd(Ⅱ )及Rh(Ⅲ )存在。本法已用于冶金产品及岩矿中铱的测定 ,其相对标准偏差为 1 .1 %～2 .4% ,标准加入回收率为 97.8%～1 0 2 .6%。

A new catalytic spectrophotometric method was developed for the determinations of Ir(Ⅳ) based on its catalytic effects on the oxidation reactions of neutral red (NR) by KIO_4 in the diluted H_2SO_4 medium. The linear range for the determination of Ir(Ⅳ) by this system was 0.0～0.060 μg/25 mL with the detection limit of 9.20×10^(-5) μg/mL. The relative standard deviation for the determinations of 0.050 μg Ir(Ⅳ) was 1.32%(n=10). The results obtained from the studies on the effects of more than 40 foreign ions indicated that that 50-fold of Ru(Ⅲ), 500-fold of Au(Ⅲ), 2500-fold of Pt(Ⅳ), Pd(Ⅱ) and Rh(Ⅲ) did not interfere in the determination of Ir(Ⅳ). The method was applied to the determination of iridium in the metallurgy products and ore samples with the relative standard deviation over 1.13%～2.43% and the recovery over 97 8%～102.6%.