高碘酸钾催化光度法测定痕量铑

Determination of Trace Rhodium(Ⅲ) by Catalytic Kinetic Spectrophotometry with Potassium Periodate

在磷酸和热水浴中 ,Rh( )催化高碘酸钾氧化二甲基黄褪色 ,由此建立了测定铑的新催化光度法。本方法的线性范围为 0— 4 .0 μg/ 2 5 m L,检出限为 4 .71× 10 -10 g/ m L。对 2 .0 μg/ 2 5 m L Rh( )测定的相对标准偏差为 1.4 3% (n=11) ,催化反应的表观活化能为 12 5 .8k J/ mol。此法已用于某些催化剂和冶金产品中痕量铑的测定 ,结果令人满意。

Based on the catalytic effects of rhodium(Ⅲ) on the oxidation reactions of dimethyl yellow by KIO 4 in the H 3PO 4 medium, a new catalytic spectrophotometric method has been developed for the determination of rhodium(Ⅲ). The good linear relationship has been obtained in the concentration range of Rh(Ⅲ) over 0-4 0μg/25mL with a detection limit of 4 71×10 -10 g/mL. The relative standard deviation for the determination of Rh(Ⅲ) at the concentration of 2 0μg/25mL was calculated as 1 43%( n =11). The apparent activation energy of this reaction is 125 8kJ/mol. The method has been successfully applied to the determination of rhodium(Ⅲ) in catalysts and platinum metal samples.