一个测定铑的新催化光度法研究

A Study of a New Catalytic Spectrophotometric Method for the Determination of Rhodium

在H2SO4介质和Tween-80存在下，Rh（Ⅲ）对KIO4氧化一个新试剂：5-（4-氯苯基偶氮）-8-苯磺酰胺喹啉的褪色反应具有催化作用，由此建立了一个测定铑的催化褪色光度法．在选定的条件下，方法对铑测定的线性范围为0．1-1．75μg／25mL，检出限（按3Sb／k计算）为2．4×10^-6g／L，且等量的大部分常见金属离子包括部分贵金属离子不干扰测定．将该方法用于催化剂和冶金产品中痕量铑的测定，相对标准偏差为2．2％～1．6％，回收率为98．9％-102．9％．

Based on the catalytic effect of Rh （ Ⅲ ） on the fade reaction of 5 - （4 - chlorophenylazo） - 8 - benzenesulfonamidoquinoline（CPBSQ） oxidized by potassium periodate in the medium of sulfuric acid, a catalytic speetrophotometric method for the determination of trace rhodium has been tested and established. The linear range of the method for the determination of Rh（ Ⅲ ） is 0.1 - 1.75 μg/25 mL with the detection limit of 2.4 - 10^-6 g/L A lot of common ions including some noble metal ions do not interfere the determination at the concentration equal to that of Rh （Ⅲ ）. The method has been used for the determination of trace rhodium in catalyst and metallurgical products with the relative standard deviation over 2.2% - 1.6% and the recovery over 98.9% - 102.9%.