摘要
研究了3,5-diCl-PADMA与Rh(Ⅲ)的显色反应。在pH4.0～5.2试剂与Rh(Ⅲ)形成稳定的紫红色络合物。再提高盐酸溶液酸度至0.72～6.0mol·L^(-1),其最大吸收峰红移至614nm,灵敏度显著提高,表观摩尔吸光系数ε_(614)=1.40×10~5L·mol^(-1)·cm^(-1)。铑含量在0～0.72μg·ml^(-1)内符合比尔定律。所拟方法操作简便,用于催化剂中微量铑的测定。
A new reagent 2-(3,5-dichloro-2-pyridylazo)-5-dimethylaminoaniline (3,5-diCl-PADMA) is recommended for the determination of rhodium. It is shown that rhodium and 3, 5 -diCl-PADMA form a violetred complex at pH 4.0～5.0. The maximum absorption of the complex is at 614nm in a sulotion of 0.72～6.0 mol/L HCl. Its apparent molar absorptivity is ε_(614)=1.40×10~5L·mol^(-1)·cm^(-1). Beer's law is obeyed in the range of 0～0.72μg Rh·ml^(-1). The method is highly sensitive and selective. Most common ions do not interfere. The mothod has been applied to the determination of trace rhodium in catalysts with satisfactory results.
出处
《贵金属》
CAS
CSCD
北大核心
1993年第4期55-58,共4页
Precious Metals
