【摘要】 本文研究了用2-（5-Br-2-吡啶偶氮）-5-二甲氨基苯胺（简称5-Br-PADMA）吸光光度法测定微量铑的适宜条件。在pH 2.8～6.1范围内,铑与 5-Br-PADMA形成1:3的紫红色配合物。该配合物在1.2mol·L^-1的高氯酸溶液中转变为紫色,其最大吸收峰位于610nm处,表观摩尔吸光系数ε_{6 10}=1.5×10⁵。反应具有良好的选择性,常见金属离子在一定含量范围内无干扰,铑含量为0～0.56μg·ml^-1时,遵守比耳定律。所拟方法操作方便,灵敏度高,用于催化剂中微量铑的测定,获得满意结果。更多还原

【Abstract】 A new reagent 2-（5-bromo-2-Pyridylazo）-5-dimethylamino-aminobenzene （5-Br-PADMA） isRecommended for the determination of rhodium. It is shown that rhodium and 5-Br-PADMA form a violet-red complex at pH 2.8～6.1. The maximum absorbace of the complex is at 610nm in a sulotion of HCIO₄(1.2mol·L^-1). Its apparent molar absorptivity is ε₆₁₀=1.5×10⁵L·mol^-1·cm^-1. Beer’s Law is obeyed within theconcentration range of Rh 0 to 0.56μg·ml^-1. The method is highly sensitive and selective. Most common ionsdid not interfere. The proposed method has been applied to the determination of trace rhodium in catalystsand alloys with satisfactory results.更多还原