基于在30～35％的乙醇-水溶液中铑(Ⅲ)与5-Br-PADAP形成1:1的有色配合物,提出了一个有较高灵敏度的吸光光度测定铑的方法。适宜pH的范围是5.0～7.0。铑(Ⅲ)-5-Br-PADAP配合物的摩尔吸光系数ε590=9.0×10~4L·mol~(-1)cm~(-1)方法是有较好的选择性,在抗坏血酸、柠檬酸盐和EDTA存在下适当量的钯、铂、钌、铱、锇及其他许多金属离子不干扰铑的测定。也可根据与5-Br-PADAP反应速度的差异同时测定钯和铑。 Based on a 1: 1 colored complex of rhodium (Ⅲ) with 5-Br-PADAP in 30-35% ethanol-water solution, a method for the determination of rhodium with higher sensitivity by spectrophotometry was proposed. The optimum pH range is 5.0 to 7.0. The molar absorptivity ε590 = 9.0 × 10 ~ 4L · mol -1 cm -1 of rhodium (Ⅲ) -5-Br-PADAP complex is a good selectivity. Ascorbic acid, citric acid Appropriate amounts of palladium, platinum, ruthenium, iridium, osmium and many other metal ions in the presence of salt and EDTA do not interfere with rhodium determination. Palladium and rhodium can also be assayed simultaneously on the basis of the difference in the rate of reaction with 5-Br-PADAP.