铑钨杂多酸-甲苯胺蓝缔合体系测定痕量铑

Determination of Trace Amount of Rhodium with the Rhodium-Tungstate-Toluidine Blue System

研究了在6.0mol/L H2SO4及聚乙烯醇(PVA)存在下,Rh(III)与钨酸盐及甲苯胺蓝(TB)形成缔合物的最佳反应条件,建立了测定Rh(III)的高灵敏光度分析新方法。缔合物体系在570 nm处的吸光度与Rh(III)的在0.01～0.125μg/25 mL质量浓度的吸光度服从比耳定律,其摩尔吸光系ε=5.68×107L·mo l-1·cm-1。大量常见离子对Rh(III)的测定不干扰。建立的方法用于测定催化剂及工业产品中铑的含量,结果与标准方法(SnCl2方法)测得值一致。

The optimum reaction conditions for the formation of an ion-association complex among rhodium, tungstate and toluidine blue （TB） in the presence of poly （vinyl alcohol） （PVA） and in 6.0mol/L H2SO4 medium were studied in this paper. A very sensitive spectrophotometric method for the determination of rhodium was developed based on the reaction. It is suggested experimentally that Beer＇s law is obeyed at 570 nm in the rhodium concentration range of 0.01～0.1251.tg/25 mL.The molar absorptivity（e） is 5.68×107 L.mo1^-1·cm^-1. Many co-exist ions do not interfere with the determination. The results for the determination of rhodium in real samples obtained by this method are consistent with those by SnCl2 method.