二溴羟基苯基荧光酮－溴化十六烷基三甲铵分光光度法测定微量铑

Spectrophotometric Determination ofMicroamounts of Rhodium with 2,6,7-Tri-hydroxy-9-( 3,5-Dibromo-4-Hydroxy) Phen-ylfluorone and CetyItrimethylamlnoniumBromide

本文提出了分光光度测定铑的新方法。在ｐＨ＝５．８～６．７的磷酸盐缓冲介质中，铑与二溴羟基苯基荧光酮－溴化十六烷基三甲铵反应生成的配合物最大吸收峰位于６１０ｎｍ，对比度为８０ｎｍ，表观摩尔吸光系数为１．２９×１０￣５Ｌ·ｍｏｌ￣（－１）·ｃｍ￣（－１）。铑浓度在０～５．０μｇ／１０ｍＬ范围内符合比尔定律。经离子交换分离消除贱金属等的干扰后，可用于二次合金中微量铑的测定，结果满意。

A new spectrophotometric method fordetermination of microamounts ofrhodiumhas been proposed,In phosphate medium atpH 5.8～6.7,rhodium reacts with 2,6,7-tri-hydroxy-9-(3,5-dibromo-4-hydroxy)pheny-lfluorone(DBHPF) and cetyItrimethylamm-onium bromide to develop a stable , solublecomplex, The comple has a maximum ab-sorption at 610nm,and its apparent molarabsorptivity is 1.29 ×10￣5L·mol￣(-1)·cm￣(-1)。The molar ratio of rhodium(Ⅲ)to DBHPFin the complex is estimated to be 1: 3. Beer’s law is obeyed in the range of 0～5.0μg/10mL rhodium. Most of common metal ionsare separated by ion-exchange technique.The method has been applied to the determi-nation of rhodium in a secondary alloy andthe analytical results correspond with thatobtained by a polarographic method.