丁基罗丹明B-钼酸盐光度法连续测定铈和钪

Spectrophotometric Determination of Cerium and Scandium With Molybdate and Butyl Rhodamine B

在聚乙烯酸（PVA）存在下，丁基罗丹明B（BRB）分别与铈钼、钪钼杂多酸络阴离子形成离子缔合物，其最大吸收均位于570nm，表现摩尔吸光度分别为εCe=3．96×106L·mol－1·cm－1，εSe=4.71×105L·mol－1·cm－1，服从比耳定律范围分别为0～24μg／LCe和0～60μg／LSc，测定极限（空白标准偏差的3倍）为Ce1.0μg／L（n=-12）和Se1.9μg／L（n=10），对于20μg／LCe和4.0μg／LSc测定的RSD分别为4．6％（n=11）和2．0％（n=9）。缔合物的摩尔比为Ce：Mo：BRB=1：6：3，Se：Mo：BRB=1：12：2。本法已用于某些地质样品中铈和钪的连续测定，结果满意。

A spectrophotometric determination of cerium and scandium has been reported.The method is based on .the formation of ion-association complexes of heteropoly molybdo ceric acid or heteropoly molybdoscandic acid with butyl rhodamine B(BRB) in the presence of polyvinyl alcohol (PVA). The absorption maximum is at 570 nm for both cerium and scandi um complexes. The apparent molar absorptivities of ion-association complexes are 3. 96 × 106 L·mol -1·cm-1 for cerium complex and 4. 71 ×105 L·mol-1·cm-1 for scandium complex. Beer' s law is obeyed in the ranges of 0~24 μg/L for cerium and 0~60 μg/L for scandium, the detection limits are 1.0 μg/L for cerium (n= 12) and 1. 9 μg/L for scandium (n= 12) with the relative standard deviation 4. 6% (n =11 ) and 2. 0% (n= 9), respectively.The molar compositions of ion association complexes were found to be Ce: Mo: BRB = 1: 6: 3 and Se: Mo: BRB=1: 12: 2. This method has been applied to the analysis of ge ological samples with satisfactory results.