Solvent Extraction ICP-MS/MS Method for the Determination of REE Impurities in Ultra-high Purity Ce Chelates

Abstract

This paper describes a new method for the determination of trace rare earth elements (REEs) in cerium chelates of extremely high purity by triple quadruple inductively coupled plasma mass spectrometry (ICP-MS/MS) after solvent extraction. Based on the outstanding performance of ICP-MS/MS, interferences on La, Pr, Tb, Gd, and Yb were reduced by 2~3 orders of magnitude in comparison with ICP-QMS. Further, chemical separation employing solvent extraction using Cyanex 272 (bis(2,4,4-trimethylpentyl) phosphinic acid) was carried out, and about 99.95% of the Ce matrix, after being digested and oxidized to Ce 4+ with KMnO 4 , could be removed, with recoveries for all of the 14 REEs ranging from 92.8% to 103%. Key factors that influenced the separation effects, such as the extraction