Determination of trace amounts of rare earth elements in high-purity cerium oxide by inductively coupled plasma mass spectrometry after separation by solvent extraction

A method was developed For the determination of trace amounts of REEs in high-purity cerium oxide by ICP-MS after separation by solvent extraction, Based on the specificity of 2-ethylhexyl hydrogen-2-ethylhexylphosphonate, the Ce matrix in a tetravalent ionic state was separated from all other trivalent ionic state REEs, After removal of the matrix, the polyatomic interferences in ICP-MS were negligible, More than 99.5% of the Ce matrix was removed with 94-102% recoveries for 14 REE impurities in a spiked sample, The precision was 0.7-2.7% (RSD). The detection limits for 14 rare earth elements were 0.026-0.003 ng cm(-3) in solution and the limits of quantification were 0.02-0.09 mu g g(-1) in solid cerium oxide. The method is rapid, precise and reliable and is well suited for the determination of REE impurities in high-purity cerium oxide.