Determination of rare earth impurities in high purity gadolinium oxide by inductively coupled plasma mass spectrometry after 2-ethylhexylhydrogen-ethylhexy phosphonate extraction chromatographic separation

Abstract

A method was developed for the determination of rare earth impurities in high purity Gd2O3 by inductively coupled plasma mass spectrometry (ICP-MS). The matrix suppression effect of Gd2O3 on signals of rare earth impurities was compensated for by Re internal standardization. The spectra overlap interferences from GdH, GdO, GdOHn (n=1–3) on Tb, Tm, Yb and Lu were eliminated by 2-thylhexylhydrogen-2-ethylhexy phosphonate (EHEHP) extraction chromatographic separation. The detection limits for REEs were 0.005–0.017 ng ml−1 in solution and 0.002–0.05 μg g−1 in solid. Recoveries of spiked sample for REEs were from 88 to 121% with the precision of 1.0–7.5% RSD. Determination of trace REEs in two Gd2O3 samples were performed. The method can be applied to analysis of 99.99–99.9999% high purity Gd2O3.