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

摘要

A method was developed for the determination of rare earth impurities in high purity Gd_2O_3 by inductively coupled plasma mass spectrometry (ICP-MS). The matrix suppression effect of Gd_2O_3 on signals of rare earth impurities was compensated for by Re internal standardization. The spectra overlap interferences from GdH, GdO, GdOH_n (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 #mu#g 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 Gd_2O_3 samples were performed. The method can be applied to analysis of 99.99-99.9999% high purity Gd_2O_3.