Determination of Sc, Y and Rare Earth Elements in Geochemical Samples by High Resolution Inductively Coupled Plasma-Mass Spectrometry

An analytical method for the determination of Sc, Y and 14 rare earth elements (La, Ce, P, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) by high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS) has been developed. Samples were decomposed by HF-HNO₃-H₂SO₄-aqua regia, then 16 elements above in the solution were directly analyzed by HR-ICP-MS. The spectra interferences from polyatomic ions and oxide ions (MO⁺) could be avoided by measuring at high resolution mode. The optimal determination isotopes and appropriate resolution for rare earth elements (REEs) were selected. The operating parameters of HR-ICP-MS were optimized by testing geochemical standard materials with plenty of matrix. The detection limits (6σ) of the method for REEs were 0.003~0.013 μg/g (DF=1000). The relative standard deviation (RSD) was less than 6% (n=12). The method has been applied to determination of Sc, Y and REEs in geochemical national standard reference materials and the analytical results were in agreement with the certified values.