Determination of Rare Earth Elements, Zirconium, Hafnium, Thorium and Uranium in Ultramafic Rocks by ICP-MS after RE-UTEVA Resin Columns for Separation and Pre-Concentration

Abstract

A simple method was developed for the determination of REEs, Zr, Hf, Th and U in ultramafic rocks by inductively coupled plasma-mass spectrometry with a combination of RE and UTEVA extraction resins for their separation and pre-concentration. Ultramafic rocks were digested with HNO₃-HF-HClO₄ and finally turned into 11 mol l⁻¹ HCl solutions together with H₃BO₃ to remove insoluble fluorides. The removal of matrix elements was achieved during the loading procedure. Following this, REEs on RE resin, and Zr, Hf, Th and U on UTEVA resin were eluted with 10 ml of 0.24 mol l⁻¹ HCl, with recoveries better than 94.4%. This method was validated using reference materials JP-1, DTS-2B, OKUM, UB-N, MUH-1 and DZΣ-2, and the measurement results for target analytes were comparable to literature values, indicating its applicability to the determination of REEs, Zr, Hf, Th and U at ultra-trace level in ultramafic rocks.