A new method for the separation of LREEs in geological materials using a single TODGA resin column and its application to the determination of Nd isotope compositions by MC-ICPMS

Abstract

A new method was developed for the purification of Nd in geological samples using a single column containing TODGA extraction resin and the precise determination of Nd isotope ratios by multicollector inductively coupled plasma-mass spectrometry (MC-ICPMS). The samples were digested with HF–HNO₃ and then transferred to a solution of 3 M HNO₃. After loading the solutions onto the TODGA resin column, the column was first eluted with 12 ml of 2.3 M HCl, followed by 8 ml of 1.2 M HCl. The Nd isotope ratios of the latter eluate were measured by MC-ICPMS. This separation procedure was validated by measuring the ¹⁴³Nd/¹⁴⁴Nd ratios (mean ± 2σ) of certified reference materials, BHVO-2, BCR-2 and AGV-2, which were determined to be 0.512989 ± 0.000012, 0.512635 ± 0.000012 and 0.512790 ± 0.000018, respectively, in good agreement with the certified and literature values.