Determination of δ^44/40Ca and δ^56/54Fe in Geological Materials Combined with a Simplified Method for their Separation Using a Single TODGA Resin Column

Abstract

A measurement procedure has been developed for the determination of d 44/40 Ca and d 56/54 Fe in geological samples by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) and thermal ionisation mass spectrometry (TIMS), combined with a single TODGA resin column for their separation. Using the TODGA resin for separation of geological materials, Fe and Ca ions were eluted by using 8 ml of 1.5 mol l-1 HNO 3 and 8 ml of 2 mol l-1 HCl, respectively, and their recovery was 99.7 AE 0.4% (n = 3) for the former and 99.4 AE 0.6% (n = 3) for the latter after removal of matrix and interfering elements using 12 ml of 6 mol l-1 HCl. This procedure was validated by the reference materials AGV-2, BCR-2 and BHVO-2. Their Fe and Ca isotope data were comparable to their literature values, confirming a single column containing TODGA resin can be applied to the separation of Fe and Ca in geological samples for determination of their isotope ratios free of measurement bias.

High-Precision Measurements of 44Ca/40Ca Using Multiple-Collector Inductively Coupled Plasma Mass Spectrometry without Collision-Cell Technology

“…Comparison between previously reported Ca isotopic data and values measured in this study. Previously reported values are from the literature. ,,− ,,− Gray, red, and blue spots represent data from the literature, this study, and average values of literature values. All the compiled data are listed in Table S9.…”