Determination of δ<sup>44/40</sup>Ca and δ<sup>56/54</sup>Fe in Geological Materials Combined with a Simplified Method for their Separation Using a Single TODGA Resin Column
Qiuyun Guan, Yali Sun, Zhaofeng Zhang, Xiaoming Liu, Yajun An, Fang Liu, Shouqian Zhao
Abstract
A measurement procedure has been developed for the determination of δ 44/40 Ca and δ 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 ± 0.4% ( n = 3) for the former and 99.4 ± 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.