Testing miniaturized extraction chromatography protocols for combined <scp><sup>87</sup>Sr</scp>/<scp><sup>86</sup>Sr</scp> and <i>δ</i><sup>88/</sup><scp><sup>86</sup>Sr</scp> analyses of pore water by <scp>MC‐ICP‐MS</scp>
Claudio Argentino, Federico Lugli, Anna Cipriani, Giuliana Panieri
Abstract
Abstract We tested two miniaturized extraction chromatography protocols for strontium isolation based on 300 μ L (Protocol 1) and 30 μ L (Protocol 2) column volumes of Sr‐Spec resin, for the simultaneous determination of 87 Sr/ 86 Sr and δ 88/86 Sr by MC‐ICP‐MS. The accuracy and precision of the Sr isotope ratios have been evaluated by analyzing JCt‐1 and SRM 1640a reference materials, resulting in a reproducibility of 87 Sr/ 86 Sr and δ 88/86 Sr values of 0.000026 and 0.04‰ (Protocol 1) (2SD, n = 3), and of 0.000074 and 0.13‰ (Protocol 2) (2SD, n = 4), respectively. The Sr isotopic composition of SRM 1640a, presented here for the first time, is 87 Sr/ 86 Sr = 0.708790 ± 0.000062 and δ 88/86 Sr = 0.07 ± 0.10‰ (2SD, n = 6). Protocols 1 and 2 were successfully applied to pore waters extracted from marine sediment cores from the northern Barents Sea. Our results demonstrate that both protocols attain accurate 87 Sr/ 86 Sr ratios and allow the detection of natural variations in δ 88/86 Sr in marine pore waters. Compared to previous Sr/matrix separation methods, Protocol 2 is significantly less costly, making it particularly suitable for large‐scale oceanological and limnological studies.