Testing miniaturized extraction chromatography protocols for combined 87Sr/86Sr and δ88/86Sr analyses of pore water by MC-ICP-MS

• Published in: Limnology and Oceanography: Methods
• Main Authors: Argentino C., Lugli F., Cipriani A., Panieri G.
• Other Authors: Argentino, C., Lugli, F., Cipriani, A., Panieri, G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Barents Sea
• Online Access: http://hdl.handle.net/11380/1268806; https://doi.org/10.1002/lom3.10435

We tested two miniaturized extraction chromatography protocols for strontium isolation based on 300 μL (Protocol 1) and 30 μL (Protocol 2) column volumes of Sr-Spec resin, for the simultaneous determination of 87Sr/86Sr and δ88/86Sr 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 87Sr/86Sr and δ88/86Sr 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 87Sr/86Sr=0.708790 ± 0.000062 and δ88/86Sr=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 87Sr/86Sr ratios and allow the detection of natural variations in δ88/86Sr 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.