A fully automated simultaneous single-stage separation of Sr, Pb, and Nd using DGA Resin for the isotopic analysis of marine sediments

Abstract

A novel, fast and reliable sample preparation procedure for the simultaneous separation of Sr, Pb, and Nd has been developed for subsequent isotope ratio analysis of sediment digests. The method applying a fully automated, low-pressure chromatographic system separates all three analytes in a single-stage extraction step using self-packed columns filled with DGA Resin. The fully automated set-up allows the unattended processing of three isotopic systems from one sediment digest every 2 h, offering high sample throughput of up to 12 samples per day and reducing substantially laboratory manpower as compared to conventional manual methods. The developed separation method was validated using the marine sediment GBW-07313 as matrix-matched certified reference material and combines quantitative recoveries (>90% for Sr, >93% for Pb, and >91% for Nd) with low procedural blank levels following the sample separation (0.07 μg L Sr, 0.03 μg L Pb, and 0.57 μg L Nd). The average δ values for Sr, Pb, and Nd of the separated reference standards were within the certified ranges (δ (Sr/Sr) of -0.05(28) ‰, δ(Pb/Pb) of -0.21(14) ‰, and δ(Nd/Nd) of 0.00(7) ‰). The DGA Resin proved to be reusable for the separation of >10 sediment digests with no significant carry-over or memory effects, as well as no significant on-column fractionation of Sr, Pb, and Nd isotope ratios. Additional spike experiments of NIST SRM 987 with Pb, NIST SRM 981 with Sr, and JNdi-1 with Ce revealed no significant impact on the measured isotopic ratios, caused by potential small analyte peak overlaps during the separation of Sr and Pb, as well as Ce and Nd.

First Multi‐Isotopic (Pb‐Nd‐Sr‐Zn‐Cu‐Fe) Characterisation of Dust Reference Materials (ATD and BCR‐723): A Multi‐Column Chromatographic Method Optimised to Trace Mineral and Anthropogenic Dust Sources

“…The 202 Hg beam intensity, consistently below 0.15 mV, was monitored to correct for these very low isobaric interferences of 204 Hg on 204 Pb. This correction was performed online applying equations detailed in Retzmann et al (2017) (Chauvel and Blichert-Toft 2001) were diluted to a concentration of 200 ng ml -1 Nd reaching~3 V on the 144 Nd mass. The analyses were performed in wet mode, but sample solutions as low as 10 ng ml -1 can also be measured using a dry plasma mode (Aridus, CETAC Technologies, Omaha, NE, USA).…”

Automation of boron chromatographic purification for δ11B analysis of coral aragonite

“…Here we present a new protocol that facilitates this step through the automation of boron purification using the prepFAST‐MC (prepFAST Multi Collector, developed by Elemental Scientific, ESI, Omaha, NE, USA). This method has been used successfully for other isotopic systems measured in various materials, including Sr and Ca isotopes, 19 Cu isotopes in biological samples, 20 separation of Sr, Pb and Nd isotopes from marine sediments, 21 U and Th isotopes in corals, 22 and Nd 23 . Here for boron isotopes, we optimise the blank contribution and matrix wash‐out and test the method on a variety of standards and matrices including coral samples, seawater, and carbonate/boric acid reference materials or standards.…”

“…Here for boron isotopes, we optimise the blank contribution and matrix wash‐out and test the method on a variety of standards and matrices including coral samples, seawater, and carbonate/boric acid reference materials or standards. The reader is referred to the literature 19,21,22 and Figure S1 (supporting information) for a more complete description of the prepFAST‐MC system and schematic of the set‐up used here.…”

Determination of δ44/40Ca and δ56/54Fe in Geological Materials Combined with a Simplified Method for their Separation Using a Single TODGA Resin Column

“…Therefore, it is definitely a simple and time-saving method for purification of both Ca and Fe using only one column containing TODGA resin and facilitates determination of their isotope ratios in geological materials. So far, TODGA resin has proved to be sufficient to remove interfering ions from geological samples and successful measurements have been achieved for non-traditional Fe-Ca isotopes and traditional Sr-Nd-Hf-Pb isotopes (Connelly et al 2006, Pourmand and Dauphas 2010, Li et al 2016, Feng et al 2017, Retzmann et al 2017, Guan et al 2019. With combination of the non-traditional and traditional isotopes, it is very useful to widen the applicability of the TODGA resin to geological samples for the determinations of multi-elemental isotopes, particularly for precious and rare samples with less sample size, such as meteorites.…”