High-precision cadmium stable isotope measurements by double spike thermal ionisation mass spectrometry

Schmitt, Anne‐Désirée; Galer, S. J. G.; Abouchami, W.

doi:10.1039/b821576f

Cited by 95 publications

(110 citation statements)

References 51 publications

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“…Sample preparation for isotope dilution-thermal ionization mass spectrometry (ID-TIMS) measurements of dissolved Cd involved further acidification to pH 5 1 (HCl, Baseline Seastar TM ) and subsequent Cd extraction on an ion exchange column following established protocols (Schmitt et al 2009;Abouchami et al 2011). This method, initially developed for simultaneous determination of Cd concentration and Cd isotope composition in seawater, was slightly modified to allow faster processing of smaller volumes (10 mL) for concentration data only.…”

Section: Methodsmentioning

confidence: 99%

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Baars¹,

Abouchami²,

Galer³

et al. 2014

Limnology & Oceanography

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109

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We report isotope dilution analyses of dissolved cadmium (Cd) and electrochemical Cd speciation measurements in the Atlantic sector of the Southern Ocean. Bioavailable inorganic Cd is . 100 times higher in nearsurface waters south of the Polar Front compared to the Subantarctic Zone because of upwelling and reduced complexation by organic Cd ligands. To trace local changes in the relation between Cd and P, we examine the deviations from a linear deep-water Cd vs. P relation (Cd*), and find that changes in Cd* coincide with the position of frontal systems and covary with primary productivity and total dissolved Mn and Fe concentrations. These covariations agree with potential local changes in phytoplankton Cd uptake rates, resulting from differences in the availability of Cd, Zn, Mn, and Fe. A band of negative Cd* values is associated with formation of Subantarctic Mode Water (SAMW) and Antarctic Intermediate Water (AAIW). In contrast to SAMW, which may export low Cd : P ratios from the Southern Ocean, the Cd : P ratios in AAIW increase by mixing with underlying Upper Circumpolar Deep Water before being exported from the Southern Ocean. Deep waters show constant Cd : P ratios, and both elements behave conservatively with end-member mixing between deep waters of the Weddell Gyre, the Antarctic Circumpolar Current, and inflowing North Atlantic Deep Water. Overall, our results support the hypothesis that the kink in the global Cd vs. P relation is largely caused by high Cd : P uptake ratios in the trace-nutrient-limited Southern Ocean.

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Section: Methodsmentioning

confidence: 99%

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Baars¹,

Abouchami²,

Galer³

et al. 2014

Limnology & Oceanography

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109

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“…Following analysis, data were reduced offline at the cycle level based on the iterative methods reported in Siebert et al (2001) (Rosman et al 1980) for internal normalization purposes. Further details regarding methods and choice of double spike can be found in Schmitt et al (2009). Samples were weighed and spiked with an optimal amount of double spike and left to equilibrate for 24 h. A first batch of samples was processed in collaboration with the Bristol group using an aluminum hydroxide coprecipitation method in an attempt to extract simultaneously Cd and Zn, followed by column chromatographic separation of Cd and Zn.…”

Section: Imperial College Cadmium Isotope Methodsmentioning

confidence: 99%

“…The secondary "clean-up" columns are home-made from 3/8 inch diameter 4:1 shrink-fit PFA, and filled with anion exchange resin (100 µL AG1-¥ 8 resin, 100-200 mesh). The Cd fraction was purified using HNO 3 -HBr mixtures, as has been described elsewhere (Schmitt et al, 2009). Blanks are around 15 pg cadmium for the entire procedure.…”

Section: Imperial College Cadmium Isotope Methodsmentioning

confidence: 99%

GEOTRACES IC1 (BATS) contamination‐prone trace element isotopes Cd, Fe, Pb, Zn, Cu, and Mo intercalibration

Boyle

John

Abouchami

et al. 2012

Limnology & Ocean Methods

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107

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The stable isotope composition of radiogenic and natural elements provides a powerful tool for unraveling element sources and biogeochemical processes in the marine environment. Depending on the element, trace element isotope ratios can (1) narrow possible sources of the element in a sample and/or (given a temporal history boundary condition) constrain the time the when the element departed the ocean surface (e.g., Pb, Nd), (2) provide information on redox processes that the element is directly or indirectly involved in (e.g., Fe, Mo, Tl), (3) indicate the extent of biological uptake and/or ocean mixing of the element (e.g., Cd, Zn).However, these trace metals occur at picomolar to nanomolar concentrations, and precise stable isotope measurements require 100-1000 times more sample than required for concentration determination. AbstractWe report data on the isotopic composition of cadmium, copper, iron, lead, zinc, and molybdenum at the GEOTRACES IC1 BATS Atlantic intercalibration station. In general, the between lab and within-lab precisions are adequate to resolve global gradients and vertical gradients at this station for Cd, Fe, Pb, and Zn. Cd and Zn isotopes show clear variations in the upper water column and more subtle variations in the deep water; these variations are attributable, in part, to progressive mass fractionation of isotopes by Rayleigh distillation from biogenic uptake and/or adsorption. Fe isotope variability is attributed to heavier crustal dust and hydrothermal sources and light Fe from reducing sediments. Pb isotope variability results from temporal changes in anthropogenic source isotopic compositions and the relative contributions of U.S. and European Pb sources. Cu and Mo isotope variability is more subtle and close to analytical precision. Although the present situation is adequate for proceeding with GEOTRACES, it should be possible to improve the within-lab and between-lab precisions for some of these properties.

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“…Unfortunately, the base material is isotopically fractionated relative to the mean Earth's crust by −1.3 ‰ [264,269]; therefore, the scientific community is searching for a new zero-delta material. In the meantime, this criterion has been achieved with NIST SRM 3108 [263].…”

Section: Cadmiummentioning

confidence: 99%

Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report)

Brand

Coplen

Vogl

et al. 2014

Pure and Applied Chemistry

565

436

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Abstract:Since the early 1950s, the number of international measurement standards for anchoring stable isotope delta scales has mushroomed from 3 to more than 30, expanding to more than 25 chemical elements. With the development of new instrumentation, along with new and improved measurement procedures for studying naturally occurring isotopic abundance variations in natural and technical samples, the number of internationally distributed, secondary isotopic reference materials with a specified delta value has blossomed in the last six decades to more than 150 materials. More than half of these isotopic reference materials were produced for isotope-delta measurements of seven elements: H, Li, B, C, N, O, and S. The number of isotopic reference materials for other, heavier elements has grown considerably over the last decade. Nevertheless, even primary international measurement standards for isotope-delta measurements are still needed for some elements, including Mg, Fe, Te, Sb, Mo, and Ge. It is recommended that authors publish the delta values of internationally distributed, secondary isotopic reference materials that were used for anchoring their measurement results to the respective primary stable isotope scale.

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High-precision cadmium stable isotope measurements by double spike thermal ionisation mass spectrometry

Cited by 95 publications

References 51 publications

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

Dissolved cadmium in the Southern Ocean: Distribution, speciation, and relation to phosphate

GEOTRACES IC1 (BATS) contamination‐prone trace element isotopes Cd, Fe, Pb, Zn, Cu, and Mo intercalibration

Assessment of international reference materials for isotope-ratio analysis (IUPAC Technical Report)

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