A Reflection on Mg, Cd, Ca, Li and Si Isotopic Measurements and Related Reference Materials |
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Authors: | Jean Carignan Damien Cardinal Anton Eisenhauer Albert Galy Mark Rehkamper Frank Wombacher Nathalie Vigier |
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Institution: | CNRS-CRPG, 15, rue Notre-Dame cles Pauvres, BP 20, 54501 Vandoeuvre-les-Nancy, France;Department of Geology, Section of Petrology and Mineralogy, Royal Museum for Central Africa, Tervuren 3080, Belgium;GEOMAR, Forschungszentrum für Marine Geowissenschaften, Wischhofstrasse 1–3, D-24148 Kiel, Germany;Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, UK, CB2 2EQ;Institute of Isotope Geology and Mineral Resources, ETH-Zentrum, CH-8092 Zürich, Switzerland;Institute für Mineralogie, Universitãt Münster, Corrensstrasse 24, 48149 Germany |
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Abstract: | This contribution aims to report the reflections we had with the scientific community during two international workshops on reference materials for stable isotopes in Davos (2002) and Nice (2003). After evaluating the isotopic homogeneity of some existing reference materials, based on either certificates, literature data or specific inter-laboratory rounds, we confirm these as primary reference materials or propose new ones relative to which stable isotope compositions should be reported. We propose DSM-3 for Mg, NIST SRM 915a for Ca, L-SVEC for Li and NBS28 for Si. Cadmium does not yet have a well identified delta zero material, although three commercial mono-elemental Cd solutions have yielded the same isotopic composition relative to one another. In order to scale the linearity of any mass spectrometer, some secondary reference materials are also proposed: Cambridge-1 solution for Mg, the "Münster-Cd" and JEPPIM Cd solutions for Cd and the "Big Batch" silicate for Si. The team from Nancy propose to prepare a mixed spike solution for Li isotopes. Well-characterised natural samples such as ocean or continental waters, diatoms, sponges, rocks and minerals are needed to validate the entire analytical procedure, particularly to take into account the effect of sample mineralisation and of chemical manipulations for elemental separation prior to analysis. |
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Keywords: | Keywords: reference materials stable isotopes MC-ICP-MS magnesium calcium cadmium lithium silicon |
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