New isotopic systematics in the Radiogenic and Unconventional Stable Isotopes Laboratory: Fe isotopes
Iron (Fe) isotopes are finding increasingly widespread applications in the Earth sciences, in fields such as cosmogeochemistry, geochemistry and environmental sciences. To ensure increasingly accurate and precise isotopic analyses, it is essential to have well-characterised reference materials. In particular, the direct comparison of data obtained from different laboratories is an essential step in the development of new reliable isotopic systems.
As part of the TEOREM (PRIN-MUR 2017AK8C32) and ITINERIS (IR0000032; PNRR; Next Generation EU) projects, a methodology was developed for determining Fe isotope ratios with high precision using the MC-ICP-MS Neptune Plus mass spectrometer (Thermo Scientific). Specifically, widely used geological reference materials (JB-2, BHVO-2, BE-N, AGV-1 and RGM-1) were analysed, obtaining results consistent with data already published by various laboratories around the world.
In particular, new reference values are proposed for the Fe isotopes of basalt IAEA-B5 (Etna, Italy), already used as an isotopic standard for boron and lithium:
δ⁵⁶Fe = 0.105 ± 0.061 (2σ)
δ⁵⁷Fe = 0.147 ± 0.071 (2σ)
Iron was separated from the matrix using anion exchange chromatography, while mass bias correction was achieved using SSB (standard-sample-standard) bracketing, combined (doping) with the addition of nickel.
In this work, researchers from the Institute of Geosciences and Earth Resources of the National Research Council (CNR) in Pisa recommend the use of the IAEA-B5 standard as a new reference material for analytical validation and quality control in Fe isotope studies. The scientific community can use these values as a basis for future intercalibrations between laboratories.
Reference
Di Giuseppe, P., Vezzoni, S., Iannini Lelarge, S., Rielli, A., Agostini, S. and Dini, A. (2025), Iron Isotope Ratios of IAEA B5 Basalt and Whole-Rock Reference Materials (JB-2, BHVO-2, AGV-1, BE-N and RGM-1) Determined by Multi-Collector Inductively Coupled Plasma-Mass Spectrometry. Geostand Geoanal Res. doi.org/10.1111/ggr.70017
Article available at the link: https://onlinelibrary.wiley.com/doi/pdf/10.1111/ggr.70017
For further information: Paolo Di Giuseppe - paolo.digiuseppe@cnr.it, Simone Vezzoni – simone.vezzoni@cnr.it.
