Combined Separation of Cu,Fe and Zn from Rock Matrices and Improved Analytical Protocols for Stable Isotope Determination |
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| Authors: | Paolo A Sossi Galen P Halverson Oliver Nebel Stephen M Eggins |
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| Affiliation: | 1. Research School of Earth Sciences, Australian National University, Canberra, Australia;2. School of Earth and Environmental Sciences, University of Adelaide, Adelaide, Australia;3. Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montreal, Canada |
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| Abstract: | Isotope ratios of heavy elements vary on the 1/10000 level in high temperature materials, providing a fingerprint of the processes behind their origin. Ensuring that the measured isotope ratio is precise and accurate depends on employing an efficient chemical purification technique and optimised analytical protocols. Exploiting the disparate speciation of Cu, Fe and Zn in HCl and HNO3, an anion exchange chromatography procedure using AG1‐×8 (200–400 mesh) and 0.4 × 7 cm Teflon columns was developed to separate them from each other and matrix elements in felsic rocks, basalts, peridotites and meteorites. It required only one pass through the resin to produce a quantitative and pure isolate, minimising preparation time, reagent consumption and total analytical blanks. A ThermoFinnigan Neptune Plus MC‐ICP‐MS with calibrator‐sample bracketing and an external element spike was used to correct for mass bias. Nickel was the external element in Cu and Fe measurements, while Cu corrected Zn isotopes. These corrections were made assuming that the mass bias for the spike and analyte element was identical, and it is shown that this did not introduce any artificial bias. Measurement reproducibilities were ± 0.03‰, ± 0.04‰ and ± 0.06‰ (2s) for δ57Fe, δ65Cu and δ66Zn, respectively. |
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| Keywords: | non‐traditional stable isotopes Cu Fe Zn isotopes anion exchange chromatography MC‐ICP‐MS mass bias external spike high precision isotopes stables non‐traditionnels isotopes du Cu Fe et Zn chromatographie d'é change d'anions MC‐ICP‐MS biais de masse spike haute pré cision |
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