Development of High Precision Fe Isotope Measurements with High-Resolution MC-ICPMS Neptune Plus

We report preliminary Iron (Fe) isotopic data of Fe standard solution (IRMM-524B) performed by High Resolution Multi-Collector-Inductively Coupled Plasma-Mass Spectrometer (HR-MC-ICPMS) Neptune Plus in Neptune-TIMS Laboratory (CNR-IGG) and obtained over the past 18 months. Ensuring that the measured isotope ratio is strongly depending to an efficient chemical purification method, and to better separate Fe from matrix, anion exchange chromatography procedure using AG1-X8 (200-400 mesh) and 0.4 x 7 cm Teflon columns was set up to collect Fe. International geological standard materials JB-2 (basalt) and SRM NIST 610 were used with the aim to check the efficiency of chemical separation procedure. The instrumental mass bias was corrected by two independent methods: (i) sample-standard bracketing (SSB), and (ii) Ni doping + SSB. Measurements reveal that high concentration Fe solution standard and Ni doping + SSB has been proved to be a useful method to correct for mass bias fractionation and seems to lead to results quite in agreement with those found in the literature.