Routine isotopic analysis of iron by HR-MC-ICPMS: How precise and how accurate?

High-temperature isotopic variations documented in natural materials span a narrow range and call for precise and accurate isotopic analyses. Precisions better than ~ 0.03‰ (95% confidence interval) for δ56Fe have been obtained by High-Resolution Multi-Collector Inductively Coupled Plasma Mass Spectrometry (HR-MC-ICPMS). Whether these uncertainties encompass all sources of error has not been carefully evaluated. The current study examines all parameters that can affect accuracy and precision of Fe isotopic measurements by HR-MC-ICPMS. It is demonstrated that accurate δ56Fe measurements can be routinely achieved within the quoted uncertainties.