Measuring 0.01‰ to 0.1‰ isotopic variations by MC-ICPMS - Testing limits for the first time with Pb δ-iCRMs

Abstract

A blind comparison on Pb-isotope δ-scale measurements by MC-ICPMS of 0.01‰ to 0.1‰ level was organised, involving five laboratories. Test samples were obtained from the series of candidate ERM-3810 δ-isotopic Certified Reference Materials (δ-iCRMs), and comprise four pairs of a material with ∼natural Pb-isotopic composition ('delta zero' or 'δ-0') and the same natural Pb progressively enriched in 207Pb (with δ207Pb values certified to ∼0.1% relative uncertainty, k = 2). Participants were free to apply the measurement strategy of their choice. A result was considered 'acceptable' only when, simultaneously, there was agreement within stated uncertainties with the corresponding reference value ..