Reference materials for geochemical PGE analysis: new analytical data for Ru, Rh, Pd, Os, Ir, Pt and Re by isotope dilution ICP-MS in 11 geological reference materials

Abstract

Abundances of Ru, Rh, Pd, Re, Os, Ir and Pt are reported in 11 high- and low-abundance reference materials (RMs) that are currently in use for platinum group element (PGE) analysis. Analytical data was obtained by isotope dilution ICP-MS using a simple on-line chromatographic column for analyte–matrix separation after high-pressure asher (HPA-S) digestion. It is demonstrated that certified concentrations of platinum group element RMs are not sufficiently precise to detect bias. Most provisional and information values of the CANMET-CCRMP RM concentrations below 1 ng g −1 are biased toward higher concentrations. Currently, high-abundance RMs, often with matrices that do not match those of the samples, are used inappropriately for validation of analytical procedures for peridotites and basalts with low to moderate PGE concentrations. To improve this situation, several mafic and ultramafic RMs were included in this study to evaluate their usefulness for geochemical analysis of platinum group elements and rhenium. Peridotites UB-N and GP13 as well as basalt TDB-1 are sufficiently homogeneous at a 2-g test sample portions level to be used as RMs for method validation.