Determination of the Platinum‐Group Elements and Gold in Twenty Rock Reference Materials by Inductively Coupled Plasma‐Mass Spectrometry (ICP‐MS) after Pre‐Concentration by Nickel Sulfide Fire Assay

Abstract

The platinum‐group elements (PGE) and gold have been determined in twenty international rock reference materials by inductively coupled plasma‐mass spectrometry (ICP‐MS) after pre‐concentration by a nickel sulfide fire assay. It was possible to achieve determination limits for a 50 g sample that ranged from 1 pg g ‐1 (Rh) to 23 pg g ‐1 (Au). Compared to published certified and recommended values for rock reference materials, the trueness of the method was found to be good. However, in some cases we observed large deviations for all elements in the sub 10 ng g ‐1 range within individual reference sample splits. Our results show that the PGE and Au are inhomogeneously distributed in the reference materials analysed here, where they are present in low concentrations, using 50 g test portions.