Determination of platinum-group elements in OPY-1: Comparison of results using different digestion techniques

Abstract

A new proficiency testing sample, OPY-1 (ultramafic rock), the basis of the twentieth international proficiency test of analytical geochemistry laboratories (Geo PT 20), was recently prepared by the International Association of Geoanalysts (IAG). This paper reports analytical data for Os, Ir, Ru, Rh, Pt and Pd with different digestion techniques, including an improved Carius tube, Carius tube combined with HF dissolution and alkaline fusion. About 4-15% of the PGEs are in the silicate phase, which cannot be leached by aqua regia even when digested at 300 °C with the Carius tube technique. Both the Carius tube technique combined with HF dissolution and alkaline fusion can obtain reliable data. The results demonstrated that OPY-1 is sufficiently homogeneous at a 2 g test portion level to be suitable as a reference material for method validation. The procedure for sealing the Carius tube was simplified and the recommended digestion procedures are provided. © 2008 The Authors. Journal compilation © 2008 International Association of Geoanalysts.