Platinum-group element geochemical certified reference materials (GPt1-7)

Unlike the situation for other elements, few reference materials certified for the platinum-group elements are currently available. Therefore, the GPt 1-7 series of PGE geochemical CRMs, prepared by the IGGE, represent on impo rtant addition and comprise a range of matrix types, including a soil, stre am sediment, Mg-rich ultramafic rock. Fe-rich ultramafic rock, platinoid or e depleted in Cu, Ni and Fe, and a chromitite. The concentration of PGE in these samples ranges over 4-5 orders of magnitude and the samples were show n to have good homogeneity as assessed by a variance test. Analytical metho ds based on different principles were used in sample certification, includi ng several fire assay and wet chemical procedures used for decomposition an d preconcentration. Certified values for the elements Pt, Pd, Os, Ru, Ir, R h and Au were determined by AAS, catalytic colourimetry (COL), catalytic po larography (POL), atomic emission spectrometry (AES), ICP-MS and NAA. Recen tly, the GPt1-7 samples were approved as national primary CRMs by the State Bureau of Technical Supervision of China.