Analysis of trace impurities in palladium metal powders by glow discharge mass spectrometry

Metals are often analysed for trace impurities using a combination of techniques (i.e., ICP-MS, ICP-AES, combustion, etc.) which offer accurate and precise results for some elements, but not for others. High-resolution glow discharge mass spectrometry (GDMS) offers nearly complete coverage of the periodic table, thus avoiding the necessity of combining results from several techniques to quantitate a wide range of elements in a single sample. GDMS is a direct solids analytical technique, which provides an additional advantage as samples do not have to be dissolved prior to analysis. However, the application of GDMS to the analysis of many important materials, notably the noble metals, is hampered somewhat by a lack of standard reference materials. Reliable standards can be fabricated in-house, but these lack the necessary tracking and certification. The analysis of powdered metals provides additional challenges due to the presence of surface-adsorbed species (H2O, CO2, etc), occluded atmospheric gases, and the remnants of chemical processing. However, GDMS analysis of Pd powders for a wide range of trace impurities (C, Al, Si, Fe, Ni, Co, Zn, Rh, Ag, Cd, Ir, Pt, Au and Pb) provided comparable results to analyses of the same materials by combustion (C), ICP-AES (Si, Fe) and quadrupole ICP-MS (Al, Ni, Cu, Zn, Rh, Ag, Cd, Ir, Pt, An and Pb).