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 accur ate and precise results for some elements, but not for others. High-re solution glow discharge mass spectrometry (GDMS) offers nearly complet e coverage of the periodic table, thus avoiding the necessity of combi ning results from several techniques to quantitate a wide range of ele ments 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 a nalysis of many important materials, notably the noble metals, is hamp ered somewhat by a lack of standard reference materials. Reliable stan dards can be fabricated in-house, but these lack the necessary trackin g and certification. The analysis of powdered metals provides addition al challenges due to the presence of surface-adsorbed species (H2O, CO 2, etc), occluded atmospheric gases, and the remnants of chemical proc essing. 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 comb ustion (C), ICP-AES (Si, Fe) and quadrupole ICP-MS (Al, Ni, Cu, Zn, Rh , Ag, Cd, Ir, Pt, An and Pb).