Neutron activation analysis for osmium and ruthenium in platinum

Abstract

The chemical behavior of platinum in its compounds may be influenced by trace impurities. Determination of the identity and quantity of possible impurities in platinum furnished the motivation for this investigation. Platinum is commonly found in the native form associated with the other noble metals; osmium, ruthenium, rhodium, iridium, palladium, silver and gold. The first five with platinum constitute the heavier group VIII members, usually called the platinum group. Due to their closely similar chemical behavior, the other noble metals often remain as trace impurities in refined platinum. Even in carefully purified laboratory platinum stock, three of the noble metals have been found (1). The thermal-neutron activation analysis procedure indicated the following impurity levels; 15+2 ppb Ir, 28+4 ppb Pd and 2.4 + .3 ppra Ag. This investigation extends the above work to include osmium and lathenium, which were expected to occur at similar or even lower levels. Such concentrations exclude the use of most conventional methods of quantitative analysis. Both osmium and ruthenium have potential (n,Y) produced iso topes (2) amenable to multichannel gamma-ray scintillation spectrometry. The sensitivity and selectivity of neutron