SIMULTANEOUS DETERMINATION OF TRACE ELEMENTS IN PLATINUM BY ISOTOPE DILUTION AND SPARK SOURCE MASS SPECTROMETRY

An isotope dilution technique using the spark source mass spectrograph was investigated for applicability to simultaneous multi-element trace determinations. Isotopically altered Ag, Cu, Ni, Pb, and Pd were separated from a 250-mg sample of platinum by cation exchange, and electrodeposited onto gold electrodes for sparking in the spectrograph. Electrodeposition provided the spiked analytes in an adherent form, relatively free of anions and organic residue from the ion exchange resins, both of which could complicate the spectrum. Contamination, the principal limitation of the method, was minimized by isothermally distilling the reagent acids and by isolating the operations from the laboratory environment. After determining the isotope ratios, the concentrations were computed, ranging from 0.5 ppm (μg/gram) for Ni to 14 ppm for Pb. Improved precision and accuracy was obtained compared to conventional spark source analysis. The results were compared with those of other methods and the platinum material was issued by NBS as Standard Reference Material 681. © 1969, American Chemical Society. All rights reserved.