Measurement of Platinum Isotope Amount Ratios by Negative thermal Ionization Mass Spectrometry Using a Thermionic Quadrupole Mass Spectrometer.

A thermal ionisation mass spectrometric procedure was developed for the measurement of platinum. Single and double filament techniques were investigated. Negative Pt ion were produced in the source of a thermionic quadrupole mass spectrometer equipped with a secondary electron multiplier operated in ion counting mode. A high purity platinum aqueous sample solution of natural isotopic composition was used as sample on a rhenium filament. This method allows the natural amount ratio of the major isotopes n(194-Pt)/n(195-Pt) to be measured with a repeatability of 0.3%.JRC.D-Institute for Reference Materials and Measurements (Geel