Measurement of platinum isotope amount ratios by negative thermal ionization mass spectrometry using a thermionic quadrupole mass spectrometer

A thermal ionization mass spectrometric procedure was developed for the measurement of platinum, Single- and double-filament techniques were investigated. Negative Pt ions 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 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(Pt-194)/n(Pt-195) to be measured with a repeatability of 0.3%.