PRECISE DETERMINATIONS OF THE ISOTOPIC COMPOSITIONS AND ATOMIC WEIGHTS OF MOLYBDENUM, TELLURIUM, TIN AND TUNGSTEN USING ICP MAGNETIC-SECTOR MULTIPLE COLLECTOR MASS-SPECTROMETRY

Precise determinations of the isotopic compositions of molybdenum, tellurium, tin and tungsten were obtained utilizing an inductively coupled plasma (ICP) source magnetic sector mass spectrometer equipped with multiple collectors. The results of this study are comparable to those measured by conventional and negative thermal ionization mass spectrometry (TIMS and NTIMS) and the values recommended by the International Union of Pure and Applied Chemistry (IUPAC), but with improvement in precision by up to two orders of magnitude. The relative isotopic abundances and atomic weight for each element calculated from the data obtained in this study are also in excellent agreement with previously published values. The only disagreement between this study and IUPAC recommended values is for tellurium. However, with the exception of Te-130, the Te data are in good agreement with those reported in a recent study by De Laeter [1]. The results of this study demonstrate the capability of this new instrument to produce precise and reproducible isotopic data for elements that are difficult to ionize and measure with TIMS. Furthermore, the greater precision of isotopic measurements possible with the ICP source multiple collector magnet sector mass spectrometer greatly enhances the prospects for research on the distribution and isotopic compositions of these elements in terrestrial and meteoritic materials.