PRECISE MEASUREMENT OF ZIRCONIUM ISOTOPES BY THERMAL IONIZATION MASS SPECTROMETRY

Abstract

An analytical method for high-precision measurement of zirconium isotope ratios using a Sector thermal ionization mass spectrometer (TIMS) is reported. The chemical separation procedure of Zr has been refined by employing a small anion exchange resin column to minimize the Mo interference on 92Zr, 94Zr and 96Zr. To confirm the reproducibility of this technique, Zr isotope analyses from six commercially available chemical samples and from two meteorites were carried out. Isotopic ratios were corrected for mass fractionation by normalization with the 94Zr90Zr ratio. The determined ratios 9190, 9290 and 96390 were within the precision range 0.002 to 0.007% (relative standard deviations). The data indicate the existence of zirconium isotopic heterogeneity in the earth and the possibility of pre-terrestrially printed and terrestrially conserved isotope aberration patterns of zirconium is discussed.