Correction of instrumentally produced mass fractionation during isotopic analysis of Fe by thermal ionization mass spectrometry

  • Johnson C
  • Beard B
  • 70

    Readers

    Mendeley users who have this article in their library.
  • 116

    Citations

    Citations of this article.

Abstract

High-precision (~0.015%/mass) isotope ratio measurements of Fe may be obtained by using magnetic-sector thermal ionization mass spectrometry (TIMS), where rigorous correction of instrumentally produced mass fractionation can be made. Such corrections are best done by using a double-spike approach, which was first introduced several decades ago. However, previous derivations do not lend themselves to the high-precision isotope analysis that modern TIMS instruments are capable of because of various assumptions of mass fractionation laws or constant atomic weights. Moreover, some of these previous approaches took iterative approaches to the calculation, and none presented detailed error propagations. Here we present a completely general derivation to the double-spike a approach that may be used for any appropriate isotope system and is applicable to the mass fractionation laws that are known to occur in TIMS. In addition, we present an assessment of error propagation as a function of algorithm and spike isotope composition. This approach has produced the highest precision Fe isotope ratio measurements yet reported, on the older of ±0.2 to 0.3 per mil for the54Fe/56Fe ratio, that correct for instrumentally produced mass fractionation and yet retain natural, mass-dependent isotopic variations in samples. (C) 1999 Elsevier Science B.V.

Author-supplied keywords

  • Double spike
  • Fe
  • Isotope
  • Mass spectrometry
  • Thermal ionization

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Get full text

Authors

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free