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Quantitative Imaging of Stable Isotopes by Ion Microprobe
Author(s) -
Aléon Jérôme,
Chaussidon Marc,
Champenois Michel,
Mangin Denis
Publication year - 2001
Publication title -
geostandards newsletter
Language(s) - English
Resource type - Journals
eISSN - 1751-908X
pISSN - 0150-5505
DOI - 10.1111/j.1751-908x.2001.tb00998.x
Subject(s) - microprobe , analyser , analytical chemistry (journal) , microbeam , ion , stable isotope ratio , materials science , isotopes of oxygen , secondary ion mass spectrometry , chemistry , mass spectrometry , optics , mineralogy , chromatography , physics , nuclear chemistry , nuclear physics , organic chemistry
A new analytical procedure has been developed to measure oxygen isotopic ratios and, more generally, stable isotopic ratios in microparticles with a few % precision. This procedure uses ion microprobe quantitative imaging with a scanning microbeam. In this mode, ion images are acquired on the electron multiplier. Image processing allows extraction of areas of interest from the whole image and computation of isotopic ratios in the selected areas. The accuracy of this method has been tested for the analysis of the 18O/16O ratio in quartz and magnetite reference samples powdered to a grain size of 2‐5 μm. A detailed study of the instrumental mass fractionation allowed an understanding of differences between classical spot analysis and scanning ion imaging, and showed that fractionation effects were related to grain topography for microparticle analysis, and to image processing or to secondary optical settings for ion imaging. The precision obtained for the measurement of ä18O was 3% for grains having a diameter of 2 μm.