Oxygen isotope analysis of phosphates: a comparison of techniques for analysis of Ag3PO4

Détails

ID Serval
serval:BIB_A88FE2AF4E99
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Oxygen isotope analysis of phosphates: a comparison of techniques for analysis of Ag3PO4
Périodique
Chemical Geology
Auteur(s)
Vennemann T.W., Fricke H.C., Blake R.E., O'Neil J.R., Colman A.
ISSN-L
0009-2541
Statut éditorial
Publié
Date de publication
2002
Peer-reviewed
Oui
Volume
185
Pages
321-336
Langue
anglais
Résumé
A comparison has been made of oxygen isotope analyses of natural and
synthetic phosphates using three methods in current use and Ag3PO4 as
the analyte. Of these methods, conventional fluotination using BrF5
provides the most precise and accurate measurements and these analyses
serve as the basis for comparison. Fluorination liberates 100% of the
oxygen in Ag3PO4 and the isotopic composition of this oxygen can be
readily normalized to accepted oxygen isotope ratios of international
reference standards. The widely used method of high-temperature reaction
with graphite in isolated silica tubes is also precise but requires
calibration for scale compression resulting from a combination of
factors including incomplete extraction of oxygen, reaction temperature,
possible oxygen exchange with the silica tube and/or differences in the
grain size of the graphite used. The recently developed method based on
high-temperature carbon reduction and continuous flow mass spectrometric
analysis of CO is relatively fast, requires little sample and provides
100% yields for oxygen. At the present time, this method is less
precise than the other methods examined and requires calibration against
standards on a run to run basis. Five phosphate reference standards with
delta(18)O values ranging from -5.2 parts per thousand to 34.0 parts per
thousand were prepared and packaged for distribution to active workers
in the field. Analyses of these standards will allow normalization and
calibration of results obtained using any available method of oxygen
isotope analysis of phosphate. (C) 2002 Elsevier Science B.V. All rights
reserved.
Création de la notice
29/09/2012 17:23
Dernière modification de la notice
20/08/2019 16:13
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