Selenium, iron, and chromium stable isotope ratio measurements by the double isotope spike TIMS method

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Abstract

This chapter focuses on the double-spike calibrated thermal ionization mass spectrometry (TIMS) methods for measurement of mass dependent isotope fractionation in Se, Fe, and Cr. Current measurement precision is approximately ± 0.2 per mil on 80Se / 76Se, 56Fe / 54Fe, and 53Cr / 52Cr. Sample size requirements are 500ng, 1μg, and 250ng for Se, Fe, and Cr respectively. These measurements have been developed recently, and further improvements in precision and sample size are likely. The present purification procedures for these elements and the geochemical applications of the measurements are reviewed. TIMS instruments were usually limited to measurement of positive ions. One of the major recent developments in TIMS is the development of methods for measuring negative ions. An important future direction in mass spectrometry of Se, Fe, and Cr, is multi-collector inductively coupled plasma- mass spectrometry (MC-ICP-MS). This recent technique has a number of advantages over TIMS techniques and may eventually dominate. Instrumental discrimination is very large with MC-ICP-MS and must be monitored and modeled correctly.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Selenium, iron, and chromium stable isotope ratio measurements by the double isotope spike TIMS method
Chapter 29
DOI 10.1016/B978-044451114-0/50031-4
Volume 1
Year Published 2004
Language English
Publisher Elsevier
Contributing office(s) National Research Program - Western Branch, Toxic Substances Hydrology Program
Description 44 p.
Larger Work Type Book
Larger Work Title Handbook of stable isotope analytical techniques
First page 623
Last page 651