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Kaiser, Jan 
ORCID: https://orcid.org/0000-0002-1553-4043 and Röckmann, Thomas
(2008)
Correction of mass spectrometric isotope ratio measurements for isobaric isotopologues of O2, CO, CO2, N2O and SO2.
Rapid Communications in Mass Spectrometry, 22 (24).
pp. 3997-4008.
ISSN 1097-0231
Abstract
Gas isotope ratio mass spectrometers usually measure ion current ratios of molecules, not atoms. Often several isotopologues contribute to an ion current at a particular mass-to-charge ratio (m/z). Therefore, corrections have to be applied to derive the desired isotope ratios. These corrections are usually formulated in terms of isotope ratios (R), but this does not reflect the practice of measuring the ion current ratios of the sample relative to those of a reference material. Correspondingly, the relative ion current ratio differences (expressed as d values) are first converted into isotopologue ratios, then into isotope ratios and finally back into elemental d values. Here, we present a reformulation of this data reduction procedure entirely in terms of d values and the ‘absolute’ isotope ratios of the reference material. This also shows that not the absolute isotope ratios of the reference material themselves, but only product and ratio combinations of them, are required for the data reduction. These combinations can be and, for carbon and oxygen have been, measured by conventional isotope ratio mass spectrometers. The frequently implied use of absolute isotope ratios measured by specially calibrated instruments is actually unnecessary. Following related work on CO2, we here derive data reduction equations for the species O2, CO, N2O and SO2. We also suggest experiments to measure the required absolute ratio combinations for N2O, SO2 and O2. As a prelude, we summarise historic and recent measurements of absolute isotope ratios in international isotope reference materials.
| Item Type: | Article |
|---|---|
| Faculty \ School: | Faculty of Science > School of Environmental Sciences University of East Anglia Research Groups/Centres > Theme - ClimateUEA |
| UEA Research Groups: | Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences Faculty of Science > Research Groups > Marine and Atmospheric Sciences (former - to 2017) Faculty of Science > Research Groups > Atmospheric Chemistry (former - to 2018) Faculty of Science > Research Groups > Climate, Ocean and Atmospheric Sciences (former - to 2017) |
| Depositing User: | Rosie Cullington |
| Date Deposited: | 25 Feb 2011 12:14 |
| Last Modified: | 03 Jan 2024 01:59 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/24655 |
| DOI: | 10.1002/rcm.3821 |
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