Relative isotope-ratio difference: Difference between revisions
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::δ = (R<sub>sample</sub> R<sub>standard</sub>)/R<sub>standard</sub> where R is the isotope ratio of the element. | ::δ = (R<sub>sample</sub> R<sub>standard</sub>)/R<sub>standard</sub> where R is the isotope ratio of the element. | ||
:''Note 1'': The reference is often an international measurement standard. | :''Note 1'': The reference is often an international measurement standard. | ||
:''Note 2'': The same relative differences are used to calculate delta values from the abundance of isotopomers and isotopologs, ion currents, frequencies, or optical extinctions. | :''Note 2'': The same relative differences are used to calculate delta values from the abundance of isotopomers and isotopologs, ion currents, frequencies, or optical extinctions. | ||
:''Note 3'': Relative isotope ratio differences are usually small and are therefore often expressed in units of parts per mil with symbol ?. | :''Note 3'': Relative isotope ratio differences are usually small and are therefore often expressed in units of parts per mil with symbol ?. | ||
:''Note 4'': Units of parts per thousand (ppt, 10<sup>3</sup>) or parts per million (ppm, 10<sup>6</sup>) are deprecated (IUPAC [[Green Book]]). | :''Note 4'': Units of parts per thousand (ppt, 10<sup>3</sup>) or parts per million (ppm, 10<sup>6</sup>) are deprecated (IUPAC [[Green Book]]). | ||
|rel= | |rel= | ||
Revision as of 11:54, 8 January 2014
| IUPAC RECOMMENDATIONS 2013 |
| Relative isotope-ratio difference , δ |
|---|
Measure of an isotope ratio in a sample of interest relative to a reference defined by the relation
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| Related Term(s): |
| Reference(s):
T. B. Coplen. Rapid Commun. Mass Spectrom. 25, 2538 (2011). W. A. Brand, S. S. Assonov, T. B. Coplen. Pure Appl. Chem. 82, 1719 (2010). |
| From Definitions of Terms Relating to Mass Spectrometry (IUPAC Recommendations 2013); DOI: 10.1351/PAC-REC-06-04-06 © IUPAC 2013. |
