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| Titel |
Observation of Mass-Independent Fractionation in MC-ICPMS and its Implication for Accurate Isotope Ratio Measurements |
| VerfasserIn |
L. Yang, Z. Mester, R. E. Sturgeon, J. Meija |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250059563
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| Zusammenfassung |
| Today, MC-ICPMS has become a powerful research tool for the high precision isotope ratio
measurements with over five-hundred papers published annually in the past several years1-2.
However, MC-ICPMS suffers approximately tenfold larger bias (up to 25 % for lithium3) in
isotope amount ratio measurements as compared to thermal ionization mass spectrometry
(TIMS). This bias needs to be properly corrected in order to obtain accurate isotope amount
ratio measurements.
The choice of the fractionation law to calibrate (correct) measured isotope ratios is crucial
in isotope science. Over the last decades, the Russell law mass bias correction model
(Eq. 1)4 which is applicable only for mass-dependent fractionation and assumes
identical mass bias for both the calibrator and measurand elements, has become a
standard curriculum in isotope ratio measurements. However, it has been reported that
not only mass bias is different for different elements but also that the mass bias
is different for different isotope pairs of a same element5-6. Mass-independent
fractionation in MC-ICPMS has been observed for elements such as Nd, W and
Cd5-7.
Ri,j = ri,j(mi-mj)-f (1)
Here Ri,j = n(iE)/n(jE), ri,j is the measured (uncorrected) isotope ratio and E is
the element of interest, f is the fractionation function and mi,mj are the nuclide
masses.
In this talk, recent research results on MIF observed for Ge, Hg and Pb in MC-MCP in
our group8 will be presented and its implication for Russell law mass bias correction for
isotope amount ratio measurements will be presented and discussed.
References
Yang, L. Mass Spectrom. Rev. 2009, 28, 990–1011.
Personal commutation with C. B. Douthitt and Douthitt, C. B. J. Anal. At.
Spectrom. 2008, 23, 685-689.
Millot R, Guerrot C and Vigier N. Geostandards Geoanal. Res. 2004, 28:
153-159.
Russell, W. A; Papantastassiou, D. A; Tombrello, T. A. Geochim. Cosmochim.
Acta 1978, 42, 1075–1090.
Vance, D.; Thirlwall, M. Chem. Geol. 2002, 185, 227–240.
Shirai, N.; Humayun, M. J. Anal. At. Spectrom. 2011, 26, 1414–1420.
Schmitt, A. D.; Galer, S. J. G.; Abouchami, W. J. Anal. At. Spectrom. 2009, 24,
1079-1088.
Yang, L.; Mester, Z.; Zhou, L.; Gao, S.; Sturgeon, R. E.; Meija, J. Anal. Chem.,
2010, 83: 8999-9004. |
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