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| Titel |
Application of Fourier Transform Infrared Spectroscopy (FTIR) for assessing biogenic silica sample purity in geochemical analyses and palaeoenvironmental research |
| VerfasserIn |
G. E. A. Swann, S. V. Patwardhan |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 7, no. 1 ; Nr. 7, no. 1 (2011-02-09), S.65-74 |
| Datensatznummer |
250004397
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| Publikation (Nr.) |
 copernicus.org/cp-7-65-2011.pdf |
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| Zusammenfassung |
| The development of a rapid and non-destructive method to assess purity levels
in samples of biogenic silica prior to geochemical/isotope analysis remains a
key objective in improving both the quality and use of such data in
environmental and palaeoclimatic research. Here a Fourier Transform Infrared
Spectroscopy (FTIR) mass-balance method is demonstrated for calculating
levels of contamination in cleaned sediment core diatom samples from Lake
Baikal, Russia. Following the selection of end-members representative of
diatoms and contaminants in the analysed samples, a mass-balance model is
generated to simulate the expected FTIR spectra for a given level of
contamination. By fitting the sample FTIR spectra to the modelled FTIR
spectra and calculating the residual spectra, the optimum best-fit model and
level of contamination is obtained. When compared to X-ray Fluorescence
(XRF)
the FTIR method portrays the main changes in sample contamination through the
core sequence, permitting its use in instances where other, destructive,
techniques are not appropriate. The ability to analyse samples of <1 mg
enables, for the first time, routine analyses of small sized samples.
Discrepancies between FTIR and XRF measurements can be attributed to FTIR
end-members not fully representing all contaminants and problems in using XRF
to detect organic matter external to the diatom frustule. By analysing
samples with both FTIR and XRF, these limitations can be eliminated to
accurately identify contaminated samples. Future, routine use of these
techniques in palaeoenvironmental research will therefore significantly
reduce the number of erroneous measurements and so improve the accuracy of
biogenic silica/diatom based climate reconstructions. |
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