Vitenskapelige artikler m/referee

Correcting attenuated total reflection–Fourier transform infrared spectra for water vapor and carbon dioxide.

 

Fourier-transform infrarød spektroskopi, som Matforsk nylig har investert mye nytt utstyr for, har et stort potensial for metabolomisk hurtig-profilering. For eksempel kan det brukes til in vivo overvåking av cellekulturer i vekst. Men ukontrollerte variasjoner i vanndamp og CO2 i luften rundt prøvene genererer store og generende interferenser.

Denne artikkelen viser en ny teknikk til matematisk å estimere og fjerne det meste av disse uønskede gasseffektene i FTIR spektra. Både de estimerte gassmodell-parametrene og programvaren for dette er lagt ut på hjemmesiden til Center for Biospectroscopy and Data Modelling (www.umb.no/specmod).

Nøkkeldata

Årstall 2006
Abstract Fourier transform infrared (FTIR) spectroscopy is a valuable technique for characterisation of biological samples, providing a detailed fingerprint of the major chemical constituents. However, water vapour and CO2 in the beam path often cause interferences in the spectra, which can hamper the data analysis and interpretation of results. In this paper we present a new method for removal of the spectral contributions due to atmospheric water and CO2 from attenuated total reflection (ATR)-FTIR spectra. In the IR spectrum, four separate wavenumber regions were defined, each containing an absorption band from either water vapour or CO2. From two calibration data sets, gas model spectra were estimated in each of the four spectral regions, and these model spectra were applied for correction of gas absorptions in two independent test sets (spectra of aqueous solutions and a yeast biofilm (C. albicans) growing on an ATR-crystal, respectively). The amounts of the atmospheric gases as expressed by the model spectra were estimated by regression, using second derivative transformed spectra, and the estimated gas spectra could subsequently be subtracted from the sample spectra. For spectra of the growing yeast biofilm, the gas correction revealed otherwise hidden variations of relevance for modelling the growth dynamics. As the presented method improved the interpretation of the principle component analysis (PCA) models, it has proven to be a valuable tool for filtering atmospheric variation in ATR-FTIR spectra.
Referanse Bruun, S.W., Kohler, A., Adt, I., Sockalingum, G.D., Manfait, M., Martens, H. 2006. Correcting attenuated total reflection–Fourier transform infrared spectra for water vapor and carbon dioxide. Applied Spectroscopy, Vol 60, No. 9, pp 1029-1039.
Utgiver Applied Spectroscopy,

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  • Achim Kohler

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  • Harald Martens

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