Resolution of infrared profiles from variable temperature experiments on mixtures and conformers in rapid equilibrium by compensating for thermal and solvent effects
✍ Scribed by Egil Nodland; Fred Olav Libnau; Olav Martin Kvalheim
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 984 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0924-2031
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✦ Synopsis
Curve resolution of infrared profiles from non-conformational mixtures and conformational equilibria is discussed. For successful resolution it is crucial that temperature and solvent induced variations observed as peak shifts and band broadening are accounted for. As changes in absorbance (in IR) or intensities (in Raman) with temperature may be different for different bands of the same conformer, the resolution must be performed on local parts of the spectra. An assumption about temperature independence of the integrated extinction coefficients in such a local region of the spectra must be made. The success of curve resolution by compensating for thermal effects is largely determined by the level of the experimental noise, the change in analyte concentrations with temperature and the thermal effects. Curve resolution of mixture spectra is illustrated using model spectra of toluene and cyclohexane and variable temperature spectra of chlorocyclohexane.