[Zurück]

B. Lendl:
"Extracting useful information from evolving FTIR data sets using MCR-ALS and 2DCoS: Study of Protein Folding and Intermolecular Interactions in Ionic Liquids";
Vortrag: XX. Reunion Nacional de Espectroscopia, Ciudad Real, Spanien (eingeladen); 10.09.2006 - 14.09.2006.

This paper first reviews the concepts of Two Dimensional Correlation Spectroscopy (2DCoS) and Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) for the analysis of evolving data sets.
In the first example [1] binary mixtures of water in three ionic liquids (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate (emimBF4), 1-butyl-3-methyl-imidazolium tetrafluoroborate (bmimBF4) and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) have been studied using FTIR spectroscopy. The region of OH stretching (3800 - 3250 cm-1) has been analyzed. At low concentrations only water monomers interacting with the anion of the ionic liquid exist. At higher water concentrations a second species is observed which has been assigned to a cyclic water dimmer not observed in other solvents.
The second example [2] reports on the proteolysis of BSA using proteinase K studied at 60°C again using FTIR spectroscopy. MCR-ALS applied to infrared measurements allowed the recovery of pure infrared spectra and concentration profiles of the different species involved in the reaction. Special attention was paid to the careful inspection of residuals with the use of Two Dimensional Correlation Spectroscopy. In this way, a heat-induced unfolding step previous to protein hydrolysis was identified. The infrared spectra of the intermediate species showed a more disordered structure than native albumin, being especially noticeable the decrease in -helix conformation. The formation of -sheet aggregates due to heating was detected too.

[1] M. Lopez-Pastor, M.J. Ayora-Cañada, M. Valcárcel, B. Lendl J. Phys. Chem. 110, 10896, 2006.
[2] A. Domínguez-Vidal, M. Saenz-Navajas, M.J. Ayora-Cañada, B. Lendl Anal. Chem. 78, 3257, 2006.