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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Charakterizace nových chirálních separačních systémů pro použití v HPLC / Characterization of new chiral separation systems for HPLC

Vozka, Jiří January 2014 (has links)
The dissertation thesis is focused on the physico-chemical characterization of interaction mechanisms of chiral stationary phases based on derivatized cyclofructans. Correct interpretation of retention and enantiodiscrimination processes substantially facilitates the development and optimization of new enantioselective methods using cyclofructan-based chiral stationary phases. At first, the interaction mechanisms of three commercially available cyclofructan-based stationary phases were studied in normal-phase mode of liquid chromatography. Namely, systems using chiral stationary phases based on dimethylphenyl carbamate cyclofructan 7, R-naphtylethyl carbamate cyclofructan 6 and isopropyl carbamate cyclofructan 6 were studied. Linear free energy relationship model was used as a basic tool for characterization of interactions on the stationary phases. The mentioned model revealed that the main interactions contributing to retention in cyclofructan-based systems are hydrogen bond acidity and dipolarity/polarizibility, while dispersion interactions cause decrease of retention. The impact of oligosaccharide skeleton of the cyclofructan selector on the enantioselectivity was elucidated by the comparison with seemingly analogous cyclodextrin-based chiral stationary phases. Cyclofructan-based chiral...

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