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Detailed characterization of macrocyclic glycopeptide-based chiral stationary phases in SFC
Folprechtová, Denisa ; Kalíková, Květa (advisor) ; Křížek, Tomáš (referee) ; Kohout, Michal (referee)
The choice of a suitable chiral stationary phase is a key factor for successful enantioseparation in chromatographic methods. Macrocyclic glycopeptides are chiral selectors that, due to their unique structure, allow to interact with the analyte by various types of interactions simultaneously, which contributes to their complex retention and enantiodiscrimination mechanisms. Macrocyclic glycopeptides are widely used chiral stationary phases in liquid chromatography, but they have not been thoroughly tested in sub/supercritical fluid chromatography, which currently rank among important separation techniques in terms of chiral analyses. Therefore, the aim of this thesis is a detailed characterization of the enantiodiscrimination and retention mechanisms of macrocyclic glycopeptide-based chiral stationary phases packed with core-shell particles, namely TeicoShell, VancoShell, and NicoShell columns in sub/supercritical fluid chromatography. First, the effect of the mobile phase composition, especially the type and amount of organic modifiers and additives, on individual chromatographic parameters, i.e., retention, resolution of enantiomers, and peak shapes was studied in detail using selected sets of structurally different biologically active chiral compounds and materials. Based on the obtained...
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Enantioseparations of liquid crystalline materials
Vaňkátová, Petra ; Kubíčková, Anna (advisor) ; Čabala, Radomír (referee) ; Kohout, Michal (referee)
(EN) Liquid crystalline materials are an important domain of the material science. Chiral liquid crystals (CLCs) are researched for their unique chirality-derived properties. The development of new CLCs focuses both on appropriate molecular design to fit their intended purpose and also on ways of using widely available and less expensive sources of chirality to enable cost- effective production for a potential large-scale production. Methods capable of enantioseparation are needed mainly for chiral purity control of newly synthesized CLCs and for their potential use in scaling up for preparative purpose. Nowadays, enantioselective chromatography has evolved to be the method of choice for enantioseparations. This thesis aims to establish new approaches to chromatographic enantioseparations of CLCs by developing fast and robust enantioselective methods using two different ultra-high performance chromatographic techniques - sub/supercritical fluid chromatography (UHPSFC) and liquid chromatography (UHPLC). UHPSFC is introduced and successfully employed for the first time for this purpose. For some CLCs, high values of enantioselectivity and enantioresolution were achieved, opening the possibility of scaling up to semipreparative use. In UHPLC, two modes (reversed-phase and polar organic solvent mode)...
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Impact of urban sprawl on the environment and analysis of soil sealing along the D5 highway
Keprta, Antonín ; Chuman, Tomáš (advisor) ; Šefrna, Luděk (referee)
Sub/urbanization is one of the major factors affecting the environment. Moving population and economic activities to suburb isn't always an idyllic process, but often brings many difficulties. Impacts on the natural environment are often enormous. Degradation of air quality and water quality, soil sealing and soil degradation etc. are just some of the impacts of urban sprawl on the environment. Among others include homogenization of biota, landscape fragmentation, introduction of alien species, or light and noise pollution. Pressure on the agricultural land is made by large appropriation of land and through impervious surfaces. The study evaluates the appropriation of land along the D5 highway with areas of commercial sub/urbanization. Traffic routes through the perfect time availability are the places with the greatest concentration of commercial areas today. The study showed that new commercial areas are built on the most fertile soils. Therefore the question is whether the protection of soils in the Czech Republic is sufficient. Unfinished and often missing plans of territory make often the situation even worse. Keywords: sub/urbanization, urban sprawl, pollution, soil sealing, soil protection
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