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2-D simulations of electromigration processes
Kolivoška, Viliam ; Koval, Dušan (referee) ; Gaš, Bohuslav (advisor)
6 Abstract In the presented thesis we introduce a computational model that can be used for 2-D and 3-D computer simulations of experiments in electrophoresis. The simulations are carried out by the aid of the finite element method (FEM). In particular, commercially available program Comsol Multiphysics 3.3 is employed. A general shape of continuity equation is chosen to express the mass, electric charge, momentum and energy conservation law. Diffusion, migration and convection terms are taken into account when formulating the mass conservation law. Both external (driving voltage) and internal (diffusion currents) terms are considered in the electric charge conservation law. Both constant voltage mode and constant current mode can be handled. A solvent is regarded as an incompressible Newtonian fluid. Both pressure-driven and electroosmotic flows can be taken into consideration. The heat convection as well as the heat diffusion is governed by the energy conservation law. Both strong and weak electrolytes (of any attainable valency) may be regarded as system constituents. Furthermore, the model can handle the ionic strength correction if desired. A task may be assigned either in Cartesian or cylindrical coordinates. The presented model was employed to solve four particular tasks. The first one inspects the...
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Chiral analysis of alfa-diimine Ru(II) and Fe(II) complexes by capillary electrophoresis using sulfated cyclodextrins as stereoselectors
Sázelová, Petra ; Koval, Dušan ; Severa, Lukáš ; Teplý, Filip ; Kašička, Václav
A fast and efficient capillary electrophoretic method was developed for enantioseparation of Ru(II) and Fe(II) polypyridyl complexes using anionic randomly sulfated alfa-, beta-, and gamma-cyclodextrins (S-alfa-CD, S-beta-CD, and S-gamma-CD) and their heptakis-(2,3-diacetyl-6-sulfato)-derivatives (Ac-S-alfa-CD, Ac-S-beta-CD, and Ac-S-gamma-CD) as chiral selectors. S-alfa-CD and S-gamma-CD were found to be the best chiral selectors providing high resolutions and short analysis times. The method was applied for the assessment of chiral purity of some batches of [Ru(bpy)3]2+ catalyst.
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Study of DNA oligonucleotides interactions with ethidium bromide by partial-filling affinity capillary electrophoresis
Růžička, Martin ; Koval, Dušan ; Kašička, Václav
A partial filling affinity capillary electrophoresis was developed and applied to investigation of non-covalent molecular interactions between double stranded DNA oligonucleotide (Dickerson dodecamer) and classical DNA intercalator ligand –ethidium bromide (EtBr). Binding constants of DNA EtBr complexes were determined from the dependence of migration time changes of DNA oligomer (applied as analyte) on the length of ligand zones introduced beforehand as plugs of various lengths in hydroxypropylcellulose coated fused silica capillary. Binding constants of DNA-EtBr complex were found to be in the range 4.2 x 103 – 1.5 104 L/mol.
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Capillary electrophoresis applied to chiral analysis of helquats and characterization of their intermediates and interconversion barriers using randomly and single isomer sulfated cyclodextrins as stereoselectors
Kašička, Václav ; Koval, Dušan ; Sázelová, Petra ; Severa, Lukáš ; Vávra, Jan ; Adriaenssens, Louis ; Sonawane, Manoj R. ; Teplý, Filip
Capillary electrophoresis in acidic sodium phosphate background electrolyte, pH 2.4, with randomly sulfated alfa-, beta- and gamma-cyclodextrins as chiral selectors was applied to fast, high-resolution separation of enantiomers of a series of 35 helquats, a new class of N-heteroaromatic dicationic helicene-like species. The developed methodology was employed for evaluation of preparative enantioresolution procedures of helquats, for monitoring their racemization and for determination of interconversion barrier of helquat enantiomers.
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Capillary electrophoretic chiral analysis and estimation of helix inversion barrier of helquats using randomly sulfated cyclodextrins as chiral selectors
Kašička, Václav ; Koval, Dušan ; Sázelová, Petra ; Severa, Lukáš ; Adriaenssens, Louis ; Vávra, Jan ; Teplý, Filip
Capillary electrophoresis in acidic sodium phosphate background electrolyte, pH 2.4, with randomly sulfated alpha-, beta- and gamma-cyclodextrins as chiral selectors was employed for fast, high-resolution separation of enantiomers of a series of 24 helquats, a new class of N-heteroaromatic dicationic helicene-like species. The developed CE methodology will be utilized in the further investigation of helquats, e.g., in evaluation of their preparative enantioresolution procedures, in monitoring of their racemization and determination of interconversion barrier of helquat enantiomers.
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Enantiomer separation and determination of helix inversion barrier of helical dications by capillary electrophoresis
Koval, Dušan ; Adriaenssens, Louis ; Severa, Lukáš ; Teplý, Filip ; Sázelová, Petra ; Kašička, Václav
Enantiomeric helical forms of dicationic helquats, a novel family of charged helicene-like molecules, have been separated by capillary electrophoresis (CE) using sodium-phosphate buffer, pH 2.5, as background electrolyte and sulfated beta- and gamma-cyclodextrins as chiral selectors. Additionally, CE was used to determine barrier to helix inversion of helquats.
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