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Analytical study of reduction of ammonium perrhenate using selected reduction agents
Lišková, Jana ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This thesis is focused on analysis of reduction of ammonium perrhenate using less frequent reducing agents. Ascorbic acid and acetylhydrazine were chosen as less common reducing agents. Reductions were observed leveraging capillary zone electrophoresis and UV/Vis spectroscopy. Measurements were carried out both in acidic and in basic environments. Reduction of peak area of ammonium perrhenate was observed using capillary zone electrophoresis after addition of reducing agent. Rate of absorption of ammonium perrhenate was monitored with UV/Vis spectroscopy. Furthermore, the possibility of shifting the equilibrium of the reaction to the benefit of the reduction products was monitored by the addition of the complexing agent. Py- rogallol (benzene-1,2,3-triol) was used as the ligand and acetylhydrazine was selected as the reducing agent. The reduction was monitored by capillary zone electrophoresis. The identity of the resulting complex was confirmed with ESI/MS. Keywords rhenium, rhenium complexes, ascorbic acid, acetylhydrazine, capillary zone electrophore- sis, UV/Vis spectroscopy, mass spectrometry
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Capillary zone electrophoresis determination of protamines
Malý, Michal ; Křížek, Tomáš (advisor) ; Kubíčková, Anna (referee)
This work deals with development and optimization of a method for separation and detection of pro- tamines using capillary zone electrophoresis. The developed method uses a fused silica capillary with inner diameter of 50 µm and effective length of 41,5 cm. Driving voltage is 30 kV. Background electrolyte is aque- ous solution of 45 mmol dm−3 phosphoric acid. Analyte is detected spectrophotometrically at wavelength of 200 nm. Sample is injected hydrodynamically. The method allows for determination of protamines in the concentration range between 11 µg ml−1 to 1000 µg ml−1 , limit of detection is 4 µg ml−1 . Viablity of the method has been verified with a real sample of NPH insulin injection. For sufficiently sensitive detection of protamines in NPH insuline it is necessary to prepare the sample in acidic environment. For the pur- poses of this work the sample was acidified by addition of background electrolyte into the sample so that the background electrolyte concentration in the resulting solution of the sample was 18 mmol dm−3 . The main advantage of the method is the rapid analysis, migration time of the analyte is about 2 min. Disadvantage of the method in comparison to alternate methods using CZE or RP-HPLC is the inability to separate individ- ual protamine peptides. This disadvantage...
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Comprehensive analysis of warning and defense compounds of true bugs by high-performance separation methods
Krajíček, Jan ; Bosáková, Zuzana (advisor) ; Feltl, Ladislav (referee) ; Ventura, Karel (referee)
Insects have developed many strategies of defence against predators in the course of evolution. The evolutionarily oldest and most widely used type of defence is chemical defence, followed by acoustic or optical defence. However, many species of insects use simultaneously multiple types of warning signals, which affect different sensory receptors of the given predator. Such a complex method of warning signals is called multimodal method. It may consist of a combination of simultaneous chemical and optical signals, or a combination of acoustic and optical signalling. The combination of chemical and optical signalling used against a predator is probably the most common form of multimodal signalling. The presented work deals with the analysis of biologically active substances, which participate in the defence mechanisms of a widespread species of insects - true bugs (Heteroptera). Pterin derivatives represent a large group of natural compounds derived from pteridin, bicyclic heterocycle, and they are found in virtually all living organisms from bacteria to vertebrates. In insects, they primarily serve as pigments, resulting for example in striking coloration of cuticles of Heteroptera. The first part of the dissertation was focused on identification and quantification of pterin derivatives in cuticles...
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Complex equilibriums of beta-blockers in CZE
Kanizsová, Lívia ; Zusková, Iva (advisor) ; Jelínek, Ivan (referee)
Drugs used in the pharmaceutical industry often occur as a mixture of several isomers with a different biological activity. In a case that some isomer provides an undesirable side effect, it is important to separate it from the mixture and check the chiral purity of a drug. Capillary zone electrophoresis plays a significant role in chiral separations. A different affinity of isomers to complexation reagent is used for their separation from each other. The extent of their interaction is characterized by the complexation constant. Most commonly the cyclodextrins are used for the chiral separations of β-blockers and they could be in neutral or charged form. They probably interact with them through the creation of inclusion complexes. A successful baseline enantioseparation of all the β-blockers that have been studied, labetalol, pindolol, alprenolol and atenolol, was provided by using the background electrolyte containing charged cyclodextrins. The highest resolution of peaks was observed using sulfated cyclodextrins.
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Comprehensive analysis of warning and defense compounds of true bugs by high-performance separation methods
Krajíček, Jan
Insects have developed many strategies of defence against predators in the course of evolution. The evolutionarily oldest and most widely used type of defence is chemical defence, followed by acoustic or optical defence. However, many species of insects use simultaneously multiple types of warning signals, which affect different sensory receptors of the given predator. Such a complex method of warning signals is called multimodal method. It may consist of a combination of simultaneous chemical and optical signals, or a combination of acoustic and optical signalling. The combination of chemical and optical signalling used against a predator is probably the most common form of multimodal signalling. The presented work deals with the analysis of biologically active substances, which participate in the defence mechanisms of a widespread species of insects - true bugs (Heteroptera). Pterin derivatives represent a large group of natural compounds derived from pteridin, bicyclic heterocycle, and they are found in virtually all living organisms from bacteria to vertebrates. In insects, they primarily serve as pigments, resulting for example in striking coloration of cuticles of Heteroptera. The first part of the dissertation was focused on identification and quantification of pterin derivatives in cuticles...
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Determination binding constant of beta-blockers by capillary zone electrophoresis
Kanizsová, Lívia ; Zusková, Iva (advisor) ; Šteflová, Jana (referee)
Capillary zone electrophoresis identifies and determines various analytes based on their mobilities in a solution of the background electrolyte, which is exposed to an effect of the electric field. Besides that, it is a suitable method for determination of dissociation and complexation (stability) constants. In this paper the adrenergic β-blockers were chosen as analytes. β-blockers have at least one chiral center in the structure and separation of their enantiomers in presence of the chiral selectors by capillary electrophoresis is possible. For the enantioseparation, variously modified β-cyclodextrins are most often added to the background electrolyte. If the enantiomers of β-blockers have a different affinity to the chiral selector, they exhibit different effective mobilities. Based on a dependence of the effective mobility of analytes on the concentration of chiral selector, we are able to determine their stability constants. Key words: β-blockers, cyclodextrins, stability constant, capillary zone electrophoresis
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Mobilization of electroosmotic flow markers in capillary electrophoresis
Martínková, Eva ; Křížek, Tomáš (advisor) ; Sobotníková, Jana (referee)
Capillary zone electrophoresis is a separation method used to separate charged substances in electric field. Substances migrate to detector due to their own electrophoretic mobility and electoosmotic flow in capillary. Separation is possible because of electroforetic mobility of substances, which is directly proportional to the charge and undirectly proportional to the hydrated radius of ion. This means that neutral molecules form just one neutral zone, which is detected together. Well absorbing neutral substances are thus used as markers of average (mean) EOF. It was found, that some of the markers have dispositions to be mobilized with respect to the EOF. This mobilization is caused by interactions of free electron pair on atoms of nitrogen or oxygen of marker with components of background buffer. The aim of the study was to measure mobilization of some commonly used markers with different cations of acetate buffer and thus find "ideal" marker, whose mobility is almost the same as EOF and find combinations of marker+buffer, which are better to be avoided. Eleven markers in combination with six cations of background electrolyte were studied. We have found, that relative mobilities of some of chosen markers come up to five percent of limit mobilities of small inorganic cations. An appropriate...
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Automatic data analysis in capillary zone electrophoresis
Ördögová, Magda ; Dubský, Pavel (advisor) ; Heyda, Jan (referee)
Evaluating data in capillary zone electrophoresis usually involves many steps that require using several different programmes. Apart from evaluating the electrophoreogram itself, it is usual to process the obtained data in some other way. For example, a suitable model is fit to the data in order to obtain physical and chemical parameters of the separation (e.g. stability constant in case of complexation). It is also important to know the accuracy of the evaluation (the calculation error). In this work, new parts of the Eval programme, originally developed for electrophoreogram evaluation, were implemented. The programme now automatically estimates the Haarhoff-van der Linde function (solution of continuity equation in capillary) parameters for analyte peak. Complexing agents are often used to improve the separation in the capillary zone electrophoresis. Complexation in the capillary can be described by its physical and chemical parameters. A new part was added to the Eval programme that allows the user to fit a rectangular hyperbole function to the obtained data. Thus, the regression parameters of this dependence can be gained. The programme can also draw profile diagrams for these parameters, from which the confidence intervals can be read. An option that allows two dependencies to be fitted at...
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Interaction of pesticides - 1-naphthylacetic acid and 1-naphthylacetamide - with cucurbit[7]uril and selected cyclodextrins
Ördögová, Magda ; Dubský, Pavel (advisor) ; Beneš, Martin (referee)
This work evaluates and compares interaction of 1-naphthylacetic acid and 1-naphthylacetamide with selected complexing agents. 1-naphthylacetic acid and 1-naphthylacetamide are used as pesticides. From the viewpoint of ecology, the possibility of regulation of the photodecomposition of these pesticides is interesting. Such regulation could be for example arranged by complexation. Cyclodextrins, known for its good capability of interaction with wide spectrum of substances, were chosen as the complexing agents. Next chosen complexing agent was cucurbit[7]uril that, according to literature, could be capable of even stronger interaction than cyclodextrins. Interactions were studied by methods of affinity capillary zone electrophoresis. The strenght of single interactions was compared and if it was possible, the stability constant of the complex was determined.
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System zones in capillary electrophoresis
Riesová, Martina ; Gaš, Bohuslav (advisor) ; Kašička, Václav (referee) ; Gebauer, Petr (referee)
Martina Riesová Abstract of Ph.D. Thesis Capillary electrophoresis is a method of choice in many analytical laboratories for its high separation efficiency, rapidity, low consumption of chemicals and therefore low costs. Inherent to each electrophoretic separation system are system peaks, which can significantly affect or confuse the electrophoretic results. In capillary zone electrophoresis, position of system zones can be predicted easily and reliably by means of prediction software based on a theoretical description of electromigration. However, the prediction of only position of a system zone may not be sufficient for identification of system peaks in obtained electropherograms. Therefore, an existing theoretical model was significantly extended and new version of PeakMaster software (PeakMaster 5.3) was introduced in the framework of this thesis. PeakMaster 5.3 enables to predict not only the positions of system zones, but also their shapes and polarity. Thus, PeakMaster 5.3 improves the prediction possibility of overlapping or interaction of system peaks with analyte peaks. Moreover, composition of the sample can be optimized in order to obtain convenient shapes and amplitudes of system peaks. The applicability of capillary zone electrophoresis can be extended by addition of a complexation agent into...
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