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Application of modern analytical methods for the study of selected boron coordination compounds
Hrušková, Helena ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This thesis is focused on the study of boron coordination compounds, specifically boron pyrogallol and 2,3-dihydroxynaphthalene ligand complexes. In the introductory part of the work are discussed the properties of boron compounds, their preparation, the possibility of separation by capillary electrophoresis and methods of structural characterization. In the first part of the thesis, the methods of preparation of complexes are discussed and for each complex the optimal yield response is chosen. The resulting products were studied by low resolution mass spectrometry. In the second part of the thesis, structures of complexes, including their modeling in the Gaussian program, were described more precisely. Furthermore, the complexes were characterized by high resolution mass spectrometry. The complexes were also studied by 11 B, 1 H and 1 H COSY NMR and IR spectroscopy. The third part was devoted to the separation of these substances from the mixture after the reaction. CE-UV and CE-MS techniques were used for this purpose. To convert the results, the separation method was developed in ammonium formate buffers that are compatible with both instruments. The equilibration between complexes and ligands was also monitored by CE-UV. A special chapter is the study of pyrogallol autooxidation by UV-VIS and...
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Spectrophotometric determination of stability constants of cyclodextrin derivatives by phenolphthalein method
Haiklová, Simona ; Dian, Juraj (advisor) ; Červený, Václav (referee)
This bachelor thesis deals with the determination of stability constants of cyclodextrins and their derivatives in the formation of supramolecular complexes with phenolphthalein. Cyclodextrins - macrocyclic oligosaccharides - are characterized by the shape of a truncated cone, whose internal hydrophobic cavity can form, with suitable substances, host-guest inclusion complexes. The formation of these inclusion complexes is accompanied by a change of a number of physicochemical parameters of the included compounds. In this bachelor thesis, the change of optical absorption of phenolphthalein, which has characteristic violet color in the alkaline area, was studied during its interaction with selected CD macrocycles. The formation of a supramolecular complex resulted in a decrease in optical absorption, which was quantified and used to determine stability constant. In the bachelor thesis, the supramolecular interaction of phenolphthalein with six derivatives of cyclodextrins were studied - basic cyclodextrins β-CD a γ-CD and their two derivatives. In the selected derivatives of these CDs the -OH groups in positions 2, 3, and 6 were replaced either by hydroxypropyl groups (hydroxypropyl-β-CD and hydroxypropyl-γ- CD) or (randomly) by methyl groups (RaMe-β-CD and RaMe-γ-CD). For these CD derivatives, the...
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Chemiluminescent determination of vitamin B12 using sequential injection analysis
Doležalová, Veronika ; Hraníček, Jakub (advisor) ; Dian, Juraj (referee)
This bachelor thesis deals to find the optimal conditions for the determination of vitamin B12 by the Sequential Injection Analysis (SIA). The basis of the determination is a chemiluminescence reaction in which luminol is oxidized by hydrogen peroxide under the catalysis of cobalt ions in a basic medium. The intensity of the chemiluminescence radiation was measured using a spectrofluorometric detector and the measured intensities were recorded. Suitable experimental conditions were found experimentally before the actual determination. A total of 4 parameters were optimized, namely, the mass percentage of hydrogen peroxide, the ratio between the dosed cobalt ion sample and the luminol solution, the sample flow rate and the luminol concentration. Under optimized conditions, several solutions of known cobalt ion concentration were measured, from which a calibration dependence of chemiluminescence intensity on cobalt ion concentration could be established. For this determination, the basic characteristics were determined. For the determination of vitamin B12 itself by the SIA technique, it was assumed that the vitamin molecule contains exactly one cobalt atom, which was released from the molecule by the action of UV radiation. At the end of the work, the concentration obtained by the measurement was...
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Cluster studies in molecular beams
Profant, Václav ; Dian, Juraj (advisor)
In the present work we study properties of clusters of small heteroatomic molecules with biological relevance by several experimental methods based on molecular beams. In the first experiment structure and dynamics of size-selected charged pyrrole clusters have been studied by means of molecular beam scattering experiment. Small neutral Pyn clusters were produced in Py/He expansions and larger mixed PynArm clusters in Py/Ar expansions, and the scattering experiment with a secondary beam of He atoms was used to select the neutral clusters of dierent sizes. The complete size-selected fragmentation patterns for the neutral dimer to tetramer after an electron impact ionization at 70 eV from the measurements of the angular and velocity distributions at dierent fragment masses. In second experiment photolysis of size selected pyrrole, imidazole and pyrazole clusters has been investigated. Comparison with the photolysis of an isolated molecules and between studied systems has been made. Clusters were photolyzed at 243 and 193 nm and the kinetic energy distributions of the H-photofragments have been measured and analyzed. Finally the mass spectra of the fragments after multiphoton ionization have been measured. The significant inuence of the cluster environment to the photolytic behavior was observed and discussed.
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Derivatization of the micro-samples of natural polymers with similar composition for FTIR analysis
Dudičová, Dorota ; Červený, Václav (advisor) ; Dian, Juraj (referee)
in English This master thesis is focused on verifying the possibility of optimizing FTIR spectrometric analysis of terpenic resins using derivatized (fluorinated) samples using XtalFluor-E in combination with triethylamine trihydrofluoride as an agent. Terpenic resins have very similar FTIR spectra, so for their better differentiation, they need to be derivatized to minimize the influence of overlapping spectral bands in FTIR spectra. This work aimed to create a methodology for derivatization of samples of natural polymers for the National Technical Museum in Prague, where the work was performed. Samples of terpenic resins were measured non-fluorinated by the ATR crystal method and by transmission, after fluorination, only the ATR crystal method was used. Different fluorination conditions, different times (2, 4, 6, 24 and 96 hours), the effect of sample rinsing (diethyl ether, ethylene tetrachloride) and the effect of matrix on the sample (KBr pellet) were tested. Fluorination has shown to be effective. Four hours of fluorination and the need to rinse the sample with diethyl ether were chosen as the optimal fluorination conditions. After testing the resins themselves, fluorinated samples of violin varnishes and samples of historical varnishes from harp and piano were analyzed. Their spectra before...
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Optimization of experimental setup for chemiluminescent determination of cobalt ions
Pastrňáková, Aneta ; Hraníček, Jakub (advisor) ; Dian, Juraj (referee)
The presented thesis deals with finding the optimal experimental setup for the chemiluminescent determination of cobalt ions by the technique of flow injection analysis (FIA) and sequential injection analysis (SIA) and comparing the achieved results of the determination. The determination is based on a chemiluminescent reaction, essence of which is oxidation of luminol with hydrogen peroxide in an alkaline solution in a flow system in the presence of cobalt ions, which acts as a catalyst of the reaction. In the experimental part of the work, a suitable setup for the detection of chemiluminescent light emission was found, followed by a suitable setup of the FIA and SIA systems for the determination of cobalt ions. For the detection of radiation, a glass spiral tube was selected, which was the most suitable for chemiluminescent measurement, compared to other experiments performed with different. In the next part of the work, optimal conditions for cobalt ions determination were experimentally found. As for the FIA technique, the volume flow rate of hydrogen peroxide, luminol and cobalt ions solutions was optimized. Furthermore, the concentration of the hydrogen peroxide solution and luminol. Last but not least, the dosing volume of the cobalt ions solution and the pH of the luminol solution were...
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Spectroelectrochemical study of porphyrin derivatives in non-aqueous solvents
Povišer, Martin ; Dian, Juraj (advisor) ; Pšenčík, Jakub (referee)
Porphyrins and their derivatives constitute an important group of com- pounds taking part in vital biological processes such as transport of oxygen in blood and in photosynthesis. Electrochemical experiments such as cyclic volta- mmetry allow to examine the energetic balance of oxidation and reduction pro- cesses of particles under study. In spectroelectrochemical studies, the experiment is extended with optical characterization of the arising oxidized or reduced spe- cies. These are means to study of electronic structure of species and available electron transitions. Such studies are especially interesting in case of porphyrins due to possible elucidation of electron transfer in photosynthetic chains. This work presents: (a) an elementary theoretical treatment of electrode reactions fun- damental for electrochemical experiments, (b) description of the experimental realization of spectroelectrochemical study of porphyrins and derivatives in non- aqueous solvents, and (c) results of original spectroelectrochemical measurements on protoporphyrin IX in medium dimethylformamide. 1
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Characterization of new complex-forming agents for CZE
Málková, Nikola ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This diploma thesis is focused on the use of modern instrumental analytical techniques for analytical evaluation and study of new complex-forming agents. Precise characterization of complex-forming agents is necessary to determine their potential use in scientific researches. These compounds are often used in analytical chemistry e.g. for kinetic determination of metal ions, as reagents for complexometric titrations and also for chiral separations of enantiomers. The dependences of effective electrophoretic mobilities of newly synthesized macrocyclic complex-forming agents on pH of a background electrolyte were measured by using CZE. This dependency is discussed further in the thesis. The thermodynamic dissociation constants of the studied compounds were determined too. Analysis by molecular UV/VIS spectrometry, infrared spectroscopy and mass spectrometry were also performed. The addition of the studied complex-forming agents to the separation of a mixed sample of fumaric acid and maleic acid was also studied. Knowledge of the chemical and physical properties of new substances contributes to the understanding of their chemical behavior and the determination of their application. This knowledge can be also very useful in scientific research, which these compounds are already involved in....
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Photoluminescence sensor field applied for detection of chemical compounds in gas mixtures
Liška, Jiří ; Dian, Juraj (advisor) ; Broncová, Gabriela (referee)
Title: Photoluminescence sensor field applied for detection of chemical compounds in gas mixtures Author: Jiří Liška Department: Department of Analytical Chemistry Supervisor: doc. RNDr. Juraj Dian, CSc. Abstract Porous silicon is a nanostructured material that can be prepared by galvanic etching of silicon in the presence of hydrofluoric acid. The properties of this material can be influenced by way of preparation or by the chemical modification of the surface. Porous silicon has many extraordinary properties as compared to macrocrystalline silicon; the most important one for chemical sensing is the visible photoluminescence at room temperature. In the presence of organic and inorganic analytes in the gas phase, the photoluminescence of the material is quenched. This phenomenon can be used for chemical sensors of chemical compounds in the gas phase. These sensors are very sensitive and give reasonable results for organic compounds. Photoluminescence sensor field uses for measurement several sensor elements with the modified surface. It is possible to use this method for the identification and determination of gaseous organic compounds. The aim of this thesis was: 1. the preparation of porous silicon samples, 2. the modification of surface with different methods, 3. the characterization of samples with FTIR...
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Application of modern analytical methods for the study of selected boron coordination compounds
Hrušková, Helena ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This thesis is focused on the study of boron coordination compounds, specifically boron pyrogallol and 2,3-dihydroxynaphthalene ligand complexes. In the introductory part of the work are discussed the properties of boron compounds, their preparation, the possibility of separation by capillary electrophoresis and methods of structural characterization. In the first part of the thesis, the methods of preparation of complexes are discussed and for each complex the optimal yield response is chosen. The resulting products were studied by low resolution mass spectrometry. In the second part of the thesis, structures of complexes, including their modeling in the Gaussian program, were described more precisely. Furthermore, the complexes were characterized by high resolution mass spectrometry. The complexes were also studied by 11 B, 1 H and 1 H COSY NMR and IR spectroscopy. The third part was devoted to the separation of these substances from the mixture after the reaction. CE-UV and CE-MS techniques were used for this purpose. To convert the results, the separation method was developed in ammonium formate buffers that are compatible with both instruments. The equilibration between complexes and ligands was also monitored by CE-UV. A special chapter is the study of pyrogallol autooxidation by UV-VIS and...
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