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The study of the electrochemical and chemical oxidative degradation of salicylic and acetylsalicylic acid
Tonnerová, Barbora ; Kubíčková, Anna (advisor) ; Křížek, Tomáš (referee)
The aim of this Thesis was to study the degradation of salicylic acid by the electrochemical oxidation. The electrochemical oxidation of salicylic acid was compared to the electrochemical oxidation of acetylsalicylic acid. Two electrochemical cells were tested - batch cell and thin- layer flow-cell. The newly developed and validated method of ultra-high performance liquid chromatography has been used to analyse the degradation products, salicylic acid and acetylsalicylic acid. The optimal analysis was made by the Kinetex column C18 (2,1 x 100 mm; 1,7 µm) and mobile phase with two components - acetonitrile and water with addition of 0,1% formic acid. These two components of the mobile phase were mixed by the gradient program from 10 % to 60 % (v/v) acetonitrile. The mobile phase flow was set to 0,3 ml min-1 and the volume of injection was 2 µl. The detection was performed by photodiode array detector at the wavelength 240 nm. Total time of the analysis was 11 minutes. The electrochemical degradation has been studied by an anodic oxidation in a flow cell with a boron-doped diamond (BDD) anode and a stainless-steel cathode. The samples of salicylic acid and acetylsalicylic acid was dissolved in the ammonium acetate, concentration 200 mmol dm-3 at pH=4,0. The 20 % oxidation rate of salicylic acid was...
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Separation and determination of possible products of enzymatic cleavage of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside using capillary electrophoresis
Velvarská, Romana ; Křížek, Tomáš (advisor) ; Kalíková, Květa (referee)
This work deals with the development and optimization of conditions of a method that can be used to compare the activity of the enzyme β-N-acetylhexosaminidase in hydrolysis of a natural substrate and a chromogenic substrate, which is often used in the study of enzyme kinetics. As a substrate, 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside was selected for cleavage. This oligosaccharide contains bond, which the enzyme cleaves in the natural substrate, and the bond that occurs in the chromogenic substrate. To determine the products arising from enzymatic hydrolysis of 4-nitrophenyl-N,N'-diacetyl-β-D-chitobioside, capillary zone electrophoresis was used. First, it was necessary to find the optimal composition of the electrolyte, its pH and concentration. The optimal background electrolyte was a solution of sodium tetraborate at a concentration of 25 mmol/l and a pH of 10.25. Subsequently, repeatability, calibration curves and linearity, limit of detection and limit of quantification were investigated. Repeatability of migration times ranged up to 0.6%, the repeatability of peak areas between 2.5 and 6.3%. Limits of detection were ranging from 0.005 to 0.120 mmol/l. Finally, the optimized method was successfully used to monitor the actual enzyme cleavage.
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Czech atomic law
Křížek, Tomáš ; Drobník, Jaroslav (advisor) ; Damohorský, Milan (referee)
The Czech Nuclear law The Nuclear law is an importnat part of the Environmental law. The Nuclear law regulates the peaceful use of nuclear energy and of inonizing radiation, which are the activities potentially dangerous for the environment. This area is a component of a special part of the Environmental law. The ionizing radiation is classified as a particular source of hazard to the environment. This diploma thesis deals with the Czech Nuclear law, and that by means of characterization of a valid legal regulations in the context of international and European law and by means of an analysis of the questions of building and operation of nuclear power stations in Czech republic. The main source of the Czech legal regulation is the Act No. 18/1997 Coll., on peaceful use of nuclear energy and ionizing radiation (Nuclear law) and changes and amendments of some laws. The Nuclear law is a high-quality legal regulation of the peaceful use of nuclear energy and ionizing radiation, which respects the requirements of the international and European law, comparable with the legal regulations of other advanced countries. After a short presentation of the history of development of nuclear energy and ionizing radiation use, the first part of this thesis oulines both the international and European legal regulations of this...
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The club development of american football in the Czech Republic
Dundáček, Jan ; Janák, Vladimír (advisor) ; Křížek, Tomáš (referee)
Title: The club development of american football in the Czech Republic In the first part of this thesis American football is introduced, explaining basic game principles and describing the game so that the reader can imagine what the sport is all about. The second part then focuses on examining the emergence of particular American football clubs in the Czech Republic. The whole period is divided into several stages, with a strong focus on finding a common denominator of individual events. The aim is to map American football in the Czech Republic since the establishment of the first club up to the present with emphasis on main themes and key periods. Recording individual events from the perspective of history is an important element for any future research. Keywords: American football, development, club, origin, history, Czech Republic
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Determination of proteinogenic amino acids by high-performance separation techniques
Hodek, Ondřej ; Křížek, Tomáš (advisor) ; Pacáková, Věra (referee) ; Tůma, Petr (referee)
(EN) Proteinogenic amino acids are key components of living organisms. Thus, the latest metabolomics research has focused on developing fast and sensitive methods for the determination of amino acids. In this context, this thesis contains two studies describing development of high-performance separation techniques for the quantification of amino acids. In the first study, a capillary electrophoresis method was developed for the determination of free amino acids in tobacco plants, particularly focusing on optimizing the extraction of amino acids from solid plant materials. The extraction procedure was optimized using design of experiments (DoE) to obtain the highest possible extraction yield of amino acids. Factors such as volume and concentration of the extraction solvent (hydrochloric acid) were assessed as the most significant. Subsequently, the optimal values of these factors were determined using response surface methodology (RSM). Lastly, proteinogenic amino acids were quantified using capillary electrophoresis with contactless conductivity detection and calibration with internal standard, which improved the precision of the method. The second study aimed at developing a supercritical fluid chromatography method for the determination of free proteinogenic amino acids in human plasma. The most...
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Development of high-performance liquid chromatography methods for determination of major components of tobacco
Rozkovcová, Lucie ; Jelínek, Ivan (advisor) ; Křížek, Tomáš (referee)
The aim of this work was development of high-performance liquid chromatography method with DAD detection for determination of nicotine in tobacco. Standard operating procedure used by World Health Organization was chosen as comparison of the developed method. Optimized high performance chromatography method is suitable for determining nicotine in tobacco. Limit of detection for this method was 0,0003 mg/ml and limit of quantification was 0,0010 mg/ml. Optimization of preparation of samples was significant part of this thesis. Sample preparation procedure was made substantially easier in comparison to other commonly used methods. Nicotine content was determined from real tobacco leaves samples, cigarette tobacco filler, nicotine cartridge for electronic cigarettes and pipe tobacco. Satisfactory relative standard deviation was achieved for all types of samples. Next part of this thesis focused on study of determining polyphenols using high-performance liquid chromatography with diode array detector. Chosen analytes were chlorogenic acid, caffeic acid, rutine, scopoletine and quercitrine. Among the five tested analytes, the highest sensitivity was achieved for chlorogenic acid and caffeic acid. All of the analytes achieved low limits of detection and quantification. Key words Liquid chromatography,...
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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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