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Separation of Azaarenes by High Performance Liguid Chromatography
Kočí, Kamila ; Friedl, Zdeněk (referee) ; Večeřa, Zbyněk (referee) ; Ventura, Karel (referee) ; Šimek, Zdeněk (advisor)
Under the framework of this PhD project, a study on chromatographic behaviour of selected azaarenes on octadecylsilica stationary phases during their separation by reversed phase liquid chromatography was developed. The main goal was aimed at an application of the basic RPLC principles on the retention behaviour of azaarenes including the effects such as peak tailing, peak broadening, irreproducible retention or strong retention on a stationary phase. This study was particularly focused on basic azaarenes, also called acridines, which belong to a group of persistent organic pollutants providing mutagenic and/or carcinogenic activity. The retention patterns were studied on a group of eight acridines that are often present in environmental samples polluted with polycyclic aromatic compounds. The mixture of acridines was separated under isocratic elution conditions on three octadecylsilica stationary phases using two different binary mixtures as a mobile phase. Evaluation of the surface properties of the selected stationary phases was firstly performed, followed by the separation experiments. The structure of the experiments was designed to evaluate the effect of three different factors on the retention behaviour of acridines: properties of a stationary phase, composition of a mobile phase and physical-chemical properties of acridines. The treatment of the results was based on the capacity factor values providing the best fitting and repeatability of data, but other parameters that evaluate thermodynamic and kinetic aspects of the separation process were also given. Simple correlations between the three factors and a character of retention mechanism of acridines on the given separation system were found. Application of this knowledge simplifies an optimisation process and helps to solve common separation problems for acridines, but also for other basic analytes displaying similar physical-chemical properties (Mr and pKa).
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Modern detection methods of energetic materials
Šesták, Jozef ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
The review of modern detection methods of explosives was composed. Firstly the thesis deals with the detection methods commonly used in forensics science such as gas chromatography, mass spectrometry, ion mobility spectrometry, Raman spectroscopy and mainly their innovations. Then the thesis is focused on simple but very sensitive methods using fluorescence and chemiluminescence. At the end a methods as the results of a latest research are mentioned. The main of them are micro cantilever sensors and differential reflectometry. Security and counterterrorist warfare is main point of thesis.
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Nitramide-based energetic materials
Křištof, Adam ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
Homolytic dissociation of the N-NO2 bond represents primary fission process of energetic materials under the influence of heat, impact, vibration and electric spark. The fission of nitramide bonds is characterized by homolytic bond dissociation energy BDE(RCON-NO2) or disproportionation bond energy DISP(RCON-NO2), which is expressed by an isodesmic reaction RCON-NO2 + SCON-H › RCON-H + SCON NO2, where SCON NO2 is a standard nitramide (1-nitropiperidin-2-on, NPO). This kind of virtual chemical calculation cancels the effect of electron correlation, accompanying the theoretical calculations of free radicals. In this thesis, the homolytic dissociation bond energy BDE(RCON-NO2) and disproportionation bond energy DISP(RCON-NO2) were evaluated for 13 cyclic nitramides using the DFT B3LYP/6-311+G(d,p) method and at the same time the total charges of corresponding nitro groups Q(NO2) were calculated by DFT B3LYP/6-31G(d,p) method. The evaluated BDE and DISP energies were correlated with detonation parameters as squares of detonation velocities and detonation heats. The resulting relationships allow a more detailed description of dependence between the molecular structure of evaluated nitramides and their explosive properties.
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Chemistry of linear polynitramines
Teplá, Romana ; Bednařík, Karel (referee) ; Friedl, Zdeněk (advisor)
This work is focused on chemistry of linear polynitramines, their physical-chemical and explosive properties with regards to the possibility of their preparation and field of utilization as energetic plasticizers of solid propellants and smokeless powder. The use of linear polynitramines as plasticizers or energetic binders is influenced by melting temperature which increases with the number of C-N(NO2)-C units in molecule of energetic material. Linear polynitramines with lower melting temperature are utilized as plasticizers of solid propellants and smokeless powder additives. Linear polynitramines with longer chain and consequently with higher melting points could be used as binders or energetic components of rocket propellants.
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Detection methods of energetic materials
Procházka, Michal ; Diviš, Pavel (referee) ; Friedl, Zdeněk (advisor)
A research on current methods of detection of explosives and related materials was made. At first the thesis studies methods of detection and analysis of explosives including chromatographic methods (TLC, GC, HPLC, IC), mass spectrometry and its variations, ion mobility spectrometry and infra-red spectroscopy. Next the attention is placed on detection of explosives in solid phase by X-ray detection, nuclear magnetic and quadrupole resonance and thermal neutron activation. Practical applications of these methods are of great importance in this thesis as well as their usage in the counterterrorist fight.
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Thermochemical properties of linear polynitramines
Teplá, Romana ; Pekař, Miloslav (referee) ; Friedl, Zdeněk (advisor)
The work is focused on the obtaining thermochemical properties of the linear polynitramines to predict their detonation properties. The basic thermochemical parameters are enthalpies ?f H° (298,g) in the gas and solid phase as well. The values of the enthalpy in the gas phase were obtained at a theoretical level by quantum chemical DFT calculations using both an isodesmic reactions and direct thermochemical G-Gaussian recipes. Conversion to the enthalpy in the solid phase ?f H° (298,s) was carried out using sublimation enthalpies ?s H° (298,g) obtained on the empirical level. The results were mutually compared and correlated with the structure of the linear polynitramines.
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The Usage of Separation Methods for Research of Biologically Active Substances in Waters
Vydrová, Lucie ; Friedl, Zdeněk (referee) ; Opatřilová, Radka (referee) ; Chýlková,, Jaromíra (referee) ; Vávrová, Milada (advisor)
Pharmaceuticals are biological active compounds with different functional groups, physico-chemical and biological properties. These chemical compounds are called as “new contaminants” which cumulate in various environmental components. These contaminants input to environment from industrial processes, hospitals and health care institutions or household sources and these pollutants can to negatively interact with environmental components. Pharmaceuticals are separated according to structure and their effects to live organisms. On the basis of drug consumption in Czech Republic the non-steroidal anti-inflammatory drugs are the most using pharmaceuticals, because these drugs can be obtain without prescriptions. The choosing analgesics for study were monitored in waste water from waste waters treatment plant (WWTP Brno – Modřice) and in surface water from two sampling sites of river Kretinka. Pharmaceuticals were monitored in surface waters in Czech Republic, in Scotland (river Thurso) and in Taiwan (river Erren, Agongdian, Yanshuei and canal of Tainan) Solid phase extraction (SPE) is used for extraction of study pharmaceutical from water system. The high performance liquid chromatography (HPLC) with diode array detection or mass spectrometry was used for determination of drugs in surface waters from Czech Republic. The water samples from Scotland and Taiwan were analysed and the high performance liquid chromatography with mass spectrometry (HPLC/MS) was used for determination of pharmaceuticals. The method of HPLC/MS enables the determination of study compounds in the very low range of concentrations (ng ? l-1). All monitored pharmaceuticals were identified and quantified in water samples from river Kretinka in Czech Republic, river Thurso (Scotland) and rivers Erren, Agongdian, Yanshuei and canal of Tainan in Taiwan and the obtained data were compared.
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