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Development of mass spectrometric methods for structural analysis of fatty acids and estolides
Cudlman, Lukáš ; Cvačka, Josef (advisor) ; Kozlík, Petr (referee) ; Lísa, Miroslav (referee)
(EN) This doctoral thesis summarizes the use of modern mass spectrometric methods for the structural identification of fatty acids and triacylglycerol estolides (TG-EST) and their subsequent characterization in the lipidome of vernix caseosa, i.e., the biofilm covering the skin of the human fetus during the last trimester of in-utero development. Vernix caseosa has mainly antimicrobial properties and the ability to heal wounds and burns. The first part of the doctoral thesis focuses on the diversity of fatty acids in the lipidome of vernix caseosa. These acids form the structural subunits of complex lipids, such as the abundant triacylglycerols and wax esters. By studying fatty acids and their structural features, this thesis has provided valuable insights into the structural variability of the vernix caseosa lipidome. Without a full understanding of the structure of these key subunits, it would be impossible to complete the analysis of this lipidome in the future. In this thesis, fatty acids using high-performance liquid chromatography (HPLC) and modern mass spectrometry methods, namely ultraviolet photodissociation (UVPD) and ozone-induced dissociation (OzID), were characterized. The coupling of HPLC and mass spectrometry (HPLC-MS) provided unambiguous information on the positions and geometry of...
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Study of low-temperature plasma products using mass spectrometry and their relation to thin film chemistry
Maršálek, Blahoslav ; Bránecký, Martin (referee) ; Čech, Vladimír (advisor)
The aim of this thesis was to analyse and interpret the spectra of tetravinylsilane as a function of plasma discharge power in order to find a relationship between plasma products, layer deposition and thin film chemistry. Another objective was to carry out a literature search in the field of plasma-enhanced chemical vapour deposition (PECVD) and mass spectrometry. Low temperature organosilicate-based plasma technology enables the synthesis of specific materials with controlled chemical and physical properties. The targeted synthesis of surfaces with controlled properties is determined by the atomic and molecular processes in the plasma, which are responsible for building the chemical structure and the resulting material in the form of a thin film. In this work, mass spectrometry has been used to detect and quantify the particles produced in the PECVD process, which is one of the methods that allow the characterization and identification of plasma products. Analysis of the mass spectra revealed that the molecules responsible for the growth of the layer contain carbon and silicon. The deposition rate determined by in situ spectroscopic ellipsometry correlates quantitatively with the flux of carbon and silicon particles that are chemisorbed on the film surface. The ratio of carbon and silicon deposited on the surface also correlates strongly with the C/Si flux ratio of the power driven plasmas. The contribution of silicon-containing particles as building blocks to the film growth decreases with increasing power and accounts for 20% (2 W), 5% (10 W) and only 1% (75 W) of the total chemisorbed fraction. This ratio between bound silicon containing particles and carbon particles affects the elemental composition and chemical structure of the deposited layers. The relationships between plasmachemical processes and particle adhesion on the surface are quite complex. The adhesion of silicon particles first increases sharply to a maximum at 25 W and then gradually decreases, which is characteristic of the so-called precursor-deficient PECVD. Similarly, the concentration of vinyl groups incorporated into the deposited layer and the fraction of sp2 hybridization of carbon correlate with the particle fluxes of the corresponding plasma. This work has demonstrated that mass spectroscopy is a suitable method for the study of plasmachemical deposition from the gas phase (PECVD). PECVD technology is promising for the deposition of silicon-containing layers, which is technologically applicable in many directions of materials research.
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Determination of linear synthetic aromatic compounds in abiotic and biotic matrices
Tulková, Tereza ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
Synthetic musk compounds are artificial organic compounds with a smell similar to the odor of a natural musk. The most recently discovered and also the least known group of artificial musks is linear musk compounds. These substances are now often used in cosmetics, personal care products, detergents and various cleaning products. They have leaked into all the major environment components, especially into the hydrosphere. There has been great attention drawn to synthetic musk compounds in the last few years because of their environmental impact. The aim of this thesis is to identify twelve linear musk compounds (linalool, 2-cyclohexylethanol, fresco menthe, citronellol, HSA, isobornyl acetate, arocet, aroflorone, allyl cyclohexyl propionate, lilial, isoamyl salicylate and hexylcinnamic aldehyde) in waste water samples. The samples were taken at three different waste water treatment plants (WWTP) in South Moravian region (WWTP Brno-Modřice, WWTP Luhačovice and WWTP Hodonín). Each of these treatment plants has a different equivalent number of inhabitants. At first, a working method was optimized, then applied on real waste water samples. Solid-phase microextraction (SPME) technique was used for the extraction of analytes. Gas chromatography–mass spectrometry (GC/MS) was then used for identification and quantificaton of the studied compounds.
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Characterization of the chemical composition of the tar produced in the gasification of biomass
Mahelová, Zora ; Vávrová, Milada (referee) ; Čáslavský, Josef (advisor)
Biomass is a renewable source of energy and represents an acceptable alternative to fosil fuels. Usable methods of energetic use of biomass are combustion and gasification. Main interest is focused on gasification in last years. Gasification is based on conversion of organic material to usable gaseous product called syngas, which can be used as a fuel for energy production. Large amount of tar is formed as a by-product of incineration and gasification of biomass. Tar is composed by various mixture of organic substances, has a negative effect on operating conditions and is a potential threat to environment. Experimental part of this study was focused on analysis of tar obtained by gasification of various kind of biomass. Selected groups of hydrocarbons and oxygen compounds were identified in analysed samples. Individual biomass samples were compared regarding to determined relative content of selected substances. Analysis was done by complete twodimensional gas chromatography with mass spectrometric detection (GCxGC/TOF-MS).
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Use of the QuEChERS method for the analysis of fluoroquinolone antibiotics in soil
Brabcová, Kristýna ; Zlámalová Gargošová, Helena (referee) ; Mravcová, Ludmila (advisor)
The content of this master's thesis is an application of frequently used extraction method QuEChERS on soil or other samples like litter or manure containing fluoroquinolone antibiotics. In the theoretical part of this thesis are chapters describing drugs, antibiotics and antibiotic resistance. Fluoroquinolones are described in more details with their properties, appearance and behaviour in the environment. The last chapter is focused on analytical methods. In the experimental part of this thesis is chosen in accordance with available publications the most suitable extraction method. This method is tested and optimized on soil samples. The optimized method is applied on the real soil and poultry litter samples to determine the amount of ciprofloxacine and enrofloxacine. This extraction method is used on other fluoroquinolone antibiotics (norfloxacine, ofloxacine, pefloxacine, moxifloxacine) in soil. All of the samples were analyzed by LC-MS.
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Analysis of selected strobilurine pesticides in barley, malt and beer
Stehlík, Pavel ; Kočí, Radka (referee) ; RNDr.Renata Mikulíková (advisor)
This diploma work is aimed determination of strobilurine pesticide in barly, malt and berr. Identifikation of strobilurine was made according to mass spectra library and base of commercialy standard. The next quantifikation in samples was made. The work consist of three main parts refer about problems. In therotical part is the method of plant, grown protection. This part is about pesticides and their fission, history and effects. In experimental part is method for determination strobilurine. In part results and discussion are all result and data in tables a graphs. At the end is sumed up result this work.
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Structural stury of carboranes by mass spectrometry
Navrátilová, Romana ; Vávrová, Milada (referee) ; Čáslavský, Josef (advisor)
Boron cluster compounds are substances clearly synthetic, which don't exist outdoors. This group covers boranes, heteroboranes and their derivatives. They are synthesized and examined mostly for their extraordinary structural and bonding properties. Their study also brought many remarkable findings and even allowed practical use of these compounds in science and technology. This thesis is focused on the application of mass spectrometry for the identification of boranes and heteroboranes and on the study of their fragmentation mechanisms using tandem mass spectrometry on spherical ion trap.
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Analysis of aromatic compounds in plasma treated onion
Krejsová, Lenka ; Kozáková, Zdenka (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the analysis of fragrances in onions, which were exposed to plasma before planting. The adjustment was made to see if onion growth and yields would improve. The theoretical part deals with the quantitative and qualitative methods for the determination of volatile substances. It contains the principle and instrumentation of mass spectrometry as well as the tandem connection of gas chromatography with mass spectrometry. In the experimental part, a liquid sample was obtained by pressing. After 60 minutes, saturated vapors were analyzed by reactive ionization mass spectrometry (PTR-MS). Thanks to this analysis, the concentration of volatile substances was determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds, because PTR-MS does not allow distinguishing of isomers. Subsequently, the data were processed and evaluated. From the gathered obtained it is clear that the plasma treatment has an effect on the fragrances concentrations. After six months of storage, the presence of some volatile substances increased due to increased biological activity.
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Application of passive sampling for the analysis of hormones in drinking water
Remerová, Martina ; Mravcová, Ludmila (referee) ; Čáslavský, Josef (advisor)
The thesis focuses on the use of passive sampling during an analysis of hormones in drinkable water. In the theoretical part there are described selected passive samplers and the sample of the type of POCIS is described at fuller length. The next chapter engages with steroid hormones and an input of estrogenic hormone into the environment. The thesis contains chapters dealing with possibilities of the determination of hormones in water. It is specialized on the analysis of drinkable and surface water. In the last chapter of the theoretical part there are introduced water works where samples for an experimental assessment were collected from. The experimental part of the thesis presents the specification of the extraction of analytes and an adjustment of used device. In the thesis there are specific calibrations for individual assessment of hormones. The results of the assessment for each collection point are ordered to a well-arranged table. Increased levels of targeted estrogens were not approved in most of sampling points.
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