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Investigation of calibration factor stability for GC-FID analysis of alcoholic products quality by internal standard methods
Čermáková, Veronika ; Čabala, Radomír (advisor) ; Coufal, Pavel (referee)
This thesis focuses on measuring calibration factors and the dependence of their stability on experimental conditions for the purpose of quality control and the safety of alcoholic beverages using gas chromatography with flame ionization detection (GC-FID). Ten volatile compounds (acetaldehyde, methanol, methyl acetate, ethyl acetate, 1-propanol, 1-butanol, 2-butanol, isobutanol, acetal, 3-methyl-1-butanol) were monitored according to the legal regulations of the European Commission. These target compounds were analysed in prepared solutions under 27 different measurement conditions. Taguchi's multifactorial statistical method was used to determine the influence of individual measurement parameters on the stability of calibration factors. The chosen variables for measurements were matrix composition, concentration of volatile compounds, GC injector temperature, sample injection volume, injection split ratio, and detector temperature. Within the experiments, each of these variable factors took one of three possible values. Relative response factors (RRF) for each analysed compound were compared using two internal standard (IS) methods. One method utilised commonly used 1-pentanol as the internal standard, while in the other, ethanol, the main component of all alcoholic beverages, was used as the...
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Biosynthesis of polyhyroxyalkanoates in non-suflur purple bacteria
Fiala, Tomáš ; Vodička, Juraj (referee) ; Obruča, Stanislav (advisor)
This bachelor thesis focuses on polyhydroxyalkanoates (PHA) and their production using non-sulfur purple bacteria, specifically Rhodospirillum rubrum. The cultivation conditions were optimized especially with respect to the determination of NaCl concentrations for the following evolution experiments. Then this microorganism was repeatedly cultured at a high concentration of NaCl (40 g/L). Passage system was used in this cultivation with 48 h between inoculations under aerobic conditions in the dark. In the samples cultivated in this way, the growth rate was investigated using optical density and the amount of biomass and PHA using gas chromatography with an FID detector. As the last experiment PCR analysis was performed to test the 16S rRNA and phaC genes. The conclusion of the work is the successful adaptation of R. rubrum to a concentration of 40 g/l NaCl. Furthermore, the positive effect of stress stimulus on the increased PHA production was proven.
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Biocrystallization as a new concept in development of piezoelectronics for use in biomaterials
Dobešová, Kateřina ; Plichta, Tomáš (referee) ; Sedláček, Petr (advisor)
This thesis focuses on biofilament methods and biocrystallization of bacterial cells producing polyhydroxyalkanoates, specifically the bacterium Cupriavidus necator H16. The main techniques used for cell orientation include spin-coating and acoustic waves. Biocrystallization was induced by temperature, osmotic, and acid stress. The degree of cell orientation was monitored by an atomic force microscope, and crystallization was determined by FTIR. Among other parameters, the thickness of the layers was evaluated using a profilometer. The amount of PHA in the bacterial cells was determined by gas chromatography. The preparation of crystalline ordered layers of biomaterials represents a route to piezoelectric biomaterials.
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Biotechnological production of polyhydroxyalkanoates employing extremophilic purple bacteria
Rubanová, Blanka ; Samek, Ota (referee) ; Obruča, Stanislav (advisor)
The presented thesis focuses on studying the metabolism of polyhydroxyalkanoates (PHAs) in extremophilic purple bacteria, specifically Rhodoblastus acidophilus and Rhodobaca barguzinensis. The bacteria's ability to synthesize PHAs was examined in various media and using different carbon sources. Initially, optimal conditions including media volume, light presence, cultivation duration, and inoculum size were determined for the most suitable bacterial growth. Subsequently, the PHA content in bacteria cultivated in different media and with various carbon sources was analysed using gas chromatography. For a better characterization of bacterial metabolism and morphology, scanning transmission electron microscopy (STEM) and Fourier-transform infrared spectroscopy (FTIR) were used. The bacteria's ability to synthesize PHA was also examined at the genotype level using polymerase chain reaction (PCR) method. The presence of the phaC gene, encoding PHA synthase class I, was detected in bacterial DNA. Additionally, an experiment was conducted to cultivate bacteria under conditions favourable for the synthesis of microbial pigments (carotenoids and bacteriochlorophyll a). The absorption spectrum of extracted pigments was measured using UV-VIS spectroscopy.
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Studz of direct and indirect plasma application on onion seeding bulbs
Krejsová, Lenka ; Enev, Vojtěch (referee) ; Krčma, František (advisor)
Nowadays, agriculture is based on conventional methods that involve the application of pesticides, agricultural chemicals and fertilizers. These substances have a negative impact on nature and human health, so more environmentally friendly methods are being sought. This thesis deals with the analysis of fragrances in onions treated with plasma before planting. The treatment was carried out to see if it would improve onion growth while maintaining or increasing the fragrance content. The theoretical part deals with the soil and it is characterization methods, plasma, quantitative and qualitative methods for the determination of volatile substances. It contains the principles of UV-VIS spectrometry, atomic absorption spectrometry (AAS), mass spectrometry (MS) as well as tandem connection of gas chromatography with mass spectrometry (GC–MS). The experimental part was carried out over a period of three years at 22 sites. The preparation and analysis of soil samples are described, which was also evaluated. Furthermore, the procedures for treating the bulbs with corona discharge and plasma-activated water before planting were described. In total, four treatment variants were carried out and bulbs from the fifth variant were not additionally treated. Each treatment variant was planted in four replications of ten bulbs each. Twenty selected grown onions from one site were individually converted to liquid samples and the saturated vapor was analysed by proton transfer reaction time of flight mass spectrometry (PTR–TOF–MS). Thanks to this analysis, the concentrations of volatile substances were determined. Some samples were analyzed by gas chromatography with mass spectrometer as detector to identify the compounds. Subsequently, the data were processed and evaluated. From the results obtained, it is evident that plasma treatment can be useful for the treatment of onions in agriculture, because it confirmed harvest increase without decrease of fragrances concentrations. Thus, it is necessary to carry out experiments on a larger scale in the future.
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Flame retardants and their penetration into the terrestrial ecosystem
Chytil, Václav ; Čáslavský, Josef (referee) ; Vávrová, Milada (advisor)
This diploma thesis was focused on the analysis of four compounds from brominated flame retardants group, namely pentabromoethylbenzene, hexabromocyclododecane, hexabromobenzene and tetrabromobisphenol A. Matrices were represented by four soil samples and four seat of fire samples. In addition, bisphenol A was also determined. First of all, process of extraction of analytes from matrices was optimized. Three different extraction techniques were tested (pressurized solvent extraction, microwave-assisted extraction and ultrasound-assisted extraction). Next step was to verify stability of target compounds in strongly acidic conditions and to optimize clean-up of extract by column chromatography. Gas chromatography with electron capture detection (GC-ECD) was chosen as an appropriate analytical method for the determination of brominated flame retardants. Bisphenol A was determined by gas chromatography with mass spectrometric detection (GC-MS). The derivatization of phenolic analytes before their final analytical determination was also essential.
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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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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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