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Characterization of microfludic chips
Vejrosta, Jakub ; Enev, Vojtěch (referee) ; Venerová, Tereza (advisor)
Nowadays, when we are moving to smaller and smaller scales, microfluidics is being used, which helps us to move from fluid devices to the dimensions of microfluidics, which may have a great application in the future. This work deals with the correct preparation and production of a microfluidic chip. Which consist of two parts. One part is the polydimethylsiloxane (PDMS) part of the chip, and the other is the coverslip. In this work, the production process of this chip is improved. The functionality of these chips and the time dependence of the age of the chip and the polydimethylsiloxane from which the chips are made were tested using fluorescence microscopy.
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Use of thin layer chromatography for fractionation and characterization of organic matter isolated from alginite
Solanský, Pavel ; Sovová, Šárka (referee) ; Enev, Vojtěch (advisor)
This diploma thesis is focused on the study of structure and physicochemical properties of organic fractions of humic substances, which were obtained by the method of thin-layer chromatography. Humic substances, which were used in this study, were isolated from a sample of Slovak alginite based on the procedure of the International Humic Substances Society (IHSS). The following analytical techniques were selected for the characterization of isolated humic substances: thermogravimetric and elemental analysis, molecular absorption spectroscopy (UV/Vis), Fourier transform infrared spectroscopy (FTIR) and steady-state fluorescence spectroscopy. Each organic fraction of humic substances were characterized by molecular absorption spectroscopy (UV/Vis) and steady-state fluorescence spectroscopy. Using steady-state fluorescence spectroscopy, humic substances were found to be composed of fluorophores of humic and non-humic (protein) character. Organic fractions corresponding to the humic fluorophores were characterized by a higher content of oxygen substituents on the aromatic nukleus, a higher degree of aromaticity and also a higher molecular weight. The aim of this diploma thesis was to design and optimize the process of organic matter fractionation for the purpose of detailed understanding of the structure and properties of humic substances, which were isolated from the sedimentary rock alginite. Based on this, the practical applicability of the thin layer chromatography method to significantly reduce the molecular heterogenity of the studied humic substances was evaluated.
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Study of decomposition of organic matter in soil using the method of "tea bags"
Lišková, Kateřina ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
The main aim of this master thesis was to introduce an optimal method which could be used for study of a decompostion of an organic matter in a soil. For this purpose was chosen based on a literaly review so-called tea bag method. With regard to the completeness of the work, a physico-chemical characterization of the soil environment and HS isolated from it was also performed. The degraded organic material was then further characterized using thermogravimetric analysis, elemental analysis, FT-IR spectroscopy, and the total content of water-extractable polyphenolic substances in the samples was also determined.
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Utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of PHA producing bacteria
Beránková, Barbora ; Enev, Vojtěch (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the study of the utilization of Raman spectroscopy and Raman tweezers for analysis and isolation of polyhydroxyalkanoates (PHA) producing bacteria. Using gas chromatography with FID detection, we determined the polyhydroxybutyrate (P(3HB)) content of the PHA biomass of bacterial strains Burkholderia cepacia, Halomonas halophila, Cupriavidus necator H16 and its mutant strain Cupriavidus necator H16/PHB-4 and Lactobacillus delbrueckii, which is not a producer of polyhydroxyalkanoates but this bactrea was selected as representative of Gram-positive bacteria. Subsequently, thanks to Raman microspectroscopy, Raman tweezers and FT-IR spectrometer in combination with Raman FT-module, we were able to confirm or disprove the presence of P(3HB) in bacteria. Furthermore, the thesis describes Cupriavidus necator H16, which is a model organism for the production of P(3HB), and his mutant strain Cupriavidus necator H16/PHB-4. The bacterial strain Cupriavidus necator H16 was cultivated in a production mineral medium of various nitrogen contents, while cultivation was also carried out in liquid Nutrient Broth. By this cultivation we were able to reach various P(3HB) content in bacterial biomass, the spectra were subsequently compared with the spectrum of the bacterial strain Cupriavidus necator H16/PHB-4. Raman spectroscopy is well used to characterize the composition of individual bacterial cells, is a fast, versatile, and virtually non-invasive tool for studying cells.
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Preparation and characterization of magnetic nanoparticles modified by surfactants
Solnička, Ondřej ; Másilko, Jiří (referee) ; Enev, Vojtěch (advisor)
Theme of this bachelors thesis was preparation and characterization of iron(II, III) oxide nanoparticles. Those nanoparticles were modified by surfactants. The surfactants which were used for modifiation were CTAB, TTAB and Septonex. Prepared and modified nanoparticles were taken for characterization by using methods of elemental analysis, thermogravimetry, dynamic light scattering and transmission electron microscopy (TEM). Results from each measurement shows that nanoparticles modified by CTAB had on average 85.9 nm in diameter, TTAB size was on average 108.3 nm and the last nanoparticles with Septonex had 246.6 nm in diameter on average. Prepared modified nanoparticles except the Septonex ones were stable enough to not aggregate. Septonex modified nanoparticles had greater tendenty to aggregate.
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Characterization of humic substances isolated from natural waste treated by vermicomposting process
Marková, Kamila ; Doskočil, Leoš (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with the study of humic substances isolated from vermicompost natural waste through spectrometric methods. The aim of this thesis is to study physicochemical properties of the humic substances through modern instrumental techniques such as molecular absorption spectroscopy in the ultraviolet and visible regions of electromagnetic radiation (UV/Vis), infrared spectroscopy with Fourier transformationn (FTIR), elemental analysis (EA), thermogravimetric analysis (TGA) and inductively coupled plasma emission (ICP OES). A research focused on basic information about the humic substances was developed in the theoretical part. A description about their distribution or structure was made and also their utilization in medicine, industry or ecology. Then, methods, which are used for study of the humic substances, were described as well. An essential part of the thesis was isolation of humic and fulvic acid from the vermicompost natural waste. Absorption coefficients were calculated from the measured UV/VIS spectrum which served to following characterization of HK and FK. FTIR spectrum was used to determination of functional groups of studied HL. An area of biogenic elements was specified using the elementary analysis. Total amount of studied trace elements was determined with with the help of ICP-OES.
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Stability of soil organic matter and humic substances
Nováková, Šárka ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on changes of stability in organic matter by extraction in different agents. Two soils of a different type and isolated humic acids were used for stability determination. Extraction agents were selected usually used for soil metal extraction, and a changes in the structure of the organic matter was observed. Samples were characterized using FTIR analysis and elemental analysis, the extracts were measured by UV-VIS spectroscopy, absorption ratios E2/E3, E4/E6 were discovered, dynamic light scattering were determined for particle size distributions. Next part of the thesis was the assessment of the change of thermal stability using thermogravimetric analysis and differential scanning calorimetry, degradation temperatures of the extracted samples were discovered and compared with the original samples.
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Analytical methods for determination of polyhydroxyalcanoates content in bacterial cells
Černayová, Diana ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with methods that are used for determination of polyhydroxyalkanoates (PHA) in cells of bacteria Cupriavidus necator H16. To the applied methods belong Fourier transform infrared spectroscopy, Raman spectoscopy, turbidimetry and thermal analysis (thermogravimetric analysis and differential scanning calorimetry). The results of each method were compared to amount of PHA determinated by gas chromatography. Fourier transform infrared spectroscopy and Raman spectroscopy revealed a linear relation between ratio of characteristic peaks and amount of PHA. FTIR enabled to determine not only the quantitative amount of PHA, but the quality of the sample (cristallinity, amorphous state) as well. Another method was turbidimetry, which has shown correlation between dispersion of UV-VIS light to amount of PHA in bacterial cells. Thermogravimetric analysis was the most effective technique for determination of PHA. The dependence of weight loss of PHA on its content (found by gas chromatography) was determined with the highest accuracy to gas chromatography. Tha last method- DSC was not alternative replacement for quantitative PHA determination. However, DSC indicated crystalline and amorphous state of the polymer.
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Decomposition and stability of organic matter in soil
Tabaková, Eva ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
In the soil, the plant material is decomposed by several factors. In the process, one part of the carbon returns to the atmosphere as carbon dioxide, whereas another part is stabilised in the soil. The aim of this study is decomposition and stability of organic matter in soil using a simple and innovative TBI method. Through this method, we examined the weight change after the incubation period of 90 days, where biomass of green tea was degraded in cambodia soil. Tea bags have provided us with valuable information on the decomposition and amount of carbon in the soil, because the biomass itself is of organic origin. This information is based on the fact that the soil and the decomposition processes have a direct impact on the change in climatic conditions. Thanks to further analytical methods, elemental analysis, thermogravimetric analysis and infrared spectroscopy with Furier transformation, was found indispensable information about tea composition.
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Study and characterization of organic substances in a biochar sample
Vojáčková, Beáta ; Kalina, Michal (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis characterizes biochar from a physico-chemical point of view. The theoretical part deals with biochar as a soil conditioner, its properties, use, production, and last but not least, effect of its sorroundings. For better characterization of organic and inorganic matter a phosphate buffer was used. This buffer ensures their specific extraction due to a neutral pH. The second path is to use rainwater, which simulates the condition of the soil environment. In the experimental part are discussed both; purified buffer-extracted samples and rainwater samples, which were studied by thermogravimetric analysis (TGA), elemental analysis (EA) and by infrared spectroscopy with Fouier transform (FTIR-ATR). Conductivity and pH were also measured. Moisture and ash content, which represent the inorganic non-combustible fraction, were determined using thermogravimetry. The extraction yields were converted to ashless wt. % based on these values. Results of EA provided us with information on the content of biogenic elements and basic physico-chemical characteristics of biochar. In contrast, the FTIR method defined the presence of individual functional groups and specific constitutive units, which are present in the extracts. This information allows us to better understand the environmental impact of biochar on the soil ecosystem.
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