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Quantification of the stabilizing effects of cyclodextrins on volatile biocides using spectral methods
Konovalova, Olga ; Jindřich, Jindřich (advisor) ; Smrček, Stanislav (referee)
This bachelor's thesis deals with monitoring the stability of chlorine dioxide of native and methylated cyclodextrins in the presence of hydrogenating agents. It is believed that using cyclodextrins and carboxymethylcellulose can improve the stability of chlorine dioxide and slow its release from the solution. UV spectroscopy was used to monitor any changes in absorbance over time and to determine the concentration of chlorine dioxide in the solution. When the rate of chlorine dioxide loss from solution was monitored, it was found that the presence of native and permethylated cyclodextrins slowed the loss of chlorine dioxide from solution, with the slowest decomposition observed in the presence of permethylated cyclodextrin. The addition of carboxymethylcellulose to the chlorine dioxide solution slows the rate of chlorine dioxide loss from the open vial the most, by almost three times, compared to ClO2 itself. This study's results can help optimize chlorine dioxide product formulation for various applications and contribute to the development of more stable and effective chlorine dioxide- based products that can be used to control or eliminate harmful microorganisms in different environments. Key words: chlorine dioxide, CDS, cyclodextrins, carboxymethylcellulose, biocides, UV-Vis...
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The fate of phosphorus in root wastewater treatment plants
Veselá, Klára ; Sobotníková, Jana (advisor) ; Nováková, Eliška (referee)
This bachelor's thesis deals with the determination of phosphorus in constructed wetlands. Phosphorus in wastewater must be eliminated effectively because there is a government regulation that permits maximal permissible concentration of phosphorus on the exit of wastewater treatment plants. Increased concentration in water leads to eutrophication, which causes the death of aquatic animals and plants. The aim of this bachelor's thesis is the validation of an easy and functional method for the determination of phosphorus in the water matrix. This method uses a complex with malachite green. The next aim was the determination of phosphate in the samples from model constructed wetlands. It's possible to make conclusions about the efficiency of model constructed wetlands out of this. For the determination UV-VIS spectrophotometry was used. The measured absorbance was recalculated to a concentration of phosphorus and after that to the concentration of phosphate. During the validation calibration, accuracy measurement, repeatability measurement, and measurement of absorbance dependence on time were performed. Sensitivity (by comparing the malachite green method with the normed method using phosphomolybdate blue), linearity, trueness, robustness, the limit of detection, and the limit of quantification were...
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Study of surface water quality in the Ivančice area
Jonášová, Simona ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
Selected physical and chemical water quality parameters were measured at four sampling localities on the Jihlava River. Using UV-VIS spectrophotometry, inorganic forms of nitrogen, chlorides, total phosphorus and CODCr were determined. BOD5 was determined by the dilution method. Na+, K+ and Ca2+ ions, whose concentrations ranged from 5,75–108 mgl 1, were measured by flame emission photometry. Selected metals (Cu, Ni, Pb, Zn, Hg, Cr, Fe, Mn) were determined in water by the ET-AAS method. Decomposed sediments were determined by the FAAS method. Concentrations of Cr, Cu, Pb and Ni in water were in the range of 0,05–2,84 gl1. Metal concentrations in sediments ranged from 0,02–293 mgkg1, where nickel concentrations were above the limit. The occurrence of iron and manganese is due to the geological subsoil. For the other elements, anthropogenic source is assumed. From the measured data, the water quality is slightly variable in this locality and is classified as fourth or fifth class, i.e. as highly polluted water.
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Incorporation of low molecular weight and high molecular weight substances into vesicular systems
Geistová, Karolína ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This master´s thesis deals with the study of the incorporation of low and high molecular weight substances into liposomal systems. The aim of the work was to determine the encapsulation efficiency (EE) of the active substance and the influence of individual components of the liposomal system on EE. Liposomes were prepared from dipalmitoylphosphatidylcholine. They were stabilized by cholesteroland and phosphatidic acid was added to give a negative charge. Stealth properties gain the binding of polyethylene glycol and other trimethyl chitosan we enabled the entry of liposomes into the bloodstream by the paracellular pathway. Vitamin C and the enzyme bromelain were used for incorporation into liposomes. UV-VIS spectrophotometry was used to determine the encapsulation efficiency of liposomes prepared by combining the individual components. It has been suggested that vitamin C and the enzyme can be incorporated into liposomes, but an enzyme with a higher EE. Furthermore, phosphatidic acid and trimethyl chitosan have been found to affect EE, which increases the EE of vitamin C and decreases the EE of the enzyme.
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Caffeine degradation by high frequency discharge in solutions
Korečková, Svatava ; Mravcová, Ludmila (referee) ; Kozáková, Zdenka (advisor)
The bachelor thesis deals with the degradation of caffeine in solutions by a high frequency discharge generated directly in the solution. The influence of experimental conditions such as the initial pH and conductivity of the solution, caffeine concentration or electrode geometry was studied. The prepared caffeine solutions had a concentration of 10–100 ppm and their initial pH was adjusted with electrolytes (NaCl, Na3PO4, Na2HPO4 and NaH2PO4). All experiments were performed in a batch plasma reactor consisting of a 400 ml beaker and two electrodes. UV-VIS spectrophotometry was used to determine the amount of degraded caffeine. It was found that the experimental conditions (electrical conductivity, power, type of electrode used, electrolyte used) have an effect on the degradation of caffeine. The most suitable electrolyte appears to be NaCl and the initial specific electrical conductivity set in the range of 400–500 S·cm–1.
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Solubilization in catanionic surfactant systems
Konečná, Anna ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the solubilization of hydrophobic dyes in systems of positively charged catanionic vesicles. The aim of the work was to determine their solubilization capacity. Vesicular systems were prepared from oppositely charged surfactants CTAB and SDS. To increase the stability of the vesicles, cholesterol and the positively charged double-chain surfactant DODAC were added to their structure. DODAC also gave the system a positive charge. To determine the solubilization capacity, the dyes 1-Naphthol, Sudan Red G and Oil Red O were used. For sample preparation two methods were used, spontaneous and direct solubilization. The measurement was performed after 1, 2, 3 and 7 days from the preparation of the samples by UV-VIS spectrophotometry. The solubilization capacity was determined from the measured absorbance by calculation from the calibration curves. The results indicate that direct solubilization is slightly more effective than spontaneous solubilization. Of the selected dyes, 1-Naphthol is the substance with the smallest molecule, and therefore it seems to be 100% solubilized in the vesicle system.
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Optimization of extraction of pigments from yeast and algae cells
Šimanský, Samuel ; Mikulíková, Renata (referee) ; Márová, Ivana (advisor)
The presented diploma thesis deals with the extraction and storage stability of lipophilic pigments produced by selected strains of yeasts and algae. In this thesis, there was studied the influence of the selected solvents on the efficiency of extraction, as well as the effect of ambient temperature on the stability of the pigments during storage. The work is divided into two main parts, theoretical and practical part. In the theoretical part knowledge about algae, yeasts and their cultivation parameters is summarized. Furthermore, some information regarding the selected lipid metabolites, their properties and possibilities of application in various branches of industry is mentioned. The practical part deals with the preparation of extracts and stability tests. Extracts were prepared from selected biomass samples in solvents suitable for applications in food industry or cosmetics (ethanol and hexane). Subsequently, the long-term stability tests lasting 4 months and short-term stability tests lasting a total of 28 days were performed on these extracts. The pigments were determined by HPLC and spectrophotometrically, the fatty acid content was determined by GC. For the extraction of pigments from biomass, in the most cases ethanol appears to be the optimal solvent. However, for lipid extraction from biomass, hexane appears to be the optimal solvent for a significant number of samples. In most samples, storage in the freezer showed the most favourable effect on pigment stability, but some samples showed comparable stability even when stored in the refrigerator.
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Influence of dispersion parameters on formation of vesicular systems
Vajcíková, Katarína ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
The work describes a method for the preparation of catanionic vesicular systems using the method of ultrasonic dispersion in order to find the most suitable parameters for the preparation of a system with long–term physical stability. The parameters compared were the amplitude of the ultrasonic wave, the energy used for dispersion, and the volume of deionized water used to prepare a system consisting of the negatively charged surfactant sodium dodecyl sulfate and the positively charged surfactant hexadecyltrimethylammonium bromide. To increase stability and provide a positive charge, the surfactant dimethyldioctadecylammonium chloride was used and cholesterol was also added to increase stability. The individual systems were compared over time because of their size, zeta potential and turbidity of the solution. Particle size and polydispersity coefficient were measurement by the dynamic light scattering method. The zeta potential was determined by electrophoretic light scattering, and the turbidity was monitored by UV-VIS spectrophotometry based on the measurement of turbidity. The results present the most suitable parameters of ultrasonic dispersion using Bandelin SONOPULS UW 3200. The use of these parameters shows the emergence of systems with long–term physical stability, which means that they can be used for other applications.
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Study of plasma effects on quinine solutions
Procházková, Michaela ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
This diploma thesis focuses on quinine solutions and quality of these solutions after applying plasma discharge. These electric discharges can be used to destroy some substances from the water. The theoretical part is focused on description of electric discharges in liquids and on the properties of quinine. In the experimental part, the properties of quinine solutions containing different electrolytes were analysed by UV-VIS spectrophotometer and fluorescence spectroscopy. Two different types of configurations of plasma discharges in liquids were used. Solutions were compared on the base of different concentration of quinine, different electrolytes, different configurations of plasma discharges and pH values of the solutions. Furthermore, the experimental work focuses on quinine solutions with the sodium nitrate. The time instability of the solutions was analysed. Also, the influence of the solution age and different types of the plasma discharge on the excitation and emission spectra of quinine were investigated.
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Bioactive compounds of fennel
Nentvichová, Aneta ; Vespalcová, Milena (referee) ; Veselá, Mária (advisor)
The aim of this bachelor thesis is to study the bioactive substances contained in fennel, to determine the content of polyphenols, flavonoids and to investigate the antioxidant and antimicrobial activity in aqueous and ethanol extracts of fennel. The theoretical part discusses the characteristics of fennel, its classification in the system, its use and especially the bioactive substances contained in it. The experimental part is divided into two sections, where the first part focuses on spectrophotometric determination of polyphenols, flavonoids and antioxidant activities. In the second part the antimicrobial effects of prepared extracts of fennel were examined. Two microorganisms Serratia marcescens and Bacillus cereus were exposed to the said extracts. Antioxidant activity and relatively high content of polyphenols and flavonoids were found in the extracts in the first experimental part. The second experimental part proved that the antimicrobial effect of the extracts was very low, in most cases almost negligible. Ethanol extracts showed higher antimicrobial activity, while hot water extracts found to support the growth of Bacillus cereus.
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