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Determination of sweeteners and preservatives in energy drinks by HPLC
Zídková, Anežka ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This master´s thesis is focused on simultaneous determination of sweeteners and preservatives in energy drinks by liquid chromatography coupled with DAD and ELSD detection. The method was optimized for determination of aspartame, acesulfame K, saccharin, sucralose, steviol glycosides, benzoic acid and sorbic acid. Analyses were carried out on the Poroshell 120 EC-C18 column (4.6 x 150 mm, 2.7 m, Agilent) using mixture of methanol, acetone and water with formic acid and trimethylamine as a gradient mobile phase at a flow rate 0,5 mL•min-1. Validation parameters were determined (limit of detection, limit of quantification, repeatability and recovery). The validated method was applied on real samples.
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Photoelectrochemical oxidation of aqueous polutants
Pachovská, Martina ; Králová, Marcela (referee) ; Dzik, Petr (advisor)
The thesis is focused on the use of photochemical reactions and their applications for removal of aqueous pollutants such as organic acids. For evaluation of photochemical oxidation was used benzoic acid as model pollutant. Decreasing of concentration and oxidation products were monitored by UV-VIS spectrometry. The formation of oxidation products was observed by fluorescence measurement. Subsequently the stability and properties of model aqueous pollutant and electrochemical properties of used photoelectric cells were studied. The aim was to determine the appropriate reaction conditions and limits of degradation reaction.
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Photocatalytic activity of hybrid titanium dioxide layers treated by plasma
Koukolová, Anna ; Králová, Marcela (referee) ; Veselý, Michal (advisor)
The bachelor thesis deals with photocatalytic activity of thin layer of titanium dioxide deposited onto PET flexible foil treated by plasma. Photocatalytic activity is measured by two different methods, degradation of dye Acid Orange 7 and benzoic acid. Possible model compounds for evaluation of photocatalytic activity as well as deposition techniques for preparing thin layers of photocatalyst were discuss in the theoretical part. Changes of photocatalytic activity were found insignificant with plasma treatment. Evaluation used Acid Orange 7 is suitable. Unlike method with benzoic acid was discovered inappropriate for measuring of photocatalytic activity for photocatalyst deposited onto PET foil.
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The influence of material composition and spatial arrangement on the properties of photoelectrochemical cells
Pachovská, Martina ; Krystyník, Pavel (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with photoelectrochemical cells containing photoactive titanium dioxide anode and their use for photocatalytic degradation of organic compound from water solutions. The electrical properties of the produced photoelectrochemical cells were determined by the use of voltamperometric characteristics, the oxidation ability of the cells was monitored by measuring the fluorescence of the oxidative intermediates. To study these reactions, benzoic acid was used as the fluorescence probe for OH˙ radicals. The aim of the study was to study the influence of material composition and spatial arrangement of the cathode and the relationship between irradiation, current and rate of electrode processes.
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Determination of sweeteners and preservatives in energy drinks by HPLC
Zídková, Anežka ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This master´s thesis is focused on simultaneous determination of sweeteners and preservatives in energy drinks by liquid chromatography coupled with DAD and ELSD detection. The method was optimized for determination of aspartame, acesulfame K, saccharin, sucralose, steviol glycosides, benzoic acid and sorbic acid. Analyses were carried out on the Poroshell 120 EC-C18 column (4.6 x 150 mm, 2.7 m, Agilent) using mixture of methanol, acetone and water with formic acid and trimethylamine as a gradient mobile phase at a flow rate 0,5 mL•min-1. Validation parameters were determined (limit of detection, limit of quantification, repeatability and recovery). The validated method was applied on real samples.
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Photocatalytic activity of hybrid titanium dioxide layers treated by plasma
Koukolová, Anna ; Králová, Marcela (referee) ; Veselý, Michal (advisor)
The bachelor thesis deals with photocatalytic activity of thin layer of titanium dioxide deposited onto PET flexible foil treated by plasma. Photocatalytic activity is measured by two different methods, degradation of dye Acid Orange 7 and benzoic acid. Possible model compounds for evaluation of photocatalytic activity as well as deposition techniques for preparing thin layers of photocatalyst were discuss in the theoretical part. Changes of photocatalytic activity were found insignificant with plasma treatment. Evaluation used Acid Orange 7 is suitable. Unlike method with benzoic acid was discovered inappropriate for measuring of photocatalytic activity for photocatalyst deposited onto PET foil.
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The influence of material composition and spatial arrangement on the properties of photoelectrochemical cells
Pachovská, Martina ; Krystyník, Pavel (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with photoelectrochemical cells containing photoactive titanium dioxide anode and their use for photocatalytic degradation of organic compound from water solutions. The electrical properties of the produced photoelectrochemical cells were determined by the use of voltamperometric characteristics, the oxidation ability of the cells was monitored by measuring the fluorescence of the oxidative intermediates. To study these reactions, benzoic acid was used as the fluorescence probe for OH˙ radicals. The aim of the study was to study the influence of material composition and spatial arrangement of the cathode and the relationship between irradiation, current and rate of electrode processes.
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Photoelectrochemical oxidation of aqueous polutants
Pachovská, Martina ; Králová, Marcela (referee) ; Dzik, Petr (advisor)
The thesis is focused on the use of photochemical reactions and their applications for removal of aqueous pollutants such as organic acids. For evaluation of photochemical oxidation was used benzoic acid as model pollutant. Decreasing of concentration and oxidation products were monitored by UV-VIS spectrometry. The formation of oxidation products was observed by fluorescence measurement. Subsequently the stability and properties of model aqueous pollutant and electrochemical properties of used photoelectric cells were studied. The aim was to determine the appropriate reaction conditions and limits of degradation reaction.
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