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Use of capillary electrophoresis to determine a selected group of flavonoids
Tran Xuan, Tiep ; Mravcová, Ludmila (referee) ; Řezáčová, Veronika (advisor)
In recent years, the use of natural medicinal properties of plants has again come to the forefront of interest of the public. Because of their therapeutic properties, these plants are commonly used in alternative treatments for minor ailments. This thesis deals with the determination of polyphenolic acids in extracts from aronia, echinacea, tetradenia and centella. One of the aims of the thesis was to compare the amount of polyphenolic acids in individual plants with their antioxidant properties. The theoretical part includes a general introduction to flavonoids, introduction to polyphenolic acids, introduction to the principles of capillary zone electrophoresis and a summary of selected foreign studies for the determination of flavonoids. An important chapter of the theoretical part is a description of individual plants with an explanation of their possible therapeutic use. The experimental part is devoted to the process of optimization of electrophoretic determination of selected polyphenolic acids and evaluation of their content. It was found that in the extracts six representatives of polyphenolic acids occur in minimal amounts, often below the limit of quantification or detection of the method.
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Use of various extraction techniques for the analysis of biochar extracts
Jakubčeková, Kristína ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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Criteria for drinking water for breeding medical leeches
Krýslová, Jana ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of breeding leeches with regard to the quality of the water in which it is bred. It focuses on the comparison of individual criteria of drinking water taken from different sources of drinking water (Letovice, Brno and the surroundings of Brno). The sources of these waters are from Vír and Březová, or they are mixed in a certain ratio. Selected indicators of drinking water quality were measured in individual water samples using UV-VIS spectrometry, flame photometry, turbidimetry and volumetric methods. Rajec baby water, purchased from the retail network, was selected as a comparative sample. From the obtained data it was found that the values of water hardness have the greatest influence on the success of leech breeding. It is generally known that too hard water does not benefit the leech, and therefore it dies. For the other determined parameters, it was not possible to prove whether they have a significant influence on the breeding of leeches and its death.
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Identification of contamination sources in the PET recycling
Snopková, Martina ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
This paper deals with the identification of plastic contaminants in polyethylene terephthalate (PET) flakes obtained by mechanical recycling of PET bottles. The presence of contaminants in recycled material is undesirable and it is necessary to implement and optimize technologies to separate them. For improving the effectiveness of separation, it is crucial to determine the material of the contaminant. Papers that are focusing on the contaminant analysis in PET flakes are sporadic. In practice, there are not enough sources for enhancing the effectiveness of separation based on the material of the contaminant. The goal of this thesis is to provide missing information about the materials of plastic impurities. Obtained findings will contribute to efficiency improvement of contaminant separation and production of better-quality recycled material. For contaminant analysis, Fourier-transform infrared spectroscopy with attenuated total reflection technique (FTIR-ATR) was used. The samples were analyzed using an ALPHA II device with an ALPHA-P module with the diamond crystal. It was found out that the most frequented contaminants are polymers polystyrene (PS) and its modifications, polyethylene terephthalate glycol (PETG), PET mixed with other polymers or additives, polypropylene (PP), polyamide (PA), styrene acrylonitrile (SAN) and polyvinylchloride (PVC). Based on these results, the recommendations for enhancing the efficiency of separation were developed. Some of the results pointed out the actual problems that complicate PET bottle recycling.
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Study of the interaction of selected pharmaceuticals with microplastics
Ioani, Aldina ; Řezáčová, Veronika (referee) ; Doležalová Weissmannová, Helena (advisor)
The bachelor thesis aims to study the interaction of selected pharmaceuticals from the group of analgesics and antibiotics with microplastics. The analysis was conducted in the mid-infrared region, which is used to identify chemical structure of the substances. Fourier transform infrared spectroscopy was used as an analytical method. The samples were subjected to technique attenuated total reflection. Ibuprofen and trimethoprim were chosen as analytes due to their common usage in the population. Sorption of pharmaceuticals was undergoing on polyhydroxybutyrate, which is a kind of biodegradable plastics and polyethene terephthalate, which is synthetic. Measured results showed that for the study of interaction with pharmaceuticals, it is more suitable to use biodegradable plastic polyhydroxybutyrate than polyethene terephthalate because of its better results. Infrared spectra output is very influenced by a selection of a solvent.
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Ecotoxicological evaluation of selected psychotropic drugs
Hricová, Nikoleta ; Řezáčová, Veronika (referee) ; Zlámalová Gargošová, Helena (advisor)
This bachelor thesis done by literary research is about the issue of the occurence of psychopharmacs in the enviroment. Psychopharmacs such as antidepressants, anxiolytics, hypnotics, sedatives etc. belong to one of the most sold drugs around the world. The consumption of psychopharmacs is concerning and growing. Therofore their occurence in nature is also growing, which can negatively affect the ecosystems. Many studies confirmed the persistency of psychopharmacs in nature, their following bioaccumulation and ecotoxicity for the representatives of each ecosystem. This bachelor thesis describes possible ways of the drug’s intersection (penetration) in nature, the metabolism of psychopharmacs in the human body and the effectivity of their elimination in sewage tanks. This work also focuses on the occurence, stability, degradability and persistency of psychopharmacs in aquatic and in terrestrial enviroment. The consideration of risks in the occurence of psychopharmacs for the representatives of each ecosystems was processed by many ecotoxicological studies, which point out the danger of these substances. Based on this acquired knowledge, in the conclusion of this work, there was drafted a battery of ecotoxicological tests for the estimated effects of psychopharmacs.
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Modern herbs in the food industry
Adamczyková, Michaela ; Řezáčová, Veronika (referee) ; Vítová, Eva (advisor)
The bachelor thesis deals with the issue of volatile (aromatic) compounds of Plectranthus spp. and Echinacea purpurea. The theoretical part focuses on the general characteristics of the above mentioned herbs, the content of their bioactive and volatile compounds, and on their importance as well as on their potential use in the food industry. Using the HS-SPME-GC-MS method, the volatile compounds of the herbs and extracts prepared from them were identified and quantified in the experimental part. A total of 11 volatile compounds were found in all the samples. The most frequent one in the sample of a fresh Plectranthus was 3-carene (13,78%) as well as in the sample of dried Plectranthus (14,85%). However, in the Plectranthus extract it was -selinene (17,84%). As for Echinacea, it is germacrene D (18,64%) in the sample of a fresh one, camphor (58,46%) in the one of dried Echinacea and -copaene (20,42%) in its extract.
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Study of selected antibiotics sorption on polyhydroxybutyrate
Amrichová, Anna ; Doležalová Weissmannová, Helena (referee) ; Řezáčová, Veronika (advisor)
The bachelor thesis deals with the issue of sorption of antibiotics on microplastics. Antibiotics and microplastics are now a highly studied topic, due to the positive and negative properties. Antibiotics with groups of sulfonamides and quinolones were selected for the experiment. From sulfonamides, sulfamethoxazole and trimethoprim were selected, and from the quinolones, enrofloxacin and ciprofloxacin, which have already been the impetus for some microplastic studies. Biodegradable polyhydroxybutyrate was used as the microplastic. Two experiments were performed in the laboratory. The first aimed to monitor the time dependence of antibiotic sorption on polyhydroxybutyrate, the second the concentration. The concentration dependence was subsequently evaluated using the Freundlich and Langmuir isotherms. The method of liquid chromatography with mass spectrometry was used for analyzes.
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The study of PET bottles in terms of the content of risk elements
Kryštofová, Petra ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the issue of PET bottles in terms of the possible content of risk elements. The contents of antimony, copper and lead were determined in the PET packaging material and in the beverages contained in the bottles. A total of 15 samples of bottled still and infant water available in the Czech sales network were analyzed. The PET material was decomposed in an acidic medium under the action of microwave radiation under optimized conditions. Atomic absorption spectrometric methods with flame or graphite cuvette atomization were used to determine selected risk elements based on the predicted analyte concentrations. In the PET packaging material, 159.35 to 265.68 mgkg-1 of antimony were determined, the determined values of lead concentration were in the range of 10.96-20.23 mg·kg-1 and the copper concentration in the range of 0.11-7,52 mg·kg-1. In bottled water and in bottled infant water, antimony was identified only in samples labeled 6a, 8a, 9a and 15a, all lead concentrations were measured below LODPb, copper was determined only in samples 2a, 6a and 8a. In none of the samples did the concentrations given by the valid legislation be exceeded. The limits of these metals are not set in legislation in the packaging materials, only specific migration limits and they have not been exceeded. However, the high concentration of antimony in PET poses a potential risk of contamination of the contents of these packages.
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Determination of volatile substances of natural extracts intended for cosmetic application
Paskevych, Olha ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
Tato bakalářská práce je soustředěná na zkoumaní přírodních komerčně dostupných extraktů, které se používají do přírodní kosmetiky. Literární rešerše byla zaměřena na téma obsahu těkavých látek v přírodních extraktech používaných v kosmetice, jejich charakterizace a možnosti stanovení, problematika výskytu alergenů v přírodní kosmetice. Na základě tohoto přehledu byla navržena optimální metoda pro analýzu vzorků přírodních extraktů s přihlédnutím k dostupné analytické instrumentaci. Následující výtažky byly studovány se zaměřením na kvalitativní stanovení: mandle, aloe vera, hřebíček, Etiopská káva, zázvor, cibule.
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