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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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Analysis of organic substances present in biochar
Bača, Ondřej ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This master's thesis deals with the analysis of organic substances, which are present in biochar. Biochar contains a number of organic compounds, that can be toxic and also carcinogenic to living organisms. In order for biochar to be used to improve soil quality or to be used for other applications, its safety must be declared by European or international certifications. Relevant European and international standards have been created for the determination of organic substances, that could be present in biochar. The theoretical part of the thesis was focused on selected organic substances, the process of pyrolysis and thermochemolysis, biochar characterisation and the used analytical methods. The experimental part of the thesis consisted of extraction with toluene and after that the determination of concentration of the 38 polycyclic aromatic hydrocarbons was performed. Qualitative analysis was performed by two-dimensional gas chromatography. Biochar samples were also subjected to thermochemolysis method and then they were analysed on GC-MS again. In both analytical methods, a large number of substances from groups such as PAHs, carboxylic acids, amines, substituted naphthalenes etc. was found, as well as smaller number of eg. polychlorinated biphenyls.
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Analysis of substances released from composite dental material
Fučík, Jan ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This master's thesis deals with a present problem of alternative dental fillings, which should replace amalgam fillings. Although there are health concerns about these alternative materials, especially resin composite fillings raise concerns, because they release potentionally harmful substances into the oral cavity. Accordingly even this medical device subjects various tests before releasing to the commercial market and one of these tests was carried out according to ČSN EN ISO 10993 and available scientific literature in the experimental part of this thesis. The amalgam controversy, substances used for manufacturing of resin dental fillings and analytical methods are described in the theoretical part of the thesis. In the experimental part of the thesis, 30 days long cumulative extraction experiments were carried out into various extraction mediums in order to assess suitability of new dental resin filling from ADM, a.s. by comparison with commercially available dental material from company GC EUROPE N.V. These samples were analysed by LC-MS and the amount of eluted substances from dental composites to extraction medium was quantified.
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Fate of microplastics in soil
Kameníková, Eliška ; Řezáčová, Veronika (referee) ; Kučerík, Jiří (advisor)
The problems with microplastics, small plastic particles contaminating the environment, is a subject of heated discussions today. It has been recognized that the microplastics are not inert, but instead they have an impact on all enviromnental compartments. There are studies describing the negative effects of microplastics, for example on fauna and flora or on human health, but the effects on soil quality have not been sufficiently described. The aim of this thesis was to assess the short and medium term effects that microplastics could have on the soil. In this work, a series of experiments were performed to elucidate the fate of microplastics in the soil. Changes in soil organic matter thermal properties, soil respiration, amount of water and soil aggregation depending on the incubation time were monitored. Three types of agricultural land (chernozem, cambisol and phaeozem), which were contaminated with different concentrations od PET and tyre rubber, were tested. The results confirmed the specific effects of microplastics on soil properties, which were observed in non-incubated samples (i.e. at the time of incubation 0 months), microplastics did not behave inertly in the soil and affected, for example, soil properties, texture and respiration.
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Exercise of copyright by a person other than the author (of author's heirs)
Řezáčová, Veronika ; Císařová, Zuzana (advisor) ; Žikovská, Petra (referee)
of the diploma thesis The exercise of copyright by a person other than the author (heir of the author) The diploma thesis The exercise of copyright by a person other than the author (heir of the author) deals with the Czech legal framework of a work created by an employee and a collective work in terms of their specific position in the Czech legal framework resulting from the legal restriction of the exercise of the exclusive economic rights of an author and partly the exclusive moral rights of an author of a work within broader context with the German legal framework of a work created by an employee and a collective work, and with the legal framework copyright of the United States of America, especially a work created by employee under the legal doctrine "Work made for hire" and a collective work. The aim of the diploma thesis is to anchor the Czech legislation in a broader sense by including the conservative German legislation based on the continental legal system and by including the legislation of the United States of America symptomatic of the common legal system. The first chapter, based on the conceptual framework of the continental and the common legal system, incorporates the concept of the authorship, the position of the author and the author's work in the Czech Republic, Germany and the...
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Study of microplastic sorption properties
Hlaváčková, Hana ; Kučerík, Jiří (referee) ; Řezáčová, Veronika (advisor)
There is currently an effort to replace conventional plastics with biodegradable products that will have the ability to replace these substances. One of the possible biodegradable felt, which is currently being studied in detail, is also poly (3-hydroxybutyrate), which is produced by bacteria. This bachelor thesis deals with the sorption of selected substances on poly(3-hydroxybutyrate) microparticles. Substances whose contamination of water sources is a significant problem today have been selected for this work. Specifically, the sorption of the nonsteroidal anti-inflammatory substance ibuprofen, the triazole fungicide tebuconazole and the most common drug caffeine on PHB particles, which fall in the size of the microplastic group, were studied. The method of liquid chromatography with mass detection was used for analyzes.
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Use of liquid chromatography to analyze caffeine solutions exposed to plasma
Brabcová, Kristýna ; Řezáčová, Veronika (referee) ; Mravcová, Ludmila (advisor)
This thesis deals with the current problem of increasing concentration of caffeine in water that is connected with caffeine consumption among people. This problem is not that urgent becusase the concentration is not high and for human is not so harmful. The bigger populaton is, the more caffeine people consume and the amount of caffeine in wastewater rises. This fact could be considered as a future problem. An appropriate method effective for elimination of harmful substances are advanced oxidation processes (AOP). Theoretical part describes purine alkaloids with detail desctription of caffeine. Plasma was chosen as a method for caffeine degradation and there are some facts described. There is a chapter about appropriate analytical methods. The samples were picked after periodical time intervals. These samples were analyzed by UHPLC. The results were compared with study dealing with this theme.
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Hair as a bioindicator of contamination of risk metals
Zmijová, Marie ; Řezáčová, Veronika (referee) ; Zlámalová Gargošová, Helena (advisor)
The use of hair as a bioindicator of environmental contamination by risk elements is becoming more and more common. This bachelor thesis deals with the use of this matrix for analysis using the voltammetric method. It focuses on the optimization of the method for determining the concentration of cadmium, copper, lead and zinc in real hair samples and monitors the effects on the incorporation of these elements into the hair fiber. The presence of zinc and copper was confirmed in all samples analyzed. Cadmium could only be quantified in one sample. The effect of gender and age on the concentration of elements has not been demonstrated. Concentration of lead has been linked to smoking, with higher concentrations found in smoker’s hair than in non-smoker’s.
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