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Analytical methods for verifying the authenticity of the wine
Flegr, Šimon ; Štursa, Václav (referee) ; Diviš, Pavel (advisor)
This bachelor’s thesis deals with the authenticity of wine, focusing on the authenticity of geographic origin. The theoretical part of this work summarises the main components of wine and their changes during the production proces. Control techniques are introduced, including the ones used by the goverment’s control bureau (SZPI) and other documented methods. Areas recognised for growing wine are described, including the Morava area in Czechia and its imminent adjacent areas in Austria and Slovakia. Experimental part deals with the trace amount analysis of selected elements and phenolic compounds. The element analysis was conducted using mass spectrometry and optical emission spectrometry, whilst the phenolic compounds were separated using high-pressure liquid chromatography with spectrophotometric detection. The results were analysed using discrimination analysis to separate groups with different areas of origin, with the aid of data from former research.
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The selected micronutrients and heavy metals in fruits
Formanová, Kristýna ; Diviš, Pavel (referee) ; Vránová, Dana (advisor)
Today is the food quality a discussed topic not only in the Czech Republic. In this work we focused on micronutrients and heavy metals in strawberries. Strawberries are very attractive fruit consumed by all age groups from children to seniors. These bring not only gustatory pleasure but also positive effects on human organism. Soft fruit structure could contribute to the accumulation of heavy metals, which can be dangerous in certain quantities in terms of acute toxicity or what is more likely in terms of chronic exposure. In the spring - autumn of 2011 samples from the home cultivation of strawberries in the Czech Republic were collected and also samples of fruits that are commonly available in supermarket chains in this period were purchased. The element analysis was performed by the mass spectrometry with inductively coupled plasma, which belongs to a very sensitive method of elements determination.
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Determination of microelements by ICP-OES after extraction by DGT technique
Habartová, Aneta ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This thesis is focused on determination of microelements (Cd, Co, Cu, Fe, Mn, Ni, Pb a Zn) in milk by optical emission spectrometry with inductively coupled plasma (ICP-OES) after extraction by Diffusion Gradients in Thin films technique (DGT) containing Chelex 100 resin gel and agarose diffusion gel. The optimalization of DGT in model metal solutions was verified by recommended basic tests. The performance of the DGT technique in the diluted milk matrix was verified. By DGT technique was determined only Zn in real milk matrix with concentration 3,74 ± 0,02 mg/l. The other microelements in the prepared eluate were at or below the limit of detection of the instrumental method. The obtained results were compared with the analysis of milk after microwave digestion by ICP-OES. However, these results were below the detection limit of the device too, only Zn with concentration 3,91 ± 0,16 mg/l was measured. For the future analysis of the selected microelements in milk by DGT technique, further optimization of the preconcentration technique is required, or use of a more sensitive instrumental method.
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Cycling of selected metals in the environment.
Šebková, Michaela ; Diviš, Pavel (referee) ; Dočekalová, Hana (advisor)
This bachelor thesis deals with a group of selected metals (nickel, zinc, copper, cadmium and lead) in environmental components. It occupies with natural and anthropogenic inputs of metals to the atmosphere, the water und the soil and with their transport among them components. It engages too in a question of a penetration of metals to the biosphere and in their ensuant transport within the biosphere. At each metal is description of its natural sources, chemical and physical properties, inputs in environment, transport within the biosphere and positive and negative effects on living organism is described for each studied metal. The last chapter of this thesis deals with determination of selected metals in environmental components. It discribes procedures of determination from planning over sampling and processing of sample to the final determination of metals by instrumental methods.
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Basic chemical properties of fruits of selected cherry varieties
Chmil, Vojtěch ; Vítová, Eva (referee) ; Diviš, Pavel (advisor)
Diploma thesis is focused on chemical characteristics of nine selected sweet cherry varieties in nine parameters. Total and soluble solids were analyzed with these results 13.07–16.58 % for total and 14.67–19.50 °Brix for soluble solids, ash content 0,31–0,39 %, titratable acidity 5.44–9.91 g of malic acid per 1 kg of fresh cherries and formol number 14.45–23.73 ml of 0.1 M NaOH per 100 g of cherries. Then there were analyzed crude proteins content calculated from total nitrogen content determined by Kjeldahl method with results 0.41–0.68 % of crude proteins. Molecular absorption UV/VIS spectrophotometry was used for determination of total phenolic substances 0.30–0.89 g of gallic acid per 1 kg of cherries and total content of anthocyanins 128–848 mg of cyanidine-3-glucoside in 1 kg of cherries. Saccharides were determined by high performance liquid chromatography (HPLC) with ELSD detector. Content of glucose was 45.45–59.49 g/kg and fructose 46.88–60.01 g/kg. All results are compiled using tables and graphs and discussed. Experimental part of the thesis also describes principles and procedures of every analysis, so it can be reproduced. In theoretical part there is described botanical characteristic of cherry tree (Prunus avium L.), active substances contained in its fruits and their use in food industry. At the end of the theoretical part there is described instrumentation of high-performance liquid chromatography.
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Development of a method for determination of antibiotics in milk using high performance liquid chromatography
Juglová, Zuzana ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
This diploma thesis focuses on optimization and validation of the method for a mixture of tetracycline antibiotics (oxytetracycline, tetracycline) determination using high performance liquid chromatography with a diode array detector (HPLC–DAD). The aim of this thesis was to determine suitability of the system for the determination of these antibiotics in milk. The theoretical part is focused on individual groups of antibiotics and their mechanism of action, resistances and possibilities of use. Next point of this thesis is legislation, which describes permitted amounts of antibiotics in milk. In this study, the HPLC method and validation parameter is described in detail. The experimental part deals with creation and optimization of the method and its validation. Following validation parameters were verified: system suitability, linearity, method accuracy, limit of detection and quantification, robustness. The results obtained indicate mostly suitable ratio of mobile phase of 0,01 M trifluoracetic acid:methanol:acetonitrile = 80:10:10. The wavelength 355 nm was found as the most feasible for this method after evaluating the result. Determination of robustness showed that the method is robust, and the only significant effect on the robustness was observed in column changes.
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Detection methods of energetic materials
Procházka, Michal ; Diviš, Pavel (referee) ; Friedl, Zdeněk (advisor)
A research on current methods of detection of explosives and related materials was made. At first the thesis studies methods of detection and analysis of explosives including chromatographic methods (TLC, GC, HPLC, IC), mass spectrometry and its variations, ion mobility spectrometry and infra-red spectroscopy. Next the attention is placed on detection of explosives in solid phase by X-ray detection, nuclear magnetic and quadrupole resonance and thermal neutron activation. Practical applications of these methods are of great importance in this thesis as well as their usage in the counterterrorist fight.
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Concentration of selected metals in traditional and herbal teas
Brlíková, Eliška ; Křikala, Jakub (referee) ; Diviš, Pavel (advisor)
This thesis deals with determination of selected metals concentrations in loose green, black and herbal teas purchased in the Czech Republic and beyond. All samples were analyzed by ICP-OES. Most metals were not detected in the extracts. The final metal concentrations that have been detected in the tea extracts meet the legislative limits and do not bring a health risk to humans. The statistical processing of the measured results, based on different concentrations of selected elements, managed to distinguish the extracts from black and green teas.
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Determination of selected metals in fruit squashs
Drobilová, Marcela ; Vránová, Dana (referee) ; Diviš, Pavel (advisor)
The theoretical part of the thesis deals with the technology of fruit juices production and characteristics of the known varieties of elderberry. There are also summarized available information on the presence and properties of minerals in food. In the practical part of the thesis 17 different varieties of elderberry juice and commercially available juice sold as food supplements were analyzed using ICP-MS technique. The concentrations of 15 selected essential and toxic elements were determined in these juices.
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