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Cycling of mercury and mercury species in the environment
Finsterlová, Hana ; Diviš, Pavel (referee) ; Dočekalová, Hana (advisor)
This bachelor’s thesis deals with the role of mercury in an environment. It summarizes informations about properties of mercury and its species. The thesis is engaged in the presence of mercury in atmosphere, water, soil and sediments. It deals with individual mercury intakes into the environment, anthropogenic or natural, and it follows transport of mercury between individual components of environment. Part of this thesis is given to the accumulation of mercury and mercury species into plants and organisms. It points out the toxicity of mercury, mercury species, and their effect to human organism. In the last chapter there is a resume and description of the instrumantal methods, which are commonly used for determination mercury and its compounds.
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The antioxidant activity of selected species of small fruit
Křenová, Alena ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
This diploma´s thesis deals with the determination of total antioxidant activity of red and white gooseberries and red, white and black currants. There are available information about small fruits, an overview of natural and synthetic antioxidants and a summary of the methods to determine the total antioxidant activity in the theoretical part. Frozen fruit samples were provided by Research and Breeding Institute of Pomology Holovousy Ltd. in the project QI111A141 – Research of new technologies in the cultivation of gooseberries and currants with a focus on quality and use of fetuses (Ministry of Agriculture). The total antioxidant activity of red and white gooseberries and currants was measured by spectrophotometric methods using free radicals ABTS•+ and DPPH and was expressed as a Trolox equivalent. The total antioxidant activity of black currants was measured by electron paramagnetic resonance using free radicals ABTS•+ and DPPH and expressed as a TEACABTS and a TEACDPPH. There were measured 8 species of red gooseberries, 6 species of white gooseberries, 12 species of red currants, 6 species of white currants and 8 species of black currants in this thesis. The highest values of total antioxidant activity showed species of red and white gooseberries Alan, Karmen, Pax and Invicta and species of red and white currants Rovada, Orion and Olin. Among black currants, species Ometa and Ruben had the highest values of total antioxidant activity.
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Determination of selected chemical parameters of fruit of new currant varieties
Pelikánová, Blanka ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
Presented diploma thesis is dedicated to the determination of selected chemical parameters of fruits of new currant varieties. The theoretical part is focused on the characteristics of currant, the biologically active substances of its fruits and also the utilization of current in the food industry. Further part of the theory deals with the main chemical parameters which were examined: polyphenols, anthocyanins, ascorbic acid and antioxidant activity. In the practical part there were determined selected chemical parameters in six white, twelve red and thirteen black varieties of currant. Anthocyanins and polyphenols have been determined spectrophotometrically. The content of ascorbic acid in selected varieties of currant was determined by HPLC. As a technique for the determinationof the antioxidant activity was selected the method of free radical DPPH.
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Study of the effect of fertilizer containing wheat bran on lettuce growth
Smrčková, Kamila ; Pořízka, Jaromír (referee) ; Diviš, Pavel (advisor)
The aim of the work was to perform growth experiments on a laboratory scale with soil, which was enriched with 2,5 vol. % of wheat bran/coffee grounds/biochar and to study soil and growth characteristics on Lactuca sativa L. The coffee grounds were added raw or modified by oxidation/extraction. Phytotoxic properties of coffee grounds were confirmed by germination tests, although there was an effort to reduce the content of phenolic substances by oxidation /extraction. Soil additives caused an increase in content of organic matter, water capacity, pH and conductivity of all mixtures compared to the control soil. Elemental analysis of soils before cultivation did not show any positive effect on the content of mineral elements compared to the control soil. On the other hand, higher mineral (P, Mg, Ca, K, Mn, Fe, Cu and Al) content compared to soil was recorded cultivation experiments. Chlorophyll a was the most abundant in cultivated plants and reached the lowest concentration in plants grown in a mixture with EXKS. Salads differed in mineral content, too. Salads with the highest content of phosphorus were growed on the mixture BU+OT+PŮDA. On the contrary, content of potassium is salads was negatively affected by mixture with EXKS. Microelements (Fe, Zn, Al, Cu, Cr and Mn) were most affected in the salad by the addition of raw coffee grounds and OXKS2.
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Content of selected alkaloids in tea and coffee
Trenzová, Kristina ; Divišová,, Radka (referee) ; Diviš, Pavel (advisor)
This master thesis deals with content of selected alkaloids in tea and coffee samples. Theoretical part of this paper focuses on basic characteristic of Camellia sinensis and Coffea arabica/canephora, its processing technology and chemical composition. Furthermore, there is discussion about effects of methylxanthines on the human body, the effects on health and metabolism in plants capable of accumulating methylxanthines. The samples were extracted into an organic solvent and also prepared in the aqueous phase according to the recommended preparation. This thesis focuses on xanthine alkaloids - caffeine, theobromine and theophylline. Of the coffees, Robusta coffee from India had the highest caffeine concentration (1730 mg/l), which corresponds to 1,72 % in coffee. From Arabica samples, the highest caffeine concentration was measured for Honduras coffee (1115 mg/l), which is 1,11 %. The highest values of tea samples were measured for Ceylon types, the highest caffeine concentration was measured for black Ceylon 2087 mg/l, which is 2,08 %. The highest concentration of theobromine was in Ceylon gunpowder (175,4 mg/l). Alkaloids passed into aqueous solutions with almost 100 % efficiency, depending on temperature and time. The best penetration was for coffees prepared by a mocha teapot and for pu-erh teas. The worst for green teas and maté samples.
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Evaluation of the influence of the pasterization and filtration on selected chemical components of beer
Vopelková, Dominika ; Diviš, Pavel (referee) ; Pořízka, Jaromír (advisor)
The aim of this work was to study the influence of the pasteurization and filtration on selected chemical compounds in beer. Specifically, the influence on elemental composition, content of organic acids, carbohydrates and phenolic substances was studied. Optical emission spectrometry with inductively coupled plasma (ICP-OES) was used for elemental analysis of beer. Analysis of organic acids was evaluated by Ion chromatography. For analysis of carbohydrates was used High performance liquid chromatography with ELSD detector (HPLC-ELSD), phenolic compounds was evaluated by HPLC with diode array detector (HPLC-DAD). Data from analysis of beer was performed by usage of statistical methods (analysis of variance and principal component analysis). Parameters that showed the most significant differences between individual groups of beers were obtained. Correlations between the variables and the technological beer processing operations were found. 12 parameters of total 23 were affected. The effect of filtration and pasteurization was observed in content of the iron, silicon, potassium and magnesium, malate, monosaccharides glucose and fructose and phenolic compounds.
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Determination of selected parameters in the Czech lager beer
Žáková, Kateřina ; Gregor,, Tomáš (referee) ; Diviš, Pavel (advisor)
The topic of this bachelor thesis is to establish an concentration of selected substances at czech beers lager type. In the first part of the work there are in a range of the theory described basic materials for a beer production and its production proces too. A large part is dedicated to describing of analytical methods used for an analysis of choosen phenolic substances, organic acids and inorganic substances (elements). In the experimental part the measured results are discussed. The target of this work was to compare a composition and to find specific or characteristic ingredients in selected brands type lager produced in Czech republic. Further there were compared the samples with the Czech Beer designation and the samples without those signing.
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Analysis of selected elements in milk by ICP-OES
Sekaninová, Renáta ; Vespalcová, Milena (referee) ; Diviš, Pavel (advisor)
This Master's thesis is dealing with elementary analysis of milk. Theoretical part describes general characteristics, terminology with basic legislature and classification of milk. Large part is focused on chemical composition, especially on description of mineral substances selected for analysis in experimental part of this thesis. Choices of elementary analysis and preparation of samples for ICP-OES method conducted by other authors are also mentioned. Specification of emission spectrometry with inductively coupled plasma is crucial, a technique used for purposes of this dissertation. Experimental part deals with preparation of samples, approach of analysis and processing of measured results. The aim of this part is to compare concentration of analyzed elements in different kinds of milk. Samples from 15 different kinds of milk were used for analysis, which were determined by ICP-OES method. Results were compared to each other in discussion as well as with results from other authors.
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Basic chemical characteristics of juices of selected white gooseberry varieties
Zelníčková, Jaroslava ; Diviš, Pavel (referee) ; Vespalcová, Milena (advisor)
Theoretical part of this bachelor thesis includes taxonomical classification of gooseberry, deals with biological characteristics, active substances contained in fruits of gooseberry and its using as well with description of the methods by research detection. In the experimental part primary nutritional parameters of chosen gooseberry species were analysed including orientation juice yield, soluble solids, pH, dry matter, titratable acids, formol number and reducing sugars. There were analysed following species of gooseberry: Reflamba, Mucurines, Rixanta, Veliš, Citronový obří, Darek, Prima, Invicta, Zlatý fík a Zebín. Individual species and cultivars were compared based on the results.
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Characterization of the resin gels for mercury determination by DGT technique.
Finsterlová, Hana ; Řezáčová, Veronika (referee) ; Diviš, Pavel (advisor)
The aim of this thesis is testing of resin gels used in diffusive gradients in thin films technique (DGT) for determination of mercury in natural waters. The sorbets, chosen for preparation of resing gels were: Duolit GT- 73, Spheron- Thiol, and Chelex 100 and newly modified sorbent Iontosorb AV. At the beginning of work, the preparation procedure of all resing gels was optimized. After optimalization of preparation procedure the resin gels were tested in mercury model solutions. The recovery test and time dependence test were performed. When the basic tests were finished, they were followed by the tests of influence of natural ligand (humic acids and chlorides), and other parameters (above all pH and ionic strenght), on mercury determination by DGT technique.
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