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Development of the simultaneous analysis methods on the HR-CS-ET-AAS device and their use in environmental analysis
Jurnečka, Roman ; Doležalová Weissmannová, Helena (referee) ; Komendová, Renata (advisor)
This thesis deals with the development of simultaneous determination methods using atomic absorption spectrometry with a continuous radiation source and high-resolution monochromator. The determination methods were developed especially with regard to the analysis of environmental matrices. Two methods of simultaneous determination were developed with the application of three types of environmental samples. The first of them was focused on the simultaneous determination of nickel and iron in tea leaves. This method was also applied to soil samples. The second method is the determination of manganese and iron in water. Here I also examined the influence of the modifier. Furthermore, the combination of wavelengths of the already established method of simultaneous determination of cadmium and iron in oat products was taken from the literature. As part of the thesis, this method was optimized to determine these specific elements in tea. The primary advantages of simultaneous analysis include the saving of chemicals, including argon, as well as less time-consuming operation. The developed methods can be put into practice. The output is a design of a laboratory task for the introduction of simultaneous analysis into teaching.
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Research on the content of risk elements in the material of PET bottles
Kryštofová, Petra ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This thesis deals with the research of the content of risk elements in the material of rPET (recycled polyethylene terephthalate), supplied from various countries, and the study of different factors (type of liquid, temperature) on the migration of antimony from this material. The recycling process has the potential to increase the content of unwanted substances and promote the formation of degradation products of chemical additives and by-products of polymerization, thus contributing to higher migration of these substances into food or food simulants [1]. The supplied rPET samples were subjected to total decomposition in an environment of concentrated sulfuric and nitric acid under the influence of microwave radiation prior to analysis. Prepared samples were analyzed by atomic absorption spectroscopy (AAS) techniques. The contents of Sb and Zn were determined by flame atomic absorption spectrometry (FAAS), and the concentrations of Pb, Cu, Zn, Cd, Cr, and Ni were determined by electrothermal atomic absorption spectrometry (ETAAS). Additionally, the concentrations of Sb were determined by this method in migration experiments. This thesis builds upon the author's bachelor's thesis, which included pilot experiments.
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Determination of selected heavy metals in samples of great tits feathers by inductively coupled plasma mass spectrometry
Adamová, Simona ; Hraníček, Jakub (advisor) ; Kozlík, Petr (referee)
EN As a result of human activity, a number of polluting substances are released into the environment. Heavy metals are one of the types of these contaminants. Their accumulation in the environment can have a negative impact on living organisms, including humans. For this reason, environment quality monitoring has become an important activity. Great tit (Parus major) can be a suitable bioindicator of the level of environmental contamination by heavy metals, which is acceptable mainly due to its abundance and occurrence in the vicinity of human settlements. This diploma thesis deals with the determination of six selected heavy metals in feather samples of these songbirds from several parts of the Czech Republic and other European countries. High pressure microwave mineralization in the presence of acids was used to prepare the samples. Selected heavy metals were determined using inductively coupled plasma mass spectrometry (ICP-MS) technique, which is also suitable for ultratrace analysis due its very low limits of detection.
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Nickel alloys in aerospace
Šprincl, Jan ; Nopová, Klára (referee) ; Němec, Karel (advisor)
The aerospace industry is one of the fastest growing industries today. Increasing demands on the efficiency and fuel consumption of jet engines can be met, among other things, by using higher quality materials, which clearly include nickel-based superalloys, which can meet these demands. This work provides an overview of these materials: both the building block of the whole structure - nickel, superalloys in general, and especially those nickel-based. It deals with the composition of the microstructure formed by the austenitic matrix ( phases) most often cured by carbide or substitution precipitates, unique mechanical properties, but also the influence of high temperatures and creep on the degradation of these properties. The work also includes a comparison of selected superalloys from different perspectives, especially according to the type of particles that cure the matrix or the effect of loading on the superalloy in the presence of thermal oxidation environment. Depending on the area of application, these materials are predestined for further future development and improvement, because their unique properties in areas with extreme conditions are irreplaceable for the time being.
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Study of the content of risk elements in soils and plant material
Vlčková, Renáta ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the study of the content of selected heavy metals (Zn, Ni, Fe, Mn) in soils and mushrooms. The flame atomic absorption spectrometry method was used to determine the heavy metal content. Fungi and soil samples were collected at 18 sites in the Jeseníky region. The concentrations of heavy metals in the mushrooms were in the range from 140–582 mg/kg Zn, 48–380 mg/kg Fe, 5–19 mg/kg Mn and 3–8 mg/kg Ni. Zinc had the highest concentration value in all mushroom species. In soils, the concentrations of heavy metals ranged from 10–72 g/kg Fe, 52–1,000 mg/kg Mn, 29–115 mg/kg Zn and 6–50 mg/kg Ni. Iron was the most abundant element in the soils. Mushrooms contamination was assessed as a health risk in the study area. However, the pollution of forest soils was assessed as satisfactory and thus the productive function of the soil is not impaired. The type of forest cover was found to have minimal effect on the chemical composition of the soils.
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Distribution, binding and mobility of Ni in soil in the closed Ni mining area in the vicinity of Křemže
Pipková, Zuzana ; Ettler, Vojtěch (advisor) ; Vaněk, Aleš (referee)
Soils in the vicinity of Křemže in the Southern Bohemia are developed on altered ultrabasic rocks. The occurrence of Ni-hydrosilicate and Fe-rich ores in this area lead to their mining mainly during 19th century, then during the World War II. This thesis is focused on distribution and availability of Ni, Cr and Co and accompanying elements in soils at former mine and prospection sites (2 soil profiles and 32 topsoil samples at historical surface mine area). In all soil samples, physico-chemical parameters (pH, TOC, TS) and bulk concentrations of Al, Ca, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb and Zn were measured. In addition, deionised water, DTPA and EDTA extracts were used to determine the (bio)availability and mobility of these elements. Some of trace elements were found in elevated concentrations in the mining area topsoils; mean Ni: 1175 mg/kg (range 545-2849 mg/kg), mean Cr: 416 mg/kg (240-849 mg/kg), mean Co: 127 mg/kg (65-238 mg/kg), mean Fe: 49155 mg/kg (30460-113800 mg/kg), mean Mg: 12648 mg/kg (8795-18770 mg/kg) and mean Mn: 1480 mg/kg (1028-2319 mg/kg). In soil profiles the Ni availability decreased with depth. In the uppermost organic O horizon in forest soil profile, 19.5 % and 23.8 % of total Ni was extracted by DTPA and EDTA, respectively. The extractabilities are decreasing down to mineral...
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Determination of zinc, cadmium and nickel in leaves by inductively coupled plasma-mass spectrometry
Plodík, Michal ; Hraníček, Jakub (advisor) ; Červený, Václav (referee)
Práce je zaměřena na stanovení těžkých kovů (zinku, kadmia a niklu) v listech různých druhů stromů. Vzorky byly odebrány z různých lokalit na území České republiky. Pro analýzu byla použita hmotnostní spektrometrie s indukčně vázaným plazmatem, která je dostatečně citlivá pro předpokládané nízké koncentrace vybraných kovů. Pro stanovení koncentrace byla klíčová příprava vzorků pro mikrovlnný rozklad v koncentrované kyselině dusičné. Naměřené koncentrace sledovaných kovů se lišily nejen mezi lokalitami a jednotlivými rostlinnými druhy, ale také v rámci jedné lokality. Použitá metoda ICP-MS prokázala dostatečnou citlivost i u prvků s přirozeně nízkou koncentrací v životním prostředí, což bylo v této práci kadmium.
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Computational simulation of the compression test of the open cell metal foam
Homola, Václav ; Skalka, Petr (referee) ; Ševeček, Oldřich (advisor)
The thesis presents computational simulation of compression test of a nickel foam and the 3D reconstruction of micro-CT images was utilized to generate the foam’s model of geometry. Explicit FEM is used to simulate compression test using software tool LS-DYNA and the stress–deformation curve is obtained together with deformed model’s mesh used for subsequent analysis. Sensitivity analyses were performed to configure the model and ensure best fit with values obtained during real-life experiment. The ANSYS Classic environment was then used to simulate tensile test of the foam compressed to various thicknesses. The tensile moduli in three mutually perpendicular directions of nickel foam were computed and the results were compared to experimental values as well. The results of tensile test simulation revealed considerable anisotropy of the foam’s elastic behavior. It can be said that the measured experimental data correspond very well with the elastic properties obtained from simulation up to certain level of compression. Analysis of the relationship between the element size and tensile moduli showed a significant difference between fine and coarse mesh. The optimal level of discretization and the overall model configuration ensuring high level of accuracy is proposed in this thesis.
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