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UV-photochemical generation of volatile species of tellurium and other transition metals
Jeníková, Eva ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee) ; Kanický, Viktor (referee)
This dissertation thesis is focused on UV-photochemical generation of volatile species of tellurium, ruthenium, rhenium and iridium coupled to methods of atomic spectrometry. In the first part, attention was paid to the optimization of parameters of UV-photochemical generation of volatile tellurium species and its application for speciation analysis of Te(IV) and Te(VI) in water samples. UV-photochemical generation was carried out in a UV-photoreactor, which consisted of a low-pressure mercury lamp wrapped with a polytetrafluoroethylene reaction coil that served as a reactor. Atomic absorption spectrometry with a continuum source of radiation and high resolution and atomization in a miniature diffusion flame were used to optimize the conditions of generation, which included the composition of the reaction medium, irradiation time and the addition of transition metals as modifiers. In order to achieve a higher sensitivity of determination, the generator was coupled to a triple quadrupole inductively coupled plasma mass spectrometer. Since efficient UV-photochemical generation of volatile species was achieved only from Te(IV), with no response from Te(VI), the feasibility of this technique for simple "non-chromatographic" speciation analysis was tested and a method for determination of Te(IV) and...
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Determination of selected metals in edible mushrooms in the Kladno district
ŠIMŮNKOVÁ, Eliška
The aim of this work was to determine the concentrations of rubidium, zinc, iron, copper, strontium and manganese in samples of edible mushrooms and to compare our results with other studies. The literary research contains brief information about mushrooms, soils, metals, used analytical method and research site. During the summer months of 2020 and 2021 twelve samples of seven edible mushroom species were collected from the forest between the former mines of Kladno for the purpose of the practical part. The whole practical part of the bachelor thesis was performed in the laboratory of the Department of Applied Chemistry, Faculty of Agriculture and Technology of the University of South Bohemia in České Budějovice. Measured values were recorded in tables and statistically processed. Through analysis we found out that a parasol mushroom belongs to mushroom species with the highest ability to accumulate metals. Among the analyzed samples we found the highest content of iron (1148 mg/kg), copper (150 mg/kg) and the second highest of manganese (339 mg/kg). On the other hand the least able to cumulate metals between analyzed mushroom species was red cracking bolete which contained the lowest contents of manganese (15 mg/kg) and strontium (1,6 mg/kg). The stink snake is worth mentioning because of its high strontium (10,1 mg/kg) and manganese (643 mg/kg) accumulation. Measured manganese content significantly exceeded the values measured in other analyzed samples.
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Determination of selected metals in edible mushrooms in the Příbram district
DVOŘÁKOVÁ, Hana
The aim of this work was to determine the concentrations of rubidium, cesium, lithium, strontium and supplemental elements of copper, iron, manganese and zinc in samples of edible mushrooms and to compare the measured concentrations with the studies mentioned in the literary research. In addition to the results of the studies, the literary research contains brief informations about mushrooms, individual elements, the used method and the monitored location. For the purposed of the practical part, 19 samples of nine edible mushrooms species were collected from the vicinity of a lead smelter in the village of Podlesí near Příbram. The samples were the first processed by microwave digestion and then analyzed by AAS (atomic absorption spectrometry). The whole practical part of the thesis was carried out in the laboratory of the Departemnt of Applied Chemistry, Faculty of Agriculture of the University of South Bohemia in České Budějovice. The analysis results were recorded in tables, statistically and graphically processed an evaluated in the discussion. From the analysis we found the species of mushoom with the most cumulate metals ability is a toadstool rosacea. Among the analyzed samples we found the highest concentration of strontium (22,5 mg/kg), lithium (0,6 mg/kg), iron (223,0 mg/kg) and manganese (69,7 mg/kg). On the other hand, the least cumulative species was boletus brown with the lowest concentrations of copper (10,1 mg/kg), iron (29,5 mg/kg) and manganese (5,2 mg/kg) being determined. The less cumulative species was also boletus edulis, which was found to have at least strontium (2,2 mg/kg) and lithium (0,3 mg/kg). It is worth mentioning the larch bolete, in which we have determined the greatest concentration of rubidium (364 mg/kg) and cesium (11,7 mg/kg), but the least of zinc (68,7 mg/kg). Likewise, a parasol mushroom absorps copper to a large extent (255 mg/kg), but on the contrary it contained the least cesium (0,5 mg/kg) and rubidium (11,8 mg/kg).
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The content of selected risk element in fruit bodies of mushrooms with medicinal benefits
VONDRUŠKA, Jan
This dissertation thesis is focused on determination of detrimental and essential elements in fruiting bodies of selected medicinal mushrooms. Auricularia auricula-judae, Tylopilus felleus, Pleurotus ostreatus, Flammulina velutipes, Armillaria ostoyae and Coprinus comatus were studied. Individual samples were collected from selected sites in South Bohemia. Pleurotus ostreatus was cultivated on the block of the substrate. Individual elements were determined using atomic absorption spectrometry with the flame or electrothermal atomization and flame photometry. Wild growing Auricularia auricula-judae was a good source of Ca and Mg (2200 a 2080 mg kg-1 dry matter) and Tylopilus felleus strongly accumulated Rb, Cd, Cu, Zn, Se and Mg (bioconcentration factors: 65.7; 2.47; 2.32; 1.93; 1.67 and 1.27). Another studied wild growing mushroom species was Flammulina velutipes; it was characterized with significant contents of Ca, Fe, Mg, Mn and Zn (375, 112, 1200, 26 and 98 mg kg-1 dry matter). For Armillaria ostoyae, high contents of the following elements were determined (mg kg-1 dry matter): Ag (5.6), Ca (149), Cu (29), Fe (186), Mg (1100), Mn (30) and Zn (40). The last wild growing species studied was Coprinus comatus. It strongly accumulated Ag, Cd, Cu, Se and Rb (bioconcentration factors: 12; 2.5; 2.3; 1.8 and 1.1). The concentrations of detrimental elements were generally rather low indicating no considerably negative effect on human health in the case of studied species consumed as a delicacy or used as food supplements. On the other hand, the mushroom species can be used as an alternative source of essential elements (especially Zn and Se). An experiment with enrichment of the cultivation substrate with zinc and selenium was performed in the case of Pleurotus ostreatus. The increase in the zinc content in fruiting bodies was low, thus it can be concluded that the level of enrichment indicates no considerable effect on the final content of zinc in fruiting bodies. The bioconcentration of selenium was totally different. The addition of 1 mg of Se (in the form of Na2SeO3) into the cultivation substrate (cca 2 kg) increased the content of Se in fruiting bodies to about 3 - 6 mg kg-1 dry matter. This content was one order higher compared to the Se content in fruiting bodies harvested from the substrate with no Se addition. In the case of the addition of 5 mg of Se, there was a further significant increase in the content of this element to about 40 - 60 mg kg-1 dry matter.
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The content of selected elements in fruiting bodies of mushrooms with ecological relationship to white birch
KREJSA, Jiří
The contents of 21 risk and essential elements were determined in fruiting bodies of four macrofungi species with ecological connection to white birch. Leccinum scabrum and Leccinum versipelle were common mycorrhizal edible mushrooms, while Piptoporus betulinus and Inonotus obliquus were parasitic mushrooms with medicinal effects. The samples were taken from two locations in Šumava mountains - near the town of Vimperk and near the small village of Křišťánovice. Simultaneously with fruiting bodies of mycorrhizal mushrooms, underlying substrates were taken for determination of bioconcentration factors.
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The fate of selected heavy metals in a constructed wetland
KREJSA, Jiří
This study is aimed at removal of cadmium and mercury from municipal wastewater using a constructed wetland with a horizontal subsurface flow. Samples of wastewater, sediments, aboveground and belowground biomass of common reed (Phragmites australis) were analyzed. Average concentrations of cadmium and mercury in inflow water were 0,10 ?g/l and 0,16 ?g/l and in outflow water 0,03 ?g/l and 0,06 ?g/l. Average efficiencies of cadmium and mercury removal were 64,2 % and 63,7 %, respectively. Concentrations of cadmium varied in range 0,008-0,016 mg/kg for aboveground biomass and 0,042-0,081 mg/kg for belowground biomass of common reed. Average concentrations of mercury were 0,010 mg/kg and 0,008 mg/kg for aboveground and belowground biomass, respectively. Average concentrations of cadmium and mercury in sediments were 0,15 mg/kg and 0,15 mg/kg at the distance of 1 m from inflow zone and 0,03 mg/kg and 0,10 mg/kg at the distance of 10 m from inflow zone. Results showed that both cadmium and mercury were predominantly removed from wastewater at the beginning of the wetland bed.
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Atomization of hydride forming elements in dielectric barrier plasma discharges
Baranová, Barbora ; Kratzer, Jan (advisor) ; Hrdlička, Aleš (referee)
The aim of this diploma thesis was to optimize the atomization conditions of two hydride forming elements - bismuth and tellurium in dielectric barrier discharge (DBD) plasma atomizers using atomic absorption spectrometry (AAS) as a detector. Two types of electrode constructions of planar DBD atomizers were studied: glued and sputtered electrodes while two construction of high voltage power supply sources were investigated employing either a sinusoidal or square wave modulation of high voltage function. The effect of the gas phase dryer included in the apparatus upstream the atomizer was also investigated. A nafion membrane tube dryer was identified as the most effective one. Its efficiency was verified using optical emission spectrometry. With the nafion tube included in the apparatus, two main parameters of DBD atomizers were optimized: the voltage of the power supply source and argon flow rate, which served as a discharge gas. Using optimal conditions, analytical characteristics were determined for all atomizers used and these were subsequently compared with those achieved in an externally heated quartz (multi)atomizer (MM)QTA. In the case of bismuth, the optimal argon flow rate was determined to be 75 cm3 min-1 for all atomizers. The optimal value for the power supply source with sinusoidal...
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Determination of calcium and magnesium in honey samples by atomic absorption spectrometry
Čudová, Andrea ; Hraníček, Jakub (advisor) ; Šíma, Jan (referee)
This bachelor thesis is focus on the determination of calcium and magnesium in selected honey samples. Determination is performed by atomic absorption spectrometry with a flame atomization technique (F-AAS) by using an acetylene-air flame. The first part of the bachelor thesis is devoted to finding the optimal conditions of the method for further measurement of individual honey samples. These parameters are beam height above the burner edge and acetylene flow rate. Then, under these optimal conditions, the basic characteristics of calcium and magnesium determination (repeatability, sensitivity, limit of detection and limit of quatification) were found. In the second part of this bachelor thesis, the calcium and magnesium determination are performed in the honey samples. A total of 15 honey samples are analysed. The honey samples are prepared by local beekeepers from Czech Republic and retail chains (Tesco). The measured values are recorded in tables and statistically evaluated. The determined calcium concentrations range is 7.11 - 66.8 µg/g, for magnesium to 8.79 - 92.2 µg/g. Finally, the values obtained for honeys from the Czech Republic are compared with data reported in foreign studies. Key words: Atomic absorption spectrometry, flame atomization, magnesium, calcium, honey
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