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Development of Diffusive Gradients in Thin Films Technique for Determination of Mercury in Aquatic Systems
Szkandera, Roman ; Chýlková, Jaromíra (referee) ; Čelechovská, Olga (referee) ; Řehůřková, Irena (referee) ; Dočekalová, Hana (advisor)
The theoretical part of this doctoral thesis deals with determination of mercury and its species in aquatic systems. Special attention is paid to the use in situ sampling technique diffusive gradients in thin films technique (DGT) and its development. Current resin gels used for determination of mercury by DGT technique Duolite GT-73, Chelex-100 and Spheron-Thiol are described. Moreover, new types of resin gels including Iontosorb AV modified by imidazole or 6-mercaptopurine and commercially available titanium dioxide. Preparations of resin gels and their basic tests in model solution according to DGT Research are described. Mercury accumulation in relation to time and basic recovery test were tested and capacity of resins was determined. All tested resins meet the requirements of basic DGT Research tests and relative standard deviations of mercury in recovery tests were lower than 10 %. The sorption capacity of resins varied from 1,5 to 6 µmol.l-1 and decreased in following order: Duolite GT-73 > ISAV-IM > Chelex-100 > Spheron-Thiol > TiO2 > ISAV-MP. Mercury sorption on resins was investigated under conditions similar to those in natural waters. It was found that the ionic strength commonly occurring in natural waters does not affect the determination of mercury. The presence of chlorides significantly affects the determination of mercury using DGT with titanium dioxide and therefore this sorbent can not be recommended for the determination of mercury in sea waters. The accumulated amount of mercury, depending on the pH shows that all the sorbents can be used in natural waters with pH in the range form 4 to 8. Mercury sorption is most affected by the presence of humic acids, especially at ion-exchange resins containing other than thiol functional groups. The exception is titanium dioxide for which physical sorption of humic acid metal complexes is typical. Cadmium and copper in model solutions in the molar balance of the excess mostly influenced the sorption of mercury on Chelex-100 and Spheron-Thiol resins. After laboratory tests, the DGT units with studied sorbents were used for the determination of mercury in natural waters of South Moravia (Svratka, Jihlava and Svitava river). Mercury concentration determined using DGT units containing Duolite GT-73 resin was comparable to the total dissolved concentration of mercury in river water provided by direct determination using AAS technique. Order of magnitude smaller concentrations than the total dissolved mercury concentration were found using DGT containing Spheron-Thiol and ISAV-MP resins. These sorbents are probably able to capture only mercury present in the form of labile complexes. This can be used for speciation analysis if more DGT units with different resins are deployed together. Subtracting the measured DGT Spheron-Thiol or ISAV-MP concentrations from the DGT Duolite GT-73 concentration, information about the amount of mercury present in the form of stabile complexes can be obtained. The amount of mercury determined after application of DGT units containing ISAV-IM, Chelex 100 or TiO2 can probably represent the mercury fraction bound in even weaker complexes than fraction determined by Spheron-Thiol and ISAV-MP DGT.
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Metals Transport in the System Soil/Plant. Comparison of the Active and Passive Sampling Method (The Diffusive Gradients in Thin Films Technique)
Trávníčková, Jana ; Janoš, Pavel (referee) ; Chýlková, Jaromíra (referee) ; Čelechovská, Olga (referee) ; Dočekalová, Hana (advisor)
The doctoral thesis deals with comparison between copper uptake by radish (Raphanus sativus L.) and concentration of copper measured by a DGT-device and concentration of copper obtained by extraction with generally used extraction agents (HNO3, NaNO3 and water). Plants were cultivated in pot experiments on a tested non-treated and gradually spiked soil. The amount of copper was determined in various part of radish (whole plant, above- and below-ground part) after mineralization in the APION mineralizer by ET – AAS. The highest concentration was in belowground part, especially in root tissues and sheel of root bulb. It confirms copper is associated with cell walls. The amount of copper taken by radish up does not pass beyond sanitary standards not even in spiked soils and consummation of radish is not unhealthy. Good correlations were found between copper concentration in radish and the amount of copper extracted with HNO3, NaNO3 and water and the amount found in soil solution. Results of extraction with HNO3 confirmed the amount of copper was stable in spiked soils during the pot experiments. The DGT experiments have shown that the rate of resupply from the solid phase to soil solution is constant during the deployment time. Whereas the release of copper decreases after 24 hours in natural soil. Copper added to soil in form of cupric ions is present in the different form after one month-equilibration than copper present in unspiked soils. The results obtained by DGT measurements were approximately up to two orders of magnitude lower than copper concentration obtained by leaching with sodium nitrate. The extraction with sodium nitrate does not provide true reflection of metal availability to plant root system and soil microorganism. High values of correlation coefficients (R2 > 0,9) were found between concentration of copper in radish plant and the concentration of copper in soil solution measured by DGT technique. Concentration of copper in soil solution was three times higher than concentration measured by DGT technique. Soil solution contains species of copper that are not measured by DGT technique and available to plants. Concentration of metals obtained by DGT measurements is more closely to real concentration of bioavailable forms of metal in soil. Therefore it is possible to recommend the DGT technique as a technique for determination of bioavailable forms of copper in soils.
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Application of Separation Techniques Connected with Mass Spectrometry for the Analysis of Environmentally Important Compounds
Mácová, Daniela ; Čelechovská, Olga (referee) ; Márová, Ivana (referee) ; Demnerová, Kateřina (referee) ; Čáslavský, Josef (advisor)
The identification of the hydrolysis and photodegradation products of flexible polyurethane foams (PUFs) with addition of biooriginated and biodegradable additive was the first topic of this dissertation work. Separation of polyurethane foam hydrolysis degradation products, designed for ecotoxicological tests, was managed by high-performance liquid chromatography coupled with mass spectrometry (HPLC/MS). The degradations product structure was elucidated by tandem mass spectrometry (MSn). PUF photodegradation products were obtained by exposure of materials by irradiation at 254 nm. Semi-volatile degradation products were isolated from the exposed polyurethane by n-hexane extraction; volatile compounds were collected by solid phase microextraction (SPME). Gas chromatography with mass spectrometry (GC/MS) and complete orthogonal tandem gas chromatography with mass spectrometry (GCxGC/TOF MS) was used for separation and identification of photodegradation products. The influence of the bio-filler on the character of degradation products and the possible effect of PUF degradation products on the environment was discussed at the end of this section. The determination of isoprostanes – markers of oxidative stress in tissues of beadlet anemone (Actinia equina) was the subject of the second topic. F2-isoprostanes were synthesized from the arachidonic acid. With thereby prepared isoprostanes the method of determination by liquid chromatography with tandem mass spectrometry (HPLC/MS/MS) was developed and optimized. The isoprostane isolation process from the Actinia equina tissues was optimized with solid phase extraction (SPE). The resulting methodology was used to quantify isoprostanes in tissues of anemones, which were exposed to both moderate and high temperature changes. The temperature changes were used to initiate the oxidative stress in organisms. In addition, concentration levels of unknown compounds were also monitored. These unknown compounds were extracted from tissues together with F2-isoprostanes and their identity is discussed in this dissertation work too. The possibility of using isoprostane levels in the Anthozoa tissues for the oxidative stress monitoring is discussed in the conclusion of this work.
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Determination of palladium by ET-AAS after previous preconcentration by solid phase extraction
Hajdová, Jana ; Čelechovská, Olga (referee) ; Komendová, Renata (advisor)
The theoretical part of this master’s thesis focuses on the characteristic of Palladium, his uses in the automotive convertors, the occurrence in the environment, bioaccumulation and human health risks. Next there are described the basics of biomonitoring and summarize suitable biomonitoring method for capturing airborne dust. There are also evaluated appropriate methods for preconcentration and determination of Palladium. The aim of experimental part of this thesis is description and evaluation optimalization preconcentration method SPE by using sorbents silicagel C18 and QuadraSil TA. Optimization of method conditions of electrothermal atomic absorption spectrometry (ET – AAS). The determination of Palladium using optimal conditions follows in real samples in the form of exposure lichen (Hypogymnia physodes) by automobile traffic in Brno.
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Toxic metals in water and sediments of Brno water reservoir
Bořek, Tomáš ; Čelechovská, Olga (referee) ; Dočekalová, Hana (advisor)
Diploma thesis deals with usage of the diffusive gradients in thin films technique (DGT) for the determination of labile metal species in the surface water and sediments of Brno water reservoir. Sediment and water samples were collected on the selected sides of Brno water reservoir on September and October 2008. The DGT technique was used for determination of depth profiles of Fe, Mn, Pb, Cd, Zn, Cu, Ni and Al. The DGT probes with three different thicknesses of diffusive layer were applied into the sediment samples. The obtained results gave the information about release of metals from solid phase into the pore water of sediment. The concentrations of Fe, Mn, Pb and Cd in sediments were determined by atomic absorption spectrometry after microwave decomposition. The DGT technique was used also for determination of Fe, Mn, Pb and Cd in surface water from Brno water reservoir.
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Investigation of Miniature Devices for Collection of Hydride Forming Elements in Atomic Spectrometry Methods
Krejčí, Pavel ; Čelechovská, Olga (referee) ; Janoš, Pavel (referee) ; Otruba, Vítězslav (referee) ; Dočekal, Bohumil (advisor)
Capability of a prototype of miniature collection device based on a strip of the molybdenum foil for collecting hydride forming elements (As, Se, Sb and Bi) was studied. The device was combined with a miniature hydrogen diffusion flame for detection by atomic absorption spectrometry. The conditions for trapping and subsequent vaporization of analytes of interest were optimized. A twin-channel hydride generation system was used for study of mutual interference effects of co-generated hydride forming elements. The influence of modification of the molybdenum surface with noble metals - Rh, Pt and Ir on trapping and vaporization processes was also studied and changes of microstructure of the foil surface after modification were investigated using scanning electron microscope equipped with energy dispersive x-ray analyzer and electron backscattered diffraction system. Complementary radiotracer and radiography experiments were performed in order to determine trapping efficiency and to assess the spatial distribution of collected analytes within the device. Practical application of the method was demonstrated on determination of antimony in water samples at trace level. Possibility of multi-element analysis was demonstrated by combining the collection device with atomization and excitation of the analyte in microwave induced plasma and with detection by atomic emission spectrometry method. The results of the experiments proved that tested miniature collection device is capable of trapping analytes that form volatile hydrides. This device can be coupled to various types of atomizers, typically used in spectrometry methods. Thus, very sensitive and specific detection of hydride forming elements can be performed.
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Study of Generation, Trapping and Atomization of Hydride Forming Elements for Atomic Spectrometry
Furdíková, Zuzana ; Sommer, Lumír (referee) ; Čelechovská, Olga (referee) ; Řehůřková, Irena (referee) ; Dočekalová, Hana (advisor)
Interference effects of co-generated hydrides of arsenic, antimony, bismuth and selenium on trapping behavior of selenium or antimony hydrides (analytes) within iridium modified, transversely heated graphite tube atomizer (THGA) was investigated. A twin-channel hydride generation system was used for independent separate generation and introduction of analyte and interferent hydrides, i.e. in simultaneous and/or sequential analyte-interferent and interferent-analyte mode of operation. Influence of the analyte and modifier mass, interferent amount, trapping temperature and composition of the gaseous phase was studied. A simple approach for elimination of mutual interference effects by modification of the gaseous phase with oxygen in substoichiometric ratio to chemically generated hydrogen is proposed and suppression of these interference effects is demonstrated. A hypothesis on mechanism of trapping and mutual interference effects is drawn.
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Mercury in waste water
Paříková, Lucie ; Čelechovská, Olga (referee) ; Dočekalová, Hana (advisor)
In the time period from November to April of the academic year 2007/2008 presence of mercury and its forms was monitored in the waste waters of Faculty of Chemistry, VUT in Brno. The level of mercury was determined as total mercury with help of the atomic absorption spectrometry method and in available forms by diffusive gradient in thin film technique.
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Preconcentration of Trace Analytes on Modified Sorbents and their Determination on Waters
Holubová, Zuzana ; Čelechovská, Olga (referee) ; Holoubek,, Ivan (referee) ; Otruba,, Vítězslav (referee) ; Sommer, Lumír (advisor)
The work has been focused on the preconcentration techniques for determination of 9Be, 51V, 59Co, 60Ni, 89Y, 111Cd, 208Pb, 232Th and 238U on the modified sorbents, all measurements were performed on ICP-MS. The instrument setup was optimized. The solution of internal standard (200 µg•l-1) was used during all measurements. The internal standard were chosen as follows: 6Li for 9Be, 45Sc (51V), 72Ge (59Co, 60Ni, 89Y), 103Rh (111Cd), 209Bi (206Pb, 207Pb, 208Pb, 232Th and 238U). Another parameters such as influence of mineral acids (HCl, HNO3), surfactant (Septonex®, Zephyramin, Ajatin, Brij 35 and Sodium dodecyl sulphate) and organic reagents (Ammonium pyrrolidinedithiocarbamate, 8-Hydroxyquinoline-5-sulphonic acid, 1,2-Dihydroxyanthraquinone-3-sulphonic acid and 4-(2-Pyridylazo)resorcinol) and the effect of some matrix components on intensity of instrument signal determination was investigated. For preconcentration polar Silicagel and modified nonpolar Silicagels (Silicagel-C18, C8 nad Phenyl) were used. Another experimantal part was dedicated to preconcentration on nonpolar Amberlite XAD-16 and Strata SDB-L and intermediately polar sorbent Amberlite XAD-7. Recoveries of sorption process were observed in the presence of all testing types of surfactants in certified concentration 5•10-4 mol•l-1. Surfactants were always applied in the conditioning step. The suitable combinations of surfactant and organic reagent were tested for increasing of recoveries of analytes. Testing organic reagents were added in five times mass excess againts concentration of analytes, the concentration of the organic reagents was 900 µg•l-1. The organic reagent was always added to the solution for preconcentration before this solution was led on the sorbent. The composition and a necessary volume of elution mixture for quantitative elution were tested, too. Only one sorbent was chosen from each group of sorbents with similar properties. The chosen sorbent showed the best recoveries in majority of target analytes. The highest recoveries from silica-group was reached for Silicagel-C18, from nonpolar Amberlite was chosen Strata SDB-L and intermediately polar Amberlite XAD-7. The influence of some matrix components (anionts and cations) on recoveries of analytes was investigated for chosen sorbent. The optimized process was applied on real samples of nature water and industry water. In experimental part all analytes are marked as specific izotopes, which were measured by ICP-MS. Of course, all izotopes of analytes undergo preconcentration techniques.
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