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Printed transparent oxide conductors
Bartoš, Radim ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
Thin films of tin oxide doped by fluorine or antimony were prepared by spincoating technique and material printing technique. Plenty of inorganic and organic coumpouds were used as precursors of fluorine and antimony. Sheet resistence of films were measured by 4-probe method and film thickness were determined by contact profilometer. Films were analyzed by Xray diffraction (XRD) and scan electron microscopy (SEM).
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Antimony determination by electrochemical hydride generation
Suchá, Lenka ; Hraníček, Jakub (advisor) ; Rychlovský, Petr (referee)
The aim of the presented bachelor thesis is to study the possibilities of the electrochemical hydride generation of volatile antimony hydride, using two newly constructed electrolytic cells. In this work, the properties of the cells were studied and consequently the basic characteristics of antimony determination obtained using new cells were compared with the chemical hydride generation method. At the beginning of the work, the relevant working parameters of both electrolytic cells were optimized. Under the optimal working conditions the calibration and other characteristics were carried out for antimony determination. Using the electrochemical hydride generation with thin-layer electrolytic cell and tubular cell and chemical hydride generation the sensitivity 3.40·10-3 l·μg-1 , 6.10·10-3 l·μg-1 and 2.10·10-3 l·μg-1 respectively were obtained. Finally, the influence of oxygen introduction in the different part of experimental setup was studied. This oxygen addition caused the characteristic and well-reproducible absorption peak. Key words Atomic absorption spectrometry, electrochemical generation of volatile compounds, quartz tube atomizer, thin-layer and tubular electrolytic cell, antimony
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Construction of miniature flow-through cells for electrochemical generation of volatile compounds
Hraníček, Jakub ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
(EN) The presented dissertation thesis summarizes the new results of electrochemical generation of volatile compounds usable in atomic spectral methods. The main aim of this work is to develop and to characterize new types of electrolytic flow-through cells and to examine their possibilities of determination of arsenic, selenium and antimony by using the electrochemical hydride generation technique coupled with atomic absorption spectrometry with a quartz tube atomizer. Individual electrolytic cells were designed and constructed to comply with two important requirements. The cathode chamber of the electrolytic cell should have a minimal volume and a high efficiency of analyte conversion to the volatile hydride. Constructed electrolytic cells are divided into the construction groups and described in the experimental part. Selenium was chosen as the first analyte. The relevant working parameters (such as type, concentration and flow rate of electrolytes, generation current and carrier gas flow rate) were optimized for each newly constructed electrolytic cell. Under the optimal working parameters, the basic characteristics of selenium determination were found out by using electrochemical hydride generation. The electrolytic cells were compared to each other and with the classical electrolytic cell...
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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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Multicomponental Preconcentration of As, Sb, Se and Te on Modified Silica, Their Determination by ICP-AES (ICP-MS) and Application for Waters
Urbánková, Kristýna ; Řehůřková, Irena (referee) ; Kanický, Viktor (referee) ; Ventura, Karel (referee) ; Sommer, Lumír (advisor)
The determination of inorganic speciations of arsenic, antimony, selenium and tellurium in natural waters demands often separation and preconcentration. Solid phase extraction is a very effective method for these purposes. In this paper the separation and preconcentration of these microelements is realised on the basis of modified silica Separon SGX C18, SGX C8, SGX CN, SGX NH2, SGX Phenyl and strongly basic anion Exchanger SGX AX. The sorption was provided in the presence of cationic surfactants such as benzyldimethyl dodecylammonium bromide (Ajatin), benzyldimethyltetradecylammonium chloride (Zephyramine), 1-ethoxycarbonylpentadecyltrimetrhylammonium bromide (Septonex) and selected complexing agents 4-(2-pyridylazo)resorcinol (PAR), 8-hydroxyquinoline-5-sulphonic acide (8-HQS), 1,2-dihydroxybenzene (PYR), amonium 1-pyrrolidinecarbodithioate (APDC), sodium diethyldithiocarbamate (DTC) or thiourea(Thur). The interactions of the formed ion associate with the sorbent shows a complicated character which has not been cleared as yet. The previous conditioning of the sorbent plays an outstanding role. Thus, the sorption efficiency was studied in the presence and absence of surfactant and of selected organic complexing agents. Moreover, the influence of pH of the sorbed solution as well as the speed and the volume of the solution running through the sorbent and the type and volume of the eluent on the resulting sorption efficiency was evaluated. The sorption was successfully carried out from 50-1000 ml of solution which allows the 100 fold increase of the preconcentration factor and the determination of the microelements in g.l-1 instead of mg.l-1 by using the common ICP-AES. The influence of macroelements occurring in waters as well as B, Be, Bi, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sr, Ti, V and Zn in comparable concentrations involve less than 5% error. After the quantitative elution of microelements, the organic solvents were evaporated under IR lamps prior to the determination by ICP-AES and |ICP-MS. The conditions for the direct determination of arsenic, antimony, selenium and tellurium in g.l-1 with ICP-MS were also described in detail in the absence and presence of internal standards Ge and Bi. However, even in this case the preconcentration on silica in the presence of surfactant and selected organic complexants was also tested. When the sorption was followed from 500 ml a 50 fold enrichment factor is reached and the sensitivity for the microelements is improved. The direct determination and the sorption of microelements were applied on synthetic and real waters (dirinking, surface, mineral and sea waters). Instrumental and practical detection limits for various water samples were evaluated according to IUPAC. The results from 1000 ml solution of real waters after sorption on modified silica and the final determination of microelements with ICP-AES were compared with those from ICP-MS without sorption using the method of standards addition in the presence of suitable internal standards. By comparison of results for synthetic and real water samples the error of the determination of microelements was evaluated.
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Výzkum pro hospodaření s odpady v rámci ochrany životního prostředí a udržitelného rozvoje (prevence a minimalizace vzniku odpadů a jejich hodnocení): Vybrané odpady – autovraky a elektroodpad
Výzkumný ústav vodohospodářský T.G. Masaryka, v.v.i., Praha ; Hudáková, Věra
Sledování obsahu nebezpečných látek vyskytujících se v dosud nevyužitelných frakcích odpadů, které vznikají po zpracování odpadů z autovraků a elektroodpadů probíhalo v letech 2006 až 2011. Byla shromážděna data o sledovaných ukazatelích olova, kadmia, šestimocného chromu v odpadech ze zpracování autovraků a u elektroodpadů navíc i polybromovaných bifenylů, polybromovaných difenyléterů, arsenu, antimonu, berylia a selenu. Získané hodnoty byly vyhodnoceny statisticky a zhodnocen byl i vývoj obsahu jednotlivých kongenerů PBDE ve sledovaných odpadech. Jsou uvedeny poznatky o zpracovatelských technologiích, druzích plastů používaných v automobilech a elektrozařízeních a jejich zpracování, součástkách a v nich obsažených nebezpečných látkách.
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Výzkum pro hospodaření s odpady v rámci ochrany životního prostředí a udržitelného rozvoje (prevence a minimalizace vzniku odpadů a jejich hodnocení): Vybrané odpady – autovraky a elektroodpad. Subprojekt 6
Výzkumný ústav vodohospodářský T.G. Masaryka, v.v.i., Praha ; Hudáková, Věra
Je sledován obsah nebezpečných látek, které se vyskytují v dosud nevyužitelných frakcích odpadů, které vznikají z drcení autovraků a elektrozařízení a většinou končí na skládkách. Jedná se hlavně o odpady z výrobků, u kterých ještě nebylo směrnicemi EU při jejich výrobě používání těchto látek zakázáno. U odpadů z autovraků je sledován obsah Pb, Hg, Cd, CrVI. V odpadech z elektrozařízení jde o sledování obsahu Pb, Hg, CrVI, PBB, PBDE, které je na základě doposud používaných materiálů při výrobě rozšířeno o As, Be, Sb, a Se.
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Výzkum pro hospodaření s odpady v rámci ochrany životního prostředí a udržitelného rozvoje (prevence a minimalizace vzniku odpadů a jejich hodnocení): Vybrané odpady – autovraky a elektroodpad
Výzkumný ústav vodohospodářský T.G. Masaryka, v.v.i., Praha ; Hudáková, Věra
Je sledován obsah nebezpečných látek, které se vyskytují v dosud nevyužitelných frakcích odpadů, které vznikají z drcení autovraků a elektrozařízení a většinou končí na skládkách. Jedná se hlavně o odpady z výrobků, u kterých ještě nebylo směrnicemi EU při jejich výrobě používání těchto látek zakázáno. U odpadů z autovraků je sledován obsah Pb, Hg, Cd, CrVI, PBB, PBDE. V odpadech z elektrozařízení jde o sledování obsahu Pb, Hg, CrVI, PBB, PBDE, které je na základě doposud používaných materiálů při výrobě rozšířeno o As, Be, Sb, a Se. Byla navržena metodika stanovení těžkých kovů v přenosných elektrochemických článcích a připraven technický podklad pro sladění evidence odpadů ve vyhlášce č. 352/2005 Sb. s ostatními právními předpisy.
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