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Voltammetric Determination of Heavy Metals in Honeybee Venom using Hanging Mercury Drop Electrode and Carbon Conductive Filaments for 3D Printer
Navrátil, Tomáš ; Choińska-Mlynarczyk, Marta ; Šestáková, Ivana ; Hrdlička, Vojtěch
Heavy metals belong to typical contaminants of our environment. It is known that they are\nmetabolized and incorporated into bee products as honey as well as honeybee venom (apitoxin).\nIt is supposed that their composition can reflect contamination of the “bee environment” and\ncan give us information about the environment in the neighborhood of human dwellings.\nThis study aimed to develop a simple method for the determination of heavy metals in honeybee\nvenom. Due to the complicated matrix, wet microwave mineralization with sulfuric acid, nitric\nacid, under increased temperature and pressure, and repeated boiling with concentrated nitric\nacid had to be applied. Voltammetry proved to be very suitable for the determination of heavy\nmetals.\nTwo types of working electrodes have been used: pen-type hanging mercury drop electrode and\ncarbon conductive filaments for 3D printers. Results achieved using both of them and their\nadvantages and limitations have been compared.
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Determination of Selected Drugs using 3D Printed Electrodes
Choińska-Mlynarczyk, Marta ; Hrdlička, Vojtěch ; Navrátil, Tomáš
The main aim of this research was to develop a new method for voltammetric determination of\npopular antidepressants, analgesics, and illicit drugs using a laboratory-made 3D printed\nelectrode and to compare the achieved results with those registered using a commercially\navailable glassy carbon electrode. These experiments represent the first step in the development\nof a method applicable in clinical and forensic praxis for the rapid and inexpensive\ndetermination of commonly misused groups of biologically active compounds.
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The use of Boron Doped Diamond Electrode for Determination of 5-hydroxyindoleacetic Acid
Hrdlička, Vojtěch ; Navrátil, Tomáš
A new method for voltammetric determination of clinical biomarker 5-hydroxyindoleacetic\nacid (HIAA) at the boron-doped diamond electrode (BDDE) was developed. Anodically and\ncathodically pretreated BDDEs were tested in the pH ranges from 1 to 12, pre-treatment at\n+2.0V/60 s, and pH 3 was found to be the optimum.\nThe optimum square wave voltammetry (SWV) parameters were: f = 12 Hz, amplitude 60\nmV, and potential step 4 mV. SWV concentration dependency was constructed in the range\nfrom 0.1 to 100 μmol L−1, limits of determination and detection were 0.3 and 0.1 μmol L−1,\nrespectively. HIAA oxidation electrode process at BDDE was diffusion-controlled, as\nuncovered by cyclic voltammetry. Interestingly, HIAA peak potential was constant in various\nranges of pH, indicating a non-Nernstian behavior at the BDDE, in contrast to a previously\npublished electrooxidation mechanism consisting of a coupled H+/e− transfer.
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3D printed materials for the electrochemical determination of biologically active compounds
Choińska, Marta Katarzyna ; Navrátil, Tomáš ; Hrdlička, Vojtěch
3D printing materials are relatively novel materials in electrochemistry,\nused for manufacturing of electrochemical cells, electrodes\netc. They have been widely used mainly for tailored, fast, inexpensive,\nand easy preparation of various equipment for analyses of\nbiologically active compounds. Various medicinal products and illicit\ndrugs belong to this broad group of analytes which need to be\nmonitored because of the possibility of (un)intentional overdose or\nrecreational consumption, which can cause serious side effects or\neven death. Due to this risk, we decided to focus our research on the\ndevelopment of new, sensitive, selective, and easily customizable 3D\nprinted sensors for the determination of some commonly used\nantidepressants, analgesics, and illicit drugs.
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The History of Waldsassen Abbey since its Foundation to 1420 in Relation to Rulers of Bohemia and to the Cistercian Order
Hrdlička, Vojtěch ; Zdichynec, Jan (advisor) ; Bobková, Lenka (referee)
Annotation/Abstract: This bachelor thesis deals with the history and the development of cistercian abbey in Waldsassen since its origin in 1133 to 1420. This year is upper time limit of this thesis. This thesis should cover the reasons of foundation of this monastery, its imfluence, power in the Cheb region and his financial and economic relations and also changes inside monastic community. Important are social relations among particular members of the convent, especially part of the abbot like director of the monastery is pointed out. Author attempted to show connections of abbey in politics and participation off its members in the forming of history of Central Europe. Although Waldsassen was active in the Holy Roman Empire and developed its relations with the territories of Empire (Bavaria, Upper Palatinate, Egerland), it had the connections to the lands of the Crown of Bohemia and their rulers as well. It is the reason, why the most extensive chapter of this thesis is the fourth one about own history of abbey, the fifth one describes the relations of monastery with the czech sovereigns, but the connections of rulers of lands of the Crown of Bohemia were usually more feeble than these with the rulers of Roman empire.
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Electrochemical studies of the analytical utilization of self-assembled monolayers of calix[4]arene on the surface of polycrystalline gold electrode
Hrdlička, Vojtěch ; Navrátil, Tomáš (advisor) ; Ludvík, Jiří (referee)
This MSc. Thesis deals with electrochemical studies of the analytical utilization of self-assembled monolayers of thiolated calix[4]arene (C4A) and/or undecanthiole (C11SH) on the surface of a polycrystalline gold electrode. Hydroquinone, nitrobenzene, 2-nitrophenole and 4-nitrophenole have been used as tested model compounds. The real surface area of the electrode was determined using these two methods: From the charge of desorption peak of α-gold oxides (5.72±0.48 mm2 ) and using the Randles- Ševčík equation. (6.14±0.59 mm2 ). The preparation of the electrode consisted of polishing on alumina, immersing into piranha solution and cyclic voltammetry. The area of electrode surface was well reproducible. Stability of thiol monolayer in the area of negative potentials was tested. The C11SH layer is very stable; the desorption peak was recorded in basic solutions only (at −1.3 V vs. 3M Ag/AgCl). The position of the desorption peak of C4A is more pH dependent and it was recorded at −1.08 V at pH 13. The properties of the electrode modified by C11SH and or C4A were investigated using the model compound hydroquinone. It is assumed that the oxidation of the hydroquinone does not take place inside the C4A cavity; hence the hydroquinone molecule is too big to pass through the cavity. C11SH and C4 + C11SH act...
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The Beginnings of the Independent Czech Provincialate of the Augustinian Eremites Order in the Saint Thomas Monastery from 1604 to cca 1650
Hrdlička, Vojtěch ; Hojda, Zdeněk (advisor) ; Zdichynec, Jan (referee)
Annotation/Abstract: This thesis has aim to express and define circumstances the establishment of the independent Bohemia province of the order of St. Augustin in 1604 and its development to the end of Thirty Years War. The main emphasis will be put in the constructing of adminstration of new province and in personality of Jan Svitavský z Bochova, the first adminstrator. In view, that residence of the provincialate was the St. Thomas convent in Malá Strana, is necessary to point out the importance of this order convent and describe its dual role: first like seat of administrator, the second like the most important convent among other Augustinian convents of Land of the Crown of Bohemia with respect for its political and cultural significance. The author concentrates on relationships between administrator and convent of St. Thomas in Prague, and particular convents with their priors. Among important aims of thesis will be the discovery, how large autonomy of Augustinian convents was in Czech province and what their relation was with administrator, then detect relationships of administrator to general prior in Rome and papal curia. The establishment of independent Czech province in 1604 has of course connections with first re-Catholization attemps and with the position of St. Thomas convent in complicated...
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New approaches for voltammetric determination of tumour biomarkers and antidotes in urine
Hrdlička, Vojtěch ; Barek, Jiří (advisor) ; Novotný, Ladislav (referee) ; Skopalová, Jana (referee)
This Ph. D. thesis presents new methods for the determination of selected clinically relevant electrochemically active compounds. The first part deals with development of determination of tumour biomarkers homovanillic acid (HVA) and vanillylmandelic acid (VMA) in human urine with the use of hollow-fibre based liquid-phase microextraction (HF-LPME) and differential pulse voltammetry (DPV) at cathodically pre-treated boron doped diamond electrode (BDDE). Optimum conditions for HF-LPME-DPV of HVA and VMA were as follows: butyl benzoate as supported liquid membrane formed on porous polypropylene hollow-fibre, 0.1 mol L−1 HCl as donor phase and 30 min extraction time. Optimum acceptor phases were 0.1 mol L−1 phosphate buffer of pH 6 with ionic strength set to 0.55 mol L−1 for HVAand 0.1 mol L−1 NaOH for VMA, respectively. HF-LPME-DPV concentration dependencies for HVA and VMAwere linear in the range from 0.4 to 100 µmol L−1 and 0.5 to 100 µmol L−1 . Limits of quantification (LOQ)/detection (LOD) were 1.2/0.4 µmol L−1 for HVA and 1.7/0.5 µmol L−1 for VMA, respectively. The applicability of the developed methods was verified by analysis of human urine. In the second part, voltammetric behaviour of heavy metal poisoning antidote 2,3- dimercapto-1-propane-sulfonic acid (DMPS) was investigated with the use...
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The Waldsassen Abbey between Kingdom of Bohemia and Holy Roman Empire. The Political, Economic and Social Development of the Abbey and Its Manor in the 15th Century
Hrdlička, Vojtěch ; Zdichynec, Jan (advisor) ; Charvátová, Kateřina (referee)
The goal of this thesis was to analyse the development of abbey in Waldsassen since the end of 14th century to the finish of George's of Podiebrad reign. Author struggled to describe on the basis of analysis of above all unpublished monastic sources, which are deposited in State archive in Amberg, various aspects of life in Waldsassen convent. Apart from the economic base and its changes, which are well covered by amount of sources, also social a political relations to secular power in the Holy Roman Empire - roman rulers and princes are studied. Then the basis deals with contacts of monastery with the Crown of Bohemia and its aristocracy and also with the position of Waldsassen in the Order and its cooperation with other Cistercian monasteries. Matters dealt with the papal throne are not forgetten, too. Detailed analysis was dedicated to parish network and the land register of Waldsassen, which presents the valuable source for former economic relationships and toponyms of "Stiftland" and Upper Palatine. The fourth chapter is also comprehensive, describing Waldsassen during the Hussite wars and eliminates some myths about this period in the region. Closing parts of this thesis are dedicated to the renewal of abbey domain and to the effort, which was invested mutually to maintain good relations...
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