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Elimination Voltammetry with Linear Scan: Advantages and Disadvantages
Navrátil, Tomáš ; Trnková, L. ; Hrdlička, Vojtěch ; Li, X.
Elimination voltammetry with linear scan (EVLS) represents an almost traditional\nmathematical method that helps to obtain additional and detailed information about the recorded\nelectrochemical signals and therefore, to better understand the analyzed systems. Although it\nhas been substantially developed and expanded during its existence of more than a quarter of a\ncentury and has found many areas of application, like any other mathematical and experimental\nmethod, it exhibits several advantages and disadvantages. In this contribution, we summarize\nits strengths, weaknesses, opportunities, as well as threats.\n
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Electrochemical Techniques in Monitoring of Nervous System Drugs
Choińska-Mlynarczyk, Marta ; Hrdlička, Vojtěch ; Skopalová, J. ; Šelešovská, R. ; Kolivoška, Viliam ; Navrátil, Tomáš
Drugs of the nervous system (ATC group N) belong generally to the most commonly (mis)used substances worldwide. Their determination and monitoring of these drugs and their metabolites in various body fluids or environmental matrices represent a challenge for analytical chemists. Our research is focused on the application of electrochemical methods in the monitoring of the most frequently prescribed and the newly introduced nervous system drugs of precisely specified structures and/or of defined properties. For toxicological and pharmacokinetic reasons, emphasis has been placed on investigating the reaction mechanisms of their metabolite formation. New or alternative to commonly used electroanalytical methods applicable for monitoring and characterization of target compounds in their pure state, in body fluids, wastewaters, and other environmental matrices, has been developed. To improve the chemometric parameters and sensing characteristics, attention was paid to the construction of new electrochemical sensors, detectors (e.g. screen-printed, 3D printed), or cells, based on (modified/unmodified) traditional or nontraditional materials, preferably usable at the point-of-care.
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Determination of heavy metal poisoning antidote 2,3-dimercapto-1-propanesulfonic acid using silver solid amalgam electrode
Choińska-Mlynarczyk, Marta ; Hrdlička, Vojtěch ; Redondo, B. R. ; Barek, J. ; Navrátil, Tomáš
2,3-Dimercapto-1-propane-sulfonic acid (DMPS) was investigated using direct current voltammetry (DCV), differential pulse cathodic stripping voltammetry (DPCSV), differential pulse anodic stripping voltammetry (DPASV), and elimination voltammetry with linear scan (EVLS) at a polished (p-AgSAE)and at a meniscus modified silver solid amalgam electrode (m-AgSAE). EVLS confirmed two consecutive reductions with coupled proton/electron transfer. Voltammetric titrations of DMPS with Pb2+ proved complex formation, with limits of quantification (LOQs) and detection (LODs) 0.3 and 0.1 mu mol L-1 at m-AgSAE and 0.8 and 0.3 mu mol L-1 at p-AgSAE, respectively. Determination of DMPS in commercial drug Dimaval and human urine samples confirmed practical applicability of the developed method.
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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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