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Electrochemical Deposition of Silver Amalgam Particles on Pyrolitic Graphite Electrode
Šebest, Peter ; Havranová-Vidláková, Pavlína ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
Silver solid amalgam represents suitable alternative electrode material to metallic mercury, Controlled electrodeposition of variable silver amalgam particles (AgAP) on the surface of pyrolitic graphite electrode from an electrolyte containing Agt It and Hg(II) ions is reported as a novel method suitable lot preparation of perspective supporting materials Scanning electron microscopy including energy-disperse X-ray spectrometer and image processing software were used for analysis of composition and morphology of AgAP on POE A model electrochemically reducible 4-niirophenol was used to test a potential applicability of AgAp-PGE in electroanalytical methods.
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Preparation and Characterization of Silver Amalgam Particles on Gold Electrode Surface
Havranová-Vidláková, Pavlína ; Šebest, Peter ; Ligmajer, Filip ; Fojta, Miroslav ; Daňhel, Aleš
This work is focused on the preparation of silver amalgam particles by its direct electrodeposition on gold surfaces using double pulse chronoamperometry from solution containing soluble Ag+ and Hg2+ ionts. During the electrodepositions of silver amalgam particles, different: i) parameters of chronoamperometry, ii) Ag/Hg ratio in solution and iii) gold electrodes were studied. All the prepared amalgam particles were characterized by scanning electron microscope with energy dispersive X-ray spectroscopy and electrochemical methods. Voltammetric application of the gold electrodes decorated by sliver amalgam particles was confirmed by analysis of model organic nitrocompound using cyclic voltammetry.
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Silver Amalgam Electrodes in Electroanalysis of Selected Agrochemicals
Daňhel, Aleš ; Barek, Jiří (advisor) ; Vytřas, Karel (referee) ; Ludvík, Jiří (referee)
4 ABSTRACT Development and testing of novel non-toxic electrode materials, detection arrangements and analytical methods applicable in determination of selected agrochemicals is the main aim of this Ph.D. Thesis. New working electrodes based on silver solid amalgam paste (AgSA-PE) with organic pasting liquid and other based on crystallic silver amalgam (CAgAE) were developed, their electrochemical behaviour investigated and further used in voltammetric determination of widespread and toxic environmental pollutant 4-nitrophenol (4-NP). This analyte could be determined by DPV at AgSA-PE with limit of detection (LD) 1×10í6 mol lí1 and using CAgAE with LD 4×10í7 mol lí1 , both in 0.2 mol lí1 acetate buffer pH 4.8. Attempts to decrease LDs by utilization of adsorptive stripping voltammetry were not successful in either case. Crystallic silver amalgam was also successfully used for construction of microcylindric flow-through cell and tested for amperometric determination of nitrophenol mixture in HPLC-ED system. Both novel electrodes were found to be suitable alternatives to toxic mercury electrodes and the CAgAE seems to be promising working electrode for flowing systems. Method for sample preparation and voltammetric determination of broad-spectrum herbicide Glyphosate in contaminated soil samples was also...
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Silver amalgam electrodes in electroanalysis of selected agrochemicals
Daňhel, Aleš
Development and testing of novel non-toxic electrode materials, detection arrangements and analytical methods applicable in determination of selected agrochemicals is the main aim of this Ph.D. Thesis. New working electrodes based on silver solid amalgam paste (AgSA-PE) with organic pasting liquid and other based on crystallic silver amalgam (CAgAE) were developed, their electrochemical behaviour investigated and further used in voltammetric determination of widespread and toxic environmental pollutant 4-nitrophenol (4-NP). This analyte could be determined by DPV at AgSA-PE with limit of detection (LD) 1×10−6 mol l−1 and using CAgAE with LD 4×10−7 mol l−1 , both in 0.2 mol l−1 acetate buffer pH 4.8. Attempts to decrease LDs by utilization of adsorptive stripping voltammetry were not successful in either case. Crystallic silver amalgam was also successfully used for construction of microcylindric flow-through cell and tested for amperometric determination of nitrophenol mixture in HPLC-ED system. Both novel electrodes were found to be suitable alternatives to toxic mercury electrodes and the CAgAE seems to be promising working electrode for flowing systems. Method for sample preparation and voltammetric determination of broad-spectrum herbicide Glyphosate in contaminated soil samples was also...
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Determination of vanillin using carbon paste electrode
Jarošová, Romana ; Zima, Jiří (advisor) ; Daňhel, Aleš (referee)
Title: Determination of vanillin using carbon paste electrode. Abstract: The aim of this work is the determination of vanillin by flow injection analysis (FIA) with electrochemical detection using carbon paste electrode (CPE) and spectrophotometric detection. Optimal conditions for determination of vanillin by the FIA were found. Under optimal conditions calibration dependences were measured in the concentraction range from 1·10-4 mol·l-1 to 2·10-7 mol·l-1 . The calibration dependences were evaluated using linear regression method. Comparable results were achieved for the determination of vanillin by FIA with electrochemical detection using CPE and for the determination of vanillin by FIA with spectrophotometric detection. Limits of detection were identical 1.7·10-7 mol·l-1 . Key words: vanillin, carbon paste electrode, flow injection analysis, electrochemical detection, spectrophotometric detection
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Sodium cooled fast reactors
Daňhel, Aleš ; Katovský, Karel (referee) ; Foral, Štěpán (advisor)
This bachelor’s thesis deals with the sodium-cooled fast reactors. It comprehensively describes the problem of sodium-cooled fast reactors. Attention was paid to the basic specifications and parameters of these reactors. There was briefly described nuclear reactions which are under way in core of sodium-cooled fast reactors but also chemical reactions which are linked to function of liquid sodium as a coolant and heat transfer substance. Attention was also paid to the differences in the reactor core configuration and to the machine device specific for sodium-cooled fast reactors. Further on this bachelor’s thesis puts on the overview of sodium-cooled fast reactors that have worked, are still working or are under construction in each country all over the world. There was briefly described generation IV nuclear reactors, particularly its history and reasons that originate generation IV. Under generation IV was also described nuclear reactor SFR and highlighted differences compared to existing sodium-cooled fast reactors. In the practical part of this bachelor’s thesis is easily made a calculation of the heat transfer from the fuel rod to the cooling sodium and there is also mentioned course of the heat transfer coefficient along the fuel rod. This calculation was made by computing program MATLAB.
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Utilization of biomass for micro cogeneration
Daňhel, Aleš ; Šejvl, Radovan (referee) ; Baxant, Petr (advisor)
This master’s thesis deals with utilization of biomass for micro cogeneration. The theoretical part of the master’s thesis defines main terms of the master’s thesis, which is biomass and cogeneration. The practical part of the master’s thesis is focused on the design and manufacturing of small micro cogeneration unit based on a small membrane steam engine. It means design of two steam generators to produce steam for the membrane steam engine. It will be also carried out design and production of membrane steam engine which is fitted with a small BLDC generator including electrical part for power output and measuring parameters. It will be made several measurements with the steam engine including measuring power output characteristic of the steam engine and measuring loading characteristics of the generator.
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Searching for Electrochemical Reduction Mechanism of Azidophenyl DNA Labels
Daňhel, Aleš ; Trošanová, Zuzana ; Balintová, Jana ; Hocek, Michal ; Fojta, Miroslav
This contribution brings new information to sporadic scientific results concerned to electrochemical reduction of aromatic azides. Selected compounds used as perspective DNA labels or their structural constituents such as, 4-azidophenyltrifluoroboronic acid, 4-azidophenyl modified deoxycytidine and next probable analogous compounds and/or products of their reduction, were voltammetrically studied and compared to each other in order to reveal a mechanism of their electrochemical reduction at mercury electrodes in aqueous media. Preliminary results obtained by cyclic voltammetry at mercury and carbon based electrodes and by mass spectrometry of the products isolated from batch electrolysis on mercury pool by preparative chromatography are discussed.
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