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Application of electrochemical methods for the determination of platinum metals
Vašátko, Jan ; Řezáčová, Veronika (referee) ; Komendová, Renata (advisor)
This bachelor thesis deals with the optimization of platinum determination conditions using electrochemical methods, namely voltammetric analysis. The theoretical part describes the physical and chemical properties of platinum and platinum group metals, their occurrence and their use. The theoretical part also deals with the toxicity of platinum group metals and their environmental cycles. Finally, other possible methods of determination are mentioned, including a detailed description of the voltammetric analysis. The experimental part describes the process of optimization of the conditions of voltammetric analysis of platinum and the application of the optimised method on real samples.
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Voltammetric Determination of Genotoxic 4-Nitroindane at Mercury and Silver Amalgam Electrodes
Burdová, Vendula ; Vyskočil, Vlastimil (advisor) ; Zima, Jiří (referee)
Presented Diploma Thesis is focused on electroanalytical determination of genotoxic 4-nitroindane, one of the nitrated polycyclic aromatic hydrocarbons (NPAHs). A hydrocarbon indane (a component of petrol) is a precursor of 4-nitroindane. NPAHs are produced all above by combustion processes in gasoline and diesel engines. It has been shown that NPAHs can be many times more mutagenic or carcinogenic than their parent PAHs, so the analysis of these dangerous pollutants becomes important for modern environmental analytical chemistry. Optimal conditions for determination of 4-nitroindane have been investigated in buffered water-methanolic solutions and electrochemical transformations of 4-nitroindane have been studied by DC voltammetry (DCV), differential pulse voltammetry (DPV) and cyclic voltammetry at a hanging mercury drop electrode (HMDE) and at a mercury meniscus modified silver solid amalgam electrode (m-AgSAE). For voltammetric determination of 4-nitroindane, the following techniques were used: DCV (limit of quantification (LQ) ~ 7. 10-8 mol. l-1 ), DPV (LQ ~ 1. 10-7 mol. l-1 ) and adsorptive stripping voltammetry (AdSV; LQ ~ 7. 10-9 mol. l-1 ) at HMDE, and DCV (LQ ~ 1. 10-7 mol. l-1 ) and DPV (LQ ~ 1. 10-7 mol l-1 ) at m-AgSAE. The applicability of the newly developed...
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Polarographic Determination of Genotoxic 2-Amino-9-fluorenone
Hájková, Andrea ; Dejmková, Hana (referee) ; Vyskočil, Vlastimil (advisor)
of Bachaleor Thesis The aim to this work was to find the optimum conditions for polarographic determination of genotoxic 2-amino-9-fluorenone (2-AFN) that can negatively affect the living and working environment. Foremost, the stability of 2-AFN stock solution in methanol was monitored using UV-VIS spectrophotometry and an optimal ratio of buffered aqueous and methanolic phase was found out for following polarographic measurements at a classical mercury dropping electrode (DME). The dependence of polarographic behavior of 2-AFN (of concentration 1×10-4 mol dm-3 ) on pH of analyzed solution was measured using DC tast polarography (DCTP) and differential pulse polarography (DPP) in the pH range 1.9 - 12.8, in the medium of Britton-Robinson (BR) buffer - methanol (9:1). The mechanism of polarographic reduction of electrochemically reducible oxo group at 2-AFN has been proposed on the basis of thus observed behavior. The optimum medium of BR buffer pH 4.0 - methanol (9:1) has been chosen for both polarographic techniques. The concentration range from 1×10-6 to 1×10-4 mol dm-3 was measured using DCTP at DME and from 1×10-7 to 1×10-4 mol dm-3 using DPP at DME. Reached limits of quantification (LQs) were 5×10-7 mol dm-3 and 1×10-7 mol dm-3 for DCTP at DME and DPP at DME, respectively. For comparison, the...
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Polarographic Determination of the Herbicide Aclonifen
Murcková, Klára ; Vyskočil, Vlastimil (advisor) ; Dejmková, Hana (referee)
This thesis deals with the differential pulse polarographic determination of the herbicide aclonifen and with the TAST polarographic determination of the herbicide aclonifen. A dropping mercury electrode was used as the working electrode. UV/VIS spectrophotometric detection was used for comparison to electrochemical detection, the walenghts used were 308 nm and 388 nm. Optimal pH conditions were determined for determination using TP, DPP and UV/VIS spectrophotometry. The calibration dependences were measured using the found optimal conditions and limits of quantification, and limits of detection were determined. Limit of quantification for aclonifen were found to be 3,4·10-6 mol·L-1 using TP; 2,2·10-7 mol·L-1 using DPP and 4,6·10-6 mol·L-1 using UV/VIS spectrophotometry.
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Electrochemical sensor for ascorbic acid detection
Hlavička, Michal ; Kynclová, Hana (referee) ; Majzlíková, Petra (advisor)
This work deals with electrochemical detection of ascorbic acid using screen-printed three-electrode sensors. The work is divided into three parts, where the first describes the theory of thick-film technology, including the types and compositions of the pastes, fabrication and firing. The second part deals with the methods, measurement principles and the electrochemical detection of ascorbic acid. Experiments were done using screen-printed carbon electrodes in a solution of phosphate buffer and ascorbic acid. In conclusion the results are evaluated.
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Thick-film sensors for heavy metals detection
Gajdoš, Libor ; Majzlíková, Petra (referee) ; Prášek, Jan (advisor)
This project describes the possibilities of heavy metals detections in solutions using differential pulse voltammetry with tree-electrode electrochemical thick-film sensors. In the theoretical part, the thick-film technology is described as well as thick-film pastes’ types and compositions, followed by introduction to electrochemistry and electro-analytical methods of measurement. This project also describes the three measured heavy metals – cadmium, lead and copper. In the practical part, heavy metals’ ions detection in solutions using carbon working electrode and determination of the detection limit and sensitivity are described and discussed. Finally the evaluation of obtained results and results comparison to hygienic limits are included.
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Polarographic analysis of water
Klečka, Tomáš ; Rozman, Jiří (referee) ; Čížek, Martin (advisor)
This bachelor's project creates the necessary theoretical foundation of polarography and voltametry in the first part, which is needed to successful measurement using these technics. In the second part there is realized measurement with anodic stripping voltametry and accomplished evaluation in MATLAB. Finally there is example of procedure for laboratory task with polarograph.
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Assessment of Potential Risk Connected with the Use of Mercury and Mercury Electrodes
Navrátil, Tomáš ; Švancara, I. ; Mrázová, K. ; Nováková, Kateřina ; Chýlková, J. ; Pelclová, D.
This contribution tries to asses critically the danger connected with utilization of mercury in different branches of human activites. The main attention was devoted to electrochemistry, mainly to voltammetry and polarography. However, to other branches were characterized as well: dentistry, in battery production, mining industry, and a few others. The most toxic and contarily almost nontoxic forms of mercury and of its compounds were characterized. Some interesting cases of exposure to mercury, according to the database of the Czech Toxicological Information Centre (TIC) (from years 1995-2011), have been reported,
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Electrochemical and spectrometric study of FOX-7 in aprotic solvents
Šimková, Ludmila ; Ludvík, Jiří ; Klíma, Jiří
2,2-Dinitroethene-1,1-diamine (FOX-7) is a recently developed and broadly tested energetic material with high efficiency and low sensitivity. Generally, explosion is based on thermally initiated chain of intramolecular redox reactions. Recently it has been found that electrochemical reduction in aqueous solutions is also able to provoke the chain of follow-up processes leading to total decomposition of the parent substance yielding gaseous products analogously like during explosion. Similarly, results from reductive electrolysis of FOX-7 in aprotic solvents show analogous course of degradation. The first transferred electron activates the molecule and initiated the formation of colored radical intermediates that have been spectroscopically characterized
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Development of the scope of polarography with time (review)
Heyrovský, Michael
The classical definition of polarography was "electrolysis with dropping mercury electrode (DME)". This definition characterized originally d.c. voltage-controlled method containing theoretical equations of different currents obtained with DME as well as its practical applications in analysis and in general science. Gradually, next to dropping electrode other types of mercury electrodes were used, as streaming and hanging drop. Development of the instrumental side of polarography introduced also methods of current-controlled electrolysis and beside pure mercury also amalgam electrodes. Nowadays polarography can be best characterized as physico-chemical branch of science ceveloped from simplke electrolysis with dropping mercury electrode.
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