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Thick-film sensors for heavy metals detection
Polický, Jiří ; Adámek, Martin (referee) ; Prášek, Jan (advisor)
This work covers an area of heavy metals detection using thick-film sensors. Fabrication of screen-printed thick-film sensor and electrochemical analytical methods for detection of chemical elements in aqueous solutions are described in this work. Several commercial and own prepared thick-film pastes were used for carbon based working electrodes. The electrochemical properties of the pastes were examined by cadmium ions detection in potassium chloride solution using differential pulse voltammetry. The best results were achieved on the electrode made of direct grown carbon nanotubes on the electrode layer NM22. A detection limit 20×10-6 mol l-1.was reached with this working electrode material during oxidation process.
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Influence of liposomal platinum cytostatics on cancer cells – voltammetric study
Laníková, Petra ; Prášek, Jan (referee) ; Hynek, David (advisor)
Aim of this thesis is voltammetric study influence of liposomal platinum cytostatics on cancer cells. One of the goals is summarize available informations about influence of cisplatine on cancer cells, its encapsulation into liposome and affection of this cytostatic cisplatin encapsulated in liposome on cancer cell lines. In literary recherche is detail description of these issues. Than is there specification of voltammetric methods, which serve to electrochemical detection of cisplatin. Based on literary recherche was chosen the best method for detection and subsequently the method was optimalized and than was applied to measuring itself.
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Study of influence of quantum dots to biological systmes and their components
Koudelková, Zuzana ; Zítka, Ondřej (referee) ; Provazník, Ivo (advisor)
The aim of this thesis is to summarize the available evidence about quantum dots and their effects on living systems. The text describes methods for the preparation of quantum dots with respect to their characteristics (size, fluorescence wavelength) and methods of quantum dots bio-functionalization of biomolecules. In living organisms is a large number of proteins, because these are considered as one of the main components of the interaction of organisms. Therefore, the work also provides basic information about proteins. Finally, there are described various methods by which the quantum dots may be characterized mainly by differential pulse voltammetry measurement zeta potential and fluorescence measurement. The main objective of this work is to propose models of different environments in which will be degradation of quantum dots with regard to the evaluation of acquired kinetic parameters for predicting the stability of individual quantum dots.
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Voltammetric Determination of Dinitronaphthalenes Using Single Crystal Silver Amalgam Electrode
Tvrdíková, Jana ; Barek, Jiří (advisor) ; Dejmková, Hana (referee)
Voltammetric methods for determination of 1,3-dinitronaphthalene (1,3-DNN), 1,5-dinitronaphthalene (1,5-DNN) and 1,8-dinitronaphthalene (1,8-DNN) using DC voltammetry (DCV) and differential pulse voltammetry (DPV) at novel single crystal silver amalgam electrode (CAgAE) were developed in this work. Developed methods may be used for determination of 1,3-DNN within a concentration range 2 - 10 μmol.L-1 with LoQ 2 μmol.L-1 using DCV and 1 - 100 μmol.L-1 with LoQ 1 μmol.L-1 by DPV; 1,5-DNN wihin a concentration range 2 - 10 μmol.L-1 with LoQ 2 μmol.L-1 using DCV and 1 - 10 μmol.L-1 with LoQ 1 μmol.L-1 by DPV and 1,8-DNN within a concentration range 2 - 10 μmol.L-1 with LoQ 2 μmol.L-1 using DCV and 0,3 - 1 μmol.L-1 with LoQ 0,3 μmol.L-1 by DPV. An attepmt to decrease LoQ by adsorptive stripping differential pulse voltammetry was not successful. Process of electrochemical reduction of selected dinitronaphthalenes on the working electrode was also studied by cyclic voltammetry. This work verified the use of CAgAE as alternative electrode material to mercury electrodes for determination of electrochemically reducible organic compounds in aqueous-methanolic media. Small dimensions of the CAgAE are the main advantages which predetermine its use in voltammetric microvolume batch analysis and amperometric detection in...
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Voltammetric Determination of 5-Nitrobenzimidazole Using Non-Traditional Electrode Materials
Chládková, Barbora ; Vyskočil, Vlastimil (advisor) ; Zima, Jiří (referee)
5 Abstract This Diploma Thesis is targeted on the determination of 5-nitrobenzimidazole (5-NBIA) using following techniques: DC voltammetry (DCV) and differential pulse voltammetry (DPV). As working electrodes, a silver amalgam paste electrode (AgA-PE), which was constructed for this determination in the form of a new prototype, a bismuth film electrode (BiFE), at which the optimum conditions for the deposition of the bismuth film at a suitable substrate (glassy carbon electrode and gold electrode were tested for this purpose) were initially optimized, and a glassy carbon electrode (GCE) were used. The optimum conditions for the voltammetric determination of 5-NBIA at the AgA-PE (in a medium of Britton-Robinson buffer (BR-buffer) of pH 7.0 for both DCV and DPV), at the BiFE with gold substrate (BR-buffer of pH 9.0 for both DCV and DPV; the film was deposited "ex situ" in a stirred plating solution (1000 mg L-1 Bi(III) solution in 0.1 mol L-1 acetate buffer of pH 4.5) for 300 s), and at the GCE (BR-buffer of pH 5,0 for both DCV and DPV). Under these conditions, calibration dependences were measured in the concentration ranges of 0.1 - 100 µmol L-1 (pro DCV a DPV na AgA-PE) and 1 - 100 µmol L-1 (pro DCV a DPV na BiFE a GCE), and the limits of quantification (LQs) were calculated for particular methods: LQ ≈...
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Determination of Lead Using FIA Technique with Spectrophotometric and Electrochemical Detection
Hála, Petr ; Vyskočil, Vlastimil (advisor) ; Rychlovský, Petr (referee)
The aim of this thesis was the determination of lead in water samples using complexating reaction with 4-(2-pyridylazo)-resorcinol in medium of 2-amino-2- hydroxymethyl-propan-1,3-diol hydrochloride buffer (Tris·HCl). Firstly, for the determination was chosen UV/VIS molecular spectrometry in a static arrangement. Subsequently, the method was performed in flow injection arrangement. The calibration was performed under optimal experimental conditions. The limits of detection for static and flow injection arrangements were 0.097 mol dm-3 and 0.27 mol dm-3 , respectively. Secondly, the determination of lead by differential pulse voltammetry was performed. The electrochemical properties of lead complex were investigated. During these experiments it was found out that small amount of this complex was adsorbed on the surface of silver solid amalgam electrode. The calibration was performed, the limit of detection was 0.020 mol dm-3 . Keywords Lead, 4-(2-pyridylazo)-resorcinol, flow injection analysis, UV/VIS molecular spectrometry, differential pulse voltammetry, silver solid amalgam electrode.
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Voltametric Determination of 4-Nitrophenol at a Bismuth Film Electrode
Hausner, Jiří ; Barek, Jiří (advisor) ; Dejmková, Hana (referee)
This Bachelor Thesis is focussed on the study of electrochemical behaviour of 4-nitrophenol (4-NP) and the search for optimal conditions for its voltammetric determination at a bismuth film-modified gold electrode (BiF-AuE). Voltammetric behaviour of 4-NP (c = 1×10-4 mol L-1 ) was investigated using direct current voltammetry (DCV) and differential pulse voltammetry (DPV) in dependence on the pH of the medium used (Britton-Robinson buffers). For both techniques, Britton-Robinson buffer of pH 7.0 was chosen as the optimum medium. Repeatability of the determination of 4-NP (c = 1×10-4 mol L-1 ) was 0.6 % and 0.9 % for DCV and DPV, respectively. Calibration dependences of 4-NP were measured in the concentration range from 1×10-6 to 1×10-4 mol L-1 under the optimum conditions. Attained limits of quantification (LQs) were 7.6×10-7 mol L-1 and 1.5×10-6 mol L-1 for DCV and DPV, respectively. The applicability of the newly developed voltammetric methods for the determination of 4-NP was verified on model samples of drinking water with LQ 7.5×10-6 mol L-1 for DCV at the BiF-AuE and 1.4×10-6 mol L-1 for DPV at the BiF-AuE.
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Voltammetric and amperometric detection of genotoxic pyrene derivatives at boron-doped diamond film electrode
Yosypchuk, Oksana ; Barek, Jiří (advisor) ; Nesměrák, Karel (referee)
This thesis is concentrated on the optimization of conditions for determination of genotoxic environmental pollutants whitch belong to derivatives of polycyclic aromatic hydrocarbons − 1-nitropyrene (1-NP), 1-aminopyrene (1-AP) and 1-hydroxypyrene (1-HP). All three compounds were determined by differential pulse voltammetry (DPV) at boron-doped diamond film electrode in water-methanolic solutions. Further, 1-AP and 1-HP were determined in a model sample of urine. For this purpose, effective separative techniques such as solid phase extraction and high performance liquid chromatography with reverse phase and amperometric detection at above mentioned type of electrode were used. Limits of detection of all tested compounds in water-methanolic solutions are 9⋅10−8 −3⋅10−7 mol dm−3 using DPV and 1⋅10−8 mol dm−3 for 1-HP and 1-AP in model sample of urine determined by HPLC with amperometric detection.
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Voltammetric determination of benzophenone-3 at carbon paste electrode
Molitor, Vít ; Zima, Jiří (advisor) ; Navrátil, Tomáš (referee)
A method for analysing benzophenone-3 on carbon paste electrode was developed. As a solvent a mixture Britton-Robinson buffer and methanol was used. The pH value of 12 was determined as optimal for further measurements. It was also found out that methanol added to the analyte solution did not negatively influence the voltammetric measurement. To decrease the limit of benzophenone-3 determination the accumulation of the analyte in the electrode surface was studied. The accumulation time of 300 seconds and accumulation potential of +400 mV were used as optimal. When measured under optimal coniditions the limit of detection was 6×10-7 M in deionised water and 5,5×10-7 M in drinking water. Real sample was measured using differential pulse voltammetry and spectrophotometry.
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Voltammetric and amperometric determination of homovanillic, vanillylmandelic, and 5-hydroxyindole-3-acetic acid
Němečková, Anna ; Barek, Jiří (advisor) ; Labuda, Ján (referee) ; Skopalová, Jana (referee)
Presented dissertation thesis is focused on the development of electrochemical methods for the determination of three important tumour biomarkers, namely homovanillic acid (HVA), vanillylmandelic acid (VMA), and 5-hydroxyindole-3-acetic acid (5-HIAA). First part of the study is focused on electrochemical behaviour of these analytes in batch arrangement using differential pulse voltammetry (DPV) at screen-printed carbon electrodes (SPCEs). It has been proved that presented method is sufficiently sensitive for monitoring above mentioned analytes. Moreover, it can be used for determination of HVA and VMA in mixture. Obtained limits of detection (LODs) were 0.24 µmol·L-1 for HVA, 0.06 µmol·L-1 for VMA, and 0.12 µmol·L-1 for 5-HIAA. The requirements to speed up the analysis and at the same time to reduce its price initialized our study of the determination of tested biomarkers in flow systems. Firstly, flow injection analysis with amperometric detection was investigated for the determination of all three biomarkers at the same SPCE, and then an analogous determination of structural more similar pair, HVA and VMA, was performed at a boron doped diamond electrode (BDDE). Obtained LODs of optimized methods were as follows: at SPCE 0.07 µmol·L-1 for HVA, 0.05 µmol·L-1 for VMA, and 0.03 µmol·L-1 for 5-HIAA,...
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