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Voltammetric determination of drugs doxycycline and dimenhydrinate using carbon film electrode
Humpolíková, Jiřina ; Fischer, Jan (advisor) ; Dejmková, Hana (referee)
This bachelor's thesis concerns the determination of doxycycline (DX) and dimenhydrinate (DMH) by the methods DC voltammetry (DCV) and differential pulse voltammetry (DPV) on a carbon film electrode (CFE). The optimum conditions for voltammetric determination of DX and DMH were found and under these conditions, concentration dependences were measured and the limits of quantification (LOQ) were calculated for each method. The media of BR-buffer pH 12.0 was chosen as optimum for DCV and DPV determination of DX at CFE. For both DCV and DPV, the linear concentration dependences were obtained in concentration ranges of DX from 20 µmol·l-1 to 100 µmol·l-1 with LOQ 15,4 µmol·l-1 for DCV and 15,2 µmol·l-1 for DPV. DX was determined in drug using DCV under optimized conditions and for comparison of used voltammetric method DX in drug was determined also using UV-VIS spectrophotometry with consistent results. The optimum medium of BR buffer pH 3.0 was chosen for determination of DMH by DCV and pH 2.0 for DPV. The calibration range 2,0 - 10,0 µmol·l-1 of DMH was received using DCV and 0,2 - 1,0 µmol·l-1 of DMH was recevied using DPV at CFE with reached LOQ 0,08 µmol·l-1 for DCV and 0,02 µmol·l-1 for DPV. DMH was determined in comertional drugs using DCV on founded conditions. The stability of stock solution...
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Voltammetric Determination of 4-Nitrophenol at a Large-Surface Carbon Film Electrode
Šmejkalová, Hana ; Vyskočil, Vlastimil (advisor) ; Dejmková, Hana (referee)
The aim of presented Bachelor Thesis was to study an electrochemical behavior of 4-nitrophenol (4-NP) resulting in the founding of optimum conditions for its determination at newly prepared large-surface carbon film electrode (ls-CFE) using DC voltametry (DCV) and differential pulse voltammetry (DPV). Voltammetic behavior of 4-NP was investigated in dependence on the pH of the medium (realized using Britton-Robinson buffer). As optimum pH values for voltammetric determination of 4-NP at ls-CFE in cathodic potentials region, the pH values 6.0 (for DCV) and 7.0 (for DPV) were chosen. The determinations of 4-NP at ls-CFE (at a concentration of the analyte of 1·10-4 mol/l) showed a good repeatability for both voltammetric techniques used (2.2 % for DCV and 0.4 % for DPV). Therefore, the possibility of an electrochemical regeneration of the electrode surface has not been further investigated. Under optimum conditions, the calibration dependences of 4-NP were measured in the concentration range from 2·10-6 to 1·10-4 mol/l, with limits of quantification (LQ) of 2.3·10-6 mol/l (for DCV at ls-CFE) and 1.8·10-6 mol/l (for DPV at ls-CFE). The applicability of the newly developed methods of the determination of 4-NP was verified on the model samples of drinking water, with LQ of 1.0·10-6 mol/l (for DCV at...
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Voltammetric Determination of Chloramphenicol and Ofloxacin at Boron Doped Diamond Film Electrodes
Ječmínková, Jana ; Fischer, Jan (advisor) ; Vyskočil, Vlastimil (referee)
Voltammetric methods for the determination amphenicol antibiotic chloramphenicol (CAP) and quinolone antibiotic Ofloxacin (OFL) were developed. TTechniques differential pulse voltammetry (DPV) and DC voltammetry (DCV) for determination of both substances at boron doped diamond film electrode (BDDFE) were used. The effect of pH of Britton-Robinson buffer was tested and the stability of the signal with repeated measurements was monitored. Optimal pH 6 was used for determining of CAP by both, DPV and DCV techniques. Media of pH 4 for determining of OFL by DPV and DCV was optimal. Under these conditions linear dependences in the calibration concentration region 1.10 -6 - 1.10-4 mol.l -1 were obtained. The limit of determination for the method for CAP by DPV at 3.10 mol.l , by -6 -1 DCV at 3.10 mol.l and for -6 -1 OFL by DPV at 1.10 mol.l -6 -1 and by DCV at 4.10 mol.l -7 -1 was found. The developed methods were used for the determination of CAP in the drug samples Spersadex comp. and OFL determination in drug samples Zanocin 200. Method for solid phase extraction of OFL from samples of urine with voltammetric detection was developed with limit of determination at 7.10 mol.l . -6 -1
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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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Difference pulse voltametry for detection of metallothionein
Postránecká, Tereza ; Prášek, Jan (referee) ; Provazník, Ivo (advisor)
Metallothionein (MT) is a protein with a characteristic amino acid composition which thanks to its thiol groups can bind metal ions and be involved in the homeostasis of these ions in organism. The protein has its significance in carcinogenesis, could be a suitable marker for certain types of tumors. MT has many specific functions in organisms. It can be studied using several techniques. In common use electroanalysis is used as method for determining the concentration of MT. More specifically, this work is focused on differential pulse voltammetry using Brdička reaction.
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Carbon nanotubes utilization for fabrication of thick-film sensors electrodes
Polický, Jiří ; Adámek, Martin (referee) ; Prášek, Jan (advisor)
This work covers an area of heavy metals detection by miniaturized thick film sensors. Working electrode of these sensors was fabricated using thick film paste that was prepared as a nanocomposition of carbon nanotubes powder, suitable vehicle and a thinner. The response of fabricated electrodes to cadmium and lead ions was measured using differential pulse voltammetry in an acetate buffer solution using a three electrode sytem. The results were compared with the carbon electrode made from special commercial thick film polymer paste. Finally the possibility of working electrode surface activation with nitric acid and heavy metals on real biological sample detection is described here.
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Selected inorganic pollutants in foodstuffs
Kroupová, Kateřina ; Vítová, Eva (referee) ; Vitoulová, Eva (advisor)
This bachelor thesis is focus on occurrence of inorganic pollutants in foodstuffs. The introduction is dedicated to apperance of individual selected elements in foodstuffs. Concentration of these elements is very important factor for examination of toxic effects for the human organism. If we want to avoid the harmful effects to the human organism, we have to define border limits. Work is based on the legislative of Czech republic. Second part of this study is focused on the biological monitoring. The biological monitoring is important for precautionary measures. In the third part of this study are described toxical effects of these elements to the human organism. Before qualitative and quantitative analysis by instrumental techniques is important to properly take the sample. In the fourth and fifth part of this work are mentioned methods used for determination of these elements and metods of taking samples. This bachelor thesis provide complex view on the problems of pollutants in foodstuffs and it should be used as a base for following diploma thesis.
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Studium vlivu těžkých kovů na biochemický profil u vodních živočichů
Šanda, Radek
This work deals with study of thiol compounds (metallothionein) and the determination of its quantity in the tissues of rainbow trout (Oncorhynchus mykiss). This tissues of the fish were exposed to several concentrations of arsenic. Concentration of metallothionein was measured elektrochemically by using differential pulse voltametry (DPV) by using Brdička's reaction. Metallothionein, which is among the low molecular weight thiols has very strong detoxication effects. Determining of the concentration of this protein could be used to determine the quality and also the health of fish meat.
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