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Voltammetric behaviour of cholesterol and lanosterol on boron doped diamond electrode
Kubešová, Jana ; Schwarzová, Karolina (advisor) ; Nesměrák, Karel (referee)
The aim of this thesis is to investigate procedures leading to regeneration of boron- doped-diamond's (BDD electrode) surface and study of voltammetric behaviour of cholesterol and lanosterol on BDD electrode. Three options of regeneration of electrode's surface were were studied: the stirring, the mechanical polishing using alumina and the anodic oxidation. The anodic oxidation was studied using electrolytes: 0,1 mol l−1 perchloric acid in acetonitrile, 0,1 mol l−1 sodium perchlorate in acetonitrile and tetrahexylammonium hexafluorofosphate in acetonitrile. Each electrolyte was studied with 0 or 0,43 % and 20 % volume of water. Further, voltammetric behaviour of cholesterol on BDD electrode in the presence of 0,1 mol l−1 perchloric acid in acetonitrile was investigate. The second part of the thesis was the study of voltammetric behaviour of lanosterol on BDD electrode in the presence of 0,1 mol l−1 perchloric acid in acetonitrile and 0,1 mol l−1 sodium perchlorate in acetonitrile. The study was performed using cyclic voltammery. Lanosterol provides two anodic signals in the presence of both electrolytes, the first one at the potential of +1200 mV, the second one at the potential of +1500 mV. The stability of lanosterol in the presence of perchloric acid and sodium perchlorate was studied by...
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Analysis of historical pharmaceutical preparation containing chicory from the 18th century
Lener, Tomáš ; Nesměrák, Karel (advisor) ; Kubíčková, Anna (referee)
A historical pharmaceutical preparation - chicory extract - from the 18th century whose authenticity was investigated was qualitatively analyzed using HPLC with UV/VIS and MS2 detection. A current dry chicory root was used as a source of selected chicory chemotaxonomic markers and an indicator of the success of extraction with different solvents. The authenticity of the historical extract was proved by a water solubility test. A VIS spectrometric determination of inulin was used and the inuline content was determined to be 52.4% in the current dry chicory root and 7.45% in the historical extract. The detection wavelength 254 and 320 nm was selected from measured UV/VIS spectra of selected standards and the literature. The authenticity of the historical chicory extract was proven by tandem mass spectrometry, and, moreover, arteincultone - a new chicory chemotaxonomic marker - was identified. Key words: HPLC-MS, HPLC-UV/VIS, UV/VIS Spectrometry, Chicory, Historical extract, Chicory root, Arteincultone
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Sequential Injection Analysis for Spectrophotometric and Spectrofluorometric Determination of Chlorpromazine, Levomepromazine and Promethazine
Kroiherová, Anna ; Nesměrák, Karel (advisor) ; Červený, Václav (referee)
In this diploma thesis, a method using the sequence analysis technique for spectrometric and spectrofluorimetric analysis of three selected analytes from the group of phenothiazines (chlorpromazine, levomepromazine and promethazine) was developed and optimized. The determination is based on the oxidation reaction of phenothiazines with cerium(IV) ions in an acidic medium, which produces a color product that is detected by VIS spectrometry or spectrofluorimetry. The measurement conditions for sequence analysis were optimized and evaluation was performed by nonlinear calibration in the dynamic range of 3−320 mg dm−3 for VIS spectrometric detection and 0.3−50.0 mg dm−3 for spectrofluorimetric detection. The influence of water-soluble common excipients (fructose, glucose, lactose), which are often part of medicinal products, was investigated. The developed sequential injection analysis with both detections was successfully applied to authentic samples of drugs (Plegomazine, Tisercine and Prothazine) containing the analyzed phenothiazines. The measurement results were in good agreement with the used reference method of direct UV spectrometry. The advantages of developed SIA method with VIS spectrometric and spectrofluorometric detection are its automation, speed, low consumption of reagent and a wide...
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Sorption of radionuclid 85Sr to soils from area nuclear power plant Temelín
Reidingerová, Markéta ; Nesměrák, Karel (advisor) ; Rychlovský, Petr (referee)
This thesis is focused on the study of sorption of radionuclide 85 Sr in soil collected in the area of a nuclear power plant Temelín. A single-batch method experiment was used when a solution of radionuclide 85 Sr of known activity was added to the soil. The experiments focussed on the influence of pH with the size of the sorption and the influence of the time of the contact of the solution with the sorption. During the experiment with the value of pH closest to the pH of underground water from the nuclear power plant Temelín, the sorption of soil was somewhere between 31 to 44 %. When the time influence on the sorption was examined, radionuclide 85 Sr was sorbed very quickly. For the comparison of the sorption size in connection with the time, for which it was chosen 120 minutes, the sorption was almost constant, reaching 40 to 48 %. Key words Radioactivity, radionuclide 85 Sr, sorption, nuclear power plant Temelín
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Electrochemical sensor with electrode modified by phthalocyanine derivative used for determination of sulfur compounds
Zlámalová, Magda ; Nesměrák, Karel (advisor) ; Navrátil, Tomáš (referee)
The diploma thesis presents the results of the studies of thin layer film composed of N,N',N'',N'''-tetramethyl-tetra-3,4-pyridinoporphyrazinocobalt. This film is deposited on the surface of highly oriented pyrolytic graphite. The modified electrode displayed electrocatalytic activity to oxidation of sulphide anions and cysteine. It has been studied the possibility of enhancement of stability of the immobilized film by the nafion. This electrode was used for the analytical determination of sulphide anions and cysteine. Keywords: highly oriented pyrolytic graphite, porphyrazines, hydrogen sulphide, cysteine, nafion, cyclic voltammetry, atomic force microscopy
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Testing of Polished Silver Solid Amalgam Composite Electrode for Voltammetric Determination of Environmental Pollutants
Dědík, Jan ; Vyskočil, Vlastimil (advisor) ; Nesměrák, Karel (referee)
The aim of this study was the finding of applicable conditions for the determination of selected model environmental pollutants, namely 5-nitrobenzimidazole and picric acid, using DC voltammetry (DCV) and differential pulse voltammetry (DPV) at a polished silver solid amalgam composite electrode (p-AgSAE-CE) in the aqueous solution of Britton-Robinson (BR) and finding of the limit of quantification (LQ) for these substances. For 5-nitrobenzimidazole, the optimum conditions of voltammetric determination have been found in the medium of B-R buffer pH 5, but any calibration dependences were obtained. The reason was the deteriorating quality of 5-nitrobenzimidazole response even if the routine pretreatment of working electrode was maintained. This resulted in obtaining of irreproducible results upon the determination of 5-nitrobenzimidazole. For picric acid, the optimum conditions have been found for both DPV and DCV at p-AgSAE-CE in the medium of B-R buffer pH 2. The concentration dependences were measured in the range 1.10-6 - 1.10-4 mol.L-1 for DPV with the value of reached LQ 2,5.10-7 mol.L-1 and, for DCV, in the range 1.10-7 - 1.10-4 mol.L-1 with LQ calculated as 5,5.10-8 mol.L-1 . For comparison of newly developed voltammetric methods of picric acid determination, a UV-VIS spectrophotometric...
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The Flow Injection Analysis of Procaine and Sulfamethoxazole with Spectrophotometric Detection
Baptistová, Adéla ; Nesměrák, Karel (advisor) ; Červený, Václav (referee)
A derivatization reaction, based on a copulation reaction of diazonium salt of an analyte with a reagent (1-aminonaphthalene or NEDA) producing colour, spectrophotometrically detectable product, has been used for determination of two analytes (procain hydrochloride, sulfamethoxazole) containing amino group in the molecule. The conditions of batch spectrophotometric determination were studied. It was found, that the batch determination is applicable only for procain hydrochloride analysis, because sulfamethoxazole gives time-unstable colour product. FIA arrangement was proposed and effects of selected parameters were optimized using two levels factorial design. The calibration dependences were measured for both analysis with both reagents, and subsequently were applied on determination of analytes in medical forms. Key words: diazotization, flow injection analysis, procaine, spectrophotometry, sulfamethoxazole
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