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Information System Assessment and Proposal of ICT Modification
Krätzer, Jan ; Novák, Lukáš (referee) ; Koch, Miloš (advisor)
This bachelor thesis deals with the assessment of the current situation of the information system of the company and it also focuses on the proposal of changes of this system in order to provide users more comfortable and faster work by its usage. The assessment of information system is based on the analysis and consultations with the firm's employees. The result of the solution was accepted by the CEO and the changes were valued as very beneficial.
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Photochemical generation of volatile species of nickel for analytical atomic spectrometry methods
Šoukal, Jakub ; Musil, Stanislav (advisor) ; Kratzer, Jan (referee)
This thesis deals with optimization of conditions of photochemical generation of volatile species of nickel for atomic absorption spectrometry. The volatile species of nickel were generated in the flow arrangement, when sample was injected to a stream of a reaction medium. Either formic acid was used as the reaction medium or formic acid with the addition of formate anions. Two types of a generator were tested, a generator with a PTFE tube wrapped around a mercury UV lamp and a high efficiency generator with an inside channel. At the same time, two types of a gas-liquid separator were tested. Diffusion flame was used as an atomizer due to its high robustness. Quartz atomizer didn't provide higher sensitivity and measurements had worse repeatability. All the parameters affecting atomization in the diffusion flame were optimized (flow rates and composition of gases, observation height). In the next section, conditions of generation (irradiation time, HCOOH concentration, addition of formate anions) were optimized. Interferences of inorganic acids in photochemical generation were investigated as well. It was found out that the generator with the inside channel provided slightly higher sensitivity and thus generation efficiency than the generator with the PTFE tube wrapped around. Transmission of...
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HG-AAS with atomization in a dielectric barrier plasma discharge: method optimization and analytical applications
Zurynková, Pavla ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
The aim of this diploma thesis was to optimize in detail atomization conditions for antimony hydride in a novel plasma atomizer based on a dielectric barrier discharge (DBD) with atomic absorption spetrometric detection. Argon was found as the best DBD discharge gas employing a flow rate of 50 ml min-1 Ar while the DBD power was optimized at 30 W. Analytical figures of merit including interference study of As, Se and Bi have been subsequently investigated and the results compared to those found in an externally heated quartz tube atomizer (QTA). The limit of detection reached in DBD (0.15 ng ml-1 Sb) is comparable to that observed in QTA (0.14 ng ml-1 Sb). Finally, possibility of stibane preconcentration in a DBD atomizer was studied. Preconcentration efficiency of 102 ± 6 % was found under optimized conditions.
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Application of a dielectric barrier discharge plasma atomizer to hydride generation atomic absorption spectrometry (HG-DBD-AAS)
Albrecht, Michal ; Kratzer, Jan (advisor) ; Červený, Václav (referee)
Atomization of plumbane in a novel dielectric barrier discharge (DBD) plasma atomizer has been optimized employing detection by atomic absorption spectrometry. The performance of the DBD atomizer was subsequently compared to that of a conventional externally heated quartz tube atomizer (QTA). Lead from a standard solution was converted to plumbane by chemical reduction with sodium borohydride using an identical hydride generator for both atomizers. Argon at a flow rate of 175 cm3 min-1 was found as the best discharge gas while the DBD power supply rate was optimized to 22 W. The inner surface of the DBD atomizer was passivated by dimethyldichlorosilane (DMDCS) resulting in a twofold increase of sensitivity. Sensitivity of 0.10 s ng-1 Pb and a limit of detection of 0.82 ng cm-3 Pb were reached in the DBD atomizer with DMDCS-modified surface under the optimum atomization conditions. Better performance was achieved in a QTA atomizer, in which detection limit of 0.59 ng cm-3 Pb was reached and sensitivity was doubled (0.22 s ng-1 Pb) in comparison with DMDCS- modified DBD.
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Selenium determination by HG-AAS with preconcentration and atomization in a dielectric barrier plasma discharge
Duben, Ondřej ; Kratzer, Jan (advisor) ; Rychlovský, Petr (referee)
The aim of this thesis was to optimize atomization conditions for selenium hydride in a novel plasma atomizer based on dielectric barrier discharge (DBD) using atomic absorption spectrometry as a detector. Analytical characteristics have been subsequently determined and compared to those reached in a conventional externally heated quartz tube atomizer which was replaced by a sofisticated design of a multiatomizer (MMQTA) in this work. The limit of detection reached in DBD (0,24 ng ml−1 Se) is slightly worse to that observed in MMQTA (0,15 ng ml−1 Se). On the contrary, slightly better resistance towards interferences of Sb, Bi and As was observed in DBD atomizer in comparison with MMQTA. Possibility of selenium preconcentration in a DBD atomizer was studied reaching an overall preconcentration efficiency of 75 ± 5%. The detection limit in a preconcentration mode employing preconcentration period of 300 s has reached 0,012 ng ml−1 Se. Key words: hydride generation atomic absorption spectrometry, dielectric barrier discharge, hydride atomization, hydride trapping, selenium
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A novel AAS atomizer based on a dielectric barrier plasma discharge
Novák, Petr ; Kratzer, Jan (advisor) ; Kanický, Viktor (referee)
Atomization of arsine in a novel hydride atomizer for atomic absorption spectrometry (HG-AAS) was thoroughly optimized. This plasma atomizer is based on a dielectric barrier discharge (DBD). Sensitivity and detection limit reached 0.48 s ng-1 As and 0.16 ng ml-1 As, respectively, under optimum atomization conditions (Ar discharge using a flow rate of 60 ml min-1 Ar, DBD power 17 W). Analytical figures of merit reached in DBD are comparable to those found in an externally heated quartz tube multiatomizer (MMQTA) that was chosen as a model of conventional approach to hydride atomization in HG-AAS. An extent of interferences (Se, Sb, Bi) during As determination was investigated comparing both MMQTA and DBD atomizers. The later one was found to be more resistant towards interferences. A simple preconcentration of As in a DBD atomizer was reached after oxygen introduction into the Ar plasma in the DBD resulting in analyte retention in the atomizer followed by its volatilization once the oxygen flow is switched off. Preconcentration efficiency of 100 % was reached and detection limit improvement by a factor of ten was achieved (0.01 ng ml-1 As, preconcentration period 300 s).
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