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Thick-film amperometric sensor array
Růžička, Tomáš ; Prášek, Jan (referee) ; Adámek, Martin (advisor)
Supposed work deals with proposal and construction of thick-film amperometric sensor array. The reason of this proposal of sensor array is multiple increase of speed, increase of accuracy and enlargement of possibilities of measuring against current optical system. In theoretic part there is described method of seriography and electrochemical analytic method for determination of chemical elements in the solution. Practical part is composed of proposal of topology of electrochemical sensor electrodes, their comparison according to characteristics and subsequently of the proposal of sensor array. For testing of function of sensor array measuring by method of cyclical voltametry was done with the help of default electrochemical oxidative-reducing pair of potassium ferro-ferricyanide.
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Optimization of the operational temperature of photoluminescence sensor field for detection of linear alcohols
Pokorný, Matěj ; Dian, Juraj (advisor) ; Červený, Václav (referee)
Chemical sensors are used to detect the presence of chemical substances using various physical quantities. Porous silicon, prepared by electrochemically etching the surface of crystalline silicon with a mixture of hydrofluoric acid and ethanol under appropriate conditions, is a porous material that contains nanocrystalline forms of silicon. Nanocrystalline silicon exhibits intense photoluminescence properties at room temperature, which strongly depend on the presence of chemical substances in its surroundings. The photoluminescence intensity of porous silicon is generally quenched in the presence of the analyte. The photoluminescence sensor response to the substances to be determined depends mainly on the concentration of the substance in question, but also on the operating conditions. Most critical is the operating temperature, which fundamentally affects the intensity of photoluminescence and the rate of sensor response when the analyte is added or removed from the system. The aim of this bachelor thesis was the preparation of porous silicon samples and their characterization by infrared (FTIR) and photoluminescence spectroscopy. These samples were tested as sensor elements of a photoluminescence sensor array for the detection of ethanol linear alcohol vapor. The main objective of the bachelor...
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Photoluminescence sensor field applied for detection of chemical compounds in gas mixtures
Liška, Jiří ; Dian, Juraj (advisor) ; Broncová, Gabriela (referee)
Title: Photoluminescence sensor field applied for detection of chemical compounds in gas mixtures Author: Jiří Liška Department: Department of Analytical Chemistry Supervisor: doc. RNDr. Juraj Dian, CSc. Abstract Porous silicon is a nanostructured material that can be prepared by galvanic etching of silicon in the presence of hydrofluoric acid. The properties of this material can be influenced by way of preparation or by the chemical modification of the surface. Porous silicon has many extraordinary properties as compared to macrocrystalline silicon; the most important one for chemical sensing is the visible photoluminescence at room temperature. In the presence of organic and inorganic analytes in the gas phase, the photoluminescence of the material is quenched. This phenomenon can be used for chemical sensors of chemical compounds in the gas phase. These sensors are very sensitive and give reasonable results for organic compounds. Photoluminescence sensor field uses for measurement several sensor elements with the modified surface. It is possible to use this method for the identification and determination of gaseous organic compounds. The aim of this thesis was: 1. the preparation of porous silicon samples, 2. the modification of surface with different methods, 3. the characterization of samples with FTIR...
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Thick-film amperometric sensor array
Růžička, Tomáš ; Prášek, Jan (referee) ; Adámek, Martin (advisor)
Supposed work deals with proposal and construction of thick-film amperometric sensor array. The reason of this proposal of sensor array is multiple increase of speed, increase of accuracy and enlargement of possibilities of measuring against current optical system. In theoretic part there is described method of seriography and electrochemical analytic method for determination of chemical elements in the solution. Practical part is composed of proposal of topology of electrochemical sensor electrodes, their comparison according to characteristics and subsequently of the proposal of sensor array. For testing of function of sensor array measuring by method of cyclical voltametry was done with the help of default electrochemical oxidative-reducing pair of potassium ferro-ferricyanide.
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Multichannel instrumentation for electrochemical measurement from sensor array
Žák, Jaromír ; Kizek, René (referee) ; Hubálek, Jaromír (advisor)
The work deals with n-channel system enabling many sample analysis at sort time from sensor array using electrochemical methods. The 8x12 sensor arrays are formed from 3 electrodes system created on PCB which can be used for heavy metal analysis and toxic substances determination. The control unit switches each 3 electrode sensor to 8 channel precise potentiostat which was designed for electrochemical analysis with current sensitivity below 10 pA. The potentiostat can synchronize with control unit. Developed system is able to measure up to eight single inputs and may be simply converted to measure other nonchemical values. Measured data will be sent to user-friendly application in computer and analyzed or saved consequently.
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