|
|
Optimization of generation and atomization of arsines for speciation analysis by atomic fluorescence spectrometry
Marschner, Karel ; Dědina, Jiří (advisor) ; Komárek, Josef (referee)
Speciation analysis of arsenic based on selective hydride generation and detection by atomic fluorescence spectrometry have been studied in this work. It was found that under optimum conditions of atomization in the flame in gas shield atomizer, sensitivity was approximately twice higher and detection limit was about four times lower compared to miniature diffusion flame, which is a standard atomizer for atomic fluorescence spectrometry. The conditions to generate hydrides from both inorganic forms of the arsenic, i.e. from arsenite and arsenate, with the same efficiency have been found in the batch arrangement, by using 1 mol dm-3 hydrochlorid acid and 1% solution of tetrahydridoborate. To determine only trivalent form, TRIS buffer at pH 6.00 was used together with 1% sodium tetrahydridoborate. The detection limits found for inorganic arsenic, i.e. for arsenite and arsenate, respectively, were 15 ng dm-3 and 9 ng dm-3 . It was found that in the batch arrangement under these conditions it is possible to generate corresponding hydrides methylarsonate and dimethylarsonate with the same efficiency as from the inorganic form. Finally, it was found when slightly changing the gas-liquid separator design in order to introduce the mixture of tetrahydridoborate with hydrochloric acid to the bottom of the...
|
|
|
Construction of miniature flow-through cells for electrochemical generation of volatile compounds
Hraníček, Jakub ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
(EN) The presented dissertation thesis summarizes the new results of electrochemical generation of volatile compounds usable in atomic spectral methods. The main aim of this work is to develop and to characterize new types of electrolytic flow-through cells and to examine their possibilities of determination of arsenic, selenium and antimony by using the electrochemical hydride generation technique coupled with atomic absorption spectrometry with a quartz tube atomizer. Individual electrolytic cells were designed and constructed to comply with two important requirements. The cathode chamber of the electrolytic cell should have a minimal volume and a high efficiency of analyte conversion to the volatile hydride. Constructed electrolytic cells are divided into the construction groups and described in the experimental part. Selenium was chosen as the first analyte. The relevant working parameters (such as type, concentration and flow rate of electrolytes, generation current and carrier gas flow rate) were optimized for each newly constructed electrolytic cell. Under the optimal working parameters, the basic characteristics of selenium determination were found out by using electrochemical hydride generation. The electrolytic cells were compared to each other and with the classical electrolytic cell...
|
|
|
Novel Approaches to the Application of Electrochemical Volatile Compounds Generation in Spectrometric Methods
Červený, Václav ; Rychlovský, Petr (advisor) ; Spěváčková, Věra (referee) ; Komárek, Josef (referee)
Various possibilities for the use of electrochemical generation of volatile compounds for the determination of trace and ultratrace quantities of elements using atomic absorption spectrometry and optical emission spectrometry, respectively, were studied in this work. The Thesis is divided into four thematic sections. Electrochemical cold mercury vapor generation is common to the first two parts. The third part is devoted to electrochemical generation of the volatile form of cadmium and the last part deals with the use of the electrochemical hydride generator as a derivatization unit for speciation analysis of arsenic compounds. The optimization of each individual determination was carried out including, for example, various designs of the generator of volatile compounds (forms) of the analyte, the changes in the design of the gas-liquid separator, optimization of the concentration and the flow rate of all the solutions and the carrier gas. However, the value of the electric current employed was the most important parameter. In the first section, the in-situ trapping system of the cold mercury vapor generated in the graphite furnace (with the inner surface covered with a gold foil) of the atomic absorption spectrometer was also designed and optimized. The absolute limit of detection, 80 pg, was...
|
|
|
Preconcentration of Hydride Forming Elements in Quartz Atomizers for Atomic Absorption Spectrometry
Kratzer, Jan ; Dědina, Jiří (advisor) ; Komárek, Josef (referee) ; Spěváčková, Věra (referee)
CHARLES UNIVERSITY IN PRAGUE FACULTY OF SCIENCE Department of Analytical Chemistry PRECONCENTRATION OF HYDRIDE FORMING ELEMENTS IN QUARTZ ATOMIZERS FOR ATOMIC ABSORPTION SPECTROMETRY Synopsis of the PhD Thesis Prague 2008 RNDr. Jan Kratzer 2 CONTENTS CONTENTS................................................................................................................... 2 CURRICULUM VITAE............................................................................................... 4 LIST OF PUBLICATIONS ......................................................................................... 6 ABSTRACT................................................................................................................... 9 1 ULTRATRACE ANALYSIS OF HYDRIDE FORMING ELEMENTS ....... 11 2 OBJECTIVES OF THE THESIS ...................................................................... 13 3 EXPERIMENTAL .............................................................................................. 15 3.1 Apparatus ....................................................................................................... 15 3.2 Procedure........................................................................................................ 16 3.3 Detection by atomic absorption spectrometry...
|
|
|
Accuracy testing of minor horizontal geodetic control determined by analytical aerotriangulation
Komárek, Josef ; Weigel, Josef (referee) ; Kratochvíl, Radim (advisor)
The purpose of this bachelor’s thesis is testing quality of minor horizontal geodetic control points in chosen area in South Bohemia. The control points have been established in the eighties of twentieth century during cadastrial mapping (large scale base map). Until now, those points were recorded in the 4th accuracy class. The geodetic control was remeasured with RTK technique, then deviations were calculated. These results were reviewed and evaluated whether the points match with the 4th accuracy class or even the 3rd accuracy class. The results were submitted to the local cadastral office in Jindřichův Hradec.
|
|
| |
guest ::
RSS feed.