|
|
Determination of Bitrex in conifer needles using capillary electrophoresis
Jaklová Dytrtová, Jana ; Jakl, M. ; Konášová, Renáta ; Kašička, Václav
Two extraction procedures have been developed for the sample preparation regarding the determination of Bitrex (Denatonium benzoate) on the surface of conifer needles (1) and in the biomass of the chopped conifer needles (2). The content of the Bitrex in the extracts was determined by capillary electrophoresis with UV-absorption photometric detection. The recovery of Bitrex from the needle surface is 90%, however the procedure designed for determination of Bitrex from needles is not sufficient, because the recovery is only 30 %.
|
|
|
Investigation of copper complexes using mass spectrometry
Yassaghi, Ghazaleh ; Roithová, Jana (advisor) ; Jaklová Dytrtová, Jana (referee) ; Polášek, Miroslav (referee)
This dissertation thesis reports the study of several copper complexes and their reactivity in the gas phase. The complexes were analyzed using different methods, namely, electrospray ionization-mass spectrometry (ESI-MS), infrared multiphoton dissociation (IRMPD) spectroscopy and theoretical calculations. In the first part, the complexes of redox-active ligands (catechol, maltol, and phenanthraquinone) with copper were studied under electrospray ionization conditions. [Cu(PQ)2]+ (PQ = 9,10-phenanthraquinone), [Cu(maltol)(maltol-H)]+ and [Cu(maltol)(maltol-H2)]+ were produced by electrospray ionization. The copper complexes were compared with complexes of other metals (Zn, Ag, and Na), and the structures were studied by collision induced dissociation (CID) and IRMPD spectroscopy. The redox process of copper complexes was studied using the C-O stretching mode as a redox marker and using fragmentation experiments. Both the phenanthraquinone and maltol ligands showed redox activity of the studied copper complexes in the gas phase. In the second part, negatively charged complexes of copper with pincer ligand L (L = N,N'-bis[2,6-diisopropylphenyl]-2,6-pyridinedicarboxamide) were investigated to show the effects of different counter-ions. The results showed that electrospray ionization of copper chlorate...
|
|
|
Influence of Fungicide Thiram on Chlorophyll Content and on the Growth of Garden Strawberry (Fragaria Annanasa)
Jakl, M. ; Jaklová Dytrtová, Jana ; Navrátil, Tomáš ; Marková, A.
Thiram is a relatively frequently used fungicide in agriculture and gardening. However, its behavior in environmental systems has not been elucidated in detail up to now. The effect of thiram presence in three different soil types on the yield and chlorophyll contents in garden strawberry plantation was investigated. It is possible to conclude that its presence in soil significantly increased the chlorophyll a and b contents in slightly acidic soil from Humpolec location. The changes of investigated parameters could be ascribed to supported mobilization of Mg, acting together with other nutrients mobilized in low pH of soils. The yield decreased addition in all tested soil types under thiram application.
|
|
| |
|
|
Use of capillary electrophoresis with UV photometric and electrospray ionization mass spectrometric detection for the study of interaction of compounds
Konášová, Renáta ; Jaklová Dytrtová, Jana (advisor) ; Mikšík, Ivan (referee) ; Tůma, Petr (referee)
Capillary electrophoresis (CE) is highly efficient separation method based on the different migration velocity of ions in liquid media in electric field. It is commonly used in analytical laboratories and due to the different separation principle it is applied as a complementary method to the chromatographic methods (HPLC and UHPLC). Beside the applicability of CE for quantitative/qualitative analysis, the method can be used also for physico-chemical characterization of compounds (e.g. determination of acid dissociation constants of weak electrolytes or stability constants of complexes). This work is focused on the applicability of CE methods for determination of physico- chemical characteristic of compounds (acid dissociation constants of triazole fungicides and stability constants of dibenzo-18-crown-6, benzo-18-crown-6 and 18-crown-6 ether complexes with metal ions in hydro-organic solvent mixtures) and on the possibility to use affinity CE (ACE) with electrospray ionization-mass spectrometric detection (ACE- ESI/MS) for the study of non-covalent interactions of compounds. For the online hyphenation of CE and ESI/MS, two highly sensitive CE-ESI/MS interfaces were tested: i) porous tip and ii) nano-sheath liquid flow. The ability of the CE-ESI/MS interfaces to effectively decouple spray and...
|
|
|
Study of tebuconazole complexes with metal ionts
Norková, Renáta ; Jaklová Dytrtová, Jana (advisor) ; Vyskočil, Vlastimil (referee)
Tebuconazole belongs to widely utilized plant fungicides, mostly in vineyards. Its traces are present in plant tissues, wine as well as in soil. The aim of the study was to determine stoichiometries and stabilities of metal (Cu, Zn, Cd, Ca and Ag) complexes with tebuconazole (1) by means of electrospray ionization mass spectrommetry (ESI-MS). It was found that the complexes of tebuconazole with copper ions are particularly stable ([Cu(1)]+ has appearance energy 224 kJ·mol-1 , corresponding with the dissociation of the water molecule from the tebuconazole molecule), while the stability of another tebuconazole complexes is lower, about 150 kJ·mol-1 . In real environmental samples, the detection of 1 itself is hampered by its spreading into various species. The method involved here is based upon a hyphenation of electrochemistry (amperometry) and electrospray-ionization mass spectrometry (ESI-MS). It uses the fact that Cu creates very stable complexes with 1. We demonstrate that at appropriate potentials (at higher than 500 mV) Cu cations can be generated in an electrochemical cell and subsequently form complexes with 1 present in the sample. The resulting complex [Cu(1)]+ is detected with ESI-MS. The intensity of detected complexes depends on the concentration of 1 and the oxidation level of the...
|
|
|
Study of C-C coupling of dienes catalyzed by ruthenium(II) complexes
Hanikýřová, Eva ; Roithová, Jana (advisor) ; Jaklová Dytrtová, Jana (referee)
Title: Study of C-C coupling of dienes catalyzed by ruthenium (II) complexes. Author: Bc. Eva Hanikýřová Department: Department of Organic Chemistry Supervisor: Mgr. Jana Roithová, Ph.D. Abstract Transition metal catalyzed cycloadditions have contributed extensively to organic synthesis. The use of ruthenium complexes in those reactions gain importance due to their demonstrated ability in the catalytic carbon-carbon bond formations via ruthenacycle intermediates. In our studies, we have concentrated on the interaction between ruthenium (II) and alkenes using mass spectrometry with electrospray ionization. This technique allows to investigate ruthenium complexes in the ionized states, and allows to investigate these structures by using MS/MS analyse. Our experimental research was complemented by quantum chemical calculations using Density functional theory. The research leads to a more detailed understanding to Ruthenium complexes with unsaturated hydrocarbons reaction mechanism. Key words Gas-phase chemistry, Reaction mechanisms, Electrospray Ionization, Catalyst, [CpRu(CH3CN)3]PF6, Mass Spectrometry
|
|
| |
|
| |
|
| |
guest ::
