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Estimation of binding constants of associates of Ru(II) and Fe(II) polypyridyl complexes with single-isomer sulfated cyclodextrins by capillary electrophoresis
Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Teplý, Filip; Kašička, Václav
2018 - English
Capillary electrophoresis (CE) was applied for enantioseparations of [Ru(bpy)3]2+, [Ru(phen) 3]2+ and [Fe(phen) 3]2+ complexes and for the estimation of binding constants of their associates with selected single-isomer sulfated cyclodextrins (SCDs). The apparent binding constants of the complexes of [Ru(bpy)3]2+, [Ru(phen)3]2+, and [Fe(phen)3]2+ enantiomers with the above SCDs were determined from the dependence of their effective electrophoretic mobilities on the concentration of the SCDs in the background electrolyte. Calculated apparent binding constants were found to be smaller than those obtained for randomly sulfated SCDs.
Keywords:
polypyridyl complexes; stability constant; capillary electrophoresis
Available at various institutes of the ASCR
Estimation of binding constants of associates of Ru(II) and Fe(II) polypyridyl complexes with single-isomer sulfated cyclodextrins by capillary electrophoresis
Capillary electrophoresis (CE) was applied for enantioseparations of [Ru(bpy)3]2+, [Ru(phen) 3]2+ and [Fe(phen) 3]2+ complexes and for the estimation of binding constants of their associates with ...
Penconazole and its behaviour in the presence of copper
Jakl, M.; Jaklová Dytrtová, Jana
2018 - English
Penconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its interactions e.g. with copper, typically present in soil as an ion (or in week complexes) or in bodies, as a part of enzymes. This study brings the information potentially useful in the evaluation of penconazole fate in the environment. The studies based on the electrospray gas phase experiments provide an estimate of the penconazole reactivity in copper presence including its possible degradation pathways.
Keywords:
triazoles; Cu(II); Cu(I); mass spectrometry; ESI-MS; stability; degradation
Available at various institutes of the ASCR
Penconazole and its behaviour in the presence of copper
Penconazole is a fungicide frequently used in agriculture. Its possible impact to (non-)target species is influenced by its interactions e.g. with copper, typically present in soil as an ion (or in ...
Determination of binding constants of human insulin complexes with serotonin, dopamine, arginine, and phenol by pressure assisted partial filling affinity capillary electrophoresis
Šolínová, Veronika; Žáková, Lenka; Jiráček, Jiří; Kašička, Václav
2018 - English
A new method, pressure assisted partial filling affinity capillary electrophoresis (PF-ACE), has been developed to study noncovalent interactions of the hexamer of human insulin (HI) with cationic ligands, such as phenolic neurotransmitters serotonin and dopamine, and amino acid arginine, or with anionic ligand phenol, in alkaline aqueous solutions. The apparent binding constants, Kb, of the HI-ligand complexes were determined from the dependence of the effective migration time changes of the above ligands on the variable zone lengths of HI dissolved in the background electrolyte and hydrodynamically introduced into the bare fused silica capillary close to the UV detector. The HI interactions with the above ligands were found to be moderately strong, with Kb values in the range 385-1314 L/mol.
Keywords:
human insulin; ligand; affinity capillary electrophoresis
Fulltext is available at external website.
Determination of binding constants of human insulin complexes with serotonin, dopamine, arginine, and phenol by pressure assisted partial filling affinity capillary electrophoresis
A new method, pressure assisted partial filling affinity capillary electrophoresis (PF-ACE), has been developed to study noncovalent interactions of the hexamer of human insulin (HI) with cationic ...
Temperature-programed micro-HPLC analysis of fatty acid methyl esters with APCI-MS detection
Vrkoslav, Vladimír; Rumlová, Barbora; Cvačka, Josef
2018 - English
HPLC/APCI-MS analysis at microliters-per-minute flow rates was optimized for separation of fatty acid methyl esters (FAMEs). HPLC C18 column with an internal diameter of 0.3 mm and isocratic elution using 99.9 % acetonitrile and 0.1% formic acid were employed. Standard APCI ion source was suitable for detection of FAMEs at 10 μl/min flow rate with the detection limit of micrograms-per-milliliter. APCI-MS spectra with predominant [M + H]+ molecular adducts were observed. The main advantage of micro-flow measurements is the possibility of using a temperature gradient, which significantly reduces retention times of FAMEs with longer aliphatic chain. The significant reduction of solvent consumption is also an important economic and environmental advantage. The positions of double bonds in FAME chains were established using acetonitrile-related adducts and tandem mass spectrometry. The optimized method was applied for analysis of FAMEs in triacylglycerol fraction of black currant seeds oil.
Keywords:
liquid chromatography; mass spectrometry; atmospheric pressure chemical ionization
Fulltext is available at external website.
Temperature-programed micro-HPLC analysis of fatty acid methyl esters with APCI-MS detection
HPLC/APCI-MS analysis at microliters-per-minute flow rates was optimized for separation of fatty acid methyl esters (FAMEs). HPLC C18 column with an internal diameter of 0.3 mm and isocratic elution ...
Development of a tube nebulizer for microflow atmospheric pressure chemical ionization mass spectrometry
Strmeň, Timotej; Vrkoslav, Vladimír; Pačes, Ondřej; Cvačka, Josef
2017 - English
A novel nebulizer for microflow atmospheric pressure chemical ionization mass spectrometry was developed. It consisted of a tube with analyte-transporting fused silica capillary inside. The terminal part of the tube was resistively heated using a coiled resistance wire. Optimal nebulizer parameters and construction setup were investigated to fully demonstrate its versability. Corundum appeared to be a more suitable material than quartz for fabrication of the tube nebulizer. The lowest analyte flow rate investigated was 1.0 mul/min with an excellent signal stability reached.
Keywords:
mass spectrometry; micro-APCI; tube nebulizer
Available at various institutes of the ASCR
Development of a tube nebulizer for microflow atmospheric pressure chemical ionization mass spectrometry
A novel nebulizer for microflow atmospheric pressure chemical ionization mass spectrometry was developed. It consisted of a tube with analyte-transporting fused silica capillary inside. The terminal ...
Charge Transport through Molecular Towers Based on Tetraphenylmethane Tripods
Kolivoška, V.; Šebera, Jakub; Lindner, M.; Valášek, M.; Mayor, M.; Mészáros, G.; Gasior, J.; Hromadová, M.
2017 - English
Molecular platforms with multiple anchors were introduced recently to provide robust coupling between molecular electronic components and metallic electrodes. In this work, charge transport in tower-shaped single molecule conductors based on tetraphenylmethane tripod possessing three thiol anchors is investigated by scanning tunneling microscopy break junction technique. The effect of tripod substitution pattern and number of repeating units in molecule is addressed. The substitution was found to influence conductance value in early stages of molecular junction evolution, where tower lays parallel to surface. In late stages, the charge is transported through principal molecular axis and junction breaks thermally in tilted configuration.
Keywords:
charge transport through single molecules; break junction technique; molecular electronics
Available at various institutes of the ASCR
Charge Transport through Molecular Towers Based on Tetraphenylmethane Tripods
Molecular platforms with multiple anchors were introduced recently to provide robust coupling between molecular electronic components and metallic electrodes. In this work, charge transport in ...
Capillary isotachophoresis and zone electrophoresis applied to determination of effective charge of polyelectrolytes
Kašička, Václav; Koval, Dušan; Ibrahim, A.; Chamieh, J.; Cottet, H.
2016 - English
Capillary electromigration methods, isotachophoresis (CITP) and zone electrophoresis (CZE) were applied to determination of effective charge of poly-alpha-L-glutamic acid and poly-alpha-L-lysine using both CITP-dedicated device and common CZE apparatus. Combination of CITP and CZE methods in both these types of devices proved to be a suitable platform for determination of effective charge of a wide range of polyelectrolytes – weak and strong, polycations and polyanions.
Keywords:
capillary isotachophoresis; polyelectrolytes; effective charge
Available at various institutes of the ASCR
Capillary isotachophoresis and zone electrophoresis applied to determination of effective charge of polyelectrolytes
Capillary electromigration methods, isotachophoresis (CITP) and zone electrophoresis (CZE) were applied to determination of effective charge of poly-alpha-L-glutamic acid and poly-alpha-L-lysine using ...
Determination of stability constants of [Gly6]-antamanide complexes with small cations by affinity capillary electrophoresis
Pangavhane, Sachin; Makrlík, E.; Ruzza, P.; Kašička, Václav
2016 - English
Affinity capillary electrophoresis (ACE) was employed for the determination of apparent stability constants Kst of complexes of cyclic peptide [Gly6]-antamanide ([Gly6]-AA) with alkali and alkali-earth metal ions: Li+, Na+, K+, Rb+, Cs+, NH4+, and Ca2+. Kst was determined from the dependence of effective mobility of [Gly6]-AA on the concentration of these ions in the background electrolyte using the non-linear regression analysis. Kst were found to be in the range 13.3 – 26.3.
Keywords:
affinity capillary electrophoresis; [Gly6]-antamanide; stability constant
Available at various institutes of the ASCR
Determination of stability constants of [Gly6]-antamanide complexes with small cations by affinity capillary electrophoresis
Affinity capillary electrophoresis (ACE) was employed for the determination of apparent stability constants Kst of complexes of cyclic peptide [Gly6]-antamanide ([Gly6]-AA) with alkali and ...
Investigation of acid-based properties of mono- and diaza[5]helicenes by non-aqueous capillary electrophoresis and quantum chemical calculations
Šolínová, Veronika; Štěpánová, Sille; Jančařík, Andrej; Klívar, Jiří; Šámal, Michal; Stará, Irena G.; Vacek Chocholoušová, Jana; Vacek, Jaroslav; Starý, Ivo; Kašička, Václav
2016 - English
Non-aqueous capillary electrophoresis (NACE) using methanol (MeOH) as a solvent of the background electrolytes was used to determine the thermodynamic acidity (ionization) constants (pKa) of a series of monoaza[5]helicenes and diaza[5]helicenes protonated to the first degree in MeOH and water. Depending on the number and position of the nitrogen atoms in their molecules, the analyzed aza[5]helicenes were found to be weak to moderate bases with methanolic pKa,MeOH in the range 3.90-8.75 and with aqueous pKa,H2O in the range 3.53-8.28.
Keywords:
capillary electrophoresis; azahelicenes; acidity constant
Available at various institutes of the ASCR
Investigation of acid-based properties of mono- and diaza[5]helicenes by non-aqueous capillary electrophoresis and quantum chemical calculations
Non-aqueous capillary electrophoresis (NACE) using methanol (MeOH) as a solvent of the background electrolytes was used to determine the thermodynamic acidity (ionization) constants (pKa) of a series ...
Capillary electrophoretic separation and structure-mobility relationship study of cyclic antimicrobial peptides
Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav
2016 - English
Capillary electrophoresis (CE) has been employed for qualitative and quantitative analysis, separation and physicochemical characterization of antimicrobial peptides isolated from the venom of eusocial bee Lassioglossum laticeps. From the CE experiments at various pH, the important physico-chemical parameters of analyzed peptides, effective mobilities and acidity constants were determined and the structure-mobility relationships of peptides with variable intramolecular cyclization of their molecules were investigated.
Keywords:
antimicrobial peptides; capillary electrophoresis; structure-mobility relationships
Available at various institutes of the ASCR
Capillary electrophoretic separation and structure-mobility relationship study of cyclic antimicrobial peptides
Capillary electrophoresis (CE) has been employed for qualitative and quantitative analysis, separation and physicochemical characterization of antimicrobial peptides isolated from the venom of ...
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