Number of found documents: 545
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Iontové zdroje pro LC/MS
Cvačka, Josef
2018 - Czech
Byly popsány iontové zdroje, které se používají pro spojení kapalinového chromatografu s hmotnostním spektrometrem. The ion sources used for conection of liquid chromatograph and the mass spectrometer were described. Keywords: mass spectrometry; ionization Available at various institutes of the ASCR
Iontové zdroje pro LC/MS

Byly popsány iontové zdroje, které se používají pro spojení kapalinového chromatografu s hmotnostním spektrometrem....

Cvačka, Josef
Ústav organické chemie a biochemie, 2018

Determination of Bitrex in conifer needles using capillary electrophoresis
Jaklová Dytrtová, Jana; Jakl, M.; Konášová, Renáta; Kašička, Václav
2018 - English
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 %. Keywords: denatonium benzoate; needle extracts; capillary electrophoresis Available at various institutes of the ASCR
Determination of Bitrex in conifer needles using capillary electrophoresis

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 ...

Jaklová Dytrtová, Jana; Jakl, M.; Konášová, Renáta; Kašička, Václav
Ústav organické chemie a biochemie, 2018

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 ...

Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Teplý, Filip; Kašička, Václav
Ústav organické chemie a biochemie, 2018

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 ...

Jakl, M.; Jaklová Dytrtová, Jana
Ústav organické chemie a biochemie, 2018

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 ...

Šolínová, Veronika; Žáková, Lenka; Jiráček, Jiří; Kašička, Václav
Ústav organické chemie a biochemie, 2018

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 ...

Vrkoslav, Vladimír; Rumlová, Barbora; Cvačka, Josef
Ústav organické chemie a biochemie, 2018

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 ...

Strmeň, Timotej; Vrkoslav, Vladimír; Pačes, Ondřej; Cvačka, Josef
Ústav organické chemie a biochemie, 2017

Derivatizace v hmotnostní spektrometrii pro určování struktury
Cvačka, Josef
2017 - Czech
Přehled hmotnostně-spektrometrických přístupů pro určování poloh dvojných vazeb a methylových větvení u alifatických řetězců. An overview of mass spectrometric approaches for determining the positions of double bonds and methyl branches in aliphatic chains. Keywords: mass spectrometry; derivatization Available at various institutes of the ASCR
Derivatizace v hmotnostní spektrometrii pro určování struktury

Přehled hmotnostně-spektrometrických přístupů pro určování poloh dvojných vazeb a methylových větvení u alifatických řetězců....

Cvačka, Josef
Ústav organické chemie a biochemie, 2017

ICP-OES s elektrotermickou vaporizací (ETV) a příklady využití metody při přímé analýze různých biologických materiálů
Matějková, Stanislava
2017 - Czech
Optická spektrometrie s indukčně vázaným plasmatem a elektrotermickou vaporizací (ETV-ICP-OES) je metodou umožňující jednoduché a rychlé přímé stanovení makro-, mikro- i stopových prvků v pevných i kapalných vzorcích bez předchozí úpravy. Metoda snižuje riziko kontaminace vzorků a vzhledem k vysoké efektivitě přenosu analytů do plasmatu je možno provádět analýzu z velmi malého množství vzorků (jednotky mg). V naší laboratoři byla vyvinuta metoda pro sledování hladiny a chování derivátů karboranů v organismu na základě stanovení koncentrace boru a kobaltu v malých množstvích myších tkání (5 – 10 mg séra, jater mebo mozku). Dále byly vyvinuty metody pro rychlou simultánní analýzu makro- i mikroelementů v rostlinném materiálu a stanovení potenciálně škodlivých prvků v tělech pískomilného hmyzu. Solid sampling electrothermal vaporization (ETV) inductively coupled plasma optical emission spectroscopy (ICP-OES) enable simple and rapid multielemental analysis of major, minor and trace elements without the need for pre-treatment of solid or liquid samples. By comparison with more common ICP-OES combined with a solution nebulization, the risk of contamination of analysed samples is reduced. The detection limits and the sample quantity needed for analysis via ETV-ICP-OES decrease as a result of the high-efectivity transport of the sample aerosol into the ICP torch. The connection of ETV unit to simultaneous ICP-OES allows us the fast direct and fully automatised analysis of numerous samples. The technique enable usually the combined calibration with home-made or certified solid and aqueous standards. We developed the methodology for tracking the carboran-based candidate-drugs time dependent concentration and for their pharmacokinetic evaluation. The method is based on direct boron or together boron and cobalt contents direct estimation in little amounts of fresh frozen mice tissues (5 – 10 mg of serum, brain or liver). We created also methods for multielement analysis of plant material and for determination of potentionaly harmful elements in insect bodies.\n Keywords: ETV-ICP-OES; biological samples; multielemental analysis Available at various institutes of the ASCR
ICP-OES s elektrotermickou vaporizací (ETV) a příklady využití metody při přímé analýze různých biologických materiálů

Optická spektrometrie s indukčně vázaným plasmatem a elektrotermickou vaporizací (ETV-ICP-OES) je metodou umožňující jednoduché a rychlé přímé stanovení makro-, mikro- i stopových prvků v pevných i ...

Matějková, Stanislava
Ústav organické chemie a biochemie, 2017

Od běžných ke speciálním aplikacím zobrazovací hmotnostní spektrometrie
Vrkoslav, Vladimír
2017 - Czech
Bylo popsáno využití desorpčních ionizačních technik pro zobrazování distribuce molekul v typických i nestandardních aplikacích. The use of desorption ionization techniques for the distribution of molecules in both typical and non-standard applications was described. Keywords: MSI; molecular imaging Available at various institutes of the ASCR
Od běžných ke speciálním aplikacím zobrazovací hmotnostní spektrometrie

Bylo popsáno využití desorpčních ionizačních technik pro zobrazování distribuce molekul v typických i nestandardních aplikacích....

Vrkoslav, Vladimír
Ústav organické chemie a biochemie, 2017

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