Number of found documents: 515
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Monitoring of enzymatic enantioselective acetylation of gem-difluorinated alcohols by capillary electrophoresis
Šolínová, Veronika; Pomeisl, Karel; Lamatová, Nikola; Pohl, Radek; Brabcová, Jana; Krečmerová, Marcela; Kašička, Václav
2018 - English
A new fast and highly efficient capillary electrophoretic (CE) method has been developed for chiral analysis of non-charged gem-difluorinated alcohol (3-(benzyloxy)-1,1-difluoro-propan-2-ol) using sulfobutylether-β-CD as chiral selector. The method was applied for monitoring of enzymatic (lipase mediated) enantioselective acetylation of the above alcohol and for determination of enantiomeric purity of both substrates and products of the enzymatic reaction. Keywords: enantioselective acetylation; difluorinated alcohols; capillary electrophoresis Available at various institutes of the ASCR
Monitoring of enzymatic enantioselective acetylation of gem-difluorinated alcohols by capillary electrophoresis

A new fast and highly efficient capillary electrophoretic (CE) method has been developed for chiral analysis of non-charged gem-difluorinated alcohol (3-(benzyloxy)-1,1-difluoro-propan-2-ol) using ...

Šolínová, Veronika; Pomeisl, Karel; Lamatová, Nikola; Pohl, Radek; Brabcová, Jana; Krečmerová, Marcela; Kašička, Václav
Ústav organické chemie a biochemie, 2018

Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis
Pangavhane, Sachin; Böhm, S.; Makrlík, E.; Ruzza, P.; Kašička, Václav
2018 - English
Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), cycl[-Val(1)-Pro(2)-Pro(3)-Ala(4)-Phe(5)-Phe(6)-Pro(7)-Pro(8)-Phe(9)-Phe(10)-], and sodium and potassium cations in methanol. Apparent stability constants of AA complexes with these alkali metal ions were determined from the dependence of effective mobility of AA on the concentration of these ions in the background electrolyte by the non-linear regression analysis. The AA complexes with Na+ and K+ ions were found to be relatively weak, with the apparent stability constants 343 L/mol and 35 L/mol, respectively. Keywords: affinity capillary electrophoresis; antamanide; binding constant Available at various institutes of the ASCR
Determination of stability constants of antamanide complexes with sodium and potassium ions by affinity capillary electrophoresis

Affinity capillary electrophoresis (ACE) was applied for quantitative investigation of the interactions between important biomolecule, cyclic decapeptide antamanide (AA), ...

Pangavhane, Sachin; Böhm, S.; Makrlík, E.; Ruzza, P.; Kašička, Václav
Ústav organické chemie a biochemie, 2018

Separation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis
Štěpánová, Sille; Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin; Kašička, Václav
2018 - English
A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some rotamers was obtained in sodium borate, pH 9.3, or in Tris-phosphate, pH 2.2, background electrolytes (BGEs) free of cyclodextrins (CDs). However, the best, baseline separations of the rotamers of 5-nitrosopyrimidines were achieved in sodium borate BGE, pH 9.3, containing 20 mg/mL beta-CD as stereoselector, or in Tris-phosphate BGE, pH 2.2, with carboxymethyl-beta-CD as stereoselector. Keywords: rotamers; 5-nitrosopyrimidines; capillary electrophoresis Available at various institutes of the ASCR
Separation of rotamers of 5-nitrosopyrimidines by capillary electrophoresis

A new capillary electrophoresis (CE) method was developed for the separation of a new type of stereoisomers - rotamers of polysubstituted 5-nitrosopyrimidine derivatives. Partial separation of some ...

Štěpánová, Sille; Procházková, Eliška; Čechová, Lucie; Žurek, Jiří; Janeba, Zlatko; Dračínský, Martin; Kašička, Václav
Ústav organické chemie a biochemie, 2018

Affinity capillary electrophoresis applied to chiral separations of diquats and to determination of the stability constants of their complexes with sulfated cyclodextrins
Kašička, Václav; Bílek, Jan; Koval, Dušan; Sázelová, Petra; Talele, Harish Ramesh; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Teplý, Filip
2018 - English
Affinity capillary electrophoresis (ACE) using an aqueous 22/35 mM sodium/phosphate buffer, pH 2.5, as the background electrolyte (BGE), and 6 mM randomly highly sulfated alpha-, beta- and gamma-cyclodextrins (CDs) as chiral selectors has been successfully applied for separation of (P)- and (M)-enantiomers of a series of eleven new diquats (DQs) and for estimation of the strength of their complexes with the above CDs. The apparent stability constants of the DQs-CDs complexes were determined from the simultaneous ACE measurements of the dependence of effective electrophoretic mobilities of (P)- and (M)-enantiomers of DQs on the concentrations of CDs in the BGE by nonlinear regression analysis. The DQs enantiomers formed strong complexes with all three types of CDs with the apparent stability constants in the range (7.80 547.4) × 103 L/mol. Keywords: affinity capillary electrophoresis; chiral separations; diquats Available at various institutes of the ASCR
Affinity capillary electrophoresis applied to chiral separations of diquats and to determination of the stability constants of their complexes with sulfated cyclodextrins

Affinity capillary electrophoresis (ACE) using an aqueous 22/35 mM sodium/phosphate buffer, pH 2.5, as the background electrolyte (BGE), and 6 mM randomly highly sulfated alpha-, beta- and ...

Kašička, Václav; Bílek, Jan; Koval, Dušan; Sázelová, Petra; Talele, Harish Ramesh; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Teplý, Filip
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

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

Vliv fungicidu thiramu na obsah chlorofylu a růst jahody zahradní (Fragaria Annanassa)
Jakl, M.; Jaklová Dytrtová, Jana; Navrátil, Tomáš; Marková, A.
2017 - Czech
Thiram je poměrně často používaný fungicid v zemědělství i zahradnictví. Jeho chování v systémech životního prostředí však nebylo dosud podrobně objasněno. V příspěvku byl zkoumán účinek přítomnosti thiramu ve třech různých typech půd a jeho vliv na obsah biomasy a chlorofylu v nádobovém pokusu s jahodami zahradními. Je možné konstatovat, že přítomnost thiramu v půdě významně zvýšila obsah chlorofylu a i b v mírně kyselé půdě z místa Humpolec. Změny zkoumaných parametrů lze připsat podpořené mobilizaci Mg, působící společně s dalšími živinami mobilizovanými při nízkém pH půdy. Obsah biomasy byl však přítomností thiramu v půdě snížen. 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. Keywords: pesticides; fungicides; magnesium; thiram Available at various institutes of the ASCR
Vliv fungicidu thiramu na obsah chlorofylu a růst jahody zahradní (Fragaria Annanassa)

Thiram je poměrně často používaný fungicid v zemědělství i zahradnictví. Jeho chování v systémech životního prostředí však nebylo dosud podrobně objasněno. V příspěvku byl zkoumán účinek přítomnosti ...

Jakl, M.; Jaklová Dytrtová, Jana; Navrátil, Tomáš; Marková, A.
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

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