Number of found documents: 577
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Aldrithiol-2 as a new derivatization agent for double bond localization in unsaturated compounds by mass spectrometry
Strmeň, Timotej; Cvačka, Josef
2019 - English
A new method for localizing double bonds in lipids using derivatization with 2,2'-clipyridyl disulfide (Aldrithio-2) and electrospray ionization mass spectrometry (EST-MS) is presented. The derivatization introduces a permanent charge to the molecules. When collisionally activated, the derivatives provide diagnostic peaks useful for establishing the position of the original double bond. Since permanent charge of the derivative significantly increases the detectability of analytes, the method works well also for of very low polarity like hydrocarbons. Keywords: aldrithiol-2; double bond; electrospray; lipids; mass spectrometry Available at various institutes of the ASCR
Aldrithiol-2 as a new derivatization agent for double bond localization in unsaturated compounds by mass spectrometry

A new method for localizing double bonds in lipids using derivatization with 2,2'-clipyridyl disulfide (Aldrithio-2) and electrospray ionization mass spectrometry (EST-MS) is presented. The ...

Strmeň, Timotej; Cvačka, Josef
Ústav organické chemie a biochemie, 2019

Úvod do vysokorozlišující MS
Cvačka, Josef
2019 - Czech
Keywords: mass spectrometry Available at various institutes of the ASCR
Úvod do vysokorozlišující MS

Cvačka, Josef
Ústav organické chemie a biochemie, 2019

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

Ambient ionization techniques
Vrkoslav, Vladimír
2018 - Czech
In the first part of the lecture definition and classification of ambient ionization techniques were described. In the next part the principles of the most important ambient ionization techniques were explained and their use was mentioned. V první část přednášky se zabývá vymezením pojmu ambientních ionizačních technika a rozdělením těchto technik. V další části byly vysvětleny principy nejdůležitějších ambientních ionizačních technika a bylo popsáno jejich využití. Keywords: mass spectrometry Available at various institutes of the ASCR
Ambient ionization techniques

In the first part of the lecture definition and classification of ambient ionization techniques were described. In the next part the principles of the most important ambient ionization techniques were ...

Vrkoslav, Vladimír
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 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

Enantioseparation and estimation of racemization barriers of selected helquats and their derivatives by capillary electrophoresis using sulfated cyclodextrins as chiral selectors
Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Jirásek, Michael; Teplý, Filip; Kašička, Václav
2018 - English
Anionic highly sulfated β- and γ-cyclodextrins (S-CDs) and single-isomer heptakis-(2,3-diacetyl-6-sulfato)-β-CD (14Ac-7S-β-CD) were used for chiral separation of [5], [6] and [7]-ring helquats and helquat styryl dyes by capillary electrophoresis (CE) in the background electrolyte composed of 22 mM NaOH/35 mM H3PO4, pH 2.4. The CE method was applied for monitoring of racemization of eight helquats and helical dyes. Rate constant k of conversion, half-life T1/2 of racemization, and activation Gibbs free energy ΔGǂ of interconversion of one enantiomer into the other were calculated from the dependence of natural logarithm of enantiomeric excess (ee) on time using linear regression analysis. Keywords: helquats; racemization barrier; capillary electrophoresis Fulltext is available at external website.
Enantioseparation and estimation of racemization barriers of selected helquats and their derivatives by capillary electrophoresis using sulfated cyclodextrins as chiral selectors

Anionic highly sulfated β- and γ-cyclodextrins (S-CDs) and single-isomer heptakis-(2,3-diacetyl-6-sulfato)-β-CD (14Ac-7S-β-CD) were used for chiral separation of [5], [6] and [7]-ring helquats and ...

Sázelová, Petra; Koval, Dušan; Severa, Lukáš; Reyes Gutierrez, Paul Eduardo; Jirásek, Michael; Teplý, Filip; Kašička, Václav
Ústav organické chemie a biochemie, 2018

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

The ion sources used for conection of liquid chromatograph and the mass spectrometer were described.

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

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