Number of found documents: 392
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Mobilization of neutral compounds by inorganic and small organic ions in capillary electrophoresis
Křížek, T.; Martínková, E.; Kubíčková, A.; Hladílková, Jana; Coufal, P.; Heyda, J.; Jungwirth, Pavel
2016 - English
The present study shows that neutral low-molecular-mass compounds that are presumed to possess zero electrophoretic mobility and are thus used as markers of electroosmotic flow in capillary electrophoresis can acquire electrophoretic mobility due to ion-specific interactions with constituents of background electrolyte. Therefore, these neutral markers, such as thiourea or dimethyl sulfoxide, can be separated in electric field and their migration order can vary depending on background electrolyte composition. This observation has some important implications for analytical and physico-chemical measurements using capillary electrophoresis because the choice of the marker-background electrolyte combination can influence the results of the measurement. Keywords: capillary electrophoresis; EOF markers; ion-specific effects; mobilization Available at various institutes of the ASCR
Mobilization of neutral compounds by inorganic and small organic ions in capillary electrophoresis

The present study shows that neutral low-molecular-mass compounds that are presumed to possess zero electrophoretic mobility and are thus used as markers of electroosmotic flow in capillary ...

Křížek, T.; Martínková, E.; Kubíčková, A.; Hladílková, Jana; Coufal, P.; Heyda, J.; Jungwirth, Pavel
Ústav organické chemie a biochemie, 2016

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 ...

Kašička, Václav; Koval, Dušan; Ibrahim, A.; Chamieh, J.; Cottet, H.
Ústav organické chemie a biochemie, 2016

Determination of stability constants of [Gly6]-antamanide complexes with small cations by affinity capillary electrophoresis
Pangavhane, Sachinkumar; 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 ...

Pangavhane, Sachinkumar; Makrlík, E.; Ruzza, P.; Kašička, Václav
Ústav organické chemie a biochemie, 2016

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 ...

Šolínová, Veronika; Štěpánová, Sille; Jančařík, Andrej; Klívar, Jiří; Šámal, Michal; Stará, Irena G.; Vacek Chocholoušová, Jana; Vacek, Jaroslav; Starý, Ivo; Kašička, Václav
Ústav organické chemie a biochemie, 2016

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 ...

Tůmová, Tereza; Monincová, Lenka; Čeřovský, Václav; Kašička, Václav
Ústav organické chemie a biochemie, 2016

Investigation of calix[4]arene-bis(t-octylbenzo-18-crown-6) complex with cesium cation by affinity capillary electrophoresis
Štěpánová, Sille; Moyer, B.; Makrlík, E.; Kašička, Václav
2016 - English
Affinity capillary electrophoresis (ACE) was employed for investigation of non-covalent interactions of calix[4]arene-bis(t-octylbenzo-18-crown-6) with Cs+ ion in methanol. The apparent binding constant of the calix[4]arene-bis(t-octylbenzo-18-crown-6)-Cs+ complex was determined from the dependence of the effective electrophoretic mobilities of the calix[4]arene-bis(t-octylbenzo-18-crown-6) on the concentration of cesium ion in the backround electrolyte using a non-linear regression analysis. The logarithmic form of the conditional apparent binding constant of calix[4]arene-bis(t-octylbenzo-18-crown-6)-Cs+ complex was found to be equal to 1.61. Keywords: affinity capillary electrophoresis; calix[4]arene-bis(t-octylbenzo-18-crown-6); binding constant Available at various institutes of the ASCR
Investigation of calix[4]arene-bis(t-octylbenzo-18-crown-6) complex with cesium cation by affinity capillary electrophoresis

Affinity capillary electrophoresis (ACE) was employed for investigation of non-covalent interactions of calix[4]arene-bis(t-octylbenzo-18-crown-6) with Cs+ ion in methanol. The apparent binding ...

Štěpánová, Sille; Moyer, B.; Makrlík, E.; Kašička, Václav
Ústav organické chemie a biochemie, 2016

Determination of stability constant of potassium-dibenzo-18-crown-6 complex in mixed hydro-organic solvents by affinity capillary electrophoresis
Konášová, Renáta; Jaklová Dytrtová, Jana; Kašička, Václav
2016 - English
Affinity capillary electrophoresis was applied to determination of apparent stability constant, Kst, of potassium-dibenzo-18-crown-6 complex in mixed hydro-organic solvents, i.e. mixtures of water with methanol, ethanol, propan-2-ol or acetonitrile. It was found that the Kst strongly depends on the solvent composition. The log Kst values linearly increase with decreasing molar fraction of water in the above hydro-organic solvent mixture. Keywords: affinity capillary electrophoresis; dibenzo-18-crown-6; stability constant Available at various institutes of the ASCR
Determination of stability constant of potassium-dibenzo-18-crown-6 complex in mixed hydro-organic solvents by affinity capillary electrophoresis

Affinity capillary electrophoresis was applied to determination of apparent stability constant, Kst, of potassium-dibenzo-18-crown-6 complex in mixed hydro-organic solvents, i.e. mixtures of water ...

Konášová, Renáta; Jaklová Dytrtová, Jana; Kašička, Václav
Ústav organické chemie a biochemie, 2016

Frustrated Lewis pairs-assisted reduction of carbonyl compounds
Marek, Aleš; Pedersen, M. H. F.
2016 - English
An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, absolute regioselectivity and the non-metallic character of the reagent, it provides an excellent tool for 1H, 2H as well as 3H chemistry. It is a new strategy for the one-pot synthesis of aromatic alcohols selectively labeled with heavy isotopes of hydrogen. Keywords: carbonyl compounds; frustrated Lewis parts; alcohol synthesis Available at various institutes of the ASCR
Frustrated Lewis pairs-assisted reduction of carbonyl compounds

An alternative and robust method for the reduction of carbonyl groups by frustrated Lewis pairs (FLPs) is reported in this paper. With its very mild reaction conditions, good to excellent yields, ...

Marek, Aleš; Pedersen, M. H. F.
Ústav organické chemie a biochemie, 2016

Analysis of novel members of FAHFA lipid class derived from omega 3-PUFA by LC-MS/MS and LC-MS/MS/MS
Rombaldová, Martina; Kuda, Ondřej; Březinová, Marie; Slavíková, Barbora; Pošta, Martin; Beier, Petr; Janovská, Petra; Veleba, J.; Kopecký Jr., J.; Kudová, Eva; Pelikánová, T.; Kopecký, Jan
2016 - English
White adipose tissue (WAT) is a complex organ with both metabolic and endocrine functions. Dysregulation of all of these functions of WAT, together with low-grade inflammation of the tissue in obesity, contributes to the development of insulin resistance and type 2 diabetes. Omega-3 polyunsaturated fatty acids (PUFA) of marine origin play an important role in resolution of inflammation and exert beneficial metabolic effects. Using LC-MS/MS method, we elucidated the structures of novel members of fatty acid esters of hydroxy fatty acids (FAHFA), which were present in murine and human serum and WAT after omega-3 PUFA supplementation in diet. These compounds contained DHA esterified to 9- and 13-hydroxyoctadecadienoic acid (HLA) termed 9-DHAHLA and 13-DHAHLA, and were synthesized in WAT. Our results document the existence of novel lipid mediators, which are involved in the beneficial anti-inflammatory effects attributed toomega-3 PUFA, in both miceandhumans. Keywords: branched fatty acid; lipidomics; mass spectrometry; omega 3-PUFA Available at various institutes of the ASCR
Analysis of novel members of FAHFA lipid class derived from omega 3-PUFA by LC-MS/MS and LC-MS/MS/MS

White adipose tissue (WAT) is a complex organ with both metabolic and endocrine functions. Dysregulation of all of these functions of WAT, together with low-grade inflammation of the tissue in ...

Rombaldová, Martina; Kuda, Ondřej; Březinová, Marie; Slavíková, Barbora; Pošta, Martin; Beier, Petr; Janovská, Petra; Veleba, J.; Kopecký Jr., J.; Kudová, Eva; Pelikánová, T.; Kopecký, Jan
Ústav organické chemie a biochemie, 2016

Enantioseparations of drugs and catalysts by partial-filling affinity capillary electrophoresis using helquats as chiral selectors
Růžička, Martin; Koval, Dušan; Vávra, Jan; Reyes Gutierrez, Paul Eduardo; Teplý, Filip; Kašička, Václav
2016 - English
Noncovalent molecular interactions between helquats, a new class of dicationic helical extended diquats and selected commonly used negatively charged chiral drugs and catalysts have been investigated using partial-filling affinity capillary electrophoresis (PF-ACE). Three types of interactions of analytes with helquats were observed: (1) medium strong enantioselective interactions, (2) medium strong non-enantioselective interactions and (3) no or very weak non-enantioselective interactions. Keywords: affinity capillary electrophoresis; helquats; chiral selector Available at various institutes of the ASCR
Enantioseparations of drugs and catalysts by partial-filling affinity capillary electrophoresis using helquats as chiral selectors

Noncovalent molecular interactions between helquats, a new class of dicationic helical extended diquats and selected commonly used negatively charged chiral drugs and catalysts have been investigated ...

Růžička, Martin; Koval, Dušan; Vávra, Jan; Reyes Gutierrez, Paul Eduardo; Teplý, Filip; Kašička, Václav
Ústav organické chemie a biochemie, 2016

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