Number of found documents: 4
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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

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

Metodika užití jednorázového setu pro detekci měďnatých (Cu2+) iontů v pitných a průmyslových odpadních vodách
Stloukal, R.; Vopálenská, I.; Watzková, J.; Gregušová, B.; Palková, Z.; Váchová, Libuše; Pichová, Iva
2014 - Czech
Metodika shrnuje aktuální legislativní požadavky a normy související s obsahem měďnatých (Cu2+) iontů v pitných a průmyslových odpadních vodách. V metodice je dále podrobně popsán nově vyvinutý jednorázový detekční set LentiKats, který je založen na detekci měďnatých iontů pomocí Biokatalyzátoru lentikats s imobilizovanými rekombinantními kvasinkami. The methodology summarizes the current legislative requirements and standards related to the content of cupric (Cu2+) ions in drinking waters and industrial wastewaters. In this methodology, a newly developed single detection LentiKats set, is described in detail. The test is based on the detection of cupric ions using Lentikats Biocatalyst with immobilized recombinant yeasts. Keywords: Lentikats Biocatalyst; cupric ions; detection; drinking waters; industrial wastewaters Fulltext is available at external website.
Metodika užití jednorázového setu pro detekci měďnatých (Cu2+) iontů v pitných a průmyslových odpadních vodách

Metodika shrnuje aktuální legislativní požadavky a normy související s obsahem měďnatých (Cu2+) iontů v pitných a průmyslových odpadních vodách. V metodice je dále podrobně popsán nově vyvinutý ...

Stloukal, R.; Vopálenská, I.; Watzková, J.; Gregušová, B.; Palková, Z.; Váchová, Libuše; Pichová, Iva
Ústav organické chemie a biochemie, 2014

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