Vera Pacakova - Academia.edu (original) (raw)

Papers by Vera Pacakova

Journal of Chromatography A, 2005

Three stationary phases have been prepared for affinity liquid chromatography isolation and separ... more Three stationary phases have been prepared for affinity liquid chromatography isolation and separation of porcine and human pepsin. The phases contain 3,5-diiodo-L-tyrosine (DIT) bound to the supports HEMA BIO VS, HEMA BIO E and EPOXY TOYOPEARL. These phases have been tested on a model sample of porcine pepsin A and applied to human pepsin. Fractions have been collected and the chymase activity determined in selected analyses. For affinity CE, capillaries have been prepared by modifying the wall with 3-aminopropyltriethoxysilane, followed either by direct binding of DIT, or by binding L-tyrosine that was subsequently iodated. The dissociation constant K(d) has been determined for the pepsin-DIT complex from the changes in the electrophoretic mobilities.

Journal of Chromatography B: Biomedical Sciences and Applications, 1996

Chemicke Listy, 2002

A GC-MS/MS method for determination of the title compounds was developed, validated and applied t... more A GC-MS/MS method for determination of the title compounds was developed, validated and applied to biotic samples. Standard purification procedures developed for analysis of polychlorinated dibenzodioxines or dibenzofurans were used. Using the isotope dilution method, a good repeatability was attained even at low concentrations.

Journal of High Resolution Chromatography, 2000

Journal of Separation Science, 2004

Topography and thickness of hydrophilic polymer coatings of fused-silica capillaries for capillar... more Topography and thickness of hydrophilic polymer coatings of fused-silica capillaries for capillary electrophoresis (CE) were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), and profilometry. Three hydrogels, poly(2-hydroxyethyl methacrylate) [poly(HEMA)], poly(diethylene glycol monomethacrylate) [poly(DEGMA)], and poly(triethylene glycol monomethacrylate) [poly(TEGMA)], were deposited using two procedures, either by simple physical sorption of the polymers, or by derivatization of the capillary wall surface with glycidyl methacrylate (EPMA) followed by polymerization of the appropriate monomers. The performance of the modified capillaries was tested under CE conditions (decrease in the electroosmotic flow, EOF dependence on pH, separation of milk and standard proteins). It has been found that the most important property of the polymer coating is its thickness, whereas its topography and the degree of its hydrophobicity are less significant. Film deposition by physical adsorption is preferable to polymerization on the derivatized surface.

Journal of Biochemical and Biophysical Methods, 2007

Electroanalysis, 1989

ABSTRACT

ELECTROPHORESIS, 2002

Modification of capillary electrophoresis (CE) capillaries by poly(hydroxyethyl methacrylate) (po... more Modification of capillary electrophoresis (CE) capillaries by poly(hydroxyethyl methacrylate) (poly(HEMA), poly(diethylene glycol monomethacrylate) (poly(DEGMA) and poly(triethylene glycol monomethacrylate) (poly(TEGMA), was studied. Methods based on physical adsorption of the modifier and on its chemical binding were compared on the basis of the electroosmotic flow (EOF) reproducibility, the EOF dependence on the pH, the symmetry of the peak of positively charged tyramine, the stability of the coating and the separation of standard and milk proteins in the modified capillaries. Reproducible coatings were obtained by chemical binding of the polymers to the capillary walls and by coating with a solution of a polymer, as also demonstrated by the atomic force microscopy.

Journal of Chromatography A, 1979

Journal of Chromatography A, 1976

Journal of Chromatography A, 1988

Chemosphere, Sep 30, 2004

Journal of Chromatography a, May 1, 1995

Talanta, 1997

A simple technique has been developed for preconcentration of gaseous trace organic compounds on ... more A simple technique has been developed for preconcentration of gaseous trace organic compounds on solid sorbents, followed by gas chromatography. The sorbent is packed in a cartridge from a syringe needle placed in the gas chromatographic injector and the analytes previously adsorbed are thermally desorbed at the injector temperature and then directly swept by the carrier gas into the column. The system has been tested for a charcoal-based adsorbent and silica gel, with pentane, methanol, ethanol and acetone as the model analytes. The procedure is rapid, the detection limits vary from a few nmol l(-1) to values below 0.1 nmol l(-1) (i.e., a few ppb), the linear dynamic range amounts to at least five concentration decades and a typical relative standard deviation is 10% at the nmol l(-1) concentrations. It has been shown that the method is readily applicable to determination of instantaneous concentrations of the analytes in natural and industrial atmosphere and to their monitoring in...

The present state of the use of separation techniques in the identification and characterization ... more The present state of the use of separation techniques in the identification and characterization of allergens and in the monitoring of the quality of allergenic preparations is critically surveyed. After a brief summary of the range of problems encountered in obtaining and in the application of allergenic preparations and of the principal physico-chemical properties of allergens, chromatographic and electromigration methods of separation of components of these systems and their combinations with immunochemical procedures are discussed, with selected examples of application to real materials. Emphasis is placed on evaluation of the most important analytical parameters, such as reliability of the results, separation efficiency and resolution, and on the most recent results in the field.

Journal of Separation Science, 2007

Journal of Chromatography a, Sep 2, 1994

Journal of Separation Science