Ištisinės ribotai pasiekiamos fazės kapiliarinei chromatografijai : daktaro disertacija : fiziniai mokslai, chemija (03 P)

Disert. rengta 2003-2007 m. Vytauto Didžiojo universiteteBibliogr.: p. 114-121Vytauto Didžiojo universiteta

The distinctive features of the rights and obligations of the subjects of labour law

Labour law distinguishes between these types of entities: the employee, the employer and the employees. The legal status of employee and the employer is related to legal employment relations. A public or private juridical person whose legal employment subjectiveness arises at the moment of the foundation may become an employer. The staff consist of the employees related to the employer by employment relations

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Peculiarities of organising provision of social services in non-governmental organisations

Vytauto Didžiojo universitetasŠvietimo akademij

Paprastesnė polimerinių nebirių nejudrių fazių su makrociklinio antibiotiko chiraliniu selektoriumi, skirtų elektrochromatografijai, sintezė

A simplified approach to synthesize nonparticulate (continuous or monolithic) beds with embedded vancomycin chiral selectors for capillary electrochromatography is proposed. In the present approach, N,N'-diallyltartardiamide monomer with diol functionality is used, which can be readily converted to aldehyde groups via periodate treatment. Parallel to the activation of the polymeric matrix for covalent attachment of vancomycin, the periodate treatment has shown secondary effects on the polymeric bed morphology, namely the increase of the average pore size and porosity of the skeleton. Inversed size-exclusion chromatography was applied to characterize porosimetric properties of the capillary columns before and after the periodate treatment. Electroosmotic and enantioselective properties of the nonparticulate beds synthesized are presented. The approach is of more general interest attaching different affinity groups to the polymeric matrix and/or enhancing the accessibility to the active sites, for instance, in the molecular imprinting techniqueVytauto Didžiojo universiteta

Determination of volatile and non-volatile products of milk fermentation processes using capillary zone electrophoresis and solid phase microextraction coupled to gas chromatography

The aim of the investigations was to develop analytical methods for the determination of selected volatile and non-volatile organic compounds numbering among the final products of milk fermentation. The analyzed compounds were as follows: biacetyl and carboxylic acids (formic, acetic, citric, and lactic). The model yogurt was prepared under controlled conditions in our laboratory by addition of the selected bacteria (Lactobacillus bulgaricus and Streptococcus thermophilus) to the milk sample. The temperature, time, and stirring were controlled during the fermentation process. Factors considered in SPMPE-GC-FID method development included fiber exposure time, salt addition, temperature of extraction, and temperature of desorption. Various SPME fibers, for example with PDMS, CAR/PDMS, PA, and PDMS/DVB coatings, were tested to obtain the highest recovery of the investigated compounds extracted from yogurt samples. Based on these preliminary experiments, qualitative and quantitative analyses for the determination of biacetyl were performed by SPME-GC-FID. Moreover, a capillary zone electrophoresis method was developed for the determination of carboxylic acids in the yogurt samples. The buffer composition as well as deproteinization by acetonitrile were found to have a crucial effect on the analysisVytauto Didžiojo universiteta

Migration of bacteria through a monolith

The separation of bacteria by electromigration techniques was a subject of several of our previous papers. This contribution presents the results of investigation of the porosity of the monolithic bed and migration of Staphylococcus aureus cells through it. The gigaporous monolith was thermally synthesized using glycidyl methacrylate, triethylene glycol dimethacrylate and trimethylol propane trimethacrylate as the monomers in the presence of porogen solvent containing 1-decanol. polyethylene glycol and 2-methoxyethanol. The porous properties were evaluated by inverse size-exclusion chromatography (ISEC) using a wide range of polystyrene standards of different molecular weights. The results have shown, that large pores (ca. 300 nm) dominate in the monolithic bed structure, however much larger flow-through pores must also be present as ca. 1 mu m sized S. aureus bacteria were able to migrate through the bed. (C) 2009 Elsevier B.V. All rights reservedBiochemijos katedraVytauto Didžiojo universiteta

Synthesis, characterization and application of restricted-access media for capillary liquid chromatography

Vytauto Didžiojo universiteta