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Focusing Approaches with Alkyl Sulfates and Perfluorinated Carboxylic Acids Micelles in Aqueous-Organic Environment
Autoři: Váňová Jana | Michalíková Jana | Moravcová Martina | Česla Petr
Rok: 2018
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng Focusing Approaches with Alkyl Sulfates and Perfluorinated Carboxylic Acids Micelles in Aqueous-Organic Environment Focusing of the sample in the capillary electrophoresis can be realized by several approaches, i.e. utilizing pH effects, transient isotachophoresis, or mechanisms based on the interactions of analytes with micelles (sweeping approaches). The main idea of the last mentioned technique is the use of a pseudostationary phase to gather the dispersed neutral or charged analytes into narrow zones as well as to achieve sensitivity enrichment [1]. From this point of view, the knowledge of the critical micelle concentration of the surfactant is essential to provide suitable conditions for sweeping – the presence of the micelles in the solution. The critical micelle concentration, the concentration when the micelles are formed in the solution of surfactant, is dependent on the properties of the solution (composition, pH, content of organic modifier, temperature). This work is focused on the determination of critical micelle concentration of sodium alkyl sulphates and perfluorinated carboxylic acids in the aqueous solutions, in the solutions with addition of acetonitrile, and on the determination of migration characteristics of natural antioxidants in micellar systems. In general, the critical micelle concentration increases with increasing content of acetonitrile in the solution (aggregation number is decreasing), at the same time, the retention factor of the analytes decreases with increasing concentration of organic modifier in the solution because the increasing of hydrophobicity decreases the analyte-micelles affinity. Both effects have been studied with the aim of achieving efficient focusing applicable in multidimensional separations.