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Determination of critical micelle concentration of sodium alkyl sulphates and perfluorinated carboxylic acids in volatile buffers by capillary electrophoresis
Authors: Váňová Jana | Michalíková Jana | Smetanová Zuzana | Česla Petr
Year: 2017
Type of publication: ostatní - přednáška nebo poster
Page from-to: nestránkováno
Titles:
Language Name Abstract Keywords
eng Determination of critical micelle concentration of sodium alkyl sulphates and perfluorinated carboxylic acids in volatile buffers by capillary electrophoresis Many separation processes utilize presence of the surfactant in the separation medium. The knowledge of the critical micelle concentration of the surfactants is crucial to characterise the mechanism of the separation process. From this point of view we focused on the determination of the critical micelle concentration of sodium alkyl sulphates and perfluorinated carboxylic acids in the volatile buffers. There are several approaches to determine the critical micelle concentration; the methods may be based on the measurement of the surface tension, viscosity, density, turbidity etc. In this work, capillary electrophoresis was used for the determination of critical micelle concentration. Sodium alkyl sulphates, including sodium dodecyl sulphate, are widely used as pseudostationary phases in micellar electrokinetic chromatography. The connection of micellar electrokinetic chromatography with mass spectrometry offers the possibility of separation and structure elucidation of analytes. The problem of the connection lays in the presence of the non-volatile surfactants in the background electrolyte, which can contaminate mass spectrometer and suppress the signal of an analyte. This problem can be solved by partial-filling of the separation capillary using background electrolyte with the nonvolatile surfactants, which prevents introduction of pseudostationary phase into the ion source [1]. The next possibility is using volatile surfactants, e.g. perfluorinated carboxylic acids [2,3]. In this work, the critical micelle concentration of sodium alkyl sulphates and perfluorinated carboxylic acids in volatile buffers were determinate. The methods based on the measurement of current, retention time, retention factor, mobility and relative viscosity were tested. The values of critical micelle concentration obtained by different methods were compared and the differences among them were statistically evaluated.