Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9743496 | Analytica Chimica Acta | 2005 | 6 Pages |
Abstract
Critical micelle concentration (CMC) of sodium dodecyl sulphate (SDS), lithium perfluorooctanesulfonate (LPFOS), hexadecyltrimethylammonium bromide (HTAB), tetradecyltrimethylammonium bromide (TTAB), and sodium cholate (SC), surfactants commonly used as pseudostationary phases in micellar electrokinetic chromatography (MEKC), have been determined by means of three different methods: MEKC, spectrophotometry, and conductometry. Determinations have been performed in water, and also in different concentrations of phosphate buffer at pH 7.0. CMC values ranging from 8.08 (water) to 1.99 (50Â mM phosphate buffer) mM for SDS, from 7.16 (water) to 2,81 (30Â mM phosphate buffer) mM for LPFOS, from 3.77 (water) to 1.93 (20Â mM phosphate buffer) mM for TTAB, from 0.91 (water) to â¼0.34 (20Â mM phosphate buffer) for HTAB, and around 13Â mM (20Â mM phosphate buffer) for SC, are obtained. The effect of the electrolyte concentration on the CMC, as well as the linear relationship between the electrolyte counter-ion concentration and the CMC are discussed. This linear relationship provides an easy way for users to estimate the CMC of a MEKC system, at a given electrolyte concentration. A comparison between experimental methods, as well as a discussion about the suitability of a given method for the determination of the CMC for a given surfactant system is also provided.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Elisabet Fuguet, Clara Rà fols, Martà Rosés, Elisabeth Bosch,