Determination of Critical Micelle Concentration Values Using Capillary Electrophoresis Instrumentation

Abstract

The purpose of this work is to demonstrate the usefulness of capillary electrophoresis (CE) instrumentation for determining values of critical micelle concentration (cmc) of surfactants. The approach essentially consists of a CE version of the traditional method of measuring values of cmc by conductivity. Namely, the different conductivities of ionic surfactants in solution depending on their aggregation state, i.e., as monomers or micelles, and the effect on the electrical current as usually measured in a CE apparatus are employed to determine the cmc values. The cmc of sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) is obtained in several media such as water, aqueous solutions containing salts, organosaline solutions, and aqueous solutions containing β-cyclodextrin. The cmc values for SDS and CTAB under these conditions are in good agreement with those reported in the literature. Advantages and drawbacks of this procedure as well as its implications in micellar electrokinetic chromatography are discussed. From our results, it is deduced that the present method can be used with high confidence to determine values of cmc in a fast and easy way.

Probing competitive interactions in quaternary formulations

“…As outlined in Table 1a, the CMC of pure SDS (empty squares) is 7.9 mM which agrees well with earlier reported data [30][31][32]. In the presence of 0.5 wt% of the polymer, the CMC of SDS is lowered significantly from 7.9 mM to 1.2 mM, such decrease in the CMC could be understood as the aggregation of the SDS on the polymer.…”

Effect of Sodium Dodecyl Sulfate Adsorption on the Behavior of Water inside Single Walled Carbon Nanotubes with Dissipative Particle Dynamics Simulation

“…The SDS concentration in our report was higher than its CMC. From experiment, it showed that CMC of SDS surfactant is around 8.1-8.4 mM (equivalent to 0.23 wt %) [35]. In our DPD calculation, CMC of surfactant was determined by counting the number of free molecules in the solution.…”

Synthesis and Characterization of a New Cationic Surfactant Derived from 5-Chloro-1H-indole-2,3-dione In Aqueous Systems

“…It is well known that surfactant molecules are associated with micelles which begin to form above the critical micellar concentration (CMC) [19][20][21][22]. Numerous factors such as the addition of electrolytes [23][24][25], the pH of the buffer [26], the temperature [27,28], the addition of organic modifiers [29,30] Ionic strength of the aqueous solution [31,32], the presence of additives etc., make this value different from that determined in pure water.The determination of the CMC takes place in several ways such as the tensiometry which records the decrease in the surface tension as a function of the surfactant concentrations up to a limit beyond which the surface tension no longer decreases, and other methods used as conductivity [33][34] for charged surfactants, spectrofluorometry, nuclear magnetic resonance and UV-visible absorption spectroscopy [35][36][37].In the present work, we describe the synthesis of a new surfactant monomer derived from 5-Chloroisatin via the N-alkylation method under the conditions of phase transfer catalysis followed by the quaternizationof 1-(6-bromohexyl) 5 …”