Compositional Heterogeneity in Anionic/Nonionic Mixed Micelles Observed by Frontal Analysis Continuous Capillary Electrophoresis

Abstract

Mixed micelles of sodium dodecyl sulfate (SDS) with Triton X-100 (TX100) or dodecyl octa(ethylene glycol) monoether (C12E8) at different bulk SDS mole fractions (Y) and at two ionic strengths were analyzed by frontal analysis continuous capillary electrophoresis. For most systems, the electropherograms showed a distribution of mobilities, providing evidence of compositional heterogeneity in the mixed micelles. From the empirical relationship between average mobility and Y, the mobility distributions may be interpreted in terms of a distribution of micelle compositions. Broad distributions were observed from 0.1 ≤ Y ≤ 0.6 in all cases, while the mixed micelles were close to monodisperse at Y ≥ 0.8. As similar results were obtained from monodisperse C12E8 and polydisperse TX100, the compositional distributions do not result from the compositional polydispersity of the nonionic surfactant. These results were found to be correlated with the composition dependence of the critical micelle concentration of mixed micelles.

Effects of Polyelectrolyte Chain Stiffness, Charge Mobility, and Charge Sequences on Binding to Proteins and Micelles

“…Previous studies 39,40 on surface potential and mobility of ionic/nonionic surfactants did in fact reveal a plateau in mobility at high ionic surfactant composition, which was attributed to micelle counterion condensation. The plateau onset at Y > 0.8 was, however, above nearly all the Y c values in this study.…”

Characterization of CdSe nanocrystals coated with amphiphiles. A capillary electrophoresis study

“…These are: the presence of a plug—thus a segment of phase of mixed micelles in between BGE, high affinity of these NCs to a phase of micelles and additional coating of these NCs with amphiphiles during a run. On the other hand, the migration phenomena observed in the present work may be a special case of mixed micellar system, already analyzed by capillary electrophoresis [ 45 , 46 ]. This is because CdSe/amphiphile NCs can be regarded as micelle-like objects able to form stable phase with regular micelles as concluded from the first part of the present work and refs.…”

“…[ 18 – 20 ]. It was reported, that peaks of various fractions of mixed micelles with mobility between 0 and −3.5 × 10 −4 cm 2 V −1 s −1 were observed, depending on polydispersity in terms of size and composition of mixed micelles [ 45 , 46 ]. The same can be concluded from ref.…”

Frontal Analysis Continuous Capillary Electrophoresis Study on the Interaction of an Amphiphilic Alternating Copolymer with Triton X-100

“…Figure 1(a) shows examples of FACCE data for mixtures of 1 g/L Mal/C12-2 and varying concentrations of TX. The FACCE data in this figure were differentiated to obtain distributions of migration times, which correspond to conventional capillary electropherograms ( Figure 1(b) ) [ 34 – 36 ]. In Figure 1(b) , signals at a migration time of ca.…”