Capillary electrophoresis study on evolution of phase of mixed micelles

Abstract

Capillary electrophoresis (CE) coupled with the contactless conductivity detector (C4D) was applied to characterize the transformation (TX-100, SDS) → TX-100/SDS. Three states of the TX-100/SDS micelle were established due to transformation, i.e. the cluster state, highly mobile homogeneous micelles obtained from the phase (TX-100 (2.5–3.5%)/SDS (0.04–0.1 M)); the state of polydispersity, i.e. polydisperse micelles with the lower mobility obtained from the phase (TX-100 (7%)/SDS (0–0.1 M); and the state of metastability at high content of SDS surfactant in TX-100/SDS phase. It was established that these states cover two different regions in the phase evolution according to descriptors used to characterize the phase of mixed micelles. The detected cluster state was wider characterized, and for this, the electrophoretic data were converted into micelle characteristics. By higher viscosity of the background electrolyte (BGE), new situations in the evolution of the TX-100/SDS phase were visualized, especially the transformation of a state of the metastability of a mixed micelle. Based on the obtained results, the two segment/segment systems, based on mixed micelles, were proposed. It was found that only one of the systems was able to exchange micelles between two micellar segments during the electrophoretic run and the issue was explained taking into account the obtained in the work results.