Separation of nonionic surfactants of the polyoxyethylene type by capillary electrophoresis

Nonionic surfactants are widely used in commercial formulations as complex mixtures requiring efficient and selective separation methods. Capillary electrophoretic separations were carried out in electrolytes containing high amounts of organic solvents and anionic surfactants based on the formation of association complexes between analytes and anionic surfactants without micelle formation. Octyl- and nonylphenol polyethoxylates were separated as their ethoxylate homologues. Influences of the electrophoretic conditions like electrolyte concentration and pH, type and content of anionic surfactant and organic solvents were investigated.