Aqueous two-phase extraction system of sodium perfluorooctanoate and dodecyltriethylammonium bromide mixture and its application to porphyrins and dyes

Abstract

A new aqueous two-phase system is developed consisting of sodium perfluorooctanoate (SPFO) and dodecyltriethylammonium bromide (C 12NE) cationic–anionic surfactant mixture. The two phases with a clear interfacial boundary formed when SPFO to C 12NE molar ratio is 1.2:1 in the presence of 5% (v/v) nitric acid. The top phase is transparent and the bottom phase is opalescent. Extractions of dyes, porphyrin compounds with the two-phase system were performed. The results show that hydrophobic molecules were extracted into the surfactant-rich bottom phase with high extraction efficiencies. Positively charged porphyrins were extracted into the bottom phase with higher extraction efficiencies than negatively charged porphyrins. Such a new anionic surfactant two-phase system would be complementary to the C 12NE–SDS (sodium dodecyl sulfate) cationic two-phase which has been proven to be effective for extractions of porphyrins with substituted groups like carboxyl or sulfonic acid groups.