Aqueous biphasic systems formed in (zwitterionic salt+inorganic salt) mixtures

Abstract

The manuscript reports on a new class of aqueous biphasic systems (ABSs) formed in mixtures of inorganic salts (ISs) and zwitterionic salts (ZWSs). Aqueous ternary phase diagrams characterized by a binodal curve were determined for systems consisting of four ISs, K3PO4, K2HPO4, K2HPO4/KH2PO4, and K2CO3, and three structurally similar ZWSs differing in hydrophobicity. Comparison of phase behaviour of ABSs composed of ZWSs, ionic liquids (ILs) and zwitterions was provided. Potential of ZWSs based systems for extraction of aromatic molecules and amino acids, such as glycine, L-tryptophan, DL-phenylalanine, eugenol, and phenol was examined. Feasibility and limitations of isolation of products after partition and recovery of ZWS were discussed.