Comparison of Salt Cations in the Design of Nonionic Surfactant Based Aqueous Biphasic Systems: Application in Polyphenol Separations

Abstract

New aqueous biphasic systems (ABSs) composed of a nonionic surfactant, Brij 35, and sulfate salts of Na, Mg, and Zn were designed. Ternary phase diagrams were constructed together with respective tie lines. The tie line lengths and slope of tie lines were calculated, and the results were validated using Othmer-Tobias and Bancroft equations. The binodals plotted for the three individual salts indicate their respective biphasic regions which follows the order MgSO 4 > ZnSO 4 > Na 2 SO 4 . All three ABSs were checked for their binary separation ability for the two polyphenols catechin and hesperidin. A pH dependent study indicates the possibility of separation of the two polyphenols using MgSO 4 as the salt rich phase.