Novel ethyl lactate based ATPS for the purification of rutin and quercetin

Abstract

The application of new aqueous two-phase systems (ATPS) composed by a hydrophilic green solvent, ethyl lactate, and two low environmental impact salts: sodium and potassium citrate have been studied for the recovery of two flavonoids from aqueous solutions. First, to understand the phase formation process of the ATPS, binodal curves and tie-lines and their respective slopes and tie-line lengths were determined at T=298.15 K and atmospheric pressure. The degree of consistency of the tie-lines was evaluated using Othmer-Tobias and Bancroft equations. Moreover, the influence of the change of the salt cation on the phase behaviour has been assessed. Furthermore, the UNIversal QUAsiChemical (UNIQUAC) thermodynamic model was applied to describe the phase equilibria presented in this work. Furthermore, the partitioning of two flavonoids, rutin and quercetin, in these ATPS {ethyl lactate (1) + citrate salts (2) + water (3)} was measured at T = 298.15 K and atmospheric pressure. Finally, the obtained results were compared with those found in literature.