Theoretical and experimental investigation of mass transfer in aqueous two-phase systems based on linear and branched polymers

In this work the mass transfer of the amino acid, L-serine, in two different aqueous two phase systems (ATPS) was analysed. One ATPS is based on a hyperbranched polyesteramide and dextran T40 and the second one is formed by polyethylene glycol and dextran T40. The mass transfer was analysed experimentally and theoretically as well. The experimental analysis of the mass transfer was carried out in a Nitsch cell; whereas the mass transfer across the interface was modelled by the density gradient theory providing an expression for the chemical potential in the inhomogeneous region. As thermodynamic model the Lattice Cluster theory was used to account for the structure of the polymers. To consider the association, it was combined with a Wertheim approach. The mass transfer approach based on the density gradient theory was extended to a quaternary system for the first time and applied to model the mass transfer of L-serine in both ATPS. It was found that L-serine enriches at the interface during the mass transfer. The developed mass transfer approach was successfully applied to model the interfacial mass transfer of L-serine in both ATPS. (C) 2018 Elsevier B.V. All rights reserved.