Polymeric Aqueous Two Phase System with an Immobilized Phase by Cross-Linking

This work studies the modeling of polymeric aqueous two-phase systems (ATPS) with an immobilized phase. As the model system, the ATPS composed of polyethylene glycol (PEG) and Dextran was analyzed, whereas Dextran was immobilized. The model approach is based on the Koningsveldt-Kleintjens model forming the backbone of the swelling model. To model the ATPS with the immobilized phase, a novel incompressible elastic term is introduced considering the elastic limit of the dextran chains. At first, the ATPS with free PEG and dextran chains was modeled with the Koningsveldt-Kleintjens model and a good accordance to the experimental data was found. Afterward, the Koningsveldt-Kleintjens model was combined with the developed elastic term. A sensitivity analysis of the model was conducted to identify the important model parameters. To verify the model, experiments were performed to analyze the swelling of the immobilized dextran and the sorption of the amino acid L-serine in the immobilized phase. Thereby, the swelling and the sorption of L-serine in the immobilized phase could be modeled in good accordance to the experimental data.