Effect of pH on the formation of Deep-Eutectic-Solvent-Based Aqueous Two-Phase systems
This project evaluates the effect of pH on the formation of Deep-Eutectic-Solvent-Based Aqueous Two-Phase system and can give insight on the partition behavior of bioactive compounds in these systems thus allowing to infer on the potential application of these system in separation of different bio-molecules.
Deep eutectic solvent (DES) is a new type of green solvent that can be used in an aqueous twophase system (ATPS). Nevertheless, there are some limitations on DES-ATPS. This is due to the formation of DES that required suitable stoichiometric partition between the two aqueous phases, hydrogen-bond acceptor (HBA) and hydrogen-bond donor (HBD). Otherwise, , hydrogen-bond acceptor (HBA) and hydrogen-bond donor (HBD) cannot form DES. In this study, the best DES system was selected through some lab experiments by testing four different combination of DES examine the effect of pH on the formation of DES-ATPS. After the stoichiometric partition was selected, DES-ATPS can be constituted by adding dibasic potassium phosphate salt solution. By forming the DES-ATPS, it has the potential liquid-liquid system to extract and separate of biomolecules. To investigate the pH value effects on phase equilibrium and formation of DES-ATPS, the DES-ATPS solution was assessed at room temperature and pH 5,7 and 9. Moreover, the partition coefficient and extraction efficiency of gallic acid and caffeine in DES-ATPS were studied allowing inferences to be made on the potential application of the systems. It was found that the change on pH value impacted on the formation DES-ATPS and chemical form of citrate salt. Overall, the effect of pH will affect the formation of DES-ATPS based on different target compounds. Different target compounds had their own suitable stoichiometric partition for the formation of DES-ATPS system. Therefore, the change of pH may help to adjust the stoichiometric partition to form DES solution, the formation of ATPS, and changing of biomolecules partition behavior.