The Effect of Temperature on Different Aqueous Two-Phase Diagrams of Polyethylene Glycol (PEG 6000, PEG 8000, and PEG 10000) + Potassium Sodium Tartrate + Water

Abstract

Phase diagrams and models of PEG 6000, PEG 8000, and PEG 10000 in water and potassium sodium tartrate systems were constructed at temperatures 10, 25, and 45 °C. These phase diagrams consist of binodal curves and tie-lines, modeled using the Merchuck equation, and validated using a linearized form of the Othmer–Tobias equation. It was observed that higher system temperatures produced larger binodal envelopes and better phase separation. It was also observed that smaller PEG molecular weights produced smaller binodal envelopes.

Phase Equilibria of Aqueous Two-Phase Systems of PEG with Sulfate Salt: Effects of pH, Temperature, Type of Cation, and Polymer Molecular Weight

“…The PEG characteristics, such as weight, size, and concentration, are primary factors in the properties of ATPS systems . Many researchers have reported on the effect of polymer on the formation of the aqueous two-phase systems diagrams . It is widely known that the partitioning behavior of biomolecules is greatly affected by their molecular mass.…”

“…Increasing the polymer weight reduces the free volume of the high phase, resulting in the partitioning of the biomolecules into the low salt-rich phase, and hence reduces the partitioning coefficient . In other words, the higher the molecular weight of the PEG, the larger the two-phase region created when mixed with similar salt concentrations …”

“…Among all of the components of aqueous two-phase systems (ATPS) including, e.g., polymers, ionic liquids, alcohols, salts, surfactants, sugars, among others, polymer–salt-based ATPSs are one of the most well-known components due to their simplicity, compatibility, and wide varieties. − Most reported research works on polymer–salt-based ATPSs are related to poly­(ethylene glycol) (PEG) and inorganic salts such as sulfate, − phosphate, , carbonate, , nitrate, or chloride . Poly­(ethylene glycol) possesses superior properties such as low toxicity, neutrality, excellent biocompatibility, and solubility in both aqueous and organic solutions. ,, The information for the phase behavior of the polymer/salt aqueous two-phase systems, therefore, has substantial significance in the applications for much biological and environmental process design. Besides, the well-known features of the kosmotropic sulfate salts, , in particular the Hofmeister series, provide significant insights into the protein stability in the extraction process as well as purification of biomolecules from other compounds. , …”

“…12 Poly(ethylene glycol) possesses superior properties such as low toxicity, neutrality, excellent biocompatibility, and solubility in both aqueous and organic solutions. 1,6,13 The information for the phase behavior of the polymer/salt aqueous two-phase systems, therefore, has substantial significance in the applications for much biological and environmental process design. Besides, the well-known features of the kosmotropic sulfate salts, 14,15 in particular the Hofmeister series, provide significant insights into the protein stability in the extraction process as well as purification of biomolecules from other compounds.…”

Extractive Fermentation Processes: Modes of Operation and Application

“…Two frequently used ATPSes are the polymer‐polymer systems, e.g. polyethylene glycol (PEG) and Dextran or a polymer‐salt systems, e.g., PEG/Phosphate, PEG/Sulphate and PEG/Citrate 109, 110. The solvation properties of these two phases are different – one being more polar and the other more non‐polar; on the basis of this difference, selective (and gentle) partitioning of biomolecules can be achieved.…”