Effect of temperature on the salting-out effect and phase separation in aqueous solutions of sodium tungstate and poly(ethylene glycol)

Ternary aqueous solutions of water soluble polymers and certain electrolytes separate into a polymer-rich and a salt-rich phase over part of the composition space. Aqueous two-phase systems of this nature are useful for the separation and purification of biomaterials where the employment of a nonpolar solvent/aqueous phase system would lead to degredation of biological activity [1,2]. Polyethylene glycol (PEG), which is a hydrophilic polymer, is often used in aqueous two-phase partitioning studies. In this work, the phase diagrams and LLE data have been determined for aqueous two-phase systems containing PEG and sodium tungstate at various temperatures. The effect of temperature on the phase diagrams and LLE data of investigated systems were studied.