The clouding points and equilibrium concentrations of PEG/dextran/water and PEG/ammonium sulfate/water systems were experimentally determined for different molecular weights of PEG by titration method and direct determination of concentrations. In phase diagrams of PEG-water with ammonium sulfate or dextran, the addition of salt or dextran induced the phase separation of PEG-rich phases near the PEG-lean phases having the different partitioning of PEG. The concentrations of PEG in PEF-rich phases increase as the amounts of PEG or salt and dextran increase, while the concentrations of PEG in aqueous media decease in any cases. the higher the molecular weight of peg has, the wider the two-phase regions are. In dextran DT10 systems, the partition coefficients of egg albumin into PEG-lean phases increase with concentrations of dextran and the molecular weight of PEG. In ammonium sulfate systems, the partitioning coefficients showed a maxi-mum, having lower partitioning at the very high and low concentration of salts. It is also observed that as the amounts of albumin increase, the partitioning of albumin into PEG-lean phase increases.
[References]
Albertsson PA, "Partition of Cell Particles and Macromolecules," 3rd ed., Wiley Interscience, N.Y., 1986