PREDICTING PARTITION-COEFFICIENTS IN POLYETHYLENE-GLYCOL POTASSIUM PHOSPHATE AQUEOUS 2-PHASE SYSTEMS

Partition coefficients in polyethylene glycol-potassium phosphate aqueous two-phase systems are predicted using a previously developed mathematical model. The model is based on a simplification of equations which arise from an osmotic pressure virial expansion and relates the partition coefficient to the concentration difference between phases of one of the phase-forming components and to the solute hydrophobicity. The predicted partition coefficients are compared to experimental values for several different solutes in this phase system over the range of pH of 5.5 to 9.2. The predictions are generally good for uncharged solutes, but show disagreement with experimental values for charged solutes.