Cell separations and subfractionations by countercurrent distribution in two-polymer aqueous phase systems depend on non-equilibrium conditions.

Certain kinetic aspects of the partitioning behavior of erythrocytes in dextran-poly(ethylene glycol) aqueous phase systems have been examined, and their implications for cell partitioning have been considered. It is concluded that the diverse and sometimes unique fractionations attained by use of multiple extractions (e.g., countercurrent distribution) of cells in two-polymer aqueous-phase systems depend on non-equilibrium conditions.