The osmosedimentation effect: its application to chemical and biochemical separation

1. The fundamentals of the osmosedimentation effect are reviewed and its applications to chemical and biochemical separation problems are presented. 2. The osmosedimentation effect (solute sedimentation enhanced by osmotic and reverse-osmotic solvent mass currents spontaneously generated within a vertical dialysis cell) may be described by using standard treatments of non-equilibrium thermodynamics. 3. This effect allows many hitherto unfeasible or very difficult experiments to be performed: polymer and particle MW determination, under gravity or low-speed (1000-5000 rpm) centrifugation; dissolved protein concentration, by low-speed centrifugation; density gradient generation, at low centrifugation speeds; fast separation of fine particles; particle concentration and fractionation, under gravity and low speed centrifugation. 4. Osmocentrifugation methods may be easily implemented in any laboratory, as their requirements are: the availability of standard centrifuges and rotors, inexpensive dialysis cells and cellulose acetate membranes, which can be prepared in the laboratory.