  A new type of phase separation in the polyelectrolyte solutions consisting of
several types of charged macromolecules differing in their degree of ionization
is predicted via a general thermodynamic consideration. We show that even a
small difference in the degree of ionization of otherwise equivalent components
results in their spatial separation occurring upon decreasing the temperature
much earlier than precipitation of the components from the solution. Some
implications of charge fractionation in biological processes are discussed.

Soft Condensed Matter;Statistical Mechanics