Patent ID: 7077942

Claim:
A method of selectively removing a non-pathogenic biological contaminant from a mixture containing a compound and the contaminant comprising: (a) placing the compound and the contaminant mixture in a first solvent stream, the first solvent stream being separated from a second solvent stream by a selective membrane having a defined pore size; (b) selecting a buffer for the first solvent stream having a required pH; (c) applying an electric potential across the first and the second solvent streams, wherein at least a portion of the compound moves through the membrane into the second solvent stream while the contaminant is substantially retained in the first solvent stream, and substantially all transmembrane migration of the compound is initiated by application of the electric potential; (d) optionally, periodically stopping and reversing the electric potential whereby at least a substantial portion of the contaminant having entered the membrane moves back into the first solvent stream, while any of the compound that has entered the second solvent stream does not re-enter the first solvent stream; and (e) maintaining step (c), and optional step (d) if used, until the second solvent stream contains the desired purity of the compound.