Patent ID: 7601545

Claim:
A method for preparing a macromolecule sample, comprising: automatically acquiring a liquid mixture, the mixture comprising a macromolecule, one or more rough components that are larger than the macromolecule, and one or more fine components that are smaller than the macromolecule; and automatically separating from the macromolecule at least a portion of the components by applying the mixture to each of a plurality of filter membranes, with a pressure differential across each filter membrane, the filter membranes comprising a rough filter membrane selected to separate at least a portion of the rough components and a fine filter membrane selected to separate at least a portion of the fine components; directing a liquid across the fine filter membrane in a direction opposite to the direction of filtration, the macromolecule thus being directed further in the apparatus for analysis; and directing a liquid across the rough filter membrane in a direction opposite to the direction of filtration for cleaning the filter membrane surface to restore the filter membrane characteristics and capacity to its initial state prior to separating the macromolecule.