Compartmentalized field flow fractionation

A flow field flow fractionator comprising a channel containment means, a base plate element, a permeable segmented frit, a permeable membrane, a top plate element and a sealing means, where

• A. said base plate element contains a plurality of distinct compartments open from above and fabricated to lie within said base, each of said distinct compartments having
• a. an opening lying in the same plane parallel to the base of said base plate;
• b. an exit port within each compartment permitting outflow therefrom of fluid that had entered it through said permeable membrane and corresponding fit segment lying thereover;
• c. fluid connection means from each such exit port to an independent fluid flow controlling means by which said outflow from each corresponding compartment may be controlled, permitting thereby the independent control of corresponding transverse flow on a sample aliquot as it moves over said corresponding compartment;
• in this manner, providing independently cross flow fields at each segmented region of said channel containment means;
• B. elements of said permeable segmented frit lie on top of said compartment openings in said base plate with each said frit element covering a corresponding compartment thereunder;
• C. said permeable membrane covers said segmented frit elements;
• D. a spacer means on top of said permeable membrane from which has been cut out a section providing thereby said channel containment means, bounded on all sides by the remaining region of said spacer, said channel containment means spanning the segmented frit elements lying below said permeable membrane;
• E. said top plate element lies on top of said spacer means sealing said channel containment means therefrom and providing three ports suitably positioned over said channel cutout;
• to permit, sequentially
• i. flow through of a mobile phase,
• ii. injection of said sample aliquot,
• iii. flow out of said sample that has been driven through said channel containment means by said mobile phase flow;
• F. said sealing means restricts fluid introduced into said channel containment means to flow therethrough or transverse to said channel containment means through said permeable membrane and said supporting frit elements into compartments thereunder.