The present invention is directed to processes of separating, analyzing and/or collecting selected species within a target sample by use of magnetic microspheres including magnetic particles, the magnetic microspheres adapted for attachment to a receptor agent that can subsequently bind to selected species within the target sample. The magnetic microspheres can be sorted into a number of distinct populations, each population with a specific range of magnetic moments and different receptor agents can be attached to each distinct population of magnetic microsphere.
STATEMENT REGARDING FEDERAL RIGHTS
 This invention was made with government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The government has certain rights in the invention.