The use of permeable packings in perfusion chromatography for protein separation is reviewed. Mass transport mechanisms in large-pore materials include forced convection in addition to diffusive transport. The key concept in perfusion chromatography is the ''augmented'' diffusivity by convection which explains the improved efficiency of perfusive packings compared with conventional supports. An extended Van Deemter equation has to be applied when calculating the height equivalent to a theoretical plate (HETP) of chromatographic columns with flow-through particles. It is shown that the effect of forced convective flow in pores is to drive the separation performance between diffusion-controlled and equilibrium limits. A methodology to understand mass transfer mechanisms in permeable packings is proposed. Experimental results for protein separation by high-performance liquid chromatography in new packing media are discussed Simulated moving bed technology is addressed. (C) 1997 Elsevier Science B.V.
