The wall effect is a serious cause of the loss of performance in chromatographic separations: Near the wall solute bands tail due to a higher packing density of particles: At the wall, solute bands front because of the geometrical orientation of rigid particles against a rigid wall. The wall effect can be eliminated by undertaking injections in an infinite diameter mode. Recently we introduced a new mode of chromatography, termed Active Flow Technology (AFT). In AFT an infinite diameter column is established whereby the sample is introduced into the column through an annular frit housed in a multiport header that enables sample and mobile phase to be loaded into the radial central region of the column, and pure mobile phase to be loaded into the outer radial region of the inlet, effectively establishing a curtain flow of mobile phase surrounding the sample. At the column outlet, the same fitting is employed. Sample that elutes in the radial central region of the bed is isolated from sample that elutes near the wall and elutes in a higher concentration sample zone with greater ‘efficiency’. This type of column is ideal for applications in LC-MS, since the volume load to the MS is reduced, and the concentration is higher. In this presentation the AFT concept is illustrated.