Recent Advances in Column Technology

Abstract

Abstract Over the past half century, there has been a substantial development in the modern chromatography column. Particle sizes have decreased from 10 to now sub‐2 μm, and with it the number of theoretical plates has increased to about 200 000 per meter on fully porous particles, and 250 000 plates per meter for core–shell particles. Despite this change, the number of plates used per separation has not changed that much, since shorter columns must be used when packed with the smaller particles because a great deal more pressure is required to drive mobile phase through the column. One significant change, however, is that separations have got faster as a result of the decrease in particle size. Nevertheless, over time, one fundamental problem still exists; packed beds are heterogeneous, and this is a source of performance loss. To overcome the consequences of packing heterogeneity, a new column technology has been developed, which is called active flow technology ( AFT ). This technology minimizes the significance of the wall effect and provides much greater separation efficiency, while enabling faster separations, especially when coupled to MS detection. This chapter highlights the causes of column bed heterogeneity and presents active flow technology columns, illustrating briefly some of the new directions that the development of this column technology can take.