Packings and stationary phases in preparative column liquid chromatography

Although the theoretical treatment of chromatographic processes on a preparative scale provides guidelines to the extent to which packing and stationary phase properties affect the target quantities such as sample input, throughput and resolution times sample input, a series of additional criteria were established to judge the quality of a packing in preparative column liquid chromatography. These include bed stability and flow resistance, chemical resistance and purity, solute accessibility, mass and biological recovery, fouling, regeneration and cost. Applying these criteria, the relative importance of physical and chemical structure parameters of packings and stationary phases was assessed. Commercial packings with mean particle diameters dp greater than 20 micron were listed for adsorption, size exclusion, ion-exchange and affinity chromatography. An analysis of the characteristic features of phase systems showed that adsorption media offer a high selectivity combined with adequate loadability, whereas ion exchangers and affinity media were best suited for biospecific solutes, particularly biopolymers, which can be attributed to their high selectivity and loadability.