STUDY OF THE PACKING BEHAVIOR OF RADIAL COMPRESSION COLUMNS FOR PREPARATIVE CHROMATOGRAPHY

The behavior of the packing of radial compression preparative columns (17.5 x 7.5 cm) was studied using C-18 silica IMPAQ as the stationary phase and water-methanol solutions as the mobile phase. The retention volumes of phenol and cresol and the efficiency of their peaks were repeatedly measured on three different columns, over several hundred hours, during which repeated water-methanol gradient runs were conducted. No significant changes in the retention factors and the column efficiency were observed during the testing period. The effects of the mobile phase temperature and of the radial compression pressure on the column efficiency were also studied. The external porosity and the permeability of the packing were found to decrease slowly with increasing compression pressure. Finally, a set of experiments were performed to trigger the formation of channels and to show their possible repair by applying elevated radial compression pressures.