CONSOLIDATION OF THE PACKING MATERIAL IN CHROMATOGRAPHIC COLUMNS UNDER DYNAMIC AXIAL-COMPRESSION .1. FUNDAMENTAL-STUDY

Packing materials do consolidate progressively inside chromatographic columns. The process is slow. The literature on the phenomenon of soil consolidation is critically reviewed and the concepts relevant to the behavior of sands are applied to conventional packing materials. Preliminary experimental results obtained with irregular-shaped particles are presented to illustrate the concepts introduced by and the conclusions of the literature survey. These results show that the consolidation of packing material in chromatographic columns is a slow process which may sometimes appear to take place as a series of ''catastrophic'' events. It involves changes in the apparent packing density of the bed which are large enough to account for the formation of large voids at the column inlet, as has been frequently reported by operators of analytical as well as large-size preparative columns.