THE EFFECTS OF PROCESSING SCALE ON THE PRESSURE-DROP OF COMPRESSIBLE GEL SUPPORTS IN LIQUID-CHROMATOGRAPHIC COLUMNS

Experimental data are given for the solid pressure distributions in li quid chromatographic columns for two commercially available agarose-ba sed compressible gel supports. The data show that for a given liquid v elocity the pressure drop increases exponentially with height from the top surface. However, beyond a threshold liquid velocity, flow instab ility develops rapidly and the pressure drop rises sharply as the gel matrix compresses under the applied vertical pressures. The threshold liquid velocity at the point of criticality is examined in the light o f the experimental data and the numerical simulations based on a one d imensional elemental slice force balance of the gel mass. The result o f this analysis shows that matrix rigidity, column diameter and bed he ight significantly affect the point of criticality.