Packing of preparative high-performance liquid chromatography columns by sedimentation

Based on the colloid chemistry of a suspension of ODS packing material, a new packing technique using particle sedimentation has been developed. With this approach, a slurry consisting of the packing and a deflocculating solvent is poured into the column, the bed was formed by sedimentation. The bed is then solidified by a flocculating solvent. Using acetone as the slurry solvent and methanol—water (1:1) as the solidification solvent, high-quality columns (150 mm × 21 mm I.D., 16-μm C18-silica packing) were successfully packed with reduced plate heights of 2.5–3.6 and typical A terms in the Knox plot below 1.0. The normalized sedimentation volume is introduced as a basis for the selection of sedimentation and solidification solvents. Various experimental factors, including slurry concentration, solidification flow-rate programming and temperature, are studied and discussed.