Column hardware in preparative liquid chromatography with axial flow

Scale-up of liquid chromatography (LC) for preparative work poses a number of problems. Problems concerning the column as the carrier of the stationary phase are discussed. Only axial column flow and LC with elution are considered (not radial flow, thick-layer, centrifugal techniques, etc.). The choice, design and technology of columns have mechanical aspects, but they are also dictated by the choice of stationary phase, by sample size requirements and by other chromatographic requirements. A distinction is made between laboratory-size and production-size instrumentation. The design, packing and use of laboratory-size preparative LC columns is not so very different from usual analytical LC practice. Larger-size instrumentation requires different approaches. A bewildering variety of larger-sized column designs is already commercially available. Dry-packing, slurry-packing, axial and radial packing or a combination of the two, chromatography with or without compression all are advocated. About 50 manufacturers of preparative LC columns were asked to provide their latest documentation on larger-scale systems. An analysis and survey of current commercial production-scale LC columns, based on the replies received, is presented.