STUDY OF RADIAL COMPRESSION HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC COLUMNS FOR PREPARATIVE CHROMATOGRAPHY

The operating characteristics and efficiency of a preparative-scale, radial compression chromatograph are studied. Two commercial C-18 silica packings are used, one irregular and one spherical and monodispersed. For each packing, the relationship between mobile phase flow-rate, column backpressure, and radial compression pressure is determined. A model is proposed to explain this relationship and determine the radial compression pressure needed to maintain the column effectively compressed at each operating flow-rate. The chromatographic efficiency of these columns is also determined. When an adequate radial compression level is used, the efficiency of the preparative-scale system is nearly the same as that of analytical-scale columns. Applying incremental levels of radial compression can also lead to a restoration of the efficiency of columns whose performance was degraded by operation at low radial compression pressures.