CHARACTERIZATION OF A SUPERCRITICAL FLUID CHROMATOGRAPHIC RETENTION PROCESS WITH A LARGE PRESSURE-DROP BY THE TEMPORAL AVERAGE DENSITY

The characterization of supercritical fluid chromatographic retention by different forms of the average density, viz., the temporal average density, the spatial average density and the arithmetic average density, is investigated in a system with appreciable pressure drop along the column. The logarithm of the capacity factor, when described in terms of the temporal average density, is independent of the pressure drop. Hence, supercritical fluid chromatographic retention processes can be characterized and represented by a hypothetical zero-pressure-drop system at a density equal to the temporal average density of the real system.