Determination of the volumes of void zones in packed chromatographic columns

Abstract

In gas chromatography there is a pause in flow when sorbable material enters the packing and is absorbed by the stationary phase. There is a complementary surge in flow when the band of sorbed material leaves the packing. When a band passes a void zone, these effects combine to produce a doublet relative to the base-line on a recording of flow-rate against time. Such fluctuations can be measured by using a sensitive differential capillary flow meter. A theory is developed that enables the volumes of void zones in packed chromatographic columns to be found by measuring fluctuations in flow-rate observed when bands of sorbable material pass through the void zones. The theory is confirmed by experiment. The volume of a 0.06-cm 3 void zone was estimated to within about 3%.