No abstract

The dynamic void volumes of several gas-solid chromatographic systems were measured with varying amounts of nitrogen, carbon dioxide, ethane, or propane adsorbed on silica gel at 77 K. The void volume and total amount of material adsorbed were measured simultaneously as a function of adsorbate pressure by tracer pulse chromatography. The void volume was determined from the measured retention time of a 123He probe. The dynamic (kinetic) void volume of a column decreased linearly with increasing amounts of adsorbed material due to the increasing volume of adsorbed, stationary phase. The observed decrease in the dynamic void volume per mole of adsorbed material gave a direct measure of the molar volume or density of the adsorbed species. Measured values of the