Resumen de Gas Chromatographic Measurement of Void Volume and Mobile Phase Volume:: Illustration of the Concepts of Excess and Total Adsorption
In gas-solid systems two types of adsorption, namely excess and total, can be envisioned depending on how the volume of the mobile phase containing free adsorbent molecules is measured. The distinction between excess and total adsorption arises from the assignment for the location of the Gibbs dividing surface. The standard volumetric and gravimetric techniques for measuring adsorption cannot differentiate the two types of adsorption, and there is no classical method available for determining the location of the Gibbs dividing surface. Chromatographic methods including tracer pulse techniques can, however, be employed to measure both excess and total adsorption. The concepts of void volume and mobile phase volume employed in gas chromatography can be used to distinguish the two different types of adsorption.
