STUDIES IN CHROMATOGRAPHIC TRANSPORT: III. CHROMATHERMOGRAPHY

Abstract

A compilation is given of the many Soviet publications on chromathermography (regular displacement chromatography plus a moving thermal gradient). However, the Soviet workers have failed to describe adequately the transport of adsorbates having Langmuir isotherms. The author corrects this situation with a simple but accurate theoretical treatment. It was found (in contrast to isothermal chromatography) that the relative velocity of transport in the trailing edge of a band obeyed the equation[Formula: see text]The characteristic temperature and/or spread of an adsorbate band depend on (1) the temperature distribution within the gradient; (2) the relative velocity of the gradient; (3) the adsorption isotherm as a function of temperature; (4) the amount of adsorbate; (5) the nature of the carrier solvent; (6) the presence, the amounts, and the isotherms of other adsorbates.Whereas most forms of chromatography dissipate the adsorbate and reduce its concentration, chromathermography provides a mechanism for concentrating the adsorbate to a level that can be above the concentration at which it is injected into the column.