Inverse Gas Chromatography (IGC), in contrast to analytical chromatography, consists on adsorption of a known solute on an adsorbent whose properties are to be determined. The shape and positions of the peaks supply information about the nature and reactivity of the solid surface. If different probe molecules are used (i.e. polar and apolar molecules, molecules with acid/base properties), it is possible to study the specificity of these interactions. Therefore, IGC can be used both as a tool for both characterizing the adsorption of a given compound on a given solid or for studying the nature (in terms of acid-base properties, polar or apolar interactions, etc.) of the active sites of a certain catalyst.
IntroductionSorption measurements are a useful method in the characterization of solid materials. From these data, it is possible to obtain information about the capacity of adsorption, but also thermodynamic properties-enthalpies of adsorption, surface energy-as well as kinetic information, such as diffusion rates. Sorption measurements can be obtained either by static or dynamic methods. Static methods carried out the adsorption measurements under vacuum, after a pre-treatment at high temperature in order to clean the material surface. Dynamic methods use a flowing gas device. Inverse gas chromatography (IGC) is a dynamic method. In comparison to static adsorption systems, dynamic sorption techniques show shorter measurement time, and a wider range of experimental possibilities.In contrast to analytical chromatography, the stationary phase is the sample under investigation, and the mobile phase acts as probe molecule. Thus, the roles of the