The isosteric heat of adsorption of some n-alkanes (n-C-5 to n-C-8) on some adsorbents (activated alumina, natural zeolite(clinoptilolite) and 13X molecular sieve) were evaluated by inverse gas chromatography using the temperature dependence of adsorption. The isosteric heat of adsorption of the probes on alumina and clinoptilolite were determined in the finite concentration region, and those on 13X were determined in the infinite dilution region. It was found that the adsorption isotherms for alumina and clinoptilolite conform with the Langmuir. equation, and the isosteric heats of adsorption increase linearly with increasing carbon number of the probes for alumina and 13X.