Adsorbents were prepared, based on silica gel modified with phthalocyanine and copper and nickel phthalocyanates (H~Pc, CuPc, NiPc) by adsorption of phthalocyanine from a solution in concentrated sulphuric acid. Adsorbents based on graphitized thermal carbon black (Carbochroms) were also been prepared. Carbochrom B was modified with copper phthalocyanate using adsorption from l-bromonaphthalene solution and with sodium salts of the sulphonic acids of copper phthalocyanate [CuPc(SO,Na)d] using adsorption from aqueous solutions. Efficient adsorbents, showing high selectivity, were thus obtained. The modified adsorbents were applied to gas-solid chromatographic measurements using packed and micropacked columns. The adsorbates used were n-pentane, n-hexane, n-heptane, cyclohexane, 1-hexene, benzene, ðyl ether, propanol, acetone and nitrobenzene. The advantages of the prepared materials in analytical applications include shorter analysis times, improvement in peak symmetry and separation and high temperature stability. The differential heats of adsorption and the contributions of specific interactions of selected adsorbates were calculated from the chromatographic data and are discussed. The experimental values of the differential heats of adsorption were compared with published data.