An inverse gas chromatographic (IGC) study of the sorption properties of poly(ethylene glycol) modified with tosylate (PEG-TOS) was presented. PEG-TOS was synthesized via the tosylation of the corresponding poly(ethylene glycol) (PEG) with p-toluenesulfonyl chloride in the basic medium. The synthesized PEG-Tos was characterized by FTIR-ATR and (HNMR)-H-1 techniques. The retention diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane, dichloromethane, chloroform, acetone, tetrahydrofuran, ethyl acetate, and ethanol on the PEG and PEG-Tos were plotted at temperatures in K between 303 and 373 by inverse gas chromatography technique. The dispersive component of the surface-free energy, gamma(D)(S), of studied adsorbent surface was estimated using retention times of different nonpolar organics in the infinite dilution region. Thermodynamic parameters of adsorption (free energy, Delta G(A)(S), enthalpy, Delta H-A(S), and entropy, Delta S-A(S)), dispersive components of the surface energies, gamma(D)(S), and the acid, K-A, and base, K-D, constants for the PEG and PEG-Tos were calculated and the results were discussed.