Gas-liquid chromatography is used to study the thermodynamic interactions between polystyrene and n-alkanes (C-6-C-10). Polystyrene is used as a stationary phase with n-alkanes as the probe molecules. Retention times and specific retention volumes are measured over the temperature interval of 60 to 170 degreesC. Partial molar free energy of mixing, polymer-solvent interaction parameter, glass-transition temperature, and solubility parameter of polystyrene at infinite dilution are calculated. Experimental results are discussed in terms of the theoretical calculations and size of the probe molecules.