The inverse gas chromatography technique at infinite dilution was used to calculate the acidic and basic constants of four carbon fibers. We determined the specific interactions between them and model organic molecules and proved the amphoteric feature of such caron fibers. We proposed a new method by adding of a third parameter K that can reflect the amphoteric feature of a solid. The relationship proposed is: (-Delta H-sp) = K-A.DN + K-D.AN - K.AN.DN. We proved that our model gives the best results relative to those obtained by the classic equation.