Surface energies of hydrophobic interaction chromatography media by inverse liquid chromatography.

Hydrophobicity of hydrophobic interaction chromatography media is currently ranked according to retention of reference proteins. A new method, suitable for porous media, is presented here to determine the surface energy and its Lifshitz-van-der-Waals, Lewis acid and Lewis base contributions. The theory of van Oss has been adapted for data obtained by inverse liquid chromatography. Furthermore, this method is characterized by the independence of the determination of the phase ratio. The retention of probes with different molecular properties was used to calculate the surface energy and the Lifshitz-van-der-Waals as well as Lewis acid and Lewis base contributions to the surface energy. The media with polymethacrylate backbone had a higher surface energy (γ ≈ 200 mJ/m(2)) and Lifshitz-van-der-Waals contribution (γ(LW) ≈ 140 mJ/m(2)) than the agarose-based media (γ ≈ 90-180 mJ/m(2) and γ(LW) ≈ 50-160 mJ/m(2)).