EFFECT OF THE CHAIN MOBILITY OF POLYMERIC REVERSED-PHASE STATIONARY PHASES ON POLYPEPTIDE RETENTION

The resolution of polypeptides in reversed-phase chromatography can be improved by inducing conformational changes in the solute. Protein unfolding can be achieved by an increased accessability of the hydrophobic stationary phase. We elucidated how far results from CP/MAS solid-state NMR relaxation measurements could be correlated with chromatographic data in terms of protein and peptide retention. The retentivity and denaturation potential of reversed stationary phases is controlled not only by their hydrophobicity but also by their ligand mobility and steric properties. As a consequence, we developed a simplified model for protein retention on stationary phases with different dynamic properties: We used an n-octadecyl phase (RP18), a poly(octadecyl methacrylate) phase (POMA), and a polybutadiene phase (PBD).