Structural changes of human serum albumin immobilized on chromatographic supports: a high-performance liquid chromatography and Fourier-transform infrared spectroscopy study

Chiral stationary phases obtained by immobilization of HSA on [C8] and [C18] reversed-phases and on poly(1-vinylimidazole)-coated silica were tested to resolve dl-tryptophan, N-benzoyl-dl-phenylalanine, RS-oxazepam and RS-warfarin racemic mixtures. Parameters of enantioselectivity measured in HPLC are correlated to structural and solvation states for adsorbed HSA, evaluated by FTIR spectroscopy. HSA immobilized on [PVI]-anion-exchangers is highly selective. HSA molecules are not self-associated, only unfolded for a small hydrophobic helix. The HSA-coated reversed-phases have a lower selectivity. Unfolding is larger but the indole-benzodiazepine chiral site is preserved and remains accessible.