Features of the adsorption of Naproxen on the chiral stationary phase (S,S)-Whelk-O1 under reversed-phase conditions.

Using elution chromatography, we studied the adsorption mechanism of the Naproxen enantiomers on the chiral stationary phase (S,S)-Whelk-O1, from buffered methanol-water solutions. We propose an adsorption mechanism that assumes monolayer adsorption of the more retained enantiomer and the associative adsorption of the less retained one. The effects of the mobile phase composition on the adsorption of Naproxen are discussed. The combination of an elevated column temperature and of the use of an acidic mobile phase led to the degradation of the column and caused a major loss of its separation ability. The use of a moderately acidic mobile phase at temperature slightly above ambient did not produce rapid severe damages but, nevertheless, hampered the experiments and caused a slow gradual deterioration of the column.