The adsorption of Naproxen enantiomers on the chiral stationary phase (R,RR,R)-Whelk-O1 under reversed-phase conditions: The effect of mobile phase composition

The adsorption of the Naproxen enantiomers on the Whelk-O1 chiral stationary phase from acidic (0.01 M CH3COOH) methanol–water solutions was studied using the frontal analysis method and band profile calculations. The adsorption model that best accounted for these data is one assuming the coexistence of three types of adsorption sites, two of them being enantioselective, associated with the chiral selectors, the third type being the nonselective type of sites associated with residual surface silanol groups. The adsorption equilibrium is influenced by secondary processes that result in variations of the model parameters with the mobile phase composition. Several qualitative correlations between the model parameters and the methanol–water ratio were observed and are discussed.