Selectivity of amino-, cyano- and diol-bonded silica in reversed-phase liquid chromatography

Amino-, cyano- and diol-bonded silica stationary phases were characterized by estimating their characteristic interaction constants in reversed-phase liquid chromatography (RPLC) based on linear solvation energy relationships. Five characteristic interaction constants of the stationary phases, the hydrophobicity ( v), polarizability ( r), dipolarity ( s), hydrogen bond (HB) acceptor basicity ( a) and HB donor acidity strength ( b) were determined by multiple regression analyses of logarithmic retention factors ( k) for a set of test solutes measured on them in 10% (v/v) methanol–water vs. the solute properties represented by characteristic molecular volume ( V x ), excess polarization ( R 2), dipolarity/polarizability ( π ∗ ), HB donor acidity ( α) and HB acceptor basicity ( β). Magnitudes of the five constants for the phases in RPLC were compared with those in normal-phase LC to see the differences in chromatographic selectivity in the two LC modes.