CHARACTERIZATION OF SOME SILICA-BASED REVERSED-PHASE LIQUID-CHROMATOGRAPHIC COLUMNS BASED ON LINEAR SOLVATION ENERGY RELATIONSHIPS

The characterization of six silica-based reversed-phase liquid chromat ographic columns was attempted by calculating characteristic interacti on constants for the stationary phases based on linear solvation energ y relationships. Four interaction properties of the stationary phase, m (the cavity formation/dispersive interaction strength), s (dipolarit y/polarizability), b (hydrogen bond donating acidity) and a (hydrogen bond accepting basicity), are readily determined by multiple regressio n analyses of logarithmic capacity factors (k') for a set of test solu tes measured on it in an aqueous mobile phase of a given organic conte nt versus the solute properties represented by the Van der Waals molar volume, Kamlet-Taft dipolarity/polarizability, pi, hydrogen bond acc epting basicity, beta, and hydrogen bond donating acidity, alpha. The magnitudes of the four constants vary with the type of bonded ligand a nd with brand in the case of stationary phases having the same ligand, while they generally decrease in the order m > b > a > s, regardless of the type of the organic modifier in the mobile phase for all six co lumns. Although the four interaction strength constants are not as gen eral as the widely used Rohrschneider and McReynolds constants for GLC stationary phases, it is believed that they will be useful in choosin g the best column for a given separation among a number of nominally e quivalent columns and columns with different bonded functionality.