Practical Examination of a Nonporous Silica Stationary Phase for Reversed-Phase Fast LC Applications

The performance of a nonporous silica reversed-phase high-performance liquid chromatographic stationary phase (1.5 μm) is examined and contrasted with that of a conventional stationary phase. The conventional column exhibits classic van Deemter behavior with respect to the impact of flow rate on efficiency, but the “fast” liquid chromatographic (LC) column’s efficiency is not as strongly affected by flow rate because of its lessened contributions of longitudinal diffusion and stagnant mobile phase mass transfer effects and greater sensitivity to system void volume effects. Both columns exhibit roughly equivalent efficiencies on a per meter basis; however, the efficiency of the fast LC column was more strongly influenced by solute capacity factor. Retention by the fast LC column is more strongly influenced by mobile phase composition. In general, the fast LC column produces multispecies separations more rapidly with a weaker mobile phase than does the conventional column, which results in considerable reduction in solvent usage without a significant loss of efficiency. The performance of the fast LC column is strongly influenced by the system configuration, especially with respect to total system void volume.