Surface area of reversed-phase HPLC columns

Six reversed-phase columns from different manufacturers were characterized in terms of adsorbent geometry (e.g., pore volume, surface area, column void volume, and interparticle volume). Measurement of the surface area of chemically modified silica-based adsorbents is discussed together with the methods for the determination of the amount of adsorbent in the column. The behavior of nearly ideal chromatographic systems was studied. Retention factors of alkylbenzenes in acetonitrile/water and methanol/water systems were compared with surface-specific retention factors. The distribution of conventional retention factor values for the same analyte among the six columns using identical chromatographic conditions exceeded 35%, while the relative standard deviation of surface-specific retention factors was on the level of 3%.