Preparation and retention characteristics of different phenyl phases for reversed-phase liquid chromatography

Summary Three different phenyl phases were prepared. The amount of organic moiety bound on silica support was determined from thermogravimetric curves of the modified silica gel. The specific surface areas of gels were obtained from nitrogen sorption measurement at –196°C. The effect on separation and selectivity of the different bonded-phenyl functional groups was studied. The selectivity of the phenyl-bonded silica gels was examined and compared with octadecyl (ODS) silica in liquid chromatography. Corresponding to the high surface concentration of functional groups, the capacity factors of solutes, normalized to unit surface area of the adsorbent, k/S_BET were found to decrease in the sequence phenylmethyl>diphenyl>triphenyl. Polar solutes are retained in greater extent on the phenyl phases than on the ODS phase.