Chromatographic evaluation of alkylphosphonic acid-modified ceria-zirconiain reversed-phase HPLC

Porous ceria-zirconia sperules were surface modified with alkylphosphonic a cid to create reversed phase material. The chromatographic properties of th e ceria-zirconia-based stationary phase were evaluated in detail with neutr al, basic, and acidic compounds as probes, over a wide range of mobile phas e composition and pH. Polycyclic aromatic hydrocarbons (PAHs) were well sep arated and their elution order were in accordance with those reported on th e silica-based reversed-phase column. Typical reversed-phase chromatographic behavior was also observed with basi c solutes at pH10.0, whereas dual mode retention mechanism was adopted to e lucidate retention characteristics of some of the basic solutes at pH4.0. A cidic compounds exhibited strong interaction with the alkylphosphonic acid modified ceria-zirconia (PA-CeO2-ZrO2) with methanol-water mixture as mobil e phases, but these interaction were reduced to different extents in the pr esence of competing agents, such as acetate, sulfate, and oxalate. o-hydrox ybenzoic acid irreversibly adsorbed on the PA-CeO2-ZrO2 stationary phase, e ven in the presence of oxalate, which may be explained by the formation of chelate ring.