Molecular Shape Selectivity for Polycyclic Aromatic Compounds on a Poly(benzoguanamine-co-melamine-co-formaldehyde) Stationary Phase in Reversed-Phase Liquid Chromatography

A novel spherical polymeric material has been introduced as a stationary phase in liquid chromatography (LC). Poly(benzoguanamine-co-melamine-co-formaldehyde) (BMF) was packed into a stainless-steel tube having 4.6 mm i.d., 150 mm length, as a particulate separation medium in LC. The retention behavior for polycyclic aromatic compounds (PACs) on the BMF phase was evaluated in reversed-phase LC and the trend was compared with that on a commercially-available octadecylsilica (ODS) phase. The BMF phase showed a unique molecular shape selectivity for PACs. It was clearly different from that on typical ODS phases. The BMF stationary phase more strongly retained "rod-like" molecules such as naphthacene than "square-like" molecules with a relatively large molecular weight. From the results, it was considered that the phenyl groups as stationary phase ligands were exposed on the surface of BMF particles, and these phenyl functionalities were apart from each other. Therefore, the BMF phase strongly retained "rod-like" analyte molecules that can simultaneously interact with more than one phenyl groups of the stationary phase.