High retentivity and selectivity for polycyclic aromatic hydrocarbons with poly(4-vinylpyridine)-grafted silica in normal-phase high-performance liquid chromatography

In this study, we introduce an attractive stationary phase, poly(4-vinylpyridine)-grafted silica (VP_n) for normal-phase high-performance liquid chromatography. The retention behavior of polycyclic aromatic hydrocarbons (PAHs) was investigated with VP_n column under n-hexane/2-propanol mixture as mobile phase. Conventional octadecylated silica, aminopropyl-bonded silica, bare silica and poly(styrene)-grafted silica columns were used as reference columns. Extremely high retention factors were observed for PAHs but not for alkylbenzenes and distinct higher selectivity towards PAHs was observed for the detailed molecular shape such as planarity and aspect ratio. The reason for these results seems to be a multiple interaction effect including an inductive interaction between the pyridyl and aromatic rings.