Preparation and characterization of modified 3-aminopropylsilyl silica phases with 1,8-naphthalic anhydrides in HPLC

Modified 3-aminopropylsilyl silica stationary phases with 1,8-naphthalic anhydrides 3-(1,8-naphthalimido)propyl (NAIP), 3-(4-amino-1,8-naphthalimido)propyl (4A-NAIP), 3-(3-nitro-1,8-naphthalimido)propyl (3N-NAIP), and 3-(4-nitro-1,8-naphthalimido)propyl modified silyl silica gel (4N-NAIP)] are prepared in a single reaction. Chromatographic properties of these phases are characterized using various solutes including monosubstituted benzenes, alkyl benzenes, and polycyclic aromatic hydrocarbons (PAHs) in high-performance liquid chromatography. Even though the retention in these NAIPs is mainly based on the reversed-phase mode, 3N- and 4N-NAIP show a remarkable recognition toward aromatic hydrocarbons, which is attributed to their strong pi-pi interaction. Furthermore, the recognition ability is according to the molecular planarity and non-linearity of PAHs. Subsequently, 3N- and 4N-NAIP has a distinct selectivity from octadecyl silica and, therefore, will be a valuable alternative for a separation or a solid-phase extraction of aromatic compounds.