Preparation of 4‐butylaniline‐bonded silica gel for the solid‐phase extraction of flavone glycosides

To extract flavone glycosides efficiently, a new extraction material based on 4‐butylaniline‐bonded silica gel was prepared using a two‐step grafting method including a ring‐opening reaction and synchronous hydrolysis. Preparation of the silica‐based material was easily achieved under mild conditions, and the material was characterized by Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy. The material was used in solid‐phase extraction, and the extraction can be performed in neutral conditions without regard to ionic strength. Selectivity tests of 14 compounds on the extraction cartridge showed that the material has a high affinity to flavone glycosides in contrast to octadecyl silica, and the extraction yields for four flavone glycosides were found to be >93%. Selectivity tests further reveal that the adsorption on its surface is likely attributed to multiple interactions, including hydrophobic interactions, π–π interactions, and hydrogen bonding. To explore the applicability of 4‐butylaniline‐bonded silica gel, naringin and hesperidin from Simotang oral liquid were extracted, and the extraction yields were >90%, which is distinguished from <28% on octadecyl silica cartridge.