SYNTHESIS AND CHARACTERIZATION OF A MOLECULARLY IMPRINTED POLYMER FOR PRECONCENTRATION OF CLOTHIANIDIN IN ENVIRONMENTAL SAMPLES

摘要

A molecularly imprinted polymer for the selective solid-phase extraction of clothianidin was prepared using the analyte as a template, methacrylic acid and styrene as functional monomers, ethylene glycol dimethacrylate as the cross-linker, acetonitrile as a porogen, and 2,2-azobisisobutyronitrile as an initiator. The polymer was characterized by scanning electron microscopy and infrared spectroscopy. Adsorption measurements indicated that the molecularly imprinted polymers exhibited good recognition ability and fast dynamics toward clothianidin. Using this imprinted polymer as a sorbent, a new method of molecularly imprinted solid phase extraction coupled to high performance liquid chromatography for the determination of clothianidin residues was developed. The molecularly imprinted solid phase extraction procedure was optimized to purify and enrich clothianidin residues in river water, soil, tomatoes, grapes, and Chinese cabbage. The average recoveries of clothianidin spiked at 0.005 to 0.05 mg/L were 84.32 to 89.49% in river water with a relative standard deviation 2.22 to 4.79% (n=3). The average recoveries of clothianidin spiked at 0.05 to 0.5 mg/kg were 85.49 to 96.36% in soil, grapes, Chinese cabbage, and tomatoes, with a relative standard deviation of 2.40 to 6.02% (n=3). Overall, this study provides a sensitive and effective method for the accurate determination of clothianidin residues in environmental samples.