Molecularly imprinted spin column extraction coupled with high-performance liquid chromatography for the selective and simple determination of trace nitrophenols in water samples.
In this study, we developed a simple and selective spin column extraction technology utilizing hydrophilic molecularly imprinted polymers as the sorbents for extracting nitrophenol pollutants in water samples (the East Lake, the Yangtze River, and wastewater). The whole procedure was achieved by centrifugation of the spin column, and multiple samples were simultaneously processed with a low volume of solvent and without evaporation. Under the optimized condition, recoveries of nitrophenol compounds on the spin column packed with hydrophilic molecularly imprinted polymers ranged from 87.3 to 92.9% and an excellent purification effect was obtained. Compared with activated carbon, multi-walled carbon nanotubes, LC-C18 sorbents, hydrophilic molecularly imprinted polymers exhibited a highly selective recognition ability for nitrophenol compounds and satisfactory sample extraction efficiency. Subsequently, the spin column extraction coupled with high-performance liquid chromatography was established, which was found to be linear in the range of 2-1000 ng/mL for 2,4-dinitropehnol and 2-nitrophenol, and 6-1000 ng/mL for 4-nitrophenol with correlation coefficients greater than 0.998. The detection limits ranged from 0.3-0.5 ng/mL. It is shown that the proposed method can be used for the determination of trace nitrophenol pollutants in complex samples, which is not only beneficial for water quality analysis but also for environmental risk assessment.