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Preparation of polydopamine-coated, graphene oxide/Fe3 O4 - imprinted nanoparticles for selective removal of sulfonylurea herbicides in cereals.

BACKGROUND
Sulfonylureas are potentially toxic broad-spectrum herbicides. They pose a persistent threat to food safety and the environment. Therefore, it is important to develop a rapid and efficient pretreatment and detection method to prevent their harmful effects on human health.


RESULTS
In the present work, a novel and highly selective absorbent for chlorosulfuron (CS) detection was prepared by the simple self-polymerization of dopamine on the surface of magnetic graphene oxide using a CS template. The resultant imprinted nanoparticles (MGO@PDA-MIPs) were characterized by transmission electron microscopy, X-ray diffraction, vibrating-sample magnetometry, thermogravimetric analysis, and nitrogen adsorption-desorption. The adsorption experiments demonstrated that the MGO@PDA-MIPs have excellent selectivity with regard to CS, with a high imprinting factor of 3.41 compared with a non-imprinted polymer. The nanoparticles rapidly achieve adsorption equilibrium and efficient desorption because there are numerous binding sites on the thin polydopamine imprinting layer. Under optimized conditions, the MGO@PDA-MIPs can be used to detect sulfonylurea residues in cereal samples by magnetic solid phase extraction coupled with high performance liquid chromatography (HPLC). The nanoparticles have a satisfactory recovery rate (80.65-101.01%) with a relative standard deviation (RSD) of less than 7.15%, and a limit of detection with regard to CS of 1.61 μg kg-1 (S/N = 3). They can also be re-used at least seven times.


CONCLUSION
The MGO@PDA-MIPs have outstanding recognition performance, and can be prepared by a facile, single-step, and environmentally friendly process. Therefore, they have great potential for the recognition and separation of trace sulfonylurea herbicides in complex matrices. This article is protected by copyright. All rights reserved.