Molecularly Imprinted Electrochemical Sensor Based on the Self-Assembly of Cage-like Gold Nanoparticles and Amino-Functionalized rGO for the Detection of Diuron in Cotton Defoliant

Abstract

Diuron (DU) is a kind of cotton defoliant with high toxicity and strong persistence that poses a serious environmental threat. DU has electroactive inertness and oxidation resistance, and there are only a few types of recognition elements, making its sensitive and specific detection critical. Herein, a novel molecularly imprinted polymer-based electrochemical (MIP-EC) sensor was developed by combing gold nanocages (AuNCs) with hollow-interior and porous walls with amino-functionalized reduced graphene oxide nanosheets (NH₂-rGO) with a large surface area and excellent conductivity. Then, DU-MIP was directly grown on the modified electrode by electropolymerization, while it displayed a high imprinted factor (6.91) and high reusability (at least 5 times). Significantly, the NH₂-rGO/AuNC nanocomposite could also enhance the recognition efficiency of DU-MIP, improving the analytical performances of the MIP-EC sensor, with the detection limit down to 4.3 ng/mL. In addition, this sensor exhibited high selectivity and rapid elution/recombination, and a simple construction process was utilized to detect DU in cotton and soil.