Organophosphorus pesticides were easily remained in fruits and vegetables which would be harm to the environmental safety and human health. In recent years, due to the simple preparation process, fast response and high sensitivity, the electrochemical (bio)sensors have received increasing attention, which were extensively used as the sensing platform for the detection of OPPs. The mechanisms for the determination of OPPs mainly included redox of nitrophenyl OPPs, enzyme hydrolysis and inhibition, immunosensor, aptasensor. Nowadays, the mainly explored electrode material has focused on metal-organic frameworks, metal and metal derivatives, carbon materials (carbon nanotube, graphene, g-C₃N₄), MXene, etc. These nanomaterials played important roles in the electrochemical (bio)sensors, which included: (a) as an electrocatalyst to promote the redox reaction, (b) as a carrier to load the enzyme or aptamer, (c) as a recognizer to identify the targets. The nanomaterials-based electrochemical (bio)sensor was a rapid, cost-effective methods to detect OPPs with high sensitivity. Besides, this review compared the analytical performance of different nanomaterials-based electrochemical (bio)sensors, and also identified the key challenges in the future. It would provide new ideas and insights to the further development and application of electrochemical (bio)sensors and the detection of pesticides in real samples.

With the improvement of people's safety awareness, the requirement of pesticide detection is gradually increasing, and many new detection methods toward Organophosphorus pesticide (OPs) has been further developed and applied. Nanomaterials-based biosensors have played an important role in the trace detection of OPs. This article mainly introduces the detection principle of enzymes and aptamers as the identification element of biosensors. Various nanomaterials (i.e., metals and metal oxides, carbon nanotubes, graphene and graphene oxide, quantum dots, metal organic frameworks, molecular imprinted polymers, etc.) possess their unique properties and play different roles in the enzyme and aptamer-based biosensors toward OPs: (a) to produce the optical or electrochemical signal; (b) as a carrier to load the enzyme or aptamer; (c) to enhance the signal response. Besides, the intelligent portable devices provide the possibility to realize the onsite and real-time detection. The limitations of some nanomaterials and the future development are discussed. Finally, the future of enzyme and aptamer-based biosensors has prospected. Graphical Abstract Different types of biosensors for the detection of OPs

A simple, facile method was adopted to synthesize three-dimensional chitosan grafted graphene oxide aerogel modified silica (3D CS/GOA@Sil) as an eco-friendly, sustainable extraction material for the preconcentration of phenoxy acid herbicides. An amidation reaction realized the immobilization of CS and GO on the surface of silica, which was followed by a freeze-drying technique to yield the CS/GOA@Sil with 3D architecture structure. The successful synthesis and properties of 3D CS/GOA@Sil were characterized and confirmed by using scanning electron microscopy, infrared spectroscopy, BET adsorption–desorption analysis, and thermogravimetric analysis. The surface area of 3D CS/GOA@Sil was twice that of the individual GO@Sil. Besides, the adsorption and extraction times were also shorter due to the ordered porous structure and rapid mass transfer. Under the optimal conditions, coupled with a high-performance liquid chromatography-ultraviolet detector, this as-established method presented wide linearities with desirable correlation coefficients (≥0.9936) and low limits of detection (≤1.5 μg L⁻¹). Finally, it was applied in the analysis of phenoxy acid herbicides in vegetables, and satisfactory relative recoveries of 62.38–102.92% of spiked standard solutions with different concentrations were obtained.