Universal solvent-adaptive fluorescent AZ NPs-ACh sensor for reliable visual detection of organophosphorus pesticides via AChE-H2O2 signaling

Organophosphorus pesticides (OPs) pose a serious threat to public health and food safety through irreversible inhibition of acetylcholinesterase (AChE) activity, so the development of a visual detection method suitable for complex matrices is urgent. In this work, a novel fluorescence sensor was constructed based on the coordination assembly of gold-silver nanoclusters (AuAg NCs) with zinc ions (Zn 2+ ), which exhibits a characteristic fluorescence peak at an excitation wavelength of 310 nm and an emission wavelength of 690 nm, and enables specific recognition and detection of hydrogen peroxide (H 2 O 2 ). The detection system utilizes OPs as inhibitors of AChE, enabling quantitative monitoring of OPs by detecting the concentration of H 2 O 2 generated through the synergistic catalysis of AChE and its cascade enzyme choline oxidase (ChOx). Notably, in practical analyses, the sensor demonstrates excellent fluorescence response characteristics across various solvents. Particularly in the complex matrix of traditional Chinese medicine (TCM) such as: Chenpi samples, the sensor achieves accurate quantitative analysis of OPs, exhibiting a linear relationship within the range of 1–200 ng/mL. Furthermore, the sensor can be integrated onto a paper-based carrier, enabling semi-quantitative analysis of pesticide residues at the field site using a portable UV lamp, demonstrating significant practical application potential.