Nucleotide coordinated polymer nanoparticle-based hydrogel sensing platform for visual detection of organophosphorus and carbamate pesticides

Rapid and reliable on-site detection of pesticide residues is crucial for safeguarding public health and environmental safety. This study developed a rapid detection method for pesticide residues based on iron-guanosine monophosphate coordination polymer nanoparticles (Fe-GMP CPNs). Fe-GMP CPNs possess peroxidase-like activity and can catalyze the H 2 O 2 -3,3′,5,5′-tetramethylbenzidine (TMB) colorimetric reaction. By integrating acetylcholinesterase (AChE), a colorimetric detection platform was constructed: in the absence of pesticides, AChE hydrolyzes acetylthiocholine (ATCh) to produce thiocholine (TCh), TCh inhibits the color development; in the presence of pesticides, the inactivation of AChE restores the blue color, enabling the visual detection of organophosphorus and carbamate pesticides. To further achieve on-site analysis, the detection reagents were encapsulated in agarose hydrogels and combined with smartphone colorimetric technology to realize on-site rapid detection of carbaryl and trichlorfon. This research promotes the development of nanozyme sensing technology and provides a new approach for the next generation of food safety detection.