Li_2026_Food.Chem_515_149267

Dichlorvos (DDVP) misuse in agriculture threatens food safety, making its monitoring crucial. Herein, a ratiometric fluorescent sensor was developed using a UiO-66-NH@MnO composite for visual DDVP detection. The MnO nanosheets (MnO NSs) quenched the blue fluorescence (430 nm) of metal-organic frameworks (MOFs) UiO-66-NH but oxidized o-phenylenediamine to yield yellow-emitting 2,3-diaminophenazine (DAP) at 565 nm. Acetylcholinesterase (AChE) catalyzed the generation of thiocholine, which decomposed MnO NSs and restored the blue fluorescence. In contrast, the presence of DDVP inhibited AChE activity, thereby preserving MnO NSs and maintaining the yellow fluorescence. A ratiometric fluorescence method and a smartphone-assisted fluorescence visualization method for DDVP were developed based on the sensor, achieving detection limits of 0.169 ng/mL and 0.756 ng/mL, respectively. Both methods successfully detected DDVP residues in tea and honeysuckle, showing satisfactory recovery and consistency with UPLC-MS/MS results. Overall, this study offers promising prospects for the routine monitoring of DDVP residues in food safety.