An electrochemical sensing strategy for organophosphorus pesticides based on dual-enzyme synergistic catalysis of plant esterase and diatomic FeCo-NC nanozyme.

This study presents a novel electrochemical strategy for detecting organophosphorus pesticides based on the synergistic catalytic of red kidney bean esterase (RKBE) and iron-cobalt dual-atom catalyst embedded in N-doped carbon carrier (FeCo-NC). RKBE was extracted from the widely cultivated British red kidney beans (Phaseolus vulgaris L.). FeCo-NC exhibited excellent electrocatalytic and peroxidase-like activity, catalyzing o-phenylenediamine oxidation to produce electroactive 2,3-diaminophenazine, which served as signal probe generating a sensitive cathodic current. Notably, RKBE product 1-naphthol inhibited FeCo-NC activity, while organophosphorus pesticides counteracted this inhibition by suppressing RKBE activity, restoring the electrochemical signal of 2,3-diaminophenazine. Leveraging this signal-regulation mechanism, a dichlorvos sensor was developed, with wide linear range (50-50,000 pM), low detection limit (14 pM), and excellent real-sample recovery (93.33%-107.08%), demonstrating practical application potential. This study provides an affordable and easy-to-operate approach for large-scale on-site monitoring of organophosphorus pesticide residues in foods.