Accurate detection of organophosphorus pesticides based on covalent organic framework nanofiber with a turn-on strategy

In this work, an electroactive COF Tab-Dva nanofiber with abundant vinyl group was prepared and used to fabricate electrochemical biosensors for O,O-dimethyl-O-2,2-dichlorovinylphosphate (DDVP), an organophosphorus pesticide. The COF Tab-Dva nanofiber with large surface area and plentiful vinyl group facilitate the immobilization of AChE and enrich the thiocholine. Thanks to that, a low potential turn-on DDVP electrochemical sensor with [Ru(bpy) 3 ] 2+ as the detection probe was proposed for the first time. Meanwhile, a ratiometric DDVP sensor with the oxidation peak of thiocholine as response signal, the oxidation peak of COF Tab-Dva as reference signal, and a low potential turn-off electrochemical sensor with oxidation peak of [Fe(CN) 6 ] 3− as response signal were proposed as the contrast experiment. The performances of these sensors were investigated and compared in detail. The results reveal the low potential turn-on DDVP sensor with [Ru(bpy) 3 ] 2+ as the detection probe can not only effectively improve the selectivity, but also avoid the influence of large background current, providing a new and effective method for pesticide detection. • COF Tab-Dva with abundant vinyl was used to load AChE and enrich thiocholine. • Three DDVP electrochemical sensors were proposed and compared. • Turn on strategy for detection of organophosphorus pesticides has been proposed. • DDVP electrochemical sensors with satisfactory selectivity has been proposed.