Nanosensing of Pesticides by Zinc Oxide Quantum Dot: An Optical and Electrochemical Approach for the Detection of Pesticides in Water

Present study reveals the low concentrations (∼4 ppm) of pesticide sensing vis-a-vis degradation of pesticides with the help of nontoxic zinc oxide quantum dots (QD). In our study, we have taken four different pesticides viz., aldrin, tetradifon, glyphosate, and atrazine, which are widely used in agriculture and have structural dissimilarities/diversity. By using optical sensing techniques such as steady state and time-resolved fluorescence, we have analyzed the detailed exciton dynamics of QD in the presence of different pesticides. It has been found that the pesticide containing good leaving groups (−Cl) can interact with QD promptly and has high binding affinity (∼107 M–1). The different binding signatures of QD with different pesticides enable us to differentiate between the pesticides. Time resolved fluorescence spectroscopy provides significant variance (∼150–300 ns) for different pesticides. Furthermore, a large variation (105 Ω to 7 × 104 Ω) in the resistance of QD in the presence of different pes...