Highly Sensitive Detection of Carbendazim and Its Electrochemical Oxidation Mechanism at a Nanohybrid Sensor

Sensitive and rapid detection of pesticides in food has become an important and crucial research area due to the extensive use of agriculture residues and stringent environmental protection acts. In present work, an electrochemical nanohybrid sensor was facilely developed based on carboxymethyl cellulose (CMC) fuctionalized carbon nanotubes (CNTs). The sensor shows high sensitivity, excellent stability and good anti-interference capability in the detection of carbendazim (MBC) by differential pulse voltammetry method. Under optimized conditions, it exhibits a wide linearity of 0.03 μmol·L−1 – 10 μmol·L−1 with a low detection limit of 0.015 μmol·L−1. In real samples analyses for peer and kiwifruit, the proposed sensor shows good recoveries which are comparable with that of the conventional HPLC method. In addition, the oxidation mechanism of MBC at the nanohybrid sensor was studied using voltammetric methods and validated according to the density functional theory (DFT) calculation. The results reveal that the oxidation of carbendazim is a typical adsorption-controlled electrochemical oxidation process proceeding with four protons and four electrons. The proposed nanohybrid sensor is a promising alternative to the currently used methods for carbendazim detection and our results provide a new insight in MBC electrochemical oxidation mechanism.