A novel electrochemical sensor based on molecularly imprinted polymer modified hollow N, S-Mo2C/C spheres for highly sensitive and selective carbendazim determination.

A novel electrochemical sensor based on nitrogen and sulfur doped hollow Mo2C/C spheres (N, S-Mo2C) and molecularly imprinted polymer (MIP) was proposed for carbendazim (CBD) determination. The N, S-Mo2C were prepared by first nitrogen and sulfur doping via one-pot method and subsequent carbonization at high temperature. A film of MIP was then fabricated in situ on the N, S-Mo2C surface by electropolymerization, with CBD acting as template molecule and o-phenylenediamine as functional monomer. The N, S-Mo2C were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and electrochemical behaviors of CBD on differently modified electrodes were explored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, a calibration curve of current shift versus the logarithm of CBD concentration was obtained in the range of 1×10-12 ∼ 8×10-9 M with a detection limit of 6.7×10-13 M (S/N=3). Moreover, the proposed sensor exhibited favorable stability and selectivity, and was applied to analyze pesticide residues in fruits and vegetables with decent accuracy.