Gold nanoparticle-mediated molecularly imprinted electrochemical sensor MIP/AuNPs/GCE for highly sensitive and selective detection of neutral phosmet residues in fruits and vegetables

Abstract

A novel electrochemical sensor MIP/AuNPs/GCE was developed by depositing gold nanoparticles and electropolymerizing molecularly imprinted film on the surface of glassy carbon electrode (GCE) for highly sensitive detection of neutral phosmet residues in fruits and vegetables. Scanning electron microscopy, energy dispersive spectroscopy, atomic force microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the imprinted sensor. The results showed that the imprinted film on GCE was evenly prepared with better specific recognition of phosmet on MIP/AuNPs/GCE than that on bare GCE. Several parameters including deposition time, functional monomer and its molar ratio, scanning cycles, and elution time were optimized in detail. The linear range of the MIP/AuNPs/GCE prepared in this work was 0.020–4.0 nmol/L with limit of detection of 0.010 nmol/L, which was much lower than MIP/GCE (0.17 nmol/L). The identification mechanism of MIP/AuNPs/GCE for phosmet was also confirmed as adsorption-diffusion model with effective surface area increasing after mediated by AuNPs. Selectivity, reproducibility and repeatability of the MIP/AuNPs/GCE were acceptable. The recovery of applying the sensor to detect PM in real samples ranged from 91.40 % to 107.3 %, which agreed well with those of HPLC. The method of developing MIP/AuNPs/GCE sensor herein could be extended to detecting other neutral pesticide residues in food and environment.