Electrochemical sensor based on molecularly imprinted composite membrane of poly(o-aminothiophenol) with gold nanoparticles for sensitive determination of herbicide simazine in environmental samples

•A novel electrochemical sensor based on molecularly imprinted polymer membranes (MIPM) as biomimetic molecular recognition element had been established.•The ATP@AuNPs effectively prevent from AuNPs aggregation via forming a rigid 3D framework structure, enhance electron transport and increase the immobilized amounts of template per unit surface area.•Ultrasensitive, specific quantification of herbicide simazine had been achieved.•The proposed sensor provided a simple and reliable technique for SMZ detection in environmental samples and a notion to perfect the MIP-based sensor for trace detection.

A novel electrochemical sensor based on molecularly imprinted polymer membranes (MIPM) as biomimetic molecular recognition element involved in o-aminothiophenol functionalized Au nanoparticles (ATP@AuNPs) modified gold electrode was constructed for sensitive and selective detection of herbicide simazine (SMZ). The nano-scaled MIPM, with high specific surface area, was prepared by self-assembly of o-aminothiophenol (ATP) and electrodeposition of ATP@AuNPs in the presence of template SMZ. Cathodic current of SMZ was measured by cyclic voltammetry and the results exhibited that the proposed sensor possess a high electrocatalytic activity at a negative potential and a fast rebinding dynamics towards the reduction of SMZ in 0.01 M H2SO4 solution (pH 1.7). Linear dependency of peak current on SMZ concentrations was observed from 0.03 to 140 μM and detection limit was estimated to be 0.013 μM (3S/N). The enhancement of sensitivity was attributed to the presence of gold nanoparticles (AuNPs) which decreased the electron-transfer impedance and increased imprinting sites, lead to the superior enrichment effect of the trace amount of SMZ in aqueous solvent. The developed SMZ imprinted sensor exhibited excellent long-term stability and acceptable repeatability. In addition, the proposed method was successfully applied to measure SMZ in several real samples with the spiked recoveries changing from 91.4% to 96.8%, showing a promising potential in practical application.