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.