Fabrication of electrochemical sensor based on molecularly imprinted polymers for monitoring chlorpyrifos in real samples

Abstract

Chlorpyrifos (CPF) is an organophosphate pesticide that has been used for decades to enhance crop yield but its persistent usage has led to dreadful health issues in humans as well as other species. In the current work, an electrochemical sensor has been fabricated with immobilized molecularly imprinted polymers (MIPs) on a glassy carbon electrode to detect CPF. MIPs were bulk polymerized with a functional monomer itaconic acid. MIPs were characterized by Fourier transform infrared spectroscopy, scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy. The execution of the developed electrochemical sensor was scrutinized with differential pulse voltammetry (DPV). Various parameters like the pH of the electrolyte, the concentration and volume of MIPs (after elution), and the adsorption time were optimized for the analysis of the analyte (CPF) with the fabricated sensor. Under optimal conditions, the peak current of different CPF concentrations was examined by DPV method. The peak current was in linear proportionality with CPF (2.8 × 10⁻¹⁴ to 2.8 × 10⁻⁵ mol l⁻¹) with a low detection limit of 1.912 × 10⁻¹⁴ mol l⁻¹. The developed electrochemical sensor detected CPF in real samples with excellent results and a recovery percentage ranging from 100 to 106% (relative standard deviation, RSD < 5%). Also, the sensor exhibited good reproducibility, stability and selectivity. Therefore, the developed electrochemical sensor holds great potential for the monitoring of CPF in fruits and vegetables.