A highly sensitive electrochemical sensor based on surface molecularly imprinted polymers and graphene carbon nanotubes for highly selective detection of chlorpyrifos

Pesticide residues represent a serious challenge for environmental protection, food safety, and public health. Addressing this challenge, this study strategically developed an electrochemical sensor with molecularly imprinted polymers (MIPs) as the recognition element to accurately detect chlorpyrifos in environmental samples. In this study, we used vinyl-modified SiO2 as the matrix, methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the cross-linker, and azobisisobutyronitrile as the initiator to synthesize the surface-imprinted polymers. The development of the electrochemical sensor involved a detailed modification of the electrode, first by integrating carboxylated multi-walled carbon nanotubes and graphene oxide to improve its properties, and then by applying a suspension of MIPs to the glassy carbon electrode. This process resulted in a sensor capable of detecting chlorpyrifos in environmental samples with high sensitivity. The electrochemical sensor, designed for chlorpyrifos detection, exhibited a robust linear response in peak current to varying concentrations of chlorpyrifos, ranging from 1 x 10-11 to 1 x 10-5 mol L-1. It achieved a detection limit as low as 1.85 x 10-11 mol L-1 (S/N = 3). Testing confirmed the sensor's exceptional repeatability, stability, and high selectivity towards chlorpyrifos, underscoring its efficacy. The demonstrated capabilities of this sensor suggest its substantial potential for widespread use in pesticide regulation and environmental conservation efforts.