Ion imprinted-carbon paste electrode as electrochemical sensor for ultra-trace recognizing speciation of mercury

Monitoring and determination of mercury species in the environment is a challenging issue. This work presents an electrochemical sensor based on voltammetric methods for selective recognition of Hg species using carbon paste electrode modified Hg²⁺-imprinted polymers. The ion-imprinted polymers were prepared by thermal bulk polymerization with Hg(NO₃)₂, 1,5-dipenylcarbazone (DPC), and ethylene glycol dimethacrylate (EGDMA) as template, ligand, and monomer, respectively. The surface properties of the electrode were characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, thermal gravimetric analysis, electrochemical impedance spectroscopy, and cyclic voltammetry. In addition, differential pulse voltammetry was used to evaluate the electrochemical properties of the proposed sensors. The designed sensor was shown a wide linear range between 0.1 and 40 μM with a limit of detection (LOD) at 70 nM (3σ). The sample analysis found that the sensor has good stability and selectivity for mercury speciation with a %recovery of 98–103 %.