Development of a Molecularly Imprinted Pencil Graphite Electrode for the Voltammetric Detection of Hg²⁺ Ions

The ability to detect trace amounts of mercury has become critical due to its possible severe toxic effects on both humans and the environment when exposed to unsafe amounts. This study focuses on developing a novel mercury detection technique using differential pulse anodic stripping voltammetry (DPASV) with a pencil graphite electrode modified with a molecularly imprinted polymer (MIP-PGE). The amino acid-based N-methacryloyl-(L)-cysteine methyl ester (MAC) monomer was used for the imprinting process of Hg²⁺ ions. Fourier transform infrared spectroscopy equipped with an attenuated total reflection (FTIR-ATR), contact angle (CA), and scanning electron microscopy (SEM) was used to characterize the electrochemical sensors. The obtained results revealed that the voltammetric detection method using MIP-PGE was able to accurately detect Hg²⁺ in both aqueous solutions and real samples for different concentrations, with an acceptable linear relationship. This novel sensor demonstrated low detection and quantification limits of 0.188 nM and 0.570 nM, respectively. The produced sensor offers rapid, simple, and cost-effective detection of Hg²⁺ ions.