Molecularly Imprinted Electrochemical Sensor Based on Magnetic Mesoporous Nanocarriers for Sensitive Detection of Tetrabromobisphenol A

Tetrabromobisphenol A (TBBPA) residues are commonly found in sediments, soil, and sewage, necessitating the development of sensitive methods for its detection in environmental samples due to its potential cytotoxicity and hepatotoxicity. A molecularly imprinted electrochemical sensor, incorporating a magnetic surface molecularly imprinted polymer (SMIP) and an MXene/Au nanocomposite, has been designed for the selective detection of TBBPA. The synergistic effect between MXene and Au nanoparticles significantly enhances the electrochemical signal, thereby resulting in superior sensitivity of the sensor. SMIP was prepared by surface-initiated reversible addition–fragmentation chain transfer polymerization with magnetic mesoporous nanosilica (Fe₃O₄@mSiO₂) as the carrier. Magnetic mesoporous SiO₂ nanoparticles, which combine the advantages of magnetic responsiveness and high specific surface area, not only facilitate the efficient separation of imprinted polymers from liquid mediums under the influence of an external magnetic field but also provide more imprinting sites for SMIP, significantly improving the recognition efficiency. The glassy carbon electrode was sequentially modified with Fe₃O₄@mSiO₂@SMIP and the MXene/Au nanocomposite to achieve specific recognition sites and increased response in electrochemical signals. Density functional theory was employed to optimize the functional monomer and the molar ratio between the template molecule and functional monomer. In addition, variables like pH and incubation time were also optimized to achieve the best detection performance. The current response was linear with TBBPA concentration ranging from 1–4500 nM. The detection limit of the sensor is 0.83 nM. The prepared sensor was successfully used to detect TBBPA in water samples with the recovery ranging from 96.0% to 104.0%. The results indicate that the sensor has wide prospects in the detection of TBBPA in tap water and river water.