Development of an Electrochemical Sensor Based on Covalent Molecular Imprinting for Selective Determination of Bisphenol-A

In this study, an electrochemical sensor was developed and used for selective determination of bisfenol-A (BPA) by integrating sol-gel technique and multi-walled carbon nanotubes (MWCNTs) modified paste electrode. BPA bounded by covalently to isocyanatopropyl-triethoxy silane (ICPTS) was synthesized as a new precursor (BPA-ICPTS) and then BPA-imprinted polymer (BPA-IP) sol-gel was prepared by using tetramethoxysilane (TMOS) and BPA-ICPTS. Non-imprinted polymer (NIP) sol-gel was obtained by using TMOS and (3-Aminopropyl) triethoxysilane. Both BPA-IP and NIP sol-gels were characterized by nitrogen adsorption-desorption analysis, FTIR, SEM, particle size analyzer and optical microscope. Carbon paste sensor electrode was fabricated by mixing the newly synthesized BPA-IP with MWCNTs, graphite powder and paraffin oil. The electrochemical characterization of the sensor electrode was achieved with cyclic and differential pulse voltammetric techniques. The response of the developed sensor under the most proper conditions was linear in BPA concentration range from 4.0×10⁻⁹ to 1.0×10⁻⁷ mol L⁻¹ and 5.0×10⁻⁷ to 5.0×10⁻⁵ mol L⁻¹ and the detection limit was 4.4×10⁻⁹ mol L⁻¹. The results unclosed that the proposed sensor displayed high sensitivity and selectivity, superior electrochemical performance and rapid response to BPA.