Computational approach and ultrasound Probe-Assisted synthesis of magnetic molecularly imprinted polymer for the electrochemical detection of bisphenol A

A new theoretical approach based on density functional theory was developed to find the most suitable monomer and pomgen solvent to design a specific molecularly imprinted polymer (MIP) for bisphenol-A (BPA). Various theoretical investigations were carried out including HOMO and LUMO calculation, molecular electrostatic potential of the BPA-monomer interactions, and selection of the optimal monomer and porogen solvent using binding energies of BPA-monomer. Besides, counterpoise correction was used to avoid the problem of basis set superposition error. The theoretical results demonstrated that among virtual monomers, methacrylic acid and acrylamide showed good affinity towards BPA. The optimization of solvents was done using the polarizable continuum model and it was found that acetone was the most appropriate solvent. According to the obtained theoretical approach results, magnetic MIP (magMIP) was prepared using a high-power ultrasound probe. Scanning/transmission electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, and X-ray diffraction were used to characterize the as-prepared magMIP. Adsorption behavior was explained by Sips and pseudo-second-order models for isotherm and kinetic studies, respectively. Furthermore, magMIP showed favorable adsorption selectivity for BPA over other phenolic compounds. Finally, the developed magMIP was successfully used as a sorbent in solid-phase extraction combined with an electrochemical sensor for the detection of BPA. The obtained limit of detection was 66 nM and the recovery values in tap water sample were 104 and 105.5% for 2 and 10 mu M, respectively, with RSD values lower than 5 % (n = 3).

Automated summary

A new theoretical approach based on density functional theory was used to select methacrylic acid and acrylamide as the optimal monomers, as well as acetone as the most appropriate solvent for designing a magnetic MIP with good adsorption selectivity towards BPA. The developed magMIP showed favorable adsorption performance and was successfully applied for BPA detection, achieving a detection limit of 66 nM.