Fluorescent Molecularly Imprinted Polymer Sensor Prepared Using Mesoporous Silica as Carrier for Sensitive and Accurate Detection of Bisphenol A

A fluorescent molecularly imprinted polymer (FMIP) sensor for sensitive detection of bisphenol A (BPA) was constructed based on surface-initiated reversible addition fragmentation chain transfer (SI-RAFT) polymerization with mesoporous silica (mSiO ₂ ) as the carrier. In this work, N-allyl-4-ethylenediamine-1, 8-naphthalimide was used as the fluorescent functional monomer and mSiO ₂ as the carrier. The high specific surface area of mSiO ₂ carrier providing more imprinting sites for the FMIP and thereby effectively enhances recognition efficiency of obtained imprinted polymer. Azide groups were initially grafted onto the mSiO ₂ surface, and then alkynyl-functionalized RAFT agent was introduced via copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. The FMIP was synthesized by RAFT polymerization using BPA as the template, methacrylic acid (MAA) as the functional monomer. When the template BPA rebinds to the imprinting cavity, the fluorescence signal of the MIP-capped N-allyl-4-ethylenediamine-1, 8-naphthalimide can be efficiently quenched. The ratio of fluorescence intensity exhibited a linear response to the concentrations of BPA ranging from 0 to 80 µM, achieving a detection limit of 0.43 µM. Moreover, the FMIP sensor was effectively used to detect BPA in real samples, with recovery rates ranging from 96.55% to 102.25% and a relative standard deviation (RSD) of 0.4%-1.57%. The results indicate that the prepared FMIP sensor shows great potential for the detection of BPA in environmental medium.