Dual-template molecularly imprinted magnetic covalent organic framework for selective extraction of bisphenols

Covalent organic frameworks (COFs) are promising porous materials for sorption and extraction applications. However, their selectivity in molecular recognition poses a significant challenge, primarily due to the constraints imposed by their rigid structural design. Additionally, the detection of phenols in water remains a tricky issue due to the competitive adsorption between water molecules and phenolic compounds, influenced by hydrogen bonding interactions. Herein, we present a sophisticated strategy for the design and synthesis of dual-template molecularly imprinted polymer core–shell magnetic covalent organic frameworks (DMIP-MCOFs), which was applied to magnetic solid-phase microextraction (MSPE) of bisphenol compounds (BPs) in environmental water samples. Double template molecules (BPA and BPB) are introduced to enhance selectivity for BPs recognition. The inherent porosity and active sites within COFs strengthen the hydrogen bonding and π-π interactions between the target BPs and the DMIP-MCOFs, with capillary action serving as the driving force. Coupling DMIP-MCOFs based MSPE with HPLC-UV resulted in low detection limits of 0.22 ∼ 0.85 μg/L and good precision with relative standard deviations (RSDs) for inter-day and intra-day extractions of BPs are ranging from 4.60 % to 9.30 % and 3.45 % to 8.42 %, respectively. The satisfactory recoveries (79.57 % ∼ 109.68 %) for simultaneous analysis of four BPs were obtained. This work provides a novel approach for selective recognition of bisphenol compounds in real water samples.