Light-controlled molecular recognition of aflatoxins using azobenzene photo-switchable molecularly imprinted...

Early detection of aflatoxins is crucial to safeguard food safety. In this study, a new azobenzene monomer was synthesized and its photo-isomerization behavior in methanol and dimethyl sulfoxide was studied. A photo-switchable molecularly imprinted polymer (PMIP) designed for selectively recognizing aflatoxin B1 (AFB1) was fabricated via a surface imprinting technique. A dummy template, 5,7-dimethoxycoumarin was incorporated during the polymerization process. The photo-responsive behaviors of candidate monomers were systematically evaluated in methanol and dimethyl sulfoxide. The resulting PMIP was used as an extraction adsorbent for pretreatment prior to high-performance liquid chromatography-mass spectrometry analysis with its adsorption capacity could be controlled by light irradiation (365 nm and 440 nm). The method demonstrated a linear calibration interval from 50 to 1000 ng·mL⁻¹ with detection limit of 5.1 ng·mL⁻¹, and exhibited favorable binding capacity values between 90.8% and 95.4% when used for the determination of AFB1 in corn, reflecting the strong recognition affinity of PMIP toward AFB1.