Interface-specific molecularly imprinted dual-emission carbon dots for selective detection of catechol

Benzenediol isomers, including catechol (CT), resorcinol (RS), and hydroquinone (HQ), are widespread environmental pollutants with nearly identical molecular structures and physicochemical properties, posing significant challenges for their selective detection in aqueous systems. Among them, CT is of particular concern due to its high toxicity to aquatic organisms and potential risks to human health. Conventional detection methods often exhibit insufficient selectivity and sensitivity in complex matrices. Herein, we report a dual-emission ratiometric fluorescent sensor integrating molecularly imprinted polymers (MIPs) with blue and yellow carbon dots (B-CDs@MIPs/Y-CDs) for the selective recognition and quantification of CT in aqueous media. The sensor operates via a ratiometric fluorescence mechanism, in which CT selectively quenches the blue emission of B-CDs while the yellow emission of Y-CDs remains constant, serving as an internal reference. The molecularly imprinted layer introduces highly specific binding sites at the nanoscale interface, conferring outstanding selectivity toward CT over its structural isomers RS and HQ. The sensor exhibited an imprinting factor of 2.73, a wide linear detection range (5.0–500 μg/mL), a low detection limit (0.15 μg/mL), and excellent anti-interference capability. Furthermore, successful application to real water samples with recoveries of 90.3–110.5 % verified its analytical reliability and practical feasibility in complex matrices. This work demonstrates a versatile strategy for isomer-level molecular recognition through interface-engineered dual-color carbon dots combined with molecular imprinting technology. The proposed sensor effectively addresses the challenge of selectively detecting structurally similar pollutants and provides a promising platform for sensitive, selective, and practical fluorescence-based environmental monitoring.