Dual-emission ratiometric fluorescence sensors based on silica, molecularly imprinted polymers and carbon quantum dots for high-sensitivity and high-selectivity detection of sulfadiazine

In this work, a dual-emission ratiometric fluorescence sensor was prepared and used for the detection of sulfadiazine (SDZ) drug. The hydrothermal method was used to synthesize carbon quantum dots (CQD) (fluorescence response signal) and sulfhydryl-modified cadmium telluride quantum dots (fluorescence reference signal), and a molecularly imprinted polymer was subsequently synthesized. After eluting the template molecule SDZ, the blot recognition site remains on the surface of the imprinted polymer. During the process of detection, due to electron transfer between SDZ and CQDs, holes of stimulated electrons are filled. This leads to fluorescence quenching at around 430 nm, which greatly improves sensor selection performance. Compared with traditional single-emission fluorescence sensors, ratiometric fluorescence sensors have a wider linear range and higher detection accuracy. Under the optimal conditions, the sensor exhibited excellent performance in terms of low detection limit (4.2 nmol L −1 ) and satisfactory linear range (2–20 μmol L −1 ). This intelligent response change mode also provides prospect for detection of other sulfonamide antibiotics and offers a reference to signal transform for other molecular imprinting technologies. © 2023 Society of Industrial Chemistry.