A molecular imprinting fluorescence sensor based on quantum dots and a mesoporous structure for selective and sensitive detection of 2,4-dichlorophenoxyacetic acid

A novel molecular imprinting fluorescence sensor was constructed by anchoring mesoporous structured imprinting microspheres on the surfaces of quantum dots (QDs) surface for the selective and sensitive detection of 2,4-dichlorophenoxyacetic acid (2,4-D) on the basis of an electron-transfer-induced fluorescence quenching mechanism. The resulting sensor was well characterized and had ideal spherical morphology and fluorescence properties. Under the optimized conditions, the sensor exhibited a satisfactory linearity within 0.66-80 mu M, with a low detection limit of 2.1 nM within 20 min. The sensor was successfully applied for the detection of 2,4-D in bean sprout samples, and high recoveries at three spiking levels of 2,4-D, ranging from 95.0 to 110.1%, with precisions below 4.9%, were attained. By taking advantage of surface imprinting and QDs, the sensor exhibited high sensitivity and good selectivity for the separation, enrichment and detection of 2,4-D in real food samples, thereby ensuring food safety. (C) 2017 Elsevier B.V. All rights reserved.