Characterization and application of molecularly imprinted polymer-coated quantum dots for sensitive fluorescent determination of diethylstilbestrol in water samples

Abstract

Molecularly imprinted silica layers coated to quantum dots (MIP-QDs) were successfully fabricated and applied as the fluorescence probe for highly selective and sensitive determination of diethylstilbestrol (DES). Scanning electron microscopy, Transmission electron microscopy, and Fourier transform infrared spectroscopy indicated successful grafting of molecularly imprinted silica layers onto the surface of QDs. Furthermore, the fluorescence assay based on the MIP-QDs showed excellent selectivity and fluorescence quenching capability in optimal conditions and a good linear relationship was obtained in the range of 2.0 × 10−4–10.0 mg/L with a correlation coefficient of 0.9980. The limit of detection of 5.9 × 10−5 mg/L was acquired. Good recoveries ranging from 95.5% to 107.5% were achieved with relative standard deviations (RSD) below 8.4% for seawater and river water samples. The fabricated MIP-QDs were successfully employed as the recognition and response element of an microtitration 96-well fluorescence detection system. Good recoveries ranging from 82.9% to 102.0% with RSDs below 10.0% were obtained for seawater and river water samples. Results demonstrate that simple, rapid, and sensitive DES determination method based on MIP-QDs can be successfully applied to DES residue detection in seawater and river water samples.