Fabrication of fluorescence sensor based on semi-covalent dummy molecularly imprinted silica on silane-modified carbon quantum dot for highly selective and sensitive detection of bisphenol A in spirits

Abstract

Spirits, a Chinese liquor, is susceptible to bisphenol A (BPA) contamination during production and storage. Therefore, developing an accurate and sensitive method for BPA detection in spirits samples is necessary. In this study, a fluorescence sensor (Si-CQDs@DMIPs) with a low detection limit for BPA was synthesized by combining semi-covalent dummy molecular imprinting and silane-modified carbon quantum dot (Si-CQD) techniques. The structure, morphology, and fluorescence properties of Si-CQDs@DMIPs were investigated using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and fluorescence spectroscopy (FS). The principle of the selective recognition and detection of BPA by the prepared Si-CQDs@DMIPs is that the molecular imprinting layer can selectively capture BPA and quench the fluorescence intensity of Si-CQDs, due to the electron transfer from BPA to the Si-CQDs. Under optimal conditions, the fluorescence intensity of Si-CQDs@DMIPs sensor showed a good linear decrease (R2 > 0.99) when BPA concentration was 6–1800 nmol/L, and the detection limit was 0.65 nmol/L (3 σ/S). When applied to spirits samples, Si-CQDs@DMIPs exhibited recovery rates between 81.5% and 93.8% with relative standard deviations (RSDs, n = 5) of 3.0–5.8% (spiked at 50, 200, 500, and 1000 nmol/L). Overall, Si-CQDs@DMIPs enable the highly selective and sensitive direct measurement and rapid screening of BPA in spirits.