Molecularly imprinted polydopamine coated CdTe@SiO2 as a ratiometric fluorescent probe for ultrafast and visual p-nitrophenol monitoring

Molecular imprinted ratiometric fluorescent analysis method has been a popular method for the quantitative and qualitative tests of target analysis yet encounters low detection efficiency caused by the deep embedment and uneven distribution of fluorescent monomers, even the embedding rate of fluorescent monomer directly affects the visual detection effect. Herein, the ratiometric fluorescent molecularly imprinted polymers (F-PDA/CdTe QDs@SiO2@MIPs) based fluorescent polydopamine (F-PDA) and CdTe quantum dots (CdTe QDs) was successfully synthesized to detect p-nitrophenol (p-NP) selectively and visually. F-PDA was firstly used in the synthesis of ratiometric fluorescent molecularly imprinted polymers to serve as both fluorescent monomer and functional monomer, which greatly shorten the detection time while reducing the fluorescence loss caused by polymer coating. The test results showed that the p-NP quenched the fluorescent of F-PDA via electron transfer. Meanwhile, F-PDA/CdTe QDs@SiO2@MIPs enabled to visually detect a low detection limit of p-NP (56.68 nM) within 2.0 min by naked eyes. The detection time was as fast as quantum dots detect targets directly and the detection limit was well below the standard concentration of p-NP in drinking water. Finally, the F-PDA/CdTe QDs@SiO2@MIPs realize the detection of p-NP in the drinking and wastewater respectively.