Fluorescent polydopamine based molecularly imprinted sensor for ultrafast and selective detection of p-nitrophenol in drinking water

A highly effective fluorescent molecularly imprinted sensor (F-PDA-MIS) based on fluorescent polydopamine (F-PDA) was successfully synthesized for selective and ultrafast detection of p-nitrophenol (P-NP) in drinking water. F-PDA with abundant surface functional groups has been artfully modified to firstly serve as both fluorescent monomer and functional monomer in the synthesis of a uniform luminous F-PDA-MIS, which can greatly improve the detection efficiency. As expected, F-PDA-MIS had an obvious emission wavelength of 535 nm with the optimal excitation wavelength at 400 nm. Specially, F-PDA-MIS could detect P-NP in the range 100 to 1100 nM with much lower detection limit of 24.2 nM within 120 s compared with other conventional imprinted fluorescent sensors based on pure quantum dots (QDs) or dyes. This excellent test phenomenon is mainly ascribed to the rapid electron transfer between F-PDA and P-NP. Satisfactory recovery of 98.0–104% for mineral water and 98.6–106% for boiling water were obtained with relative standard deviations (RSDs) of 2.7–3.4% and 2.6–3.5% respectively. The detection reliability of F-PDA-MIS was verified by the comparison with high-performance liquid chromatography (HPLC–UV). Consequently, F-PDA as a fluorescence functional monomer has been shown to be a possible strategy to effectively improve the detection limit and shorten response time of the target determination in water. Graphical abstract: [Figure not available: see fulltext.].