Preparation of molecularly imprinted ratiometric fluorescence sensor for visual detection of tetrabromobisphenol A in water samples.

A sensitive molecularly imprinted ratiometric fluorescence sensor was constructed for the first time to visually detect tetrabromobisphenol A (TBBPA). The blue fluorescent carbon quantum dots (CQDs) were coated with SiO through the reverse microemulsion method to obtain a stable internal reference signal CQDs@SiO. The ratiometric fluorescence sensor was finally prepared using red fluorescent CdTe QDs as the response signal in the presence of CQDs@SiO. When the molecularly imprinted polymers were combined with TBBPA, the fluorescence of CdTe QDs (Ex = 365 nm, Em = 665 nm) was rapidly quenched, while that of CQDs (Ex = 365 nm, Em = 441 nm) remained stable, resulting in a noticeable fluorescence color change. Moreover, the fluorescence intensity ratio (I/I)/(I/I) of the sensor showed a linear response to TBBPA in the concentration range 0.1 to 10 μM with a low detection limit of 3.8 nM. The prepared sensor was successfully applied to detect TBBPA in water samples. The recoveries were in the range 98.2-103%, with relative standard deviations lower than 2.5%. Furthermore, a fluorescent test strip for visual monitoring of TBBPA was constructed to streamline the procedure. The excellent results demonstrate that the prepared test strip has a broad prospect for the offline detection of pollutants.