Molecularly imprinted fluorescence assay based on lead halide perovskite quantum dots for determination of...

Molecularly imprinted polymers with methylammonium lead halide perovskite quantum dots (MIP@MAPbBr₃ PQDs) have been prepared and applied to the determination of benzo(a)pyrene (BaP) for the first time. The photoluminescence (PL) of MIP@MAPbBr₃ PQDs was enhanced due to the surface passivation of defects by BaP. PL excitation and emission spectra, X-ray diffraction, Fourier transform infrared, and time-resolved PL studies suggest that the interaction between MIP@MAPbBr₃ PQDs and BaP is a dynamic process. After MIP@MAPbBr₃ PQDs were incubated with BaP, the benzene ring in the molecular structure of BaP can interact with MIP@MAPbBr₃ PQDs through π electrons, which reduces non-radiative recombination of MIP@MAPbBr₃ PQDs and lengthens excited state lifetime. The PL intensity of the MIP@MAPbBr₃ PQDs-BaP system was monitored at 520 nm with 375 nm excitation. Under optimized conditions, the PL intensity of MIP@MAPbBr₃ PQDs is linear with the concentration of BaP in the 10 to 100 ng·mL^-1 range, with a detection limit of 1.6 ng·mL^-1. The imprinting factor was 3.9, indicating excellent specificity of MIP@MAPbBr₃ PQDs for BaP. The MIP@MAPbBr₃ PQDs were subsequently applied to the PL analysis of BaP in sunflower seed oil, cured meat, and grilled fish samples, achieving recoveries from 79.3 to 107%, and relative standard deviations below 10%. This molecularly imprinted fluorescence assay improves the selectivity of BaP in complex mixtures and could be extended to other analytes.