Rapid detection of aflatoxin B₁ by dummy template molecularly imprinted polymer capped CdTe quantum dots

A novel and sensitive fluorescent sensor was synthesized for the rapid and specific recognition of aflatoxin B₁ (AFB1) by our combining molecular imprinting techniques with quantum dot technology. Molecularly imprinted polymers coated CdTe quantum dots (MIP@CdTe QDs) were prepared through the Stöber method with 5,7-dimethoxycoumarin as a dummy template. 3-Aminopropyltriethoxysilane was selected as the functional monomer, and tetraethyl orthosilicate was used as the cross-linking agent. The best molar ratio of 5,7-dimethoxycoumarin to functional monomer to cross-linker was 4:20:15. The MIP@CdTe QD composites were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, and fluorescence spectroscopy. Under the optimum conditions, the relative fluorescence intensity of the MIP@CdTe QDs showed adequate linearity with AFB1 concentration over the range from 80 to 400 ng/g. The detection limit is 4 ng/g, according to 3s/K. Finally, the method was successfully applied to the quantitative determination of AFB1 in real samples. The spike recoveries at different spiking levels ranged from 99.20% to 101.78%, which were consistent with those measured by ultrahigh-performance liquid chromatography-mass spectrometry. The method developed for AFB1 detection lays the foundation for rapid detection of trace amounts of other exogenous harmful substances in a complicated matrix.