Ionic liquid-sensitized molecularly imprinted polymers based on heteroatom co-doped quantum dots functionalized...

Ionic liquid-sensitized molecularly imprinted polymers (MIPs) based on Mn and Cu co-doped ZnIn₂S₄ quantum dots functionalized graphene (QDs-G@ILMIPs) were prepared by a one-pot facile polymerization at room temperature. Here, the ionic liquid was used as functional monomers to provide chemical bonds for the recognition sites of target molecules. The ionic liquid was also used to improve the selectivity and adsorption capacity, and enhance the fluorescence stability and sensitivity of the MIPs for surface modification. Additionally, the Mn/Cu co-doped ZnIn₂S₄ quantum dots could play a synergistic role in avoiding the toxicity of the heavy metals, and enhance the fluorescence performance. An increased efficiency and sensitivity of QDs-G@ILMIPs was obtained owing to the use of graphene with its large specific surface area, which effectively increased the number of binding sites to facilitate the electron transfer process. The turn-off fluorescence spectra of QDs-G@ILMIPs decreased sharply with an increasing concentration of the λ-cyhalothrin standards within the range from 1 to 350 μg g^-1. The detection limit of QDs-G@ILMIPs was 0.246 μg g^-1. Furthermore, the QDs-G@ILMIPs toward λ-cyhalothrin detection in real samples, as well as its recovery, reproducibility and stability, proved that the QDs-G@ILMIPs could be extensively applied for the accurate detection of pesticide residues in food samples.