Upconversion particle@Fe3O4@molecularly imprinted polymer with controllable shell thickness as high-performance fluorescent probe for sensing quinolones

Localized photo-polymerization was ingeniously applied to prepare a multifunctional molecularly imprinted polymer (MIP) fluorescent probe using the “layer-by-layer” assembly of MIP and Fe 3 O 4 nanoparticles on NaYF 4 : Yb 3+ , Er 3+ upconversion particles (MUCPs@MIP). Enrofloxacin was used as the template and chosen as the target molecular during the investigation of the adsorption property. This ternary probe has magnetic and broad-spectrum molecular recognition capability, fast response, and upconversion fluorescence. The results of the fluorescence quenching analysis showed good linear ranges of 1.03   nmol/L to 0.28   μmol/L for enrofloxacin, 1.69   nmol/L to 0.22   μmol/L for fleroxacin , 6.92   nmol/L to 0.28   μmol/L for levofloxacin , 7.54   nmol/L to 0.30   μmol/L for ciprofloxacin , and 3.90   nmol/L to 0.25   μmol/L for enoxacin . This probe was further used to determine five quinolones in fish tissues and the recoveries ranging from 90.33% to 108.43% were obtained with relative standard deviation below 5.53%. This work offers a new and general strategy to synthesize a MUCPs@MIP upconversion fluorescence probe with magnetic and selective molecular recognition capability for rapid and accurate sensing of multiple chemical residues in the environment and agri-food products.