Rapid determination of malachite green in water and fish using a fluorescent probe based on CdTe quantum dots coated with molecularly imprinted polymer

A fluorescent probe based on CdTe quantum dots (QDs) coated with molecularly imprinted polymers (MIPs) was fabricated for the determination of malachite green (MG) by the strategy of fluorescence resonance energy transfer (FRET). The MIP-coated QDs were synthesized through precipitation polymerization using acrylamide and ethylene glycol dimethacrylate as monomer and cross-linker, respectively. The optimum molar ratio of MG, monomer and cross-linker was 1:8:40 in 60   mL of acetonitrile, and the polymerization time was 28   h. The MIP-coated QDs, with an average diameter around 290   nm, showed excellent fluorescence emission in 500–700   nm at λ ex 370   nm. The probe exhibited fluorescence quenching response to MG selectively within only 5   min at the concentrations from 0.1 to 20   μmol   L −1 . The fluorescent probe was successfully used to detect MG in water and fish samples with a detection limit of 0.059   μmol   L −1 (3 σ , n   =   9). The spiked recoveries, from 94.8% to 98.1% for water samples, and 98.1% to 106.2% for fish samples, respectively, indicated that the as-prepared MIP-coated QDs could be used as a fluorescent probe to detect MG rapidly in water and fish samples.