A NIR-responsive up-conversion nanoparticle probe of the NaYF:Er,Yb type and coated with a molecularly imprinted polymer for fluorometric determination of enrofloxacin.

The paper describes the preparation of a fluorescent probe based on the use of up-conversion particles (UCPs) of the type NaYF: Er, Yb and shelled with a molecularly imprinted polymer (MIP) that is specific for the antibiotic enrofloxacin. The upconverted green luminescence emitted by the UCPs upon photoexcitation at 980 nm was used to locally generate a thin MIP shell around the UCPs via photopolymerization. Enrofloxacin is used as the template, and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent. It is found that enrofloxacin is well captured by the MIP and then quenches the fluorescence of the UCPs. Fluorescence decreases linearly in the 63 ng·L to 60 μg·L enrofloxacin concentration range, with a 8 ng·L limit of detection. The method was applied to the determination of enrofloxacin in spiked fish samples. Recoveries ranged from 83.7 to 87.7%, with relative standard deviations between 2.0 and 5.5% (for n = 3). [ABSTRACT FROM AUTHOR]