Green synthesis of a deep-ultraviolet carbonized nanoprobe for ratiometric fluorescent detection of feroxacin and enrofloxacin in food and serum samples

Recently, the development of a novel fluorescent (FL) nanoprobe for ratiometric detection of antibiotics in real-world samples has received more and more attention. In this article, the distinctive optical properties of deep-ultraviolet emission, a narrowed full width at half maximum (∼20 nm) and excitation-independent emission of a carbonized nanoprobe (CNP) were easily prepared by an environmentally friendly approach of solvothermal treatment using melamine as the precursor and H 2 O as the solvent. The obtained CNP can be further utilized as an efficient ratiometric FL nanoprobe for enrofloxacin (EFC) and feroxacin (FXC) detection based on the fact that the FL quenching of the CNP was accompanied by an FL increase with EFC/FXC based on the inner filter effect (IFE). Under the optimal conditions, excellent linear relationships existed between the relative FL intensity (FL 290 nm /FL 412 nm , CNP for FL 290 nm and antibiotics for FL 412 nm ) and the concentrations of FXC and EFC in the range of 0.05-500.0 μM and 0.05-200.0 μM, with limits of detection of 21.74 and 22.43 nM (3 σ / k ), respectively. With the proposed ratiometric FL sensor, FXC and EFC in milk and serum samples can be rapidly and selectively analyzed without tedious pretreatment processes for real-world samples. A sensitive ratiometric fluorescent probe for EFC and FXC detection in milk and bovine serum samples based on the internal filtration effect.