Construction of carbon dots/metal–organic framework composite for ratiometric sensing of norfloxacin

Abstract

Quinolone antibiotics such as norfloxacin (NFX) are widely used to treat many bacterial infections, but antibiotic residues in water and food will worsen the pathogenesis of resistant bacteria, and long-term use of antibiotics leads to drug resistance. Hence, we designed and synthesized the composite of green carbon dots and UiO-66 (g-CDs@UiO-66) as a fluorescent sensing material by integrating carbon dots, which are rich in hydroxyl and carboxyl groups, into the zirconium-based metal–organic framework UiO-66 through the solvothermal method. This composite possesses the excellent optical properties of g-CDs and the selective response and the enrichment of UiO-66 to the target analytes, which can be applied to the detection of norfloxacin in milk and pork samples. The results prove that g-CDs@UiO-66 shows a good performance in the detection of norfloxacin with a limit of detection (LOD = 0.082 μM) in the linear range of 1–8 μM. Further research indicates that the presence of strong hydrogen bonds between g-CDs@UiO-66 and norfloxacin is the main reason for the fluorescence enhancement, and provides a new approach to the development of fluorescent nanosensing technology in the field of food and environmental safety inspection.