Highly Selective Detection of Metronidazole by Self-Assembly via 0D/2D N-C QDs/g-CN Nanocomposites Through FRET Mechanism.

A 0D/2D (0-dimensional/2-dimensional) nanostructure was designed by self-assembly of N-C QDs and carboxylated g-CN nanosheets and used as a fluorescence resonance energy transfer (FRET) fluorescent sensor. The N-C QDs/g-CN nanosheets were synthesized via the amino group on the N-C QD surface and the -COOH of the carboxylated g-CN nanosheets. The mechanism of detection of metronidazole (MNZ) by N-C QDs/g-CN nanocomposites is based on FRET between negatively charged N-QDs and positively charged carboxylated g-CN nanoparticles. N-C QDs/g-CN nanostructures displayed good responses for the detection of MNZ at normal temperature and pressure. The decrease in the fluorescence intensity showed a good linear relationship to MNZ concentration within 0-2.6 × 10 mol/L, and the detection limit was 0.66 μM. The novel FRET sensor will have a great potential in clinical analysis and biological studies.