Detection of Tetracycline in Farm Wastewater by Nitrogen-doped Carbon Quantum Dots

The detection of tetracycline antibiotics in environmental waters is crucial due to their widespread use, persistence, and potential toxicity. Herein, a method for the specific detection of tetracycline in aquaculture wastewater using a nitrogen-doped carbon quantum dots fluorescence probe is reported. Nitrogen-doped carbon quantum dots (N-CQDs) were synthesized in one step via a hydrothermal method, employing citric acid as the carbon source and diethylenetriamine as the nitrogen source. The resulting N-CQDs exhibit excellent stability, solubility and fluorescence properties. Upon the introduction of tetracycline, a fluorescence burst can be observed, indicating that the N-CQDs function as a ratio fluorescence probe. The fluorescence burst phenomenon is primarily due to the internal filtering effect. In the case of N-CQDs, this burst is attributed to the overlap between the absorption spectrum of tetracycline and the emission spectrum of the carbon quantum dots, which results in internal filtering. The linear range for tetracycline detection spans from 54.2 nM to 0.8 μM, with a detection limit of 54.2 nM. The developed fluorescence probe shows potential for application in detecting tetracycline in real water samples.