Solvothermal synthesis of nitrogen-doped carbon quantum dots for the sensitive detection of azithromycin

Carbon quantum dots are widely used in various drug detection applications because of their excellent photoluminescence properties. However, there are few reports about the detection of macrolide antibiotics. In this work, blue emitting nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by using a hydrothermal method, which exhibit the most prominent emission band at 464 nm at an excitation wavelength of 414 nm. And it was found that Cu²⁺alone or the macrolide antibiotic azithromycin had no significant effect on the fluorescence intensity of N-CQDs. Still, when the two were mixed, they quenched the fluorescence of N-CQDs. Based on this, a fluorescence assay for azithromycin were developed. The fluorescence of the mixture of N-CQDs and Cu²⁺showed good linearity with azithromycin (0.52-42.2μM) with a low detection limit of 0.52μM.