Excitation Wavelength\nOptimization of Europium-Doped\nCarbon Dots (Eu-CDs) for Highly Sensitive Detection of Tetracyclines\nin Water

Antibiotic contamination of water bodies has become a\nserious problem,\nwhich leads to aquatic life pollution and the development of antibiotic\nresistance. Hence, development of highly sensitive and selective optical\nsensors for antibiotic detection is at the forefront of scientific\nresearch. In this study, we present the synthesis of europium-doped\ncarbon dots (Eu-CDs) and excitation wavelength optimization for the\nhighly sensitive detection of tetracycline (TC) and TC-family antibiotics\nin water. An extensive physicochemical analysis and excitation wavelength\noptimization reveal that Eu-CDs can yield an exceptionally high limit\nof detection of TC at ∼5.8 nM over a linear range of 0.01–3\nμM. Selectivity analysis with other common antibiotics revealed\nthat the produced Eu-CDs are highly sensitive to TC and TC-group antibiotics\nonly. A plausible mechanism for excitation-dependent TC detection\nby Eu-CDs is proposed. We firmly believe that the prepared Eu-CDs\ncan be potentially employed for quick and sensitive monitoring of\nTC-family antibiotics in water samples.