Excitation Wavelength Optimization of Europium-Doped Carbon Dots (Eu-CDs) for Highly Sensitive Detection of Tetracyclines in Water

Antibiotic contamination of water bodies has become a serious problem, which leads to aquatic life pollution and the development of antibiotic resistance. Hence, development of highly sensitive and selective optical sensors for antibiotic detection is at the forefront of scientific research. In this study, we present the synthesis of europium-doped carbon dots (Eu-CDs) and excitation wavelength optimization for the highly sensitive detection of tetracycline (TC) and TC-family antibiotics in water. An extensive physicochemical analysis and excitation wavelength optimization reveal that Eu-CDs can yield an exceptionally high limit of detection of TC at ∼5.8 nM over a linear range of 0.01-3 μM. Selectivity analysis with other common antibiotics revealed that the produced Eu-CDs are highly sensitive to TC and TC-group antibiotics only. A plausible mechanism for excitation-dependent TC detection by Eu-CDs is proposed. We firmly believe that the prepared Eu-CDs can be potentially employed for quick and sensitive monitoring of TC-family antibiotics in water samples.