Dual-emission carbon dots with UV-induced fluorescence enhancement: Construction of fluorescence sensor array and ratiometric probe for discrimination and detection of antibiotics.

BACKGROUND: The overuse of multiple antibiotics has rendered the problem of multi-residues of antibiotics, which poses a serious threat to food and ecological safety. However, the simultaneous detection of multiple antibiotics currently relies heavily on traditional instrumental analysis, which severely limits detection efficiency and narrows their applicable scenarios. Although array-based sensing methods enable multi-target detection, they suffer from drawbacks of complex array construction and insufficient quantitative capability. Therefore, developing simple sensor arrays for the discrimination and quantification of multiple antibiotic residues is of great importance for ensuring food safety and environmental health. RESULTS: Herein, a fluorescence sensor array and a ratiometric probe were developed based on dual-emission carbon dots (D-CDs) for the discrimination and quantification of five nitroimidazole antibiotics (NIIMs). The D-CDs synthesized via hydrothermal method exhibited dual emission at 430 nm and 600 nm. NIIMs minimally affect the 430 nm fluorescence but enhance 600 nm emission with color transition from blue to orange, forming unique fingerprints. A one-component dual-channel sensor array was thus developed for the discrimination of five NIIMs with an accuracy of 96-100%. To compensate for the array's deficiency in quantification, a D-CDs based ratiometric fluorescent probe was also developed for quantitative detection of five NIIMs (MNZ, ONZ, SNZ, TNZ, and RNZ), achieving detection limits of 0.52, 0.58, 0.19, 0.49, and 0.23 μM, respectively. Furthermore, a rapid colorimetric platform integrated with a smartphone was established for on-site NIIM quantification. Practical applicability was validated in real samples, with an average recovery rate of 110.90% and RSD of 0.86-8.57%. SIGNIFICANCE: The sensor array and ratiometric probe constructed based on D-CDs not only achieve the simultaneous discrimination of multiple antibiotics but also realize the quantitative detection of individual antibiotics. This simple and effective strategy for fabricating sensor arrays and ratiometric probes, provides a promising technique for rapid on-site detection of multiple contaminants in complex food and environmental matrices with high reliability.