Carbonized polymer dots for the sensitive and selective analysis of chlortetracycline based on the aggregation induced emission

In this study, carbonized polymer dots (CPDs) were first proposed for the quantitative detection of chlortetracycline (CTC) based on aggregation induced emission. CPDs were synthesized by a one-step hydrothermal assay using polyethylene imine as the sole precursor. CPDs showed bright blue fluorescence under UV light (λEx 350 nm and λEm 465 nm), with a quantum yield of 14.58%. There was a significant fluorescence enhancement for the CPDs + CTC system. When the concentration of CTC increased, the fluorescence color of CPDs displayed a significant change from bright blue to dark blue with the maximum emission shifting from 465 nm to 430 nm. Furthermore, the lifetime of CPDs + CTC increased from 7.12 ns to 11.26 ns, an increment of 4.14 ns, which was ascribed to the aggregation induced emission of CTC in the presence of CPDs. There was a good linear response between the fluorescence intensity of CPDs and the concentration of CTC from 0.1 μM to 120 μM with a limit of detection of 40 nM. Therefore, an excellent fluorescence probe was successfully prepared for the detection of CTC and its application in real samples was confirmed.