Aggregation-induced emission enhancement N, S-CQDs for selective detection of CIP in the environment

Carbon quantum dots (CQDs) have been extensively researched as fluorescent probes, but there are few reports on fluorescence-enhanced probes. Herein, nitrogen and sulfur co-doped CQDs (N, S-CQDs) with blue aggregation-induced emission enhancement (AIEE) fluorescence were synthesized by a one-step hydrothermal reaction. N, S-CQDs can rely on the presence of -OH, C=O, -NH₂, and ether bonds on their surfaces and the formation of hydrogen bonds by ciprofloxacin (CIP) containing Ar-F and -COOH functional groups to achieve effective charge transfer. In addition, CIP forces N, S-CQDs to aggregate to form cross-linked structures, which effectively limits the vibration and rotation of N, S-CQDs, leading to enhanced fluorescence of N, S-CQDs. Based on the above intermolecular charge transfer and AIEE between N, S-CQDs and CIP, an efficient and sensitive nano fluorescent probe for the detection of CIP in real water samples was developed, which can achieve sensitive detection of 3.33 × 10^-8-1.13 × 10^-6M CIP.