In this paper, rhodamine 6G (Rh 6G) was modified on the surface of carbon quantum dots (CQDs) synthesized by the hydrothermal method through microwave reaction, and Rh 6G-CQDs (R-CQDs) with...

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 3.33×10-8–1.13×10-6 M CIP.

Carbon quantum dots are widely used in various drug detection applications because of their excellent photoluminescence properties. However, there are few reports about the detection of macrolide antibiotics. In this work, blue emitting nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by using a hydrothermal method, which exhibit the most prominent emission band at 464 nm at an excitation wavelength of 414 nm. And it was found that Cu2+ alone or the macrolide antibiotic azithromycin (AZI) had no significant effect on the fluorescence intensity of N-CQDs. Still, when the two were mixed, they quenched the fluorescence of N-CQDs. Based on this, A fluorescence assay for azithromycin were developed. The fluorescence of the mixture of N-CQDs and Cu2+ showed good linearity with azithromycin (0.52-42.2 μM ) with a low detection limit of 0.52 μM.

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A hydrothermal method for preparing water‐soluble carbon quantum dots (CQDs) was studied using the citric acid and thiourea. The CQDs have high fluorescence Intensity, high photoluminescence stability and uniform size. Their average size is 5 nm. Their maximum excitation and emission wavelengths are 364 and 452 nm, respectively. divalent copper ions can quench the fluorescence of CQDs and captopril can interact with divalent copper ions to form complexes, the complexes can further reduce the fluorescence of CQDs due to self‐absorption, and there was a linear relationship between the ratio of the fluorescence intensities before and after adding captopril and the captopril concentration. A novel, simple, and environmentally friendly fluorescence detection method for captopril was established. It has been successfully used for captopril detection in captopril tablets.