Nitrogen and Chlorine Co-Doped Carbon Dots with Yellow-Green Emission as a Ratiometric Fluorescent and Colorimetric Dual-Signal Probe for Quercetin Detection and Cell Imaging

Despite the emergence of numerous carbon dots (CDs)-based sensors, most of them are fluorescent probes. To improve the reliability of the results, using ratiometric fluorescence/UV-vis absorption dual-signal probes is an effective method. Herein, nitrogen and chlorine co-doped carbon dots (N, Cl-CDs) with yellow-green fluorescence were prepared and used as a dual-function probe for ratiometric fluorescence/UV-vis. The detection range of the fluorescence method was 0.05–78[Formula: see text][Formula: see text]M, and the limit of detection (LOD) was 1.2[Formula: see text]nM (3[Formula: see text]/s). For the colorimetric method, the linear range was 0.05–186[Formula: see text][Formula: see text]M with LOD of 10.7[Formula: see text]nM. Importantly, the N, Cl-CDs were successfully used to detect Quercetin (QT) in actual water samples. Besides, due to their good biocompatibility, the N, Cl-CDs were applied to in vivo biological imaging of oocysts and shown the potential for environmental survey and biological assay.