Novel Zn/Co–N co-doped carbon quantum dot-based “on-off-on” fluorescent sensor for Fe(III) and ascorbic acid

• Published in: Talanta open 2023-08, Vol.7, p.100162, Article 100162
• Main Authors: Xu, Ouwen, Yang, Jing, Song, Hanyang, Dong, Luzheng, Xia, Ji, Zhu, Xiashi
• Format: Article
• Language: English
• Subjects: Ascorbic acid; Carbon quantum dots; Fe(III); Metal doped; “on-off-on” fluorescent probe
• ISSN: 2666-8319; 2666-8319
• DOI: 10.1016/j.talo.2022.100162

•Zn/Co-NCDs was synthesized by hydrothermal method.•Bismetal doping can protect the surface functional groups of CDs, thus effectively improving the fluorescence intensity of Zn/Co-NCDs.•Zn/Co-NCDs were used as a-"on-off-on" fluorescent probe to selective detection of 2 analytes.•Zn/Co-NCDs could be used for the determination of real samples with satisfactory results. In this work, the metal (Zn, Co) and non-metal (N) co doped carbon quantum dots (Zn/Co-NCDs) was prepared by hydrothermal method, and characterized by FT-IR, TEM and XPS. It was found that bimetal doped could effectively improve the quantum yield (QY) of carbon quantum dots. The presence of Fe(III) could "turn off" the fluorescence signal, and the addition of ascorbic acid (AA) could "turn on" the fluorescence signal. An "on-off-on" fluorescent probe based on Zn/ Co-NCDs for Fe(III) and AA analysis was established. The liner ranges were 0.03–20.00 μg/mL and 0.69–20.00 μg/mL with the LODs of 0.010 μg/mL and 0.23 μg/mL, respectively. The method was successfully applied to the determination real samples with satisfactory results. The TEM image is shown that the Zn/Co-NCDs are spherical particles with the particle size of 4–5 nm), and the average particle size is 4.7 nm. HRTEM images display that Zn/Co-NCDs have lattice stripes (0.23 nm), which can be attributed to the (100) in-plane lattice of graphene. [Display omitted]