ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Green-precursor carbon dots as effective “off” fluorescence sensors for detecting MnO₄⁻ ion in environmental water quality monitoring

Xuejiao Jing, Li Song, and Changxin Wu

Institute of Biomedical Sciences, Shanxi University, Taiyuan, China

E-mail: 953450953@qq.com

Received: 13 August 2024  Accepted: 22 February 2025

Abstract:

Developing carbon dots as a fluorescent probe specifically for detecting residual permanganate ion (MnO₄⁻ ion) in water is crucial for effective environmental water quality monitoring. In this study, nitrogen-doped carbon dots (N-CDs) were successfully synthesized using purslane as a green precursor and ortho-phenylenediamine (OPD) as a nitrogen source via a simple one-step hydrothermal method. These N-CDs exhibited a maximum emission wavelength of 486 nm when excited at 358 nm. They demonstrated significant antioxidative properties in various concentrations of H₂O₂ and showed high photostability and resistance to photobleaching under different pH, ionic strength, and UV irradiation conditions. Furthermore, the N-CDs were validated as highly selective and sensitive fluorescence sensors for MnO₄⁻ ion, demonstrating a linear relationship within the concentration range of 0.5–168 uM with a detection limit of 41.8 nM. The sensor successfully detected MnO₄⁻ ion in spiked tap and river waters, achieving satisfactory recovery.

Keywords: Carbon dots; Portulaca oleracea; Ortho-phenylenediamine; MnO4 − ion; Water quality monitoring

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-03982-0

Chemical Papers 79 (5) 2983–2993 (2025)