3D printed self-calibrating on-site sensing platform based on bimodal excitation carbon dots for visual 4-nitrophenol detection by means of the localization of inner filter effect and pH regulation

• Published in: Chemical engineering science 2023-11, Vol.281, p.119201, Article 119201
• Main Authors: Guo, Guoqiang, Zheng, Qi, Li, Tingting, Zhang, Ting, Tang, Siyuan, Li, Lintao, Gao, Sineng, Tang, Yan, Chen, Da
• Format: Article
• Language: English
• Subjects: 3D printed self-calibrating sensing platform; 4-NP; Bimodal excitation N-CDs; pH regulation; Ratiometric fluorescence strategy; The localized inner filter effect
• ISSN: 0009-2509
• DOI: 10.1016/j.ces.2023.119201

[Display omitted] •We synthesize a novel bimodal excitation N-CDs for ratiometric sensing of 4-NP.•Excitation-based ratiometric method has a low LOD of 0.083 µM from 0.083 to 80 µM.•A 3D printed self-calibrating sensing platform is designed for visual 4-NP detection.•We combine the as-designed device and smartphone to realize practical determination.•This work is conducive to the industrial production of consumer-friendly sensors. For facile and rapid detection of 4-nitrophenol (4-NP), we synthesize nitrogen-doped carbon dots (N-CDs) through microwave radiation treatment using melamine and o-phenylenediamine as precursors. We employed N-CDs as an ingenious ratiometric fluorescence sensor via a novel bimodal excitation behavior. As the concentration of N-CDs increases, the broad excitation peak splits into two excitation peaks. The blue-shift phenomenon appears at the short-wavelength excitation peak, while the long-wavelength excitation peak presents the red-shift. Consequently, 4-NP can be sensitively detected by N-CDs owing to the localization of inner filter effect (L-IFE) with the detection limit of 83 nM ranging from 0.083 to 80 µM. Moreover, a self-calibrating on-site sensing platform constructed by 3D printing technique realizes the visual 4-NP detection in actual samples based on bimodal excitation behavior and RGB analysis. Our work not only presents a novel perspective for visual 4-NP sensing, but also renders the integration of 3D printing technology and the CDs industry.