A smartphone-integrated dual-mode nanosensor based on novel green-fluorescent carbon quantum dots for rapid and highly selective detection of 2,4,6-trinitrophenol and pH

• Published in: Applied surface science 2019-10, Vol.492, p.550-557
• Main Authors: Fan, Yu Zhu, Tang, Qian, Liu, Shi Gang, Yang, Yu Zhu, Ju, Yan Jun, Xiao, Na, Luo, Hong Qun, Li, Nian Bing
• Format: Article
• Language: English
• Subjects: 2,4,6-Trinitrophenol; Carbon quantum dots; Colorimetry; Fluorescence; Smartphone
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.06.224

On-site monitoring of hazardous nitroaromatic explosive 2,4,6-trinitrophenol (TNP) is of great significance. In this work, we develop a bionic electronic eye-integrated dual-channel nanosensor to rapid and accurate quantification of TNP just via a smartphone. The sensing platform is composed of g-CQDs as the TNP-response recognition element and a smartphone as the optical signal detector, possessing simplicity, rapidness, and portability for TNP tracing. The transducer is based on novel green-emitting fluorescent carbon quantum dots (g-CQDs), which display color and fluorescence dual-signal response towards TNP. Under the optimum conditions, the color and fluorescence intensity change linearly with the increase of the TNP concentration in the range of 1.1–19.8 μM and 0.1–15.8 μM with a low detection limit of 0.4 μM and 27 nM, respectively. It is the inner filter effect that results in the sensitive fluorescence and color switch of CQDs by TNP. Also, the proposed sensor shows excellent selectivity towards TNP, because only TNP can compete for the excitation light with CQDs. Furthermore, the sensing platform is successfully employed to rapid, sensitive, and visual pH monitoring, fulfilling its bifunctional applications. Therefore, the smartphone-integrated dual-mode detection system is promising to be a new portable detector for on-site TNP and pH analysis. [Display omitted] •A smartphone-driven bi-mode nanosensor based on CQDs for TNP monitoring is built.•The visual colorimetric mode fulfills real-time TNP quantization via a smartphone.•The fluorescent mode shows rapidness, sensitivity, and high specificity to TNP.•The inner filter effect results in the sensitive fluorescence and color switch.•The design is expanded to rapid, sensitive, and visual dual-mode sensing of pH.