Rapid and sensitive fluorescence sensing detection of nitroaromatic compounds in water samples based on pyrene functionalized nanofibers mat prepared via green approach

• Published in: Microchemical journal 2021-06, Vol.165, p.106175, Article 106175
• Main Authors: Cao, Jiankun, Zhang, Huayin, Liang, Sihui, Xu, Qian
• Format: Article
• Language: English
• Subjects: Deep eutectic solvents; Fluorescence sensing detection; Nanofibers mat fluorescent sensors; Nitroaromatic compounds; Water samples
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2021.106175

•Py-PAN NFM was prepared via a green approach based on deep eutectic solvents.•Py-PAN NFM was used for fluorescence sensing detection of TNT and DNT in real water.•Conversion of sample polarity was achieved by extracting water samples using CH2Cl2.•Conversion ensures targets directly interact with probes, increasing detection speed.•Conversion process can also enrich targets, thus improving sensing sensitivity. Pyrene functionalized polyacrylonitrile nanofibers mat (Py-PAN NFM) was prepared via a green approach based on deep eutectic solvents. The Py-PAN NFM was further employed as solid-state fluorescent sensors for determining 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) in real water samples. In order to adapt to the hydrophobicity of Py-PAN NFM surface, the water samples were extracted by dichloromethane, and then the extraction solvents were directly dropped onto the Py-PAN NFM. The conversion of sample polarity ensures that Py-PAN NFM does not need to be immersed in the water samples for a long time. The target TNT and DNT can immediately interact with the pyrene fluorophores on surface of Py-PAN NFM, thus accelerating the detection speed. Because the targets were also enriched through the conversion process, the sensing sensitivity has been significantly improved and the limits of detection of TNT and DNT can reach 8.81 × 10−9 M and 2.74 × 10−8 M, respectively. The Stern–Volmer plots for fluorescence quenching by TNT and DNT displayed an overall linearity in the entire tested concentration range with quenching constants of 2.57 × 106 M−1 and 3.15 × 105 M−1, respectively. Moreover, the selectivity study indicated that other nitro compounds have an insignificant effect on the fluorescence sensing detection of TNT and DNT, and Py-PAN NFM can be reused at least 6 times without degradation in fluorescence-quenching performance. The theoretical calculations demonstrated that photoinduced electron transfer was involved in the quenching process and the fluorescence lifetime measurements revealed that a static quenching mechanism was suitable to explain the quenching behavior. The experimental results fully proved the practicability of this method in the rapid and sensitive monitoring of nitroaromatic compounds.