A dual-functional Zn(II) metal-organic framework sensor for smartphone-assisted visual fluorescence detection of aniline and TMEDA in the vapor and aqueous medium.

Aniline and N,N,N',N'-tetramethylethylenediamine (TMEDA), as key intermediates in organic synthesis, are widely used in pharmaceuticals, pesticides, and other fields. However, the pollutants pose significant threats to human health and ecosystems. Rapid and selective quantification of trace amine compounds in environmental samples remains a highly challenging task. In this work, a novel Zn(II) metal-organic framework (MOF), namely [Zn3(BTBD)3(HNTB)3]n (JXUST-59, BTBD = 4,7-bis(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole, H3NTB = 4,4',4″-nitrilotribenzoic acid), was synthesized under solvothermal condition. JXUST-59 enables the bifunctional detection of aniline and TMEDA through fluorescence quenching, with detection limits as low as 1.096 and 3.476 μM, respectively. Notably, JXUST-59 represents the first MOF fluorescence sensor capable of detecting TMEDA. To expand the practical applicability, JXUST-59 was fabricated into fluorescent test strips for effective identification of aniline and TMEDA vapors, as well as into portable composite films for the detection of such amines in real water samples. Furthermore, a smartphone-based detection method was established and optimized, extending the application scope of the fluorescence sensor. Overall, this work not only demonstrates a feasible approach for the quantitative detection of amine vapors using JXUST-59 but also provides a detection strategy for trace amines in water samples, offering critical theoretical and technical support for the rational design of sensors.