A fluorescent titanium-based metal-organic framework sensor for nitroaromatics and nanomolar Fe3+ detection

A fluorescent nanoscale titanium-based metal-organic framework materials (MOF), Ti6(μ3-O)6(μ2-OH)6(BTCA)2(DMF)2 (ZSTU-3) was synthesized, with blue fluorescence and delicate conjugated structures indicated its potential as a fluorescence sensor. In this work, we reported a rare example of Ti-MOF for highly sensitive and selective for fluorescence sensing of Fe3+ ion and nitro-aromatic compounds. The limit of detection (LOD) for Fe3+ ion reaches 70.7 ​nM and the Ksv value is 2.36 ​× ​105 ​M−1, which is among one of the highest LOD values reported by MOFs as far as we known. For the detection of nitro-aromatic compounds, especially 2,4,6-trinitrophenol (PA), the LOD is calculated to be 15.90 ​μM, and the Ksv value is 4.253 ​× ​104 ​M−1. In addition, we also performed a rapid detection of Fe3+ ion and nitro-aromatic compounds with fluorescent test paper by naked-eyes. The results demonstrate the superiority of Ti-MOF for detecting Fe3+ ion and nitro-aromatic compounds, which may facilitate the detection application in environmental and biological systems.