Titanium metal-organic framework nanorods for highly sensitive nitroaromatic explosives detection and nanomolar sensing of Fe3+

Fe3+ is the fourth most important transition metal ion in biological systems. Also, nitro-aromatics is a class of compounds which is highly explosive and toxic. Therefore, selective detection of Fe3+ and nitro-aromatics is of great significance for human health and environmental protection. In this work, we reported a rare example of Ti-MOF material (ZSTU-1) for highly sensitive and selective luminescent sensing of nitroaromatic explosives and nanomolar level of detection of Fe3+. To the best of our konwledge, ZSTU-1 is the first report of Ti-MOFs for highly efficient sensing of nitroaromatic explosives, and realized excellent sensing properties for PA (2,4,6-trinitrophenol) in both liquid and vapor phase. In liquid, the detection limit for PA can reach 12.3 μM (2.8 ppm) and the Ksv is calculated to be 3.586 × 104 M−1. The most important is that there have been very few MOF-based sensors reach the nanomolar level of detection Fe3+ with the detection limit calculated to be 63.8 nM (approximately 3.6 ppb) and the Ksv value of ZSTU-1 nanorod is 2.69 × 106 M−1. In addition, the detection of Fe3+ and nitroaromatic explosives was carried out in fluorescent test paper which could be used for rapid detection of these substances by naked eyes. These results demonstrate the advantages of titanium-based MOFs for the detection of Fe3+ and nitroaromatic explosives, and can contribute to develop a high performance and visible to the naked eyes fluorescent sensor for detection of specific substances that are vital in biological systems.