Instant Visual Detection of Picogram Levels of Trinitrotoluene by Using Luminescent Metal-Organic Framework Gel-Coated Filter Paper

• Published in: Chemistry : a European journal Vol. 19; no. 49; pp. 16665 - 16671
• Main Authors: Lee, Ji Ha, Kang, Sunwoo, Lee, Jin Yong, Jaworski, Justyn, Jung, Jong Hwa
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 02.12.2013; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Subjects: Aqueous solutions; Chemistry; Chemistry, Multidisciplinary; Equipment Design; Explosive Agents - analysis; Explosives; Filtration - instrumentation; gels; Humans; Hydrogels; Hydrogels - chemistry; Limit of Detection; metal-organic frameworks; Models, Molecular; Organometallic Compounds - chemistry; Physical Sciences; Science & Technology; sensors; supramolecular chemistry; Trinitrotoluene - analysis; Zinc - chemistry; CHEMICAL SENSORS; AU NANOPARTICLES; explosives; POLYMER-FILMS; EXCITATION-ENERGY TRANSFER; metal-organic frameworks; sensors; CHEMOSENSORS; gels; PLASMON RESONANCE DETECTION; PI-ORGANOGELS; ELECTROCHEMICAL SENSOR; TNT; EMISSION; supramolecular chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201301507

There is an ongoing need for explosive detection strategies to uncover threats to human security including illegal transport and terrorist activities. The widespread military use of the explosive trinitrotoluene (TNT) for landmines poses another particular threat to human health in the form of contamination of the surrounding environment and groundwater. The detection of explosives, particularly at low picogram levels, by using a molecular sensor is seen as an important challenge. Herein, we report on the use of a fluorescent metal–organic framework hydrogel that exhibits a higher detection capability for TNT in the gel state compared with that in the solution state. A portable sensor prepared from filter paper coated by the hydrogel was able to detect TNT at the picogram level with a detection limit of 1.82 ppt (parts per trillon). Our results present a simple and new means to provide selective detection of TNT on a surface or in aqueous solution, as afforded by the unique molecular packing through the metal–organic framework structure in the gel formation and the associated photophysical properties. Furthermore, the rheological properties of the MOF‐based gel were similar to those of a typical hydrogel. Sense and sensitivity on paper: A fluorescent metal–organic framework hydrogel exhibits greater detection capability for TNT in the gel state compared with that in the solution state. A portable sensor prepared from filter paper coated by the hydrogel was able to detect TNT at the picogram level with a detection limit of 1.82 ppt (parts per trillon; see figure).