Since the world of sensors is my growing area of interests, I came across an article from chemworld today which caught my attention. The research is based on a particular synthetic chemicals which have the ability to detect explosives such as TNT. Its main application is for military purposes. These polymer and fibre materials can be embedded into fabrics such as clothing so that soldiers at war can easily detect hazard in their environment.
The materials were designed by exploiting small molecules that can easily polymerise. The problem with many of these sensors is that they are only soluble in organic solvents, thus their own objective was to modify these small molecules by process of polymerizing monomers in way that they are balanced as hydrophilic and lipophilic so it dissolved both in water and organic solvents. The recognizable signal is due to the fact that Lewis bases, such as amines, alkoxy and hydroxyl groups generate highly coloured Meisenheimer complexes with TNT with a detectible limit of 1-3 µM.
Initial designs of such sensors comes at a price. Its slow response between 2-11 hours and the fact that sensitivity were tested at 60 oC are clear disadvantages for practical application where explosives have to be detected at ambient temperature. Their work is now on maximising and optimising these sensors.
The first thing I usually look at when I read such articles are the structures. While doing a bit of searching, I first came across the same strategy and methods from the same lab using but different types of monomers. It has sensitivity towards mercury (Hg(II)) either by colourimetric or fluorescent detection, detectable between the limit of 6- 10 mM range[1].
[1] J L Pablos et al, RSC. Adv. 2014, 4, 25562
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