William Trogler and his team at the University of California, San Diego, made a silafluorene-fluorene copolymer to identify nitrogen-containing explosives. It is the first of its kind to act as a switchable sensor with picogram (10-15g) detection limits, and is reported in the Royal Society of Chemistry’s Journal of Materials Chemistry.
Trogler's polymer can detect explosives at much lower levels than existing systems because it detects particles instead of explosive vapours. In the team’s new method one simply sprays the polymer solution over the test area, let it dry, and shine UV light on it. Spots of explosive quench the fluorescent polymer and turn blue – this makes it quick and visually exciting enough to be featured on the hit US TV programme CSI: Miami.
The polymer is able to show the difference between nitrate esters, such as trinitroglycerin, and nitroaromatic explosives, such as TNT.
Initially, polymer-treated spots of both compounds appear blue under UV light, but after further exposure the trinitroglycerin spot fluoresces green-yellow whilst the TNT spot remains blue. This colour change is thought to be due to photooxidation of the fluorenyl groups of the polymer.
Trogler was surprised to find that adding a spirofluorene co-monomer gave the polymer a 100 per cent efficient conversion of UV light into fluorescence, describing this increase as dramatic. 'From a technology perspective, the most surprising thing was the ability to use photochemistry to attain a reasonably chemospecific turn-on sensor,' he says.
The technology is now being commercially produced by RedXDefense, a security company based in the US.
The team are currently working on a similar system to detect peroxide-based explosives and say they hope to be able to investigate perchlorates and organic nitrates too.
Jon Edwards | alfa
Nesting aids make agricultural fields attractive for bees
20.07.2017 | Julius-Maximilians-Universität Würzburg
The Kitchen Sponge – Breeding Ground for Germs
20.07.2017 | Hochschule Furtwangen
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
19.07.2017 | Event News
12.07.2017 | Event News
12.07.2017 | Event News
20.07.2017 | Information Technology
20.07.2017 | Materials Sciences
20.07.2017 | Physics and Astronomy