Dogs have a very sensitive nose, which can smell minute amount of odor from explosive substances. This special ability makes dogs helpful in detecting explosives in the vicinity particularly when there are bomb threats.

Researchers, however, have been developing chemical and electronic equivalent of bomb sniffers that can similarly detect explosive molecules.

Steffen Bähring, from the University of Southern Denmark, and colleagues have developed one such material that can give warning once it detects molecules from explosives.

The new material is made up of a set of molecules that react when they encounter explosives. One of these molecules, the TNDCF, turns fluorescent once an explosive molecule is introduced. The set of molecules works in a way that the material lights up when it reacts to molecules from explosives.

This is not the first time that researchers have developed a chemical substance that can detect explosives. Past methods, however, are hounded by unreliability and problems such as the substance becoming fluorescent when no explosive molecule is detected in the vicinity and the fluorescence disappearing once the substance come into contact with molecules from explosives and some salts.

These limitations make the explosive-detecting substances unreliable. But the new material is different in that it works the other way around: it only lights up when it is exposed to explosive molecules and some specific salts including those that are based on chlorine and fluorine.

"The fluorescence emitting properties of TNDCF are quenched under conditions that promote the formation of supramolecular aggregates containing TTF-C[4]P and TNDCF. This quenching effect has been utilized as a probe for the detection of substrates in the form of anions (i.e., chloride) and nitroaromatic explosives," the researchers wrote in their study. "The addition of these substrates to mixtures of TTF-C[4]P and TNDCF produced a fluorescence 'turn-on' response."

The researchers said that this breakthrough may help improve security as such materials can be helpful particularly when there are bomb threats. It may even save lives.

"This new knowledge could lead to creating a small device based on this set of molecules. With such a device security staff in airports could e.g. test if there are explosives molecules on or near a bag," Bähring said.

The study, which was published in Chemistry - A European Journal on Dec. 2, also provides insight on molecules and atoms that constantly respond to their surroundings.

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