Indian Institute of Technology, Ropar (IIT Ropar) has developed a sensor that can detect even minute quantities of nitroaromatics — the organic chemicals used to make various explosives –including Trinitrotoluene (TNT). Since, it relies on chemical properties of nitroaromatics, the detector would be more accurate than sniffer dogs. Though effective, the method of scanning by sniffer dogs is not foolproof.
The institute has already developed these sensors in aqueous form and work is on to make it available in solid form “very soon”.
The research is being conducted in coordination with security agencies in India. The aqueous-sensors have already proven their effectiveness in tests by changing the colour of various bags, containers and another object in which the nitroaromatics were stored.
Aqueous sensor will also help monitor pollution
Numerous terror events worldwide have highlighted the need for highly sensitive and a portable explosive sensing device in a variety of environmental conditions.
The explosives prepared by using nitroaromatics remained challenging targets,” said associate professor at the chemistry department of IIT-Ropar Narinder Singh. It’s under his supervision that postdoctoral fellow Gagandeep Singh is conducting the research.
“We have prepared gold nanoaggregates derived from organic nanoparticles which are proven to be selective sensors for nitroaromatics including picric acid,” the faculty member points out.
“Picric acid is available in form of a powder and is a common constituent of many powerful explosives with a remarkable low detection limit. When the picric acid comes into contact with these nanoaggregates, there is a significant change in colour,” he says.
“To develop a selective, portable, fast, and sensitive method for detection of picric acid at very low concentrations was need of the hour. With the help of these sensors, it would be easy to avert terrorist threats as well as monitor environmental pollution,” he adds.
So far, aqueous sensor can also be used with the help of brushes. The brush dipped in aqueous-sensors will immediately change its colour from red to purple after coming in contact with any nitroaromatic.
It is a portable, sensitive and quick mode to trace nitroaromatics during frisking or checking at airports, railway stations or other such places.
The nitroaromatics are extensively used in industry for various purposes involving the synthesis of dyes, polymers, pesticides and pharmaceuticals.
Amongst the various nitroaromatics, picric acid has been exhaustively utilized by military powers for a long time in lethal weapons.
This acid poses an acute health risk due to its high solubility, and can easily contaminate soil and groundwater. Undetected traces have adverse health effects on all animals, including humans.