Sensor that can sniff out explosives in battlefields
doi:10.1038/nindia.2019.96 Published online 23 July 2019
A sensor that can detect minute traces of explosive chemicals — thereby helping protect civilians and military personnel in battlefields — has been devised by scientists at Indian Institute of Technology in Roorkee and the Indian Institute of Science Education and Research in Kolkata.
The polymer-based light-emitting sensor can sniff out explosives in solution and vapour phases.
Besides being harmful for human life, explosive chemicals such as trinitrophenol, widely used to make burn ointment, dyes, glass and leather-based products also contaminate the soil and aquatic systems.
Existing techniques for detecting such explosives are complex and time-consuming. To devise a simple and effective method, the scientists, led by Soumitra Satapathi, produced a sensor using specific polymers and dansyl chloride. They then exposed the sensor to various concentrations of explosive chemicals such as trinitrotoluene (TNT), trinitrophenol (TNP) and dinitrotoluene (DNT) in organic solutions in the presence of light.
Increasing the concentrations of the chemicals reduced the sensor’s light-emitting intensity. The sensor detected TNP more selectively than TNT and DNT. When converted to a thin film, the sensor was able to detect the chemicals in a vapour phase.
It displayed no change in light emission when exposed to chemicals such as acetonitrile, benzene and toluene, suggesting that it is sensitive and selective only towards TNT, DNT and TNP.
The thin-film sensor, when integrated with other electronic devices, could sniff out explosives in buried landmines. It could also monitor pollutants in soil, groundwater and seawater.
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