Indian scientists have developed a cost-effective portable sensor that can trace explosives and toxic metals such as trinitrotoluene (TNT), trinitrophenol (TNP) and RDX even if just a few molecules are present, on the scale of parts per million (ppm). The senor, a solution, can be easily carried in public spaces like airports, railway and hotels or sensitive areas to counter terrorism.
Developed by Dr CV Yelamaggad, and his team from Bengaluru-based Centre for Nano and Soft Matter Sciences (CeNS), an autonomous institute under the Department of Science & Technology, the solution works on the simple visual detection technique.
Talking about the concept, Dr Yelamaggad, who has been working on the technique for last 3 years, said, "It employs a fluorescent material known as coordination polymer, a hybrid system originating from the interaction between organic and inorganic moieties. This system being electron rich acts as an electron source.
"The explosive materials containing nitro groups are electron deficient and act as electron sink," he said.
"A charge transfer complex or an association of 2 or more molecules is formed between these electron sources and sink that is non-fluorescent and hence the fluorescence intensity decreases drastically which can be observed visually. The sensing can be done in solution as well in thin film forms at very minute part per billion concentrations," he further explained.
Selectivity is very perfect. Currently, there are many different kits which are being used for the sensing of explosive materials but they suffer from major drawbacks such as large size, need of repeated calibration and so on. However, solution phase developed by Dr Yelamaggad and his team can be comfortably transported and used in various places such as airports, rail stations and shopping complexes owing to its compact size and ease of handling. The simple visual detection technique makes it compatible to be used without calibration. A prototype of the sensor has been fabricated and demonstrated in the Bengaluru INDIA NANO-2018 expo under a collaborative project with Tata Steel. " We are also trying to explore possibilities to detect other explosives such as acetonitrile, benzene and toluene etc," said Dr Yelamagged.Researchers said that with such low cost sensors they want society to be a much safer place to live. "This is not just a research but in keeping with the societal responsibilities. We still need to do a lot of investigation.If this development can help save a single life it would be a great win for me," summed up the scientist.
