Chinese scientists sniff out new cheap way to detect a sarin gas attack
Chip-like detector developed in Anhui province could be rolled out at low cost to raise the alarm in vulnerable public places like subways
It is 20 years since the sarin attack in Tokyo subway that left more than a dozen people dead and hundreds injured, but there has been no practical defence in public areas against the killer gas - until now.
A team of researchers in Hefei, Anhui province, said it had worked with the military to develop the world's most sensitive sarin detector which could be installed at low cost in subways and other public areas vulnerable to attack.
In less than a second, the detector can spot sarin gas molecules in the air in concentrations as low as six parts per billion, according research by the team in Chemical Communications, a journal published the Royal Society of Chemistry in London.
The researchers said the device could help cut causalities in a sarin attack by alerting authorities as soon as the gas was released, allowing them to evacuate the area before concentrations reached lethal levels.
In the Tokyo attack, victims died once exposed to 100 milligrams of sarin per cubic metre of air for two minutes, according to the US military.
The deadly dose was hundreds of thousands of times above the detector's trigger level.
The gas's chemical properties are similar to many harmless compounds such as ethanol, making it difficult to build a machine to detect leaks.
Instead, chemical plants have for decades used animals such rabbits to signal the chemical's presence.
The researchers, led by professor Cai Weiping and Duan Guotao with the Chinese Academy of Sciences' Institute of Solid State Physics in Hefei, found that sarin left a unique "fingerprint" when its gas molecules were heated to various temperatures.
Inspired by the find, they developed a chip-like detector with greater sensitivity that could be mass produced.
Many laboratories have developed similar sensors, but none have been manufactured in great numbers or deployed on a wide scale due to high costs. The main problem has been the need for expensive individual assembly for most high-performance gas detectors.
The new mainland-developed detector could be mass-produced like smartphone chips with fabrication technology developed by the team.
The researchers said in their paper that the technology was ready for "real industrial application". Scientists from the No3 Department at the Institute of Chemical Defence, a research unit of People's Liberation Army, also contributed.
The new chip will be adapted for use on the battlefield to detect an enemy attack.