Using carbon nanotubes, MIT chemical engineers have built the most sensitive electronic detector yet for sensing deadly gases such as the nerve agent sarin, coupling the nanotubes with a miniature gas-chromatography column and separating different gases.
The technology, which could also detect mustard gas, ammonia and deadly VX nerve agents, has the potential to be used as a low-cost, low-energy device that could be carried in a pocket or deployed inside a building to monitor hazardous chemicals.
To build the super-sensitive detector, Professor Michael Strano and his team used an array of carbon nanotubes aligned across microelectrodes. Each tube consists of a single-layer lattice of carbon atoms, rolled into a long cylinder with a diameter of around 1/50,000 of the width of a human hair, which acts as a molecular wire.
Nanotube sensors require very little power, about 0.0003 watts and one sensor could run essentially forever on a regular battery. When a particular gas molecule binds to the carbon nanotube, the tube’s electrical conductivity changes and as each gas affects conductivity differently, so gases can be identified by measuring the conductivity change after binding.
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