Materials

Device detects harmful gases in a matter of seconds

Device detects harmful gases i...
A Raman laser shines on a special chip, which traps gas molecules
A Raman laser shines on a special chip, which traps gas molecules
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Assoc. Prof. Ling Xing Yi (right) with PhD student Phan Quang Gia Chuong, operating the gas analyzer laser device
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Assoc. Prof. Ling Xing Yi (right) with PhD student Phan Quang Gia Chuong, operating the gas analyzer laser device
A Raman laser shines on a special chip, which traps gas molecules
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A Raman laser shines on a special chip, which traps gas molecules
Assoc. Prof. Ling Xing Yi (left) and PhD student Phan Quang Gia Chuong, with the specially-designed chip
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Assoc. Prof. Ling Xing Yi (left) and PhD student Phan Quang Gia Chuong, with the specially-designed chip

Ordinarily, if it's suspected that toxic airborne chemicals may be present in a given area, the analysis process can take up to several days. Now, however, scientists have developed a device that they claim can analyze the air on-location – but from a safe distance – within 10 seconds.

The tool was created by a team at Singapore's Nanyang Technological University, led by Assoc. Prof. Ling Xing Yi.

She was inspired by a 2017 event in which people in various parts of the country complained of a strong gas-like odor. It wasn't identified until days later as being caused by volatile organic compounds, produced by factories. Such a lag is actually not uncommon, as the typically-used Gas Chromatography - Mass Spectrometry air-analysis process involves first manually collecting air samples, with the actual lab-based analysis then taking anywhere from a few hours to a few days.

Instead, the new device incorporates a chip made of a porous metal-organic framework nanomaterial, which traps gas molecules that are in the area. A laser is then shone onto that chip, producing a lower-energy form of light as it interacts with the gas molecules. When that light is analyzed by a camera, its unique spectroscopic signature is compared to those of known toxic gases, allowing users to determine if any of those gases are present nearby.

Assoc. Prof. Ling Xing Yi (right) with PhD student Phan Quang Gia Chuong, operating the gas analyzer laser device
Assoc. Prof. Ling Xing Yi (right) with PhD student Phan Quang Gia Chuong, operating the gas analyzer laser device

The process is known as Raman spectroscopy, and it's typically been limited to the testing of solids and liquids, as airborne chemicals are usually too diluted for it to detect. That's where the nanomaterial comes in, as it not only absorbs gas molecules, but its metal nanoparticles also boost the light that is produced around those molecules, producing an easily-readable signal.

And as an added bonus, the laser and camera used in the procedure can currently be located up to 10 meters (33 ft) from the chip, and that distance could be increased in future versions. Alternatively, the chip could be used to collect gas molecules in potentially hazardous areas, and then be subsequently analyzed in the safety of a lab.

The university is now in the process of commercializing the technology. A paper on the research was recently published in the journal ACS Nano.

Source: Nanyang Technological University

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Expanded Viewpoint
The unit could be deployed on a small robot and the data gathered relayed via a cable or RF signal several hundred feet away, if a directional antenna is used. If a cell phone is used, the data could be sent anywhere in the world.