Featured Research

from universities, journals, and other organizations

Portable And Precise Gas Sensor Could Monitor Pollution And Detect Disease

Date:
September 21, 2009
Source:
Princeton University, Engineering School
Summary:
Researchers have demonstrated a method for identifying nitric oxide gas using lasers and sensors that are inexpensive, compact and highly sensitive. Such a portable device could be of great value to atmospheric science, pollution control, biology and medicine.

Gerard Wysocki, an electrical engineer at Princeton, worked with colleagues at Rice to develop a highly portable and sensitive method for detecting nitric oxide gas, a key player in pollution and human physiology.

In the air, it is a serious pollutant. In the body, it plays a role in heart rate, blood flow, nerve signals and immune function.

Nitric oxide, a gas well known to scientists for its myriad functions, has proven challenging to measure accurately outside the laboratory. A team of Princeton and Rice University researchers has demonstrated a new method of identifying the gas using lasers and sensors that are inexpensive, compact and highly sensitive. Such a portable device, suitable for large-scale deployment, could be of great value to atmospheric science, pollution control, biology and medicine.

Nitric oxide is so potent that a few molecules of it per billion, or even trillion, molecules of air promote smog, acid rain and depletion of the ozone layer. Similarly tiny amounts in a patient's breath could help diagnose asthma and other disorders.

The researchers believe their device could find uses ranging from the study and control of car and truck emissions to monitoring human exposure to pollutants in urban and industrial environments. For medical uses the device is particularly attractive because the results are not corrupted by water vapor, which is present in breath samples. Testing for nitric oxide in a patient's breath, for example, could reveal chronic obstructive pulmonary disease and inflammation.

"The sensor we've developed is much more accurate and sensitive than existing systems, yet is far more compact and portable," said Gerard Wysocki, assistant professor of electrical engineering at Princeton.

Wysocki is a co-leader of a team that developed the system and conducted preliminary tests during the 2008 Olympic Games in Beijing. The team included Rice researchers Frank Tittel and 1996 Nobel laureate Robert Curl, both pioneers in the field of molecular detection using lasers, as well as Rafał Lewicki and James Doty III, also of Rice. The team published its results in the Aug. 4 issue of the Proceedings of the National Academy of Sciences.

With improvements made after the Beijing test, the system could be made into a portable, shoe-box-sized device ideally suited for mass deployment in large-scale unattended sensor networks for global, real-time, continuous monitoring of nitric oxide and other gases present in trace amounts.

Existing systems to detect nitric oxide and other trace gases have a variety of drawbacks. Some, such as carbon monoxide sensors for homes, are compact and inexpensive, but not very sensitive. These sensors can at best detect gases at parts-per-million concentrations -- they can't handle the parts-per-billion level, let alone the parts-per-trillion level that some applications require. High-end systems, such as mass spectrometers and gas chromatographs, are much more sensitive, but are slow, bulky, complicated and expensive -- and impractical for use outside of a lab.

Of intermediate sensitivity are optical systems that pass a laser beam through a gas sample and detect whether some of the laser light is absorbed by the gas sample. A weakness of this method is that the amount of absorption is very small compared to the overall amount of laser light, so the signal is hard to detect. Further, conventional optical sensors tend to be bulky, use large amounts of the sample, and require frequent operator intervention.

The new system developed by Princeton and Rice researchers uses optical sensing as well, but produces a much stronger signal. In their setup, the researchers passed the laser light through polarizing filters that block all light unless nitric oxide is present. Roughly speaking, the more nitric oxide, the more light makes it through the filters, Wysocki said. "There's no background signal to worry about."

Nitric oxide detectors have used similar methods before, but until now have been hampered by their reliance on large laser sources designed for laboratory use, he said. The new system, in contrast, uses a quantum cascade laser, a state-of-the-art device ideally suited for this sensing technique. This makes it possible to reliably detect the gas at a concentration of a few parts-per-billion. The device is so precise it can distinguish between different isotopes of nitrogen and oxygen in the nitric oxide molecules.

"It's remarkable we have that kind of sensitivity," said Curl, who laid the groundwork for the detection technique in a paper he co-wrote with Tittel nearly 30 years ago.

"A portable sensor that can continuously measure nitric oxide with such high sensitivity is a real breakthrough," said Tittel.

Unlike other systems that need several liters of the sample gas, the new sensor needs only a few milliliters of it, inside a container just about 16 inches long and a half inch in diameter. This frugality is particularly important in delicate biological applications such as cell-culture studies, said Wysocki. Also important, the new system can run much longer without intervention -- several hours compared to just a few minutes for even the best existing ones -- which will allow for long-term unattended operation.

Princeton researchers are working on various enhancements to the technology, further shrinking the size of the device and exploring an even more sensitive method of analysis called coherent detection. "This technique could help us achieve parts-per-trillion sensitivity," Wysocki said.

The work was supported by the National Science Foundation through a larger grant to the MIRTHE (Mid-InfraRed Technologies for Health and the Environment Engineering) Research Center based at Princeton, and by the Department of Energy as part of larger grants from Aerodyne Research Inc. and the Robert Welch Foundation.


Story Source:

The above story is based on materials provided by Princeton University, Engineering School. Note: Materials may be edited for content and length.


Cite This Page:

Princeton University, Engineering School. "Portable And Precise Gas Sensor Could Monitor Pollution And Detect Disease." ScienceDaily. ScienceDaily, 21 September 2009. <www.sciencedaily.com/releases/2009/09/090918153111.htm>.
Princeton University, Engineering School. (2009, September 21). Portable And Precise Gas Sensor Could Monitor Pollution And Detect Disease. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2009/09/090918153111.htm
Princeton University, Engineering School. "Portable And Precise Gas Sensor Could Monitor Pollution And Detect Disease." ScienceDaily. www.sciencedaily.com/releases/2009/09/090918153111.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) — Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins