Featured Research

from universities, journals, and other organizations

UCSD Chemists Develop Portable Nerve Gas Sensor

Date:
August 22, 2000
Source:
University Of California, San Diego
Summary:
Using a silicon chip and parts from an inexpensive CD player, chemists at the University of California, San Diego have developed a portable nerve-gas sensor capable of detecting "G-type" nerve agents, such as sarin, soman and GF.

Using a silicon chip and parts from an inexpensive CD player, chemists at the University of California, San Diego have developed a portable nerve-gas sensor capable of detecting "G-type" nerve agents, such as sarin, soman and GF.

The achievement should eventually permit the development of a large number of small and inexpensive sensors that could be deployed by soldiers across a battlefield or by police after a terrorist explosion to rapidly detect the presence of certain nerve agents and to track the movements of the deadly plumes.

"With multiple sensors that have a radio transmitter attached to them, you can tell how big the cloud is and where it is moving and relay that information to a base station," says Michael J. Sailor, a professor of chemistry and biochemistry at UCSD. He will provide details of his group’s achievements today at the 220th national meeting of the American Chemical Society in Washington, DC.

The innovative silicon sensor was constructed by a team that included William C. Trogler, a professor of chemistry and biochemistry, and postdoctoral associates Sonia Letant and Honglae Sohn. It works by selectively detecting compounds with a phosphorus-fluorine chemical bond, such as sarin, at very low concentrations.

To accomplish this, the scientists used a catalyst that Trogler and his co-workers had developed for the Army to detoxify materials containing nerve agents and other deadly chemicals with phosphorus-fluorine bonds. This catalyst breaks the phosphorus-fluorine bond in "G"-type nerve agents, resulting in the production of hydrogen fluoride, which is used commercially to etch and frost glass.

The sensor detects the presence of hydrogen fluoride through a silicon interferometer—a stamp-sized silicon wafer, similar to a computer chip, with an optical coating containing the catalyst. The rainbow-colored optical coating, which is akin to the sheen left by a thin film of oil on water, changes color when molecules of hydrogen fluoride hit its surface. "These silicon interferometers can detect very, very small changes in color," says Sailor.

The key to their sensitive detection is the use of a small laser, similar to that found in CD players, which measures the small changes in intensity of light reflecting from the optical coating on the surface of the silicon chip. "It turns out that if you take a laser that’s at the right frequency that matches the properties of that layer, you can measure very small amounts of chemicals as they enter the coating," says Sailor.

While the diode laser that the UCSD scientists built for their sensor is a bit more sophisticated than those in inexpensive CD players, it can be reproduced cheaply. In fact, the researchers’ first sensors were constructed from five inexpensive CD players they purchased at Fry’s, a local electronics discounter. "Our program manager at the Defense Advanced Projects Research Agency, which sponsored our research, raised an eyebrow when I told him that story," says Sailor. "But for 24 bucks, we got an interferometer that was sensitive enough to detect chemicals in the parts per billion range."

The low-cost feature of the UCSD design should make it possible to deploy handfuls of sensors in a terrorist nerve-gas attack, like the 1995 Tokyo subway bombing, in which sarin was used. Because the laser is capable of recording the accumulation of hydrogen fluoride molecules on the silicon chip’s surface, the sensor can also be used as a dosimeter. "You can tell how much nerve gas an area has been exposed to," says Sailor.

He says the main advantage of the sensor is that it is more specific to the detection of G-type nerve agents than the surface acoustic-wave devices, which are currently used to detect nerve gas, but which tend to produce an excess of false alarms.

"The advantage of this new development is that we’ll be able to reduce the false-alarm rate," adds Sailor, whose team published the technical details of their development in a recent issue of the Journal of the American Chemical Society. "The disadvantage is that we’re specific to only one type of nerve agent."

Although the UCSD researchers have not tested their sensor on nerve gas, they have demonstrated that it can detect a compound called diisopropylfluorophosphonate, or DFP, which is structurally related to sarin and soman, at a level of 800 parts per million. They plan to test the UCSD sensor on live nerve gas at an Army research laboratory later this year.


Story Source:

The above story is based on materials provided by University Of California, San Diego. Note: Materials may be edited for content and length.


Cite This Page:

University Of California, San Diego. "UCSD Chemists Develop Portable Nerve Gas Sensor." ScienceDaily. ScienceDaily, 22 August 2000. <www.sciencedaily.com/releases/2000/08/000822082130.htm>.
University Of California, San Diego. (2000, August 22). UCSD Chemists Develop Portable Nerve Gas Sensor. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2000/08/000822082130.htm
University Of California, San Diego. "UCSD Chemists Develop Portable Nerve Gas Sensor." ScienceDaily. www.sciencedaily.com/releases/2000/08/000822082130.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
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:
from the past week

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