June 11, 2009

Devices for detecting Toxins

Electrical Engineers Develop Microplasma Device to Detect Toxins

Electrical engineers have developed a new, portable lab that identifies chemicals by their unique color signatures. It is the first such device to be portable, allowing scientists to recognize potentially deadly chemicals right on the scene of crime, terrorist attacks, or industrial accidents.

Jeffrey Hopwood, an electrical engineer at Plasma Science and Engineering at Northeastern University in Boston, invented a portable microplasma device to detect deadly toxins in the air. He says,
"So when I hold this to the fluorescent light, you can see mercury in the spectrum and the plasma source is only about the size of a human hair."

This portable microplasma device is extraordinary because of its size. It can be taken anywhere. It uses a spectrometer to measure the unique set of colors or wavelengths emitted by dangerous chemicals. "Any time you excite a sample gas it will emit a unique signature of color or wavelengths," Hopwood says.

Depending on the color, researchers can determine the type and amount of contamination. For example, sulfur dioxide is released from burning coal and causes acid rain. The device would give off a blue-green color, indicating sulfur.

The device is lightweight and cheaper than all the other detection devices. Currently desktop-size machines tests for contaminants but samples cannot be analyzed on scene.
The microplasma device is currently used for industrial purposes.

Northeastern University researchers have built a portable, cell-phone-sized device that can quickly detect tiny amounts of contaminants in the air from natural disasters, industrial accidents, or terrorist attacks. Slated to become commercially available in the next year, the device uses some of the same technology used in cell phones and plasma televisions to create a smaller, cheaper, and lighter portable unit for performing chemical analysis, instead of bulky lab equipment requiring thousands of watts of power.

HOW IT WORKS: The microplasma device converts samples taken from the air into very small plasmas and then measures the unique set of light colors (wavelengths) that are subsequently emitted by the electrically charged atoms and molecules. A cell-phone chip supplies the radio-wave energy needed to create the microplasma. Instead of beaming those radio waves to the outside world, that energy is concentrated inside the unit, in a microscopic gap -- about one-half the width of a human hair -- within a thin ring of gold. All that energy in so small an area causes the collected gases in the gap to become what scientists call 'ionized': the electrons are stripped from the gas atoms. The device watches the light emission from the plasma to determine if there are any contaminants in the air. It can do this because every chemical element has a distinct "signature" in the form of what kind of light it will emit under those circumstances.
The Institute of Electrical and Electronics Engineers, Inc and AVS -- the Science and Technology Society contributed to the information contained in the TV portion of this report.

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