1 August 2002
Chemical detection muscle grows
Compared with bioagents, progress detecting chemical agents is much further along.
John Barnes, ABB vice president and general manager of analytical process analytics subcontracts, said the government is interested in a variation of ABB's Questor Mass Spectrometer. Built to monitor petrochemical and industrial processes, one instrument monitors up to 40 agents in real time, Barnes said.
Variation of this ABB
"The government is concerned about nerve gas, blister agents, blood agents, and we can detect all of those with our mass spectrometer," Barnes said. ABB's spec sheet says the analyzer detects gases or vapors with molecular weights ranging from 1 to 250 atomic mass units. Its lower detection limit is 10 parts per million with a Faraday detector or 10 parts per billion with a dual Faraday/multiplier detector.
Another ABB instrument, a Fourier transform infrared (FTIR) spectrometer, could detect chemical agents at considerable distances, he said. At first, ABB developed the FTIR instruments to monitor atmospheric pollution emissions at plastics, petroleum, chemical, and pharmaceutical plants.
Lawrence Livermore National Laboratories also developed a portable mass spectrometer it claims "provides laboratory quality analysis of complex simple matrices in the field" and prevents loss of samples that could deteriorate if transported to a remote lab. The 65-pound Gas Chromatograph-Quadrupole Mass Spectrometer can also be field serviced.
Scientists at the U.S. Department of Energy's Ames (Iowa) Laboratory and the University of Michigan (UoM) demonstrated a novel, fluorescence-based chemical sensor its developers claim is more compact, more versatile, and less expensive than previous technology.
Ames senior physicist Joseph Shinar said the sensor could monitor oxygen, inorganic gases, volatile organic compounds, biochemical compounds, and biological organisms. Potential applications include detecting pathogens and other warfare agents, point-of-care medical testing, and high-throughput drug discovery. The sensor grew out of basic UoM research studying photophysics of luminescent organic thin films and organic light-emitting devices, which luminesce when a voltage is applied.
"Integration and miniaturization of fluorescence-based chemical sensors is highly desirable. It is the first step toward the development of fluorescence-based sensor arrays that could be used for analysis of living cells and organisms and biochemical compounds," said Shinar.
Conventional sensors use lasers or inorganic light-emitting devices as light sources, but they present problems: Not only are they expensive, but they are also bulky and cannot integrate with other sensor components.
Finds buried explosives
A computer program developed at NASA's Jet Propulsion Laboratory in Pasadena, Calif., provides real-time sensor fusion and display capabilities for detecting buried mines and other explosives. Called U-Hunter, it finds buried, unexploded ordnance and explosive waste via magnetic and electromagnetic sensors. U-Hunter uses data from a variety of sensors, including magnetometers, synthetic aperture radar systems, and pulsed eddy current sensors. The software's data enhancement subsystem preprocesses and conditions input data for analysis and an analysis engine subsystem. A visualization subsystem generates displays showing geophysical data as 3-D surface models and 2-D color maps. Future U-Hunter developments include extending data display capabilities to produce data overlays, aerial photography, and geophysical data.