ORNL Review: Mass Spectrometer Can Detect Weapons of Mass Destruction

Mass Spectrometer Can Detect Weapons of Mass Destruction

Editor's note: The following article describes an ORNL technology development that won an R&D 100 Award in 2000. The awards are presented annually by R&D Magazine in recognition of the year's most significant technological innovations. ORNL's 107 R&D 100 awards place it first among DOE laboratories and second only to General Electric.

A reconnaissance soldier drives a humvee through a field in enemy territory. His companion pushes a button on the display unit of a computerized instrument. Both soldiers are wearing protective gear. Their goal is to map out the area to determine which routes are safe for U.S. troops and which ones should be avoided. Eventually an alarm sounds. "Nerve gas VX has been detected," the soldier says to the driver, while checking the instrument. "We'd better take a different route." The soldiers drop warning markers and head in a new direction. An hour later, an alarm sounds again. This time the instrument has sniffed out another nearby threat: a cloud of anthrax spores. "Let's try another way," the driver says.

This scenario may play out in two or three years in a combat zone where soldiers will be able to use a vehicle-mounted Block II chemical biological mass spectrometer (CBMS), developed by ORNL and several partners. The CBMS, which received an R&D 100 Award in 2000, can detect both biological and chemical warfare agents in the midst of pollen; mold spores; engine exhaust; and fumes from fuels, lubricants, and fires, which would confound most detectors.

The CBMS can detect a biological warfare agent in about 5 minutes, much faster than the almost 15 minutes required by its nearest competitor. But it is unique in other ways, too.

"The CBMS is the only integrated system that can detect and identify chemical agents on the ground and in the air and biological agents in the air," says Wayne Griest, principal investigator for ORNL's project to develop the CBMS. "Compared with separate detectors, it is lighter, smaller, less power-intensive, and able to detect and identify more agents with improved sensitivity and reliability. It is tolerant to radiation, less expensive to use, and easier for soldiers to operate and maintain."

Roosevelt Meriweather and Rob Smith check the operation of the chemical biological mass spectrometer developed partly by ORNL researchers for use in helping U.S. Army soldiers detect the presence of biological and chemical warfare weapons.
(Photo by Curtis Boles.)

The heart of the Block II CBMS is an ion trap mass spectrometer. It is an outgrowth of the ORNL-developed direct sampling ion trap mass spectrometer successfully deployed to identify and measure hazardous chemical pollutants in the field. Vapors of chemical warfare agents (e.g., the nerve agent VX or blister agent HD) are drawn through a capillary line and routed to the ion trap analyzer cell by a sampling mode valve and open-split capillary interface. There, they are converted to ions by the chemical ionization reagent gas. The agents are identified from their unique product ions, which are split off from the parent ions in tandem mass spectrometry (MS/MS).

To detect biological warfare agents such as anthrax spores or bacterial toxins, the CBMS bio-concentrator samples air and concentrates micron-sized respirable aerosol particles. These are heated and reacted with a derivatizing reagent that produces fatty acid esters and other biomarker molecules characteristic of a hazardous organism, toxin, or virus. The ratios of the detected biomarker molecules indicate the presence of a particular biological agent. In the spectrometer, the biomarker molecules are ionized and analyzed using MS/MS.

Sophisticated algorithms are being developed to identify biological agents present in a background that may also include naturally occurring microorganisms, pollen, mold, and fungus. These algorithms determine whether the biomarker ions detected by the CBMS in the field match those characteristic of each suspected biological warfare agent. A library of these spectra is being built through experiments at ORNL's Chem-Bio Facility.

The Block II CBMS Program Team includes ORNL, Orbital Sciences Corporation, MSP Corporation, and the Colorado School of Mines. Collaborators include Dugway Proving Ground, White Sands Missile Range, and the Armed Forces Institute of Pathology. The sponsor is the U.S. Army Soldier and Biological Chemical Command.

In the fourth year of the project, Orbital Sciences Corporation has built six pre-production CBMS units. The team has plans to build additional units in the next year. Over the next two years, the team will be adding new capabilities to the units to meet new Army requirements. By 2003, a large number of rugged CBMS units will be produced for use on the battlefield.

"The 35 people at ORNL who have worked with me say that the CBMS project has been the most technically demanding of their careers," Griest says. As a result of the challenge, several innovations have come out of ORNL and the rest of the team. And the project has been especially rewarding because the prize-winning detector should save many soldiers' lives.

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