Audrey Martin adjusts the lens stack of the Single-Particle Aerosol Mass Spectrometry (SPAMS) system.

An All-in-One Detection Device

June / July 2007 By: Stephen Wampler Volume 5 Number 3

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Airplane passengers and baggage might be screened one day by a machine under development at Lawrence Livermore National Laboratory that can detect explosive, chemical, biological and narcotic agents—€”all at the same time. A team of researchers has conceptually proven that a four-in-one machine, or "universal point detection system," can be achieved, said George Farquar, a postdoctoral fellow and physical chemist at the lab's Glenn T. Seaborg Institute.

So far this year, the team has demonstrated that it can use its mass spectrometry system to detect the presence of minuscule particles of explosives and also to detect whether narcotics are present.

"We have found we can potentially detect an incredibly small quantity of explosives, as small as one dust-speck-sized particle weighing one trillionth of a gram, on an individual's clothing or baggage," Farquar said. "This is important because if a person handles explosives they are likely to have some remaining residue."

Using a system they call Single-Particle Aerosol Mass Spectrometry, or SPAMS, the Livermore scientists already have developed and tested the technology for detecting chemical and biological agents. The new research expands SPAMS' capabilities to include types of explosives that have been used worldwide in improvised explosive devices and other terrorist attacks.

"SPAMS is a sensitive, specific, potential option for airport and baggage screening," Farquar said. "The ability of the SPAMS technology to determine the identity of a single particle could be a valuable asset when the target analyte is dangerous in small quantities or has no legal reason for being present in an environment."

The team conducted its explosives tests under laboratory conditions last summer. "The tests went well. They show the potential to identify explosives in a field setting," Farquar said.

Most recently, in April, Livermore researchers developed the capability to detect over-the-counter medications and, potentially narcotics, with the use of the SPAMS system. In their experiment, the researchers used six different medications—€”aspirin, ibuprofen, pseudoephedrine, phenylephrine, loratadine and diphenhydramine. They placed individual pills of the medications in small glass vials, shook the vials, and then sampled the air above the vial with the SPAMS instrument.

"We were able to measure distinctive molecular markers that were indicative of the medications in under 10 seconds," Farquar said. "All six medications were easily identifiable just by looking at the data."

While over-the-counter medications were used in the April experiments, Farquar and his colleagues anticipate that the SPAMS technology would work equally well for illicit narcotics. It also may help in other ways. For example, pseudoephedrine is a precursor for methamphetamines. A person carrying a large quantity of pseudoephedrine might in some cases be involved in the manufacture of illegal drugs.

It is envisioned that the SPAMS system may have other applications for the pharmaceutical industry, such as providing quality control assistance during manufacturing and verifying that imported drugs are genuine, not counterfeit.
Another possible use that the Livermore researchers plan to investigate is the forensic application of SPAMS in the event of a "dirty bomb" explosion. "The rapid identification of isotopes from the explosion could help determine the source of the radioactive material and assist in tracking down the perpetrators of such an act," Farquar said.

Additionally, SPAMS could one day be employed for environmental monitoring. The system could rapidly identify particulate matter to assess the risks of pollution, as well as perform long-term monitoring to see how the environment is changing over time.

Besides Farquar, other LLNL researchers on the explosives and narcotics detection teams included Audrey Martin, an LLNL chemist and Michigan State University Ph.D. student, as well as chemists Eric Gard and David Fergenson, and physicist Matthias Frank.

The early history of the four-in-one detection system started at LLNL in 1999 with the development of the Bioaerosol Mass Spectrometry (BAMS) system. This system can detect airborne biological pathogens and sound a warning in less than one minute. In 2005, the technology was recognized with an R&D 100 award as one of the top industrial inventions worldwide.

In late 2005, Livermore researchers started work to expand the capabilities of BAMS to include chemicals and explosives, setting the stage for the new machine now called SPAMS. In that same year, with support from the laboratory directed research and development program, work started to explore the use of BAMS for biomedical diagnostics. This effort has produced promising results in that area.

"While this instrument started as a biological detector, we saw that it had the potential to do much more by detecting other threat agents, such as chemicals and explosives," Farquar said. The biological detection system underwent field testing for background studies at San Francisco International Airport in late 2005. Farquar describes the biological detection technology "as very solid."
In late 2005, the biological system underwent testing for several biological "surrogates" at the Applied Physics Laboratory at Johns Hopkins University. A second round of tests—€”with smaller releases and seven days of autonomous sampling—€”was conducted in April.

Plans for SPAMS include a major field test later this year at a public facility in the United States and upgrading the technology for removing particles from luggage and clothing, Farquar said.

Stephen Wampler is a communications specialist at Lawrence Livermore National Laboratory.