BRA DLEY R . HA RT/LLNL
SCIENCE & TECHNOLOGY
FINDING WEAPONS Forensic Science Center scientists tackle a number of CHEMICAL CHALLENGES JYLLIAN KEMSLEY, C&EN WEST COAST NEWS BUREAU
drugs in cadavers, or finding new ways to detect chemical or explosive agents, chemistry is central to much of its work. FSC’s most important role is perhaps its ability to handle chemical weapons samples for OPCW. As part of that effort, FSC participates in annual tests when the OPCW labs are checked on their ability to identify not only key chemical weapons agents but also the agents’ raw materials, precursors, and decomposition products. Not counting enantiomers, the labs must be on the lookout for about 12,000 potentially dangerous chemicals. Missing as few as two or three chemicals present in the test samples can result in an OPCW lab’s certification being suspended pending the next round of tests. Reporting merely one false positive results in a lab losing its certification entirely. FSC Director Dennis J. Reutter, who served as a Department of Defense representative in The Hague when the CWC was implemented, notes that “when we set the rules, we set the bar very high.” The results of chemical weapons inspections can, after all, lead to economic sanctions or military action against a country. The samples, prepared by another OPCW lab, are designed to be difficult to analyze. They LL NL
WHEN THE CHEMICAL Weapons Convention (CWC) was ratified in 1997 to destroy existing stockpiles of weapons and prevent the production of new ones, the Organisation for the Prohibition of Chemical Weapons (OPCW) was established to oversee implementation of the treaty. As part of OPCW’s mission, it sends inspectors to countries to check for CWC compliance. It also certifies laboratories around the world to analyze samples obtained by inspectors. The Forensic Science Center (FSC) at Lawrence Livermore National Laboratory (LLNL), in California, is one of 16 labs worldwide—and one of two in the U.S., the other being the Army’s Edgewood Chemical Biological Center, in Maryland— currently certified by OPCW to analyze chemical weapons samples. FSC is also the only lab in the U.S. that can handle forensic samples relating to the full range of threats—chemical, biological, radiological, nuclear, and explosive—collectively known under the term weapons of mass destruction (WMD). The center’s dozen staff members use world-class instrumentation—some of which is only available on-site at LLNL—to tackle some of the nation’s most difficult forensic science problems. They participate in current investigations of criminal or terrorist events and in research and development efforts aimed at preventing incidents. And whether FSC is analyzing chemical weapons samples, identifying
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can take the form of ON ALERT A set of microscale liquids or emulsions, cantilevers bend or chemicals can be in response to spiked into media chemical binding, such as soil samples. providing a fingerprint to Diesel fuel and other identify warfare substances are often agents. added to make analysis more difficult. The labs get 15 calendar days to analyze the samples by whatever means they have available. At FSC that typically means various combinations of elemental analysis, nuclear magnetic resonance, liquid chromatography, and various gas chromatography (GC) techniques such as GC-mass spectrometry (GC/MS), GC/ MS-chemical ionization, GC/MS-electron impact, or GC-infrared spectroscopy. Often, chemical intuition comes into play. In the last testing round, in late 2007, one chemical came up that the scientists
weren’t sure about, “but it looked kind of suspect,” FSC chemist Armando Alcaraz says. FSC chemical information specialist Amal Moulik eventually found a literature reference to the compound as a precursor to an agent similar to the nerve toxin tabun. In another case, FSC scientists spent a week identifying a compound that had an elemental composition similar to a VX-type nerve agent. In the end, they determined that it was just a red herring spiked into the sample to challenge the analysts. MAINTAINING A LAB with the personnel
and equipment to do high-level, diverse, and potentially classified chemical weapons work that could be used to inform national security decisions—and keep it all available on a moment’s notice—is an expensive task. Adding to the challenge is that although FSC is located at LLNL and uses some of the facility’s equipment and expertise, it does not receive any of LLNL’s Department of Energy (DOE) funding for operations and maintenance because forensics is not part of DOE’s mission. Instead, FSC is paid by the job. “I’ve made the analogy that it’s a bit like running a firehouse and being paid per fire,” Reutter says. “It’s a challenging business model.” OPCW-specific work is funded by DOE’s Office of Dismantlement & Transparency. To
DETECTOR The ELITE
card shows a colorimetric response to TNT.
ELITE card, swipes it on the suspect surfurther maintain its resources, the center face, and then puts the tab back into the takes on projects from various agencies card. The officer then breaks one of two that advance national security goals withglass vials, releasing a nucleophile that out being directly related to an investigareacts with the phenyl group of trinitrotion. The agencies the center works with toluene (TNT) or similar materials to form include the Department of Homeland a complex that creates an intense color on Security, the Federal Bureau of Investigathe card. tion, the Food & Drug Administration, and the Environmental Protection Agency. O For example, FSC is working O on an EPA contract to identify S P S what happens when a chemical N O P S N or biological weapon is released inside a building. Does the CH3 agent degrade? How does it or its degradation products interact with the materials inside THIS IS A TEST During an annual lab review, the facility, and what can be FSC’s elemental analysis indicated an unknown cleaned up or what needs to be compound (left) might be similar to VX (right), destroyed? The resulting inforbut further examination showed it to be benign. mation should help EPA with its mission to clean up after any If the TNT test is negative, the officer WMD incidents. can then break the second vial to release The results of these studies can also a reagent that reacts with organic nitrite guide sample collection for forensics compounds to form a pink diazonium dye. analysis to identify the perpetrator in the This part of the test could detect military event of a WMD attack, Reutter notes, in explosives such as RDX or HMX, as well that if you know where the agent goes, then as ammonium nitrate and pentaerythritol you know where to sample. “It doesn’t do tetranitrate, one of the ingredients in the a lot of good to look for chemical agents on plastic explosive Semtex. As first respondthe face of stainless steel, since stainless ers “the users don’t care what kind of exsteel doesn’t collect them, but chair upholplosives there are, just that they’re there,” stery made from polyurethane acts like a LLNL scientist and former FSC Director sponge,” he adds. John G. Reynolds says. So having a simple FSC is also developing new ways to system with a color change to give a posidetect WMD. The result of one of those tive result is key, he says, as is having the projects, done with a research grant from unit be small and self-contained. Field FoDOE’s National Nuclear Security Adminrensics, in St. Petersburg, Fla., licensed the istration, is the Easy Livermore Inspection technology and brought the devices to the Test for Explosives (ELITE), a palm-sized commercial market in late 2007. device that can detect more than 30 differUnder a separate DOE contract, FSC ent explosives. has also developed a chemical vapor sensor ELITE is designed to be quick and easy that can detect a variety of chemical subto use: A first responder such as a police stances, including agents such as VX and or military officer removes a tab from the WWW.C E N- ONLI NE .ORG
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I N V ESTI GATI O N
FSC Provided Vital Link To Serial Killer guilty in 2002 for administering lethal doses of the muscle relaxant pancuronium (Pavulon) to patients when he worked as a respiratory therapist at hospitals in Los Angeles. O The investigation O of Saldivar CH3 began in H + N+ 1998, when N a suspicious H H H3C coworker O notified the H police that O an unusual Pancuronium number of deaths were occurring during Saldiinternational security var’s shifts. Police collectdecisions. But the center ed much circumstantial also analyzes samples for evidence but were unable investigations closer to to make a direct link behome. One investigation tween drugs in Saldivar’s FSC worked on was the possession and the dead case of Los Angeles-area patients. In May 1999, serial killer Efren Saldivar, the Los Angeles County a respiratory therapist coroner exhumed bodies known as the “Angel of for autopsy. FSC then took Death.” Saldivar pleaded At the Forensic Science Center (FSC) at Lawrence Livermore National Laboratory (LLNL), most chemical analyses aim to inform national or even
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up the task of trying to detect one of the drugs accessible to Saldivar, pancuronium, in samples of tissue, gravesite soil, and water from the caskets. The samples came from patients who had died in 1996 and 1997. Several were extensively decomposed; some also contained embalming fluids, dyes, and formaldehyde. FSC chemist Armando Alcaraz, along with Brian D. Andresen and Patrick M. Grant at FSC, developed a method for extracting the drug from tissue by homogenizing samples with buffer, passing the buffer solution through a solidphase extraction polymer, and finally eluting compounds from the polymer using various solvents (J. Forensic. Sci. 2005, 50, 196 and 215). They spiked pancuronium into pig liver to use as control samples—using
voluted by a commustard gas. The O puter program. sensor unit is comCl O The sensor is posed of an array of CH3 O P Cl designed to be a microcantilevers— O P N Cl “set it and forget it” “little silicon diving O CH3 device that could boards,” says FSC CN be placed to moniscientist Bradley R. tor buildings or Hart, who led the pipelines. It has low project—that are SUSPICIOUS STRUCTURE power needs and each coated with a FSC analysts’ radar went up when no consumables different polymer they determined the structure of an to be replaced. (Analyst 2008, 133, unfamiliar compound (left), which The group is now 608). The polymers turned out to be a possible precursor working to adapt are not selective for to a nerve agent similar to tabun (right). the technology to individual chemidetect analytes cals but rather react with low volatility such as pesticides, FSC differently with individual compounds. postdoc Albert Loui says. As part of that When the polymers react, they cause the effort, the researchers are looking at coatcantilever to bend, which changes the elecing the cantilevers with high-surface-area trical resistance. The overall pattern leads materials such as functionalized aerogels to a fingerprint of sorts for an individual or metal nanoparticles in a polymer matrix chemical; complex mixtures can be deconWWW.C E N- ONLI NE .ORG
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JACQUELINE MCBRIDE/LLNL
SCIENCE & TECHNOLOGY
ON THE ROAD FSC chemist Richard E. Whipple prepares a glove box for use inside FSC’s
mobile response van, which travels to assist nearby investigations. thing, even your clothes,” Alcaraz recalls. Using gas chromatography-mass spectrometry, as well as high-performance liquid chromatography coupled to a tandem, triple-quadrupole mass spectrometer with an elec-
trospray ionization source, the team was able to identify pancuronium in six of the exhumed bodies. The results eventually led Saldivar to agree to a plea bargain in which he received six life sentences without the possibility of parole.
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both fresh tissue and samples that were aged for several weeks in a fume hood. Between the exhumed samples and the pig livers, the lab wasn’t exactly a pleasant place to be. “Even working in hoods the odor got into every-
that would be capable of picking up very low concentrations of material. Although FSC has separate funding and projects from its neighbor labs at LLNL, FSC’s placement within the facility gives it ready access to resources that can be key to WMD forensics. In particular, the knowledge of the nuclear weapons staff comes to bear during analysis of the origin of a nuclear or radiological device. LLNL also has significant systems modeling expertise such that “if you can imagine a device, you can predict how it will behave and what its impact will be in a number of different environments,” Reutter says. Additionally, FSC worked with LLNL’s Energetic Materials Center on the ELITE project, whereas LLNL’s Center for Accelerator Mass Spectrometry offers FSC staff the opportunity to do extremely precise radionuclear dating on very small samples. Ultimately, Reutter hopes, the value in FSC will not be so much about identifying WMD, finding terrorists, or helping to clean up after incidents as it will be about deterring attacks in the first place. “That’s certainly what I think is most important about having a robust forensics capability for WMD” at FSC, he says. “You can’t think that you can do something and be anonymous about it. We will know how the material was made and what starting products were used. Working with law enforcement investigators, it is possible to find out where the material was made and by whom. To some groups, that will be a significant deterrent.” ■
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