Solid-Phase Microextraction Techniques
Solid-phase microextraction (SPME) is a chemical technique designed to detect chemical compounds. In its forensic application, it is used to find chemical warfare agents, high explosives, or illegal drugs. Among the world's leading research institutes in forensic SPME work is Lawrence Livermore National Laboratory's Forensic Science Center (FSC) in San Francisco. Established in 1991, the FSC, which had 15 staff members in 2002, implements a variety of research tools in forensics. Among these is SPME, which makes use of optical fibers to collect chemical samples.
Extremely small, these fibers are about 100 micrometers thick—the width of a human hair. Stored in syringes, they are coated with chemicals made to respond to specific substances such as particular explosives or drugs. With a minimum of disruption and effort, these "chemical dipsticks" can collect thousands of compounds.
One of the few drawbacks of the fibers used in SPME is the fact that they are extremely fragile, and for this reason, the FSC developed durable aluminum storage tubes. They have also provided the Federal Bureau of Investigation with portable SPME field kits, as well as a transport tube small enough to fit in a shirt pocket. The FSC is licensing both versions to private industry for sale to the federal government.
SPME has been used at the FSC to monitor the safety of nuclear warheads as part of the Stockpile Stewardship Program. After collecting samples of volatile and semivolatile molecules formed from the breakdown of organic polymers and high explosives, scientists look for signs that corroded parts may need to be replaced.
█ FURTHER READING:
Bodrain, Rosemarie R. "Analysis of Exempt Paint Solvents by Gas Chromatography Using Solid-Phase Microextraction." JCT, Journal of Coatings Technology 72, no. 900 (January 2000): 69–74.
Comello, Vic. "Researchers Are Giving SPME a Second Look." Research & Development 41, no. 2 (February 1999): 44–45.
Marsili, Ray. "New Techniques Revolutionize Analyses of Liquid Samples." Research & Development 42, no. 2 (February 2000): 22–24.
Counterterrorism and Incident Response. Lawrence Livermore National Laboratory. < http://www.llnl.gov/nai/rdiv/rdiv.html > (April 2, 2003).
Solid-Phase Microextraction (SPME). Science & Technology, Lawrence Livermore National Laboratory. < http://www-cms.llnl.gov/s-t/solid_phase.html > (April 2, 2003).