As part of their jobs, Soldiers and first responders who perform sensitive site exploitations frequently enter areas containing unknown chemicals at varying toxic concentrations. The handheld detectors they use are susceptible to false alarms, may have a limit of detection higher than the amount present, and may not accurately identify the chemical class of compounds present.

If a Soldier is potentially exposed to a chemical warfare agent, even at sub-lethal amounts, it is a race against time to obtain samples and identify the agent, often in a background of dozens or even hundreds of other compounds. Sub-lethal amounts of agent could produce symptoms that can be misdiagnosed as common illnesses, so it is important to know what chemical warfare agents are involved in order to provide the correct medical countermeasure. The RDECOM C&B Center’s new method will improve accurate identification.

First, the wearable sampler clips on to a Soldier’s uniform and collects information about various substances that the Soldier may have been exposed to during a mission.

“The sampler collects almost everything it encounters,” said Bruce King, Ph.D., RDECOM C&B Center research chemist and project lead.

The samples collected will reflect the Soldier’s day-to-day movements. The sampler is sensitive enough to collect the residue of soap the Soldier showered with, and analysis of the sample can reveal data such as whether the Soldier has recently fueled or operated gas- or diesel-powered equipment, and whether the Soldier has been exposed to any chemical warfare agents.
Then, RDECOM C&B Center researchers use the LECO Corporation Pegasus GCxGC-High Resolution Time of Flight (HRTOF) system to analyze the data gathered in the sampler and accurately identify the chemical warfare agents.

“In order for us to be able to separate and identify potentially thousands of compounds in a single sample, we utilize multidimensional gas chromatography coupled to a high resolution time-of-flight mass spectrometer. The system provides the separation and spectral resolution to pull characteristic peaks apart for differential analysis unavailable in field deployable systems. GCxGC-HRTOF has the ability to perform targeted analysis of threat list compounds and precursors with the confidence that a high resolution mass spectrometer provides, in addition to untargeted analysis that could identify a link between clandestine labs, which is unparalleled,” said King.

The RDECOM C&B Center has already deployed several wearable samplers to Soldiers outside of the continental U.S., and researchers are working towards optimizing the samplers form factor. Additionally, RDECOM C&B Center researchers are using data collected from the deployed samplers to determine the most effective selection methods to analyze samples for early warning and attributions of waterborne chemical hazards. This research could lead to the ability to determine the source of chemical warfare agent release and identify global trends in the use of emerging threats.