ABERDEEN PROVING GROUND, Md. -- A team of U.S. Army Edgewood Chemical Biological Center, or ECBC, scientists is developing two new methods of detecting the presence of chemical and biological agent, one by using just a drop of liquid on a piece of filter paper and the other by using a pump to draw an air sample through paper.
The technology is called paper spray, which the team is developing in collaboration with Indiana University-Purdue University in Indianapolis, Ind.
The first method detects indications of human exposure to a chemical agent in any liquid, such as blood or urine, by placing a drop onto a piece of standard laboratory-grade filter paper. The paper is housed inside a plastic cartridge for easy transport and the cartridge is then inserted into a mass spectrometer to be analyzed. This research is published in the highly prestigious scientific journal, Analyst, and recently received top honors for being the journal's most downloaded research article of 2017.
Once fully developed, a Soldier only needs to place the disposable plastic cartridge in a pocket. Samples stored on the paper are stable at room temperature, even biological samples, and no further sample preparation is required for analysis. Once in the laboratory and inserted into an autosampler, a charge of electricity is applied to the paper which turns the sample into droplets that a mass spectrometer can analyze for the presence of agent.
Unlike other analytical methods, the Soldier taking the sample need not know anything about the type of threat. The paper spray results are ready in 60 seconds or less once inserted into a mass spectrometer. The ECBC research team even developed a form of paper that can analyze large biological molecules, thus allowing for this technique to also be used to detect protein toxin threats.
A limitation to quickly fielding this method as a fast, all-hazards, easy-to-use detection technology is the mass spectrometer. Currently, analytical grade mass spectrometers average 300 to 500 pounds, they are delicate and they are typically operated out of a brick and mortar or mobile laboratory, which could be many miles away from the Soldier and the point of sampling.
"One of the goals is to develop a ruggedized, miniaturized, man-portable mass spectrometer, ideally weighing no more than twenty pounds that is amenable to the paper spray technique," said Trevor Glaros, Ph.D., who leads the research team. "It can easily travel with the Soldier's unit and perform analysis at the sampling location."
The other avenue of research is described in an article the team published in Analytical Chemistry, the most-cited chemical journal in the world. This method detects chemical and biological threats in the air. The current method for chemical threats uses the Depot Area Air Monitoring System, or DAAMS. It is an older technology that relies on glass tubes and can take as long as six to twenty-four hours to provide results for ultra-low levels of agent. It is also too large and cumbersome for use on the battlefield.
The method Glaros and his team are developing uses a miniature pump to draw air through the same paper used in the liquid method. "It takes only two minutes to draw a sample and another minute to analyze, providing near real-time monitoring," said Elizabeth Dhummakupt, Ph.D., another member of the team. "Also, it can detect chemical agents below levels deemed safe for long-term, chronic exposure."
Currently all the work performed by the team has been done using one-off prototypes of the cartridge that holds the paper tickets. They plan to work with ECBC's Additive Manufacturing team using 3D printing to perfect its design and to develop a cover to protect the paper ticket containing the sample as it is carried around in a pocket.
Also, just as with the liquid technique, this approach needs to have a rugged, miniaturized mass spectrometer nearby to avoid losing time transporting the cartridge to a distant stationary laboratory.
Since all the work has been performed using analytical grade instrumentation, the research team also needs to test their detection systems on commercially available miniaturized mass spectrometer systems. Finally, they need to make sure the data generated is interoperable with the Army's larger command and control communications platform.
The articles Glaros and his team published can be viewed at: http://pubs.rsc.org/en/Content/ArticleLanding/2017/AN/C7AN00144D#!divAbstract and https://pubs.acs.org/doi/full/10.1021/acs.analchem.7b02530.
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The Edgewood Chemical Biological Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to provide innovative research, development and engineering to produce capabilities that provide decisive overmatch to the Army against the complexities of the current and future operating environments in support of the joint warfighter and the nation. RDECOM is a major subordinate command of the U.S. Army Materiel Command.
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