A mini version of lab equipment that identifies chemicals in suspect substances could someday help perform on-the-ground testing for chemical warfare agents.
Collecting samples of sarin, VX or other nerve agents and shipping them to a lab for testing can take weeks, says Robert Williams, a physical organic chemist at Los Alamos National Laboratory in New Mexico. “If you can turn this into a portable system, you can make it a lot easier for people to use,” he says. “And you could get the results immediately.”
Williams and colleagues are building a nuclear magnetic resonance, or NMR, spectrometer to identify toxic chemicals without the big, heavy magnets of standard NMR systems (SN: 1/12/09). This technology could be used to test whether someone has deployed illegal chemical weapons, or to judge whether it’s safe to return to areas previously exposed to poisonous substances.
Williams’ team presented the work August 26 in San Diego at the American Chemical Society’s national meeting.
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NMR systems typically use strong magnetic fields to probe a quantum property of individual atomic nuclei called spin (SN: 2/7/18). Those measurements reveal where specific nuclei are in a compound, allowing scientists to discern its structure. But homing in on individual nuclei requires hefty magnets that generate fields thousands of times stronger than Earth’s magnetism.
The new system maps the molecular structure of a compound by probing magnetic interactions between the spins of adjacent nuclei in the compound. That technique requires a much weaker magnetic field of only about 50 microteslas — about as strong as Earth’s magnetism — and just a few drops of a sample.
In lab experiments, the superweak magnetic field device has recognized chemical cousins of hazardous materials, as well as breakdown products of nerve agents such as sarin and soman. “We will be looking at live [chemical warfare] agents soon,” Williams says.
Also on the agenda: downsizing the prototype — currently the size of a large suitcase — to be even more portable.