A new portable device may soon give homeland protection teams a better sense of chemical dangers. The tool makes it possible for the first time to perform nuclear magnetic resonance spectroscopy in the field on samples of any size.

“NMR is a unique and powerful tool for chemical characterization as it penetrates deep within nonmetallic objects,” says Vasiliki Demas, a University of California at Berkeley chemical engineering graduate student who co-authored a paper on portable NMR device, which appeared in the April 8 issue of Science.

This instrument, developed in collaboration by researchers at the Lawrence Berkeley National Laboratory, the UC-Berkeley, and the Institute for Technical Chemistry and Macromolecular Chemistry in Aachen, Germany, would be capable of achieving NMR spectral resolution with a palm-size, open-configuration probing head, important considerations to security officials on the front line.

Conventional NMR requires costly magnets and invasive procedures, as samples must be placed inside a small magnet bore. A portable “ex-situ” NMR sensor alleviates such restrictions, however, offering open access to arbitrary-sized samples and allowing NMR for non-invasive applications such as detecting concealed explosives, Demas says.

“Our device does not compete with the superconducting magnets that are used to study proteins, but there are many applications, including homeland security, where you can't bring samples from the field to the laboratory,” she says.

Over the past 50 years NMR spectroscopy has become the preeminent technique for determining the physical, chemical and biological properties of matter. It is the only spectroscopic method for which a complete analysis and interpretation of the entire spectrum is normally expected.

Until recently, high-resolution NMR spectroscopy could be done only by placing a sample inside the bore of a very large stationary magnet that produces a strong, uniform magnetic field.