Scientists have created a groundbreaking method to detect tiny amounts of hard-to-find explosives from more than eight feet away, eliminating the need to swipe clothing, luggage, or other materials.
This innovative approach, detailed in the journal Talanta, allows for the detection of trace explosives like nitroglycerin and RDX—the explosive in C-4—through the air at extremely low levels within seconds.
Explosive substances release very few molecules, making detection challenging.
However, the new technology is so sensitive that it can recognize the faintest trace of an explosive in an environment filled with common air molecules like nitrogen and oxygen.
The detection capability is astounding, identifying explosives at levels of less than 10 parts per quadrillion.
To put this into perspective, it’s like finding a single pine needle among all the pine trees in the state of Washington, or picking out a single coin from a stack of pennies taller than Mount Everest.
Researchers at the Department of Energy’s Pacific Northwest National Laboratory (PNNL) have been developing methods to detect explosive vapors for over a decade.
Previously, they could detect these substances from about half an inch away.
Now, their latest technology extends the detection range to between two and eight feet, depending on the material.
“Previously, we could detect these explosive materials at a distance of the width of your finger. Now, our technology reaches the length of your arm and beyond,” said Robert Ewing, the PNNL chemist leading the team.
This technology has been licensed to BaySpec Inc., a Silicon Valley company specializing in spectral sensing for various applications, including defense and security. BaySpec plans to launch a commercial product based on PNNL’s technology for detecting explosives and narcotics by 2025.
Many explosive materials are hard to detect because they have low vapor pressure—they don’t evaporate quickly. This contrasts with substances like gasoline, which evaporate quickly and are easy to detect.
Ewing’s team focused on low-vapor explosives such as nitroglycerin and RDX, successfully detecting them from several feet away.
In earlier research, they also detected other explosives like tetryl, PETN, and TNT, as well as drugs like fentanyl, cocaine, and methamphetamine.
The team believes their new method, known as standoff detection, can be used to identify additional explosives, drugs, and other chemical threats.
“We hope this technology can be deployed to keep people safe from explosive threats,” Ewing said.
A significant factor in improving the standoff detection distance is a powerful, handheld air sampler developed at the University of Washington.
This sampler draws in approximately 300 liters of air per minute, allowing scientists to collect enough air in just 5 to 10 seconds to detect materials with lower vapor pressure.
The collected air passes through a filter that captures the vapors, which are then delivered to an atmospheric flow tube and detected by a mass spectrometer.
The key to the sensitive detection is the approximately two-foot-long atmospheric flow tube, where molecules are ionized before reaching the mass spectrometer.
The length of this tube provides more time for the target molecules to be ionized, significantly increasing the sensitivity of detection.
With this advanced technology, the team can identify explosives at incredibly low levels, improving safety and security measures. The research builds on the team’s previous successes, including an R&D 100 Market Disruptor Award.
The team also participated in the Trace Explosives & Drug Detection Workshop in Ireland to discuss related work.
This work is part of a broad PNNL program focused on explosives detection, aiming to enhance safety and security by developing advanced detection technologies.
