Detecting explosives, not toothpaste

when it is exposed to the substance being analyzed.

“We tried to include specific molecules that would react with the peroxides,” Brotherton said.

Exposure to water also changes the polymer, but it returns to its previous state once the water is removed. Exposing the polymer to concentrated hydrogen peroxide, however, is irreversible.

“So once you’ve done this to the polymer you’ve permanently changed it,” Brotherton said. “Instead of being a reusable sensor, it’s more of a disposable dosimeter.”

It is also a detector that does not react to toothpaste and other common peroxide products, he said.

Detector has other potential uses
Manager Paul Smith said the sensor has other potential uses, such as monitoring underground water, looking for plumes of contamination, or monitoring industrial processes.

The sensor is not a silver bullet, but Brotherton said the technology has shown good results.

“It has some challenges that have to be overcome, but we think it’s worth pursuing to the next level,” he said.

Researchers need to reduce the chemical reaction time so the sensor doesn’t take too long to be useful at a checkpoint, he said. The detector also must be incorporated into a larger unit that includes equipment to gather a sample for analysis.

The sensor doesn’t need a significant amount of electronic processing or power supplies, Brotherton said. “This technology would be easier to integrate into other detection technologies without impacting them too significantly,” he said.

It would not have to be a large unit. Various detectors on the market today are about the size of a small, handheld vacuum cleaner, Smith said.

Getting air samples to the detector
The support equipment would suck up a sample of air and the detector would test it.

“You’d need to know where the fumes were coming from,” Brotherton said. “It’s not enough to open up the whole room and suck in all the air and say, ‘There are peroxides somewhere in here, watch out.’ What we’d like to do is go up and down luggage, or be next to some sort of industrial process so we know this is most likely the source and it’s above a level we care about.”

Although a detector package could target a single type of vapor, a manufacturer could add it to a unit that detects several substances. That way, a checkpoint could have one sensing system rather than separate units for every material of concern, Brotherton suggested.

“Maybe it’s a suite of sensors to try to hedge our bets,” he said. “We’ve focused on a very specific application, but there’s no reason you couldn’t take this concept and use different polymers and look at multiple substances at the same time.”