Pods of Science

How to Detect Explosives in Seconds

Episode Summary

Floppy-eared sniffer dogs made the news earlier this year as the latest change to security procedures in airports. But in the not-too-distant future, they could be replaced. The replacement is a technology that doesn't require a scratch behind the ear and a treat to its job.

Episode Notes

Jess Wisse (JW): What's behind the science and inventions that impact our daily lives? Pacific Northwest National Laboratory’s Pods of Science are the stories of what happens before the breakthrough. Before a technology becomes a house-hold name, before the life-saving drug his pharmacy shelves, before the paper's published - see what happens when great minds meet great challenges.

Music

Welcome. I’m your host, Jess Wisse. On today’s episode we’ll talking about new technology that may give dogs a run for their money. Wondering what we’re talking about? Stay tuned to learn more.

Music

JW: Floppy-eared sniffer dogs made the news earlier this year as the latest change to security procedures in airports. But in the not-too-distant future, they could be replaced. The replacement is a technology that doesn’t require a scratch behind the ear and a treat to its job.

Meet the man behind the tech: Robert Ewing.

Robert Ewing (RE): I like discovering things. I like solving puzzles. I like doing things that I don't think are possible, or challenging. And learning.

JW: Robert Ewing is a scientist at PNNL. And he’s made a discovery that could potentially save lives.

RE: I'm Robert Ewing. I'm a research chemist at the Pacific Northwest National Lab. I've been here for about 13 years. I've studied various analytical techniques for detecting trace of stances explosives and drugs, or some of those compounds. Ionization chemistry as a part of that. The instrumentation that goes along with that. Those are some of the things that I do for fun.

JW: So, what did Robert discover?

He and his team at PNNL developed a technology that’s ultrasensitive. It detects explosive vapors, deadly chemicals, and drugs like methamphetamine and fentanyl with unparalleled accuracy. And it works in seconds.

RE: The technology really stems from using the detector of a mass spectrometer. And that's a way to look at different molecules, to understand what mass is there. And from that you can sort of determine the analyte. Here you're looking at what we did, or one of the challenges, was is the ionization. So, for the mass spec to see a molecule you've got to put a charge on there so it can manipulate that charge, create an electric field, and separate it. And so the ionization process is a way of getting that charge, that electrical charge, onto an individual molecule. And that's really where I've spent a lot of my time—understanding the chemistry around how that ionization process works and how to improve upon it.

With the commercial mass specs that are out there that are pretty sensitive (parts per billion range and stuff) work pretty well. What we did is, we discovered that if you increase the amount of time that the ionization process can occur you can increase the sensitivity. And so the mass spec has a pinhole bringing the ions in from outside. What we do is, we took the ionization source and moved that away from the mass spec, and instead of having a few milliseconds of reaction time we give it two or three seconds and that gave us several orders of magnitude increase in sensitivity.

JW: This technology could be a game-changer for transportation hubs, mail facilities, and other safety and security screening applications, like the ones you see in airports.

Thanks to Robert’s tireless efforts, the system can detect a whole slew of things. Including explosive vapors, like TNT, toxic chemicals similar to nerve agents, and even illicit drugs, like fentanyl, methamphetamine, and cocaine.

The most surprising part? Robert thought this was a problem that was un-solvable. But he kept mulling on the idea, and that got him to think about none other than man’s best friend.

RE: Probably one of the driving force—the ah-hah moments—I always thought that explosive vapor was a challenge that we probably wouldn't overcome. And yet, dogs go out and sniff explosives all the time. Well, I've always wondered what dogs really smell? You know, are they smelling the explosive? Are they smelling the other things that surround that are that are higher vapor pressure, more volatile?

And I remember I went to a conference on explosives detection and they had a guy who had a detector dog and showed the detection of RDX. But he talked about his process of how he purified it, cleaned it, then trained his dog and showed it. And I watched it, you know, I watched the video. That dog has really seen. And I was like, “why can't we do that?” And so it was really about a month later when I was in the lab and said, “well, okay I got all the right tools.” I put it all together and on a Friday afternoon, I made it work. I mean so at some point it just happened.

JW: So how did Robert train this technology to sniff out specific vapors? The answer: Selective ionization chemistry.

RE: We talked about selective ionization chemistry. When you're detecting vapor at low parts per trillion parts per quadrillion levels there's a lot other things in the room. So we try to find selective ionization, so it's kind of like finding a needle in a haystack. You know how you do that? You use a magnet, right? The magnet is selective to the needle. It finds the metal and it ignores the straw. This is the same kind of thing. And that's where we spend a lot of our time is in that chemistry. Pick the right reactant ions, the ions that you want to has will analyze your analyte, and with that will analyze the materials we are looking for, and be kind of be invisible to the other species. So some examples there, you asked what chemicals we look at. You know explosives was one example. You want to see explosives, but maybe you don't want to see the various hydrocarbons and diesel fuel or gasoline or perfumes or colognes—things like that. And so that's the selectivity part.

JW: But for the longest time, detection of certain explosive vapors, like TNT, wasn’t possible. The instrumentation just wasn’t sensitive enough.

Typical instrumentation can see chemical levels in the parts per million and billion range. But many of the explosives out there in the world have very low vapor pressures—they’re more like in the low parts per trillion or below.

RE: So, an air you've got molecules and stuff floating around. They're always bumping into each other. I mean there's like 10 to the 11th collisions per second for a molecule, and air that's occurring. And so to bring those two together, you've got lots of lots of collisions that are probably going to occur. And so more time just gives you a higher probability that interactions going to happen.

JW: So now that we can detect things like explosives, what’s the future look like?

RE: So, one of the aspects of this this equipment. By being able to see vapor detection, that allows you to have non-contact detection. So, when you go through an airport nowadays, they usually swipe your bag and run it through an instrument looking for explosive residue. This ability to see vapor kind of helps remove that contact, so it's a little less invasive.

So, you can do maybe baggage screening or cargo screening, or you know even people when you walk through the imagers there to have a look for vapor at the same time. And so really, it's taking the next step of non-contact. Hopefully increasing screening speed, getting people through the airports quicker, and also maybe a little more thorough in your searches.

It's sort of that vision what we hope to do is be able to take this instrument and work with a smaller mass spec so then you can you get it in a footprint that's similar to stuff that's in the airport. Or you can integrate it to x-ray machines, or so forth. So, that's kind of what our hope is—to you know, take this to the next level. Get it into a smaller more portable size, and be able to test it and evaluate it, and see what other challenges need to be fixed.

JW: We asked Robert how it feels to know that he’s responsible for a technology that could potentially save lives. And he said, “it’s pretty cool.”

RE: It's challenging too because what we do doesn't happen overnight. I mean there every now then you have really good days and there's sometimes months where you struggle to get make things. So, it's a mix of, it takes a lot of determination to find those good breakthroughs.

JW: So, while it may not be in your local airport yet, PNNL’s vapor detection technology has a bright future. And that’s exciting.

[Music]

JW: Thanks for listening to Pods of Science. Want to learn more? Follow us on social media at PNNLab. We're on Twitter, Instagram, Facebook, and LinkedIn. You can also visit our website at pnnl.gov. Thanks for listening.

[Music]

Episode Transcription

Jess Wisse (JW): What's behind the science and inventions that impact our daily lives? Pacific Northwest National Laboratory’s Pods of Science are the stories of what happens before the breakthrough. Before a technology becomes a house-hold name, before the life-saving drug his pharmacy shelves, before the paper's published - see what happens when great minds meet great challenges.

Music

Welcome. I’m your host, Jess Wisse. On today’s episode we’ll talking about new technology that may give dogs a run for their money. Wondering what we’re talking about? Stay tuned to learn more.

Music

JW: Floppy-eared sniffer dogs made the news earlier this year as the latest change to security procedures in airports. But in the not-too-distant future, they could be replaced. The replacement is a technology that doesn’t require a scratch behind the ear and a treat to its job.

Meet the man behind the tech: Robert Ewing.

Robert Ewing (RE): I like discovering things. I like solving puzzles. I like doing things that I don't think are possible, or challenging. And learning.

JW: Robert Ewing is a scientist at PNNL. And he’s made a discovery that could potentially save lives.

RE: I'm Robert Ewing. I'm a research chemist at the Pacific Northwest National Lab. I've been here for about 13 years. I've studied various analytical techniques for detecting trace of stances explosives and drugs, or some of those compounds. Ionization chemistry as a part of that. The instrumentation that goes along with that. Those are some of the things that I do for fun.

JW: So, what did Robert discover?

He and his team at PNNL developed a technology that’s ultrasensitive. It detects explosive vapors, deadly chemicals, and drugs like methamphetamine and fentanyl with unparalleled accuracy. And it works in seconds.

RE: The technology really stems from using the detector of a mass spectrometer. And that's a way to look at different molecules, to understand what mass is there. And from that you can sort of determine the analyte. Here you're looking at what we did, or one of the challenges, was is the ionization. So, for the mass spec to see a molecule you've got to put a charge on there so it can manipulate that charge, create an electric field, and separate it. And so the ionization process is a way of getting that charge, that electrical charge, onto an individual molecule. And that's really where I've spent a lot of my time—understanding the chemistry around how that ionization process works and how to improve upon it.

With the commercial mass specs that are out there that are pretty sensitive (parts per billion range and stuff) work pretty well. What we did is, we discovered that if you increase the amount of time that the ionization process can occur you can increase the sensitivity. And so the mass spec has a pinhole bringing the ions in from outside. What we do is, we took the ionization source and moved that away from the mass spec, and instead of having a few milliseconds of reaction time we give it two or three seconds and that gave us several orders of magnitude increase in sensitivity.

JW: This technology could be a game-changer for transportation hubs, mail facilities, and other safety and security screening applications, like the ones you see in airports.

Thanks to Robert’s tireless efforts, the system can detect a whole slew of things. Including explosive vapors, like TNT, toxic chemicals similar to nerve agents, and even illicit drugs, like fentanyl, methamphetamine, and cocaine.

The most surprising part? Robert thought this was a problem that was un-solvable. But he kept mulling on the idea, and that got him to think about none other than man’s best friend.

RE: Probably one of the driving force—the ah-hah moments—I always thought that explosive vapor was a challenge that we probably wouldn't overcome. And yet, dogs go out and sniff explosives all the time. Well, I've always wondered what dogs really smell? You know, are they smelling the explosive? Are they smelling the other things that surround that are that are higher vapor pressure, more volatile?

And I remember I went to a conference on explosives detection and they had a guy who had a detector dog and showed the detection of RDX. But he talked about his process of how he purified it, cleaned it, then trained his dog and showed it. And I watched it, you know, I watched the video. That dog has really seen. And I was like, “why can't we do that?” And so it was really about a month later when I was in the lab and said, “well, okay I got all the right tools.” I put it all together and on a Friday afternoon, I made it work. I mean so at some point it just happened.

JW: So how did Robert train this technology to sniff out specific vapors? The answer: Selective ionization chemistry.

RE: We talked about selective ionization chemistry. When you're detecting vapor at low parts per trillion parts per quadrillion levels there's a lot other things in the room. So we try to find selective ionization, so it's kind of like finding a needle in a haystack. You know how you do that? You use a magnet, right? The magnet is selective to the needle. It finds the metal and it ignores the straw. This is the same kind of thing. And that's where we spend a lot of our time is in that chemistry. Pick the right reactant ions, the ions that you want to has will analyze your analyte, and with that will analyze the materials we are looking for, and be kind of be invisible to the other species. So some examples there, you asked what chemicals we look at. You know explosives was one example. You want to see explosives, but maybe you don't want to see the various hydrocarbons and diesel fuel or gasoline or perfumes or colognes—things like that. And so that's the selectivity part.

JW: But for the longest time, detection of certain explosive vapors, like TNT, wasn’t possible. The instrumentation just wasn’t sensitive enough.

Typical instrumentation can see chemical levels in the parts per million and billion range. But many of the explosives out there in the world have very low vapor pressures—they’re more like in the low parts per trillion or below.

RE: So, an air you've got molecules and stuff floating around. They're always bumping into each other. I mean there's like 10 to the 11th collisions per second for a molecule, and air that's occurring. And so to bring those two together, you've got lots of lots of collisions that are probably going to occur. And so more time just gives you a higher probability that interactions going to happen.

JW: So now that we can detect things like explosives, what’s the future look like?

RE: So, one of the aspects of this this equipment. By being able to see vapor detection, that allows you to have non-contact detection. So, when you go through an airport nowadays, they usually swipe your bag and run it through an instrument looking for explosive residue. This ability to see vapor kind of helps remove that contact, so it's a little less invasive.

So, you can do maybe baggage screening or cargo screening, or you know even people when you walk through the imagers there to have a look for vapor at the same time. And so really, it's taking the next step of non-contact. Hopefully increasing screening speed, getting people through the airports quicker, and also maybe a little more thorough in your searches.

It's sort of that vision what we hope to do is be able to take this instrument and work with a smaller mass spec so then you can you get it in a footprint that's similar to stuff that's in the airport. Or you can integrate it to x-ray machines, or so forth. So, that's kind of what our hope is—to you know, take this to the next level. Get it into a smaller more portable size, and be able to test it and evaluate it, and see what other challenges need to be fixed.

JW: We asked Robert how it feels to know that he’s responsible for a technology that could potentially save lives. And he said, “it’s pretty cool.”

RE: It's challenging too because what we do doesn't happen overnight. I mean there every now then you have really good days and there's sometimes months where you struggle to get make things. So, it's a mix of, it takes a lot of determination to find those good breakthroughs.

JW: So, while it may not be in your local airport yet, PNNL’s vapor detection technology has a bright future. And that’s exciting.

[Music]

JW: Thanks for listening to Pods of Science. Want to learn more? Follow us on social media at PNNLab. We're on Twitter, Instagram, Facebook, and LinkedIn. You can also visit our website at pnnl.gov. Thanks for listening.

[Music]