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New Device Sniffs Out Black Powder Explosives

sciencehabit writes "The Boston marathon bombers Tamerlan and Dzhokhar Tsarnaev reportedly purchased several pounds of black powder explosive before the bombing. Used in fireworks and bullets, the explosive substance is both deadly and widely available. It's also very hard to detect. Now, researchers have modified one bomb-sniffing device to accurately spot very small amounts of black powder, an advance that could make us safer from future attacks. What has prevented detection of black powder by IMS in the past, however, is that sulfur and oxygen -- which composes 20% of air—hit the detector at almost the same time. A strong oxygen signal can thus mask a small amount of sulfur, like what a bombmaker's dirty fingers might leave on a luggage strap. A group led by chemist Haiyang Li at the Dalian Institute of Chemical Physics in China modified an IMS to eliminate the oxygen signal. 'We have tested the sensitivity of TR-IMS, and its limit of detection of black powder can reach as low as 0.05 nanograms,' Li says."

13 of 133 comments (clear)

  1. Did Anything Happen in West, Texas? by Anonymous Coward · · Score: 3, Insightful

    All I keep hearing about is knee jerk reactions to a sad but relatively trivial event in Boston.

  2. Re:or... by icebike · · Score: 4, Informative

    And tiny firecrackers, and the smoke there-of.
    Legal uses of black powder would easily swamp and overwhelm this detector. So in order to prevent false positives,
    expect a major crackdown on black powder. Vaseline too.

    Further, its never been hard to train dogs to sniff out black powder, so having a machine that does this is probably not much cheaper.

    --
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  3. Wow! by bogidu · · Score: 3, Insightful

    Bullets are made out of black powder? All the ones I've used have been made out of lead or copper. How do those black powder bullets hold together?

    Reporters, please learn the difference between:

    Ammunition and bullets
    Magazines and clips
    Automatic vs Semi-Automatic

    etc, when talking about firearms.

  4. More niggling by NoImNotNineVolt · · Score: 4, Informative

    I'd hate to come across as pedantic, but...

    An ammunition cartridge is composed primarily of:
    Bullet: The projectile that is ejected from the muzzle of the firearm at high speed.
    Propellant: The chemical explosive that is burned to propel the bullet.
    Primer: The component that chemically generates heat when struck with sufficient force, igniting the propellant.
    Casing: Just what it sounds like, the part that holds everything together.

    Now, to keep this from being entirely off-topic...
    Modern ammunition cartridges do not contain black powder. They contain smokeless powder. Much like "clips" and "magazines", or "diesel" and "gasoline", these are two different things that are not interchangeable.

    --
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    1. Re:More niggling by CrimsonAvenger · · Score: 4, Interesting

      Modern ammunition cartridges do not contain black powder [wikipedia.org]. They contain smokeless powder [wikipedia.org]. Much like "clips" and "magazines", or "diesel" and "gasoline", these are two different things that are not interchangeable.

      A slight quibble:

      blackpowder can be loaded into any casing and will work just fine (for certain values of fine - be VERY careful about loading). Note that the .45-70 cartridge was originally blackpowder, is now smokeless powder, but is the same size cartridge it always was, so can be loaded quite safely with 70 grains of black powder instead of whatever amount of smokeless it comes out of the box with.

      Note that the above quibble really only matters to the few of us who own replicas of the 1873 Springfield .45-70 cavalry carbine (7th Cavalry used them at Little Big Horn, for reference) and feel the incredible urge to foul the barrels of our carbines for a more "realistic feel"....

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
  5. Less than worthless by gweihir · · Score: 4, Informative

    Black powder can be found almost everywhere, even in societies that do not have a gun-fetish. Every little firecracker has it in it. These detectors would cause so many false positives as to be not only absolutely worthless, they would have negative value as they waste massive amounts of resources.

    But I get it, the US administration, and under its tutoring the US population, have lost all rationality when it comes to "terrorism" a long time ago. The next bombing (and it will happen) will just cause as much useless actionism and more steps towards a police-state as this one did. And if it takes too long for the next bombing to happen, the FBI will arrange a fake one, as they have done several times before.

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    1. Re:Less than worthless by CrimsonAvenger · · Score: 3, Insightful

      Black powder can be found almost everywhere, even in societies that do not have a gun-fetish.

      What does a "gun-fetish" have to do with it?

      Black powder isn't used in any commercial cartridges that I know of, and the overwhelming majority of gun owners don't own or use black powder for anything but their Fourth of July fireworks.

      It's mostly used by reenactors of various sorts, with muzzle-loading muskets/rifles/pistols/revolvers, and bought by the pound (I've got the best part of a pound in my ammo safe).

      Though, frankly, making it is not so difficult as all that.....

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
  6. false positives? by houghi · · Score: 4, Interesting

    This would be great to create false positives. Just sprinkle some on random people to create as many false positives as possible.
    Then when they turn the system off, do some small attack and then when they turn it back on, start with the false positives again.

    remember: terrorism isn't about killing people, it is about spreading terror. The actual limiting of peoples freedom will be done in congress. Installing this means the terrorists have won.

    --
    Don't fight for your country, if your country does not fight for you.
  7. Re:One small problem... by CrimsonAvenger · · Score: 4, Informative

    You're better off using modern replacements for actual black powder, since the corrosive effects of that old sulfer charcoal saltpeter stuff is pretty nasty over time.

    Which is why cleaning your blackpowder firearms THOROUGHLY immediately after use is mandatory.

    My Civil War era revolvers get disassembled and tossed into boiling water soon as I get home. For a start....

    --

    "I do not agree with what you say, but I will defend to the death your right to say it"
  8. Too much Hollywood by slew · · Score: 3

    What this appears to be talking about is how at the airport they now swab your carry-on luggage and put it in a machine. I don't think these boston folks would have been though any "swabing" checkpoint so the existance of a device that did this probably would not have made anyone "safer" in this case (or any similar non-airport/govt-building checkpoint situation).

    For those curious, the idea behind an IMS (ion mobility spectrometer), is that you ionize your sample (well sort of, you have water or other liquid vapor with ions dissolved in it, not just pure ions in air or in a vaccum) and waft them into a drift tube and use fact that these ionized vapors have slightly different masses so they have different mobility under an electric field. The "spectra" of the mobility under this electric field helps to identify the original chemicals in the swab.

    The specific problem they are trying to solve with black powder is that the ions formed by Sulphur (atomic mass 32) and Oxygen (atomic mass 16) are very difficult to disambiguate for a clean detection signal (since O2n- and S1n- have about the same mass).

    The common method of disamgibuating is to add solvents or chemical reagents before ionization. AFAIK, in the case of Oxygen interference, a common way to change the ionic signature is to add dichlorolmethane CH2CL2 and the resulting reaction usually exchanges O2- ions for CL- ions (which is enough different than sulphur ion to make it easy to detect), but unfortuantly, dichloromethane also has a side effect of inhibiting the formation of various Sulphur ion allotropes (i.e., different number of sulphur atoms in the ion). So these folks apparently came up with a technique where you ionize first (avoiding the problem with CH2CL2 and sulphur ion formation) and then pass all the ions through a CH2CL2 "titration region" in the drift tube (effectively replacing many of O2- ions that mask the sulphur ion signature with Cl- ions).

    Of course the devil is in the details which I haven't read about yet...

  9. Re: One small problem... by BetterSense · · Score: 3, Insightful

    You make my point for me. You DO NOT have to "qualified and liscenced" to have black powder. You DO NOT have to tell anyone (cops included) 'where you got it' anymore than you have to tell them where you bought your sneakers. What's the point in detecting something that is perfectly legal?

    It's sulphur, salpeter and charcoal.

  10. Black Powder? by Molochi · · Score: 4, Informative

    Just a side note because it's making me nerdrage :) TFA asserts "Used in fireworks and bullets, the explosive substance is both deadly and widely available." Assuming that they are actually talking about "black powder" I think this was an included invention by the writer.

    Manufactured ammunition (with a very few niche and very expensive exceptions) hasn't used "black powder" for its loads for over 100 years. Modern ammo uses "smokeless" powders with a variety of chemical compositions based around nitroglycerin and 1or 2 other nitro based chemicals. These should be easily detectable with existing sniffers that are looking for nitrates. So if a day on the range was going to get me hauled in at the TSA line, well were already past that.

    Pyrodex and other Black Powder substitutes are more commonly used by muzzleloader hunters and Pyrodex is "smokeless powder" based and formulated for the lower power of black powder explosions. I should also be easily detectable.

    Garden variety "buy it a supermarket go-bang fireworks" use perchlorate based fuel as far as I know. I don't know how detectable it is or how chemically similar it is to black powder off the top of my head. But I'd guess it's not and would prefer it to be detectable.

    On the other hand I CAN buy black powder by the 16oz can with cash. I think it would be good thing if the chemsniffers could detect it.

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  11. Pointless - there were already bomb-sniffing dogs by SuperBanana · · Score: 3, Interesting

    There were bomb-sniffing dogs working the marathon - they were pulled once the elite runners had gone through and the dignitaries had left.