What's Inside an Airport Swab “Substances Detector”

When you go through airport security, sometimes they pull you aside and swab your clothes and luggage with a probe which gets put into a machine to see if you’re carrying something you shouldn’t. I don’t know whether the selection for this is random or based on whether you look dodgy, but it’s happened to me a number of times. What does that machine do, and what’s inside it? Being naturally cynical when it comes to airport security theatre, I’ve harboured suspicions it was all for show but, in fact, there’s a lot of stuff inside those machines, some of it radioactive. The technique used is ion mobility spectrometry, which allows very fast detection of specific substances for which the device is calibrated.

The unit disassembled here is a Smiths Detection Ionscan 400B, which is commonly seen in airports in Europe. It claims to detect explosives (PETN, TNT, nitroglycerin, RDX) and “narcotics” (heroin, cocaine, amphetamines) at the parts per billion level.


I get swabbed regularly because I can’t go through their scanner devise with my insulin pump. That means I get a pat-down and a swab of my hands after wiping them on my pump. It’s all mostly BS. If we ALL had “permission” to carry firearms onboard, the hijacking rate would drop to zero and we’d save a ton on all this fuss and noise.

Yes I believe screening for explosives is reasonable, but fairly easily accomplished without all the noise and stupidity. Plus modern micro explosives take so small an amount that you could easily bring the components onboard with no one the wiser. It takes maybe 3cc of each of 2 components mixed, plus an igniter to blow up an aircraft. Sort of like mixing epoxy.