Macademics: Ion Mobility



Hey everyone! It's time for another addition of #Macademics! This month I wanted to tell you all about something I learned in one of my classes this semester because I thought the fun fact was cool.

So, have you ever wondered how those body scanners at the airport work? Well, they use ion mobility spectrometry (IMS) and are used to detect explosives and drugs on our bodies and that's what I'm going to talk about this week.

Ion mobility is an analytical technique that separates gas phase ions based on how they interact with an electric field in a matter of milliseconds. Each ion has a specific size, shape, and charge and will feel the force of an electric field differently. Smaller, more compact ions will leave the drift tube faster because they can move through the gas easier, while larger ions take longer due to being held up by the gas during there travel. The great thing about IMS is that it's fast, sensitive, and also portable - since it doesn't need large pumps or any special instrumentation - making trace detection of drugs and explosives really easy to do in an airport.

In a body scanner, or puffer machine, you stand in the chamber and experience a puff of air. That puff of air, transmits particles from your body and clothing and analyzes them through IMS for separation and detection. Every drug or explosive has a characteristic drift time and mass and if that is identified on your person, TSA gets notified... you all can guess what happens next.

IMS can also be coupled to mass spectrometry ! This coupling gives both a separation of the mixture of ions in a sample and also specific mass-to-charge (m/z) data. Knowing the drift time, m/z value, and even how the ions fragment (called tandem mass spectrometry, which we'll save for another time), all can help with the identification of the compounds in an unknown sample.

I hope you all enjoyed my fun fact for this month and I hope a few of you think about IMS the next time you're in an airport.

See you next month for another #Macademics post!

-The Chemist

#IonMobility #MacScientist #Macademics #Science #BlackChemist

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