Mass Spectrometry: How to Weigh an Atom

Parsing Particles

One of the problems scientists face in their analysis of Stardust samples is the sub-microscopic scale at which their work must be conducted. At the MagLab, FSU’s Humayun responded to this challenge with his innovative design for a mass spectrometer.

Mass spectrometers, in a nutshell, are machines that give scientists a look at the composition and origin of a material by analyzing and quantifying its atoms and molecules. They do this by vaporizing the sample (if it’s not already a gas) to make it easier to work with, ionizing it to give it a charge, then seeing how those ions react to a magnetic field. That reaction tells scientists how much each particle weighs – or, more precisely, what its mass is. The machine then sorts and counts these particles, revealing the specimen’s chemical makeup. The machine is able to distinguish among isotopes. Scientists can learn a lot from knowing how many of which isotopes make up a certain sample.

Spectrometers have served scientists well ever since they were invented a century ago. A number of designs are now in use (the Stardust spaceship even had one on board), with applications that include detecting steroid use in athletes and locating oil deposits. When NASA solicited ideas for better ways to analyze their comet dust, Humayun proposed a novel twist on an existing type of spectrometer called a Laser Ablation Inductively Coupled Plasma Mass Spectrometer (a mighty mouthful that can be shortened into LA-ICP-MS).

To understand the amount of data this first-of-its-kind machine will be able to extract from the comet particles, we need first to understand the basic principles of mass spectrometry – MS for short.

Ladies and gentlemen, start your brain cells!

Next Page Science in the Fast Lane

1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | Links | Full Article