Mass Spectrometry

Written by Tony Harris, August 18, 2016

 

Spectrum: The word is derived from the Latin word to look and was used describe an image or ghost. The word spectrum was first used, by Isaac Newton, in the field of optics to refer to the output of a prism. Such as the one depicted on Pink Floyd’s “Dark Side of The Moon” album. Good album that, alas I digress. Soon the term expanded to apply to other waves that could be measured as a function of frequency. For example sound waves and all types of electromagnetic waves. It later became used to describe any continuum.

So when we talk about spectral analysis we are referring to a measurement of some function along a continuous variable. A spectral analysis of a rainbow for example would consider the intensity of light as a function of the colors present. If we did a spectral analysis of someone’s speech we would find that certain frequencies were more common than others.

Mass Spectrometry is name given to a technique that allows us to identify materials by analyzing their mass to charge ratio. Mass spectrometry was invented at the University of Birmingham by Francis Aston. He received the Nobel Prize in Chemistry for his invention in 1922. My father worked on the mass spectrometer at the University of Birmingham in the mid-1940’s but he didn’t get a Nobel Prize.

In its simplest form a mass spectrometer uses an electric field to accelerate ions and then uses a magnetic field to deflect them. Depending upon the ratio of the electric charge to the mass, the ions will be separated and so can be identified by their mass/charge ratio. One type of mass analyzer used in mass spectrometry is a quadrupole. Here an rf (radio frequency) signal is applied to four conductors. As the ions travel through the quadrupole the electric field set up by the rf signal will cause ions with a specific mass/ charge ratio to reach the detector.

Matt Brantley of Baylor University presented a poster at the ARMS conference in San Antonio, Texas earlier this year entitled: A Modular Data Station for Radio-Frequency Ionization FT-ICR Mass Spectrometry Imaging. We were pleased to work with Matt on the Amplifier and balun circuitry for his quadrupole. These studies facilitate metabolomics, the understanding of metabolism and the drugs that can help support it. We are excited to be part of this research.

 

Tony Harris August 2016

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