What's ICR?
The Mag Lab is a world leader in Ion Cyclotron Resonance (ICR), a very powerful method of mass spectrometry (MS). Scientists use MS to figure out the chemical composition of a substance by determining the mass of its component molecules. Below you'll find links to resources (some in the Education section of our Web site) that explain, through words, pictures and interactive tutorials, the techniques, instruments and people associated with ICR.
Articles
Alan Marshall: A Scientist and a Gentleman
Profile of ICR Program Director Alan Marshall, co-inventor of Fourier Transform Ion Cyclotron Resonance.
Fourier Transform Ion Cyclotron Resonance: A Primer
Mass Spectrometry Reviews, Volume 17, Issue 1 (1998)
This popular overview article by Mag Lab scientists (including ICR Program director and FT-ICR co-inventor Alan Marshall) is available from the publisher's Web site.
What's in an Oil Drop: An Introduction to Fourier Transform Ion Cyclotron Resonance (FT-ICR)
Written with non-scientists in mind, this article describes in very accessible terms how FT-ICR works, using as an example the analysis of a drop of crude oil.
Ionization Techniques
In order to undergo FT-ICR, a sample must first be ionized. That means turning the liquid sample into a gas while applying a charge to it, making each of the atoms or molecules under study a positively or negatively charged particle (ion). The charge is critical to allowing the cyclotron's magnet to determine its mass. There are many methods of ionization, each offering its own advantages; below are some used at the Magnet Lab.
Atmospheric Pressure Photoionization (APPI)
In the APPI technique, UV light photons are used to ionize sample molecules.
Electrospray Ionization (ESI)
Electrospray ionization is a popular technique in mass spectroscopy for ionizing samples before they are measured. ESI works well with heavier compounds and is therefore often used in proteomics (analysis of proteins) and petroleomics (analysis of petroleum).
Matrix-Assisted Laser Desorption Ionization (MALDI)
MALDI, a method of ionization that has been widely used since its introduction in the late 1980s, has been of great help to scientists studying polymers, proteins and other heavy molecules. This is how it works.
Interactive Java Tutorials
Fourier Transform Ion Cyclotron Resonance
This applet depicts the basics of this technique, helping you visualize a process that cannot otherwise be observed.
Magnet Lab Web Resources
- Weighing Atoms: A Race Odyssey
This article covers how mass spectrometry is used to examine comet dust.
- Right and Left Hand Rules
Interactive Java Tutorial: You’ll find two of the most useful tools for understanding electromagnetism right at the end of your arms.
- Single Sector Mass Spectrometer
Interactive Java Tutorial: The single sector mass spectrometer is made with a single magnetic analyzer.
- Dual Sector Mass Spectrometer
Interactive Java Tutorial: The dual sector mass spectrometer has two analyzers – one magnetic, one electrostatic.
- Mass Spectra
Interactive Java Tutorial: The mass spectrum of a material, deduced using a machine called a mass spectrometer, reveals how many isotopes of a given element are to be found in the material. See here what these spectra look like and how they are useful.
- Reading Chemical "Fine Print": The Key to Unlocking Nature's Isotopic Zoo
This link directs you to an online video of a presentation given by ICR Program Director Alan Marshall in November 2006.
Other Web Resources
About FT-ICR
About Mass Spectrometry in General
