Biology Reference
In-Depth Information
Chapter 6
The Expanding Universe of Mass Analyzer Configurations
for Biological Analysis
Juan J. Calvete
Abstract
Mass spectrometry (MS) is an analytical technique that measures the mass-to-charge ratio of electrically
charged gas-phase particles. All mass spectrometers combine ion formation, mass analysis, and ion detec-
tion. Although mass analyzers can be regarded as sophisticated devices that manipulate ions in space and
time, the rich diversity of possible ways to combine ion separation, focusing, and detection in dynamic
mass spectrometers accounts for the large number of instrument designs. A historical perspective of the
progress in mass spectrometry that since 1965 until today have contributed to position this technique as
an indispensable tool for biological research has been recently addressed by a privileged witness of this
golden age of MS (Gelpí J. Mass Spectrom 43:419-435, 2008; Gelpí J. Mass Spectrom 44:1137-1161,
2008). The aim of this chapter is to highlight the view that the operational principles of mass spectrometry
can be understood by a simple mathematical language, and that an understanding of the basic concepts of
mass spectrometry is necessary to take the most out of this versatile technique.
Key words
Mass spectrometry, Mass spectrometers, Mass analyzers, Hybrid mass spectrometers
1
Introduction
The principle of using electric and magnetic fields to accelerate and
establish the trajectories of ions inside the spectrometer according
to their mass-to-charge ratio is common to all the different designs
[
1
,
2
]. Ion motions in a mass analyzers are governed by the field
conditions, and thus understanding how the ion's mass-to-charge
ratio can be derive from a mass spectrometric experiment requires
a knowledge of the parameters involved, which—as described
below—can be summarized in simple equations and diagrams. In
addition, since there is no single mass analyzer capable of perform-
ing all applications required in proteomic researches, knowledge of
the analytical capabilities and performances of the different mass
analyzer configurations available in the market, proteomic services,
or in the laboratories of colleagues is key to take full advantage of
this powerful tool for biological research.
