Introduction to Mass Spectra (by:Cheng Lu)

1. Introduction
Mass Spectrometer (MS) is a kind of machine which uses an analytical technique to measure the mass-tocharge ratio of ions. This analytical technique is also known as Mass spectrometry. And an ion is an atom or
group of atoms which have lost or gained one or more electrons, making them negatively or positively
charged. [1]
Mass spectrometry is an important emerging method for the characterization of proteins. The two primary methods for ionization of whole proteins are electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI).
As it is an important tool in proteomics, it is essential to understand not only the results, but also the principles of Mass Spectrometer. This report is devoting to provide a simple but clear explanation to the principles of Mass Spectrometer

2. General Structure of Mass Spectrometer
Generally, a typical Mass Spectrometer consists of three parts: an ion source, a mass analyzer and a detector.The function of the ion source is to produce ions from the sample. The function of the Mass Analyzer is to separate ions with different mass-to-charge ratios. Then the numbers of different ions are detected by the
detector.