General Principles of Mass Spectrometry
Mass spectrometry (MS), one of the most sensitive and powerful analytical methods, is based on the determination of the molecular masses, being frequently called “the smallest scale in the world''. Hence, the fundamental difference between mass spectrometry and the rest of spectral techniques is that MS does not involve electromagnetic radiation (de Hoffmann et al., 2007).
Although in the last years a tremendous number of MS configurations were conceived, produced and released on the market by specialized companies, the basic elements of all mass spectrometers are the same (Figure 1):
Figure 1. Mass spectrometer – block diagram
- 1.
The ion source that produces the ionization of the analyte;
- 2.
The mass analyzer, which separates the ions according to their mass-to-charge ratio (m/z) and
- 3.
The ion detector, a device for measuring the current of the ionic beam.
Each MS instrument has also a vacuum system to control the pressure and to minimize the ion reactions. In MS, neutral sample molecules are ionized and further accelerated into the mass analyzer. In this section, the ions are separated according with their mass to charge ratio. After this process, the ions are detected and the signal is transferred to a data system for analysis (de Hoffmann et al., 2007).
Obviously, each of the MS components can be found in many configurations; these elements are basically combined to produce a wide variety of mass spectrometers with highly specialized characteristics.
Nowadays, mass spectrometry is one of the most efficient methods in the analysis of biomolecules such as proteins, carbohydrates and nucleic acids being considered the key technology in the emerging fields of proteomics, glycomics and genomics. The success of modern mass spectrometry is driven by the highly innovative instrumentation designs and by the large scale of strategies, which use this technique to detect, de novo identify and structurally characterize in details molecular species originating from various biological matrices.