Mass Analyzers and Mass Spectrometers

Mass spectrometers are comprised of three main components: an ion source, a mass analyzer, and a detector. Ionization of the analyte occurs in the ion source and the resulting ions are counted at the detector. However, it is the mass analyzer that is responsible for determing the mass-to-charge ratio (m/z) of the ions (Jennings KR, Dolnikowski GG, Method Enzymol 193:37-61, 1990). Therefore, it is primarily the analyzer that allows the mass spectrometer to serve its primary goal-determining the mass of the analytes being measured. This becomes important in the field of molecular biology, where biomolecules may be of low molecular weight or often take on multiple charges (z) after ionization (Fenn JB, Mann M, Meng CK, Wong SF, Whitehouse CM, Science 246:64-71, 1989). For this reason, the choice of analyzer is dependant on the properties of the analyte after ionization and the requirements of the experiment being performed.