Encyclopedia of Biophysics

Living Edition
| Editors: Gordon Roberts, Anthony Watts, European Biophysical Societies

Mass Spectrometry: Methods of Ionization (Applied to Biopolymers)

  • Neil J. OldhamEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-35943-9_208-1


Ionization: the process of converting atoms or molecules to ions. In the context of biopolymer mass spectrometry, this usually involves the addition or removal of protons.


The mass spectrometric analysis of biopolymers such as proteins, peptides, oligonucleotides, and carbohydrates has been revolutionized by the development of two key ionization methods: electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI). Both methods facilitate the transfer of large, polar biomolecules from the condensed phase in to the gas phase, permitting determination of their mass/charge ratios (m/z). In the case of ESI, ionization of the biomolecules takes place in solution, under the influence of a strong electric field and before evaporative desolvation of the analyte. MALDI is achieved by embedding the biomolecule in a crystalline matrix capable of absorbing energy from laser irradiation, which causes both desorption and ionization. For large...

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© European Biophysical Societies' Association (EBSA) 2018

Authors and Affiliations

  1. 1.School of ChemistryThe University of NottinghamNottinghamUK

Section editors and affiliations

  • Neil J. Oldham
    • 1
  1. 1.School of ChemistryThe University of NottinghamNottinghamUK