page_title: Electrospray ionization
section_title: Applications
hierarchical_section_title: Electrospray ionization / Applications
caption_attribution_description: LTQ-ESI. The electrospray interface on the LTQ (Linear Trap Quadrupole).
context_page_description: Electrospray ionization is a technique used in mass spectrometry to produce ions using an electrospray in which a high voltage is applied to a liquid to create an aerosol. It is especially useful in producing ions from macromolecules because it overcomes the propensity of these molecules to fragment when ionized. ESI is different from other ionization processes since it may produce multiple-charged ions, effectively extending the mass range of the analyser to accommodate the kDa-MDa orders of magnitude observed in proteins and their associated polypeptide fragments.
  Mass spectrometry using ESI is called electrospray ionization mass spectrometry or, less commonly, electrospray mass spectrometry. ESI is a so-called 'soft ionization' technique, since there is very little fragmentation. This can be advantageous in the sense that the molecular ion is always observed, however very little structural information can be gained from the simple mass spectrum obtained. This disadvantage can be overcome by coupling ESI with tandem mass spectrometry. Another important advantage of ESI is that solution-phase information can be retained into the gas-phase.
context_section_description: Electrospray is used to study protein folding.
caption: The outside of the electrospray interface on an LTQ mass spectrometer.
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