2. Academic Validation
  3. The history of electron ionization in LC-MS, from the early days to modern technologies: A review

The history of electron ionization in LC-MS, from the early days to modern technologies: A review

  • Anal Chim Acta. 2021 Jul 4;1167:338350. doi: 10.1016/j.aca.2021.338350.
Giorgio Famiglini 1,  Pierangela Palma 2,  Veronica Termopoli 2,  Achille Cappiello 3
Affiliations

Affiliations

  • 1 LC-MS Laboratory, Department of Pure and Applied Sciences, University of Urbino, Urbino, Italy. Electronic address: giorgio.famiglini@uniurb.it.
  • 2 LC-MS Laboratory, Department of Pure and Applied Sciences, University of Urbino, Urbino, Italy.
  • 3 LC-MS Laboratory, Department of Pure and Applied Sciences, University of Urbino, Urbino, Italy. Electronic address: achille.cappiello@uniurb.it.
PMID: 34049632 DOI: 10.1016/j.aca.2021.338350
Abstract

This review article traces the history of the use of liquid chromatography coupled with mass spectrometry (LC-MS) using electron ionization (EI) from the first attempts up to the present day. At the time of the first efforts to couple LC to MS, 70 eV EI was the most common ionization technique, typically used in gas chromatography-mass spectrometry (GC-MS) and providing highly reproducible mass spectra that could be collated in libraries. Therefore, it was obvious to transport this dominant approach to the early LC-MS coupling attempts. The use of LC coupled to EI-MS is challenging mainly due to restrictions related to high-vacuum and high-temperature conditions required for the operation of EI and the need to remove the eluent carrying the analyte before entering the ion source. The authors will take readers through a journey of about 50 years, showing how through the succession of different attempts it has been possible to successfully couple LC with EI-MS, which in principle appear to be incompatible.

Keywords

Cold-EI; EI; Electron ionization; LC-MS; LEI; Liquid chromatography-mass spectrometry.

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