✦ LIBER ✦

Ionization mechanisms in matrix-assisted laser desorption/ionization mass spectrometry: contribution of pre-formed ions

✍ Scribed by Edda Lehmann; Richard Knochenmuss; Renato Zenobi

Publisher: John Wiley and Sons
Year: 1997
Tongue: English
Weight: 316 KB
Volume: 11
Category: Article
ISSN: 0951-4198
DOI: 10.1002/(sici)1097-0231(199709)11:14<1483::aid-rcm982>3.0.co;2-f

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✦ Synopsis

The mechanisms of ion formation in matrix-assisted laser desorption/ionization mass spectrometry are still largely unknown. Ions may exist as pre-formed species in the solid state, or may form by ion-molecule reactions initiated by the laser shot, or, most probably, they may originate from a combination of both processes. The contribution of pre-formed ions was approached from the standpoint of coordination chemistry and studied in different transition metal ion/matrix systems as well as in the copper/polystyrene system. The solution, the solid and the gas phases were investigated by means of infrared, visible and proton nuclear magnetic resonance spectroscopy, as well as by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. It was found that the contribution of pre-formed ions can be predicted on the basis of condensed phase thermodynamics. MALDI mass spectra qualitatively reflect the amount of pre-formed complexes in the solid target.

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