On the mechanism and control of salt-induced resolution loss in matrix-assisted laser desorption/ionization

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Eur. J. Mass Spectrom. 2, 167 - 172 (1996)

On the mechanism and control of salt-induced resolution loss in matrix-assisted laser desorption/ionization

Frédéric Dubois, Richard Knochenmuss, Ruud J.J.M. Steenvoorden, Kathrin Breuker and Renato Zenobi^*
Department of Chemistry, ETHZ Zentrum, CH-8092 Zürich, Switzerland.

ABSTRACT:

The effects of salt impurities in matrix-assisted laser desorption/ionization were studied. It was observed that, when metal cations are present in the sample, they can induce clustering between matrix and analyte molecules. Such cluster-adducts can lead to loss of mass resolution, especially for high molecular weight analytes, such as proteins, and for samples where salts are naturally present. The evidence indicates that these cluster-adducts are formed in the matrix, before desorption. Acidic preparation conditions and a high polarity solvent can significantly reduce clustering and therefore improve mass resolution and accuracy.

Keywords:

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