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Desorption/ionization induced by neutral cluster impact as a soft and efficient ionization source for ion trap mass spectrometry of biomolecules
Author(s) -
Baur Markus,
Gebhardt Christoph R.,
Dürr Michael
Publication year - 2013
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6781
Subject(s) - chemistry , mass spectrometry , ionization , biomolecule , cluster (spacecraft) , ion source , ion , ambient ionization , ion trap , direct electron ionization liquid chromatography–mass spectrometry interface , desorption , analytical chemistry (journal) , chemical ionization , chromatography , adsorption , organic chemistry , computer science , biochemistry , programming language
RATIONALE Desorption and ionization induced by neutral clusters (DINeC) using SO 2 as cluster constituents was previously shown to produce clear and fragmentation‐free spectra with low background from samples prepared with standard oligopeptides. Here we demonstrate a more general applicability of this method based on examples from different classes of (bio‐)molecules. In order to make better use of the ions generated during the millisecond cluster‐pulse, the DINeC source was combined with an ion trap mass spectrometer. METHODS Desorption and ionization was induced by neutral SO 2 clusters with a mean size of 10 3 to 10 4 molecules seeded in a pulsed He beam. The desorbed ions were accumulated in an ion trap over the whole pulse duration prior to mass spectrometric analysis. Samples were prepared by simply drop casting the respective aqueous solution of biomolecules on Si/SiO 2 substrates. RESULTS Clear and fragmentation‐free spectra of oligopeptides were detected in single pulse operation mode. The very soft nature of the desorption process was demonstrated for phosphopeptides. DINeC spectra from bovine serum albumin samples after tryptic digest led to a clear identification of the original sequence using mass fingerprinting analysis. MS n capability was illustrated with two types of rhodamine dyes. CONCLUSIONS Desorption and ionization induced by neutral clusters can efficiently be combined with ion trap mass spectrometry since the pulse width and repetition rate of a typical pulsed cluster beam correspond well to the discontinuous accumulation time as well as the spectral rate of the ion trap. Clear mass spectra were obtained with such a setup for a variety of biosamples demonstrating the wider applicability of the DINeC process. Copyright © 2013 John Wiley & Sons, Ltd.