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Axial spatial distribution focusing: improving MALDI‐TOF/RTOF mass spectrometric performance for high‐energy collision‐induced dissociation of biomolecules
Author(s) -
Belgacem O.,
Pittenauer E.,
Openshaw M. E.,
Hart P. J.,
Bowdler A.,
Allmaier G.
Publication year - 2015
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.7458
Subject(s) - reflectron , chemistry , mass spectrometry , mass spectrum , collision induced dissociation , analytical chemistry (journal) , ion source , fragmentation (computing) , ion , spectral line , dissociation (chemistry) , biomolecule , matrix assisted laser desorption/ionization , time of flight mass spectrometry , ionization , atomic physics , desorption , tandem mass spectrometry , chromatography , physics , organic chemistry , astronomy , adsorption , computer science , operating system , biochemistry
Rationale For the last two decades, curved field reflectron technology has been used in matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometers, assisting in the generation of post‐source‐decay (PSD) or collision‐induced dissociation (CID) without decelerating precursor ions, producing true high‐energy CID spectra. The result was the generation of product ion mass spectra with product ions typical of high‐energy (10 keV and beyond) collision processes. The disadvantage of this approach was the lack of resolution in CID spectra resulting from the excess laser energy deposition used to generate those MS/MS spectra. The work presented in this study overcomes this limitation and includes comprehensive examples of high‐energy and high‐resolution CID MALDI‐MS/MS spectra of biomolecules. Methods The devices used in this study are TOF/RTOF instruments equipped with a high‐vacuum MALDI ion source. High‐resolution and high‐energy CID spectra result from the use of axial spatial distribution focusing (ASDF) in combination with curved field reflectron technology. Results A CID spectrum of the P 14 R 1 peptide exhibits product ion resolution in excess of 10,000 (FWHM) but at the same time yields typical high‐energy product ions such as w‐ and [y–2]‐type ion series. High‐energy CID spectra of lipids, exemplified by a glycerophospholipid and triglyceride, demonstrate C–C backbone fragmentation elucidating the presence of a hydroxyl group in addition to double‐bond positioning. A complex high mannose carbohydrate (Man) 8 (GlcNAc) 2 was also studied at 20 keV collision energy and revealed further high‐energy product ions with very high resolution, allowing unambiguous detection and characterization of cross‐ring cleavage‐related ions. Conclusions This is the first comprehensive study using a MALDI‐TOF/RTOF instrument equipped with a curved field reflectron and an ASDF device prior to the reflectron. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd.