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Generation and collision‐induced dissociation of ammonium tetrafluoroborate cluster ions
Author(s) -
Dain Ryan P.,
Van Stipdonk Michael J.
Publication year - 2008
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.3586
Subject(s) - chemistry , dissociation (chemistry) , collision induced dissociation , ion , electrospray ionization , fragmentation (computing) , tandem mass spectrometry , analytical chemistry (journal) , tetrafluoroborate , mass spectrometry , ammonium , cluster (spacecraft) , chromatography , biochemistry , ionic liquid , organic chemistry , computer science , catalysis , programming language , operating system
Singly and doubly charged cluster ions of ammonium tetrafluoroborate (NH 4 BF 4 ) with general formula [(NH 4 BF 4 ) n NH 4 ] + and [(NH 4 BF 4 ) m (NH 4 ) 2 ] 2+ , respectively, were generated by electrospray ionization (ESI) and their fragmentation examined using collision‐induced dissociation (CID) and ion‐trap tandem mass spectrometry. CID of [(NH 4 BF 4 ) n NH 4 ] + caused the loss of one or more neutral NH 4 BF 4 units. The n = 2 cluster, [(NH 4 BF 4 ) 2 NH 4 ] + , was unique in that it also exhibited a dissociation pathway in which HBF 4 was eliminated to create [(NH 4 BF 4 )(NH 3 )NH 4 ] + . Dissociation of [(NH 4 BF 4 ) m (NH 4 ) 2 ] 2+ occurred through two general pathways: (a) ‘fission’ to produce singly charged cluster ions and (b) elimination of one or more neutral NH 4 BF 4 units to leave doubly charged product ions. CID profiles, and measurements of changing precursor and product ion signal intensity as a function of applied collision voltage, were collected for [(NH 4 BF 4 ) n NH 4 ] + and compared with those for analogous [(NaBF 4 ) n Na] + and [(KBF 4 ) n K] + ions to determine the influence of the cation on the relative stability of cluster ions. In general, the [(NH 4 BF 4 ) n NH 4 ] + clusters were found to be easier to dissociate than both the sodium and potassium clusters of comparable size, with [(KBF 4 ) n K] + ions the most difficult to dissociate. Copyright © 2008 John Wiley & Sons, Ltd.