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An electrospray ionization tandem mass spectrometric study of p ‐ tert ‐butylcalix[6]arene complexation with ammonium hydroxide, and ammonium and sodium ions
Author(s) -
Sassine André,
MartinsJúnior Helio A.,
Lebre Daniel T.,
Valli Felipe,
Pires Maria A. F.,
Vega Oscar,
Felinto Maria C. F. C.
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.3352
Subject(s) - chemistry , ion , electrospray ionization , molecule , fragmentation (computing) , mass spectrometry , ammonium , mass spectrum , tandem mass spectrometry , electrospray , sodium , ammonia , medicinal chemistry , analytical chemistry (journal) , organic chemistry , chromatography , computer science , operating system
The formation of complexes involving p ‐ tert ‐butylcalix[6]arene with neutral and charged species has been investigated by tandem mass spectrometry combined with electrospray ionization. Complexes of p ‐ tert ‐butylcalix[6]arene with NH 4 +ions were observed in the ratios 1:1, 2:1, and 3:1, together with the complexes of p ‐ tert ‐butylcalix[6]arene with NH 4 OH and Na + ions in the ratios 1:1:1, 2:1:1, and 3:1:1. A single 1:1 complex of p ‐ tert ‐butylcalix[6]arene with Na + ions was observed. In addition, a doubly charged complex of p ‐ tert ‐butylcalix[6]arene with NH 4 OH, Na + , and NH 4 +ions in the ratio 6:1:1:1 was observed. The identity of each complex was determined by mass analysis of product ions formed by the application of a declustering potential over the range 20–220 V and by observation of product ion mass spectra wherein the collision energy was varied from 5 to 50 eV. Fragmentation of the complexes is characterized by the facile loss of the ammonia molecule, sodium and ammonium ions, loss of neutral p ‐ tert ‐butylcalix[6]arene, and successive neutral losses of C 4 H 8 from the six tert ‐butyl groups in each p ‐ tert ‐butylcalix[6]arene molecule. Copyright © 2008 John Wiley & Sons, Ltd.