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Extending the mass range of the quadrupole ion trap using axial modulation
Author(s) -
Kaiser Raymond E.,
Louris John N.,
Amy Jonathan W.,
Cooks R. Graham,
Hunt D. F.
Publication year - 1989
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.1290030706
Subject(s) - chemistry , ion trap , ion , quadrupole ion trap , mass spectrometry , atomic physics , quadrupole , trap (plumbing) , analytical chemistry (journal) , mass spectrum , ion source , protonation , detection limit , chromatography , physics , organic chemistry , meteorology
Secondary‐ion mass spectrometry, using Cs + ion bombardment of solid and liquid matrices, has been implemented on a quadrupole ion trap. Tetraalkylammonium cations and protonated peptides, generated in an external source using a pulsed primary‐ion beam, are injected into the ion trap where they are decelerated and trapped in the course of collisions with the helium bath gas. The contents of the trap are then examined by recording a mass spectrum using the mass‐selective instability scan. To improve performance in the examination of these trapped ions, the technique of axial modulation is used to cause resonance ejection of ions from the trap during the mass‐analysis step. The supplementary AC voltage applied to the end‐caps causes resonant ejection of ions at q z values below those which correspond to the normal stability limit. This is demonstrated to increase the mass limit of a commercial ion trap from 650 Da to approximately 1300 Da with no loss in resolution or sensitivity, and to more than 20 000 Da at reduced sensitivity.