Dual buffer gases for ion manipulation in a miniature ion trap mass spectrometer with a discontinuous atmospheric pressure interface.

Tsung-Chi Chen, Wei Xu, Zheng Ouyang

Index: Rapid Commun. Mass Spectrom. 25(21) , 3274-80, (2011)

Full Text: HTML

Abstract

The discontinuous atmospheric pressure interface (DAPI) has been developed to allow a direct transfer of ions from atmosphere into an ion trap mass spectrometer with minimum pumping capability. Air is introduced into the trap with ions and used as a buffer gas for the ion trap operation. In this study, a method of introducing helium as a second buffer gas was developed for a miniature mass spectrometer using a dual DAPI configuration. The buffer gas effects on the performance of a linear ion trap (LIT) with hyperbolic electrodes were characterized for ion isolation, fragmentation and a mass-selective instability scan. Significant improvement was obtained with helium for resolutions of mass analysis and ion isolation, while moderate advantage was gained with air for collision-induced dissociation. The buffer gas can be switched between air and helium for different steps within a single scan, which allows further optimization of the instrument performance for tandem mass spectrometry.Copyright © 2011 John Wiley & Sons, Ltd.