Ion trap mass analysis at high pressure: an experimental characterization.
In recent years, it has become increasingly interesting to understand the performance of mass spectrometers at pressures much higher than those employed with conventional operating conditions. This interest has been driven by several influences, including demand for the development of reduced-power miniature mass spectrometers, desire for improved ion transfer into and through mass spectrometers, enhanced-yield preparative mass separations, and mass filtering at the atmospheric pressure interface. In this study, an instrument was configured to allow for the performance characterization of a rectilinear ion trap (RIT) at pressures up to 50 mtorr with air used as the buffer gas. The mass analysis efficiency, mass resolution, isolation efficiency, and collision-induced dissociation (CID) efficiency were evaluated at pressures ranging from 1 to 50 mtorr. The extent of degradation of mass resolution, isolation efficiency and ion stability as functions of pressure were characterized. Also, the optimal resonance ejection conditions were obtained at various pressures. Operations at 50 mtorr demonstrated improved CID efficiency in addition to peak widths of 2 and 5 m/z units (full width at half-maximum, FWHM) for protonated caffeine (m/z 195) and Ultramark (m/z 1521) respectively.
Song
Qingyu
Q
Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
Xu
Wei
W
Smith
Scott A
SA
Gao
Liang
L
Chappell
William J
WJ
Cooks
R Graham
RG
Ouyang
Zheng
Z
D004867:Equipment Design; D007477:Ions / Q000032:analysis; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods; D011312:Pressure; D011506:Proteins / Q000032:analysis
D007477:Ions; D011506:Proteins