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A novel differentially pumped design for atmospheric pressure ionization‐ion trap mass spectrometry
Author(s) -
Mordehai Alex V.,
Henion Jack D.
Publication year - 1993
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.1290070308
Subject(s) - chemistry , ion trap , torr , ion , mass spectrometry , electron multiplier , helium , quadrupole ion trap , analytical chemistry (journal) , atmospheric pressure , atomic physics , ionization , helium ionization detector , trap (plumbing) , penning trap , vacuum chamber , electron ionization , materials science , chromatography , physics , organic chemistry , meteorology , thermodynamics , composite material
A novel differentially pumped design for atmospheric pressure ionization (API)‐ion trap mass spectrometry is described. The vacuum system consists of three stages of pumping: API interface stage (1060 L/min), ion trap vacuum region (520 L/s) and electron multiplier region (60 L/s). The ion trap vacuum chamber has been specially designed to implement differential pumping of the ion trap and electron multiplier regions thus allowing ion trap operation with unit mass resolution at pressures up to 6 × 10 −3 Torr of helium while maintaining high vacuum in the electron‐multiplier detector region. Trapping efficiency for accumulating externally produced ions was studied at unusually high pressures of the damping gas (helium) up to a pressure of 7 × 10 −3 Torr (medium vacuum region). The trapping efficiency for externally produced ions and hence the overall mass spectrometric sensitivity is significantly improved by the introduction of helium damping gas into the ion trap region up to 6 × 10 −3 Torr.