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Pulsed helium introduction into a quadrupole ion trap for reduced collisional quenching during infrared multiphoton dissociation of electrosprayed ions
Author(s) -
Boué Stephen M.,
Stephenson James L.,
Yost Richard A.
Publication year - 2000
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 - 10.1002/1097-0231(20000815)14:15<1391::aid-rcm36>3.0.co;2-o
Subject(s) - infrared multiphoton dissociation , chemistry , quadrupole ion trap , buffer gas , ion , ion trap , helium , atomic physics , mass spectrometry , dissociation (chemistry) , photodissociation , ion trapping , reflectron , analytical chemistry (journal) , ion source , tandem mass spectrometry , laser , ionization , photochemistry , optics , time of flight mass spectrometry , physics , organic chemistry , chromatography
Previous infrared multiphoton dissociation (IRMPD) experiments utilizing a quadrupole ion trap mass spectrometer yielded limited photodissociation efficiencies. Helium buffer gas continuously infused into the analyzer region at pressures of typically 1 × 10 −3 Torr to improve ion trap performance can collisionally quench photoexcited ions during the IRMPD process. Photodissociation experiments have indicated that uncorrected pressures below 2 × 10 −5 Torr are necessary to avoid collisional deactivation of photoexcited ions. This paper describes IRMPD in the quadrupole ion trap at reduced pressures utilizing a dual‐pulsed introduction of helium buffer gas incorporated into the ion trap scan function. The pulsed introduction of helium buffer gas before ion injection allows the efficient trapping of ions injected from an electrospray source and the removal of helium before laser irradiation. A second pulse of helium directly before ion detection improves the intensity of the ion signal. The use of this dual‐pulsed inlet of helium for improved IRMPD is demonstrated with the carbohydrate antibiotics neomycin and erythromycin. Copyright © 2000 John Wiley & Sons, Ltd.