title: H/D exchange of gas phase bradykinin ions in a linear quadrupole ion trap.
abstract: The gas phase H/D exchange reaction of bradykinin ions, as well as fragment ions of bradykinin generated through collisions in an orifice skimmer region, have been studied with a linear quadrupole ion trap (LIT) reflectron time-of-flight (rTOF) mass spectrometer system. The reaction in the trap takes only tens of seconds at a pressure of few mTorr of D2O or CD3OD. The exchange rate and hydrogen exchange level are not sensitive to the trapping q value over a broad range, provided q is not close to the stability boundary (q = 0.908). The relative rates and hydrogen exchange levels of protonated and sodiated +1 and +2 ions are similar to those observed previously by others with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer system. The doubly and triply protonated ions show multimodal isotopic distributions, suggesting the presence of several different conformations. The y fragment ions show greater exchange rates and levels than a or b ions, and when water or ammonia is lost from the fragment ions, no exchange is observed.
authors.affiliation: Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Dunmin
authors.initials: D
authors.lastname: Mao
authors.forename: D J
authors.initials: DJ
authors.lastname: Douglas
mesh_terms: D001920:Bradykinin / Q000737:chemistry*; D003903:Deuterium / Q000737:chemistry*; D017666:Deuterium Oxide / Q000737:chemistry; D004563:Electrochemistry; D005740:Gases / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D007474:Ion Exchange; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry; D011522:Protons
chemical_list: D005740:Gases; D007477:Ions; D011522:Protons; D006859:Hydrogen; D003903:Deuterium; D017666:Deuterium Oxide; D001920:Bradykinin