Proton-transfer reactions of mass-selected multiply charged ions.
A triple-quadrupole spectrometer has been used to study proton-transfer reactions of multiply charged ions generated by electrospray ionization. Doubly and triply charged ions generated from the peptides Arg-Lys-Glu-Val-Tyr and Met-Lys-bradykinin, respectively, were found to undergo proton-transfer reactions with ammonia molecules contained in the RF-only quadrupole collision-gas cell of the spectrometer. With horse-heart myoglobin in the source, ions having charges of 20+, 19+, 16+ and 14+ were selected in turn by the first quadrupole and their proton-transfer reactions with ammonia investigated. For each ion, numerous product ions were detected having charges (n-1)+, (n-2)+, (n-3)+ ... where n was the charge on the reacting parent ion. The possibility of using the experimental technique to measure approximately the proton affinities of multiply charged ions is discussed. Also, a procedure is outlined for identifying the charge states of product ions resulting from collision-induced dissociation of multiply charged ions.
Hunter
A P
AP
Mass Spectrometry Research Unit, University College of Swansea, UK.
Severs
J C
JC
Harris
F M
FM
Games
D E
DE
D000595:Amino Acid Sequence; D000641:Ammonia / Q000737:chemistry; D000818:Animals; D001920:Bradykinin / Q000737:chemistry; D006736:Horses; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry; D009211:Myoglobin / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D011522:Protons
D009211:Myoglobin; D010455:Peptides; D011522:Protons; D000641:Ammonia; D001920:Bradykinin