Simplification of product ion spectra derived from multiply charged parent ions via ion/ion chemistry.
High-mass multiply charged ions fragment to yield a mixture of products of varying mass and charge. When the measurement of mass-to-charge ratio is used to determine products ion mass, product ion charge must first be established. To minimize charge-state ambiguity in product ion spectra derived from multiply charged parent ions, product ions have been subjected to proton-transfer reactions with oppositely charged ions to reduce product ion charge states largely to +1. This procedure greatly simplifies the interpretation of product ion spectra derived from multiply charged ions. Illustrative data are presented for the +4 and +3 parent ions derived from electrospray of melittin and the +12 to +4 parent ions of bovine ubiquitin, whereby product ions were formed in a conventional quadrupole ion trap tandem mass spectrometry experiment. Data are also shown for product ion mixtures derived from interface-induced dissociation of multiply charged ions derived from bovine ubiquitin, tuna cytochrome c, bovine cytochrome c, and equine cytochrome c. The use of ion/ion chemistry to simplify product ion spectra derived from multiply charged parent ions significantly extends the size range of macromolecules for which the quadrupole ion trap can derive structural information.
Stephenson
J L
JL
Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Tennessee 37831-6365, USA.
McLuckey
S A
SA
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003574:Cytochrome c Group / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D008555:Melitten / Q000737:chemistry; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry*; D014413:Tuna; D014452:Ubiquitins / Q000737:chemistry
D003574:Cytochrome c Group; D011506:Proteins; D014452:Ubiquitins; D008555:Melitten