The nonapeptide bradykinin (BK) was introduced into an ion trap mass spectrometer by electrospray ionization. The doubly and triply protonated ions [BK+2H]2+ and [BK+3H]3+ were individually selected and fragmented while varying the collision energy in MS-MS mode. The lowest energy fragmentation pathway depends on charge state: [BK+2H]2+ yields b2+y7 ions and [BK+3H]3+ yields b6+y3 ions. At higher collision energies, [BK+2H]2+ yields predominantly b1+y8 ions though all possible bn+y9−n are observed; [BK+3H]3+ yields predominantly b6+y3 ions with somewhat less variety. Comparison with a previous study of solution-phase BK fragmentation in H2O, MeOH, EtOH, and 1-PrOH shows that solvent must influence the preferred pathway, even in the “dry” solvent 1-propanol.

Gas-phase fragmentation pathways of bradykinin ions and comparison to solution-phase results

2019 Spring National Meeting

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