Effect of protonation and deprotonation on the gas phase reactivity of fluorinated 1,2,4-triazines

Positive and negative electrospray mass spectrometry (MS), in-time and in-space MSn experiments, high-resolution and accurate mass measurements obtained with an Orbitrap, together with density functional theory calculations have been used to study the gas-phase ion chemistry of a series of fluorinated 1,2,4-triazines. As a result of low-energy collision-induced dissociations, occurring in an ion trap and in a triple quadrupole, their protonated and deprotonated molecules show interesting features depending on the nature and structure of the precursor ions. The occurrence of elimination/hydration reactions produced by positive ions in the ion trap is noteworthy. Decompositions of deprotonated molecules, initiated by elimination of a hydroxyl radical from [M-H]-, are dominated by radical anions. Theoretical calculations have allowed us to obtain information on atom sites involved in the protonation and deprotonation reactions. © 2008 American Society for Mass Spectrometry.