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[摘要]：Electron detachment dissociation (EDD) and electron photodetachment dissociation (EPD) are relatively new dissociation methods that involve electron detachment followed by radical-driven dissociation from multiply deprotonated species. EDD yields prompt dissociation whereas only electron detachment is obtained by EPD; subsequent vibrational activation of the charge-reduced radical anion is required to obtain the product ions. Herein, the fragmentation patterns that were obtained by EDD and by vibrational activation of the charge-reduced radical anions that were produced through EDD or EPD (activated-EDD and activated-EPD) were compared. The observed differences were related to the dissociation kinetics and/or the contribution of electron-induced dissociation (EID). Time-resolved double-resonance experiments were performed to measure the dissociation rate constants of the EDD product ions. Differences in the formation kinetics were revealed between the classical EDD/EPD 'a(i)(center dot)/'' x(j) complementary ions and some 'a(i)(center dot)/c(i)/'''z(j)(center dot) product ions, which were produced with slower dissociation rate constants, owing to the presence of specific neighbouring side chains. A new fragmentation pathway is proposed for the formation of the slow-kinetics 'a(i)(center dot) ions. |
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