Internal energy effects on charge stripping spectra of [C7H8]+ and [C5H6]+ radical cations

MS/MS/MS experiments were carried out using a large-scale tandem mass spectrometer featuring a sector-quadrupole-sector geometry to probe the C7H8+ and C5H6+ radical cations. These ions (m/z 92 and 66) were produced from metastable ionized precursors or charge exchange reactions in the quadrupole cell; subsequent fragmentations and double ionization were performed after mass-selection and collisional activation with oxygen. Charge stripping spectra show significant variations in the relative intensities of the same doubly charged species generated in different ways. These variations are likely to be associated with the inherent differences in internal energy content.