MS/MS/MS experiments were carried out using a large-scale tandem mass spectrometer featuring a sector-quadrupole-sector geometry to probe the C7H8center dot+ and C5H6center dot+ radical cations. These ions (m/z 92 and 66) were produced from metastable ionized precursors or charg 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. (c) 2005 Elsevier B.V. All rights reserved.