Surface-Induced Dissocintion versiis Collision-Induced Dissociation: The Bruker 7 Tesla Fourier transform ion-cyclotron resonance (FTICR) mass spectrometer was modified to insert a surface inside the cell for ion-surface collisions leading to the dissociation of impacting ions. The surface was monnted in the ICR cell through an aperture in the back trapping plate. Necessary modifications were made to the software/ hardware to collide the ions brought into the celI and trap the resulting

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... and undissociated Firnary ions h i d e the cell. The trapping plates were also ramped to determine kinetic energy distributions of these ions. We used self assembled monolayer (SAM) surface of FClz alkanethiol (CFJ!CF&(CH~)~SH) on gold surface formed by immersing it in a 1 mM ethanol solution of the surface material. We first studied surfaceinduced dissociation (SID) of benzene and chromium hexacarbonyl ions as test cases for the instrument since the energetics and dissociation dynamics of these ions is very well understood from photoelectron photoion coincidence (PEPICO), photoionization (PI) and several other studies. Furthermore, their SID processes have been previously investigated by us on OUT 3 Tesla FT ICR and by others using different instrumentations. After these studies established the suitability and ease ofperforming SID experiments on this instrument, we began a systematic study of the SID of small protonated peptides formed by electrospray ionization. A series of small alanine (A) containing peptides, viz., AA, AAA, AAAA, A A U A and PAAAA were used in the present study. >