High desorption-ionization yields of large biomolecules induced by fast C-60 projectiles

C-60 molecules accelerated to MeV energies (20 MeV) have been used to induce the desorption-ionization of large bio-molecules from solid samples. For a sample consisting of trypsin molecules, the secondary molecular ion emission yield is about two orders of magnitude larger than with MeV atomic ions. This is a consequence of the very high energy density deposited in solids by 20 MeV C-60 projectiles that gives rise to a large amount of matter ejected after each impact. Although time-of-flight mass spectra can be recorded within a few seconds, it is more the acquisition of knowledge on mechanistic aspects, in comparison with other particle-induced desorption methods, which is the objective of obtaining these first results with energetic fullerenes. (C) 1997 Elsevier Science B.V.