Fragmentation of biomolecules using slow highly charged ions

Abstract

We present first results of biomolecular fragmentation studies with slow highly charged ions (HCI). A thin layer of the tripeptide RVA was deposited on gold targets and irradiated with slow (few 100 keV) ions, e.g. Xe50+ and Xe15+, extracted from the LLNL EBIT (electron beam ion trap). The secondary ions released upon ion impact were mass analyzed via Time-Of-Flight Secondary-Ion-Mass-Spectrometry (TOF-SIMS). The results show a strong dependence of the positive and negative ion yields on the charge state of the incident ion. We also found that incident ions with high charge states cause the ejection of fragments with a wide mass range as well as the intact molecule (345 amu). The underlying mechanisms are not yet understood but electron depletion of the target due to the high incident charge is likely to cause a variety of fragmentation processes.