HEAVY CLUSTER IMPACT DESORPTION OF LARGE MOLECULES

拟议研究的长期目标是发展，

The long term objectives of the proposed research are to develop, manufacture and market new instrumentation for the sputtering of large, fragile, molecules. This new technology, called massive cluster impact mass spectrometry(MCIMS), is based on using massive, multiply charged, organic clusters as the primary beam for desorbing sample ions entrained in liquid matrices. We propose to meet these objectives by developing a bipolar (positive or negative) massive cluster ion beam source capable of impacting glycerol matrices with energies/nucleon in the range 0.01 eV/amu less than E/N less than 1.0 eV/amu providing an extremely soft method for sputtering intact molecules. The sputtering process, governed by shock wave phenomenon, is expected to provide enhanced secondary ion yields with significantly reduced ionization and radiation damage of matrix material. With these benefits, massive cluster impact spectra show lower chemical noise background and improved signal-to- noise ratios. In addition to the desorption of large biomolecules, this new "soft" ionization method should prove advantageous for the mass spectral analyses of mixtures, the study of solution phase chemistry and the investigation of fundamental aspects of desorption processes.