Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5368878 | Applied Surface Science | 2006 | 4 Pages |
Chemical tags such as anthracene can be attached to a molecular analyte and serve as chromophores for 7.87Â eV laser postionization by lowering the overall ionization potential of the tagged molecular complex. Fluorescein and tryptophan are demonstrated as two new tags for 7.87Â eV laser postionization of various amino acids and peptides. Other molecular species that are efficient fluorescence probes should also serve as tags for 7.87Â eV postionization since they display highest occupied molecular orbitals with extended Ï-conjugation that lead to ionization potentials below this photon energy and an ability to stabilize the net positive charge of the radical cations. This technique is demonstrated here for laser desorbed species, but is also applicable to keV ion sputtered neutrals. Overall, 7.87Â eV laser postionization of derivatized species promises to expand the capabilities of mass spectrometric surface analysis.