title: Mass spectrometry of intact neutral macromolecules using intense non-resonant femtosecond laser vaporization with electrospray post-ionization.
abstract: Intact, nonvolatile, biological macromolecules can be transferred directly from the solid state into the gas phase, in ambient air, for subsequent mass spectral analysis using non-resonant femtosecond (fs) laser desorption combined with electrospray ionization (ESI). Mass spectral measurements for neat samples, including a dipeptide, protoporphyrin IX and vitamin B12 adsorbed on a glass insulating surface, were obtained using an 800 nm, 70 fs laser with an intensity of 10(13) W cm(-2). No appreciable signal was detected when atmospheric matrix-assisted or neat (matrix-free) fs laser desorption was performed without ESI, indicating neutral desorption.
authors.affiliation: Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Brady
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Judge
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Levis
mesh_terms: D004151:Dipeptides / Q000737:chemistry*; D007834:Lasers; D046911:Macromolecular Substances / Q000737:chemistry*; D011524:Protoporphyrins / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods*; D014805:Vitamin B 12 / Q000737:chemistry*; D014835:Volatilization
chemical_list: D004151:Dipeptides; D046911:Macromolecular Substances; D011524:Protoporphyrins; C028025:protoporphyrin IX; D014805:Vitamin B 12