Open AccessOn the photoionization of large molecules
Author(s) -
C. H. Beckercor,
K. J. Wufn
Publication year - 1995
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/1044-0305(95)00472-p
Subject(s) - photoionization , chemistry , mass spectrometry , mass spectrum , ionization , molecule , excited state , spectral line , analytical chemistry (journal) , photochemistry , ion , atomic physics , organic chemistry , chromatography , physics , astronomy
There is no apparent limit to the size of a molecule for which photoionization can occur. It is argued that it is difficult to obtain useful photoionization mass spectra of peptides (above ∼ 2000 u), proteins, and oligonucleotides, because of the high internal energy of these polar molecules as a result of the desorption event and because vibrationally excited radical cations readily fragment. Evidence to support this hypothesis is presented from the 118-nm single-photon ionization (SPI) mass spectra of the cyclic decapeptide gramicidin S and of fullerenes, from null SPI results with the linear peptides substance P and gramicidin D and oligonucleotides, and from a variety of data found in the literature. The literature data include mass spectra from jet-cooled peptides, perfluorinated polyethers, collisional ionization of small neutral peptides, and the ultraviolet photoelectron spectroscopy of polymeric solids.