title: Mass spectrometry of oligopeptides in the presence of large amounts of alkali halides using desorption/ionization induced by neutral cluster impact.
abstract: Oligopeptides in the presence of large amounts of salt were desorbed and ionized using desorption/ionization induced by neutral clusters (DINeC) for further analysis by means of mass spectrometry (MS). Using oligopeptides in alkali halide solutions as a model system, DINeC was shown to yield clear and fragmentation free mass spectra of the biomolecules even from environments with a large excess of salt. The results were traced back to a phase separation between salt and biomolecules during sample preparation. The ratio between alkali metal complexes [M+A](+) and bare biomolecules [M+H](+) was controlled using different preparation schemes. DINeC was applied to the products of a tryptic digest of bovine serum albumin in the presence of sodium chloride; the results of a mass fingerprint analysis did not show a major difference for the spectra with and without salt in the original solution. The metal-ion/peptide interaction was further investigated by means of tandem-MS.
authors.affiliation: Institut für Angewandte Physik, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Portz
authors.affiliation: Fakultät Angewandte Naturwissenschaften, Hochschule Esslingen, Kanalstr. 33, D-73728 Esslingen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Baur
authors.affiliation: Bruker Daltonik GmbH, Fahrenheitstr. 4, D-28359 Bremen, Germany.
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Gebhardt
authors.affiliation: Institut für Angewandte Physik, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, D-35392 Giessen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Dürr
mesh_terms: D013058:Mass Spectrometry / Q000379:methods*; D009842:Oligopeptides / Q000032:analysis*; D012710:Serum Albumin, Bovine / Q000378:metabolism*; D012965:Sodium Chloride; D014357:Trypsin / Q000378:metabolism*
chemical_list: D009842:Oligopeptides; D012710:Serum Albumin, Bovine; D012965:Sodium Chloride; D014357:Trypsin