title: Cationization of simple organic molecules by singly-charged Ag3+ cluster ions in matrix-assisted laser desorption/ionization mass spectrometry: metal cluster-molecule interactions.
abstract: It was found earlier that under matrix-assisted laser desorption/ionization (MALDI) conditions several organic compounds which produce adduct with silver ions, are also capable of forming adducts with Ag(3)(+) cluster ions under appropriate conditions. The Ag(3)(+) cluster ion can be in situ generated under the MALDI analysis conditions from silver trifluoroacetate cationization agent in the presence of organic MALDI matrices. In this article the fragmentation of a commercial plasticizer, a peracetylated isoflavone glycoside and a pyrazolylphenyl disulfide derivative cationized with silver ions and Ag(3)(+) cluster ions are compared. It was observed that the complexes of Ag(3)(+) are less fragmented than the corresponding adduct ions with Ag(+). The presumable fragmentation channel of [M + Ag(3)(+)] is the elimination of Ag(2) units from these complexes. No significant dissociation of [M + Ag(3)(+)], into M and Ag(3)(+) takes place, indicating a tight connection between the corresponding molecule and Ag(3)(+) cluster ion. However, with a compound carrying very labile groups, such as the pyrazolylphenyl disulfide derivative, intramolecular cleavages can occur prior to significant dissociation of the Ag(3)(+) cluster ion.
authors.affiliation: Department of Applied Chemistry, University of Debrecen, Debrecen, Hungary.
authors.forename: Sándor
authors.initials: S
authors.lastname: Kéki
authors.forename: Lajos
authors.initials: L
authors.lastname: Nagy
authors.forename: György
authors.initials: G
authors.lastname: Deák
authors.forename: Miklós
authors.initials: M
authors.lastname: Zsuga
authors.forename: László
authors.initials: L
authors.lastname: Somogyi
authors.forename: Albert
authors.initials: A
authors.lastname: Lévai