International Journal of Mass Spectrometry 225 (2003) 89–94 Short communication Gas-phase Cu + – and Ag + –glycine complexes produced with a new source Maria Massaouti a,b , Michalis Velegrakis a,∗ a Foundation for Research and Technology—Hellas, Institute of Electronic Structure and Laser, P.O. Box 1527, 711 10 Heraklion, Greece b Department of Chemistry, University of Crete, 711 10 Heraklion, Greece Received 31 May 2002; accepted 27 September 2002 Abstract A combination of the laser ablation of a metal target with an effusive amino acid oven and the free-jet expansion of helium is employed in order to produce gas-phase metal cation–amino acid complexes in a molecular beam. With this source, Cu + –glycine and Ag + –glycine complexes are formed through gas-phase reactions and are analyzed using a time-of-flight mass spectrometer. From the mass spectra we conclude that copper is dicoordinated while silver can attract up to four glycine molecules. © 2002 Elsevier Science B.V. All rights reserved. Keywords: Metal–amino acid complexes; Mass spectrometer; Glycine 1. Introduction The binding of metal ions to amino acids, peptides and proteins plays a very important role in biology. Metal ions in solutions with biomolecules cause a se- ries of chemical processes such as catalysis, electron transfer, O 2 transport, stabilization, etc. [1]. Further- more, metal ions play a very crucial role in organiz- ing three dimensional biological structures [2]. These phenomena originate from the ability of metal ions to bind preferentially to several bioligands, thus affect- ing strongly the structure of nucleic acids. In solution, there are many factors (e.g., pH) that influence the ∗ Corresponding author. Tel.: +30-810-391122; fax: +30-810-391318. E-mail address: vele@iesl.forth.gr (M. Velegrakis). structural properties of the nucleic acids and, therefore, investigations of these properties are very complicated. In contrast, studies on metal ion–biomolecule com- plexes in the gas phase provide valuable information, as the complexes are free molecules and therefore are not affected by local environment (solvent) that can stabilize or destabilize them. Thus, such gas-phase studies compared with the solution-phase ones, are very useful for understanding the role of metal ions in initiating biochemical processes. In the last few years, there has been an intensive effort in developing sources able to produce free complexes between metal ions and biomolecules. Fast atom bombardment (FAB) sources have been employed to produce metal ion–amino acid com- plexes [3]. In recent years, the matrix-assisted laser 1387-3806/02/$ – see front matter © 2002 Elsevier Science B.V. All rights reserved. PII S1387-3806(02)01020-5