Fundamental aspects concerning the inter and intramolecular properties of association complexes of metals and molecules of biolooical interest are not yet fully understood. The study of their structures and dynamics is an important research field for applications in chemistry and pharmacology. Information on their intrinsic properties can be gathered by studying isolated molecules and their complexes in a solvent-free environment, which permits a comparison with high-level theoretical calculations. Most of the biological molecules have, however, extremely low vapor pressure and are thermally labile. Many efforts have been made to find new vaporization methods. Pulsed laser ablation (PLA) technique proved to be suitable to desorbe solid amino acids and nucleic bases and their complexes with metals, in neutral and ionized states, and to perform mass spectrometry in gas-phase. Here we report mass spectra of biomolecules complexed with metals, generated by laser ablation PLA-mass spectrometry, or ablation followed by supersonic expansion (REMPI). (C) 2003 Elsevier B.V. All rights reserved.