Eur. Phys. J. D 34, 315-319 (2005)
https://doi.org/10.1140/epjd/e2005-00166-9

Structures and reactions of hydrated biomolecular cluster ions

¹ Faculty of Science, Yokohama City University, Yokohama 236-0027, Japan
² Department of Chemistry, Faculty of Science, Kobe University, Kobe 657-8501, Japan

Corresponding author: ^a nonose@yokohama-cu.ac.jp

Received: 6 September 2004
Published online: 13 July 2005

Abstract

Photo-induced reactions and metastable decompositions of cluster ions containing glycine, tryptophan, tryptophanylglicine and [Fe(III)-protoporphyrin]⁺ (hemin ions solvated with water molecules are studied with electrospray ionization (ESI). The ESI ion source is improved to produce hydrated biomolecular cluster ions. Metastable decompositions of the hydrated clusters following primary mass selection are measured to determine the incremental solvent binding energies for the clusters by using evaporative ensemble model. From these experimental findings, stability of the cluster ions is discussed in terms of delocalization of ionic charges. We also measure the photodissociation yields of mass-selected water clusters containing hemin⁺ ions at 355 and 532 nm. The mass spectra of photofragments show the -cleavage of carboxymethyl groups in addition to the evaporation of solvent molecules.