title: A dual cryogenic ion trap spectrometer for the formation and characterization of solvated ionic clusters.
abstract: A new experimental approach is presented in which two separate cryogenic ion traps are used to reproducibly form weakly bound solvent clusters around electrosprayed ions and messenger-tag them for single-photon infrared photodissociation spectroscopy. This approach thus enables the vibrational characterization of ionic clusters comprised of a solvent network around large and non-volatile ions. We demonstrate the capabilities of the instrument by clustering water, methanol, and acetone around a protonated glycylglycine peptide. For water, cluster sizes with greater than twenty solvent molecules around a single ion are readily formed. We further demonstrate that similar water clusters can be formed around ions having a shielded charge center or those that do not readily form hydrogen bonds. Finally, infrared photodissociation spectra of D2-tagged GlyGlyH(+)⋅(H2O)1-4 are presented. They display well-resolved spectral features and comparisons with calculations reveal detailed information on the solvation structures of this prototypical peptide.
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Marsh
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Voss
authors.affiliation: Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
authors.forename: Etienne
authors.initials: E
authors.lastname: Garand
mesh_terms: D000096:Acetone / Q000737:chemistry*; D006033:Glycylglycine / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry / Q000295:instrumentation*; D000432:Methanol / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D012995:Solubility; D013055:Spectrophotometry, Infrared; D014867:Water / Q000737:chemistry*
chemical_list: D007477:Ions; D011522:Protons; D014867:Water; D006033:Glycylglycine; D000096:Acetone; D000432:Methanol