title: Mass Spectra and Yields of Intact Charged Biomolecules Ejected by Massive Cluster Impact for Bioimaging in a Time-of-Flight Secondary Ion Microscope.
abstract: Impacts of massive, highly charged glycerol clusters (≳10(6) Da, ≳ ± 100 charges) have been used to eject intact charged molecules of peptides, lipids, and small proteins from pure solid samples, enabling imaging using these ion species in a time-of-flight secondary ion microscope with few-micrometer spatial resolution. Here, we report mass spectra and useful ion yields (ratio of intact charged molecules detected to molecules sputtered) for several molecular species-two peptides, bradykinin and angiotensin II; two lipids, phosphatidylcholine and sphingomyelin; Irganox 1010 (a detergent); insulin; and rhodamine B-and show that useful ion yields are high enough to enable bioimaging of peptides and lipids in biological samples with few-micrometer resolution and acceptable signals. For example, several hundred molecular ion counts should be detectable from a 3 × 3 μm(2) area of a pure lipid bilayer given appropriate instrumentation or tens of counts from a minor constituent of such a layer.
authors.affiliation: Department of Chemistry & Biochemistry, Arizona State University , PO Box 1604, Tempe, Arizona 85287-1604, United States.
authors.forename: Jitao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Chemistry & Biochemistry, Arizona State University , PO Box 1604, Tempe, Arizona 85287-1604, United States.
authors.forename: Klaus
authors.initials: K
authors.lastname: Franzreb
authors.affiliation: Department of Chemistry & Biochemistry, Arizona State University , PO Box 1604, Tempe, Arizona 85287-1604, United States.
authors.forename: Sergei A
authors.initials: SA
authors.lastname: Aksyonov
authors.affiliation: Department of Chemistry & Biochemistry, Arizona State University , PO Box 1604, Tempe, Arizona 85287-1604, United States.
authors.forename: Peter
authors.initials: P
authors.lastname: Williams
mesh_terms: D005990:Glycerol / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D008853:Microscopy; D046032:Microscopy, Energy-Filtering Transmission Electron / Q000295:instrumentation*; D010455:Peptides / Q000737:chemistry*; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D007477:Ions; D008055:Lipids; D010455:Peptides; D005990:Glycerol