title: Cluster secondary ion mass spectrometry imaging of interfacial reactions of TiO2 microspheres embedded in ionic liquids.
abstract: BACKGROUND
  Our goal is to develop protocols for the elucidation of the identity and structure of reaction products embedded in a reaction medium. Results should find significance in a variety of disciplines ranging from the study of biological cells and tissues, to the steps associated with the functionalization of nanoparticles.
  
  
  METHODS
  We utilize cluster secondary ion mass spectrometry (cluster-SIMS) to acquire three-dimensional (3D) information about 5-30 µm TiO2 microspheres imbedded into an ionic liquid. The method allows molecular depth profiling with submicron spatial resolution and depth profiling with a resolution of several tens of nanometers. The ionic liquid matrix enshrouds the spheres, allowing them to be introduced into the vacuum environment of the mass spectrometer.
  
  
  RESULTS
  The results provide 3D chemical information about these microspheres as they are synthesized by interfacial sol-gel reactions. We show that with 40 keV C60 (+) , it is possible to erode through the reaction medium and map the distribution of those embedded TiO2 microspheres. Moreover, we demonstrate that it is possible to monitor surface modification of the particles and, via ion beam drilling, elucidate their internal structure.
  
  
  CONCLUSIONS
  Using cluster-SIMS imaging, we are able to elucidate the identity and structure of reaction products embedded in a reaction medium, a problem of long-standing interest for materials characterization. With this strategy, we have provided a new approach that may be especially useful for the characterization of biological tissue and cells within the vacuum confines of the mass spectrometer. Copyright © 2015 John Wiley & Sons, Ltd.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA.
authors.forename: Kan
authors.initials: K
authors.lastname: Shen
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA.
authors.forename: Jay G
authors.initials: JG
authors.lastname: Tarolli
authors.affiliation: Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Winograd
mesh_terms: D003952:Diagnostic Imaging / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D052578:Ionic Liquids / Q000737:chemistry*; D008863:Microspheres; D018629:Spectrometry, Mass, Secondary Ion / Q000295:instrumentation* / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; C009495:titanium dioxide; D014025:Titanium