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Title: The use of nanomaterials for mass spectrometry can be uplifting for analyte detection

Surface-Assisted Laser Desorption Ionization (SALDI) involves desorbing and ionizing analyte molecules from a nanoporous substrate by laser irradiation for detection in a mass spectrometer. In this work experiments were designed to better understand the mechanisms governing desorption and ionization for Desorption Ionization On Silicon (DIOS), a variant of SALDI which uses porous silicon (pSi) as a substrate. Experiments are also reported for other nanoporous semiconducting materials (WO{sub 3}, TiO{sub 2}) which exhibit very similar behaviors; specifically, that both protonated analyte ions and analyte radical cations can be generated with relative intensities that depend on the position of the incident laser focus relative to substrate surface. While thermal desorption appears to be important, preliminary evidence suggests that the ionization mechanism leading to protonated analytes involves in part electrons and holes formed when photoexciting the substrate above its electronic band gap, and the presence of defect states within the band gap. Radical cation formation appears to be driven in part by electron transfer due to the large electron affinity of each substrate used in this work.
Authors:
;  [1]
  1. University of Victoria Department of Chemistry, P.O. Box 3065, STN CSC Victoria, BC V8W 3V6 (Canada)
Publication Date:
OSTI Identifier:
22265921
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1590; Journal Issue: 1; Conference: International conference on electronic, photonic, plasmonic and magnetic properties of nanomaterials, London (Canada), 12-16 Aug 2013; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; DESORPTION; DETECTION; ELECTRON TRANSFER; IONIZATION; LASER RADIATION; LASERS; MASS SPECTROMETERS; MASS SPECTROSCOPY; NANOSTRUCTURES; SILICON; SUBSTRATES; TITANIUM OXIDES; TUNGSTATES; TUNGSTEN OXIDES