title: Commercial silicon-on-insulator (SOI) wafers as a versatile substrate for laser desorption/ionization mass spectrometry.
abstract: We report here that a commercial silicon-on-insulator (SOI) wafer offers an opportunity for laser desorption/ionization (LDI) of peptide molecules, which occurs directly from its flat surface without requiring special surface preparation. The LDI-on-SOI exhibits intact ionization of peptides with a good detection limit of lower than 20 fmol, of which the mass range is demonstrated up to insulin with citric acid additives. The LDI process most likely arises from laser-induced surface heating promoted by two-dimensional thermal confinement in the thin Si surface layer of the SOI wafer. As a consequence of the thermal process, the LDI-on-SOI method is also capable of creating post-source decay (PSD) of the resulting peptide LDI ions, which is suitable for peptide sequencing using conventional TOF/TOF mass spectrometry.
authors.affiliation: Center for Nano-Bio Technology, Korea Research Institute of Standards and Science, Daejeon, 305-340, Republic of Korea.
authors.forename: Shin Hye
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeongkwon
authors.initials: J
authors.lastname: Kim
authors.forename: Dae Won
authors.initials: DW
authors.lastname: Moon
authors.forename: Sang Yun
authors.initials: SY
authors.lastname: Han
mesh_terms: D019343:Citric Acid / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D010455:Peptides / Q000032:analysis / Q000737:chemistry; D012825:Silicon / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods*
chemical_list: D007477:Ions; D010455:Peptides; D019343:Citric Acid; D012825:Silicon