| Abstract
| - Laser desorption/ionization from a single-crystal siliconsurface was performed using a laser operating in the 3-μmregion of the mid-infrared. Analyte molecules up to 6 kDawere ionized with no added matrix. As with ultravioletdesorption/ionization from porous silicon (DIOS), IRlaser desorption from silicon does not produce matrix ionsthat can interfere with analysis of low-mass analytes.However, in contrast to UV DIOS, silicon porosity orroughness is not required for ionization using an IR laser.Mass spectra were obtained in the wavelength rangebetween 2.8 and 3.5 μm, which is consistent with energyabsorption by a hydrogen-bonded OH group. A mechanism based on desorption of adsorbed solvent moleculesis postulated.
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