Laser desorption is used to volatilize explosive materials for analysis by ion mobility/mass spectrometry measurements. The laser desorption is performed at relatively low power (< 107 W/cm2) so that mainly neutrals are produced, which are subsequently ionized by 63Ni-β-source induced ion-molecule reactions at atmospheric pressure. Atmospheric pressure ionization, together with the soft vaporization method, produces relatively simple spectra of the explosives investigated, yielding ions that are very characteristic of each molecule for identification. The technique has great potential for high sensitivity based upon the combination of complete laser vaporization of the sample and the API method, which is an extremely efficient form of ionization for these molecules with high electron affinities.
Ambient Pressure Laser Desorption—Chemical Ionization Mass Spectrometry for Fast and Reliable Detection of Explosives, Drugs, and Their Precursors