Abstract
The laser spray developed in our laboratory was applied to the analysis of biological samples. Because a 10.6 mm laser excites hydrogen bonds of water solvent, vaporization of aqueous samples takes place effectively by the laser irradiation. This makes laser spray superior to ESI for aqueous sample solution. The sensitivity of laser spray is approximately ten times higher than that of ESI for a large number of samples. The increase of signal intensities for both laser spray and ESI was observed by the addition of ammonium acetate to the sample solutions. This result was interpreted by an electrical double layer model proposed by Enke et al. The concentration of analyte ions in laser-sprayed droplets is estimated to be 10 times higher than that in the electrosprayed droplets. Noncovalent complexes were dissociated selectively to subunits by laser irradiation without dissociating the covalent bonds.
