APPLICATIONS OF LASER DESORPTION MASS SPECTROMETRY.

The laser desorption technique can be used for the mass spectral analysis of nonvolatile/thermally labile compounds such as peptides, oligosaccharides, glycolipids, etc. In our laboratory a laser desorption time-of-flight mass spectrometer has been used for structural confirmation of several glucuronic acid conjugates, synthesized by an immobilized-enzyme mediated technique. Laser desorption spectra of several small peptides produce both C-terminal and N-terminal fragments. The molecular ions are formed by cationization (alkali ion attachment) and the alakali ion is generally found on the C-terminal fragments, suggesting a ionization/fragmentation scheme similar to that observed by chemical ionization.