MATRIX-ASSISTED LASER DESORPTION OF NEUTRAL ORGANIC-MOLECULES

Results of initial investigations of matrix-assisted laser desorption (LD) of neutral molecules are presented. The investigations were performed using gramicidine D as the test molecule, since both the wavelength-dependent LD behaviour and the ionization and fragmentation behaviour of the pure material had been studied previously. Comparisons between previously reported results for the pure compound and the matrix mixtures used in these studies are made. The results show that, whereas no signal could be observed from the pure sample material at nonresonant desorbing wavelengths, addition of a strongly absorbing matrix to the sample initiated LD of abundant intact neutral sample molecules. The results are discussed in the light of previous studies of the LD mechanism and support an explosive, mechanically driven model for the LD process.