Laser femtosecond MPI mass spectroscopy of dye-labeled nucleotides

The laser multiphoton photoionization (MPI) mass spectroscopy technique was used to investigate the processes of photoionization and fragmentation of the nucleotides chemically bound to the label chromophore group. The results of experiments with nucleotide-coumarin complexes are presented. The experiments involved four nucleic acid bases-adenosine, cytosine, guanine, and thymine-bound to the coumarin 120 dye chromophore. To obtain the mass spectra of the model compounds, use was made of 300-fs laser pulses at 308 nm. The results obtained were compared with the mass spectra resulting from the irradiation of the samples with 15-ns pulses at 266 or 355 nm. The mass spectra obtained are shown and discussed