Sequence-specific fragmentation from oligopeptides using plasma-desorption mass spectrometry.

252Cf plasma-desorption mass spectrometry (PDMS) has been demonstrated to provide sequence-specific fragmentation for several oligopeptides. The nature of the fragment ions observed is generally similar to that observed using liquid secondary-ion mass spectrometry (LSIMS) and can be observed using less sample than LSIMS requires, but PDMS spectra are acquired at a lower resolution. In addition, the molecular weight of some of the oligopeptides studied exceeds that which is generally accepted as within the sequence range of LSIMS. The specific series of sequence ions that predominate in the PDMS spectra appear to be related to the amino acid compositions and sequences of the oligopeptides.