Fast atom bombardment and tandem mass spectrometry of synthetic peptides and byproducts.

Mass spectrometry is a very powerful technique in the rapid determination of the structure of peptides. Synthetic peptides may be analyzed fully protected and partially or completely deprotected. Often, the molecular weight alone, readily obtained by fast atom bombardment mass spectrometry, is sufficient to establish the nature of the product and whether it is the expected one. Tandem mass spectrometry can be used to identify unexpected reaction products which sometimes form during removal of protecting groups, the incomplete removal of such groups, as well as to distinguish between structural isomers.