Abstract: | A laser desorption Fourier transform mass spectrometric (LD/FTMS) method that uses both positive and negative ion LD/FT mass spectra obtained with collision-activated dissociation has been developed for analysis of oligopeptides. The technique is demonstrated using the model compound gramicidin D, for which the correct sequence is derived using only LD/FTMS information. Different relationships between positive and negative ion spectra are found for linear and cyclic oligopeptides. |