Identification and analysis of polypeptides by electrospray ionization tandem mass spectrometry

Identification of three polypeptides prepared by solid-phase synthesis using electrospray ionization mass spectrometry is reported. Molecular weights of the polypeptides were determined firstly by full-scan mass spectrometry, then fragmentation ions were obtained by selecting [M + H] (+) or [M + 2H](2+) ion using tandem mass spectrometry (MS/MS), the sequence of the polypeptides was confirmed by using complementary y ion and b ion method. The method was further validated by literature data, and it is simple, speed and practical.