Lock mass ions for use with derivatized peptides for de novo sequencing using tandem mass spectrometry

摘要

Multiple derivatization by chemical reactions of analytes for mass spectrometry is disclosed. The derivatizations enhance the use of MS techniques for analyzing protein samples, particularly when the sequence of a polypeptide is determined by tandem MS/MS. Accurate mass analysis techniques are described for use in sequencing polypeptides, together with the use of sequencing data in protein analysis. An apparatus and method for calibrating a mass spectrometer by internally introducing calibration masses at a post-source stage of the mass spectrometer is also provided. Lock mass ions mix with the derivatized polypeptide analyte ions prior to mass analysis.