Recording mass spectra to determine terminal sequences of biopolymers, used especially for protein sequencing, based on analysis of grandchild ions formed from fragment ions produced by ion-source decay

摘要

A method for recording mass spectra (MS) that contain information about the terminal sequences of a biopolymer (I), using a tandem mass spectrometer that has an ion source for ionization of (I) by matrix-assisted laser desorption, is new. Method for recording mass spectra (MS) that contain information about the terminal sequences of a biopolymer (I), using a tandem mass spectrometer that has an ion source for ionization of (I) by matrix-assisted laser desorption. The new feature is that one type of ISD (ion-source decay) fragmentation ions (Y) of (I), generated by the high laser energy density in the source, is subjected to further fragmentation (collisionally induced, surface-induced, photon-induced or laser-induced) and the resulting 'grandchild' ions (X) are measured as MS. Independent claims are also included for: (1) similar method where (X) are generated in the first spectrometer and analyzed in the second spectrometer; and (2) method for determining terminal sequences of a protein by comparing (X) spectra of different IDS fragment ions from the same fragmentation series.