| 摘要 |
The invention relates to the acquisition of mass spectra of biopolymers, especially of proteins, in tandem mass spectrometers with matrix-assisted laser desorption ionization (MALDI), for the examination or determination of terminal sequence patterns. A first generation of fragment or daughter ions of a biopolymer are generated by so called in-source fragmentation/decay (ISF/ISD). Granddaughter ions, obtained by further fragmentation of a selected type of daughter ion, are subsequently detected and measured. The further fragmentation may be by means of collisionally-induced dissociation (CID), surface-induced decomposition (SID), photon-induced dissociation (PID), or metastable decay/laser-induced decomposition (LID). Preferably the tandem mass spectrometer is a tandem time-of-flight mass analyser (TOF/TOF-MS). The invention enables the determination of the terminal sequences which are otherwise difficult to measure. |
