Development of a tandem time-of-flight mass spectrometer with an electrospray ionization ion source.

A new tandem time-of-flight mass spectrometer with an electrospray ionization ion source 'ESI-TOF/quadTOF' was designed and constructed to achieve the desired aim of structural elucidation via high-energy collision-induced dissociation (CID), and the simultaneous detection of all fragment ions. The instrument consists of an orthogonal acceleration-type ESI ion source, a linear TOF mass spectrometer, a collision cell, a quadratic-field ion mirror and a microchannel plate detector. High-energy CID spectra of doubly protonated angiotensin II and bradykinin were obtained. Several fragment ions such as a-, d-, v- and w-type ions, characteristic of high-energy CID, were clearly observed in these spectra. These high-energy CID fragment ions enabled confirmation of the complete sequence, including leucine-isoleucine determinations. It was demonstrated that high-energy CID of multiply protonated peptides could be achieved in the ESI-TOF/quadTOF.