A tandem time-of-flight (ToF) mass spectrometer consisting of a multi-turn ToF and a quadratic-field ion mirror has been designed and constructed. The instrument combines the unique capabilities of both ToF instruments, namely high-resolution and monoisotopic precursor ion selection from the multi-turn ToF and temporal focus for fragment ions with different kinetic energies from the quadratic-field mirror. The first tandem mass spectra for this unique combination of ToF systems are presented.
On de novo interpretation of tandem mass spectra for peptide identification