Patent ID: 7838824

Claim:
A method for multiplex operation of a tandem time-of-flight mass spectrometer comprising: (a) selecting a predetermined set of ions with a first timed-ion-selector, said set of ions comprising one or more precursor ions and their associated fragment ions, wherein the masses of any two precursor ions of the predetermined set of ions differ by at least 1 percent in mass; (b) accelerating said predetermined set of ions and their associated fragment ions using a pulsed ion accelerator; (c) selecting a portion of the fragment ions associated with the predetermined set of ions with a second timed-ion-selector; (d) energizing the second timed-ion selector to transmit only a predetermined portion of a fragment ion spectrum to minimize overlap between fragment spectra from different precursor ions; (e) transmitting the predetermined portion of the fragment ion spectrum to an ion detector; and (f) detecting a fragment ion spectra with the ion detector.