Identification of samples using a multi pass or multi reflection time of flight mass spectrometer

摘要

A multi reflection time of flight (MRTOF) mass spectrometer (12) And method for identifying a sample is disclosed. Sample ions are generated at an ion source (15). The MRTOF is a closed mirror arrangement with first and second opposed ion mirrors (20, 20) on an axis of reflection (XX). The MRTOF (12) also includes a bidirectional ion deflector (50) on that axis (XX). The deflector (50) deflects ions onto the reflection axis as a short pulse at time to zero where they oscillate multiple times, separating in time of flight according to ion m/z. At a later time t, ions travelling in both directions along the axis (XX) are ejected out of the MRTOF (12) by the bidirectional deflector (50) to an ion detector arrangement (55). The separation of ions in time of flight allows a fingerprint of a biological sample to be produced by the detector arrangement (55) without the need to assign a mass to each peak. Comparison with a library of fingerprints permits identification.