TANDEM MASS SPECTROMETRY APPARATUS

摘要

Tandem mass spectrometry apparatus comprises a serial arrangement of an ion source (10), a first time-of-flight means (20, 80), a collision cell (40) to generate fragment ions and a second time-of-flight analyser (50). The second time-of-flight analyser comprises an ion mirror (51, 52) which is arranged to produce a quadratic field along or at an angle to the optical axis of the apparatus. The first time-of-flight analyser may comprise a sequential S configuration of toroidal or cylindrical electrostatic analysers (70) or may comprise two electrostatic lenses (80, 96) to either side of an ion mirror or may comprise an electrostatic lens (80). The first time-of-flight analysers thus comprise electrostatic field means for providing spatial focusing of ions in all three dimensions at or near the entrance to the ion mirror of the second time-of-flight analyser (50). The spatial focusing, concomitant with time focusing, is the essential requirement for the quadratic field mirror to give high resolution.