Patent ID: 7157701

Claim:
A method for high-resolution analysis of analyte ions in a time-of-flight mass spectrometer (TOF-MS), comprising: a) applying potentials across an acceleration region and an ion mirror; b) ionizing analyte molecules in a source/extraction region; c) focusing ions of like charge-to-mass ratio onto an ion detector by the steps comprising: i) waiting a predetermined delay time following ionization; ii) generating a time-dependent extraction potential across the source/extraction region; iii) decreasing the strength of the time-dependent extraction potential according to a predetermined continuous function so as to spread out the energy distribution of the ions; iv) passing the ions out of the source/extraction region; v) passing the ions through the acceleration region; vi) passing the ions through a first field free drift region; vii) passing the ions through the ion mirror to compensate for the energy distribution of the ions; and viii) passing the ions through a second field free drift region; d) detecting the ions as they strike the ion detector; e) having the like charge-to-mass ratio ions generated in ionization step b) arrive at the ion detector at a time that is substantially independent of: i) initial ion velocity at the beginning of the ion extraction; and ii) initial position of the ion in the source/extraction region at the beginning of ion extraction; and f) achieving high mass resolution over a broad range of masses without altering the magnitude of the applied potentials across the acceleration region and ion mirror, and the time dependence or magnitude of the time-dependent extraction potential, and not changing the physical dimensions of the TOF-MS.