Mass resolution in time-of-flight mass spectrometers with reflectors
AssigneeBruker-Franzen Analytik GmbH
InventorsArmin Holle, Claus Koster, Jochen Franzen
Life of this patent
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Abstract
A method for the high resolution analysis of analyte ions in a time-of-flight mass spectrometer. The method consists of the generation of an intermediate time-focus plane for ions of a certain mass at a location between an ion source and an ion reflector, and then using the ion reflector to temporally focus the ions of equal mass and differing velocities which pass this plane at the same time onto a detector. For time-of-flight mass spectrometers with an ion selector, the ion selector is particularly favorable location for this intermediate plane with time focus; and with a collision cell for the collision fragmentation of the ions, the collision cell is a particularly favorable location.
Claims14
Method for the high resolution analysis of analyte ions in a time-of-flight mass spectrometer with an energy-focusing ion reflector, comprising the steps of
- (a) ionizing analyte molecules on a support electrode by pulsed laser desorption,
- (b) delaying the acceleration of the ions with respect to the laser pulse, so that all ions which leave an ion source with the same ratio of mass to charge experience time-focusing at a spatially fixed time-focus plane in spite of their different velocities,
- (c) adjusting this time-focus plane, by selection of time lag and acceleration field strength of the delayed acceleration, at a fixed location between the ion source and the reflector, and
- (d) focusing ions of equal mass, which simultaneously leave this time-focus plane, onto the detector by adjustment of the reflector potentials, so that they arrive at the same time, in spite of their different velocities.
Method for the high resolution analysis of sample ions in a time-of-flight mass spectrometer with an energy-focusing ion reflector, with ionization of sample molecules by laser desorption, and with delayed acceleration of the ions so that all ions which leave the ion source with the same ratio of mass to charge, experience time-focusing at a spatially fixed time-focus plane in spite of their different velocities, comprising the steps of
- (a) adjusting this time-focus plane, by selection of time lag and voltage drop of the delayed acceleration method, at a fixed location between the ion source and the reflector, and
- (b) focusing ions of equal mass, which simultaneously leave this time-focus plane, onto the detector by adjustment of the reflector potentials, so that they arrive at the same time, in spite of their different velocities.
Dependencies are inferred from the claim text.