Time- of flight mass spectrometers for improving resolution and mass employing an impulse extraction ion source
AssigneeThe Johns Hopkins University
InventorTimothy J. Cornish
Life of this patent
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Abstract
A miniature time-of-flight mass spectrometer (TOF-MS) and method for increasing the collection efficiency of laser-desorbed ions in a miniature time-of-flight mass spectrometer (TOF-MS) is provided. The method provides a laser pulse generated by an ionization extraction device within the TOF-MS; maintains a sample plate potential at a ground level for a fixed delay period of about 50 ns; and uses a high voltage switch to sharply increase the sample plate potential up to 10 kV/mm.
Claims8
A device for increasing the mass resolution of laser-desorbed MALDI ions across a wide mass range, said device comprising:
- an ionization extraction device having an unobstructed central chamber for guiding ions therethrough;
- a microchannel plate detector assembly having a channel extending through at least a portion of the assembly;
- a flexible circuit-board reflector, wherein said channel is aligned with a central axis of said ionization extraction device and a central axis of said reflector;
- and
- a voltage switch for increasing a sample plate potential sharply.
An ionization extraction device for use in a TOF-MS comprising:
- a housing defining an unobstructed central chamber for guiding ions therethrough;
- a first region within the central chamber for accelerating ions for creating an ion acceleration/extraction field measuring up to 10 kV/mm for accelerating the ions;
- a second region within the central chamber in proximity to the first region for de-accelerating the ions entering therein;
- a third region within the central chamber for causing the ions to disperse and having an electric field measurement of about 0 kV/mm;
- a laser for providing a laser pulse for ion creation in a source region;
- and
- a voltage switch for increasing a sample plate potential sharply to create an ion acceleration/extraction field near the sample plate of up to 10 kV/mm after a delay period of about 50 ns.
A method for increasing the mass resolution of laser-desorbed ions in a TOF-MS, said method comprising the steps of:
- providing an ionization extraction device within the TOF-MS, the ionization extraction device having an unobstructed central chamber having a first region and a second region;
- creating an ion acceleration/extraction field measuring up to 10 kV/mm within the first region;
- creating ions in the first region by one of laser ablation and matrix assisted laser desorption/ionization (MALDI);
- aligning a central axis of the ionization extraction device with a tubular channel of a microchannel plate detector assembly of the TOF-MS;
- aligning a central axis of the ionization extraction device with a central axis of a circuit-board reflector of the TOF-MS;
- providing a laser pulse for ion creation in a source region;
- maintaining a sample plate potential at a ground level for a delay period;
- and
- increasing said sample plate potential sharply after the delay period.
Dependencies are inferred from the claim text.