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US 4,066,894 AGranted
Positive and negative ion recording system for mass spectrometer
AssigneeUniversity of Virginia
InventorsDonald F. Hunt, George C. Stafford, Jr.
Life of this patent
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AssigneeUniversity of Virginia
InventorsDonald F. Hunt, George C. Stafford, Jr.
Estimating the term…
A method and an apparatus are disclosed for adapting a conventional quadrupole mass spectrometer to substantially simultaneously produce and record both positive and negative ions. The apparatus includes a control circuit for rapidly switching the repeller, source and lens electrodes of a quadrupole mass spectrometer between positive and negative potentials. This switching of the potentials, along with the selection of appropriately favorable ionization conditions, permits the generation of suitable streams of positive and negative ions. A dual electron multiplier detector is used for separately sensing the positive and negative ions transmitted through the quadrupole mass spectrometer. The disclosed method and apparatus are particularly suitable for obtaining accurate mass measurements using a quadrupole mass spectrometer.
A method of generating and monitoring positive and negative ions substantially simultaneously using a quadrupole mass spectrometer having an ion generator with repeller, source and lens electrodes, and a quadrupole filter, comprising the steps of:
An apparatus for enabling a quadrupole mass spectrometer, having an ion generator with repeller, source and lens electrodes, and a quadrupole filter, to effectively simultaneously generate and monitor both positive and negative ions, comprising:
Dependencies are inferred from the claim text.