Ion mobility spectrometers with improved resolution
AssigneeGeneral Electric Company
InventorsAnthony Jenkins, William J. McGann
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Abstract
An apparatus is provided for detecting whether substances of interest are present in a sample of air. The apparatus includes a detector, such as an ion trap mobility spectrometer. The detector is operated at a high drift voltage and then is switched to a low drift voltage. Spectra are collected at the high and low field strengths and are compared with standard spectra at those strengths to determine whether materials of interest are present.
Claims15
An apparatus for detecting whether a substance of interest is present in a sample of air, comprising;
- an inlet for delivering the sample of air;
- an ion mobility detector in communication with the inlet and operable alternately at high and low drift voltage levels for detecting whether the substance of interest is present;
- at least one source of high voltage for applying a high drift voltage to the detector;
- and
- a controller communicating with the detector and the source of high voltage for selectively reducing the voltage to the detector to a low drift voltage.
An apparatus for detecting whether substances of interest are in any of plurality of samples of air, said apparatus comprising;
- an inlet for receiving one of the samples of air;
- a reaction chamber communicating with the inlet and operative for ionizing molecules in the reaction chamber;
- a drift tube in communication with the reaction chamber;
- a collector electrode in the drift tube at a location spaced from the reaction chamber;
- at least one field-defining electrode in the drift tube between the reaction chamber and the collector electrode;
- at least one source of voltage for applying a drift voltage across the field-defining electrode;
- and
- a controller for selectively switching between a high drift voltage and a low drift voltage for alternating between a high field strength and a low field strength in the drift tube.
A method for testing samples of air to determine whether any of the samples of air contain a substance of interest, the method comprising;
- delivering one of the samples of air to an ion mobility detector;
- operating the detector at a first drift voltage level to test for a presence of the substance of interest in the sample;
- and
- operating the detector at a second drift voltage level to test for the presence of the substance of interest.
Dependencies are inferred from the claim text.