Differential mobility spectrometry method
First Claim
1. A method of operating a system comprising a differential mobility spectrometer, the method comprising:
- (a) injecting a stream of ions into a differential mobility spectrometer during a first duration, the stream of ions containing or suspected of containing an ion species of interest;
(b) determining a compensation voltage apex for the ion species of interest in the differential mobility spectrometer, wherein the compensation voltage apex represents a nominal optimum for transmission of the ion species of interest based on operating conditions of the differential mobility spectrometer that are provided by a look-up table or wherein the compensation voltage apex for the ion species of interest is determined based on a theoretical optimum transmission compensation voltage;
(c) varying the compensation voltage applied to the differential mobility spectrometer over a predetermined range about the determined compensation voltage apex during said first duration;
(d) detecting the ion species of interest transmitted by the differential mobility spectrometer during said first duration and generating a composite spectra of the ion species of interest.
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Accused Products
Abstract
Methods and systems are provided herein for varying the CoV about a nominal CoV-apex while monitoring the ion of interest corresponding to the nominal CoV-apex as it is transmitted by a DMS. In various aspects, the CoV can be swept or stepped across a series of values during the injection of ions into the DMS such that a composite spectra of the ion of interest transmitted by the DMS (or its product ions following one or more stages of fragmentation) can be generated so as to include the transmission of the particular ion at a CoV with optimum sensitivity (i.e., if distinct from the CoV-apex), thereby improving the robustness, accuracy, and/or selectivity during experimental conditions relative to known DMS techniques, which typically used a fixed CoV value for each ion of interest.
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Citations
16 Claims
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1. A method of operating a system comprising a differential mobility spectrometer, the method comprising:
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(a) injecting a stream of ions into a differential mobility spectrometer during a first duration, the stream of ions containing or suspected of containing an ion species of interest; (b) determining a compensation voltage apex for the ion species of interest in the differential mobility spectrometer, wherein the compensation voltage apex represents a nominal optimum for transmission of the ion species of interest based on operating conditions of the differential mobility spectrometer that are provided by a look-up table or wherein the compensation voltage apex for the ion species of interest is determined based on a theoretical optimum transmission compensation voltage; (c) varying the compensation voltage applied to the differential mobility spectrometer over a predetermined range about the determined compensation voltage apex during said first duration; (d) detecting the ion species of interest transmitted by the differential mobility spectrometer during said first duration and generating a composite spectra of the ion species of interest. - View Dependent Claims (2)
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3. An apparatus for analyzing ions comprising:
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an ion source configured to generate ions from a sample containing or suspected of containing an ion species of interest; a differential mobility spectrometer configured to receive the plurality of ions from the ion source and transmit one or more ions species based on the differential mobility of the ion species therein; a detector for detecting the ion species transmitted by the differential mobility spectrometer; and a controller operatively coupled to the ion source, the differential mobility spectrometer, and the detector, and configured to; cause the ion source to inject a stream of ions into the differential mobility spectrometer during a first duration; determine a compensation voltage apex for the ion species of interest in the differential mobility spectrometer, wherein the compensation voltage apex represents a nominal optimum for transmission of the ion species of interest based on operating conditions of the differential mobility spectrometer that are provided by a look-up table or wherein the compensation voltage apex for the ion species of interest is determined based on a theoretical optimum transmission compensation voltage; vary the compensation voltage applied to the differential mobility spectrometer over a predetermined range about the determined compensation voltage apex during said first duration; and detect the ion species of interest transmitted by the differential mobility spectrometer during said first duration and generating a composite spectra of the ion species of interest. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification