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US 6,639,212 B1Granted
Method for separation of isomers and different conformations of ions in gaseous phase
AssigneeNational Research Council of Canada
InventorsRoger Guevremont, Randy Purves, David Barnett
Life of this patent
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Abstract
The present invention relates to a method of separating ions having the same mass to charge ratio but different ion mobility characteristics, based on the ion focussing principles of high field asymmetric waveform ion mobility spectrometry. Isomers including gas-phase molecular anions of the amino acids leucine and isoleucine are separable by the method of the present invention. Identification of different conformers of ions at the same charge state, including conformers present at certain charge states of the protein bovine ubiquitin, is also possible using the method of the present invention.
Claims57
A method for identifying ions having substantially the same mass to charge ratio but having different ion mobility characteristics, comprising the steps of:
- a) providing at least one ionization source of ions;
- b) providing an analyzer region defined by a space between at least first and second spaced apart electrodes, said analyzer region being in communication with a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said ions into said analyzer region through said ion inlet;
- c) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- d) setting said asymmetric waveform voltage;
- e) varying said direct current compensation voltage and measuring resulting transmitted ions at said ion outlet, so as to produce a compensation voltage scan for said transmitted ions;
- and
- f) identifying peaks in said compensation voltage scan.
4 more elements
A method for identifying constitutional isomers, comprising the steps of:
- a) providing at least one ionization source of at least one constitutional isomer;
- b) providing an analyzer region defined by a space between at least first and second spaced apart electrodes, said analyzer region being in communication with a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said ions into said analyzer region through said ion inlet;
- c) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- d) setting said asymmetric waveform voltage;
- e) varying said direct current compensation voltage and measuring resulting transmitted ions at said ion outlet, so as to produce a compensation voltage scan for said transmitted ions;
- and
- f) identifying peaks in said compensation voltage scan corresponding to a constitutional isomer.
4 more elements
A method for separating one of leucine ions and isoleucine ions from a gaseous mixture of leucine and isoleucine ions, comprising the steps of:
- a) providing a solution of leucine and isoleucine;
- b) producing a gaseous mixture of leucine and isoleucine ions from said solution of leucine and isoleucine ions;
- c) providing an analyzer region defined by a space between at least first and second spaced apart electrodes, said analyzer region being in communication with a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said leucine and isoleucine ions into said analyzer region through said ion inlet;
- d) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- e) setting said asymmetric waveform voltage;
- and
- f) setting said direct current compensation voltage to separate one of said leucine and isoleucine ions from said ion mixture.
4 more elements
A method for identifying different conformers, comprising the steps of:
- a) providing at least one ionization source for producing a sample of different conformers;
- b) providing an analyzer region defined by a space between at least first and second spaced apart electrodes, said analyzer region being in communication with a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said sample into said analyzer region through said ion inlet;
- c) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- d) setting said asymmetric waveform voltage;
- e) varying said direct current compensation voltage and measuring resulting transmitted ions at said ion outlet, so as to produce a compensation voltage scan of said transmitted ions;
- and
- f) identifying peaks in said compensation voltage scan corresponding to different conformers.
4 more elements
A method for identifying and/or separating one isomer from a mixture including two isomers, comprising the steps of:
- a) providing at least one ionization source for producing ions including two isomers;
- b) providing an analyzer region defined by a space between at least a first and second spaced apart electrodes, said analyzer region being in communication with at least one of each of a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said ions into said analyzer region through said ion inlet;
- c) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- d) setting said asymmetric waveform voltage in order to effect a difference in net displacement between said two isomers in the time of one cycle of said applied asymmetric waveform voltage;
- e) varying said direct current compensation voltage to compensate for some of the displacement of one of said two isomers, said displacement resulting from the applied asymmetric waveform voltage, and measuring resulting transmitted ions at said ion outlet, so as to produce a compensation voltage scan for said transmitted ions;
- and,
- f) identifying at least one peak in said compensation voltage scan corresponding to only one of said two isomers.
4 more elements
A method for identifying and/or separating different conformers, comprising the steps of:
- a) providing at least one ionization source for producing a sample including different conformer ions of a same compound;
- b) providing an analyzer region defined by a space between at least a first and second spaced apart electrodes, said analyzer region being in communication with at least one of each of a gas inlet, a gas outlet, an ion inlet and an ion outlet, and introducing said ions into said analyzer region through said ion inlet;
- c) applying an asymmetric waveform voltage and a direct current compensation voltage to at least one of said electrodes;
- d) setting said asymmetric waveform voltage in order to effect a difference in net displacement between said different conformer ions of a same compound in the time of one cycle of said applied asymmetric waveform voltage;
- e) varying said direct current compensation voltage to compensate for some of the displacement of one of said two conformer ions, said displacement resulting from the applied asymmetric waveform voltage, and measuring resulting transmitted ions at said ion outlet, so as to produce a compensation voltage scan for said transmitted ions;
- and,
- f) identifying at least one peak in said compensation voltage scan corresponding to only one of said different conformer ions.
4 more elements
Dependencies are inferred from the claim text.