Apparatus and methods for ion separation, especially IMS, using an ion shutter
First Claim
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1. A method of controlling an ion shutter of an IMS cell, the method comprising:
- controlling a barrier voltage between a first shutter electrode and a second shutter electrode to open and close the shutter to allow ions of interest to pass through the shutter in a drift direction by varying the voltage of the first shutter electrode; and
varying the voltage of the second shutter electrode;
wherein the voltages of the first shutter electrode and the second shutter electrode are varied with respect to a spatially varying profile voltage of the IMS cell, the voltage of the first shutter electrode is controlled to match the profile voltage prior to opening of the shutter, and the first shutter electrode lies between a reaction region of the IMS cell and the second shutter electrode.
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Abstract
The disclosure relates to methods and apparatus for ion separation, for example using time of flight and ion mobility spectrometry. Ion shutters for use in IMS cells and to methods of operating them are also disclosed. The shutter includes a first shutter electrode and a second shutter electrode. A barrier voltage between these two electrodes is controlled to open and close the shutter to allow ions of interest to pass through the shutter in a drift direction. The control involves varying both: (a) the voltage of the first shutter electrode; and (b) the voltage of the second shutter electrode.
25 Citations
14 Claims
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1. A method of controlling an ion shutter of an IMS cell, the method comprising:
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controlling a barrier voltage between a first shutter electrode and a second shutter electrode to open and close the shutter to allow ions of interest to pass through the shutter in a drift direction by varying the voltage of the first shutter electrode; and
varying the voltage of the second shutter electrode;wherein the voltages of the first shutter electrode and the second shutter electrode are varied with respect to a spatially varying profile voltage of the IMS cell, the voltage of the first shutter electrode is controlled to match the profile voltage prior to opening of the shutter, and the first shutter electrode lies between a reaction region of the IMS cell and the second shutter electrode. - View Dependent Claims (2, 3)
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4. An IMS cell comprising:
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an ion shutter comprising a first shutter electrode and a second shutter electrode; a first shutter voltage provider circuit configured to vary the voltage of the first shutter electrode; and a second shutter voltage provider circuit configured to vary the voltage of the second shutter electrode, wherein the first shutter voltage provider circuit and the second shutter voltage provider circuit are configured to control a barrier voltage between the first shutter electrode and the second shutter electrode by varying the voltage of the first shutter electrode and the voltage of the second shutter electrode thereby to control the passage of ions of interest through the ion shutter in a drift direction; and wherein the first shutter electrode lies between a reaction region of the IMS cell and the second shutter electrode, and the first shutter voltage provider circuit is configured to match the voltage of the first shutter electrode to a spatially varying profile voltage of the IMS cell prior to opening of the ion shutter. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A control apparatus for an IMS cell comprising:
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a first shutter voltage provider circuit for varying the voltage of a first shutter electrode of an ion shutter; and a second shutter voltage provider circuit for varying the voltage of a second shutter electrode of the ion shutter, wherein; the first shutter voltage provider circuit is configured to match the first shutter electrode voltage to a profile voltage of the IMS cell prior to opening of the ion shutter; the second shutter voltage provider circuit is configured to open the ion shutter by matching the second shutter electrode voltage to the profile voltage; and the first shutter voltage provider circuit is configured to provide a barrier voltage to close the ion shutter by controlling the first shutter voltage to be different from the profile voltage to provide a barrier voltage.
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12. A method of controlling an ion shutter of an IMS cell, the method comprising controlling a barrier voltage between a first shutter electrode and a second shutter electrode to open and close the shutter to allow ions of interest to pass through the shutter in a drift direction by varying the voltage of the first shutter electrode;
- and varying the voltage of the second shutter electrode;
wherein the voltages of the first shutter electrode and the second shutter electrode are varied with respect to a spatially varying profile voltage of the IMS cell;
the method further comprising;providing a voltage of the first shutter electrode which matches the profile voltage and providing a voltage of the second shutter electrode which is different from the profile voltage to close the shutter; providing a voltage to both the shutter electrodes that matches the profile voltage to open the shutter; and providing a voltage of the first shutter electrode that is different from the profile voltage while the voltage of the second shutter electrode matches the profile voltage to close the shutter.
- and varying the voltage of the second shutter electrode;
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13. An IMS cell comprising:
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an ion shutter comprising a first shutter electrode and a second shutter electrode; a first shutter voltage provider circuit configured to vary the voltage of the first shutter electrode; and a second shutter voltage provider circuit configured to vary the voltage of the second shutter electrode, wherein the first shutter voltage provider circuit and the second shutter voltage provider circuit are configured to control a barrier voltage between the first shutter electrode and the second shutter electrode by varying the voltage of the first shutter electrode and the voltage of the second shutter electrode thereby to control the passage of ions of interest through the ion shutter in a drift direction, wherein the first shutter electrode and the second shutter electrode are coplanar. - View Dependent Claims (14)
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Specification