Ion entry/exit device

1. An ion entry/exit device for a mass spectrometer and/or ion mobility spectrometer, said device comprising:

at least two arrays of electrodes, wherein each array of electrodes comprises a plurality of electrodes arranged in rows and columns; and

at least one DC voltage supply;

wherein said at least one DC voltage supply is configured to:

in a first mode of operation successively apply DC potentials to successive electrodes of at least one of the electrode arrays in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the device in the first direction;

wherein in said first mode said at least one DC voltage supply applies said DC potentials to the electrodes in a first row and then successively to different rows of electrodes such that said potential barrier moves along the array in the first direction; and/or

wherein in a second mode of operation said at least one DC voltage supply applies DC potentials to the electrodes in a first column and then successively to different columns of electrodes such that a potential barrier moves along the array in a second, different direction.

2. The device of claim 1 , wherein said at least two arrays of electrodes are arranged parallel to each other.

3. A method of introducing and ejecting ions from an ion mobility separation device comprising the ion entry/exit device of claim 1 , said method comprising:

operating the ion entry/exit device in said first mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the ion entry/exit device in the first direction;

wherein in said first mode said DC potentials are applied to the electrodes in a first row and are then successively applied to different rows of electrodes such that said potential barrier moves along the array in the first direction; and/or

operating the ion entry/exit device in said second mode, wherein in said second mode DC potentials are applied to the electrodes in a first column and are then successively applied to different columns of electrodes such that a potential barrier moves along the array in a second, different direction.

4. The method of claim 3 , further comprising supplying RF voltages to said arrays of electrodes so as to confine ions in the direction between the arrays.

5. A mass spectrometer and/or ion mobility spectrometer comprising an ion entry/exit device as claimed in claim 1 .

6. The device of claim 1 , wherein said at least two arrays of electrodes are formed from printed circuit boards.

7. A method of introducing and ejecting ions from an ion mobility separation device, said method comprising:

providing an ion entry/exit region having at least two arrays of electrodes; and

operating the ion entry/exit region in a first mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the region in the first direction;

wherein the method is operated in the first mode and ions are loaded into the region in the first direction, and the method is then operated in a second mode and these ions are ejected from the device in a second, different direction.

8. A method of introducing and ejecting ions from an ion mobility separation device, said method comprising:

providing an ion entry/exit region having at least two arrays of electrodes;

temporally separating ions according to a physicochemical property prior to their entry into the ion entry/exit region; then

receiving the ions in the ion entry/exit region;

operating the ion entry/exit region in a first mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the region in the first direction so that the temporally separated ions are ejected from the region in the first direction; and

temporarily operating the ion entry/exit region in a second mode so as to selectively eject ions having a selected value, or range of values, of said physicochemical property from the region.

9. A method of introducing and ejecting ions from an ion mobility separation device, said method comprising:

providing an ion entry/exit region having at least two arrays of electrodes;

operating the ion entry/exit region in a first mode, wherein DC potentials are successively applied to successive electrodes of at least one of the electrode arrays in a first direction such that a potential barrier moves along the at least one array in the first direction and drives ions into and/or out of the region in the first direction;

ejecting said ions from the ion entry/exit region into an ion guide;

wherein the ion guide comprises electrodes and the method comprises applying DC voltages to the electrodes of the ion guide so as to drive ions along the longitudinal axis of the ion guide; and

wherein either a static DC potential gradient is applied along the axial length of the ion guide so as to drive ions along said longitudinal axis; or

wherein one or more DC potentials is applied to successive electrodes along the axial length of the ion guide such that a DC potential barrier travels along the length of the ion guide and drives ions along the ion guide.

10. The method of claim 9 , wherein ions are driven out of the ion entry/exit region, into the ion guide and are then reintroduced back into the ion entry/exit region.

11. The method of claim 10 , wherein the potential barrier in the ion entry/exit region urges the reintroduced ions out of the ion entry/exit region again so that the ions and pass through the ion guide again.

12. The method of claim 10 , wherein the ions pass through the ion guide≥x times, wherein x is 2, 3, 4, 5, 6, 7, 8, 9, 10, 15 or 20.

13. The method of claim 9 , wherein the ion entry/exit region and/or ion guide forms an ion mobility separator in which the ions separate along the longitudinal axis according to their ion mobilities.

14. The method of claim 13 , wherein the ions separate according to their ion mobilities as they pass along the ion guide, and wherein the ion entry/exit region is then switched so as to eject at least some of the separated ions out of the device into a further ion guide, ion trap, or ion processing device.

15. The method of claim 14 , wherein the ion entry/exit region is temporarily switched such that only ions of a first ion mobility, or first range of ion mobilities, that have passed along the ion guide are ejected out of the ion entry/exit region, whilst other ions having a second ion mobility, or second range of ion mobilities, continue on to pass through the ion guide again.

16. The method of claim 14 , wherein the selectively ejected ions are stored, mass analysed, fragmented to form fragment ions, or reacted with ions or molecules to form product ions within said further ion guide, ion trap, or ion processing device.

17. The method of claim 14 , comprising reintroducing the selectively ejected ions, fragment ions or product ions into the ion entry/exit region such that the reintroduced ions pass into the ion guide again.