| 摘要 |
A mass spectrometer is disclosed comprising an ion guide. The ion guide comprises a hollow tubular conductor (1) having a wall. One or more electrodes are provided in the wall of the tubular conductor (1). An exit aperture (3) is provided in the wall of the tubular conductor (1) downstream of the one or more electrodes (2). An AC or RF voltage is applied to the one or more electrodes (2) and a DC potential difference is maintained between the wall of the tubular conductor (1) and the one or more electrodes (2). The combination of a DC voltage gradient and applying an AC or RF voltage to the electrodes (2) is that ions are confined radially to a region which is preferably close to the one or more electrodes (2). Ions are preferably extracted from the ion guide via the exit aperture (3) by maintaining a pressure gradient between the inside of the tubular conductor (1) and the outside of the tubular conductor (1) and/or by maintaining a DC electric field which acts to extract ions through the exit aperture (3). |
