| 摘要 |
The invention relates to means and methods for the orthogonal introduction of ions into a TOF mass spectrometer, whereby ions from an ion source can be efficiently transferred via a multipole ion guide such that they can be readily analyzed in a TOF analyzer. The invention includes first introducing ions into an ion guide, preferably an RF/DC ion guide, which guides the ions into a multipole ion trap. Both the ion guide and ion trap are preferably orthogonal to the flight direction of the TOF mass spectrometer. By changing the potentials on the electrodes of the multipole ion trap, the ions may be extracted from the trap in the direction of the flight region. Also, in accordance with the invention, the entrance region of the ion guide is held at moderate pressure to cool the ions to thermal energies. These ions are cooled due to collisions with neutral background gas molecules, thus lowering the energy spread of the ions. Preferably, the invention uses different DC and RF electrodes to trap and extract ions. By minimizing the energy spread of the ions, the invention results in improved performance of any TOF mass spectrometer.
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