MASS SPECTROGRAPH APPARATUS AND METHOD OF DRIVING ION GUIDE

摘要

In eight electrodes arranged at an interval of a rotational angle of 45° around an ion optical axis, two neighboring electrodes are electrically connected together as one group, and electrodes in alternate groups are also electrically connected together. A voltage VDC+v cos ωt is applied to electrodes in alternate groups around the optical axis, and a voltage VDC−v cos ωt is applied to the other electrodes. Then, while an ion guide has the same electrode structure as that of an octupole-type ion guide, a radio-frequency electric field mainly having a quadrupole field component is formed, and the ion guide can be used as a quadrupole-type ion guide. Accordingly, only by changing the wiring for applying a voltage by using the electrodes having the same structure, ion guides of, for example, a quadrupole type and an octupole type, having different properties such as ion receiving properties and ion passing properties can be achieved.

主权项

1. A mass spectrometer comprising an ion guide in which 2n (where n is an integer equal to or larger than 3) rod-like or plate-like electrodes extending along an ion optical axis are arranged so as to surround the ion optical axis, the mass spectrometer further comprising:
a) voltage generating means for generating a first radio-frequency voltage and a second radio-frequency voltage having a same amplitude as and an inverted phase from the first radio-frequency voltage, as voltages for forming a radio-frequency electric field in a space surrounded by the respective electrodes of the ion guide; and b) electrical connecting means for electrically connecting the voltage generating means and the respective electrodes of the ion guide such that the first radio-frequency voltage is applied to m (where m is an integer equal to or larger than 2 and equal to or less than 2n−1) electrodes adjacent to each other around the ion optical axis among the 2n electrodes constituting the ion guide, and the second radio-frequency voltage is applied to at least one of the other 2n−m electrodes.