| 摘要 |
When the isolation of a specific ion is performed and a cleavage operation is performed by use of CID, the ion is captured by applying a high frequency high voltage to a ring electrode (31) as before. The ion is captured by applying the high frequency high voltage not to the ring electrode (31) but to end cap electrodes (32, 34) in a cleaning process immediately before the ejection of the ion to a TOFMS (4) in a state in which the target ion is accumulated in an ion trap (3). On this occasion, the frequency is set to be higher and the amplitude is set to be larger than an applied voltage to the ring electrode (31), large pseudopotential is secured, and LMC is maintained. Consequently, the distribution of the space of the cleaned ion is narrowed, the variation of the initial position at the time of the emission of the ion is reduced, and mass resolution is improved. High mass selectivity can be also secured since the ion isolation of a high m/z ion can be performed at a high qz value as before. |
