| 摘要 |
PROBLEM TO BE SOLVED: To stabilize analysis for a long time even if a migration compatible solvent containing non-volatile salt is used by having a vibrator for causing vibration to a needle electrode. SOLUTION: A needle electrode 22 is arranged in the vicinity of a first pore 8. A positive high voltage is applied in positive ion measurement and a negative high voltage of several kilovolt for instance is applied in negative ion measurement from power supply 53 of a high voltage. Thereby, a corona discharge is generated, and primary ions for chemical ionizing is generated. It is desirable that a needle electrode 22 is arranged in a needle electrode cover 26 to retard deposition of salt to the needle electrode 22. A supersonic wave vibrator 28 is attached on the needle electrode 22 or a needle electrode stand 25. When measurement is executed continuously for several hours, non-volatile salt is deposited in the vicinity of a front edge of the needle electrode 22. Then, vibration is applied to the needle electrode 22 with the supersonic wave vibrator 28 to peel sludge, which drops to remove. Since non-volatile salt is deposited on the needle electrode 22 is very fragile, it is possible to remove the salt by dynamics action such as vibration and the impact, etc., to cause acceleration in the needle electrode 22.
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