Ion trap mass spectrometer and spectrometry

An ion trap mass spectrometer including a ring electrode, two end cap electrodes disposed opposite to each other so that said ring electrode is disposed between said two end cap electrodes, a radio-frequency power supply for generating a radio-frequency voltage supplied across said ring electrode and said end cap electrodes, an ion source for generating ions, means for capturing said generated ions in an inter-electrode space in which a radio-frequency electric field is generated, means for generating a supplementary AC electric field having a certain specific frequency in said inter-electrode space, and means for detecting ions ejected from said inter-electrode space;

• comprising means for changing an application period of said supplementary AC electric field having said specific frequency applied in order to resonantly exciting ions having a specific mass-to-charge ratio in accordance with ionic species to be dissociated.

An ion trap mass spectrometer including an ion source for generating ions, ion trap electrodes forming an inter-electrode space for capturing the ions, means for generating a supplementary AC electric field having a specific frequency in said inter-electrode space and means for detecting ions ejected from said inter-electrode space;

• comprising operation means for causing a user to input an application period of said supplementary AC electric field having said specific frequency and setting it.

An ion trap mass spectrometry including a step of generating ions by an ion source, a step of capturing the ions in an inter-electrode space formed by ion trap electrodes, a step of generating a supplementary AC electric field having a specific frequency in said inter-electrode space, and a step of detecting ions ejected from said inter-electrode space;

• comprising a step of changing an application period of said supplementary AC electric field having said specific frequency in accordance with ionic species to be dissociated.