Mass spectrometer and mass spectrometric method

A mass spectrometric method comprising the steps of:

• generating sample ions by an ion source;
• allowing said ions to be incident and accumulated into an ion trap having a pair of endcap electrodes and a ring electrode;
• selectively holding precursor ions having a desired mass in said ion trap;
• dissociating said precursor ions, wherein an intermittently-introduced bath gas is introduced through a gas introduction hole arranged in said ring electrode having a center axis arranged so as to pass through the center of said ion trap into said ion trap to dissociate said precursor ions;
• ejecting the dissociated ions from said ion trap;
• and
• detecting the ejected ions.

A mass spectrometric method comprising the steps of:

• generating sample ions by an ion source;
• allowing said ions to be incident and accumulated into an ion trap having a first endcap electrode having an incidence hole into which said ions are incident, a second endcap electrode having an ejection hole from which said ions are ejected, and a ring electrode;
• selectively holding precursor ions having a desired mass in said ion trap;
• dissociating said precursor ions, wherein an intermittently-introduced bath gas is introduced through a gas introduction hole arranged in said ring electrode having a center axis passing through the center of said ion trap to be almost orthogonal to an axis connecting the center axis of said incidence hole and the center axis of said ejection hole into said ion trap to dissociate said precursor ions;
• ejecting the dissociated ions from said ion trap;
• and
• detecting the ejected ions.

A mass spectrometric method comprising the steps of:

• generating sample ions by an ion source;
• allowing said ions to be incident and accumulated into an ion trap having a first endcap electrode having an incidence hole into which said ions are incident, a second endcap electrode having an ejection hole from which said ions are ejected, and a ring electrode;
• selectively holding precursor ions having a desired mass in said ion trap;
• dissociating said precursor ions, wherein an intermittently-introduced bath gas is introduced through a gas introduction hole arranged in said ring electrode having a center axis almost orthogonal to an axis connecting the center axis of said incidence hole and the center axis of said ejection hole so as to reach the center part of said ion trap for dissociating said precursor ions;
• ejecting the dissociated ions from said ion trap;
• and
• detecting the ejected ions.

A mass spectrometric method comprising the steps of:

• generating sample ions by an ion source;
• allowing said ions to be incident and accumulated into an ion trap having a first endcap electrode having an incidence hole into which said ions are incident, a second endcap electrode having an election hole from which said ions are ejected, and a ring electrode;
• selectively holding precursor ions having a desired mass in said ion trap;
• dissociating said precursor ions, wherein an intermittently-introduced bath gas is introduced th a gas introduction hole arranged in said ring electrode having a center axis arranged so as to pass through a region including the center of said ion trap into said ion trap to dissociate said precursor ions;
• ejecting the dissociated ions from said ion trap;
• and
• detecting the ejected ions.

A mass spectrometer method comprising the steps of:

• generating sample ions by an ion source;
• accumulating ions generated by said ion source in an ion trap having a pair of endcap electrodes and a ring electrode;
• isolating precursor ions having a desired mass from the accumulated ions in said ion trap;
• dissociating the precursor ions;
• ejecting the dissociated ions from said ion trap;
• and
• detecting the ejected ions;
• wherein, in the step of accumulating the ions and in the step of isolating the precursor ions, an intermittently-introduced bath gas is introduced through a gas introduction hole arranged in said ring-electrode having a center axis arranged so as to pass through the center of said ion trap into said ion trap;
• and
• wherein, in the step of dissociating of the precursor ions, a laser beam irradiates the isolated precursor ions in the region near the center of the ion trap.