Ion-trap mass analyzing apparatus and ion trap mass analyzing method

An ion-trap mass analyzing apparatus having a trap space which is enclosed by electrodes and in which ions are captured and a controller for controlling an AC voltage to be applied to the electrode so as to form a dipole auxiliary electric field and a quadrupole auxiliary electric field, wherein the controller controls the AC voltage so as to form the quadrupole auxiliary electric field after forming the dipole auxiliary electric field.

An ion-trap mass analyzing apparatus having an annular ring electrode and two end cap electrodes facing each other so as to sandwich the ring electrode, wherein RF electric field is formed to trap ions between electrodes by applying RF voltage between the ring and the end-cap electrodes by power supply, and two types of auxiliary AC electric fields are also formed between electrodes;

• one of them is a dipole one which is formed by applying out-of-phase AC voltages between the two end-caps;
• the other is a quadrupole one which is formed by applying in-phase AC voltages between the two end-caps or to the ring electrode;
• being controlled so as to form such quadrupole auxiliary field after forming a dipole auxiliary field alternately.

An ion-trap mass analyzing apparatus having an annular ring electrode and two end cap electrodes facing each other so as to sandwich the ring electrode, wherein at least a high-frequency voltage of a DC voltage and the high-frequency voltage to select an ion species having a mass-to-charge ratio to be detected out of ions stably captured in a quadrupole electric field formed in an inter-electrode space by applying at least high-frequency voltage of a DC voltage and the high-frequency voltage between the ring electrode and the end cap electrodes from a main power supply by generating an auxiliary AC electric field weaker than the quadrupole electric field and thereby, amplifying the trajectories of the ions to be mass selected detected and emitting the ion from the inter-electrode space;

• wherein a dipole auxiliary electric field and a quadrupole auxiliary electric field are temporally alternately applied within a predetermined time to such two types of auxiliary AC electric fields as a dipole auxiliary AC electric field generated by applying AC voltages shifted from each other by half time phase to the two end cap electrodes and a quadrupole auxiliary AC electric field generated by applying AC voltages having the same phase to the two end cap electrodes or applying an auxiliary AC voltage to the ring electrode.

An ion-trap mass analyzing method comprising the steps of applying an AC voltage to an electrode to capture ions in a trap space and forming first and second auxiliary electric fields for supplying energy to the captured ions to increase the amplitude of their oscillation, wherein the first auxiliary electric field has less influence of the amplitude of an ion on the position of it than the second auxiliary electric field and the second electric field is formed after the first electric field is formed.

An ion-trap mass analyzing method comprising the steps of forming an ion-trap space by two end cap electrodes facing each other so as to sandwich an annular ring electrode, forming a dipole auxiliary AC electric field by applying AC voltages shifted from each other by half phase between the two end cap electrodes, controlling the spatial dispersion between ions having the same mass-to-charge ratio, and forming the dipole auxiliary AC electric field and thereafter forming a quadrupole auxiliary AC electric field.

An ion-trap mass analyzing method comprising the steps of applying an AC voltage to an electrode to capture ions in a trap space and forming first and second auxiliary electric fields for increasing the amplitude of the captured ions, wherein the first auxiliary electric field has less influence of the amplitude of an ion on the position of it than the second auxiliary electric field and the second auxiliary electric field is formed after the first auxiliary electric field is formed.

An ion-trap mass analyzing method comprising the steps of applying an AC voltage to an electrode to capture ions in a trap space and forming first and second auxiliary electric fields for increasing the amplitude of the captured ions, wherein the first auxiliary electric field has smaller spatial spread than the second auxiliary electric field and the second auxiliary electric field is formed after the first auxiliary electric field is formed.