摘要:
A linear ion trap (6,7,8)is disclosed comprising a central quadrupole rod set (6)and a post-filter quadrupole rod set (8). A 180° phase difference is maintained between axially adjacent rod electrodes of the central quadrupole rod set (6) and the post-filter quadrupole (8) so that an axial pseudo-potential barrier is created between the central quadrupole rod set (6) and the post-filter quadrupole (8). A supplementary AC voltage is applied to the rods of the central quadrupole (6) in order to radially excite ions which are desired to be ejected from the ion trap. The ions are ejected from the ion trap (6,7,8) non-adiabatically in an axial direction.
摘要:
A linear ion trap (6, 7, 8)is disclosed comprising a central quadrupole rod set (6)and a post-filter quadrupole rod set (8). A 180° phase difference is maintained between axially adjacent rod electrodes of the central quadrupole rod set (6) and the post-filter quadrupole (8) so that an axial pseudo-potential barrier is created between the central quadrupole rod set (6) and the post-filter quadrupole (8). A supplementary AC voltage is applied to the rods of the central quadrupole (6) in order to radially excite ions which are desired to be ejected from the ion trap. The ions are ejected from the ion trap (6, 7, 8) non-adiabatically in an axial direction.
摘要:
A mass or mass to charge ratio selective ion trap is disclosed which directs ions into a small ejection region. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC or RF voltage acts to confine ions in a second (x) direction. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. The profile of the quadratic DC potential well progressively varies along the second (x) direction.
摘要:
A mass or mass to charge ratio selective ion trap is disclosed having an increased charge storage capacity. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC voltage and/or an RF voltage acts to confine ions in a second (x) direction within the ion trap. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. Ions are excited in the third (z) direction and are caused to be mass or mass to charge ratio selectively ejected in the third (z) direction.
摘要:
A mass spectrometer is disclosed wherein an ion beam attenuator is arranged upstream of an ion trap mass analyser. An ion tunnel ion trap comprising an upstream ion accumulation section and a downstream ion accumulation section is arranged upstream of the ion beam attenuator. Ions are released from the ion tunnel ion trap and the intensity of the ion beam which is transmitted to the ion trap analyser is controlled by the ion beam attenuator. The fill time during which ions are admitted into the ion trap mass analyser remains substantially constant and is substantially independent of the intensity of the ion beam.
摘要:
A mass or mass to charge ratio selective ion trap is disclosed which directs ions into a small ejection region. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC or RF voltage acts to confine ions in a second (x) direction. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. The profile of the quadratic DC potential well progressively varies along the second (x) direction.
摘要:
Ions having a restricted range of mass to charge ratios are transmitted to the acceleration region of a Time of Flight mass analyzer. A control system applies a first extraction pulse to an acceleration electrode in order to accelerate a first group of ions into the time of flight region at a first time T1, wherein ions having the lowest mass to charge ratio in the first group of ions have a time of flight ΔT1min through the time of flight region and ions having the highest mass to charge ratio in the first group of ions have a time of flight ΔT1max through the time of flight region. The control system applies a second extraction pulse to the acceleration electrode at a subsequent second time T2, wherein ΔT1max−ΔT1min≦T2−T1
摘要:
An ion guide is disclosed comprising a plurality of electrodes. A first device is arranged and adapted to apply a RF voltage to at least some of the electrodes in order to form, in use, a pseudo-potential well which acts to confine ions in a first direction within the ion guide. A second device is arranged and adapted to apply a DC voltage to at least some of the electrodes in order to form, in use, a DC potential well which acts to confine ions in a second direction within the ion guide. A third device is arranged and adapted to cause ions having desired or undesired mass to charge ratios to be mass to charge ratio selectively ejected from the ion guide in the second direction.
摘要:
A mass or mass to charge ratio selective ion trap is disclosed having an increased charge storage capacity. A RF voltage acts to confine ions in a first (y) direction within the ion trap. A DC voltage and/or an RF voltage acts to confine ions in a second (x) direction within the ion trap. A quadratic DC potential well acts to confine ions in a third (z) direction within the ion trap. Ions are excited in the third (z) direction and are caused to be mass or mass to charge ratio selectively ejected in the third (z) direction.
摘要:
An ion guide is disclosed comprising a plurality of electrodes. A first device is arranged and adapted to apply a RF voltage to at least some of the electrodes in order to form, in use, a pseudo-potential well which acts to confine ions in a first direction within the ion guide. A second device is arranged and adapted to apply a DC voltage to at least some of the electrodes in order to form, in use, a DC potential well which acts to confine ions in a second direction within the ion guide. A third device is arranged and adapted to cause ions having desired or undesired mass to charge ratios to be mass to charge ratio selectively ejected from the ion guide in the second direction.