65 results about "Quadrupole ion trap" patented technology

A quadrupole ion trap mass analyzer in which the trapping volume is defined by spaced linear rods in which linear elements located between the spaced linear rods produce image currents produced by motion of ions in the trapping volume.

A mass spectrometer is disclosed wherein a relatively energetic pulse of ions having a relatively narrow spread of mass to charge ratios are ejected from a quadrupole ion trap and received in an ion trap upstream of a Time of Flight mass analyser. The ions are collisionally cooled within the ion trap and are pulsed out of the ion trap and into an extraction region of the Time of Flight mass analyser without substantially exciting the ions. This enables improved operation with the Time of Flight mass analyser. According to another embodiment, parent ions are fragmented and the resulting fragment ions are stored in two ion traps having different low mass cut-offs. The trapping system enables MS/MS experiments to be performed with a very high duty cycle.

A digital drive apparatus (FIG. 3) for quadrupole device such as a quadrupole ion trap has a digital signal generator (11, 13, 14; 24, 25, 26) and a switching arrangement (16, 17) which alternately switches between high and low voltage levels (V₁, V₂) to generate a rectangular wave drive voltage. A dipole excitation voltage is also supplied to the quadrupole device to excite resonant oscillatory motion of ions.

The invention relates to the fragmentation of ions in ion traps filled with collision gas by exciting their axial oscillations in a dipole-shaped excitation field with a frequency mixture which covers the frequency of ion oscillations. The invention consists of ramping up the voltages of the frequency mixture for the dipolar excitation field, as a result of which, surprisingly, approximately the same fragmentation results are obtained for ions of different structures in the same fragmentation times as at a structurally specific optimal voltage applied at a constant level.

The invention relates to a method and instrument for the fragmentation of large molecular analyte ions, preferably biopolymer ions, by reactions between multiply charged positive analyte ions and negative reactant ions in RF quadrupole ion traps. Some of these reactions involve electron transfer reactions with subsequent dissociation of the biopolymer analyte ions, and some involve the loss of a proton, leading to stable product ions. The invention can use any type of ion traps, particularly three-dimensional RF quadrupole ion traps, for the reactions between positive and negative ions. The fragmentation yield can be increased because ions that remain stable as radical cations after transfer of an electron are further fragmented by collisionally induced fragmentation, forming fragment ions that are typical of electron transfer, and not those typical of collisionally induced fragmentation. The invention preferentially introduces positive ions and negative ions into the ion trap sequentially through the same aperture.

A quadrupole ion trap device has a field adjusting electrode located outside the trapping region adjacent the aperture in the entrance end cap electrode, and optionally adjacent the aperture in the exit end cap electrode. The field adjusting electrode(s) controls field distortion in the vicinity of the apertures. By appropriately setting the voltages on the field adjusting electrodes the efficiency and resolution of operational processes such as ion introduction, precursor ion isolation and mass scanning can be improved.

An ion trap is provided in which higher multipole field fractions can be switched on and off and, in addition, can be electrically tuned. Specifically, the electrodes of an ideally shaped ion trap are divided into rotationally symmetrical component electrodes positioned facing the interior of the ion trap on a hyperboloidal surface with rotationally symmetry.

There is provided a quadruple ion trap (22) of the type including a ring electrode (24) and first and second end cap electrodes (26, 28), which define a trapping volume. The end cap electrodes (26, 28) include central apertures (30) for the injection of ions or electrons into the trapping volume and for the ejection of stored ions during the analysis of a sample. Field faults in the RF trapping field are compensated by addition of a concentric recess or depression in the surface of at least one end cap (26, 28) around the aperture (30). There is also provided an ion trap mass spectrometer employing the ion trap.

A mass spectrometric device of the present invention includes a quadrupole filter (12) located upstream of a quadrupole ion trap (13) and configured to transmit ions in a predetermined filter range, and determines the filter range of the quadrupole filter (12) such that accumulation time for the ions in the quadrupole ion trap (13) is maximized. The accumulation time for the ions is determined based on mass spectrometry data information. With this configuration, the present invention produces advantageous effects of improving analysis throughput and an S/N ratio in an analysis of a minor sample component mixed in various accompanying components by using the mass spectrometric device using the quadrupole ion trap.

A system and method are disclosed for effectively compensating for non-linear field components created by a field distortion feature in a quadrupolar ion trap, compensation provided by a geometric surface shaping which reduces the non-linear field components and creates a minimal centerline radio-frequency potential in the ion trap. The ion trap includes a centerline that passes longitudinally through a trapping volume inside of the ion trap, a pair of Y electrodes with inner Y electrode surfaces that are approximately parallel to the centerline, and a pair of X electrodes with inner X electrode surfaces that are approximately parallel to the centerline. The X electrodes have one or more ejection slots through which trapped ions are ejected from said ion trap. The inner Y electrode surfaces each have a Y radius of curvature, and the inner X electrode surfaces each have an X radius of curvature. The X radius of curvature is selected to be smaller than the Y radius of curvature. A balanced centerline potential is provided at the centerline of the ion trap.

An aperture design for a linear ion trap is provided in which the aperture is optimized to minimize possible axial field inhomogeneities whilst preserving the structural integrity of the quadrupole rods. In general, the invention provides a linear ion trap for trapping and subsequently ejecting ions. The linear ion trap comprises a plurality of rods which define an interior trapping volume which has an axis extending longitudinally. One or more of the rods includes an aperture which extends both radially through the rod and longitudinally along the rod. The aperture being configured such that the ions can pass from the interior trapping volume through the aperture to a region outside the interior trapping volume. At least one recess is disposed adjacent the aperture, extending longitudinally along the rod and facing the interior trapping volume, the recess not extending radially through the rod.

The invention provides a small two-stage vacuum rectangular ion trap mass spectrometer and a detection method thereof. The mass spectrometer comprises two stages of vacuum cavities. The first-stage vacuum cavity is internally provided with an atmospheric pressure interface sampling cone, a quadrupole rod and an ion gate electrode which form a quadrupole ion trap. The second-stage vacuum cavity is internally provided with a rectangular ion trap, an ion detector and a capillary tube. An ion optical element is arranged between the two stages of vacuum cavities. The detection method includes the steps that the quadrupole ion trap in the first-stage cavity is controlled to be in an ion trap storage mode and an ion trap synchronous analysis mode so that sensitivity of mass spectra can be improved, the quantitation limit is reduced, analysis flux is increased, influences of the space charge effect are reduced, and the resolution is increased. The quadrupole rod does not need high resolution and is low in processing precision requirement. Besides, the rectangular trap is easy to process and assemble, so that miniaturization is facilitated. Meanwhile, the detection method can guarantee good analysis performance and has wide application prospects in the field of on-site analysis and detection.

A RF only quadrupole rod set mass filter or mass analyser and a linear quadrupole ion trap with axial ejection are disclosed comprising a first pair of rod electrodes, a second pair of rod electrodes and an energy filter. The first pair of rod electrodes is longer than the second pair of rod electrodes. Ions having desired mass to charge ratios experience fringing fields at an exit region which results in the ions possessing sufficient axial kinetic energy to be transmitted by the energy filter. Other ions possess insufficient axial kinetic energy to be transmitted by the energy filter and are attenuated.