Ion trap for enhanced time-of-flight ion utilization

Abstract

In some examples, the ion trap can include an ion trap controller to apply a trapping potential and a scan voltage waveform to the at least one electrode to sequentially release ions of a higher mass-to-charge ratio (m / z) before ions of a lower mass-to-charge ratio. The ion trap can also have a linear configuration. Ions ejected from the ion trap can be perpendicular to an axis of the ion trap.

Description

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 548,604, filed February 1, 2024, entitled “ION TRAP FOR ENHANCED TIME-OF-FLIGHT ION UTILIZATION”, which is incorporated herein by reference in its entirety. Background Technology

[0002] Ion traps are used to capture charged particles (called ions). Ion traps utilize electric and / or magnetic fields to capture ions. Ion traps have applications in various fields, including physics and chemistry. In one example, an ion trap can be used for mass spectrometry analysis.

[0003] Brief description of the attached figures Features of this disclosure are illustrated by way of example rather than limitation in the following figures, wherein the same reference numerals denote the same elements: Figure 1 An example of an ion trap for enhancing time-of-flight ion utilization is shown according to this disclosure; Figure 2A An example of the undisturbed effective potential in the absence of a scanning waveform, according to this disclosure, is shown. Figure 2B An example of a combined potential in the presence of a scanning waveform is shown according to this disclosure; Figure 3 An example according to this disclosure is shown: in a quadrupole trap with a slit rod, the combined potentials at different time points during the scan for three different m / z ratios of ions are shown. Figure 4A The structure of a device (e.g., an ion trap) as a three-dimensional ion trap is shown. Figures 4B to 4F The diagram illustrates the construction of a device (e.g., an ion trap) as a linear ion trap, wherein ions are positioned between two adjacent rods (e.g., Figure 4D and Figure 4F ) or through a slit in a multipole (e.g. Figure 4B , Figure 4C and Figure 4E The ejection is based on one example of this disclosure; Figure 5 An example of a quadrupole linear ion trap with a slit ejection rod in positive ion mode is shown according to this disclosure. Figure 6A The emission time of the ions and the time it takes for them to reach the intermediate pulser after passing through the ion optical transport device are shown. Figure 6B The kinetic energy of the ions at the intermediate pulser position is shown, according to one example of this disclosure; Figure 7 An example of ion positive alternation according to this disclosure is shown to enter Figure 1 The ion trap, the ion trap, and the ion being accelerated into the time-of-flight (TOF) mass analyzer; Figure 8 An example is shown according to this disclosure, for Figure 1 The number of radio frequency cycles required for the ion trap to achieve an acceptable ratio of the standard deviation to the average kinetic energy of ions after passing through the ion optical transmission device. Figure 9 The illustration shows a separate electrode according to an example of this disclosure, including an electrode for applying a scanning waveform and an electrode for applying a radio frequency waveform; and Figure 10 An example according to this disclosure is shown. Figure 9 Further details on the operation of the separation electrode. Detailed Implementation

[0004] For simplicity and illustrative purposes, this disclosure is described primarily by way of examples. In the following description, numerous specific details are set forth in order to provide a thorough understanding of this disclosure. However, it will be apparent that this disclosure can be practiced without being limited to these specific details. In other instances, some methods and structures have not been described in detail so as not to unnecessarily obscure this disclosure.

[0005] Throughout this disclosure, the terms “an” and “a kind”, and in cases where no quantifier is used, are intended to indicate at least one specific element. As used herein, the term “includes” means including but not limited to, and the term “including” means including but not limited to. The term “based on” means at least partially based on.

[0006] This paper discloses an ion trap for enhancing time-of-flight ion utilization and a method for enhancing time-of-flight ion utilization. The ion trap and method disclosed herein provide a rapid scanning ion trap device to improve ion utilization in time-of-flight mass spectrometers.

[0007] Ion traps can include two general types (e.g., geometries) that utilize alternating radio frequency electric fields to generate harmonic effective potentials (also known as pseudopotentials), which can be used to generate mass-to-charge ratio specific spectra. An example of a geometry can include three-dimensional (3D) ion traps and linear ion traps. Other geometries utilizing radio frequency electric fields (e.g., hexapoles, octapoles, and non-hyperbolic quadrupoles) can be used as ion traps (e.g., with some basic mass analysis capabilities) because these geometries do not generate harmonic potentials.

[0008] The aforementioned 3D ion trap may include a ring electrode and two end cap electrodes, the shape of which allows a potential difference to be applied between the end cap electrodes and the ring electrode. 0 = + f( When this occurs, a harmonic effective potential is generated around the center of the device. For a potential difference... 0 = + f( ), Indicates a constant direct current (DC) voltage value. The amplitude of the radio frequency (RF) waveform is represented by f, where f represents a 2π periodic function (e.g., cosine), and ω represents the angular frequency of the RF waveform. 3D ion traps can include two main operating modes: mass-to-charge ratio selective instability mode and mass-to-charge ratio selective resonant excitation mode.

[0009] Regarding the mass-to-charge ratio selective instability mode, ion trajectories in this device can be calculated and classified into two categories: stable trajectories and unstable trajectories. Whether a trajectory is stable (i.e., whether the ion is confined within the physical boundaries of the device) depends on its mass-to-charge ratio, U, V, ω, and the inscribed radius r0 of the device. Stable and unstable trajectories can be visualized as region maps using reduced variables a (depending on U, m / z, r0, and ω) and q (depending on V, m / z, r0, and ω). A set of variables can be initially selected such that ions of interest within a specific m / z range acquire stable trajectories, and then one or more of these variables are scanned over time to sequentially transform certain m / z ranges from unstable trajectories to stable trajectories. Furthermore, it is possible to select which dimension of ion motion becomes unstable, and ions with specific m / z values ​​can be released from the trap through openings in either or both end cap electrodes. Ions leaving the trap can be detected or guided to another device (e.g., an ion guide within a mass spectrometer).

[0010] Regarding mass-to-charge ratio selective resonant excitation modes, when all ions of interest are in the stable region (i.e., trapped), an additional RF signal can be applied to one or more electrodes. This technique utilizes the fact that the effective potential well depth depends on the mass-to-charge ratio, thus ions with different mass-to-charge ratios have different resonant frequencies within the well. By applying an additional RF signal (e.g., a frequency lower than the main trapping RF frequency) matched to the resonant frequency of a specific mass-to-charge ratio (i.e., the resonant excitation waveform), the originally stable ion trajectories can be manipulated, resulting in an increase in ion spatial amplitude until they are eventually ejected through openings in the endcap electrodes.

[0011] The aforementioned linear ion trap (LIT) may include four hyperbolic quadrupoles, when a potential difference is applied between each adjacent pole. 0 = + f( When the ion trap is activated, a 2D harmonic effective potential is generated along the linear ion trap axis. The constraint of the remaining dimensions (e.g., along the axial direction) may need to be achieved through end cap electrodes or quadrupole segments, or the device can be used as a flow device, referred to as a quadrupole mass filter.

[0012] Similar to 3D ion traps, LITs can use either mass-to-charge ratio-dependent unstable or resonant emission modes to eject, transfer, or detect ions. In resonant emission mode, ions with a specific mass-to-charge ratio can be ejected through slits in one or more electrodes or between electrodes. When used as a flow-through mass filter, no end caps or quadrupole segments are required for trapping; ions with stable trajectories can pass through the device, while ions with unstable mass-to-charge ratios cannot, as they either collide with the electrodes or are ejected between the rods.

[0013] Unstable modes can have drawbacks: ions exiting the trap exhibit a broad kinetic energy distribution, depending specifically on the radio frequency phase at which they are emitted (which in turn depends on the initial conditions of the captured ions, which are practically uncontrollable). This kinetic energy distribution may be broader than the acceptable kinetic energy distribution for pulsers in time-of-flight mass spectrometers. Furthermore, during mass scans, low mass-to-charge ratio ions may be emitted first when scanned in a manner that allows other (higher) mass-to-charge ratio ions to remain on stable trajectories (and thus be preserved during the scan).

[0014] Mass-to-charge ratio selective resonant excitation modes can also have drawbacks: while these modes allow for arbitrary emission of mass-to-charge ratios, the resonant frequencies are typically limited by the maximum effective potential depth achievable by stable ion trajectories, ranging up to 200 kHz. For example, with the ion traps disclosed herein for enhancing time-of-flight ion utilization, the time difference between the lowest mass-to-charge ratio ions (e.g., m / z = 100) and the highest mass-to-charge ratio ions (e.g., m / z = 3000) is approximately 100 microseconds. Therefore, up to 20 excitation waveform periods can be “crammed” into the available scan time, necessitating the use of resonant excitation waveforms with higher amplitudes. Higher amplitudes of approximately 1 V or higher can result in a wider emission ion kinetic energy distribution, which is unacceptable for orthogonal accelerated time-of-flight mass spectrometers.

[0015] For the ion traps disclosed herein for enhancing time-of-flight ion utilization, in a typical orthogonal accelerated time-of-flight mass spectrometer, ions can be pulsed and accelerated along the orthogonal direction of the incident ion beam. Their arrival time is detected at the detector, typically after one or more ion mirrors, to extend flight time and distance for better performance (e.g., resolution). The maximum pulse frequency may depend on the highest mass-to-charge ratio that should be detectable in the mass spectrum. Depending on the final time-of-flight energy of the ions (e.g., 5 keV) and path length, a new pulse can be emitted after the slowest (i.e., highest mass-to-charge ratio) ion arrives at the detector.

[0016] Axial kinetic energy and time-of-flight kinetic energy orthogonal to the incident ion beam axis may form an angle such that an ion strikes the detector at a given location. Axial kinetic energy is invariant under the first-degree approximation and is therefore preserved. A technical challenge associated with pulsed continuous-current ion beams is that only a mass-dependent portion of the beam can be pulsed, while ions that do not encounter a pulse are not accelerated and therefore cannot be detected. This is called duty cycle (DC), a measure of ion utilization. In any orthogonal accelerated-time-of-flight mass spectrometer that pulses from a continuous ion beam, the maximum duty cycle (e.g., for the highest mass-to-charge ratio to be detected) is equal to the ratio of the detector width (or accelerator width, whichever is smaller) to the distance between the accelerator and detector. The duty cycle for the highest mass-to-charge ratio (DC) Examples of values ​​for this parameter are found in single-reflection time-of-flight (TOF) mass spectrometers, ranging from 10% to <50%, while in multiple-reflection time-of-flight mass spectrometers, the value is relatively smaller if no ion trapping scheme is used before the pulse. Lower mass-to-charge ratios result in lower duty cycles as follows: In this regard, the ion trap disclosed herein for enhancing time-of-flight ion utilization increases the duty cycle of all mass-to-charge ratios of interest to approximately 100%, thereby significantly improving instrument performance (e.g., sensitivity).

[0017] According to the examples disclosed herein, ion traps for enhancing time-of-flight ion utilization avoid ion loss caused by orthogonal extraction of continuous ion beams in time-of-flight mass spectrometers.

[0018] According to the examples disclosed herein, ion traps for enhancing time-of-flight ion utilization improve ion beam characteristics, such as the primary radial energy distribution (e.g., potentially improving resolution) and the axial energy distribution (e.g., avoiding ion loss due to ions not hitting the detector).

[0019] According to the examples disclosed herein, ion traps for enhancing time-of-flight ion utilization allow for efficient scanning of ions with different mass-to-charge ratios.

[0020] According to the examples disclosed herein, an ion trap may include at least one rod and an ion trap controller for applying a trapping potential and a scanning voltage waveform to at least one electrode operatively connected to said at least one rod to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions. The ion trap may also include a linear configuration. Ions ejected from the ion trap may be perpendicular to the axis of the ion trap. The ion trap controller may be executed by at least one hardware processor. Alternatively, the ion trap controller may be a field-programmable gate array (FPGA).

[0021] According to the examples disclosed herein, ions can include a mass-to-charge ratio range of 100 to 3000.

[0022] According to the examples disclosed herein, a linear configuration may include a linear quadrupole configuration. The at least one rod may include a slit rod. The at least one rod may include four rods, each including the slit rod having an RF trapping potential applied to these four rods.

[0023] Based on the examples disclosed herein, the linear configuration may include a linear quadrupole configuration. The at least one rod may include a slit rod. The at least one rod may include four rods, including a slit rod having an RF trapping potential applied to two of the rods.

[0024] Based on the examples disclosed herein, a linear configuration may include a linear quadrupole configuration. The at least one rod may include two rods for ion ejection between the two rods.

[0025] Based on the examples disclosed herein, a linear configuration may include a linear six-pole configuration. The at least one rod may include an exit rod with a slit.

[0026] Based on the examples disclosed herein, a linear configuration may include a linear hexapolar configuration. The at least one bar may include two bars for ion ejection between the two bars.

[0027] According to the examples disclosed herein, the at least one pole may include a pole with a slit, to which a scanning voltage waveform is applied. Furthermore, the at least one pole may include a first set of poles including the pole with the slit, to which a first radio frequency (RF) waveform is applied, and the at least one pole may include a second set of poles to which a second RF waveform is applied.

[0028] According to the examples disclosed herein, the slit rod to which a first RF waveform is applied can represent an inner slit rod, and the slit rod to which a scanning voltage waveform is applied can be arranged behind the inner slit rod relative to the center of the ion trap to pull ions out from the center of the ion trap.

[0029] According to the examples disclosed herein, an ion trap may include a three-dimensional quadrupole configuration comprising two end cap electrodes. One end cap electrode may include an inlet opening, and the other end cap electrode may include an outlet opening. The three-dimensional quadrupole configuration may also include a central ring electrode. The ion trap may also include an ion trap controller for applying a trapping potential and a scan voltage waveform to at least one of the end cap electrodes and the central ring electrode to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions.

[0030] According to the examples disclosed herein, a component may include an ion trap comprising a three-dimensional quadrupole configuration or a linear configuration to sequentially release higher mass-to-charge ratio ions prior to lower mass-to-charge ratio (m / z) ions. The component may also include an ion optical transport device for transporting the sequentially released ions to an ion accelerator. Furthermore, the ion accelerator may accelerate ions from the ion optical transport device.

[0031] Based on the examples disclosed herein, for the components described above, the ion accelerator may be part of a time-of-flight (TOF) mass analyzer (not shown).

[0032] According to the examples disclosed herein, for the aforementioned components, the ion accelerator can accelerate ions from the ion optical transport device in a direction perpendicular to the ion beam entering the ion trap and also perpendicular to the ion beam direction in the ion optical transport device. In this respect, this double bend of the ion beam reduces detector noise while achieving an ultimate vacuum in the TOF mass analyzer.

[0033] According to the examples disclosed herein, an ion trap may include a gap between a slit rod and the starting end of an ion optical transmission device. This ion trap can avoid abrupt transitions from the RF rod field to the ion optical transmission field, thereby eliminating most of the kinetic energy broadening dependent on the RF phase. In this regard, the gap between the slit rod and the starting end of the ion optical transmission device may be similar to R0 (e.g., the inscribed radius) disclosed herein, but may also depend on factors such as the geometry of the rod and lens, ion velocity, and RF frequency.

[0034] Based on the examples disclosed herein, another criterion that can be applied to the ion trap disclosed herein is the minimum number of RF cycles that ions undergo as they transition from the slit exit to the inlet of the ion optical transport device (or, if there is no ion optical transport device, the inlet of the ion accelerator). In this regard, too small a gap (e.g., between the slit rod and the starting end of the ion optical transport device) may cause the kinetic energy of the ions to depend on the RF phase during the transition between devices. Too large a gap may cause excessive radial beam divergence.

[0035] According to the examples disclosed herein, for the ion trap disclosed herein, the ion optical transport device, or the ion accelerator without the ion optical transport device, can be spaced at a distance from the slit such that the electric field RF amplitude gradually decays from its maximum value to a sufficiently low value, such that ions crossing this distance experience a sufficiently high number of RF cycles (e.g., 20), and such that the kinetic energy broadening of the ions reaching the accelerator is sufficiently low (e.g., the ratio of the average kinetic energy to the standard deviation, such that the standard deviation is less than 3% of the average).

[0036] For the ion traps disclosed herein, the controller of the ion trap (e.g., an ion trap controller) can be any combination of hardware and programming to implement the functionality of the various elements of the ion traps and / or components disclosed herein. In some examples described herein, the combination of hardware and programming can be implemented in a variety of different ways. For example, the programming for these elements can be processor-executable instructions stored on a non-transitory machine-readable storage medium, and the hardware for these elements can include processing resources that execute these instructions. In these examples, the computing device implementing these elements can include a machine-readable storage medium storing the instructions and processing resources that execute the instructions, or the machine-readable storage medium can be stored separately and accessible by the computing device and processing resources. In some examples, some elements can be implemented in a circuit.

[0037] Figure 1 An example of an ion trap for enhancing time-of-flight ion utilization, hereinafter referred to as "ion trap 100", is shown according to this disclosure.

[0038] refer to Figure 1 The ion trap 100 can store ions with a wide mass-to-charge ratio (m / z) range for a period of time, and then release these ions sequentially, for example, releasing high-mass-to-charge ratio ions first, followed by low-mass-to-charge ratio ions. Furthermore, all ions can have a narrow kinetic energy distribution, ideally with the same average value for all mass-to-charge ratios. The delay between specific mass-to-charge ratios should ensure that all ions within the range of mass-to-charge ratios of interest arrive simultaneously at a spatial point downstream of the ion trap 100 after passing through the ion optical transport device 102 (e.g., an ion optical guide), so as to be pulsed, for example, by the ion accelerator 104 (e.g., a pulser) in an orthogonal accelerated time-of-flight mass spectrometer.

[0039] Ion trap 100 may include a linear quadrupole geometry in which ions are ejected orthogonally relative to the ion trap axis. Ejection can be achieved using slit rods or between two rods. For ion trap 100, the operating mode of ion trap 100 may allow for sufficiently fast scan rates and sufficiently narrow ejected ion energies to serve as an ion storage device placed in front of an ion accelerator 104 (e.g., a pulser) used in a time-of-flight mass spectrometer. Other geometries (e.g., three-dimensional ion traps) may also be implemented.

[0040] To orthogonally accelerate ions from a continuous ion source within the range of mass-to-charge ratios of interest (e.g., m / z = 100 to 3000), it may be necessary to capture and release ions sequentially so that all ions arrive at the accelerator 104 (e.g., a pulser) simultaneously after passing through the ion optical transport device 102. The ion optical device can be direct current (DC), so the ions nominally have the same kinetic energy. Ions with higher mass-to-charge ratios move slower than those with lower mass-to-charge ratios. Releasing ions with higher mass-to-charge ratios earlier than those with lower mass-to-charge ratios in an explicit manner ensures that the ions arrive simultaneously near the center of the desired acceleration region. In one example, the ion optical transport device 102 can be on the order of 10 to 100 millimeters, with axial ion energies in the range of 3 to 30 eV. Therefore, the required delay time between ions with m / z = 3000 and ions with m / z = 100 may be on the order of 100 microseconds.

[0041] Regarding mass spectrometry analysis, if the ion trap 100 is used as a mass selection device, the scan rate is preferably on the order of 2 E7 Thompsons per second. Alternatively, if the accelerator region is large enough (e.g., within practical constraints), a high mass resolution is not required; a mass resolution of approximately 10 (m / Δm) is sufficient.

[0042] Ion trap 100 may include an ion trap controller 106 (executed by at least one hardware processor) for applying a trapping potential and a scan voltage waveform to at least one electrode operatively connected to the at least one rod to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions. In this respect, ion trap 100 can provide a relatively high scan rate. Furthermore, for ion trap 100, the scan voltage may be monotonically increasing / decreasing rather than periodic.

[0043] Regarding the ion trap controller 106, the ion trap 100 can utilize a combination of a trapping potential and a scanning voltage waveform applied to one or more electrodes. The trapping potential (also known as the effective potential) (or pseudopotential) can be generated by an oscillating electric field, where the scanning waveform ( ) is a monotonic function used to deform the effective potential. Initially, the scan waveform is zero, and ions are allowed to be at the center of ion trap 100 ( = 0) accumulates. As the scanning waveform ( As the value of ) increases, the local minimum of the combined potential (e.g., the effective potential and the potential generated by the scanning waveform) is directed toward the outlet of the ion trap 100. = 0), and the ions are eventually ejected from the ion trap 100. Since the depth of the effective potential generated by the oscillating electric field depends on the mass-to-charge ratio, and ions with higher mass-to-charge ratios have lower effective potential depths, ions with higher mass-to-charge ratios are released before ions with lower mass-to-charge ratios. Therefore, the combined potential changes from a shape with local minima to a shape without local minima at a specific (e.g., m / z dependent) scanning voltage.

[0044] Figure 2A This illustrates an example of the undisturbed effective potential in the absence of a scanning waveform according to this disclosure. Figure 2B The combined potential in the presence of a scanning waveform is shown as an example according to this disclosure.

[0045] refer to Figure 2A When there is no scanning waveform (U( The undisturbed effective potential of (=0) = 0) is shown at 200. Furthermore, refer to... Figure 2B When a scanning waveform exists (U( The combined potential of >0) >0) is shown at 202. The potential at m / z = 3000 lacks a local minimum, at which ions with this mass-to-charge ratio will be ejected from the trap, while ions at m / z = 300 remain confined to the vicinity of the local potential minimum.

[0046] Figure 3 The present disclosure illustrates, according to an example, the combined potentials at different time points during a scan for three ions with different mass-to-charge ratios in a quadrupole trap with a slit rod.

[0047] refer to Figure 3 During a typical scan, the combined potential of ions with three different mass-to-charge ratios at different time points in a quadrupole trap with a slit rod is shown at 300. Figure 3 , U indicates Figure 4B Scan voltage in 3( ) 1( The rhombus at 302 indicates the ion position near the local minimum of the combinatorial potential. High mass-to-charge ratio ions are present at the start of the scan. (V=0) are trapped in shallower effective potentials, and their potentials are deformed early with moderate voltages. As the m / z value decreases, the effective potential increases, requiring higher values. V significantly deforms the potential, causing the local minimum to move toward the exit rod with the slit.

[0048] Different scanning parameters or combinations thereof can be used to selectively deform the effective potential with quality. For example, a constant bias voltage can be used to scan the RF frequency, scan the RF amplitude, use a non-sinusoidal waveform (e.g., a square wave), a combination of duty cycles, and / or amplitude and frequency.

[0049] Figure 4A The structure of a device (e.g., ion trap 100) as a three-dimensional ion trap is shown. Figures 4B to 4F The diagram illustrates the construction of a device (e.g., ion trap 100) as a linear ion trap, wherein ions are positioned between two adjacent rods (e.g., Figure 4D and Figure 4F ) or through a slit in a multipole (e.g. Figure 4B , Figure 4C and Figure 4E The emission is based on one example of this disclosure.

[0050] refer to Figure 4A Ion trap 100 can be constructed as a three-dimensional ion trap as shown in 400, or as a linear ion trap (e.g., at 402, 404, 406, 408, and 410), wherein ions are located between two adjacent rods (e.g., Figure 4D and Figure 4F ) or through a slit in a multipole (e.g. Figure 4B , Figure 4C and Figure 4E ) Ejected. Due to the lower requirement for mass resolution, even higher-order multipole electrodes (e.g., in the case of linear ion traps), such as hexapole electrodes (e.g. Figure 4E and Figure 4F (or octagonal rod)

[0051] Refer again Figures 4A-4F , Figure 4A An ion trap 100 is shown as a three-dimensional quadrupole ion trap, which includes an inlet (e.g., Figure 4A (left side) and exit opening (e.g.) Figure 4A The two end cap electrodes 412 and 414 on the right side, and the central ring electrode 416. Figure 4B An ion trap 100 is shown as a linear quadrupole ion trap, having a slit rod 418, and applying a radio frequency trapping potential to all four rods (e.g., 418, 420, 422, and 424). Figure 4C An ion trap 100 is shown as a linear quadrupole ion trap, having a rod 426 with slits, and an RF trapping potential with an amplitude twice that of the two rods (e.g., 428 and 430) is applied to the two rods (e.g., generating a potential similar to the one shown). Figure 4B Example of the same RF capture potential depth. Figure 4D An ion trap 100 is shown as a linear quadrupole ion trap, which ejects ions between two rods (e.g., at 432). Figure 4E An ion trap 100 is shown as a linear hexapole ion trap, which has an exit rod 434 with a slit. Figure 4F An ion trap 100 is shown as a linear hexapole ion trap, which ejects ions between two rods (e.g., at 436). For Figures 4A-4F , 0 represents a constant bias voltage shared by all electrodes. () represents a 2π periodic function, such as a sine function. 0 indicates RF amplitude. It is a scanning waveform used to scan ions out of the trap in an m / z specific manner.

[0052] Figure 5 An example of a quadrupole linear ion trap with a slit ejection rod in positive ion mode is shown according to this disclosure.

[0053] for Figure 5 For example, as shown in 500, the ion trap 100 can be a quadrupole linear ion trap with a slit ejection rod in positive ion mode. For Figure 5 ,for 0 = 10 V, 1( This can be used to pull ions toward the exit slit. In this respect, since the ions exit the slit with a certain kinetic energy, the final kinetic energy of 12 EV in this example is slightly higher than U0. 2( ) = 0, 3( This can be used to push ions toward the exit slit. Using a push-pull mechanism with two identical waveforms (but different scaling ratios) ensures that the instantaneous ionic kinetic energy of the ejected ions combines with the instantaneous potential energy of the slit rod to generate the desired kinetic energy (e.g., 12 eV in this case) at the intermediate pulser position. Figure 6B As shown.

[0054] about Figure 5 Examples disclosed in this article regarding Figure 5 The function can be performed by keeping U3(t) and U1(t) and V0 constant but scanning ω (e.g., angular frequency). Alternatively, the function disclosed herein... Figure 5 The function can be performed by keeping U3(t) and U1(t) and ω constant but scanning V0.

[0055] Figure 6A The emission time of ions according to an example of this disclosure and the time it takes for them to reach the intermediate pulser after passing through the ion optical transport device are shown. Figure 6B The kinetic energy of an ion at the intermediate pulser position is shown as an example according to this disclosure.

[0056] refer to Figure 6A , Figure 6A The emission times of the ions are shown (e.g., 射出 (the time it takes for ions to pass through the slit) and the time it takes for them to reach the intermediate pulser at 600 after passing through the ion optical transmission device. Figure 6B The kinetic energy of the ion at the intermediate pulser position at 602 is shown. In this respect, Figure 6B The kinetic energy distribution in the detector is not the total kinetic energy, but the energy in the direction perpendicular to the acceleration force vector (i.e., the kinetic energy that produces the TOF natural angle and determines whether an ion will hit the TOF detector).

[0057] Figure 7 An example of ions according to this disclosure is shown being positively charged to enter ion trap 100, exit the ion trap, and be accelerated into a TOF mass analyzer.

[0058] refer to Figure 7 The incident ions entering the ion trap 100 are shown at 700, the ion direction within the ion optical transport device 102 is shown at 702, and the acceleration direction within the TOF mass analyzer (not shown) is shown at 704.

[0059] Figure 8 An example according to this disclosure is shown for an ion trap 100, the number of RF cycles required for the ratio of the standard deviation to the average kinetic energy of ions after passing through the ion optical transport device to an acceptable value.

[0060] refer to Figure 8 The simulation illustrates the number of RF cycles required to achieve an acceptable ratio (e.g., 3%) between the standard deviation and the average kinetic energy of ions after passing through an ion optical transport device. In this regard, Figure 8 The RF cycle number is defined as the number of RF cycles an ion experiences between its maximum electric field RF amplitude (e.g., 300 V / mm shortly after passing through the slit) and the point where the electric field amplitude decays to 1 / e of its maximum value.

[0061] Figure 9 A separate electrode according to an example of this disclosure is shown, including at least one electrode (e.g., "scanning lens" or "lens 1") for applying a scan waveform and an electrode for applying an RF waveform.

[0062] Figure 5 Examples include adding the scan waveform U1(t) and the RF waveform V(t)*cos(wt), and then applying the summed waveform to the bar with the slit. In this regard, Figure 9Examples include a scanning technique that avoids summing U1(t) and the RF waveform via a circuit by using separate electrodes. Furthermore, Figure 9 Examples include variable amplitude of the RF waveform V(t). For instance, one electrode 900 (also labeled “rod”) includes the application of a scanning waveform (e.g., “scanning lens”), while another set of electrodes 902A, 902B and 904A, 904B include the application of an RF waveform. Figure 9 This example can utilize field penetration from the scanning lens to penetrate to the center of the device through a slit in the RF-carrying electrode (as shown at 906). Furthermore, as shown at 908, an RF amplitude ramp change (V(t)) can be performed during the scan output to avoid fragmentation of low-mass ions.

[0063] therefore, Figure 9 Examples may include at least one lever, which includes a lever with a slit (e.g., electrode 900), to which a scanning voltage waveform is applied. Furthermore, the at least one lever may include a first set of levers (e.g., electrodes 902A and 902B), which includes a lever with a slit (e.g., electrode 902B), to which a first RF waveform is applied. Additionally, the at least one lever may include a second set of levers (e.g., electrodes 904A and 904B), to which a second RF waveform is applied.

[0064] Furthermore, the slit rod (e.g., electrode 902B) to which the first RF waveform is applied can represent the internal slit rod. The slit rod (e.g., electrode 900) to which the scan voltage waveform is applied can be arranged behind the internal slit rod relative to the center of the ion trap to pull ions out from the center of the ion trap.

[0065] therefore, Figure 9 The configuration may include at least one slit in the RF-carrying "inner" electrode 902B, and a scanning electrode 900 "behind" the RF electrode with the slit, wherein a scanning voltage is applied to the scanning electrode. This configuration allows ions to be pulled out from the center of the ion trap. Alternatively, ions can be ejected from the other side of the ion trap, for example, by replacing electrode 902A with the RF-carrying electrode and the scanning electrode in front of the RF electrode with the slit (where a scanning voltage is applied). Further, the ion trap may include a push / pull configuration, wherein ions are ejected from the other side of the ion trap by replacing electrode 902A as described above and by arranging electrodes 900 and 902B as shown.

[0066] Figure 10 An example according to this disclosure is shown. Figure 9 Further details on the operation of the separation electrode.

[0067] refer to Figure 10The diagram shows the sum of the effective potentials for three different mass-to-charge ratios (m / z = 300 Th at 1000, m / z = 1000 Th at 1002, and m / z = 3000 Th at 1004), and the potentials generated by applying a set of different scan voltages to the scanning lens. For higher mass-to-charge ratios, a lower scan voltage can be used to achieve a total potential without local minima. Therefore, if the scan voltage is applied in a ramp-like manner from low to high scan voltage, the higher mass-to-charge ratio will exit through the slit in electrode 900 before being compared with the lower mass-to-charge ratio.

[0068] The content described above is an example and some variations thereof. The terminology, descriptions, and figures used herein are illustrative only and are not intended to be limiting. Many variations are possible within the spirit and scope of the subject matter, which is intended to be defined by the following claims and their equivalents, wherein all terms are to be interpreted in their broadest reasonable sense unless otherwise stated.

Claims

1. An ion trap, comprising: An ion trap controller is used to apply a trapping potential and a scanning voltage waveform to at least one electrode to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions. The ion trap described herein comprises a linear construction, and The ions emitted from the ion trap are perpendicular to the axis of the ion trap.

2. The ion trap according to claim 1, wherein the ions comprise a mass-to-charge ratio in the range of 100 to 3000.

3. The ion trap according to claim 1, The linear construction mentioned above includes a linear quadrupole construction. The ion trap includes at least one rod containing a slit, and The at least one rod comprises four rods, the four rods including the at least one rod containing a slit having a radio frequency (RF) trapping potential applied to the four rods.

4. The ion trap according to claim 1, The linear construction mentioned above includes a linear quadrupole construction. The ion trap includes at least one rod containing a slit, and The at least one rod comprises four rods, the four rods including the at least one rod containing a slit having a radio frequency (RF) trapping potential applied to two rods.

5. The ion trap according to claim 1, The linear construction mentioned above includes a linear quadrupole construction, and The ion trap includes at least one rod, and the at least one rod includes two rods for ion ejection between two rods.

6. The ion trap according to claim 1, The linear construction mentioned above includes a linear hexapole construction, and The ion trap includes at least one rod, and the at least one rod includes an exit rod with a slit.

7. The ion trap according to claim 1, The linear construction mentioned above includes a linear hexapole construction, and The ion trap includes at least one rod, and the at least one rod includes two rods for ion ejection between two rods.

8. The ion trap according to claim 1, The ion trap includes at least one rod, the at least one rod including a slit rod, on which a scanning voltage waveform is applied. The at least one lever includes a first set of levers, the first set of levers including a slit lever to which a first radio frequency (RF) waveform is applied, and The at least one rod includes a second set of rods, and a second radio frequency waveform is applied to the second set of rods.

9. The ion trap according to claim 8, The slit rod to which the first radio frequency waveform is applied represents the slit rod on the inner side, and The slit rod, to which the scanning voltage waveform is applied, is positioned behind the inner slit rod relative to the center of the ion trap, so as to pull ions out from the center of the ion trap.

10. An ion trap, comprising: A three-dimensional quadrupole structure includes two end cap electrodes, one of which includes an inlet opening and the other includes an outlet opening, wherein the three-dimensional quadrupole structure also includes a central ring electrode. as well as An ion trap controller is configured to apply a trapping potential and a scanning voltage waveform to at least one of the end cap electrode and the central ring electrode to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions.

11. The ion trap of claim 10, wherein the ions comprise a mass-to-charge ratio in the range of 100 to 3000.

12. A component comprising: Ion traps, including three-dimensional quadrupole or linear structures, are used to sequentially release higher mass-to-charge ratio ions before lower mass-to-charge ratio (m / z) ions; as well as An ion optical transport device used to transport sequentially released ions to an ion accelerator. The ion accelerator is used to accelerate ions from the ion optical transport device.

13. The component according to claim 12, The linear construction mentioned above includes a linear quadrupole construction. The linear configuration described herein includes at least one rod, the at least one rod comprising a rod with a slit, and The at least one of the bars includes four bars, the four bars including the bar with the slit having a radio frequency (RF) capture potential applied to the four bars.

14. The component according to claim 12, The linear construction mentioned above includes a linear quadrupole construction. The linear configuration described herein includes at least one rod, the at least one rod comprising a rod with a slit, and The at least one of the bars comprises four bars, the four bars including the bar with the slit having a radio frequency (RF) capture potential applied to two bars.

15. The component according to claim 12, The linear construction mentioned above includes a linear quadrupole construction, and The linear configuration described therein includes at least one rod, the at least one rod comprising two rods for ion ejection between two rods.

16. The component according to claim 12, The linear construction mentioned above includes a linear hexapole construction, and The linear configuration described therein includes at least one rod, the at least one rod including an exit rod with a slit.

17. The component according to claim 12, The linear construction mentioned above includes a linear hexapole construction, and The linear configuration described therein includes at least one rod, the at least one rod comprising two rods for ion ejection between two rods.

18. The component according to claim 12, The three-dimensional quadrupole configuration includes two end cap electrodes, one of which includes an inlet opening, and the other includes an outlet opening. The three-dimensional quadrupole configuration also includes a central ring electrode.

19. The assembly of claim 12, wherein the ion trap further comprises an ion trap controller for applying a trapping potential and a scanning voltage waveform to at least one electrode operably connected to at least one rod to sequentially release higher mass-to-charge ratio ions prior to lower mass-to-charge ratio (m / z) ions.

20. The component according to claim 12, The ion accelerator is used to accelerate ions from the ion optical transmission device in a direction perpendicular to the ion beam entering the ion trap and also perpendicular to the direction of the ion beam in the ion optical transmission device.

Images