Bent multi-pole collision reaction tank of inductively coupled plasma mass spectrometer

Abstract

A curved multipole collision reaction cell for an inductively coupled plasma mass spectrometer, comprising: a housing comprising a cell inlet, a cell outlet disposed opposite the cell inlet along a longitudinal axis of the housing, and a gas supply port in communication with an internal structure of the housing; and a curved multi-pole ion guide disposed inside the housing along a longitudinal axis of the housing, the curved multi-pole ion guide configured to generate an RF confinement field effective to constrain ions in a radial direction orthogonal to the longitudinal axis of the housing, while the curved multi-pole ion guide is disposed inside the housing along the longitudinal axis of the housing, and the curved multi-pole ion guide is configured to generate an RF confinement field effective to constrain ions in a radial direction orthogonal to the longitudinal axis of the housing. And separating neutral substances from photons and ions. In addition, by adopting the plasma mass spectrometry system of the collision reaction tank provided by the invention, the instrument volume of a mass spectrometer can be greatly reduced, and miniaturization is realized.

Description

Technical Field

[0001] The invention relates to the technical field of inductively coupled plasma mass spectrometers, in particular to a bent multipole collision reaction cell of an inductively coupled plasma mass spectrometer. Background Art

[0002] The typical structure of an inductively coupled plasma mass spectrometry (ICP-MS) system is as follows: Figure 1 As shown, a plasma-based ion source is included; the ion source is used to generate plasma to break the molecules of the sample into atoms and then ionize the atoms to prepare for elemental analysis. In typical operation, the liquid sample is atomized, that is, converted into an aerosol (fine spray or mist) by a gas-driven (usually argon) nebulizer 401, and the coarse aerosol is removed in the nebulization chamber 402, and the remaining fine aerosol is guided into the plasma generated by the plasma source. The plasma source is often configured as a flow-through plasma torch 403 with two or more concentric tubes. Typically, the plasma-forming gas (argon) flows through the inner tube of the torch and is excited into a plasma by a suitable energy source, such as a radio frequency (RF) powered load coil 404. The aerosol flows through the coaxial central tube of the torch 403 and is emitted into the plasma generated, and exposure to the plasma will break the sample molecules into atoms, or alternatively partially break the sample molecules into molecular fragments and ionize the atoms or molecular fragments; these analyte atoms or molecular fragments are ionized to generate an ion beam. Since these ions are not generated in the vacuum region, they gradually transition to the high vacuum region through the sampling cone 405 and the skimmer cone 406. After entering the high vacuum region, the ion beam is focused by the extraction lens group 407 and then enters the off-axis or deflection lens group 408. Figure 1The working principle of ICP-MS is explained by taking the off-axis lens as an example. After the ions pass through the off-axis or deflection lens group 408, they are separated from the photons and neutral substances, and then enter the collision reaction cell 412 through the collision reaction cell entrance focusing lens 410 and the collision reaction cell entrance lens 411. There is also a sliding valve 409 between the off-axis lens group 408 and the collision reaction cell focusing lens. When the instrument is in standby mode, the valve is closed to keep the subsequent components in a higher vacuum environment. In the analysis state, the valve will automatically open. After eliminating interfering ions through collision or reaction, the ion beam is decoupled from the axis by the off-axis lens group 413 at the exit of the collision reaction cell. The second decoupling can eliminate the influence of neutral substances in the collision reaction cell on subsequent mass screening and improve the signal-to-noise ratio. After the secondary off-axis, the ion beam enters the mass analyzer 415; the mass analyzer generally adopts a quadrupole structure or other analyzers such as a sector magnetic field, a time-of-flight (TOF) analyzer, etc., and applies an alternating electric field, or a combination of an electric field and a magnetic field, so that the ionized ions are spectrally decomposed according to their mass-to-charge ratio m / z; the quadrupole mass analyzer generally also has a pre-quadrupole 414. After passing through the mass analyzer 415, the ion detector 416 is enabled to count each type of ion of a given m / z ratio reaching the ion detector from the mass analyzer, and the intensity of each peak indicates the concentration (or abundance) of the corresponding element of the sample.

[0003] In addition to the above-mentioned inductively coupled plasma mass spectrometer composed of a single quadrupole mass analyzer, in order to improve the ability to eliminate interference, a quadrupole mass analyzer can be added before the collision reaction cell to pre-separate the ion beam entering the collision reaction cell. Only ions with selected mass numbers can enter the subsequent collision reaction cell to greatly improve the efficiency of the collision reaction. This is called a triple quadrupole inductively coupled plasma mass spectrometer, such as Figure 2 shown.

[0004] The plasma used as the ion source of ICP-MS cannot decompose all the components in the sample into ions. Some undecomposed neutral substances will be introduced into the subsequent collision reaction cell and quadrupole through the interface along with the ion beam. At the same time, the high-temperature plasma will also produce strong photons. These neutral substances will contaminate the subsequent ion mirror and collision reaction cell on the one hand, and will also produce new interfering ions when colliding with the collision reaction gas in the collision reaction cell on the other hand. Photons will also produce a lot of detection noise. Therefore, effective means are needed to separate neutral substances and photons from analyte ions before the ion beam enters the collision reaction cell.

[0005] The separation of neutral species and photons from analyte ions is done by Figure 1 , Figure 2In addition to the off-axis method shown in , it is known that in the ICP-MS system, a 90-degree deflection method can be used between the ion source and the collision reaction cell, that is, a 90-degree deflection ion guide device can be used to separate the neutral substances and photons from the analyte ions. Regardless of the off-axis method or the 90-degree deflection method, the photons and neutral substances generated in the plasma can be separated from the ion beam, and the ion beam continues to fly into the collision reaction cell.

[0006] Existing inductively coupled plasma mass spectrometers all use linear collision reaction cells, and the number of multipoles includes quadrupoles, hexapole rods, octopole rods, etc. However, for the existing collision reaction cells in the prior art, on the one hand, the linear collision reaction cell cannot effectively separate the newly produced neutral substances in the reaction or collision, and these neutral substances will continue to consume the collision or reaction gas, and even collide or react with the ions to be measured, resulting in a decrease in the efficiency of the collision reaction; on the other hand, the linear multipole collision reaction cell cannot effectively reduce the volume of the vacuum chamber, resulting in a large overall volume of the instrument, which is difficult to achieve miniaturization. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a curved multipole collision reaction cell of an inductively coupled plasma mass spectrometer, in which the poles of the collision reaction cell are set to a curved shape to further separate neutral substances and ions to be measured, and the instrument volume of the mass spectrometer is greatly reduced to achieve miniaturization.

[0008] The present invention provides a bent multipole collision reaction cell for an inductively coupled plasma mass spectrometer, characterized in that it comprises:

[0009] a housing including a pool inlet, a pool outlet disposed opposite the pool inlet along a longitudinal axis of the housing, and a gas supply port communicating with an internal structure of the housing; and

[0010] a curved multipole ion guide disposed inside the housing along the longitudinal axis of the housing, the curved multipole ion guide being configured to generate an RF confinement field effective to confine ions in a radial direction orthogonal to the longitudinal axis of the housing, while separating neutral species and photons from the ions;

[0011] The curved multipole ion guide comprises a plurality of elongated rod electrodes, each of which is a curved structure.

[0012] Furthermore, the plurality of rod electrodes are located at a predetermined radial distance orthogonal to the longitudinal axis of the shell, the plurality of rod electrodes are spaced apart from each other in the circumferential direction around the longitudinal axis, and define the entrance and exit of the curved multipole ion guide; the plurality of rod electrodes are parallel to each other.

[0013] Furthermore, the longitudinal axis of the rod electrode is in the shape of an arc, a zigzag line, or a combination of an arc and an arc, or a combination of an arc and a zigzag line.

[0014] Furthermore, a small section at the front end and / or rear end of the rod electrode is a straight rod to align ions.

[0015] Further, a set of the rod electrodes spaced apart is configured to apply an RF+ potential superimposed on the DC bias potential (U), and another set of the rod electrodes spaced apart is configured to apply an RF- potential superimposed on the DC bias potential (U);

[0016] The RF+ potential and the RF- potential are radio frequency signals with the same frequency and amplitude but opposite phases, thereby generating an RF confinement field for ions.

[0017] Furthermore, a negative DC potential barrier is generated at the outlet of the multipole ion guide so that ions can be smoothly guided out of the collision reaction cell.

[0018] Furthermore, the number of the rod electrodes is 2N, wherein N is an integer and N≥2.

[0019] Furthermore, the rod electrode is one of a round rod, a square rod, a hyperbolic rod or a concave rod.

[0020] Furthermore, it also includes:

[0021] an inlet ion mirror, disposed at a pool inlet side of the housing; and

[0022] The outlet ion mirror is arranged at the pool outlet side of the shell.

[0023] The invention also provides an inductively coupled plasma mass spectrometry analysis system with a curved multipole collision reaction cell.

[0024] The curved multipole collision reaction cell of the inductively coupled plasma mass spectrometer provided by the present invention sets the poles of the collision reaction cell into a curved shape, which can constrain the ions entering the collision reaction cell, and the neutral substances produced in the collision reaction cell are not constrained by the electric field, so they will not change their original flight direction with the bending of the rod electrodes, and therefore can be separated from the ions. In this way, it can be avoided that the neutral substances continue to consume collision or reaction gas when flying in the same direction as the ion beam, and even collide or react with the ions to be measured. This part of the neutral substances is discharged by the molecular pump after leaving the collision reaction cell. A small section of straight rod electrodes is set at the front and rear ends of the rod electrodes, which can focus the ion beam passing through this section, so that it flies from the center of the multiple rod electrodes into the subsequent curved section in a straight direction or flies out from the central small hole of the collision reaction cell outlet. The plasma mass spectrometry analysis system using the collision reaction cell provided by the present invention can greatly reduce the instrument volume of the mass spectrometer and achieve miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a typical inductively coupled plasma mass spectrometry (ICP-MS) system in the prior art;

[0026] Figure 2 It is a schematic diagram of a triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS) system in the prior art;

[0027] Figure 3 It is a schematic diagram of an explosion of a bent multipole collision reaction cell of an inductively coupled plasma mass spectrometer of the present invention;

[0028] Figure 4 is a circuit diagram of the rod electrode of the present invention;

[0029] Figure 5 It is a schematic diagram of an inductively coupled plasma mass spectrometry (ICP-MS) system with a bent multipole collision reaction cell according to the present invention;

[0030] Figure 6 It is a schematic diagram of ion flight trajectory simulation of an inductively coupled plasma mass spectrometry (ICP-MS) system with a bent multipole collision reaction cell of the present invention;

[0031] Figure 7 It is a schematic diagram of a triple quadrupole inductively coupled plasma mass spectrometry analysis system with a bent multipole collision reaction cell of the present invention;

[0032] Figure 8 It is a schematic diagram of another triple quadrupole inductively coupled plasma mass spectrometry analysis system with a bent multipole collision reaction cell of the present invention.

[0033] In the figure:

[0034] 10. Shell; 1001. Pool inlet; 1002. Pool outlet;

[0035] 20. bent multipole ion guide; 201. rod electrode;

[0036] 30. Entrance ion mirror;

[0037] 40. Export ion mirror.

[0038] 50. Fixed ring;

[0039] 60. Insulating gasket;

[0040] 70. Electrode;

[0041] 80. RF+ connection electrode;

[0042] 90. RF-connected electrodes. DETAILED DESCRIPTION

[0043] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0044] In the description of the present invention, it should be understood that the terms "longitudinal", "radial", "orthogonal", "opposite", "one end", "the other end", etc. used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] like Figure 3 As shown, the present invention provides a curved multipole collision reaction cell of an inductively coupled plasma mass spectrometer, comprising a housing 10, a curved multipole ion guide 20, an entrance ion mirror 30 and an exit ion mirror 40; the curved multipole ion guide 20 is arranged inside the housing 10 along the longitudinal axis of the housing 10, and the curved multipole ion guide 20 is connected to the housing 10 through a fixing ring 50. The longitudinal axis refers to the axis of the housing 10 in the length direction.

[0047] Specifically, the housing 10 includes a pool inlet 1001 and a pool outlet 1002 arranged along the longitudinal axis of the housing 10 opposite to the pool inlet 1001; a gas supply port (not shown in the figure) is provided in the middle of the housing 10 for collision or reaction gas to enter the interior of the housing 10. The outer end of the gas supply port is connected to a device for controlling gas flow (such as a proton flowmeter) and a switch for selecting a gas type (such as a solenoid valve), and the control range of the gas flow can be 0-20 ml / min.

[0048] The housing 10 is preferably made of metal material, and has a corresponding structure inside for fixing the curved multipole ion guide 20. Insulating gaskets 60 for fixing the entrance ion mirror 30 and the exit ion mirror 40 are provided at both ends of the housing 10.

[0049] The curved multipole ion guide 20 is configured to generate an RF confinement field that effectively confines ions in a radial direction orthogonal to the longitudinal axis of the housing 10 , while separating neutral species and photons from the ions.

[0050] The curved multipole ion guide 20 includes a plurality of elongated rod electrodes 201, each of which is a curved structure. The curved shape and degree of the rod electrodes 201 can be adjusted according to factors such as the spatial arrangement of the plasma mass spectrometer; for the curved shape, the longitudinal axis of the rod electrode 201 can be a broken line, an arc, a combination of arcs, a combination of arcs and straight lines, etc.; for the degree of curvature, the curvature of the rod electrode 201 can be small, for example, the angle between the starting end and the end end is small; the curvature of the rod electrode 201 can also be large, for example, bent into an S shape. Figure 3 As shown, the rod electrode 201 is an arc with a bending angle of 90 degrees; Figure 8 As shown, the rod electrode 201 is in the form of an arc with a bending angle of 180 degrees.

[0051] The plurality of rod electrodes 201 are located at a predetermined radial distance orthogonal to the longitudinal axis of the housing 10, the plurality of rod electrodes 201 are spaced apart from each other in the circumferential direction around the longitudinal axis, and define the inlet and outlet of the curved multipole ion guide 20; the plurality of rod electrodes 201 are parallel to each other. The inlet of the curved multipole ion guide 20 corresponds to the pool inlet 1001, and the outlet of the curved multipole ion guide 20 corresponds to the pool outlet 1002.

[0052] Preferably, a small section of the front end (i.e., the side close to the pool entrance 1001) of the rod electrode 201 is a straight rod, followed by a curved rod. A small straight section is provided on the side of the rod electrode 201 close to the pool entrance 1001, so that ions entering the reaction pool from the entrance ion mirror 30 can be collimated.

[0053] Furthermore, a small section of the rear end (ie, the side close to the cell outlet 1002 ) of the rod electrode 201 is a straight rod, so that the ions can be aligned to facilitate entering the outlet ion mirror 40 .

[0054] The number of the rod electrodes 201 is 2N (N is an integer and N≥2). Preferably, the curved multipole ion guide 20 can be a quadrupole, a hexapole, an octopole, a decapole, a dodecapole, or the like.

[0055] The rod electrode 201 is a round rod, a square rod, a hyperbolic rod, a concave rod, or other suitable shapes.

[0056] The multiple rod electrodes 201 are arranged as a curved structure, which can constrain the ions entering the rod electrodes 201, while the neutral substances produced in the collision reaction pool are not constrained by the electric field, and thus will not change their original flight direction as the rod electrodes 201 are bent, and therefore can be separated from the ions. In this way, it is possible to avoid the neutral substances from continuing to consume collision or reaction gas when flying in the same direction as the ion beam, or even colliding or reacting with the ions to be measured, and this part of the neutral substances is discharged by the molecular pump after leaving the collision reaction pool. Optionally, a small section of straight rod electrodes is arranged at the front and rear ends of the rod electrodes 201, the purpose of which is to focus the ion beam passing through this section, so that it flies from the center of the multiple rod electrodes 201 into the subsequent curved section in a straight direction or flies out from the central small hole at the exit of the collision reaction pool.

[0057] The inlet ion mirror 30 is disposed on a side of the cell inlet 1001 of the housing 10 , and the outlet ion mirror 40 is disposed on a side of the cell outlet 1002 of the housing 10 .

[0058] The entrance ion mirror 30 and the exit ion mirror 40 are made of metal, and have a circular hole in the middle for ions to enter and exit, with a hole diameter of 1-10 mm. A negative DC voltage can be applied to the entrance ion mirror 30 and the exit ion mirror 40 to guide ions to enter and leave the collision reaction cell.

[0059] Furthermore, electrodes 70 may be provided on the entrance ion mirror 30 and the exit ion mirror 40 to facilitate application of a DC voltage thereto.

[0060] In some embodiments, Figure 4As shown, the rod electrodes 201 in the curved multipole ion guide 20 are divided into two groups at intervals, wherein the group of rod electrodes 201 at intervals is configured to apply an RF+ potential superimposed on a DC bias potential (U). Specifically, one group of rod electrodes is connected to the RF+ connection electrode 80; the other group of rod electrodes at intervals is configured to apply an RF- potential superimposed on the DC bias potential (U), specifically, the group of rod electrodes is connected to the RF- connection electrode 90. These rod electrodes 201 can be superimposed with a certain DC bias (U) through one or a group of resistors, so as to adjust the kinetic energy of the ions in the collision reaction cell.

[0061] The above RF+ and RF- are radio frequency signals with the same frequency and amplitude and opposite phases (180° difference), and the frequency can be set to 0.1-200MHz, thereby generating an RF confinement field for ions. In this way, the ions collide or react with the gas in the collision reaction cell while moving along the center line of the curved multipole, thereby eliminating the influence of interfering ions. However, the neutral substances produced during the collision or reaction will fly along the straight line of their own flight inertia, and will not be constrained by the electric field and fly along the curve, thereby achieving a complete separation of the ions to be measured and the neutral substances produced in the collision and reaction.

[0062] like Figure 5 As shown, a curved multipole collision reaction cell of an inductively coupled plasma mass spectrometer provided by the present invention is specifically applied to a scenario in an inductively coupled plasma mass spectrometry (ICP-MS) system, that is, an inductively coupled plasma mass spectrometry system with a curved multipole collision reaction cell is shown. The liquid sample is atomized by a gas-driven atomizer 101, that is, converted into an aerosol (fine spray or mist), and the coarse aerosol is removed in the atomization chamber 102, and the remaining fine aerosol is guided to the plasma generated by the plasma source. The plasma source is configured as a flow-through plasma torch 103 having two or more concentric tubes. The plasma forming gas (argon gas) flows through the inner tube of the torch tube and is excited into a plasma by a radio frequency (RF) powered load coil 104, and gradually transitions to a high vacuum region through a sampling cone 105 and a skimmer cone 106. After entering the high vacuum region, the ion beam is focused by the extraction lens group 107 and then enters the off-axis lens group 108 to separate from the photons and neutral substances, and then enters the collision reaction cell through the collision reaction cell entrance focusing lens 110 and the collision reaction cell entrance lens 30. The collision reaction cell is Figure 3The curved multipole collision reaction cell shown in FIG. There is also a sliding valve 109 between the off-axis lens group 108 and the collision reaction cell focusing lens 30. The valve is closed when the instrument is in standby mode to keep the subsequent components in a higher vacuum environment. The valve will automatically open in the analysis mode. After eliminating interfering ions through collision or reaction, the ion beam is decoupled from the axis by the off-axis lens group 40 at the exit of the collision reaction cell. The second decoupling can eliminate the influence of neutral substances in the collision reaction cell on subsequent mass screening and improve the signal-to-noise ratio. The ion beam after the second decoupling enters the mass analyzer 115; the mass analyzer generally adopts a quadrupole structure or other such as a sector magnetic field, a time-of-flight (TOF) analyzer, etc., and applies an alternating electric field, or a combination of an electric field and a magnetic field, so that the ionized ions are spectrally decomposed according to their mass-to-charge ratio m / z. The mass analyzer 115 generally also has a pre-quadrupole 114. After passing through the mass analyzer 115, an ion detector 116 is enabled to count each type of ion of a given m / z ratio reaching the ion detector from the mass analyzer, with the intensity of each peak indicating the concentration (or abundance) of the corresponding element of the sample.

[0063] from Figure 6 It can be seen from the simulated ion flight trajectory that, using the inductively coupled plasma mass spectrometry analysis system with a curved multipole collision reaction cell provided by the present invention, the ion beam is perfectly constrained on the central curve of the multipole ion guide after being focused and entering the curved collision reaction cell, and flies out from the outlet of the collision reaction cell to enter the subsequent mass analyzer for ion screening.

[0064] Figure 7 A triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS) system with a curved multipole collision reaction cell is shown. It can be seen that the length of the instrument can be greatly shortened by using the curved multipole collision reaction cell provided by the present invention, thereby achieving miniaturization of the instrument.

[0065] Figure 8 Another triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS) system with a curved multipole collision reaction cell is shown. In the system, another curved multipole collision reaction cell provided by the present invention is used. In the reaction cell, the angle corresponding to the arc of the longitudinal axis of the plurality of rod electrodes 201 in the curved multipole ion guide 20 is 180 degrees. The advantage of using such a curved multipole collision reaction cell is that the arrangement of the components in the mass spectrometer can be further optimized, thereby further reducing the volume of the mass spectrometer.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present invention. The basic principles, main features and advantages of the present invention are shown and described above. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above preferred embodiments. The embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, so it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention.

[0067] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A bent multipole collision reaction cell for an inductively coupled plasma mass spectrometer, characterized in that: include: a housing including a pool inlet, a pool outlet disposed opposite the pool inlet along a longitudinal axis of the housing, and a gas supply port communicating with an internal structure of the housing; as well as a curved multipole ion guide disposed inside the housing along the longitudinal axis of the housing, the curved multipole ion guide being configured to generate an RF confinement field effective to confine ions in a radial direction orthogonal to the longitudinal axis of the housing, while separating neutral species and photons from the ions; The curved multipole ion guide comprises a plurality of elongated rod electrodes, each of which is a curved structure.

2. The reaction cell according to claim 1, characterized in that The plurality of rod electrodes are located at a predetermined radial distance orthogonal to the longitudinal axis of the shell, the plurality of rod electrodes are spaced apart from each other in the circumferential direction around the longitudinal axis, and define the entrance and exit of the curved multipole ion guide; the plurality of rod electrodes are parallel to each other.

3. The reaction cell according to claim 1, characterized in that The longitudinal axis of the rod electrode is in an arc shape, a zigzag line shape, or a combination of an arc and an arc, or a combination of an arc and a zigzag line shape.

4. The reaction cell according to claim 1, characterized in that A small section at the front end and / or rear end of the rod electrode is a straight rod to align ions.

5. The reaction cell according to claim 1, characterized in that A set of the rod electrodes spaced apart is configured to apply an RF+ potential superimposed on a DC bias potential (U), and another set of the rod electrodes spaced apart is configured to apply an RF- potential superimposed on a DC bias potential (U); The RF+ potential and the RF- potential are radio frequency signals with the same frequency and amplitude but opposite phases, thereby generating an RF confinement field for ions.

6. The reaction cell according to claim 1, characterized in that A negative DC potential barrier is generated at the exit of the multipole ion guide so that ions can be smoothly guided out of the collision reaction cell.

7. The reaction cell according to claim 1, characterized in that The number of the rod electrodes is 2N, wherein N is an integer and N≥2.

8. The reaction cell according to claim 1, characterized in that The rod electrode is one of a round rod, a square rod, a hyperbolic rod or a concave rod.

9. The reaction cell according to claim 1, characterized in that Also includes: an inlet ion mirror, disposed at a pool inlet side of the housing; and The outlet ion mirror is arranged at the pool outlet side of the shell.

10. An inductively coupled plasma mass spectrometry (ICP-MS) system having the bent multipole collision reaction cell according to any one of claims 1 to 9.

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