Rotary collision reaction tank of inductively coupled plasma mass spectrometer

Abstract

The invention relates to the technical field of inductively coupled plasma mass spectrometers, and particularly discloses a rotary collision / reaction cell of an inductively coupled plasma mass spectrometer, the rotary collision / reaction cell comprises a shell and a multi-pole rod ion guider, the shell comprises a cell inlet, a cell outlet and a gas supply port communicated with the internal structure of the shell; a multi-pole rod ion guide is disposed inside the housing along a longitudinal axis of the housing, the multi-pole rod 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, the multi-pole rod ion guide comprising a plurality of elongate rod electrodes, the multiple rod electrodes are arranged in a rotary structure around the longitudinal axis of the shell so as to generate certain torsion on ions entering the rod electrodes and enable the ion beams to rotate and compress according to a set angle while moving forwards in an oscillating mode. According to the invention, the ions can move spirally, so that the mutual collision among the ions is reduced, and the ion transmission efficiency in a collision mode is greatly improved.

Description

Technical Field

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

[0002] The inductively coupled plasma mass spectrometer (ICP-MS) system includes a plasma-based ion source for generating plasma to decompose the molecules of the sample into atoms and then ionize the atoms in preparation for elemental analysis. In typical operation, the liquid sample is atomized, i.e., converted into an aerosol (fine spray or mist) by a gas-driven (usually argon) nebulizer, and the coarse aerosol is removed in the atomization chamber, 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 having two or more concentric tubes, and 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. The aerosol flows through the coaxial central tube of the torch and is emitted into the plasma generated, and exposure to the plasma decomposes the sample molecules into atoms, or alternatively partially decomposes the sample molecules into molecular fragments and ionizes the atoms or molecular fragments.

[0003] The generated analyte ions are extracted from the plasma ion source and guided as an ion beam to a mass analyzer. The generated analyte ions are usually positively charged. The mass analyzer generally adopts a quadrupole structure, or other analyzers such as a sector magnetic field, a time-of-flight (Time of Flight Mass Spectrometer TOF) analyzer, etc., and an alternating electric field, or a combination of electric and magnetic fields, is applied to make the ionized ions spectrally decomposed according to their mass-to-charge ratio (m / z). Then, the ion detector 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.

[0004] The plasma as an ICP-MS ion source, in addition to generating analyte ions, also generates certain interfering ions, which interfere with the analysis of certain types of analytes. Interfering ions can be generated by plasma forming gases (such as argon), matrix components of the sample, solvents / acids included in the sample, or air (oxygen and nitrogen) entrained into the system. For example, interfering ions can be isobaric interfering substances with the same nominal mass as the analyte ions. The detection of these interfering ions and the detection of certain analyte ions result in spectral overlap in the analysis data, thereby reducing the quality of the analysis. Examples of interfering ions include polyatomic ions, such as argon oxide 40Ar35Cl+ and argon 40Ar+, the argon oxide interfering with the iron isotope 75As+, because both ions appear in the mass spectrum with m / z=75, and the argon interfering with the calcium isotope 40Ca+, because both ions appear with m / z=40.

[0005] Known methods for solving the problem of spectrum interference and improving the performance of ICP-MS systems include matrix separation, cold plasma technology, and mathematical correction equations when processing analytical data, all of which have known limitations. To further solve the problem of interfering ions, it is known that a collision / reaction cell is provided between the ion source and the mass analyzer in the ICP-MS system. Mainstream products on the market today are equipped with collision / reaction cells, and multipole rods are installed in the cell. Collision gas or reaction gas is filled in the collision / reaction cell. The use of collision gas (such as helium) depends on kinetic energy discrimination (KED), which can suppress polyatomic ion interference. The analyte ions and polyatomic interfering ions in the cell experience multiple collisions with the collision gas, respectively, and lose kinetic energy (KE) and therefore slow down. However, because the polyatomic ions that produce interference have a larger cross-section than the analyte ions, the polyatomic interfering ions experience more collisions and therefore lose more kinetic energy than the analyte ions. Therefore, kinetic energy discrimination (KED) can be utilized to separate the analyte ions from the polyatomic interfering ions.

[0006] In a conventional multipole collision / reaction cell, the ion beam is focused by the entrance ion lens and enters the cell body through the front aperture of the collision reaction cell. Under the action of the multipole radio frequency, the ions will oscillate between the poles perpendicular to the axis while moving forward along the axial direction, thereby forming a spiral trajectory. The ions will continuously collide with the gas molecules in the cell body during the process of traveling, and the thermal effect of the ions will inevitably change the trajectory of the ions. However, in the existing multipole collision / reaction cell, each pole is a linear structure and is arranged in parallel. The radio frequency signal added to the pole can only cause the ions to oscillate in the direction perpendicular to the axis of the collision / reaction cell, which will cause the ion's running trajectory to be chaotic, thereby causing mutual collisions between ions. Since the mass of the ions is much higher than the mass of the collision gas (generally helium), the mutual collisions between the ions will cause the analyte ions to instantly lose too much kinetic energy, thereby being unable to cross the subsequent DC potential barrier. Therefore, when the current multipole collision / reaction cell uses the KED mode, it will lose more than 70% of the sensitivity under the premise of ensuring a certain intensity ratio of the analyte ions to the interfering ions.

[0007] Existing technologies such as Chinese patent CN103890901B use multiple sets of multipoles or curved multipoles with modified ion inlet end cross-sections to allow more ions to be introduced into the collision reaction cell, thereby improving the sensitivity of the instrument. However, the problems with this technology are: 1. This technology also uses a parallel multipole design, which, like the existing mature collision reaction cells, cannot effectively reduce the mutual collisions between particles and cannot improve the collision reaction efficiency of ions; 2. Since the processing and assembly of the multipoles in the collision reaction cell require very high precision, this technology is complex in design and is very difficult to implement in terms of processing and assembly, which will bring high costs.

[0008] Therefore, an improved collision / reaction cell is needed to control the oscillation and rotation direction of ions in the cell, thereby reducing mutual collisions between ions and improving the efficiency of collision reactions to better solve the interference problem. Summary of the invention

[0009] The technical problem to be solved by the present invention is: how to reduce the mutual collision between ions in the collision reaction cell and improve the ion transmission efficiency.

[0010] In order to solve the above technical problems, the present invention provides a rotating collision reaction cell of an inductively coupled plasma mass spectrometer, comprising:

[0011] 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

[0012] a multipole ion guide disposed inside the housing along a longitudinal axis of the housing, the 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;

[0013] The multipole ion guide comprises a plurality of slender rod electrodes, which are arranged in a rotating structure around the longitudinal axis of the shell to generate a certain torque on ions entering the multipole ion guide and make the ions rotate and compress while oscillating forward.

[0014] Further, 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 a circumferential direction around the longitudinal axis, and define an inlet and an outlet of the multipole ion guide.

[0015] Furthermore, the field diameter at the inlet end of the multipole ion guide is larger than the field diameter at the outlet end; or the field diameter at the inlet end of the multipole ion guide is smaller than the field diameter at the outlet end.

[0016] 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);

[0017] Among them, RF+ and RF- are radio frequency signals with the same frequency and amplitude but opposite phases, and their frequencies are between 1-20 MHz, thereby generating an RF confinement field for ions.

[0018] Furthermore, 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.

[0019] Furthermore, the number of the rod electrodes is 2N, wherein N is an integer and N≥2.

[0020] Furthermore, the rotation angles of the two ends of the rod electrode are θ, wherein 0°<θ<360°.

[0021] Furthermore, the rod electrode is one of a round rod, a square rod, a hyperbolic rod or a concave rod.

[0022] Furthermore, it also includes:

[0023] an inlet ion mirror, disposed at a pool inlet side of the housing; and

[0024] The outlet ion mirror is arranged at the pool outlet side of the shell.

[0025] Compared with the prior art, the rotary collision / reaction cell of an inductively coupled plasma mass spectrometer provided by the present invention has the following beneficial effects:

[0026] The present invention forms a multipole ion guide with a plurality of rod electrodes arranged in a rotating structure around the longitudinal axis of a shell. The rotating structure is adopted, thereby generating a certain torque on the ion beam entering the guide, so that the ion beam is rotated and compressed according to a set angle while oscillating forward, so that the ions are spirally moved in the collision / reaction cell according to the rotation direction of the rod electrodes, thereby reducing mutual collisions between ions, inhibiting the rapid decay of the kinetic energy of the ions to be measured, and greatly improving the ion transmission efficiency in the collision mode; in addition, due to the use of a rotating multipole ion guide, while providing axial initial kinetic energy to the ions, it will continue to provide rotational kinetic energy consistent with the rotation direction of the multipole ions, thereby improving the initial kinetic energy of the ions and greatly reducing the generation of zero kinetic energy ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of an explosion of a rotating collision reaction cell of an inductively coupled plasma mass spectrometer described in the present invention.

[0028] Figure 2 It is a simplified assembly diagram of the housing and the multipole ion guide of the present invention.

[0029] Figure 3 Schematic diagram of the structure of the rod electrode of the present invention.

[0030] Figure 4 is a side view of the rod electrode of the present invention.

[0031] Figure 5 It is a circuit demonstration diagram of the rod electrode described in the present invention.

[0032] In the figure:

[0033] 10. Shell; 101. Pool inlet; 102. Pool outlet; 103. Gas supply port;

[0034] 20. Multipole ion guide; 201. Rod electrode;

[0035] 30. Entrance ion mirror;

[0036] 40. Export ion mirror.

[0037] 50. Fixed ring;

[0038] 60. Insulating gasket;

[0039] 70. RF+ connection electrode;

[0040] 80. RF-connected electrodes;

[0041] 90. Resistance. DETAILED DESCRIPTION

[0042] 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.

[0043] 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.

[0044] 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.

[0045] like Figure 1-5 As shown, this embodiment provides a rotating collision reaction cell of an inductively coupled plasma mass spectrometer, including a shell 10, a multipole ion guide 20, an entrance ion mirror 30 and an exit ion mirror 40, the multipole ion guide 20 is arranged inside the shell 10 along the longitudinal axis of the shell 10, and the multipole ion guide 20 is connected to the shell 10 by a fixing ring 50.

[0046] In a specific example, the shell 10 includes a pool inlet 101, a pool outlet 102 arranged opposite to the pool inlet 101 along the longitudinal axis of the shell 10, and a gas supply port 103 connected to the internal structure of the shell 10, the entrance ion mirror 30 is arranged on the side of the pool inlet 101 of the shell 10, and the exit ion mirror 40 is arranged on the side of the pool outlet 102 of the shell 10.

[0047] The 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. The multipole ion guide 20 includes a plurality of elongated rod electrodes 201, which are arranged in a rotating structure around the longitudinal axis of the housing 10 to generate a certain torque on the ions entering the rod electrodes 201 and rotate and compress the ion beam according to a set angle while oscillating forward. The multiple rod electrodes 201 adopt a rotating structure, which can generate a certain torque on the ion beam entering the multipole ion guide 20, so that the ion beam is rotated and compressed at a set angle while oscillating forward, so that the ions move in a spiral manner in the collision / reaction pool according to the rotation direction of the rod electrodes 201, thereby reducing the mutual collision between ions, suppressing the rapid decay of the kinetic energy of the ions to be measured, and greatly improving the ion transmission efficiency in the collision mode; in addition, due to the use of a rotating multipole ion guide 20, while providing the ions with axial initial kinetic energy, it will continue to provide the ions with rotational kinetic energy consistent with the rotation direction of the multiple rod electrodes 201, thereby improving the initial kinetic energy of the ions and greatly reducing the generation of zero kinetic energy ions.

[0048] In the above examples, the longitudinal axis refers to the axis of the housing 10 in the length direction.

[0049] In the above example, the number of the rod electrodes 201 is 2N (N is an integer and N≥2). Preferably, the multipole ion guide 20 can be a quadrupole, a hexapole, an octopole, a decapole, a dodecapole, or the like.

[0050] In some embodiments, each rod electrode 201 is arranged at a certain inclination angle, and the rotation angle of the rod electrode 201 is θ, where 0°<θ<360°; the rotation angle means that one end of the rod electrode 201 is fixed, and the other end is rotated around the longitudinal axis by a certain angle, so that the rod electrode 201 forms a rotating structure with an inclination angle.

[0051] In some embodiments, 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 multipole ion guide 20. The inlet of the multipole ion guide 20 corresponds to the cell inlet 101, and the outlet of the multipole ion guide 20 corresponds to the cell outlet 102.

[0052] In some embodiments, the field diameter at the entrance of the multipole ion guide 20 is larger than that at the exit, or the field diameter at the entrance of the multipole ion guide 20 is smaller than that at the exit, wherein the field diameter refers to the diameter of the inscribed circle of the multipole.

[0053] In some embodiments, Figure 5 As shown, the rod electrodes 201 are divided into two groups at intervals, wherein one group of rod electrodes 201 at intervals is configured to apply an RF+ potential superimposed on a DC bias potential (U), specifically, the group of rod electrodes 201 is connected to an RF+ connection electrode 70; the other group of rod electrodes 201 at intervals is configured to apply an RF- potential superimposed on a DC bias potential (U), specifically, the group of rod electrodes 201 is connected to an RF- connection electrode 80. These rod electrodes 201 can be superimposed with a certain DC bias (U) through one or a group of resistors 90, so as to adjust the kinetic energy of ions in the collision / reaction cell, as shown in FIG. Figure 5 shown.

[0054] In the above example, RF+ and RF- are radio frequency signals with the same frequency and amplitude and opposite phases (180° difference), and their frequencies are between 1-20MHz, thus generating an RF confinement field for the ions. In this way, the ions oscillate and rotate forward while colliding with the gas in the collision / reaction cell. Interfering ions encounter more collisions due to their larger cross-sectional area, thus losing more kinetic energy and therefore unable to cross the subsequent DC voltage barrier; ions of the element to be measured encounter fewer collisions due to their small cross-sectional area, and although they lose some kinetic energy, they can still cross the subsequent DC voltage barrier, thus achieving the separation of the ions to be measured and the interfering ions.

[0055] In some embodiments, the RF confinement field generated in the multipole ion guide 20 is used to confine ions in a radial direction orthogonal to the longitudinal axis, generating a negative DC potential barrier at the exit of the multipole ion guide 20 so that ions can be smoothly guided out of the collision / reaction cell.

[0056] In some embodiments, the rod electrode 201 is one of a round rod, a square rod, a hyperbolic rod, or a concave rod.

[0057] In some embodiments, the shell 10 is preferably made of metal material, has a corresponding structure inside for fixing the poles, and is provided with insulating gaskets 60 at both ends for fixing the entrance ion mirror 30 and the exit ion mirror 40. A gas supply port 103 is provided in the middle of the shell 10 for collision or reaction gas to enter the interior of the shell 10, and a device for fixing the multipole ion guide 20 is provided in the middle of the shell 10.

[0058] In the above example, the outer end of the gas supply port 103 is connected to a device for controlling gas flow (such as a proton flowmeter) and a switch for selecting the gas type (such as a solenoid valve), and the control range of the gas flow is 0-20 ml / min.

[0059] In some embodiments, the entrance ion mirror 30 and the exit ion mirror 40 of the collision / reaction cell are made of metal, with circular holes in the middle for ions to enter and exit, and the hole diameter is 1-10 mm. A negative DC voltage is applied to the lens to guide ions to enter and leave the collision reaction cell.

[0060] In this embodiment, the multipole ion guide 20 adopts a rotational arrangement. Compared with the parallel arrangement of the multipole, while the ions oscillate in a direction perpendicular to the axial direction, a certain rotational potential energy is applied, so that the ions oscillate forward in the collision / reaction pool in the direction of the multipole rotation, which greatly reduces the mutual collisions between the ions, thereby suppressing the rapid decay of the kinetic energy of the ions to be measured.

[0061] This embodiment can improve the sensitivity in the kinetic energy discrimination (KED) mode. The effect of this embodiment is demonstrated by calculating the ion kinetic energy of the analyte ions and the interfering ions.

[0062] Consider two ion species A (atomic analyte ion) and B (polyatomic ion interfering with A). The B ion has the same mass or m / z ratio as the A ion, but is larger than the A ion. It is assumed that the B ion collides with gas molecules twice as often as the A ion due to its larger size (larger collision cross-sectional area).

[0063] At the entrance of the collision cell, the A and B ions have the same initial kinetic energy E given by the instrument operating conditions. i . Initial kinetic energy E i Typically about 20 eV. In the collision cell, both A and B ions are gradually decelerated each time they collide with collision gas molecules. In the hard sphere collision model, the final kinetic energy (the kinetic energy that the ions have at the exit of the collision cell) is approximately given by the following equation:

[0064]

[0065] where m1 and m2 are the masses of the ion and gas molecule, respectively, and N is the number of collisions the ion undergoes in the collision cell; E i is the initial kinetic energy.

[0066] Since the N of B ions is greater than that of A ions on average, the E of B ions f Less than the E of A ion f .

[0067] For example, according to the above formula, A=75As + Ion (m1 = 75u) collides with helium gas (m2 = 4u) 15 times and B = 40Ar35Cl + The approximate final energy E of ion (m1 = 75u) colliding with the helium gas 30 times f / A and Ef / B, as follows:

[0068] E f / A=0.22E i ,and

[0069] E f / B=0.048E i ,

[0070] When E i =21-25eV, E f / A=4.6-5.5eV and E f / B=1.0-1.2eV.

[0071] Therefore, by setting a potential barrier with a height of 3 eV after the collision cell, low energy B ions are blocked by the potential barrier while higher energy A ions are able to cross the potential barrier. In this way, the analyte ion A is selectively detected when the interfering ion B is removed from the ion beam after the potential barrier. This technique is called kinetic energy discrimination (KED), as described elsewhere in this article. Since the flow rate of the collision gas entering the collision / reaction cell is adjustable, it is possible to analyze the parameters and optimize the collision gas flow rate by observing the signal intensity ratio of the ion intensity to be measured at a certain concentration to the interfering ion.

[0072] As mentioned above, in a general collision / reaction cell's multipole ion guide, the poles are evenly divided and arranged in parallel. Therefore, when the ion beam enters the cell, the radio frequency on the multipole only produces oscillations perpendicular to the axis of the cell for the incoming ions, while the spiral direction of the ions is uncontrolled. When there is no collision gas in the collision / reaction cell, the running speeds of these ions are basically the same, so there are few chances of collision between them. However, when a collision gas with a certain flow rate is introduced into the collision cell (usually 3-8 ml / min of helium), these gas molecules continuously collide with the ions in the ion beam, causing the running direction, speed and trajectory of the ions to change. Since the ion beam contains a lot of interfering ions and sample matrix ions, collisions occur between the ions to be measured and these ions. For example, if the A ions and B ions in the above example only collide with helium molecules, their kinetic energy will become 22% of the initial kinetic energy after 15 collisions. However, if it is a collision between the A ions and the B ions, the kinetic energy of the ions will drop by half after one collision (which can be calculated according to the above formula). If the ions to be measured collide with ions with a larger mass number than themselves, the kinetic energy lost will be even greater. If they collide with helium molecules more than 12 times, the final ion kinetic energy will be lower than 3eV, and thus they will be blocked by subsequent potential barriers together with the interfering ions, resulting in reduced measurement sensitivity.

[0073] The present invention uses a unique multipole collision / reaction cell with a rotational arrangement. After the ion beam enters the collision / reaction cell, since the multipole ion guide is rotationally arranged, in addition to providing the ion beam with an oscillation constraint perpendicular to the axial direction, it can also provide the ion beam with a rotational torque consistent with the rotation direction of the multipole, so that the ion beam always maintains a unified rotation direction under the action of the torque, greatly reducing mutual collisions between ions, improving the passing efficiency of ions to be measured in the collision mode, and thus improving the sensitivity of the instrument in the collision mode.

[0074] This embodiment can improve the initial kinetic energy of ions and eliminate zero kinetic energy ions. For the multipole ion guide arranged in parallel, the initial kinetic energy of ions when entering the collision / reaction pool is mainly the kinetic energy generated by the ion source plus the kinetic energy generated by the negative bias of the multipole ion guide, which is generally in the axial direction. After a series of collisions, the kinetic energy of the ions continues to decrease. A small number of ions completely lose their axial kinetic energy due to too many collisions. On the one hand, these ions are prone to collisions with subsequent ions, and on the other hand, they can only be taken out by the collision gas, which will directly affect the efficiency of collision and reaction.

[0075] In summary, the embodiment of the present invention provides a rotating collision / reaction cell of an inductively coupled plasma mass spectrometer, which comprises a plurality of rod electrodes 201 arranged in a rotating structure around the longitudinal axis of a shell 10 to form a multipole ion guide 20. The rotating structure is adopted, thereby generating a certain torque on the ion beam entering the guide, so that the ion beam is rotated and compressed at a set angle while oscillating forward, so that the ions move in a spiral manner in the collision / reaction cell according to the rotation direction of the rod electrodes 201, thereby reducing mutual collisions between ions, suppressing the rapid decay of the kinetic energy of the ions to be measured, and greatly improving the ion transmission efficiency in the collision mode; in addition, since a rotating multipole ion guide is adopted, while providing the ions with axial initial kinetic energy, it will continue to provide rotational kinetic energy consistent with the rotation direction of the multipole ions, thereby improving the initial kinetic energy of the ions and greatly reducing the generation of zero kinetic energy ions.

[0076] 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.

[0077] 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 rotating collision reaction cell of 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 multipole ion guide disposed inside the housing along a longitudinal axis of the housing, the 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; The multipole ion guide comprises a plurality of slender rod electrodes, which are arranged in a rotating structure around the longitudinal axis of the shell to generate a certain torque on ions entering the multipole ion guide and make the ions rotate and compress while oscillating forward.

2. The reaction cell according to claim 1, characterized in that The plurality of rod electrodes are located at predetermined radial distances orthogonal to a longitudinal axis of the housing, the plurality of rod electrodes are circumferentially spaced apart from each other around the longitudinal axis, and define an inlet and an outlet of the multipole ion guide.

3. The reaction cell according to claim 2, characterized in that The field diameter at the entrance end of the multipole ion guide is larger than the field diameter at the exit end; or The field diameter at the inlet end of the multipole ion guide is smaller than the field diameter at the outlet end.

4. 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.

5. 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.

6. 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.

7. The reaction cell according to claim 1, characterized in that The rotation angle between the two ends of the rod electrode is θ, wherein 0°<θ<360°.

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.

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