A multi-pole rod - quadrupole rod coupled collision cell

Abstract

The present invention discloses a multi-pole rod - quadrupole rod coupled collision cell, comprising: a multi-pole rod assembly and a quadrupole rod assembly; the diameter of the cross-section of the multi-pole rod assembly gradually decreases along the direction of ion transmission; the output end of the multi-pole rod assembly is connected to the input end of the quadrupole rod assembly; the multi-pole rod assembly and the quadrupole rod assembly are coaxially arranged. In summary, by providing an incident port with a wide inner diameter, the present invention can increase the incident range of ions, reduce the requirement for the ion beam width, and also improve the transmission efficiency and collision efficiency of ions within an appropriate range, thereby optimizing the sensitivity and accuracy of the mass spectrometry device.

Description

Technical Field

[0001] The present invention relates to the technical field of testing or analyzing materials by measuring the chemical or physical properties of the materials, and particularly relates to a multi-pole rod - quadrupole rod coupled collision cell. Background Art

[0002] In the prior art, it is a relatively common technical means to use a mass spectrometry device to measure the chemical or physical properties of a material for testing or analyzing the material. The main steps are to ionize the sample using an ion source, and then the charged ions enter the mass spectrometer, and the main part is the mass analyzer. The mass analyzer separates ions of different masses according to the mass-to-charge ratio (m / z) of the charged ions; the mass spectrometer detects and records the signal intensity of each mass of ions. These signal intensities are associated with the concentration of specific molecules in the sample and can be used for quantitative analysis.

[0003] In the field of mass spectrometry technology, common mass analyzers include Time-of-Flight Mass Spectrometer (TOF-MS), Quadrupole Mass Spectrometer (QMS), Ion Trap Mass Spectrometer, etc. Each instrument has its unique analysis characteristics and application scope. In a quadrupole mass spectrometer, the collision & reaction cell, as a bridge between mass analyzers, is one of the key components of the quadrupole mass spectrometry instrument, and its performance has an important impact on both the detection and the accuracy of mass spectrometry analysis. The collision & reaction cell is an important place to reduce the influence of interfering substances in quadrupole mass spectrometry technology. In the prior art, a quadrupole rod is mostly used as the collision & reaction cell structure. By applying a certain RF radio frequency voltage and a DC bias voltage on the quadrupole rod and making it operate in a low-vacuum environment filled with hydrogen or helium, hydrogen mainly removes interference through reactions, and helium can remove the influence of interfering substances such as multi-charged ions, polyatomic ions, and oxide ions through kinetic energy discrimination generated by simple mechanical collisions to obtain qualitative and quantitative information of the target ions.

[0004] However, the collision cell can only screen the ion energy by applying an electric field, which will result in a large number of target ions being screened out as well. Therefore, in the collision & reaction mode of a conventional quadrupole mass spectrometer, the sensitivity will drop significantly.

[0005] In the field of mass spectrometry, the sensitivity of a mass spectrometer is a key parameter, which is related to the lower detection limit of trace substances by the instrument. For a quadrupole mass spectrometer, the ion transmission performance of the collision cell plays a crucial role in the sensitivity of the whole instrument. Especially when analyzing complex matrices, we need to make a trade-off between the ion transmission efficiency in the collision cell and the removal effect of interfering substances.

[0006] The transmission mass range and efficiency of different types of transmission rods are different. Currently, common multipole collision cells have a larger mass range, but limited transmission efficiency. At the exit of the multipole, the distribution of the ion beam is also relatively divergent.

[0007] Although the quadrupole collision cell has a high transmission efficiency, the ion transmission efficiency for high and low mass segments is not high. In addition, the mass acceptance range of the quadrupole is relatively small, with a high requirement for the initial divergence of ions. Moreover, due to the relatively short ion movement path and small oscillation amplitude in the quadrupole structure, the collision probability between ions and the collision gas is limited, resulting in low collision efficiency, which affects the fragmentation effect of interfering substances and the accuracy of the analysis results.

[0008] The above-mentioned defects of the multipole and quadrupole directly affect the sensitivity of mass spectrometry, especially when detecting low-concentration and complex matrix samples, these disadvantages are more obvious. Summary of the Invention

[0009] The purpose of the present invention is to disclose a multipole-quadrupole coupled collision cell, which solves the problems of low transmission efficiency of existing multipoles or quadrupoles and high requirements for the initial divergence of ions.

[0010] To achieve the above purpose, the present invention adopts the following technical solutions:

[0011] A multipole-quadrupole coupled collision cell, comprising: a multipole component and a quadrupole component; the diameter of the cross-section of the multipole component gradually decreases along the direction of ion transmission; the output end of the multipole component is connected to the input end of the quadrupole component; the multipole component and the quadrupole component are coaxially arranged.

[0012] In one embodiment, the quadrupole component includes: four first electrode rods in the shape of flat plates, and the four first electrode rods cooperate with each other to form a square tubular structure, and any two adjacent first electrode rods are perpendicular to each other.

[0013] In one embodiment, the multipole component includes: four groups of electrode rod units, the widths of the four electrode rod units gradually decrease along the direction of ion transmission; the center lines of the four electrode rod units are respectively aligned with the center lines of the four first electrode rods one by one.

[0014] In one embodiment, the electrode rod unit includes: a second electrode rod, a third electrode rod, and a fourth electrode rod in the shape of a flat plate; the third electrode rod and the fourth electrode rod are respectively located on both sides of the second electrode rod; the width of the second electrode rod is smaller than the width of the first electrode rod; the four second electrode rods are aligned with the four first electrode rods one by one.

[0015] In one embodiment, the widths of the third electrode rod and the fourth electrode rod both gradually decrease along the direction of ion transmission.

[0016] In one embodiment, the included angle between the first electrode rod and the second electrode rod is 150° - 170°.

[0017] In one embodiment, it further includes: a radio frequency power supply for applying radio frequency signals to the electrode rods, and the radio frequency power supply is electrically connected to each first electrode rod, each second electrode rod, each third electrode rod, and each fourth electrode rod respectively.

[0018] In one embodiment, the phases of the radio frequency signals applied to any two adjacent first electrode rods differ by 180°.

[0019] In one embodiment, the phase of the radio frequency signal applied to the second electrode rod is the same as the phase of the radio frequency signal applied to the adjacent first electrode rod.

[0020] In one embodiment, the phase of the radio frequency signal applied to the third electrode rod differs by 180° from the phase of the radio frequency signal applied to the adjacent second electrode rod.

[0021] In one embodiment, the phase of the radio frequency signal applied to the fourth electrode rod differs by 180° from the phase of the radio frequency signal applied to the adjacent second electrode rod.

[0022] In one embodiment, at the connection of the multi - pole rod assembly and the quadrupole rod assembly, the inner diameter of the cross - section of the third electrode rod is smaller than the inner diameter of the cross - section of the first electrode rod.

[0023] In one embodiment, the difference between the inner diameter of the cross - section of the third electrode rod and the inner diameter of the cross - section of the first electrode rod is 5 mm.

[0024] In one embodiment, the distance between the plane where the first side surface of the first electrode rod is located and the plane where the second side surface of the adjacent first electrode rod is located is 2 mm.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention provides a multi-pole - quadrupole coupled collision cell, comprising: a multi-pole component and a quadrupole component; the diameter of the cross-section of the multi-pole component gradually decreases along the direction of ion transmission; the output end of the multi-pole component is connected to the input end of the quadrupole component; the multi-pole component and the quadrupole component are coaxially arranged. In summary, by providing an incident port with a wide inner diameter, the present invention can increase the incident range of ions, reduce the requirement for the ion beam width, and also improve the transmission efficiency and collision efficiency of ions within an appropriate range, thereby optimizing the sensitivity and accuracy of the mass spectrometry device. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 is a first perspective three-dimensional schematic diagram of a multi-pole - quadrupole coupled collision cell of the present invention;

[0028] Figure 2 is Figure 1 a front view in the arrow direction of

[0029] Figure 3 is a second perspective three-dimensional schematic diagram of a multi-pole - quadrupole coupled collision cell of the present invention;

[0030] Figure 4 is Figure 3 a front view in the arrow direction of

[0031] Figure 5 is a first perspective three-dimensional structural schematic diagram of the multi-pole component of the present application;

[0032] Figure 6 is a second perspective three-dimensional structural schematic diagram of the multi-pole component of the present application;

[0033] Figure 7 is a side view of a multi-pole - quadrupole coupled collision cell of the present application;

[0034] Figure 8 is an axial front view of the ion transmission path of Experimental Group 1 in Embodiment 3 of the present application;

[0035] Figure 9 is a side view of the ion transmission path of Experimental Group 1 in Embodiment 3 of the present application;

[0036] Figure 10It is a schematic diagram of the ion transport path of Experimental Group 2 in Embodiment 3 of the present application;

[0037] Figure 11 It is the axial front view of the ion transport path of Experimental Group 3 in Embodiment 3 of the present application;

[0038] Figure 12 It is the side view of the ion transport path of Experimental Group 3 in Embodiment 3 of the present application;

[0039] Figure 13 It is a schematic diagram of the ion transport path of Experimental Group 4 in Embodiment 3 of the present application;

[0040] In the figure, 1 is the multi-pole rod assembly; 10 is the electrode rod unit; 101 is the second electrode rod; 102 is the third electrode rod; 104 is the fourth electrode rod; 105 is the tip; 2 is the quadrupole rod assembly; 201 is the first electrode rod. Detailed implementation manners

[0041] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and the like 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 directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0042] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "above" and "on the top" of the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below" and "under the bottom" of the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature. Terms such as "vertical", "horizontal", "left", "right", "up", "down" and similar expressions are only for the purpose of illustration, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0043] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0044] Embodiment 1

[0045] As Figure 1-7 shown, a multi-pole rod - quadrupole rod coupled collision cell includes: a multi-pole rod assembly 1 and a quadrupole rod assembly 2; the diameter of the cross-section of the multi-pole rod assembly 1 gradually decreases along the direction of ion transmission; the output end of the multi-pole rod assembly 1 is connected to the input end of the quadrupole rod assembly 2; the multi-pole rod assembly 1 and the quadrupole rod assembly 2 are coaxially arranged.

[0046] In the field of traditional mass spectrometry technology, in a quadrupole mass spectrometer, the collision reaction cell, as a bridge between mass analyzers, is one of the key components of a quadrupole mass spectrometer, and its performance has an important impact on both the detection and the accuracy of mass spectrometry analysis. Among them, the quadrupole is usually suitable for a relatively wide mass range, but may be limited in high-resolution analysis. Multi-pole rods, especially higher-order multi-pole rods, can provide higher mass resolution and are suitable for applications that require high-resolution analysis. However, in actual use, due to the small inner diameter of the quadrupole rod, the requirements for the beam width of the ion beam input to the quadrupole rod are relatively high. At the same time, when only using the quadrupole rod, the alternating electric field generated by its radio frequency signal is difficult to drive the ions to vibrate, and the collision probability between the ions and the collision gas is limited, resulting in low collision efficiency, thus affecting the fragmentation effect of interfering substances and the accuracy of the analysis results. To solve the above problems, the present application proposes a multi-pole rod - quadrupole rod coupled collision cell, wherein the inner diameter of the multi-pole rod gradually decreases along the direction of ion transmission. As Figure 1 shown, the opening at the input end of the multi-pole rod is in a flared state, and the inner diameter of the output end of the multi-pole rod is similar to that of the opening of the quadrupole rod. By using a multi-pole rod with such a flared shape, the requirements for the beam width of the ions can be reduced, and by applying a radio frequency voltage to the multi-pole rod, the ions injected into the multi-pole rod can gradually approach the axis of the multi-pole rod under the drive of the electric field of the multi-pole rod, realizing the focusing effect of the ion beam. In addition, since the inner diameter at the starting position of the multi-pole rod is large and the driving ability of the electric field on the electrode rod for the ions is weak, the movement path of the ions is longer. The longer movement path can increase the collision probability between the ions and the collision gas. The fragment ions generated by the collision can make the mass spectrometry peaks more detailed, enhancing the resolution. And since the fragment ions are usually relatively stable and have a clear mass-to-charge ratio, their detection signals are more significant relative to the noise, thereby improving the signal-to-noise ratio.

[0047] In one embodiment, the quadrupole rod assembly 2 includes: four first electrode rods 201 in a flat plate shape, and the four first electrode rods 201 cooperate with each other to form a square tubular structure, and any two adjacent first electrode rods 201 are perpendicular to each other.

[0048] In the present application, the quadrupole is formed by enclosing four flat first electrode rods 201. The four flat first electrode rods 201 form a square tube. There are certain gaps at the four corners of the square tube to facilitate the entry of collision gas into the quadrupole to collide with ions. The electric field distribution of the flat quadrupole is more uniform. Compared with the traditional cylindrical quadrupole, it can more effectively reduce the non-linear effect. In the flat quadrupole, the movement of ions is more stable and predictable, which is beneficial to improving the resolution and accuracy of the mass spectrometer. Due to the more uniform electric field distribution of the flat quadrupole, the transmission efficiency of ions in the quadrupole is higher. This can reduce the loss of ions during transmission and improve the intensity and stability of the signal. The flat quadrupole is also convenient for manufacturing and maintenance, and can effectively reduce the cost of the quadrupole.

[0049] In one embodiment, the multipole rod assembly 1 includes: four groups of electrode rod units 10. The widths of the four electrode rod units 10 gradually decrease along the direction of ion transmission. The center lines of the four electrode rod units 10 are respectively aligned with the center lines of the four first electrode rods 201 one by one.

[0050] In practical applications, the multipole rod is also composed of four groups of electrode rod units 10. The four groups of electrode rod units 10 can be aligned with the four first electrode rods 201 in the quadrupole one by one, so that the electric field of the multipole rod and the electric field of the quadrupole can be stably connected, improving the stability of ions passing between the two components.

[0051] In one embodiment, the electrode rod unit 10 includes: a flat second electrode rod 101, a third electrode rod 102, and a fourth electrode rod 104. The third electrode rod 102 and the fourth electrode rod 104 are respectively located on both sides of the second electrode rod 101. The width of the second electrode rod 101 is smaller than the width of the first electrode rod 201. The four second electrode rods 101 are aligned with the four first electrode rods 201 one by one.

[0052] In the present application, the number of the second electrode rods 101 is four. The second electrode rods 101 are also flat and are arranged obliquely outward along the axis. The width of the second electrode rod 101 is smaller than the width of the first electrode rod 201, which is convenient for destroying the electric field at the connection of the two components.

[0053] In one embodiment, the widths of the third electrode rod 102 and the fourth electrode rod 104 both gradually decrease along the direction of ion transmission.

[0054] In the present application, in order to gradually reduce the inner diameter of the multipole rod assembly 1, it is necessary to design the widths of the third electrode rod 102 and the fourth electrode rod 104 to be gradually decreasing structures, so that the electric field generated by the electrode rods can cover the inside of the multipole rod assembly 1, avoiding insufficient electric field coverage from affecting the force on the ions therein.

[0055] In one embodiment, the included angle θ between the first electrode rod 201 and the second electrode rod 101 is 150° to 170°.

[0056] As Figure X shown, the included angle θ between the first electrode rod 201 and the second electrode rod 101 is 150° to 170°. Such an angle can enable the electric fields of the multipole rod assembly 1 and the quadrupole rod assembly 2 to be smoothly connected to each other, facilitating the ions in the multipole rod system to smoothly pass through the connection and enter the quadrupole rod assembly 2.

[0057] In one embodiment, it further includes: a radio frequency power supply for applying a radio frequency signal to the electrode rods, and the radio frequency power supply is electrically connected to each first electrode rod 201, each second electrode rod 101, each third electrode rod 102, and each fourth electrode rod 104 respectively.

[0058] In actual use, the radio frequency power supply is used to generate a continuously alternating radio frequency signal. Applying the radio frequency signal to the electrode rods can cause the electrode rods to generate an electric field, and the electric field can cause the ions inside the multipole rod assembly 1 or the quadrupole rod assembly 2 to be deflected by the force. Since the radio frequency signal is constantly changing, the direction of the force on the ions is also constantly changing, and the ions will show an oscillating forward path. In the present application, the radio frequency power supply is not shown in the figure. The radio frequency power supply can adopt the scheme in the prior art, as long as it can be electrically connected to the electrode rods and apply a radio frequency signal to the electrode rods. In the present application, the voltage value of the radio frequency signal set on the multipole rod assembly is ; the frequency of the radio frequency signal is between . The voltage value of the radio frequency signal set on the quadrupole rod assembly is ; the frequency of the radio frequency signal is between , and a direct current of -10V to 10V is superimposed on the quadrupole rod assembly as a gradient electric field to attract ions into the quadrupole rod. Among them, using a direct current electric field as the gradient electric field, the purpose is to provide initial kinetic energy for the ions when the initial kinetic energy of the ions is small, so as to ensure that the ions can be transmitted backward. If the kinetic energy of the ions already meets the requirements, there is no need to superimpose a direct current electric field

[0059] In one embodiment, the phases of the radio frequency signals applied to any two adjacent first electrode rods 201 differ by 180°.

[0060] In actual use, as Figure 2 ,Figure 4 As shown, the radio frequency signal specifically uses a sine signal. The phases of the radio frequency signals on two opposite electrode rods in the quadrupole assembly 2 are the same, and the phases of the radio frequency signals on two adjacent electrode rods are opposite. Only in this way can the ions be kept oscillating and advancing inside the quadrupole.

[0061] In one embodiment, the phase of the radio frequency signal applied to the second electrode rod 101 is the same as the phase of the radio frequency signal applied to the adjacent first electrode rod 201.

[0062] The phase of the radio frequency signal applied to the second electrode rod 101 being the same as the phase of the radio frequency signal on the adjacent first electrode rod 201 can ensure the continuity of the electric field and avoid the influence of sudden changes in the electric field on ion transmission.

[0063] In one embodiment, the phase of the radio frequency signal applied to the third electrode rod 102 differs from the phase of the radio frequency signal applied to the adjacent second electrode rod 101 by 180°.

[0064] In one embodiment, the phase of the radio frequency signal applied to the fourth electrode rod 104 differs from the phase of the radio frequency signal applied to the adjacent second electrode rod 101 by 180°.

[0065] When ions pass through adjacent electrode rods, a phase difference of 180° can enable the ions to maintain a relatively stable orbit within the entire multipole system. This stability is crucial for maintaining the resolution and sensitivity of the mass spectrometer because the accurate separation of ions depends on their stable transmission in the multipole.

[0066] In one embodiment, at the connection between the multipole assembly 1 and the quadrupole assembly 2, the inner cross-sectional diameter of the third electrode rod 102 is smaller than the inner cross-sectional diameter of the first electrode rod 201.

[0067] In this application, such as Figure 5 、 Figure 6As shown, the widths of the third electrode rod 102 and the fourth electrode rod 104 are both in a gradually narrowing shape, and a tip 105 is provided at the end of the third electrode rod 102 and the end of the fourth electrode rod 104. The diameter of the inscribed circle formed by the multiple tips 105 is smaller than the diameter of the inner sidewall of the first electrode rod 201. If the ends of the third electrode rod 102 and the fourth electrode rod 104 are not narrowed inward so that the diameter of the inscribed circle of the third electrode rod 102 and the fourth electrode rod 104 is smaller than the diameter of the quadrupole rod, four small approximate quadrupole fields will be formed between the gaps of the quadrupole rod and the inserted rods, resulting in ions escaping from the original confinement range at these four corners. Therefore, by reducing the inner diameter between the third electrode rod 102 and the fourth electrode rod 104 to be smaller than the inner diameter at the quadrupole rod, the quadrupole electric field between the third electrode rod 102, the fourth electrode rod 104, and the two adjacent first electrode rods 201 can be destroyed, avoiding ion loss.

[0068] In one embodiment, the difference between the cross-sectional inner diameter R1 of the third electrode rod 102 and the cross-sectional inner diameter R2 of the first electrode rod 201 is . As Figure 4 shown, in the present application, the inner diameter R1 of the third electrode rod 102 is calculated based on the distance between the tip 105 of the third electrode rod 102 and the axis, and the cross-sectional inner diameter R2 of the first electrode rod 201 is calculated based on the distance between the edge inside the first electrode rod 201 and the axis. Inserting the third electrode rod 102 and the fourth electrode rod 104 into the gap between two adjacent first electrode rods 201 can destroy the small approximate quadrupole field formed in the gap and also prevent ions from escaping from the gap.

[0069] In one embodiment, the distance between the plane where the first side surface of the first electrode rod 201 is located and the plane where the second side surface of the adjacent first electrode rod 201 is located is .

[0070] In the present application, the first side surface is a side surface of the first electrode rod 201 facing the axis, that is, the plane inside the first electrode rod 201; the second side surface of the quadrupole rod is a side surface parallel to the first side surface and closest to the first side surface. As Figure 4 shown, that is, the distance in this figure .

[0071] In summary, the present application proposes a multi-pole - quadrupole coupled collision cell system. By setting a multi-pole collision cell with a flared structure, the requirement for the beam width of the incident ions can be reduced, the movement distance of the ions inside the multi-pole can be extended, and the collision efficiency between the ions and the collision gas can be improved. Then, a quadrupole is connected behind the multi-pole, which can prevent the ion beam focused by the multi-pole from diverging again, but make it more stable under the action of the quadrupole, thereby ensuring that more ions can enter the mass spectrometer.

[0072] Example Two

[0073] Furthermore, the present application also provides a calculation method for the RF voltage value of this device, specifically including:

[0074]

[0075] Wherein, represents the ion mass, represents the angular frequency of the applied electric field, represents the effective field radius, represents the electronic charge (constant), and are artificially defined dimensionless numbers, generally taking 0.908, which is the boundary of the stable region.

[0076] In the present application, both the multi-pole and the quadrupole use the above equation to determine the voltage.

[0077] Example Three

[0078] Furthermore, the present application also provides an ion transmission simulation experiment to demonstrate the advantages of the structure of the present application, specifically including the following four groups of experiments:

[0079] Experimental Group 1: The collision cell structure adopts the multi-pole - quadrupole coupled collision cell system described in Example One, and the diameter of the incident ion beam is ; the voltage of the RF signal applied to the multi-pole component and the quadrupole component is , the frequency of the RF signal is: , and a DC voltage is superimposed on the quadrupole as a gradient electric field. The ion transmission trajectory of Experimental Group 1 is as shown in Figure 8 , Figure 9 .

[0080] Experimental Group 2: The collision cell structure only adopts the quadrupole collision cell system, and the diameter of the incident ion beam is ; the voltage of the RF signal applied to the quadrupole component is , the frequency of the RF signal is: , and the ion transmission trajectory of Experimental Group 2 is as shown in Figure 10 .

[0081] In the figure, the square part represents the structure of the device, and the internal hatching represents the movement trajectory of ions; it can be seen from the figure that compared with Experimental Group 2, the beam width of the ion beam in Experimental Group 1 is more compact, the number of ion oscillations is more, and the movement path is longer.

[0082] Experimental Group 3: The collision cell structure adopts the multipole - quadrupole coupled collision cell system described in Example 1, and the diameter of the incident ion beam is ; the voltage of the radio frequency signal applied to the multipole component and the quadrupole component is , and the frequency of the radio frequency signal is: , and a DC voltage is superimposed on the quadrupole as a gradient electric field. The ion transmission trajectory of Experimental Group 1 is as shown in Figure 11 、 Figure 12 .

[0083] Experimental Group 2: The collision cell structure only adopts the quadrupole collision cell system, and the diameter of the incident ion beam is ; the voltage of the radio frequency signal applied to the quadrupole component is , and the frequency of the radio frequency signal is: , and the ion transmission trajectory of Experimental Group 2 is as shown in Figure 13 .

[0084] It can be seen from the figure that compared with Experimental Group 4, the beam width of the ion beam in Experimental Group 3 is more compact, the number of ion oscillations is more, the movement path is longer, and the ion loss rate is lower, having a good focusing effect.

[0085] The present invention is not limited to the above - mentioned embodiments. If various modifications or variations of the present invention do not depart from the spirit and scope of the present invention, and provided that these modifications and variations are within the scope of the claims of the present invention and equivalent technical scope, then the present invention also intends to include these modifications and variations.

Claims

1. A multi-pole rod - quadrupole rod coupled collision cell, characterized in that, Comprising: A multi-pole rod assembly (1) and a quadrupole rod assembly (2); a split structure is provided between the multi-pole rod assembly (1) and the quadrupole rod assembly (2); the diameter of the cross-section of the multi-pole rod assembly (1) gradually decreases along the direction of ion transmission; The output end of the multi-pole rod assembly (1) is connected to the input end of the quadrupole rod assembly (2); the multi-pole rod assembly (1) and the quadrupole rod assembly (2) are coaxially arranged; The quadrupole rod assembly (2) includes: four first electrode rods (201) in the shape of flat plates, and the four first electrode rods (201) cooperate with each other to form a square tubular structure, and any two adjacent first electrode rods (201) are perpendicular to each other; The multi-pole rod assembly (1) includes: four groups of electrode rod units (10), and the widths of the four electrode rod units (10) gradually decrease along the direction of ion transmission; the center lines of the four electrode rod units (10) are respectively aligned with the center lines of the four first electrode rods (201) one by one; The electrode rod unit (10) includes: a second electrode rod (101), a third electrode rod (102), and a fourth electrode rod (104) in the shape of flat plates; The third electrode rod (102) and the fourth electrode rod (104) are respectively located on both sides of the second electrode rod (101); the width of the second electrode rod (101) is smaller than the width of the first electrode rod (201); The four second electrode rods (101) are aligned with the four first electrode rods (201) one by one; At the connection between the multi-pole rod assembly (1) and the quadrupole rod assembly (2), a tip (105) is provided at the end of each of the third electrode rod (102) and the fourth electrode rod (104), and the diameter R1 of the inscribed circle formed by the multiple tips (105) is smaller than the diameter R2 of the inner side wall of the first electrode rod (201).

2. A multipole - quadrupole coupled collision cell according to claim 1, characterized in that, The widths of both the third electrode rod (102) and the fourth electrode rod (104) gradually decrease along the direction of ion transmission.

3. The multi-pole rod - quadrupole rod coupled collision cell according to claim 2, wherein The included angle between the first electrode rod (201) and the second electrode rod (101) is 150° - 170°.

4. The multipole - quadrupole coupled collision cell according to claim 3, wherein Further comprising: A radio frequency power supply for applying a radio frequency signal to the electrode rods, and the radio frequency power supply is electrically connected to each of the first electrode rods (201), each of the second electrode rods (101), each of the third electrode rods (102), and each of the fourth electrode rods (104).

5. A multipole - quadrupole coupled collision cell according to claim 4, wherein The phases of the radio frequency signals applied to any two adjacent first electrode rods (201) differ by 180°.

6. The multi-pole rod - quadrupole rod coupled collision cell according to claim 5, wherein, The phase of the radio frequency signal applied to the second electrode rod (101) is the same as the phase of the radio frequency signal applied to the adjacent first electrode rod (201); the phase of the radio frequency signal applied to the third electrode rod (102) differs by 180° from the phase of the radio frequency signal applied to the adjacent second electrode rod (101); the phase of the radio frequency signal applied to the fourth electrode rod (104) differs by 180° from the phase of the radio frequency signal applied to the adjacent second electrode rod (101).

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