Magnetoelectric coupling focusing ion transmission device
By using a magneto-electric coupling focusing ion transport device, the problem of radial divergence of the ion beam under high-density conditions in mass spectrometry analysis is solved by utilizing the synergistic effect of the axial magnetic field and the radio frequency electric field, thus achieving efficient ion transport and improving the sensitivity of the mass spectrometer.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2026-01-29
- Publication Date
- 2026-05-05
AI Technical Summary
During mass spectrometry analysis, the ion beam experiences severe radial divergence during transmission due to factors such as vacuum expansion, gas collisions, and charge repulsion. Existing devices, such as electrostatic lenses and radio frequency multipole rods, struggle to effectively suppress this divergence under high-density conditions, thus affecting detection sensitivity.
An ion transport device employing magneto-electric coupling focusing utilizes the synergistic effect of an axial magnetic field and a radio frequency electric field. The strong axial magnetic field generated by the guiding magnetic ring and the focusing magnetic ring, along with the radial electric field generated by the radio frequency multipole, work together to suppress the radial divergence of the ion beam.
It significantly improves ion transport efficiency and mass spectrometer detection sensitivity, reduces ion loss, and enhances ion utilization.
Smart Images
Figure CN121983500A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mass spectrometry analysis technology, and in particular to a magneto-electrically coupled focusing ion transport device. Background Technology
[0002] A mass spectrometer is an instrument that analyzes the composition and structure of substances by measuring the mass-to-charge ratio (m / z) of ions. It is currently widely used in fields such as biomedicine, environmental monitoring, and food safety. During mass spectrometry analysis, ions generated in the ionization source must pass through a transmission system before entering the mass analyzer. During this transmission stage, due to factors such as vacuum expansion, gas collisions, and charge repulsion, the ion beam undergoes severe radial divergence, resulting in a significant loss of ions and severely limiting detection sensitivity.
[0003] To improve ion transport efficiency, current technologies mainly employ devices such as electrostatic lenses and radio frequency multipole devices. Electrostatic lenses focus ions using an electrostatic field; their structure is relatively simple and power consumption is low, but their ability to suppress the strong space charge effect generated by high-density ion beams is limited. Radio frequency multipole devices (such as hexapoles or octopoles) are currently the mainstream ion guiding devices. They generate a dynamic focusing electric field by applying radio frequency voltages with opposite phases to adjacent rod electrodes, thereby restricting the radial movement of ions.
[0004] However, in certain specific application scenarios, such as the first-stage vacuum region following an atmospheric pressure ionization source, the vacuum expansion is extremely intense, and the initial ion beam density is extremely high. Under these conditions, even with a radio frequency multipole, the initial angular divergence of ions caused by strong expansion and space charge repulsion remains significant, making radial confinement by electric fields insufficient. Therefore, there is an urgent need in the field for a novel device that can more effectively suppress initial ion beam divergence, overcome strong space charge effects, and further improve ion transport efficiency. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a magneto-electrically coupled focusing ion transport device. This device is designed to strongly suppress radial divergence of the ion beam under high pressure differential and high density conditions through the synergistic effect of an axial magnetic field and a radio frequency electric field, achieving efficient transmission of the ion beam over a wide mass range, thereby improving the sensitivity and ion utilization of the mass spectrometer.
[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0007] This invention provides a magneto-electric coupling focusing ion transport device, including a front differential electrode, a circular vacuum cavity, a rear differential electrode, a radio frequency multipole, a guiding magnetic ring and a focusing magnetic ring. The circular vacuum cavity is a horizontally arranged cylindrical structure with openings at both ends. The front differential electrode and the rear differential electrode are both circular flat plate structures with a central hole, and are respectively sealed and insulated from the openings at both ends of the circular vacuum cavity.
[0008] The guide magnetic ring and the focusing magnetic ring are arranged axially in a circular vacuum cavity, with the guide magnetic ring positioned close to the front differential electrode; the radio frequency multipole includes at least four rod-shaped electrodes surrounding the outside of the focusing magnetic ring;
[0009] The guiding magnetic ring is used to generate a first axial magnetic field; the focusing magnetic ring is used to generate a second axial magnetic field, the magnetic field strength of the second axial magnetic field being greater than the magnetic field strength of the first axial magnetic field;
[0010] The focusing magnetic ring and the radio frequency multipole are at least partially overlapped in the axial direction, so that the second axial magnetic field and the radial focusing electric field generated by the radio frequency multipole overlap and couple in space.
[0011] A DC voltage is applied to each rod-shaped electrode in the front differential electrode, the rear differential electrode, and the radio frequency multipole.
[0012] The axes of the front differential electrode, the rear differential electrode, the radio frequency multipole, the guide magnetic ring, and the focusing magnetic ring are all collinear with the axis of the circular vacuum cavity, and the centers of all the rod-shaped electrodes in the radio frequency multipole are evenly distributed on the same circumference.
[0013] The radio frequency multipole is a quadrupole, hexapole, or octapole, wherein each rod electrode has the same structure, with a length of 90-200 mm and a diameter of 9-16 mm.
[0014] The front differential electrode has a thickness of 2-6 mm and a central hole diameter of 0.1-2 mm; the rear differential electrode has a thickness of 2-4 mm and a central hole diameter of 2-4 mm.
[0015] The front-end differential electrode, the rear-end differential electrode, and each rod-shaped electrode in the radio frequency multipole are made of conductive metal material or material with a conductive metal layer plated on the surface.
[0016] Both the guiding magnetic ring and the focusing magnetic ring are permanent magnet rings.
[0017] The thickness of the guiding magnetic ring is 15-40 mm, the inner diameter is 10-16 mm, and the strength of the first axial magnetic field generated is 0.01 T to 0.2 T; the thickness of the focusing magnetic ring is 15-40 mm, the inner diameter is 6-10 mm, and the strength of the second axial magnetic field generated is 0.05 T to 1 T.
[0018] The DC voltage applied to the front differential electrode is 100-400 V, the DC voltage applied to each rod electrode in the radio frequency multipole is 10-50 V, and the DC voltage applied to the rear differential electrode is 10-20 V. The DC voltage decreases sequentially along the ion transport direction.
[0019] Radio frequency voltage is also applied to each rod-shaped electrode in the radio frequency multipole.
[0020] The applied radio frequency on the radio frequency multipole is 0.5-5 MHz, and the radio frequency peak-to-peak value is 10-500 V. The radio frequency peak-to-peak values on the rod electrodes of any two adjacent radio frequency multipoles are equal in amplitude and opposite in phase.
[0021] The working pressure inside the circular vacuum cavity is maintained within the range of 10 Pa to 500 Pa.
[0022] The advantages and beneficial effects of this invention are: the introduction of the axial magnetic field in this invention provides a strong radial constraint force that cannot be achieved by an electric field, which can effectively suppress the space charge divergence of high-density ion beams and the large-angle scattering caused by violent vacuum expansion, thereby converging more ions and transmitting them to the downstream system, significantly reducing ion loss.
[0023] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.
[0024] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0025] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:
[0026] Figure 1 This is a schematic diagram of the structure of a magneto-electric coupling focusing ion transport device according to the present invention;
[0027] Figure 2 for Figure 1 Schematic diagram of the AA section.
[0028] In the diagram: 1. Front differential electrode; 2. Circular vacuum cavity; 3. Rear differential electrode; 4. RF multipole; 5. Guide magnetic ring; 6. Focusing magnetic ring. Detailed Implementation
[0029] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0030] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0031] See Figure 1 and Figure 2 As shown, the present invention provides a magneto-electric coupling focusing ion transport device, including a front differential electrode 1, a circular vacuum cavity 2, a rear differential electrode 3, a radio frequency multipole 4, a guiding magnetic ring 5, and a focusing magnetic ring 6. The circular vacuum cavity 2 is a cylindrical structure with horizontal arrangement and openings at both ends. The front differential electrode 1 and the rear differential electrode 3 are both circular flat plate structures with a central hole. The front opening of the circular vacuum cavity 2 is sealed and insulatedly connected to the front differential electrode 1, and the rear opening is sealed and insulatedly connected to the rear differential electrode 3. The guide magnetic ring 5 and the focusing magnetic ring 6 are axially disposed within the circular vacuum cavity 2, with the guide magnetic ring 5 positioned close to the front differential electrode 1. The radio frequency multipole 4 includes at least four rod-shaped electrodes surrounding the outside of the focusing magnetic ring 6, the four rod-shaped electrodes being parallel to the axis of the circular vacuum cavity 2. The guide magnetic ring 5 is used to generate a first axial magnetic field. The focusing magnetic ring 6 is used to generate a second axial magnetic field, the magnetic field strength of the second axial magnetic field being greater than that of the first axial magnetic field. The focusing magnetic ring 6 and the radio frequency multipole 4 are at least partially overlapped axially, such that the second axial magnetic field and the radial focusing electric field generated by the radio frequency multipole 4 are spatially overlapped and coupled. A DC voltage is applied to each rod-shaped electrode in the front differential electrode 1, the rear differential electrode 3, and the radio frequency multipole 4, and a radio frequency voltage is also applied to each rod-shaped electrode in the radio frequency multipole 4.
[0032] Furthermore, the axes of the front differential electrode 1, the rear differential electrode 3, the RF multipole 4, the guide magnetic ring 5, and the focusing magnetic ring 6 are all collinear with the axis of the circular vacuum cavity 2. The centers of all the rod-shaped electrodes in the RF multipole 4 are evenly distributed on the same circumference. (See [reference]). Figure 2 As shown
[0033] Specifically, the RF multipole 4 is a quadrupole, hexapole, or octapole, where each rod-shaped electrode has an identical structure, a length of 90-200 mm, and a diameter of 9-16 mm. The front differential electrode 1 has a thickness of 2-6 mm and a central hole diameter of 0.1-2 mm; the rear differential electrode 3 has a thickness of 2-4 mm and a central hole diameter of 2-4 mm. All rod-shaped electrodes in the front differential electrode 1, rear differential electrode 3, and RF multipole 4 are made of conductive metal materials (such as stainless steel) or materials with a conductive metal coating. The guiding magnetic ring 5 and the focusing magnetic ring 6 are both permanent magnet rings. The guiding magnetic ring 5 has a thickness of 15-40 mm and an inner diameter of 10-16 mm, generating a first axial magnetic field strength of 0.01 T to 0.2 T; the focusing magnetic ring 6 has a thickness of 15-40 mm and an inner diameter of 6-10 mm, generating a second axial magnetic field strength of 0.05 T to 1 T. The DC voltage applied to the front differential electrode 1 is 100-400 V, the DC voltage applied to each rod electrode in the RF multipole 4 is 10-50 V, and the DC voltage applied to the rear differential electrode 3 is 10-20 V, with the DC voltage decreasing sequentially along the ion transport direction. The RF frequency applied to the RF multipole 4 is 0.5-5 MHz, and the RF peak-to-peak value is 10-500 V. The RF peak-to-peak values on the rod electrodes of any two adjacent RF multipole 4 have equal amplitudes but opposite phases. The working pressure inside the circular vacuum chamber 2 is maintained within the range of 10 Pa to 500 Pa.
[0034] In a specific embodiment of the present invention, the radio frequency multipole 4 is a quadrupole, with each rod-shaped electrode having a length of 130 mm and a diameter of 12 mm; the front differential electrode 1 has a thickness of 3 mm and a central hole diameter of 0.5 mm; the rear differential electrode 3 has a thickness of 2 mm and a central hole diameter of 2 mm; all electrodes in the present invention are made of stainless steel. The guiding magnetic ring 5 and the focusing magnetic ring 6 are both neodymium iron boron permanent magnet rings. The guiding magnetic ring 5 has a thickness of 40 mm and an inner diameter of 10 mm, generating a first axial magnetic field strength of 0.1 T; the focusing magnetic ring 6 has a thickness of 40 mm and an inner diameter of 6 mm, generating a second axial magnetic field strength of 0.5 T. The DC voltage applied to the front differential electrode 1 is 100 V, the DC voltage applied to each rod electrode in the RF multipole 4 is 20 V, and the DC voltage applied to the rear differential electrode 3 is 18 V; the RF frequency applied to the RF multipole 4 is 2 MHz, and the RF peak-to-peak value is 400 V; the working pressure inside the circular vacuum chamber 2 is maintained at 400 Pa.
[0035] In an embodiment of the invention, the guiding magnetic ring 5 is located at the ion entry end, and the magnetic field it generates initially confines the ion beam, which diverges significantly after vacuum expansion. Subsequently, the ions enter the magneto-electric coupling focusing region formed by the focusing magnetic ring 6 and the radio frequency multipole 4. In this region, a strong axial magnetic field applies a Lorentz force to the ions, forcing them to perform cyclotronic motion, providing a strong radial confinement force that effectively counteracts divergence caused by space charge effects and initial kinetic energy dispersion. At the same time, the dynamic electric field generated by the radio frequency multipole 4 precisely focuses and axially guides the ions, ensuring that ions with different mass-to-charge ratios can be stably transported. The front differential electrode 1 and the rear differential electrode 3 are used to establish the required axial gradient electric field to assist in the introduction and extraction of ions.
[0036] This invention provides a magneto-electric coupled focusing ion transport device. A guiding magnetic ring and a focusing magnetic ring generate an axial magnetic field coaxial with the ion transport path, effectively constraining ion divergence caused by vacuum expansion and space charge effects. A radio frequency multipole is used to generate a radial dynamic focusing electric field for focusing and guiding ions. Through the synergistic coupling of the axial magnetic field and the radio frequency dynamic electric field, this invention achieves efficient transport of high-density ion beams across a wide mass range, thereby significantly improving the detection sensitivity and ion utilization of the mass spectrometer.
[0037] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A magneto-electric coupled focusing ion transport device, characterized in that, It includes a front differential electrode (1), a circular vacuum cavity (2), a rear differential electrode (3), a radio frequency multipole (4), a guide magnetic ring (5), and a focusing magnetic ring (6). The circular vacuum cavity (2) is a cylindrical structure with horizontal orientation and openings at both ends. The front differential electrode (1) and the rear differential electrode (3) are both circular flat plate structures with a central hole, and are respectively sealed and insulated from the openings at both ends of the circular vacuum cavity (2). The guide magnetic ring (5) and the focusing magnetic ring (6) are arranged axially in the circular vacuum cavity (2), and the guide magnetic ring (5) is arranged close to the front differential electrode (1); the radio frequency multipole (4) includes at least four rod-shaped electrodes surrounding the outside of the focusing magnetic ring (6); The guiding magnetic ring (5) is used to generate a first axial magnetic field; the focusing magnetic ring (6) is used to generate a second axial magnetic field, the magnetic field strength of the second axial magnetic field being greater than the magnetic field strength of the first axial magnetic field; The focusing magnetic ring (6) and the radio frequency multipole (4) are at least partially overlapped in the axial direction, so that the second axial magnetic field and the radial focusing electric field generated by the radio frequency multipole (4) overlap and couple in space; A DC voltage is applied to each rod-shaped electrode in the front differential electrode (1), the rear differential electrode (3), and the radio frequency multipole (4).
2. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The axes of the front differential electrode (1), the rear differential electrode (3), the radio frequency multipole (4), the guide magnetic ring (5) and the focusing magnetic ring (6) are all collinear with the axis of the circular vacuum cavity (2), and the centers of all the rod-shaped electrodes in the radio frequency multipole (4) are evenly distributed on the same circumference.
3. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The radio frequency multipole (4) is a quadrupole, hexapole, or octapole, wherein each rod electrode has the same structure, a length of 90-200 mm, and a diameter of 9-16 mm.
4. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The front differential electrode (1) has a thickness of 2-6 mm and a central hole diameter of 0.1-2 mm; the rear differential electrode (3) has a thickness of 2-4 mm and a central hole diameter of 2-4 mm. Each rod-shaped electrode in the front differential electrode (1), rear differential electrode (3) and radio frequency multipole (4) is made of conductive metal material or material with a conductive metal layer plated on its surface.
5. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, Both the guiding magnetic ring (5) and the focusing magnetic ring (6) are permanent magnet rings.
6. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The thickness of the guiding magnetic ring (5) is 15-40 mm, the inner diameter is 10-16 mm, and the strength of the first axial magnetic field generated is 0.01 T to 0.2 T; the thickness of the focusing magnetic ring (6) is 15-40 mm, the inner diameter is 6-10 mm, and the strength of the second axial magnetic field generated is 0.05 T to 1 T.
7. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The DC voltage applied to the front differential electrode (1) is 100-400 V, the DC voltage applied to each rod electrode in the radio frequency multipole (4) is 10-50 V, and the DC voltage applied to the rear differential electrode (3) is 10-20 V. The DC voltage decreases sequentially along the ion transport direction.
8. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, Radio frequency voltage is also applied to each rod electrode in the radio frequency multipole (4).
9. The magneto-electric coupled focusing ion transport device according to claim 8, characterized in that, The radio frequency applied to the radio frequency multipole (4) is 0.5-5 MHz, and the radio frequency peak value is 10-500 V. The radio frequency peak value amplitudes on the rod electrodes of any two adjacent radio frequency multipole (4) are equal and opposite in phase.
10. The magneto-electric coupled focusing ion transport device according to claim 1, characterized in that, The working pressure inside the circular vacuum cavity (2) is maintained in the range of 10 Pa to 500 Pa.