Ion reflector structure of time-of-flight mass spectrometer

Abstract

The invention discloses an ion reflector structure of a time-of-flight mass spectrometer, the ion reflector structure is a three-stage asymmetric electric field reflector structure and comprises a first-stage reflection electrode group, a second-stage reflection electrode group and a third-stage reflection electrode group, each group of electrodes at least comprises an electrode with asymmetric hole width, and the third-stage reflection electrode group comprises a second-stage reflection electrode group and a third-stage reflection electrode group. And all the electrodes are not provided with grid structures, are connected with a power supply system and can independently adjust the electrode voltage through the power supply system, so that high-order time focusing is realized. By independently adjusting the electrode voltage, ion path folding and high-order time focusing are realized, and the mass resolution and the sensitivity are remarkably improved. The structure effectively avoids the problems of ion loss and electric field leakage, and is suitable for high-resolution and low-detection-limit mass spectrometry.

Description

Technical Field

[0001] The present invention belongs to the field of time-of-flight mass spectrometers, and more particularly, relates to an ion mirror structure of a time-of-flight mass spectrometer. Background Art

[0002] Due to its advantages such as fast analysis speed, high resolution, and wide mass range, time-of-flight mass spectrometers have been widely used in many fields such as material analysis, biomedicine, and environmental monitoring. Among them, the ion mirror, as one of the key components of the mass analyzer, its structural design directly affects the mass resolution, detection limit, and stability of the instrument.

[0003] Traditional ion mirrors mostly adopt symmetric electrode arrangements and grid structures to achieve ion path folding and partial time focusing functions. However, the existing designs have the following obvious deficiencies:

[0004] (1) Limited resolution improvement: The symmetric structure limits the regulation space of the electric field distribution in design, making it difficult to achieve higher-order time focusing, thus restricting the further improvement of the mass spectrometer resolution.

[0005] (2) Limited sensitivity: To solve the electric field boundary effect and electric field leakage problems, traditional mirrors generally introduce metal grids, but the grids inevitably scatter ions, significantly reducing the ion transmission rate, and thus affecting the overall signal intensity, especially prominent in trace analysis.

[0006] (3) Inherent defects of the gridless design: Although the gridless mirror can avoid ion scattering problems, the electric field boundary effect is severe, resulting in ion orbit divergence, and a large number of ions are lost during flight, affecting the detection accuracy and repeatability. Summary of the Invention

[0007] The purpose of the present invention is to provide an ion mirror structure of a time-of-flight mass spectrometer to solve the above problems. For this purpose, the technical solution adopted by the present invention is as follows:

[0008] An ion mirror structure of a time-of-flight mass spectrometer, wherein the ion mirror structure is a three-stage asymmetric electric field mirror structure, including a first-stage reflection electrode group, a second-stage reflection electrode group, and a third-stage reflection electrode group. Each group of electrodes includes at least one electrode with an asymmetric hole width, and no grid structure is installed on all electrodes. Each electrode is connected to a power supply system and can independently adjust the electrode voltage through the power supply system to achieve higher-order time focusing.

[0009] In one embodiment, the first-stage reflection electrode group includes two electrodes with square through-holes, and the hole width of one electrode is smaller than that of the other, forming an asymmetric electric field distribution.

[0010] In one embodiment, the opening width of one of the electrodes is 1 / 5 to 1 / 3 of the opening width of the other electrode.

[0011] In one embodiment, the second-stage reflection electrode group includes three electrodes each having a square through-hole, wherein the opening width of one electrode is smaller than that of the other two electrodes to enhance the ion spatial focusing ability.

[0012] In one embodiment, the opening width of one electrode is 1 / 5 to 1 / 3 of the opening widths of the other two electrodes.

[0013] In one embodiment, the third-stage reflection electrode group includes an electrode having a square through-hole and a non-hole electrode to form an ion final reflection surface for controlling the ion reflection end point and the focusing behavior.

[0014] In one embodiment, each electrode is made of a stainless steel thin sheet.

[0015] The beneficial effects of the present invention adopting the above technical solutions are as follows.

[0016] 1) Significantly improve the resolution: The asymmetric three-stage structure combined with multi-stage voltage regulation can achieve high-order time focusing. Under the same design, the mass resolution can be improved by 20 - 50%.

[0017] 2) Improve the sensitivity and reduce the detection limit: The gridless design eliminates the ion scattering and adsorption effects, improves the ion transmission rate, and is suitable for the detection of trace components. Description of the Drawings

[0018] Figure 1 is a schematic XZ-direction cross-sectional view of the ion mirror structure of a time-of-flight mass spectrometer according to an embodiment of the present invention;

[0019] Figure 2 is a schematic YZ-direction cross-sectional view of the ion mirror structure of a time-of-flight mass spectrometer according to an embodiment of the present invention. Detailed Embodiments

[0020] The following will describe the preferred embodiments of the present invention in detail with reference to the drawings to more clearly understand the purpose, features, and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not limitations on the scope of the present invention, but only to illustrate the essential spirit of the technical solution of the present invention.

[0021] In the following description, for the purpose of illustrating the various disclosed embodiments, certain specific details are set forth to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other instances, well-known devices, structures, and techniques associated with the present application may not be shown or described in detail so as not to unnecessarily obscure the description of the embodiments.

[0022] Unless the context requires otherwise, throughout the specification and claims, the words "comprising" and its variations such as "comprises" and "having" shall be understood in an open, inclusive sense, i.e., shall be interpreted to mean "including, but not limited to".

[0023] References to "an embodiment" or "one embodiment" in the course of the specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in an embodiment" or "in one embodiment" in various places throughout the specification are not necessarily all referring to the same embodiment. Additionally, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0024] As used in this specification and the appended claims, the singular forms "a" and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally used in its inclusive sense of "and / or" unless the context clearly dictates otherwise.

[0025] In the following description, for the purpose of clearly showing the structure and working manner of the present invention, many directional terms will be used for description. However, terms such as "front", "rear", "left", "right", "outer", "inner", "outward", "inward", "up", "down", etc. should be understood as convenient terms and should not be construed as limiting terms.

[0026] Furthermore, terms such as "horizontal", "vertical", "hanging", etc. do not imply that the components are absolutely horizontal or hanging, but may be slightly inclined. For example, "horizontal" merely means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.

[0027] In the description of the present application, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0028] As Figure 1 and 2 shown, the ion mirror structure of a time-of-flight mass spectrometer according to an embodiment of the present invention is a three-stage asymmetric electric field mirror structure, which may include a first-stage reflection electrode group 1, a second-stage reflection electrode group 2, and a third-stage reflection electrode group 3 arranged from top to bottom. Each group of electrodes includes at least one electrode with an asymmetric hole width, effectively reducing the electric field edge leakage effect and achieving spatial beam convergence and energy compensation during the ion reflection process. No grid structure is installed on all electrodes, thus completely eliminating ion scattering losses. Each electrode is connected to a power supply system and the electrode voltage can be independently adjusted through the power supply system to form a multi-gradient electric field distribution, achieving high-order time focusing and significantly improving the mass resolution of the time-of-flight mass spectrometer. The structures of each group of electrodes are described in detail below.

[0029] The first-stage reflection electrode group 1 includes two stainless steel thin sheet electrodes. Each electrode is cut with two square through-holes for the ion beam to pass through. The opening width W in the Y direction of one of the electrodes is significantly smaller than that of the other, forming an asymmetric electric field distribution. Preferably, the opening width W in the Y direction of one electrode is 1 / 6 to 1 / 3 of the opening width W in the Y direction of the other electrode.

[0030] The second-stage reflection electrode group 2 includes three stainless steel thin sheet electrodes. Each electrode is cut with a square through-hole for the ion beam to pass through. The opening width W in the Y direction of one of the electrodes is significantly smaller than that of the other two, for further compressing the ion beam and achieving spatial focusing. Preferably, the opening width W in the Y direction of one electrode is 1 / 6 to 1 / 3 of the opening width W in the Y direction of the other two electrodes.

[0031] The third-stage reflection electrode group 3 includes a stainless steel thin sheet electrode with a square through-hole and a stainless steel thin sheet electrode without a hole, forming the final ion reflection surface for controlling the ion reflection end point and focusing behavior. Among them, the square through-hole in the third-stage reflection electrode group 3 is the same size as the square through-hole with a larger opening width W in the Y direction in the first-stage reflection electrode group 1 and the second-stage reflection electrode group 2.

[0032] In this embodiment, the first-stage reflection electrode group 1, the second-stage reflection electrode group 2, and the second-stage reflection electrode group 2 are all made of stainless steel thin sheets. It should be understood that each electrode can also be made of other metal materials.

[0033] The preferred embodiments of the present invention have been described in detail above. However, it should be understood that after reading the above teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention. These equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. An ion mirror structure of a time-of-flight mass spectrometer, characterized in that, The ion mirror structure is a three-stage asymmetric electric field mirror structure, including a first-stage reflection electrode group, a second-stage reflection electrode group, and a third-stage reflection electrode group. Each group of electrodes includes at least one electrode with an asymmetric hole width, and no grid structure is installed on all electrodes. Each electrode is connected to a power supply system and can independently adjust the electrode voltage through the power supply system to achieve high-order time focusing.

2. The ion mirror structure of the time-of-flight mass spectrometer according to claim 1, characterized in that, The first-stage reflection electrode group includes two electrodes with two square through-holes. The hole width of one electrode is smaller than that of the other, forming an asymmetric electric field distribution.

3. The ion mirror structure of the time-of-flight mass spectrometer according to claim 2, characterized in that, The hole width of one electrode is 1 / 5 to 1 / 3 of the hole width of the other electrode.

4. The ion mirror structure of the time-of-flight mass spectrometer according to claim 1, wherein The second-stage reflection electrode group includes three electrodes with square through-holes. Among them, the hole width of one electrode is smaller than that of the other two electrodes to enhance the ion spatial focusing ability.

5. The ion mirror structure of the time-of-flight mass spectrometer according to claim 4, characterized in that, The hole width of one electrode is 1 / 5 to 1 / 3 of the hole width of the other two electrodes.

6. The ion mirror structure of the time-of-flight mass spectrometer according to claim 1, characterized in that, The third-stage reflection electrode group includes one electrode with a square through-hole and one electrode without a hole, forming the final ion reflection surface for controlling the ion reflection end point and focusing behavior.

7. The ion mirror structure of the time-of-flight mass spectrometer according to any one of claims 1-6, characterized in that, Each electrode is made of a stainless steel sheet.

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