A MEMS mass spectrometry chip and a mass spectrometry analysis method

Abstract

The application belongs to the field of miniaturized mass spectrometry technology, and provides a MEMS mass spectrometry chip and a mass spectrometry analysis method, wherein the mass spectrometry chip comprises an ion optical path unit and a vacuum unit; the vacuum unit surrounds the ion optical path unit, and an ion flight space is formed inside; the ion flight space is used for providing a flight path for ions transmitted in the ion optical path unit; along the flight path, the ion optical path unit is integrated with an ion source, a focusing lens, a mass analyzer and an ion detector arranged in sequence. The mass spectrometry chip integrates the ion optical path unit and the vacuum unit, and when working, can sequentially complete a complete mass spectrometry analysis process of ion generation, ion beam focusing correction, ion mass screening and ion signal detection, has high structural integration degree, is small in size, can effectively improve the gas analysis precision and working stability of the MEMS mass spectrometry chip, and provides a solution for a chip-level mass spectrometry system.

Description

Technical Field

[0001] This invention belongs to the field of miniaturized mass spectrometry technology, and specifically relates to a MEMS mass spectrometry chip and a mass spectrometry analysis method. Background Technology

[0002] Mass spectrometry, based on the intrinsic mass properties of substances' ions, acquires information about the composition of substances and is a core technology and universal method in the field of analysis. It mainly consists of two parts: an ion optical path system comprising an ion source, an ion focusing lens, a mass analyzer, and an ion detector, and a vacuum system comprising a vacuum chamber, a vacuum pump, and a vacuum gauge.

[0003] MEMS mass spectrometry, which deeply integrates micro-electro-mechanical systems (MEMS) manufacturing processes with mass spectrometry technology, has become a crucial technological direction driving the miniaturization of mass spectrometers due to its significant advantages such as high integration, ultra-low power consumption, small size and lightweight design, and mass production capabilities. Currently, significant progress has been made in the MEMS-based research of key mass spectrometry functional devices, such as MEMS ion sources, MEMS mass analyzers, and MEMS detectors. However, existing work mainly focuses on the design and fabrication of single-function devices, lacking integrated solutions for the overall functionality of MEMS mass spectrometry systems, and has yet to develop chip-level mass spectrometry systems with autonomous operation capabilities. Summary of the Invention

[0004] To address the problems in the background art, this invention proposes a MEMS mass spectrometry chip and a mass spectrometry analysis method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A MEMS mass spectrometry chip, comprising an ion optical path unit and a vacuum unit; The vacuum unit surrounds the ion optical path unit, and the interior forms the ion flight space; the flight space is used to provide a flight path for the ions transported within the ion optical path unit; Along the flight path, the ion optical path unit integrates an ion source, a focusing lens, a mass analyzer, and an ion detector arranged in sequence.

[0006] Furthermore, the focusing lens includes an upper electrode and a lower electrode; the upper electrode and the lower electrode are symmetrically arranged with the flight space as the center.

[0007] Furthermore, the mass analyzer includes an upper analytical electrode and a lower analytical electrode; the upper analytical electrode and the lower analytical electrode are symmetrically arranged with the flight space as the center.

[0008] Furthermore, the ion detector includes an upper detection electrode and a lower detection electrode; The upper and lower detection electrodes are symmetrically arranged with the flight space as the center.

[0009] Furthermore, the vacuum unit includes a vacuum-sealed chamber, a getter pump, and an ion pump; An ion optical path unit is installed inside the vacuum-sealed chamber, and a sample introduction microchannel is opened at one end. The sample introduction microchannel is used to deliver the gas to be tested to the ion source inside the vacuum-sealed chamber. The getter pump is located inside the vacuum-sealed chamber and is distributed around the mass analyzer. The ion pump is located inside the vacuum-sealed chamber, at the end of the ion detector away from the mass analyzer.

[0010] Furthermore, the vacuum-sealed chamber includes a first substrate, a second substrate, and a third substrate stacked sequentially; The second substrate has a hollow structure, forming a space for ion flight; The opposing surfaces of the first and third substrates are used to mount a focusing lens, a mass analyzer, an ion detector, a getter pump, and an ion pump.

[0011] Furthermore, the ion pump includes an upper electrode plate, a lower electrode plate, and a filament; The upper electrode plate is mounted on the surface of the first substrate facing the third substrate, and the lower electrode plate is mounted on the surface of the third substrate facing the first substrate. The upper and lower electrode plates are symmetrically arranged with the flight space as the center; the filament is mounted on the surface of the lower electrode plate.

[0012] Furthermore, the ion source is a field emission ion source, an on-chip photoelectric effect ion source, or an on-chip electron bombardment ion source.

[0013] Furthermore, the mass analyzer can be an on-chip ion trap mass analyzer, a coplanar linear ion trap mass analyzer, or a MEMS cycloidal mass analyzer.

[0014] A mass spectrometry analysis method, executed using a MEMS mass spectrometry chip as described above, includes the following steps: The ion source ionizes the gas to be tested to form charged ions; The focusing lens focuses the charged ion beam and transmits the charged ions to the mass analyzer; Mass analyzers separate ions based on their different mass-to-charge ratios. The ion detector receives the separated charged ions and completes ion detection.

[0015] The beneficial effects of this invention are: The mass spectrometry chip of this invention integrates an ion optical path unit and a vacuum unit. During operation, it can sequentially complete the entire mass spectrometry analysis process of ion generation, ion beam focusing correction, ion mass screening, and ion signal detection. It has a high degree of structural integration and a small size, which can effectively improve the gas analysis accuracy and working stability of MEMS mass spectrometry chips. This invention proposes a solution for chip-level mass spectrometry systems.

[0016] 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 pointed out in the description and the drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of a MEMS mass spectrometry chip according to the present invention is shown; Figure 2 A schematic diagram of the internal structure of the MEMS mass spectrometry chip of the present invention is shown; Figure 3 The ion flight path diagram of the present invention is shown; Figure 4 A schematic diagram of the structure of the vacuum sealing chamber of the present invention is shown; Figure 5 A flowchart of a mass spectrometry analysis method according to the present invention is shown.

[0019] In the diagram: 1. Ion optical path unit; 11. Ion source; 12. Focusing lens; 1201. Upper electrode of the lens; 1202. Lower electrode of the lens; 13. Mass analyzer; 1301. Upper analytical electrode; 1302. Lower analytical electrode; 14. Ion detector; 1401. Upper detection electrode; 1402. Lower detection electrode; 2. Vacuum unit; 21. Sample introduction microchannel; 22. Vacuum sealing chamber; 221. First substrate; 222. Second substrate; 223. Third substrate; 23. Getter pump; 24. Ion pump; 2401. Upper electrode plate; 2402. Lower electrode plate; 2403. Filament; 3. Flight space. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1The image shows a MEMS mass spectrometry chip, consisting of an ion optical path unit 1 for gas analysis and a vacuum unit 2 for maintaining a vacuum state. The vacuum unit 2 surrounds the ion optical path unit 1 and forms an ion flight space 3 inside, which provides a flight path for the ions transported within the ion optical path unit 1.

[0022] Along the flight path, the ion optical path unit 1 integrates an ion source 11, a focusing lens 12, a mass analyzer 13, and an ion detector 14 arranged sequentially. For example... Figure 3 As shown, during operation, after the vacuum level inside the vacuum unit 2 reaches the gas analysis conditions, sample injection analysis begins. At this time, the target detection gas a enters the vacuum sealed chamber 22 and is ionized into a charged ion beam b under the action of the ion source 11. The charged ion beam b is focused by the ion focusing lens 12 and enters the mass analyzer 13. c is the trajectory of the charged ion beam b. Under the action of the mass analyzer 13, the ions are separated and released in sequence according to the different mass-to-charge ratios. The separated ions are captured by the ion detector 14 and form a current signal with a reaction signal intensity.

[0023] It should be noted that the integrated design of the above-mentioned functional structures can sequentially complete the entire mass spectrometry analysis process, including ion generation, ion beam focusing correction, ion quality screening, and ion signal detection. The structure has a high degree of integration and a small size, which can effectively improve the gas analysis accuracy and working stability of MEMS mass spectrometry chips.

[0024] like Figure 2 As shown, in this embodiment, the focusing lens 12 adopts an electrode structure design with electrodes facing each other, specifically including an upper electrode 1201 and a lower electrode 1202. The upper electrode 1201 and the lower electrode 1202 are symmetrically arranged with the flight space 3 as the center. This symmetrical electrode structure can form a uniform and symmetrical electrostatic focusing electric field within the flight space 3. When the ion beam passes through the region of the focusing lens 12, it can achieve precise focusing and correction of the ion flight trajectory under the action of the electric field, effectively improving the ion beam divergence problem, significantly reducing trajectory deviation and loss during ion flight, and ensuring the regularity and transmission concentration of the ion beam.

[0025] Correspondingly, the mass analyzer 13 in this embodiment also adopts a symmetrical electrode arrangement structure, including an upper analytical electrode 1301 and a lower analytical electrode 1302, which are symmetrically arranged with the flight space 3 as the center. This symmetrical structure can create a uniform and stable analytical electric field in the region of the mass analyzer 13, so that ions with different mass-to-charge ratios can be deflected and separated according to the preset electric field law, avoiding the problems of electric field distortion and uneven force caused by unilateral electrode arrangement.

[0026] Furthermore, the ion detector 14 is equipped with an upper detection electrode 1401 and a lower detection electrode 1402, which are also symmetrically arranged around the flight space 3. This symmetrical detection electrode structure can capture the filtered ion signals omnidirectionally and symmetrically, effectively expanding the ion receiving range and avoiding the signal receiving blind spots and signal loss problems existing in unilateral detection, thus significantly improving the ion signal acquisition efficiency and detection sensitivity of the ion detector 14.

[0027] Furthermore, the vacuum unit 2 of the present invention specifically includes a vacuum sealing chamber 22, a getter pump 23, and an ion pump 24. The vacuum sealing chamber 22, as a sealed cavity structure, integrates the aforementioned ion optical path unit 1, and an injection microchannel 21 is provided at its end. The injection microchannel 21 enables the introduction of the analyte gas, stably delivering the external analyte gas to the ion source 11 inside the vacuum sealing chamber 22, providing a analyte gas sample for subsequent ionization analysis.

[0028] Both the getter pump 23 and the ion pump 24 are built into the vacuum-sealed chamber 22, achieving integrated installation. The getter pump 23 is positioned around the mass analyzer 13, specifically adsorbing and purifying impurities in the surrounding gas, quickly stabilizing the vacuum level in the mass analysis area, avoiding interference from residual gas on ion separation and screening, and ensuring the working accuracy of the mass analyzer 13. The ion pump 24 is positioned at the end of the ion detector 14 furthest from the mass analyzer 13, continuously extracting residual gas at the end of the chamber, further optimizing the vacuum environment of the flight space 3, reducing gas collision losses at the ion flight end, and preventing residual gas from interfering with ion signal acquisition, effectively improving the detection stability and accuracy of the ion detector 14.

[0029] like Figure 4 As shown, in this embodiment, the vacuum sealing chamber 22 adopts a multi-layer substrate stacked integrated structure, specifically including a first substrate 221, a second substrate 222, and a third substrate 223 stacked sequentially from top to bottom. The second substrate 222 is configured as a hollow through-structure, and the hollow area of ​​the second substrate 222 constitutes the flight space 3 of this invention, providing a sealed channel for the transmission, deflection, and movement of ions within the ion optical path unit 1. The first substrate 221 and the third substrate 223 are arranged vertically opposite each other, and their facing inner surfaces can serve as integrated mounting bases for uniformly assembling and fixing the focusing lens 12, the mass analyzer 13, the ion detector 14, the getter pump 23, and the ion pump 24.

[0030] Furthermore, the ion pump 24 adopts a symmetrical assembly structure with upper and lower electrode plates, specifically including an upper electrode plate 2401, a lower electrode plate 2402, and a filament 2403. The upper electrode plate 2401 is fixedly installed on the inner surface of the first substrate 221 facing the third substrate 223, and the lower electrode plate 2402 is fixedly installed on the inner surface of the third substrate 223 facing the first substrate 221. The upper and lower electrode plates 2401 and 2402 are symmetrically arranged around the flight space 3, forming a uniform and stable pumping electric field at the end of the flight space 3, ensuring the uniformity and stability of gas extraction. The filament 2403 is fixedly arranged on the surface of the lower electrode plate 2402. During operation, it works with the upper and lower electrode plates to complete ionization and degassing operations, continuously extracting residual gas inside the vacuum-sealed chamber 22, effectively maintaining a high vacuum environment inside the chamber, and avoiding interference from residual gas on ion transmission and detection.

[0031] Optionally, the ion source 11 is fixedly mounted on the inner surface of the first substrate 221. The upper electrode 1201 of the focusing lens 12 is fixedly mounted on the inner surface of the first substrate 221, and the lower electrode 1202 is fixedly mounted on the inner surface of the third substrate 223. Similarly, the upper analysis electrode 1301 of the mass analyzer 13 is mounted on the inner surface of the first substrate 221, and the lower analysis electrode 1302 is mounted on the inner surface of the third substrate 223. The upper detection electrode 1401 of the ion detector 14 is mounted on the inner surface of the first substrate 221, and the lower detection electrode 1402 is mounted on the inner surface of the third substrate 223. Four getter pumps 23 are provided in total, two of which are mounted on the inner surface of the first substrate 221, and the remaining two are mounted on the inner surface of the third substrate 223, which are symmetrically distributed and arranged around the ion optical path unit 1.

[0032] Furthermore, the ion source 11 is an on-chip ion source, which can be a planar field emission ion source, an on-chip photoelectric effect ion source, an on-chip electron impact ion source, or other on-chip ion sources, enabling effective ionization of the target detection gas. The focusing lens 12 is an on-chip ion focusing lens, which can be a dual-focusing ion source based on a zigzag electrode pair configuration or other planar ion focusing lenses, enabling efficient transmission of target ions.

[0033] Furthermore, the mass analyzer 13 is an on-chip mass analyzer, which can be an on-chip ion trap mass analyzer, a coplanar linear ion trap mass analyzer, a MEMS cycloidal mass analyzer, or other on-chip mass analyzers, enabling effective separation of the analyte ions. The ion detector 14 is an on-chip ion detector, which can be a planar on-chip Faraday detector or other planar ion detectors, enabling effective detection of the target ions. The getter pump 23 is an on-chip getter pump; its quantity and distribution can be customized according to requirements, such as... Figure 4The diagram shows two pairs of symmetrically distributed on-chip getter pumps. Ion pump 24 is an on-chip ion pump, which can be an on-chip ion pump based on an electron emission source, an on-chip ion pump based on a carbon nanotube ion emission source, or other on-chip ion pumps.

[0034] like Figure 5 The diagram illustrates a mass spectrometry analysis method performed using a MEMS mass spectrometry chip, comprising the following steps: S1: The ion source 11 ionizes the gas to be tested to form charged ions. Specifically, the gas to be tested is introduced into the vacuum-sealed chamber 22 through the sample introduction microchannel 21. The ion source 11 mounted on the first substrate 221 ionizes the introduced gas to be tested, ionizing the gas molecules to form a large number of charged ions. The vacuum unit 2 maintains a high vacuum environment inside the chamber throughout the process, which can effectively avoid stray collisions during the ionization of gas molecules and ensure the purity and efficiency of ion ionization.

[0035] S2: The focusing lens 12 focuses the charged ion beam and transmits the charged ions to the mass analyzer 13. Specifically, the charged ions generated by ionization are transmitted forward along the ion flight space 3. The focusing lens 12 forms a uniform electrostatic focusing electric field through the upper electrode 1201 and the lower electrode 1202 of the lens arranged symmetrically above and below, which converges, corrects and focuses the diverging charged ion beam, effectively improves the ion beam dispersion problem, reduces ion transmission loss, and enables the regular and parallel charged ion beam to be stably transmitted to the back-end mass analyzer 13 region.

[0036] S3: The mass analyzer 13 separates ions based on their different mass-to-charge ratios. Specifically, the mass analyzer 13 constructs a stable and uniform analytical electric field through symmetrically arranged upper analytical electrode 1301 and lower analytical electrode 1302, receives focused charged ions, and performs differentiated electric field deflection and screening on the ions based on the differences in their mass-to-charge ratios, thereby achieving the separation of ions with different mass-to-charge ratios.

[0037] S4: Ion detector 14 receives the separated charged ions and completes ion detection; specifically, the single mass-to-charge ratio charged ions separated by mass analyzer 13 continue to travel along the ion flight space 3 and finally arrive at the region of ion detector 14. Ion detector 14 captures charged ions from all directions through the upper detection electrode 1401 and the lower detection electrode 1402 arranged symmetrically, completes the acquisition and conversion of ion signals, and finally outputs the mass spectrometry detection signal (and forms a current signal with reaction signal intensity).

[0038] It should be noted that, through the above-described mass spectrometry analysis process, combined with the chip's symmetrical electrode optical path structure and partitioned vacuum maintenance structure, this invention achieves stable operation of the entire process of ion ionization, focusing, separation, and detection. The coordination between each step is high, significantly improving the accuracy, stability, and sensitivity of micro mass spectrometry detection.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A MEMS mass spectrometry chip, characterized in that, It includes an ion optical path unit (1) and a vacuum unit (2); The vacuum unit (2) surrounds the ion optical path unit (1) and forms an ion flight space (3) inside; the flight space (3) is used to provide a flight path for the ions transported in the ion optical path unit (1); Along the flight path, the ion optical path unit (1) integrates an ion source (11), a focusing lens (12), a mass analyzer (13), and an ion detector (14) arranged in sequence.

2. The MEMS mass spectrometry chip according to claim 1, characterized in that, The focusing lens (12) includes an upper electrode (1201) and a lower electrode (1202); the upper electrode (1201) and the lower electrode (1202) are symmetrically arranged with the flight space (3) as the center.

3. A MEMS mass spectrometry chip according to claim 1, characterized in that, The mass analyzer (13) includes an upper analysis electrode (1301) and a lower analysis electrode (1302); the upper analysis electrode (1301) and the lower analysis electrode (1302) are arranged symmetrically with respect to the flight space (3).

4. A MEMS mass spectrometry chip according to claim 1, characterized in that, The ion detector (14) includes an upper detection electrode (1401) and a lower detection electrode (1402). The upper detection electrode (1401) and the lower detection electrode (1402) are symmetrically arranged with the flight space (3) as the center.

5. A MEMS mass spectrometry chip according to claim 1, characterized in that, The vacuum unit (2) includes a vacuum sealing chamber (22), a getter pump (23), and an ion pump (24). The ion optical path unit (1) is installed inside the vacuum sealed chamber (22), and a sample introduction microchannel (21) is opened at one end; the sample introduction microchannel (21) is used to transport the gas to be tested to the ion source (11) inside the vacuum sealed chamber (22); the getter pump (23) is located inside the vacuum sealed chamber (22) and distributed around the mass analyzer (13); the ion pump (24) is located inside the vacuum sealed chamber (22) and at the end of the ion detector (14) away from the mass analyzer (13).

6. A MEMS mass spectrometry chip according to claim 5, characterized in that, The vacuum-sealed chamber (22) includes a first substrate (221), a second substrate (222) and a third substrate (223) stacked in sequence. The second substrate (222) has a hollow structure, forming the flight space (3) of the ions; The opposing surfaces of the first substrate (221) and the third substrate (223) are used to mount the focusing lens (12), the mass analyzer (13), the ion detector (14), the getter pump (23), and the ion pump (24).

7. A MEMS mass spectrometry chip according to claim 6, characterized in that, The ion pump (24) includes an upper electrode plate (2401), a lower electrode plate (2402), and a filament (2403). The upper electrode plate (2401) is mounted on the surface of the first substrate (221) facing the third substrate (223), and the lower electrode plate (2402) is mounted on the surface of the third substrate (223) facing the first substrate (221). The upper electrode plate (2401) and the lower electrode plate (2402) are symmetrically arranged with the flight space (3) as the center. The filament (2403) is mounted on the surface of the lower electrode plate (2402).

8. A MEMS mass spectrometry chip according to any one of claims 1-7, characterized in that, The ion source (11) is a field emission ion source, an on-chip photoelectric effect ion source, or an on-chip electron bombardment ion source.

9. A MEMS mass spectrometry chip according to any one of claims 1-7, characterized in that, The mass analyzer (13) is an on-chip ion trap mass analyzer, a coplanar linear ion trap mass analyzer, or a MEMS cycloidal mass analyzer.

10. A mass spectrometry analysis method, performed using a MEMS mass spectrometry chip according to any one of claims 1-9, characterized in that, Includes the following steps: The ion source (11) ionizes the gas to be tested to form charged ions; The focusing lens (12) focuses the charged ion beam and transmits the charged ions to the mass analyzer (13). The mass analyzer (13) separates ions based on their different mass-to-charge ratios; The ion detector (14) receives the separated charged ions and completes ion detection.

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