Open mass spectrometry imaging device with carbon fiber arc plasma ionization

Abstract

The application discloses an open mass spectrum imaging device ionized by carbon fiber electric arc plasma, which comprises a mass spectrometer, a laser, a carbon fiber and a sample to be detected. The laser emits laser to hit the sample to be detected to release the sample to be detected. The carbon fiber is sleeved with a capillary tube, a sampling and ionization end of the carbon fiber penetrates out of an outlet end of the capillary tube and is located in front of a sample inlet of the mass spectrometer, a discharge reaction gas is introduced into the capillary tube, a stable plasma torch of electric arc is generated at the sampling and ionization end of the carbon fiber after high pressure is applied to the carbon fiber, and the sample to be detected is ionized in the plasma torch to generate sample ions. The mass spectrometer performs mass spectrum analysis and imaging on the sample ions entering through the sample inlet. The device of the application can detect polar and non-polar compounds and heat unstable compounds and can realize open in-situ mass spectrum imaging, has high spatial resolution and sensitivity, is simple to operate, and the generated plasma torch is more stable and is not easy to form a discharge arc with the instrument.

Description

Technical Field

[0001] This application relates to the field of mass spectrometry analysis, specifically to an open-type mass spectrometry imaging device using carbon fiber arc plasma ionization. Background Technology

[0002] Mass spectrometry imaging is an emerging image visualization technique that obtains mass spectrometry data for each pixel by scanning the tissue under test at a fixed step size, thereby providing information on the spatial distribution of molecules in the tissue. Ion sources, as a crucial component of mass spectrometry and mass spectrometry imaging instruments, have always been a hot topic in the field of mass spectrometry analysis. With the continuous development and improvement of various ion source technologies, the range and types of samples that mass spectrometry imaging can detect are constantly expanding, which greatly broadens the application scope of mass spectrometry instruments.

[0003] Mass spectrometry imaging can be categorized into two types based on the sample detection environment: vacuum mass spectrometry and atmospheric pressure mass spectrometry. Vacuum mass spectrometry is most widely used, with matrix-assisted laser desorption / ionization (MALDI) and secondary ion mass spectrometry (SIMS) being the most common methods. Atmospheric pressure mass spectrometry is represented by desorption electrospray ionization (DESI). Ambient mass spectrometry imaging (AMSI) was first proposed by Cooks' research group in 2004. It has gained popularity due to its ability to perform in-situ, real-time visualization analysis of biological samples under atmospheric pressure without requiring sample pretreatment. Currently, it has become an effective analytical tool in various fields such as forensic medicine, metabolomics, disease diagnosis, and drug evaluation.

[0004] DESI-MSI can achieve in-situ two-dimensional distribution analysis of polar molecules (such as metabolites and lipids) in biological tissues under normal pressure conditions without the need for complex sample pretreatment. However, the analytical sensitivity of DESI for nonpolar compounds is significantly limited, mainly due to the low ionization efficiency of its electrospray ionization mechanism for low-polarity substances and the ion suppression effect caused by high-abundance matrix components. Although reactive DESI can improve the ionization efficiency of specific nonpolar molecules through chemical derivatization strategies (such as betaine aldehyde labeling of alcohol hydroxyl groups), its overly strong derivatization targeting makes simultaneous analysis of multiple categories of compounds difficult, and it is limited by droplet diffusion effects and sprayer concentricity deviations, resulting in low ion suppression interference and spatial resolution (>10 μm). Although nano-DESI based on liquid extraction can achieve spatial omics analysis with a resolution better than 10 μm, the analytes must be dissolved in an auxiliary solvent, so poorly soluble or tightly bound components are difficult to detect, and the analysis of substances with low ionization efficiency is also limited.

[0005] MALDI-MSI is a matrix-dependent technique with ultra-high spatial resolution. Due to its good balance between sample pretreatment, chemical sensitivity, and spatial resolution, it has become one of the most commonly used ionization methods in mass spectrometry imaging. Currently, high-resolution MALDI-MSI can stably detect hundreds of metabolites at a spatial scale of <10 μm. However, higher resolution means a need to reduce the laser spot diameter, and ion yield usually decreases simultaneously, forcing researchers to make trade-offs between resolution and signal intensity. Furthermore, MALDI-MSI requires high vacuum conditions, which can lead to spatial metabolite mismatch and significant matrix molecule interference in the low-mass region (<1000 Da), resulting in poor analysis of small molecule metabolites. To address the sensitivity issue, MALDI-2 technology introduces a secondary laser to improve the ionization efficiency of specific molecules by hundreds of times, but the experimental conditions are relatively demanding. Its secondary ionization reaction requires a millibar-level pressure environment, and the post-ionization laser wavelength must be below the two-photon ionization threshold of the matrix molecules.

[0006] Besides the aforementioned MSI technology, SIMS utilizes pulsed primary ion beams to bombard the sample surface and emit secondary ions to ionize target compounds. Due to its high imaging resolution, strong chemical specificity, and ability to observe molecular structures in cells and tissues, it is increasingly regarded as a powerful imaging tool. However, its spatial resolution is often limited by the minimum stepping accuracy of the sample stage (such as the mechanical translation step size), rather than the actual focusing capability of the optical system. Furthermore, the destructive ion beams of SIMS pose challenges to metabolite identification, and signals from low-abundance metabolites and exogenous contaminants are easily buried by background noise. Summary of the Invention

[0007] The purpose of this application is to provide an open-type mass spectrometry imaging device using carbon fiber arc plasma ionization, which can be used to detect polar and non-polar compounds and thermally unstable compounds, and can realize open-type in-situ mass spectrometry imaging. It has high spatial resolution, high sensitivity, and relatively simple operation. The plasma torch generated by this application is more stable and less likely to form a discharge arc with the instrument.

[0008] This application discloses an open-type mass spectrometry imaging device for carbon fiber arc plasma ionization, comprising: a mass spectrometer, a laser, carbon fiber, and a sample to be tested; The laser is configured to emit a laser to strike the sample under test, thereby deattaching the sample under test. The carbon fiber is fitted with a capillary tube. The sampling and ionization end of the carbon fiber extends from the outlet end of the capillary tube and is located in front of the mass spectrometer inlet. The sample to be tested is located between the laser, the sampling and ionization end of the carbon fiber, and the mass spectrometer inlet. A discharge reaction gas is introduced into the capillary tube. After applying high voltage to the carbon fiber, the sampling and ionization end of the carbon fiber generates a plasma torch with a stable discharge arc. The sample to be tested is ionized in the plasma torch to generate sample ions. The mass spectrometer is configured to perform mass spectrometry analysis and imaging of the sample ions that enter through the inlet.

[0009] In a preferred embodiment, it also includes: a sample slide and a two-dimensional moving platform; The sample to be tested is placed on top of the sample slide, which is placed on top of the two-dimensional moving platform. At this time, the sample to be tested is located below the laser and between the sampling and ionization end of the carbon fiber and the inlet of the mass spectrometer. After each laser emitted by the laser strikes a point on the sample to be tested, the two-dimensional moving platform is configured to move the sample carrier and the sample to be tested carried on it along the x-axis or y-axis at a predetermined speed and a predetermined distance until the sample to be tested completes the deattachment of the selected area.

[0010] In a preferred embodiment, a metal tee is also included; The carbon fiber is long and thin, and is covered with an insulating capillary tube. The inlet end of the capillary tube is connected to a gas channel for introducing the discharge reaction gas. The discharge reaction gas is filled into the capillary tube through the gas channel and introduced into the sampling and ionization end of the carbon fiber. The metal two-way valve is configured to be connected to a high-voltage power supply. The voltage applied by the high-voltage power supply causes the desorbed sample to be collected and ionized by the arc plasma torch generated by the sampling and ionization end of the carbon fiber, generating sample ions. The sample ions enter the mass spectrometer through the inlet of the mass spectrometer and are analyzed and imaged by the mass spectrometer.

[0011] In a preferred embodiment, the discharge reaction gas is nitrogen, argon, helium, or a combination thereof.

[0012] In a preferred embodiment, the high-voltage power supply is connected to the carbon fiber via a conductive metal foil.

[0013] In a preferred embodiment, the voltage of the high-voltage power supply is 1 to 5 kV.

[0014] In a preferred embodiment, the laser is positioned above the sample to be tested, more preferably directly above the sample to be tested.

[0015] In a preferred embodiment, the diameter of the sampling and ionization ends of the carbon fiber is 1 to 20 micrometers.

[0016] In a preferred embodiment, the angle between the axis of the carbon fiber and the laser line emitted by the laser is 30 to 45 degrees, more preferably 30 degrees.

[0017] In a preferred embodiment, the angle between the axis of the inlet end of the ion transport tube and the laser line emitted by the laser is 30 to 45 degrees, more preferably 45 degrees.

[0018] In a preferred embodiment, the angle between the laser line emitted by the laser and the surface of the sample to be tested is 45 to 90 degrees.

[0019] In a preferred embodiment, the distance between the emitting end of the laser and the surface of the sample to be tested is 10 to 15 centimeters.

[0020] In a preferred embodiment, the distance between the sampling and ionization end of the carbon fiber and the surface of the sample to be tested is 1 to 5 mm, more preferably 2 mm.

[0021] In a preferred embodiment, the gas channel is a PEek tube, and the outlet end of the PEek tube is connected to the inlet end of the capillary tube by a metal two-way valve. The inlet end of the PEek tube is connected to a high-pressure gas integrated device.

[0022] In a preferred embodiment, the mass spectrometer's inlet is connected to an ion transmission tube, the inlet of which is located near the sample to be tested.

[0023] In a preferred embodiment, the gas flow rate in the gas channel is 0.1-1 liters / minute, more preferably 0.5 liters / minute.

[0024] In a preferred embodiment, the arc plasma formed at the tip of the carbon fiber-coated capillary is determined to be less than 0.005 mA based on the actual current magnitude displayed at the high-voltage power supply terminal.

[0025] In a preferred embodiment, the mass spectrometer's inlet is connected to an ion transmission tube, the inlet of which is located near the sample to be tested.

[0026] In a preferred embodiment, the mass spectrometer can be a common type of mass spectrometer such as a triple quadrupole mass spectrometer, a time-of-flight mass spectrometer, an ion trap mass spectrometer, or a Fourier transform ion cyclotron resonance spectrometer.

[0027] In this embodiment, by introducing discharge reaction gas into the sampling and ionization ends of the carbon fiber, a controlled and stable plasma torch can be formed under high pressure, which significantly improves the stability and controllability of the ionization process, effectively reduces the risk of irregular discharge arcs between the carbon fiber and the mass spectrometer, thereby improving the system's operational reliability and sample ionization efficiency, and ensuring the accuracy and repeatability of mass spectrometry imaging.

[0028] Furthermore, by setting up a two-dimensional moving platform in conjunction with laser deattachment, automated, point-by-point deattachment processing of the sample to be tested can be achieved, improving the imaging efficiency and spatial resolution of large-area samples.

[0029] Furthermore, compared with traditional DESI technology, this application has higher spatial resolution, better compatibility with analytes (DESI is only compatible with polar solvents), stronger ionization capability, a wide range of ionizable molecules, and compatibility with both polar and nonpolar compounds. Moreover, compared with Nano-ESI technology, this application uses laser-assisted desorption of samples, which can effectively improve the response of compounds in mass spectrometry.

[0030] Furthermore, compared with DART, APCI and DBDI technologies, this application can support continuous sample injection, provide stable signals, detect a wider range of molecular weights, eliminate the need for high-temperature ionization of samples, obtain more complete quality information of analytes, and is compatible with thermally unstable compounds.

[0031] The specification of this application contains numerous technical features distributed across various technical solutions. Listing all possible combinations of these technical features (i.e., technical solutions) would make the specification excessively lengthy. To avoid this problem, the various technical features disclosed in the above-described invention, the various technical features disclosed in the following embodiments and examples, and the various technical features disclosed in the accompanying drawings can be freely combined to form various new technical solutions (all of which are considered to have been described in this specification), unless such a combination of technical features is technically infeasible. For example, one example discloses feature A+B+C, and another example discloses feature A+B+D+E. Features C and D are equivalent technical means that serve the same function, and technically only one needs to be used; they cannot be used simultaneously. Feature E can technically be combined with feature C. Therefore, the solution A+B+C+D should not be considered as described because it is technically infeasible, while the solution A+B+C+E should be considered as described. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of an open mass spectrometry imaging device for carbon fiber arc plasma ionization according to one embodiment of this application.

[0033] Figure 2 This is a positive ion mode first-order mass spectrum obtained by direct mass spectrometry imaging using argon as the carbon fiber discharge reaction gas according to one embodiment of this application.

[0034] Figure 3 This is a positive ion mode mass spectrometry image obtained by direct mass spectrometry imaging using argon as the carbon fiber discharge reaction gas according to one embodiment of this application.

[0035] Explanation of reference numerals in the attached figures: 1. Laser; 2. Carbon fiber; 3. Capillary; 4. Metal two-way valve; 5. Two-dimensional moving platform; 6. Sample slide; 7. Sample to be tested; 8. Ion transmission tube; 9. Mass spectrometer inlet; 10. Plasma torch; The angle between the laser line emitted by the laser and the surface of the sample to be tested; The angle between the axis of the carbon fiber and the laser line emitted by the laser; The angle between the axis of the inlet end of the ion transport tube and the laser line emitted by the laser; The distance between the laser emitter and the surface of the sample to be tested; The distance between the sampling and ionization ends of the carbon fiber and the surface of the sample to be tested; The distance between the inlet end of the ion transfer tube and the surface of the sample to be tested. Detailed Implementation

[0036] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0038] This application relates to an open-type mass spectrometry imaging device using carbon fiber arc plasma ionization, the structure of which is as follows: Figure 1 As shown, it includes: a mass spectrometer, a laser, carbon fiber, and the sample to be tested; The laser is configured to emit a laser beam to strike the sample to be tested, thereby desorbing the sample. A capillary tube is fitted around the carbon fiber, with the sampling and ionization end of the carbon fiber extending from the outlet of the capillary tube and positioned in front of the mass spectrometer's inlet. The sample to be tested is located between the laser, the sampling and ionization end of the carbon fiber, and the mass spectrometer's inlet. A discharge reaction gas is introduced into the capillary tube. After applying high voltage to the carbon fiber, a plasma torch with a stable discharge arc is generated at the sampling and ionization end of the carbon fiber. The sample to be tested is ionized within the plasma torch to generate sample ions. The mass spectrometer is configured to perform mass spectrometry analysis and imaging of the sample ions entering through the inlet.

[0039] In an optional embodiment, it may further include: a sample carrier and a two-dimensional moving platform; The sample to be tested is placed on top of the sample slide, which is placed on top of the two-dimensional moving platform. At this time, the sample to be tested is located below the laser and between the sampling and ionization end of the carbon fiber and the inlet of the mass spectrometer. After each laser emitted by the laser strikes a point on the sample to be tested, the two-dimensional moving platform is configured to move the sample carrier and the sample to be tested carried on it along the x-axis or y-axis at a predetermined speed and a predetermined distance until the sample to be tested completes the deattachment of the selected area.

[0040] In an optional embodiment, a metal tee may also be included; The carbon fiber is long and thin, and is covered with an insulating capillary tube. The inlet end of the capillary tube is connected to a gas channel for introducing the discharge reaction gas. The discharge reaction gas is filled into the capillary tube through the gas channel and introduced into the sampling and ionization end of the carbon fiber. The metal two-way valve is configured to be connected to a high-voltage power supply. The voltage applied by the high-voltage power supply causes the desorbed sample to be collected and ionized by the arc plasma torch generated by the sampling and ionization end of the carbon fiber, generating sample ions. The sample ions enter the mass spectrometer through the inlet of the mass spectrometer and are analyzed and imaged by the mass spectrometer.

[0041] In an optional embodiment, the discharge reaction gas and carbon fiber 2 are inside the capillary 3, with carbon fiber 2 acting as a discharge electrode. The discharge of carbon fiber 2 causes the discharge reaction gas to reach an excited state, and ultimately forms plasma at the sampling and ionization end.

[0042] In an optional embodiment, the discharge reaction gas can be a gas such as nitrogen, argon, or helium, or a combination thereof.

[0043] In an optional embodiment, the angle between the laser line emitted by laser 1 and the surface of the sample 7 under test is... It can be 45 to 90 degrees.

[0044] In an optional embodiment, the angle between the axis of the carbon fiber 2 and the laser line emitted by the laser 1 is... 2 is 30 to 45 degrees, more preferably 30 degrees.

[0045] In an optional embodiment, the distance between the emitting end of the laser 1 and the surface of the sample 7 under test is... It can be 10 to 15 centimeters.

[0046] In an optional embodiment, the distance between the sampling and ionization end of the carbon fiber 2 and the surface of the sample 7 to be tested is... 2 can be 1 to 5 millimeters.

[0047] In an optional embodiment, the arc plasma formed at the tip of the capillary 3 covered by the carbon fiber 2 is based on an actual current magnitude of less than 0.005 mA as indicated by the high-voltage power supply.

[0048] In an optional embodiment, the gas channel can be a PEEK tube, with a metal two-way connector 4 connecting the outlet end of the PEEK tube to the inlet end of the capillary tube 3. The inlet end of the PEEK tube is connected to a high-pressure gas integration device. The metal two-way connector 4 and the high-pressure power supply can be connected using a conventional electrical connection method.

[0049] In an optional embodiment, the mass spectrometer's inlet 9 is connected to an ion transfer tube 8, the inlet of which is located near the sample 7 to be analyzed. During mass spectrometry imaging, the generated sample ions enter the mass spectrometer through the ion transfer tube 8 from the mass spectrometer's inlet 9.

[0050] In an optional embodiment, the distance between the inlet end of the ion transport tube 8 and the surface of the sample 7 to be tested is... The preferred diameter is 1-5 mm, with 2 mm being the most preferred.

[0051] In an optional embodiment, the angle between the axis of the inlet end of the ion transport tube 8 and the laser line emitted by the laser 1 is... 3. The preferred temperature is 30-45 degrees Celsius, with 30 degrees Celsius being the most preferred.

[0052] In an optional embodiment, the laser 1, the sampling and ionization end of the carbon fiber 2, and the mass spectrometer inlet 9 are in a separate state, and the relative positions of the three components and their positions relative to the sample 7 can be adjusted.

[0053] In an alternative embodiment, the tip of the capillary 3 coated with carbon fiber 2 generates visible or invisible arc plasma.

[0054] Specifically, the complete process of this embodiment can be as follows: a) Position the sample 7 to be tested between the sampling and ionization ends of the laser 1 and carbon fiber 2 and the sample inlet 9 of the mass spectrometer; b) The laser 1 emits a laser to strike the sample 7 to be tested, causing the sample 7 to deattach; c) The reaction gas is introduced into the sampling and ionization end of carbon fiber 2 through the gas path channel; d) Connect the high-voltage power supply and apply voltage to the metal two-way valve 4 through the high-voltage power supply. The desorbed sample 7 is ionized by the electric arc plasma torch 10 generated by the sampling and ionization end of the carbon fiber 2, and sample ions are generated. e) The generated sample ions enter the mass spectrometer through the inlet 9 and are analyzed and imaged by mass spectrometry.

[0055] To better understand the technical solution of this application, a specific example is provided below. The details listed in this example are mainly for ease of understanding and are not intended to limit the scope of protection of this application.

[0056] Example 1 Mass spectrometry analysis and imaging of mouse kidney tissue sections (20 µm thick) were performed using an open-type mass spectrometry imaging device (with a quadrupole-time-of-flight mass analyzer). The sample slide 6 is placed on top of the two-dimensional moving platform 5, and the sample to be tested 7 (a section of mouse kidney tissue) is placed on top of the sample slide 6, with the sample to be tested 7 positioned between the laser 1, the sampling and ionization end of the carbon fiber 2, and the mass spectrometer inlet 9 (specifically, the inlet end of the ion transmission tube 8 connected to the mass spectrometer inlet 9). The laser 1 emits a laser beam to strike the sample to be tested 7 (the two-dimensional moving platform 5 moves a distance of 300µm after each laser strike on the sample to be tested 7, with a moving speed of 300µm / s). The distance between the laser 1 and the sample to be tested 7 is 15cm, thus detaching the sample to be tested 7. Appendix: The discharge reaction gas is introduced into the sampling and ionization end of carbon fiber 2 through a gas channel, with a distance of 1 mm between the sampling and ionization end and the sample 7 to be tested; the high-voltage power supply is turned on, and a high voltage of 4.0 kV is applied to the metal two-way valve 4. The desorbed sample 7 to be tested is ionized by the arc plasma torch 10 generated at the sampling and ionization end of carbon fiber 2, generating sample ions; the generated sample ions enter the mass spectrometer through the ion transmission tube 8 (the distance between the inlet end of the ion transmission tube 8 and the surface of the sample 7 to be tested is 2 mm) from the sample inlet 9 of the mass spectrometer, and mass spectrometry analysis and imaging are performed by the mass spectrometer. The results are as follows: Figure 2 and Figure 3 As shown.

[0057] like Figure 2 As shown, this is a first-order mass spectrum in positive ion mode obtained by direct mass spectrometry imaging using argon as the auxiliary solvent of carbon fiber 2 in this embodiment. It can be seen that the mass spectrum shows relatively abundant signals at low molecular weight (less than 500 Da), which provides strong data support for biological sample analysis.

[0058] like Figure 3 The image shown is a positive ion mode mass spectrometry image obtained by direct mass spectrometry imaging using argon as the reactive gas of carbon fiber 2 in this embodiment.

[0059] It should be noted that in this patent application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this patent application, if it refers to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0060] All documents mentioned in this application are considered to be incorporated in their entirety into the disclosure of this application so that they can serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. An open-type mass spectrometry imaging device using carbon fiber arc plasma ionization, characterized in that, include: Mass spectrometer, laser, carbon fiber, and sample to be tested; The laser is configured to emit a laser to strike the sample under test, thereby deattaching the sample under test. The carbon fiber is fitted with a capillary tube. The sampling and ionization end of the carbon fiber extends from the outlet end of the capillary tube and is located in front of the mass spectrometer inlet. The sample to be tested is located between the laser, the sampling and ionization end of the carbon fiber, and the mass spectrometer inlet. A discharge reaction gas is introduced into the capillary tube. After applying high voltage to the carbon fiber, a plasma torch with a stable discharge arc is generated at the sampling and ionization end of the carbon fiber. The plasma torch is configured to ionize the sample to be tested to generate sample ions. The mass spectrometer is configured to perform mass spectrometry analysis and imaging of the sample ions that enter through the inlet.

2. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization as described in claim 1, characterized in that, It also includes: sample slides and a two-dimensional moving platform; The sample to be tested is placed on top of the sample slide, which is placed on top of the two-dimensional moving platform. At this time, the sample to be tested is located below the laser and between the sampling and ionization end of the carbon fiber and the inlet of the mass spectrometer. After each laser emitted by the laser strikes a point on the sample to be tested, the two-dimensional moving platform is configured to move the sample carrier and the sample to be tested carried on it along the x-axis or y-axis at a predetermined speed and a predetermined distance until the sample to be tested completes the deattachment of the selected area.

3. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization as described in claim 2, characterized in that, It also includes metal tees; The carbon fiber is long and thin, and is covered with an insulating capillary tube. The inlet end of the capillary tube is connected to a gas channel for introducing the discharge reaction gas. The discharge reaction gas is filled into the capillary tube through the gas channel and introduced into the sampling and ionization end of the carbon fiber. The metal two-way valve is configured to be connected to a high-voltage power supply. The voltage applied by the high-voltage power supply causes the desorbed sample to be collected and ionized by the arc plasma torch generated by the sampling and ionization end of the carbon fiber, generating sample ions. The sample ions enter the mass spectrometer through the inlet of the mass spectrometer and are analyzed and imaged by the mass spectrometer.

4. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The discharge reaction gas is nitrogen, argon, helium, or a combination thereof.

5. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The angle between the laser line emitted by the laser and the surface of the sample to be tested is 45 to 90 degrees.

6. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The angle between the axis of the carbon fiber and the laser line emitted by the laser is 30 to 45 degrees.

7. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The distance between the laser emitter and the surface of the sample to be tested is 10 to 15 centimeters.

8. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The distance between the sampling and ionization end of the carbon fiber and the surface of the sample to be tested is 1 to 5 millimeters.

9. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 3, characterized in that, The gas channel is a PEek tube, and the metal tee is connected between the outlet end of the PEek tube and the inlet end of the capillary tube.

10. The open-type mass spectrometry imaging device for carbon fiber arc plasma ionization according to claim 1, characterized in that, The mass spectrometer has an ion transmission tube connected to its inlet, and the inlet of the ion transmission tube is located near the sample to be tested.

Images