Quality analysis device

Abstract

To provide a mass spectroscope comprising an ion detector disposed in a vacuum vessel, the ion detector being replaceable at low operation costs without a lot of effort and time.SOLUTION: A mass spectroscope in one embodiment of the invention comprises a vacuum vessel (7) having an interior to be made into a vacuum atmosphere by evacuation, an analysis unit that is disposed in the interior of the vacuum vessel and includes a mass separator (3) and an ion detector (4), an opening (7C) formed at a predetermined position on a wall face of the vacuum vessel in such a size that the ion detector can pass through, a lid (11) for sealing the opening, and a detector supporting part (10) formed by integrating connections (12 to 14) connecting the lid and the ion director.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a mass spectrometer.

Background Art

[0002] As disclosed in Patent Document 1 and the like, an ion trap time-of-flight mass spectrometer includes an ion trap and a time-of-flight mass separator. In an ion trap time-of-flight mass spectrometer, various ions generated from a sample are once captured inside the ion trap, and then the various ions are accelerated all at once and ejected from the ion trap and introduced into the time-of-flight mass separator. Each accelerated ion has a velocity corresponding to its mass-to-charge ratio (hereinafter sometimes referred to as "m / z"), and while flying through the flight space of the time-of-flight mass separator, the ions are separated according to m / z and reach an ion detector and are detected.

[0003] In a time-of-flight mass spectrometer (hereinafter referred to as TOFMS), generally, the longer the distance the ions fly, the higher the mass resolution obtained. Therefore, compared with a linear configuration in which ions fly linearly, a reflectron type configuration in which ions fly back and forth as disclosed in Patent Document 1 is more likely to obtain a high mass resolution.

[0004] As a TOFMS capable of further extending the flight distance of ions, a multi-turn TOFMS disclosed in Patent Documents 2, 3, etc. is known. The multi-turn TOFMS extends the flight distance of ions by causing the ions to orbit multiple times along the same or substantially the same orbit. In the multi-turn TOFMS, it is possible to significantly extend the flight distance without increasing the size of the apparatus, and it is possible to achieve a high mass resolution while being small in size.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In the mass spectrometers described above, ion detectors such as microchannel plates (MCPs) and secondary electron multiplier tubes are used. These detectors are a type of consumable item, and in order to maintain sufficient sensitivity and accuracy, they need to be replaced with new ones periodically or after a predetermined period of use.

[0007] Generally, in TOFMS, the ion detector is often integrated with the time-of-flight mass separator, and when replacing the ion detector, it is necessary to remove the lid of the chamber housing both the time-of-flight mass separator and the ion detector. On the other hand, in TOFMS, especially in multi-turn TOFMS with long flight distances, the chamber requires high strength to achieve a high vacuum level inside. Therefore, the chamber body and lid are quite thick and heavy, making it difficult for a person to remove or attach the lid on their own for safety reasons. As a result, it is usually necessary to use a small crane to remove or attach the chamber lid, which presents problems in terms of effort, time, and cost when replacing the ion detector.

[0008] This invention was made to solve these problems, and its main objective is to provide a mass spectrometer that allows for easy, and therefore time-consuming, replacement of the ion detector installed in the chamber at a low operational cost. [Means for solving the problem]

[0009] One embodiment of the mass spectrometer according to the present invention, which was developed to solve the above problems, is: A vacuum vessel, in which the interior is evacuated to create a vacuum atmosphere, An analytical unit, including a mass separator and an ion detector, is arranged inside the vacuum vessel. An opening of a size through which the ion detector can pass is formed at a predetermined position on the wall surface of the vacuum container, A detector holding part comprising a lid that closes the opening and a connecting part that connects the lid and the ion detector, It is equipped with. [Effects of the Invention]

[0010] According to the above embodiment of the mass spectrometer of the present invention, the ion detector can be removed from the vacuum vessel by removing the lid of the detector holder that closes the opening formed in the vacuum vessel and pulling out the ion detector held in the detector holder through the opening. This makes it possible to replace the ion detector installed inside the vacuum vessel at a low cost without having to remove a heavy lid used to open and close the vacuum vessel, for example, without requiring much effort or time. [Brief explanation of the drawing]

[0011] [Figure 1] An overall configuration diagram of an ion trap TOFMS, which is one embodiment of the present invention. [Figure 2] A schematic diagram of the main components of the mass spectrometer according to this embodiment. [Figure 3] Enlarged view of section A in Figure 2. [Figure 4] A diagram illustrating the procedure for replacing the ion detector in the mass spectrometer of this embodiment. [Figure 5] A schematic diagram showing a modified ion detector holding mechanism. [Figure 6] A diagram showing the overall configuration of a mass spectrometer, which is another embodiment of the present invention. [Figure 7] A longitudinal section (A) and a top view (B) of an example of a multi-turn mass separator. [Figure 8] Figure 7 shows a top view illustrating the ion orbitals in a multi-turn mass separator.

Best Mode for Carrying Out the Invention

[0012] Hereinafter, an embodiment of a mass spectrometer according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of a mass spectrometer according to an embodiment of the present invention. FIG. 2 is a configuration diagram of a main part of the mass spectrometer according to the present embodiment. Further, FIG. 3 is an enlarged view of the vicinity of part A shown in FIG. 2.

[0013] The mass spectrometer according to the present embodiment is an ion trap TOFMS, and as shown in FIG. 1, it includes an ion source 1, an ion trap 2, a mass separator 3, and an ion detector 4. The ion source 1 is disposed in an ionization chamber 5A formed in a first chamber 5, and the ion trap 2 is disposed in a first vacuum chamber 5B formed in the same first chamber 5. The ionization chamber 5A and the first vacuum chamber 5B are partitioned by a partition wall 6, and the inside of the first vacuum chamber 5B is evacuated by a vacuum pump 8.

[0014] The ion source 1 ionizes a target component contained in a liquid sample or a gas sample. When the sample is a liquid sample, as the ion source 1, for example, an ion source based on an ionization method such as an electrospray ionization method or an atmospheric pressure chemical ionization method is used. When the sample is a gas sample, as the ion source 1, for example, an ion source based on an ionization method such as an electron ionization method or a chemical ionization method is used. Further, when the sample is a solid sample, for example, an ion source based on an ionization method such as a matrix-assisted laser desorption ionization method is used.

[0015] The ion trap 2 is composed of one ring electrode 21 and a pair of two end cap electrodes 22 and 23 arranged so as to sandwich the ring electrode 21. Here, the ion trap 2 has a three-dimensional quadrupole type configuration, but it may have a linear type configuration.

[0016] The mass separator 3 and the ion detector 4 are arranged inside a second chamber (corresponding to the vacuum vessel in this invention) 7, which is roughly rectangular in shape. Here, the mass separator 3 is a multi-turn TOF type mass separator. The second chamber 7 consists of a main body 7A that forms five sides excluding the top surface, and a lid 7B that forms the top surface. The mass separator 3 is supported so as to float in the internal space of the second chamber 7 by a plurality of support columns 40 erected on the bottom surface of the second chamber 7 or on a member fixed to the bottom surface. The ion detector 4 is fixed to this mass separator 3. An exhaust opening 7E is formed in the bottom surface of the main body 7A, and the inside of the second chamber 7 is evacuated to a predetermined vacuum level by a vacuum pump 9 located outside the exhaust opening 7E.

[0017] A brief explanation of a typical measurement operation in the above-mentioned mass spectrometer is provided. Ion source 1 ionizes compounds contained in the introduced sample. The generated ions are introduced into the internal space of ion trap 2. At this time, predetermined voltages are applied to the ring electrode 21 and end cap electrodes 22 and 23 from a power supply unit (not shown), and the resulting electric field traps the ions in the internal space of ion trap 2. Subsequently, predetermined voltages are applied to the end cap electrodes 22 and 23 from the power supply unit, and the ions are given kinetic energy in the X-axis direction in Figure 1 and ejected simultaneously from ion trap 2. The ejected ions enter the internal space of the second chamber 7 through ion passage holes 7F formed in the second chamber 7 and are introduced into the mass separator 3.

[0018] As described later, ions that fly in a circular motion in the mass separator 3 eventually reach the ion detector 4. Since each ion has a velocity dependent on its m / z value when ejected from the ion trap 2, ion species with different m / z values ​​are separated in the mass separator 3 during their flight and enter the ion detector 4 with a time difference. The ion detector 4 outputs a detection signal corresponding to the amount of incident ions. The detection signal from the ion detector 4 is input to a data processing unit (not shown), which converts the flight time from the ion ejection point into m / z values ​​and creates a mass spectrum showing the relationship between m / z values ​​and ion intensity.

[0019] Here, an example of a multi-turn TOF mass separator will be described. Figure 7 shows a longitudinal section (A) and a top view (B) of an example of a multi-turn TOF mass separator, and Figure 8 is a top view showing the ion orbitals in the multi-turn TOF mass separator shown in Figure 7. These configurations are as described in Patent Document 3.

[0020] The mass separator 3 includes a main electrode 31 consisting of an outer electrode 311 and an inner electrode 312, which are approximately ellipsoidal in shape. Figure 7(A) is an end view (vertical end view) of the main electrode 31 in the ZX plane, which is a plane containing the Z-axis, which is the axis of rotation in the approximately ellipsoidal shape of the outer electrode 311 and the inner electrode 312, and the X-axis, which is a unidirectional axis perpendicular to the Z-axis. When the main electrode 31 is cut by a plane containing the Z-axis, it exhibits approximately the same shape as shown in Figure 7(A), regardless of the azimuthal angle (angle around the Z-axis) of its cross-section. Figure 7(B) is a top view of the main electrode 31 viewed from the positive direction of the Z-axis. The axis perpendicular to the Z-axis and X-axis is defined as the Y-axis, and the plane containing the X-axis and Y-axis is defined as the XY plane.

[0021] The outer electrode 311 and inner electrode 312 are a combination of three sets of partial electrode pairs S1, S2, and S3, which are curved in the ZX plane and face each other, and four sets of partial electrode pairs L1, L2, L3, and L4, which are linear in the ZX plane and face each other. Partial electrode pair S2 is positioned at both ends of the main electrode 31 in the ZX plane with respect to the X-axis direction and has a shape that is symmetric with respect to the X-axis. Partial electrode pair S1 is positioned on the positive side in the Z-axis direction of partial electrode pair S2. Partial electrode pair S3 is positioned on the negative side in the Z-axis direction of partial electrode pair S2 and is symmetric with respect to partial electrode pair S1 with respect to the X-axis. Partial electrode pair L2 is positioned between partial electrode pairs S1 and S2. Partial electrode pair L3 is positioned between partial electrode pairs S2 and S3 and has a shape that is symmetric with respect to partial electrode pair L2 with respect to the X-axis. Partial electrode pair L1 has a donut-shaped plate perpendicular to the Z-axis and is positioned on the positive side in the Z-axis direction, inside partial electrode pair S1 in the XY plane. Partial electrode pair L4 is positioned on the negative side in the Z-axis direction, symmetrically with respect to partial electrode pair L1 with respect to the X-axis. Due to the combination of the above multiple partial electrode pairs, the outer electrode 311 and the inner electrode 312 each exhibit a shape that is approximately a spheroid as a whole.

[0022] In the ZX plane, the curved partial electrode pairs S1, S2, and S3 are subjected to a voltage from a power supply unit (not shown) that creates an electric field extending from the outer electrode 311 to the inner electrode 312. On the other hand, in the ZX plane, the linear partial electrode pairs L1, L2, L3, and L4 are subjected to a voltage from the power supply unit that causes the outer electrode 311 and the inner electrode 312 to be at the same potential. This creates a circulating electric field in the circulating space 319 between the outer electrode 311 and the inner electrode 312, causing ions to circulate within that space.

[0023] The outer electrode 311 of the partial electrode pair S1 is provided with an ion inlet 34 for introducing supplied ions into the circulating space 319, as indicated by the arrows in Figures 7 and 8. The ion inlet 34 is positioned slightly offset from the XY plane to the positive side of the Y-axis, and is arranged so that ions are incident approximately parallel to the X-axis. Immediately after the ions are incident into the circulating space 319 from the ion inlet 34, they receive a centripetal force from the circulating electric field of the partial electrode pair S1. Furthermore, as mentioned above, because the ion inlet 34 is offset from the XY plane to the positive side of the Y-axis, the ions receive a force directed in the direction of the XY plane. As a result, the ions orbit the circulating space 319 along an approximately elliptical orbit, and with each revolution, they fly in an orbit 318 (see Figure 8) such that the orbit moves counterclockwise when viewed from the positive side of the Y-axis. Figure 8 shows the ion orbit 318 in a top view of the XY plane.

[0024] On the other hand, the outer electrode 311 of the partial electrode pair S3 is provided with an ion outlet 35 that guides ions that have circled the circulating space 319 multiple times (tens of times) out of the circulating space 319. The ions guided out from the ion outlet 35 travel in a linear trajectory. The ion detector 4 is positioned on this linear trajectory.

[0025] With the above configuration, ions with various m / z values ​​ejected from the ion trap 2 fly through the circulating space 319 within the main electrode 31. During this flight, each ion is spatially separated according to its m / z value and reaches the ion detector 4 with a time difference. In this mass separator 3, the ion's orbit 318 is determined independently of the ion's m / z value, so the flight distance is the same for all ions. As shown in Figure 8, the ion's orbit shifts slightly with each revolution, thus avoiding the problem of ions overtaking each other that would occur if they were orbiting in the same trajectory. It goes without saying that the shape of the orbital in the mass separator 3, or the configuration and structure of the electrodes for forming it, is not limited to those shown in Figures 7 and 8, but various well-known designs can be adopted.

[0026] In mass spectrometers using TOF-type mass separators, including multi-turn TOF-type mass separators, an MCP (or secondary electron multiplier tube) is used as an ion detector. Since the characteristics of such detectors deteriorate with use, they are a type of consumable and need to be replaced with new ones, for example, periodically or after a predetermined period of use. In the mass spectrometer of the above embodiment, the internal space of the second chamber 7 is opened by removing the lid 7B of the second chamber 7, so the ion detector 4 can be removed from the mass separator 3 and replaced. However, the lid 7B is quite heavy for the following reasons.

[0027] In a TOF (Time-of-Flight) mass separator, the presence of residual gas molecules in the flight space increases the likelihood of ions coming into contact with these molecules during flight. As a result, ions with the same m / z value may spread out, leading to a decrease in resolution or a decrease in sensitivity due to ion loss. Therefore, the inside of the vacuum vessel (in this case, the second chamber 7) where the mass separator is located should be kept under high vacuum (e.g., 10°C). -7 ~10 -9 Maintained at Torr, the vacuum vessel is subjected to a large force due to atmospheric pressure. If the vacuum vessel deforms due to this force, the electrodes fixed inside the vessel may deform or move relative to it, reducing assembly accuracy and potentially resulting in suboptimal performance or even electrode damage due to deformation. In particular, in multi-turn TOF mass separators, ions repeatedly travel through trajectories formed by the same electrodes, so the impact of performance degradation due to electrode deformation or displacement as described above is significant. Therefore, the second chamber 7 is constructed with a considerably thick and robust structure to prevent deformation even when such large forces are applied from the outside (atmospheric pressure side), and both the main body 7A and the lid 7B are heavy.

[0028] For these reasons, lifting and removing the lid 7B requires a small crane, making it a rather cumbersome, time-consuming, and costly operation. Performing this operation every time the ion detector 4 needs to be replaced is a significant burden for the user. Therefore, the mass spectrometer of this embodiment employs a structure that facilitates the replacement of the ion detector 4, as described below.

[0029] As shown in Figures 2 and 3, an opening 7C is formed in the lid 7B directly above the ion detector 4 attached to the mass separator 3. The size of this opening 7C is slightly larger than the size of the ion detector 4 when viewed from above. The shape of the opening 7C can be any shape, such as circular, elliptical, or rectangular. This opening 7C is closed by a detector holding mechanism 10, which has the function of holding the ion detector 4.

[0030] The detector holding mechanism 10 includes a lid portion 11 located on the outside of the lid 7B, a holding portion 12 made of an insulating material for holding the ion detector 4, a plurality of support columns 13 with one end fixed to the back surface of the lid portion 11, and an elastic portion 14 inserted between the other end of the support columns 13 and the holding portion 12. Here, the elastic portion 14 is a spring, but it may be another elastic body or elastic member such as rubber. A metal gasket 16 is placed between the lid portion 11 and the lid 7B to maintain airtightness.

[0031] As shown in Figure 3, the ion detector 4 is fixed to the mass separator 3 with screws 15. Preferably, the screws 15 are anti-loosening screws. Furthermore, a small-diameter screw attachment / detachment opening 7D is formed in the main body portion 7A of the second chamber 7 on the extension of the screw insertion position of the screws 15 into the mass separator 3, and the screw attachment / detachment opening 7D is closed by the lid portion 17. The ion detector 4 is fixed to the holding portion 12 of the detector holding mechanism 10, for example, by screws (not shown), thereby integrating the detector holding mechanism 10 and the ion detector 4.

[0032] As shown in Figure 3, when the device is assembled, the ion detector 4 is fixed to the mass separator 3 and connected to the lid 11 via the holding part 12, the elastic part 14, and the support column 13, and is also fixed to the lid 11. However, the elastic part 14 can be moved within a predetermined range in the three axes of X, Y, and Z.

[0033] When replacing the ion detector 4 from the state shown in Figure 3, the operator performs the following steps. First, the lid 17 is removed, and the tip of a special screwdriver is inserted into the second chamber 7 through the screw opening 7D. Then, the screw 15 is turned and removed. This allows the ion detector 4 to be detached from the mass separator 3. Then, the operator holds the lid 11 and pulls the ion detector 4 straight out in the Z-axis direction, as shown in Figure 4. The ion detector 4, which is integrated with the detector holding mechanism 10 including the lid 11, is removed to the outside of the second chamber 7 through the opening 7C.

[0034] When replacing the ion detector 4 with a new one and installing the new ion detector 4 into the device, the process is reversed from the above: insert the ion detector 4 into the second chamber 7 through the opening 7C, attach the lid 11 to the predetermined position on the lid 7B, and then tighten the screws 15 with a screwdriver inserted into the second chamber 7 through the screw attachment / detachment opening 7D. As described above, in the mass spectrometer of this embodiment, the ion detector 4 can be easily replaced without having to open and close the lid 7B, which is time-consuming to open and close.

[0035] As described above, in the mass spectrometer of this embodiment, although the chamber 7 is robust due to the high vacuum level in the second chamber 7, large external forces may cause deformation such as inward bending or distortion of the main body 7A and lid 7B. When this happens, a force acts to move the mass separator 3 via the support column 40, or a force acts to move the ion detector 4 via the lid 11 and support column 13. Even in such cases, the elastic part 14 provided between the support column 13 and the holding part 12 absorbs the force caused by the movement or deformation. Therefore, unwanted forces acting on the ion detector 4 itself and its mounting parts can be reduced, preventing deformation or damage to them.

[0036] In the above embodiment, a screw 15 having both positioning and fixing functions was used to fix the ion detector 4 to the mass separator 3. However, as shown in Figure 5, the ion detector 4 may be positioned by inserting a positioning pin 19 provided on the mass separator 3 into a positioning hole 4A formed in the ion detector 4, and then the ion detector 4 may be fixed to the mass separator 3 with a spring-loaded fixing screw 18.

[0037] Furthermore, for example, a guide may be provided on either the ion detector 4 or the mass separator 3 to guide the other in the Z-axis direction, making it easier for the ion detector 4 to settle into its predetermined position along the guide when it is mounted. Of course, the method of fixing the ion detector 4 to the mass separator 3 is not limited to this, and any well-known and appropriate method can be used.

[0038] Furthermore, it is clear that the detector holding mechanism 10 is not limited to the above configuration and can be modified as appropriate, as long as it integrates a member for closing the opening 7C and a member for holding the ion detector 4, and is capable of holding the ion detector 4 in a predetermined position relative to the mass separator 3.

[0039] Furthermore, although the mass separator 3 in the above embodiment is a multi-turn TOF type mass separator, it is clear that it can be replaced with a suitable mass separator of any type or form, such as a reflectron TOF type mass separator, a multiple reflection TOF type mass separator, or a linear TOF type mass separator.

[0040] Furthermore, it is natural that the configuration other than the vacuum vessel housing the mass separator 3 and the ion detector 4 can also be modified as appropriate. For example, the mass spectrometer in the above embodiment is configured to temporarily store ions generated in the ion source 1 in the ion trap 2 and then send them to the mass separator 3. However, as shown in Figure 6 as an example, it is also possible to configure the system so that ions generated from the sample S in the MALDI ion source 100 and accelerated are directly introduced into the mass separator 3. Specifically, in this configuration, laser light emitted from the laser emission unit 101 is irradiated onto the sample S placed on the sample plate 102, and the components contained in the sample S are ionized. The generated ions are drawn out from the sample plate 102 by the electric field formed by the extraction electrode 103, accelerated by the accelerating electrode 104, and sent into the second chamber 7.

[0041] Furthermore, in addition to the configurations shown in Figures 1 and 6, a mass spectrometer capable of MS / MS analysis can also be created by adding, for example, a collision cell or a pre-stage mass separator.

[0042] Furthermore, the above embodiments and modifications described above are merely examples of the present invention, and it is clear that any modifications, changes, or additions made within the scope of the present invention will be included within the scope of the claims.

[0043] [Various forms] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0044] (Section 1) One embodiment of the mass spectrometer according to the present invention is: A vacuum vessel, in which the interior is evacuated to create a vacuum atmosphere, An analytical unit, including a mass separator and an ion detector, is arranged inside the vacuum vessel. An opening of a size through which the ion detector can pass is formed at a predetermined position on the wall surface of the vacuum container, A detector holding part comprising a lid that closes the opening and a connecting part that connects the lid and the ion detector, It is equipped with.

[0045] According to the mass spectrometer described in paragraph 1, the ion detector can be removed from the vacuum chamber by removing the lid of the detector holder that closes the opening formed in the vacuum chamber and pulling the ion detector held in the detector holder through the opening. This allows the ion detector installed inside the vacuum chamber to be replaced at a low cost without requiring much effort or time, for example, by not having to remove the heavy lid used to open and close the vacuum chamber.

[0046] (Section 2) The mass spectrometer described in Section 1 may further include a fixing part for fixing the ion detector to the mass separator when the detector holding part is mounted on the vacuum container such that the lid part closes the opening.

[0047] According to the mass spectrometer described in paragraph 2, the ion detector can be securely fixed to the mass separator, and the ions separated in the mass separator according to the m / z ratio can be effectively introduced into the ion detector for detection.

[0048] (3) In the mass spectrometer described in paragraph 2, the fixing part may be a member that can be fixed and released by operation through a sub-opening formed in the vacuum vessel, which is different from the opening.

[0049] Here, the member of the fixing part can be, for example, a screw that can be screwed in and removed by rotation, preferably a screw that prevents it from falling out. According to the mass spectrometer described in Section 3, the ion detector can be reliably fixed to the mass separator at a relatively low cost.

[0050] (Article 4) In the mass spectrometer described in Article 1, the connecting portion may include an elastic portion that allows a change in the position of the ion detector relative to the lid portion.

[0051] Here, the elastic part can be a component made of, for example, a spring or rubber. If the ion detector is fixed in place relative to the lid so that its position does not move, then if the mass separator moves due to, for example, deformation of the chamber during vacuuming, force may be applied to the ion detector itself or the components fixing the ion detector and the mass separator, potentially causing damage. In contrast, with the mass spectrometer described in paragraph 4, even if the mass separator moves, the elastic part provided at the connection deforms and absorbs the movement, thus preventing unnecessary force from being applied to the ion detector and fixing components, and thus preventing damage to them.

[0052] (Paragraph 5) In the mass spectrometer described in Paragraph 1, the mass separator may be held at a distance from the inner bottom surface by a plurality of supports that are directly or indirectly fixed to the inner bottom surface of the vacuum vessel.

[0053] According to the mass spectrometer described in paragraph 5, even if deformation occurs in the vacuum vessel due to the pressure difference between the inside and outside of the vacuum vessel, the force acting on the mass separator can be reduced.

[0054] (Article 6) In the mass spectrometer described in any one of paragraphs 1 to 5, the mass separator may be a multi-turn time-of-flight mass separator. By employing a multi-turn time-of-flight mass separator, the flight distance of the ions to be analyzed is increased, thereby improving the ion mass resolution.

[0055] (Section 7) In the mass spectrometer described in Section 6, an ion source and an ion trap capable of ejecting ions to be analyzed may be provided prior to the mass separator.

[0056] According to the mass spectrometer described in Section 7, by temporarily storing the ions generated by the ion source in an ion trap and then subjecting them to mass spectrometry, the amount of ions to be analyzed can be increased, thereby improving analytical sensitivity and accuracy.

[0057] (Clause 8) In the mass spectrometer described in paragraph 6 or 7, an ion source based on matrix-assisted laser desorption ionization may be provided prior to the mass separator.

[0058] In the mass spectrometer described in paragraph 8, it becomes possible to efficiently ionize polymer compounds, for example, without destroying their structure. Therefore, a mass spectrometer suitable for bio-derived polymer compounds can be provided. [Explanation of symbols]

[0059] 1…Ion source 2…Ion trap 3...Mass separator 31...Main electrode 34...Ion inlet 35... Ion outlet 4…Ion detector 4A…Positioning hole 5…First Chamber 5A... Ionization Chamber 5B…1st vacuum chamber 6...Bulkhead 7…Second Chamber 7A…Main unit 7B…Lid body 7C…Opening 7D…Opening for screw insertion and removal 7E... Exhaust opening 7F…Ion passage pores 8, 9… Vacuum pump 10...Detector holding mechanism 11...Lid part 12...Holding part 13…post 14…Elastic part 15... Screw 16…Metal gasket 17...Lid part 18…Spring-loaded fixing screw 19…Positioning pin 40…post 100…MALDI ion source

Claims

1. A vacuum vessel, in which the interior is evacuated to create a vacuum atmosphere, An analytical unit, including a mass separator and an ion detector, is arranged inside the vacuum vessel. An opening of a size through which the ion detector can pass is formed at a predetermined position on the wall surface of the vacuum container, A detector holding part comprising a lid that closes the opening and a connecting part that connects the lid and the ion detector, With the detector holding portion mounted on the vacuum container such that the lid portion closes the opening, the fixing portion fixes the ion detector to the mass separator inside the vacuum container, A mass spectrometer comprising a fixing part, wherein the fixing part is a component that can be fixed and released by operation through a sub-opening formed in the vacuum vessel, which is different from the opening.

2. The mass spectrometer according to claim 1, wherein the connecting portion includes an elastic portion that allows a change in the position of the ion detector relative to the lid portion.

3. The mass analyzer according to claim 1, wherein the mass separator is held at a distance from the inner bottom surface by a plurality of support columns that are directly or indirectly fixed to the inner bottom surface of the vacuum vessel.

4. The mass analyzer according to claim 1, wherein the mass separator is a multi-turn time-of-flight type mass separator.

5. The mass spectrometer according to claim 4, further comprising an ion source and an ion trap capable of ejecting ions to be analyzed, in the preceding stage of the mass separator.

6. The mass spectrometer according to claim 4, further comprising an ion source based on matrix-assisted laser desorption / ionization method prior to the mass separator.

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