Mass spectrometer

Abstract

A locking mechanism (300) includes a lever (301) and an engaging portion (302). The lever (301) is provided on either a main body (100) or an ion source (200), and can rotate between a locked state in which the ion source (200) is maintained in a closed state with respect to the main body (100), and an unlocked state in which the ion source (200) can be opened with respect to the main body (100). The engaging portion (302) includes a first engaging member (321) and a second engaging member (322) of which at least one can rotate, the first engaging member (321) and the second engaging member (322) engaging with one another in the locked state. In conjunction with the rotation of the lever (301) from the unlocked state to the locked state, at least one of the first engaging member (321) and the second engaging member (322) rotates while the first engaging member (321) and the second engaging member (322) come into contact with one another.

Description

Technical Field

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

Background Art

[0002] In a mass spectrometer such as a liquid chromatography mass spectrometer (LC-MS), an ion source for ionizing components in a sample separated in a liquid chromatograph (LC) is used. The ion source is attached to the main body of the mass spectrometer so as to be openable and closable, and the ion source is opened with respect to the main body during maintenance (see, for example, Patent Document 1 below).

[0003] A vacuum chamber into which ions generated in the ionization chamber are introduced is formed inside the main body. The ionization chamber and the vacuum chamber communicate with each other via a connecting pipe called a desolvation line (DL). The ions generated in the ionization chamber are introduced from the ionization chamber into the vacuum chamber through the connecting pipe, and mass spectrometry is performed.

[0004] The connecting pipe is held by a flange portion (DL flange) constituted by a disk-shaped member. By closing the ion source with respect to the main body, the flange portion is pressed against the main body side by the ion source, and the connecting pipe is fixed. On the other hand, when the ion source is opened with respect to the main body, the pressing force from the ion source on the flange portion is released, and the flange portion and the connecting pipe can be removed.

[0005] An O-ring as a seal member is provided between the ion source and the main body. When the ion source is closed with respect to the main body, the seal member is pressed and elastically deformed, thereby ensuring the airtightness in the ionization chamber.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The mass spectrometer disclosed in Patent Document 1 above is provided with a locking mechanism for locking the ion source in a closed state with respect to the main body. However, in order to sufficiently ensure the airtightness in the ionization chamber, when closing the ion source with respect to the main body, it is necessary to elastically deform the seal member with a large pressing force and lock the ion source with respect to the main body so as to maintain that state.

[0008] In particular, in a small mass spectrometer, it is desirable to have a configuration that can apply a large force with a space-saving structure and easily lock the ion source with respect to the main body.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a mass spectrometer that can easily lock an ion source with respect to a main body with a space-saving structure.

Means for Solving the Problems

[0010] The mass spectrometer according to the present invention includes an ion source, a main body, a connecting pipe, a flange portion, a first seal member, and a locking mechanism. An ionization chamber for ionizing a sample is formed inside the ion source. A vacuum chamber into which ions generated in the ionization chamber are introduced is formed inside the main body, and the ion source is detachably attached. The connecting pipe is detachable from the main body and introduces ions from the ionization chamber into the vacuum chamber. The flange portion holds the connecting pipe and is pressed toward the main body side by a pressing surface formed on the ion source as the ion source is closed with respect to the main body. The first seal member is provided between the flange portion and the pressing surface. The locking mechanism is for locking the ion source in a closed state with respect to the main body.

[0011] The locking mechanism has a lever and an engaging portion. The lever is provided on the main body or the ion source, and is rotatable between a locked state in which the ion source is maintained in a closed state with respect to the main body and an unlocked state in which the ion source can be opened with respect to the main body. The engaging portion includes a first engaging member and a second engaging member, at least one of which is provided rotatably. In the locked state, the first engaging member and the second engaging member engage with each other. As the lever rotates from the unlocked state to the locked state, at least one of the first engaging member and the second engaging member rotates while contacting each other.

Advantages of the Invention

[0012] According to the present invention, with a space-saving structure, the ion source can be easily locked with respect to the main body.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0014] 1. Overall Structure of Mass Spectrometer FIG. 1 is a schematic diagram showing an example of a mass spectrometer 10 according to the present embodiment. The mass spectrometer 10 shown in FIG. 1 is a liquid chromatography mass spectrometer that performs mass spectrometry on components in a sample separated by liquid chromatography. This mass spectrometer 10 includes a liquid chromatography unit 12 and a mass spectrometry unit 14. Note that the present invention is also applicable to mass spectrometers other than liquid chromatography mass spectrometers.

[0015] The liquid chromatography unit 12 includes a column (not shown). During analysis, a mobile phase containing an organic solvent is introduced into the column. A predetermined amount of sample is injected into the mobile phase introduced into the column. The mobile phase into which the sample has been injected is introduced into the column, and each component in the sample is separated as it passes through the column. Each component in the sample separated by the column is sequentially supplied to the mass spectrometry unit 14.

[0016] An ionization chamber 16, a vacuum chamber 18, and an analysis chamber 20 are formed inside the mass spectrometry unit 14. The inside of the ionization chamber 16 is at approximately atmospheric pressure. The vacuum chamber 18 and the analysis chamber 20 are each brought into a vacuum state by driving a vacuum pump (not shown).

[0017] The ionization chamber 16 communicates with the vacuum chamber 18, and the analysis chamber 20 communicates with the vacuum chamber 18. That is, the ionization chamber 16 communicates with the analysis chamber 20 via the vacuum chamber 18. Further, the ionization chamber 16, the vacuum chamber 18, and the analysis chamber 20 are configured such that the degree of vacuum increases step by step in this order.

[0018] A probe 22 is provided in the ionization chamber 16. The probe 22 sprays a liquid sample, for example, by the ESI method (Electrospray ionization method). This is done. In the probe 22, a charge is imparted to the sprayed sample, and charged droplets composed of the charged sample are generated, thereby generating ions derived from each component in the sample. Thus, in the ionization chamber 16, the sample supplied from the liquid chromatograph unit 12 is ionized.

[0019] The ionization chamber 16 and the vacuum chamber 18 are partitioned by a partition wall 24, and a connecting pipe 26 penetrates through the partition wall 24. That is, the connecting pipe 26 communicates the inside of the ionization chamber 16 and the vacuum chamber 18. The connecting pipe 26 is composed of a thin tube called a desolvation line (DL) and is used for desolvation.

[0020] Also, an ion guide 28 for sending ions to the analysis chamber 20 while converging them is provided in the vacuum chamber 18. Note that the vacuum chamber 18 communicating with the ionization chamber 16 may be configured in multiple stages.

[0021] The analysis chamber 20 communicates with the vacuum chamber 18 via a skimmer 30 composed of a small hole. The ions generated in the ionization chamber 16 are introduced from the ionization chamber 16 into the vacuum chamber 18 through the connecting pipe 26, and then flow into the analysis chamber 20 through the skimmer 30.

[0022] In the analysis chamber 20, for example, a quadrupole filter 32 and a detector 34 are provided. The ions flowing from the vacuum chamber 18 into the analysis chamber 20 are separated by the quadrupole filter 32 according to the mass-to-charge ratio, and only the ions having a specific mass-to-charge ratio pass through the quadrupole filter 32. The ions that have passed through the quadrupole filter 32 are incident on the detector 34. In the detector 34, a current corresponding to the number of arrived ions is output as a detection signal.

[0023] According to such a mass spectrometer 10, the ions generated by ionizing the sample in the ionization chamber 16 can be introduced into the vacuum chamber 18, and the ions can be detected by the detector 34.

[0024] In this embodiment, a hollow main body 100 having a vacuum chamber 18 and an analysis chamber 20 formed therein and a hollow ion source 200 having an ionization chamber 16 formed therein are constituted by separate members. The connection pipe 26 is detachable from a partition wall 24 provided on the main body 100.

[0025] The ion source 200 is attached to the main body 100 so as to be openable and closable. By closing the ion source 200 with respect to the main body 100, the ion source 200 faces the partition wall 24, and the ionization chamber 16, the vacuum chamber 18, and the analysis chamber 20 are sealed. Further, by opening the ion source 200 with respect to the main body 100, the connection pipe 26 is exposed to the outside, and the connection pipe 26 can be removed from the main body 100 for maintenance.

[0026] 2. Configuration around the connection pipe FIG. 2 is a schematic cross-sectional view showing an example of the configuration around the connection pipe 26. The connection pipe 26 is formed of a metal having conductivity and heat conductivity, and is held by a flange portion 62 via a connection main body portion 40 as shown in FIG. 2.

[0027] The connection main body portion 40 is provided to heat the connection pipe 26 and surrounds the outer periphery of the connection pipe 26. The connection main body portion 40 is constituted by a heating block 42, a heater 44, a cylindrical member 46, a seal member 48, and the like.

[0028] The heating block 42 is formed of a metal having conductivity and heat conductivity. Further, the heating block 42 includes a protruding portion 42a protruding toward the ionization chamber 16 side.

[0029] Furthermore, a through hole 42b extending in the longitudinal direction thereof is formed in the heating block 42. The connection pipe 26 is inserted into the through hole 42b so as to contact the inner peripheral surface of the through hole 42b. That is, the heating block 42 surrounds the outer periphery of the connection pipe 26.

[0030] The heater 44 is in contact with the heating block 42. The heat of the heater 44 is transmitted to the connection pipe 26 through the heating block 42, thereby heating the connection pipe 26.

[0031] From these, the connection main body 40 heats the connection pipe 26 inserted into the connection main body 40. Note that illustration of wirings and the like for supplying power to the heater 44 is omitted.

[0032] The cylindrical member 46 has a through-hole 46a whose diameter changes stepwise, and the heating block 42 is inserted so as to contact the inner peripheral surface of the through-hole 46a.

[0033] The seal member 48 is constituted by, for example, an O-ring. The heating block 42 is inserted inside the seal member 48, and the outside of the seal member 48 abuts against the inside of the cylindrical member 46. Further, the seal member 48 is sandwiched between the heating block 42 and the cylindrical member 46 in the axial direction of the connection pipe 26.

[0034] A sampling cone 50 is attached to the connection main body 40. The sampling cone 50 is an interface for drawing ions on the ionization chamber 16 side into the connection pipe 26, and is formed of a conductive metal.

[0035] The sampling cone 50 is provided on the ionization chamber 16 side with respect to the connection main body 40. Further, the sampling cone 50 is a conical cylindrical body, and the end portion of the connection pipe 26 is inserted therethrough. Furthermore, the protruding portion 42a of the heating block 42 is inserted inside the sampling cone 50.

[0036] On the side of the vacuum chamber 18 with respect to the connection main body 40, a holding member 52 is provided. The holding member 52 is formed of a metal having conductivity and heat conductivity. A through hole 52a is formed in the holding member 52, and the end portion of the connection pipe 26 is inserted and held in contact with the inner peripheral surface of the through hole 52a. Further, the holding member 52 is fixed to the connection pipe 26 by welding a part of the holding member 52 to the connection pipe 26. Therefore, by displacing the holding member 52 along the axial direction of the connection pipe 26, the connection pipe 26 held by the holding member 52 can be removed from the through hole 42b of the heating block 42 for maintenance.

[0037] Further, the holding member 52 is in contact with the entire end surface 42c of the heating block 42. Thereby, the heat transmitted from the heater 44 to the heating block 42 is favorably transmitted from the end surface 42c to the holding member 52. Further, a part of the holding member 52 is inserted into the opening 24a in the partition wall 24 while protruding toward the vacuum chamber 18 side. Thereby, the connection pipe 26 is inserted into the opening 24a.

[0038] An orifice member 54 is provided in the opening 24a of the partition wall 24. The orifice member 54 is an interface for introducing ions into the vacuum chamber 18. The orifice member 54 is fixed to the partition wall 24 using a fixture 56 such as a screw. A seal member 58 is sandwiched between the holding member 52 and the orifice member 54.

[0039] The ion source 200 is attached to the main body 100 so as to be rotatable about the rotation axis 101. The main body 100 and the ion source 200 are connected via a hinge (not shown) formed of, for example, stainless steel, and the rotation axis 101 is provided on the hinge. The rotation axis 101 may be held by the hinge via a bearing constituted by, for example, a metal cermet oil bush.

[0040] By rotating the ion source 200 around the rotation axis 101, the ion source 200 can be opened and closed with respect to the main body 100. In FIG. 2, a state in which the ion source 200 is closed with respect to the main body 100 is shown. Note that the ion source 200 is not limited to a configuration that is rotatable with respect to the main body 100, and may be configured to be openable and closable with respect to the main body 100 by other means such as sliding with respect to the main body 100.

[0041] In a state where the ion source 200 is closed with respect to the main body 100, the pressing surface 201 of the ion source 200 faces the flange portion 62. The flange portion 62 is a so-called DL flange and is composed of a disk-shaped member. A through hole 62a is formed in the flange portion 62, and the connection main body portion 40 (cylindrical member 46) is inserted through the through hole 62a.

[0042] In the example shown in FIG. 2, as the ion source 200 is closed with respect to the main body 100, the flange portion 62 is pressed toward the main body 100 by the pressing surface 201 of the ion source 200. As a result, the flange portion 62 presses the connection main body portion 40 via the cylindrical member 46, and accordingly, the holding member 52 is pressed toward the vacuum chamber 18 side. Further, when the connection main body portion 40 is pressed by the flange portion 62, the seal members 48 and 58 are elastically deformed respectively.

[0043] A seal member 202 as a first seal member is provided between the flange portion 62 and the pressing surface 201 of the ion source 200. In this example, the seal member 202 is an annular O-ring and is fixed in a recess provided in the pressing surface 201. The seal member 202 is formed of, for example, a low-friction non-sticking fluororubber that is difficult to adhere. However, the seal member 202 is not limited to a configuration attached to the pressing surface 201, and may be attached to the flange portion 62.

[0044] The ion source 200 is locked in a closed state with respect to the main body 100 by the locking mechanism 300. In the locked state shown in FIG. 2, since the ion source 200 is locked by the locking mechanism 300, the ion source 200 cannot be rotated about the rotation axis 101, and the ion source 200 is maintained in a closed state with respect to the main body 100. In the locked state, the seal member 202 is elastically deformed, and the airtightness of the ionization chamber 16 is ensured.

[0045] 3. Configuration of the Locking Mechanism FIGS. 3A to 3C are schematic side views showing an example of the configuration of the locking mechanism 300. Hereinafter, with reference to FIGS. 2 and 3A to 3C, the specific configuration and operation of the locking mechanism 300 will be described.

[0046] The locking mechanism 300 includes a lever 301 and an engaging portion 302. The engaging portion 302 includes a first engaging member 321 and a second engaging member 322 that can engage with each other. The locking mechanism 300 can change the engagement state between the first engaging member 321 and the second engaging member 322 based on an operation of the lever 301 by the user.

[0047] The lever 301 is rotatably attached to the main body 100 about a rotation axis 311. The rotation axis 311 extends in a direction intersecting the rotation axis 101 of the ion source 200, more specifically, in a direction perpendicular thereto. Therefore, the rotation direction D1 of the lever 301 about the rotation axis 311 is different from the rotation direction D2 of the ion source 200 about the rotation axis 101.

[0048] The lever 301 has a support plate 312, and the rotation axis 311 inserted through the insertion hole 312a formed in the support plate 312 is fixed to the main body 100. The lever 301 is configured by, for example, an L-shaped member in a side view by connecting a base portion 313 provided with the support plate 312 and an operation portion 314 for the user to operate. However, the shape of the lever 301 is not limited to such a shape.

[0049] The second engaging member 322 is provided on the lever 301 by being rotatably attached to the support plate 312. Specifically, the second engaging member 322 is inserted into the insertion hole 312b formed in the support plate 312 from one side, and a fastener 323 is attached from the other side of the insertion hole 312b, whereby the second engaging member 322 is rotatably supported within the insertion hole 312b.

[0050] The corner portions of the insertion hole 312b facing the second engaging member 322, that is, the corner portions constituting both end edges of the insertion hole 312b, are chamfered by being cut away so as to form tapered surfaces 312c. Thereby, the second engaging member 322 can be smoothly rotated within the insertion hole 312b.

[0051] Also, the engaging portion 302 includes a thrust washer 324 provided between the insertion hole 312b and the second engaging member 322. The thrust washer 324 is an annular washer for smoothing rotation and is provided at both end edges of the insertion hole 312b. One thrust washer is sandwiched between the head of the second engaging member 322 and the support plate 312, and the other thrust washer is sandwiched between the fastener 323 and the support plate 312. Thereby, the second engaging member 322 can be rotated more smoothly within the insertion hole 312b. A bearing may be provided between the insertion hole 312b and the second engaging member 322.

[0052] Similarly, the corner portions of the insertion hole 312a facing the rotating shaft 311, that is, the corner portions constituting both end edges of the insertion hole 312a, are chamfered by being cut away so as to form tapered surfaces 312c. Also, thrust washers 324 are sandwiched between both end edges of the insertion hole 312a and the rotating shaft 311. Thereby, the support plate 312 (lever 301) can be smoothly rotated about the rotating shaft 311.

[0053] The first engaging member 321 is provided on the ion source 200 by being rotatably attached to the ion source 200. The rotation axis of the first engaging member 321 is parallel to the rotation axis of the second engaging member 322. Further, the outer peripheral surface of the first engaging member 321 is a first contact surface 321a formed of a circumferential surface, and is capable of contacting the outer peripheral surface of the second engaging member 322, which is a second contact surface 322a formed of a circumferential surface, as the lever 301 rotates about the rotation axis 311.

[0054] In the states of FIGS. 2, 3A, and 3B, the first contact surface 321a of the first engaging member 321 and the second contact surface 322a of the second engaging member 322 are in contact with each other, but in the state of FIG. 3C, the first contact surface 321a of the first engaging member 321 and the second contact surface 322a of the second engaging member 322 are not in contact with each other. However, at least one of the first contact surface 321a and the second contact surface 322a may be a surface other than a circumferential surface, such as an arcuate surface, or a surface other than a circumferential shape.

[0055] The states shown in FIGS. 2 and 3A are locked states in which the ion source 200 is maintained in a closed state with respect to the main body 100. In this state, the first engaging member 321 and the second engaging member 322 are engaged with each other. Specifically, the outer peripheral surface of the first engaging member 321 and the outer peripheral surface of the second engaging member 322 are in contact with each other, and the restoring force of the seal member 202 that has been elastically deformed acts from the first engaging member 321 to the second engaging member 322 as indicated by the arrow in FIG. 3A. In this state, since the center (rotation axis) of the first engaging member 321 is located on the side opposite to the rotation direction of the lever 301 at the time of locking with respect to the straight line connecting the center (rotation axis) of the rotation axis 311 and the center (rotation axis) of the second engaging member 322, it is possible to prevent the locked state from being released when an external force such as an impact is applied to the ion source 200 in the locked state.

[0056] The lever 301 has a base 313 connected to the main body 100 via a tension spring 315. As a result, a rotational force acts on the lever 301 in the counterclockwise direction in FIG. 3A about the rotation axis 311. However, in the state of FIG. 3A, since the resistance force acting between the first engaging member 321 and the second engaging member 322 is large, the lever 301 does not rotate, and the locked state is maintained unless the user operates the lever 301.

[0057] When the lever 301 is rotated counterclockwise from the locked state of FIG. 3A, the first contact surface 321a of the first engaging member 321 and the second contact surface 322a of the second engaging member 322 come into contact with each other while the first engaging member 321 and the second engaging member 322 each rotate. At this time, due to the force acting on the lever 301 from the tension spring 315, the lever 301 can be easily rotated with a small force.

[0058] In this way, as the lever 301 rotates, the first engaging member 321 and the second engaging member 322 each rotate, and as shown in FIG. 3B, the ion source 200 can be opened with respect to the main body 100 to a locked state. When the lever 301 is further rotated counterclockwise from the unlocked state of FIG. 3, the first contact surface 321a of the first engaging member 321 and the second contact surface 322a of the second engaging member 322 are separated.

[0059] When the inside of the ionization chamber 16 is in a negative pressure state or the seal member 202 is fixed to the flange portion 62, even if the lever 301 is rotated from the locked state to the unlocked state, the ion source 200 cannot be opened with respect to the main body 100 only by the restoring force of the seal member 202. Therefore, in the present embodiment, as the lever 301 is further rotated counterclockwise from the unlocked state, as shown in FIG. 3C, the pressing member 303 provided on the support plate 312 comes into contact with the ion source 200, and the ion source 200 is pressed in a direction away from the main body 100.

[0060] Thus, the ion source 200 can be forcibly opened with respect to the main body 100 only by operating the lever 301. However, the pressing member 303 is not limited to the configuration provided on the support plate 312, and may be provided on other parts of the locking mechanism 300 such as the lever 301.

[0061] When closing the ion source 200 with respect to the main body 100, an operation opposite to the above operation is performed. That is, after the user closes the ion source 200 with respect to the main body 100, the user rotates the lever 301 from the unlocked state in FIG. 3B to the locked state in FIG. 3A. When closing the ion source 200 with respect to the main body 100, the first engaging member 321 and the second engaging member 322 come into contact with each other before the sealing member 202 abuts against the flange portion 62. Therefore, when closing the ion source 200, it is not necessary to manually apply a force to the ion source 200 to counter the repulsive force of the sealing member 202, and the ion source 200 can be easily locked with respect to the main body 100 by applying a large force only by operating the lever 301.

[0062] As the lever 301 rotates from the unlocked state to the locked state, the first engaging member 321 and the second engaging member 322 rotate while contacting each other. Specifically, as the lever 301 rotates from the unlocked state to the locked state, the first contact surface 321a of the first engaging member 321 and the second contact surface 322a of the second engaging member 322 contact each other, and the first engaging member 321 and the second engaging member 322 each rotate.

[0063] Thereby, while pressing the sealing member 202 against the flange portion 62, the ion source 200 can be locked in a closed state with respect to the main body 100 against the restoring force of the sealing member 202 indicated by the arrow in FIG. 3A.

[0064] The radius of the second contact surface 322a of the second engagement member 322 is larger than the radius of the first contact surface 321a of the first engagement member 321. The ratio of these radii is not particularly limited, but the larger the radius of the second contact surface 322a is with respect to the radius of the first contact surface 321a, the more easily the lever 301 can be rotated from the unlocked state to the locked state with a smaller force.

[0065] However, the lever 301 is not limited to the configuration provided on the main body 100, and the lever 301 may be provided on the ion source 200. That is, by rotating the lever 301 provided on the ion source 200 from the unlocked state to the locked state, the ion source 200 may be locked in a closed state with respect to the main body 100. Further, the configuration is not limited to one in which both the first engagement member 321 and the second engagement member 322 are rotatable, and a configuration in which only one of them is rotatable may be used.

[0066] 4. Detection of rotation of the lever FIGS. 4A and 4B are schematic side views for explaining the detection of the rotation of the lever 301. The main body 100 is provided with a detection unit 400 for detecting the rotation of the lever 301. The detection unit 400 includes a switch 401 and a driven unit 402.

[0067] The switch 401 is, for example, a microswitch, and detects the presence or absence of contact of the driven unit 402 with the contact point 411. When the driven unit 402 is not in contact with the contact point 411 as shown in FIG. 4A, the switch 401 is in the off state, and when the driven unit 402 is in contact with the contact point 411 as shown in FIG. 4B, the switch 401 is in the on state.

[0068] The driven part 402 is rotatable about a rotation axis 421 attached to the main body 100. The rotation axis 421 of the driven part 402 is parallel to the rotation axis 311 of the lever 301. An urging member 422, which is constituted by, for example, a torsion spring, is attached to the driven part 402, and the driven part 402 is urged counterclockwise in FIG. 4A by this urging member 422. However, in the state of FIG. 4A, the driven part 402 is in contact with a stopper (not shown), and it is regulated so as not to rotate counterclockwise from this state.

[0069] In the state of FIG. 4A, the lever 301 is in the unlocked state, and in this state, the lever 301 is not in contact with the driven part 402. When the lever 301 is rotated clockwise from the state of FIG. 4A, a contact portion 304 provided on the lever 301 comes into contact with a contacted portion 423 provided on the driven part 402. Then, when the lever 301 is further rotated clockwise, the contacted portion 423 is pressed by the contact portion 304 against the urging force of the urging member 422, and the driven part 402 rotates clockwise about the rotation axis 421.

[0070] When the lever 301 is rotated to the locked state as shown in FIG. 4B, a part of the driven part 402 comes into contact with the contact point 411 of the switch 401, and the switch 401 switches from the off state to the on state. Based on the signal when the switch 401 switches from the off state to the on state, a control unit (not shown) can detect that the lever 301 has become the locked state.

[0071] On the other hand, when the lever 301 is rotated from the locked state of FIG. 4B to the unlocked state of FIG. 4A, the switch 401 switches from the on state to the off state. In this case, based on the signal when the switch 401 switches from the on state to the off state, the control unit can detect that the lever 301 has become the unlocked state.

[0072] The outside of the detection unit 400 is covered with a cover member 403. A notch 431 is formed in a portion of the cover member 403 that faces the non-contact portion 423, and the contact portion 304 of the lever 301 can enter the inside of the cover member 403 through this notch 431. Since the detection unit 400 is covered with the cover member 403 except for the notch 431, it is possible to prevent a user from accidentally touching the detection unit 400. In addition, it is possible to prevent electromagnetic noise from entering from outside the device via the detection unit 400, and to prevent the electromagnetic noise from adversely affecting the analysis result.

[0073] 5. Gas supply to the ionization chamber FIG. 5 is a schematic plan view for explaining the gas supply to the ionization chamber 16, and a part thereof is shown in cross section. In the present embodiment, a gas (dry gas) is supplied into the ionization chamber 16 to promote the desolvation of charged droplets.

[0074] The main body 100 is provided with a manifold 102 which is a block for supplying gas to the ion source 200. A plurality of gas supply paths 121 are formed in the manifold 102. In this example, three gas supply paths 121 are formed, but the present invention is not limited to this, and a configuration in which two or less or four or more gas supply paths 121 are formed may be used.

[0075] As shown in FIG. 5, the manifold 102 of the main body 100 faces the ion source 200 in a state where the ion source 200 is closed and is close to the ion source 200. Each gas supply path 121 is opened through a gas outlet 122 at a position facing the ion source 200, and the gas in each gas supply path 121 is led out from each gas outlet 122.

[0076] In the ion source 200, a gas inlet 203 is formed at a position facing the manifold 102 of the main body 100 when the ion source 200 is in a closed state. The number of gas inlets 203 is the same as the number of gas outlets 122. When the ion source 200 is closed, each gas inlet 203 faces and is close to each gas outlet 122. As a result, the gas led out from each gas outlet 122 through each gas supply path 121 of the main body 100 is introduced into the ion source 200 from each gas inlet 203. The gas introduced into the ion source 200 from each gas inlet 203 is supplied into the ionization chamber 16 through a pipe (not shown).

[0077] FIG. 6 is a schematic cross-sectional view showing an example of the configuration around the gas outlet 122 and the gas inlet 203. As shown in FIG. 6, when the ion source 200 is closed with respect to the main body 100, a seal member 204 as a second seal member is sandwiched in a compressed state between the main body 100 (manifold 102) and the ion source 200.

[0078] Each seal member 204 is attached to the peripheral edge of each gas inlet 203. Each seal member 204 is an annular O-ring and is formed of, for example, a low-friction non-sticking fluororubber that is difficult to adhere. The inner diameter of each seal member 204 is larger than the inner diameter of each gas inlet 203.

[0079] Each seal member 204 is fixed to the ion source 200 using a fixing member 205. The fixing member 205 is a screw-shaped member in which a shaft portion 251 and a head portion 252 are integrally formed, and is fixed by being screwed into the ion source 200. Generally, the higher the temperature of an O-ring, the easier it is to adhere. Due to the heat of the heating assist gas that promotes desolvation, the ion source 200 is at a higher temperature than the manifold 102. By fixing each seal member 204 to the higher-temperature ion source 200 side, each seal member 204 can be firmly fixed to the ion source 200 by the force of adhesion to the ion source 200, and since it is difficult to adhere to the lower-temperature manifold 102, it is possible to prevent the seal member 204 from adhering to the manifold 102 and falling off from the fixing member 205.

[0080] The shaft portion 251 of the fixing member 205 is a hollow member formed in a cylindrical shape. The outer diameter of the shaft portion 251 substantially coincides with the inner diameter of the gas inlet 203. A thread is formed on the outer peripheral surface of the shaft portion 251, and a thread groove corresponding to the thread is formed in the gas inlet 203. The shaft portion 251 is inserted through the seal member 204 and screwed into the gas inlet 203 of the ion source 200.

[0081] The head portion 252 of the fixing member 205 is an annular member provided at one end of the shaft portion 251. The outer diameter of the head portion 252 is larger than the outer diameter of the shaft portion 251. Thereby, the head portion 252 is formed in a flange shape so as to protrude radially from the outer peripheral surface of the shaft portion 251. A contact surface 253 that contacts the seal member 204 is formed on the head portion 252, and the seal member 204 is pressed and fixed to the ion source 200 side by this contact surface 253.

[0082] The contact surface 253 constitutes the outer peripheral surface of the head portion 252 and is formed by a tapered surface 254 that tapers toward the ion source 200 side (shaft portion 251 side). That is, the head portion 252 is formed such that the outer diameter gradually decreases toward the shaft portion 251 side.

[0083] When the shaft portion 251 of the fixing member 205 is inserted through the seal member 204 and the shaft portion 251 is screwed into the gas inlet 203 of the ion source 200, the inner peripheral surface of the seal member 204 is elastically deformed by the contact surface 253 of the head portion 252, and the inner peripheral surface becomes a tapered surface along the contact surface 253. Thereby, the seal member 204 is more firmly fixed to the ion source 200.

[0084] In a state where the ion source 200 is not closed with respect to the main body, that is, in a state where each seal member 204 is not in contact with the manifold 102, the thickness of the head 252 is equal to or less than the thickness of the seal member 204. Thus, by making the thickness of the head 252 equal to or less than the thickness of the seal member 204, the fixed member 205 (head 252) can be configured not to protrude toward the main body 100 side more than the seal member 204. Therefore, there is no need to adopt a structure in which the fixed member 205 enters the gas outlet 122 provided in the manifold 102. Therefore, even when the position of the ion source 200 is displaced due to manufacturing errors or assembly errors of each member and the center position of the gas outlet 122 and the center position of the gas inlet 203 are displaced, it is possible to prevent the fixed member 205 from contacting the manifold 102 and causing poor gas sealing or generating shaving dust or the like.

[0085] 6. Aspect Those skilled in the art will understand that the above-described plurality of exemplary embodiments are specific examples of the following aspects.

[0086] (Item 1) A mass spectrometer according to one aspect includes an ion source having an ionization chamber formed therein for ionizing a sample, a main body having a vacuum chamber formed therein into which ions generated in the ionization chamber are introduced, and the ion source being detachably attached thereto, a connecting pipe that is detachable from the main body and introduces ions from the ionization chamber to the vacuum chamber, a flange portion that holds the connecting pipe and is pressed toward the main body side by a pressing surface formed on the ion source as the ion source is closed with respect to the main body, a first seal member provided between the flange portion and the pressing surface, and a locking mechanism for locking the ion source in a closed state with respect to the main body. The locking mechanism includes a lever provided on the main body or the ion source and rotatable between a locked state in which the ion source is maintained in a closed state with respect to the main body and an unlocked state in which the ion source can be opened with respect to the main body. including a first engaging member and a second engaging member, at least one of which is rotatably provided, and having an engaging portion where the first engaging member and the second engaging member engage with each other in the locked state, As the lever rotates from the unlocked state to the locked state, at least one of the first engaging member and the second engaging member may rotate while being in contact with each other.

[0087] According to the mass spectrometer described in claim 1, by rotating the lever from the unlocked state to the locked state, at least one of the first engaging member and the second engaging member is rotated while being in contact with each other, and the ion source can be locked in a state closed with respect to the main body. Thereby, since the lever can be rotated with a small force to be in the locked state, the ion source can be easily locked with respect to the main body in a space-saving structure.

[0088] (Claim 2) In the mass spectrometer according to claim 1, the first engaging member and the second engaging member are each rotatably provided with respect to rotation axes parallel to each other, As the lever rotates from the unlocked state to the locked state, a circumferential first contact surface formed on the first engaging member and a circumferential second contact surface formed on the second engaging member are in contact with each other, and each of the first engaging member and the second engaging member may rotate.

[0089] According to the mass spectrometer described in claim 2, since both the first engaging member and the second engaging member are rotatable, the lever can be rotated with a smaller force to be in the locked state.

[0090] (Claim 3) In the mass spectrometer according to claim 2, the first engaging member is provided on the ion source, and the second engaging member is provided on the lever, the radius of the second contact surface may be larger than the radius of the first contact surface.

[0091] According to the mass spectrometer described in claim 3, the lever can be rotated with a smaller force to be in the locked state.

[0092] (Claim 4) In the mass spectrometer described in claim 3, the lever has a support plate that rotatably supports the second engaging member, an insertion hole through which the second engaging member is rotatably inserted is formed in the support plate, and a corner portion of the insertion hole facing the second engaging member may be chamfered.

[0093] According to the mass spectrometer described in claim 4, since the second engaging member can be smoothly rotated within the insertion hole, the lever can be rotated with a smaller force to be in the locked state.

[0094] (Claim 5) In the mass spectrometer described in claim 4, the engaging portion may further have a thrust washer provided between the insertion hole and the second engaging member.

[0095] According to the mass spectrometer described in claim 5, since the second engaging member can be rotated more smoothly within the insertion hole, the lever can be rotated with an even smaller force to be in the locked state.

[0096] (Claim 6) In the mass spectrometer described in claim 1, when the ion source is closed with respect to the main body, the first engaging member and the second engaging member may come into contact before the first sealing member contacts the flange portion or the pressing surface.

[0097] According to the mass spectrometer described in claim 6, when closing the ion source, it is not necessary to manually apply a force to the ion source to counteract the repulsive force of the sealing member, and by only operating the lever, a large force can be applied to easily lock the ion source with respect to the main body.

[0098] (Claim 7) In the mass spectrometer described in claim 1, The lever may be rotatably provided with respect to the main body.

[0099] According to the mass spectrometer described in item 7, the ion source can be locked in a closed state relative to the main body by rotating the lever that is rotatable relative to the main body from an unlocked state to a locked state.

[0100] (Item 8) In the mass spectrometer according to item 7, A detection unit provided on the main body for detecting rotation of the lever; The device may further include a cover member that covers the outside of the detection unit.

[0101] According to the mass spectrometer described in paragraph 8, it is possible to detect whether the lever is in a locked state or an unlocked state. In addition, since the outside of the detection unit is covered with a cover member, it is possible to prevent the user from accidentally touching the detection unit. In addition, it is possible to prevent electromagnetic noise from entering the device from outside via the detection unit, and it is possible to prevent electromagnetic noise from adversely affecting the analysis results.

[0102] (Item 9) In the mass spectrometer according to item 7, The locking mechanism may further include a pressing member that presses the ion source in a direction away from the main body as the lever rotates from the locked state to the unlocked state and further rotates from the unlocked state.

[0103] According to the mass spectrometer described in paragraph 9, by simply operating the lever, the pressing member can press the ion source in a direction away from the main body, forcibly opening the ion source relative to the main body.

[0104] (Item 10) In the mass spectrometer according to item 1, The body is formed with a gas outlet port for introducing gas to be supplied into the ionization chamber, In the ion source, a gas inlet through which the gas from the gas outlet is introduced may be formed such that the ion source is close to the gas outlet in a state where the ion source is closed with respect to the main body, and an annular second seal member may be attached to the peripheral edge of the gas inlet.

[0105] According to the mass spectrometer described in claim 10, by closing the ion source with respect to the main body, the gas outlet of the main body and the gas inlet of the ion source can be communicated in a state sealed by the second seal member.

[0106] (Claim 11) In the mass spectrometer described in claim 10, The ion source further includes a fixing member that fixes the second seal member to the ion source by being screwed into the ion source. The fixing member has a hollow shaft portion that is inserted through the second seal member and screwed into the ion source, and an annular head portion provided at one end of the shaft portion that presses the second seal member toward the ion source side. In a state where the ion source is not closed with respect to the main body, the thickness of the head portion is equal to or less than the thickness of the second seal member. The contact surface of the head portion with the second seal member may include a tapered surface that tapers toward the ion source side.

[0107] According to the mass spectrometer described in claim 11, since the fixing member can be configured not to protrude toward the main body side more than the seal member, even when the ion source is displaced, the fixing member can elastically deform the second seal member well without contacting the main body, and it is possible to prevent the generation of shaving powder or the like due to the fixing member contacting the main body. Further, since the second seal member is fixed to the ion source side where the temperature is high, the second seal member can be firmly fixed to the ion source by the fixing force to the ion source, and it is difficult to adhere to the main body at a low temperature, so it is possible to prevent the second seal member from adhering to the main body and falling off from the fixing member.

Description of Reference Numerals

[0108] 10 Mass spectrometer 16 Ionization chamber 18 Vacuum chamber 26 Connecting pipe 62 Flange part 100 Main body 101 Rotating shaft 122 Gas outlet 200 Ion source 201 Pressing surface 202 Sealing member 203 Gas inlet 204 Sealing member 205 Fixing member 251 Shaft part 252 Head part 253 Contact surface 254 Tapered surface 300 Lock mechanism 301 Lever 302 Engaging part 303 Pressing member 311 Rotating shaft 312a Insertion hole 312b Insertion hole 312c Tapered surface 312 Support plate 321 First engaging member 321a First contact surface 322 Second engaging member 322a Second contact surface 324 Thrust washer 400 Detection part 403 Cover member

Claims

1. An ion source having an ionization chamber formed therein for ionizing a sample, a main body having a vacuum chamber formed therein into which ions generated in the ionization chamber are introduced, and the ion source being detachably attached thereto, a connecting pipe that is detachable from the main body and introduces ions from the ionization chamber to the vacuum chamber, a flange portion that holds the connecting pipe and is pressed toward the main body side by a pressing surface formed on the ion source as the ion source is closed with respect to the main body, a first sealing member provided between the flange portion and the pressing surface, and a locking mechanism for locking the ion source in a closed state with respect to the main body, wherein the locking mechanism includes a lever provided on the main body or the ion source and rotatable between a locked state in which the ion source is maintained in a closed state with respect to the main body and an unlocked state in which the ion source can be opened with respect to the main body, and includes a first engaging member and a second engaging member, at least one of which is rotatably provided, and an engaging portion where the first engaging member and the second engaging member engage with each other in the locked state, and as the lever rotates from the unlocked state to the locked state, the first engaging member and the second engaging member rotate while contacting each other, and at least one of them rotates, a mass spectrometer.

2. The first engaging member and the second engaging member are each rotatably provided with respect to a rotation axis parallel to each other, and as the lever rotates from the unlocked state to the locked state, a circumferential first contact surface formed on the first engaging member and a circumferential second contact surface formed on the second engaging member contact each other, and each of the first engaging member and the second engaging member rotates, the mass spectrometer according to claim 1.

3. The first engaging member is provided on the ion source, and the second engaging member is provided on the lever, and the radius of the second contact surface is larger than the radius of the first contact surface, the mass spectrometer according to claim 2.

4. The lever has a support plate that rotatably supports the second engaging member, and an insertion hole through which the second engaging member is rotatably inserted is formed in the support plate, and a corner portion of the insertion hole facing the second engaging member is chamfered, the mass spectrometer according to claim 3.

5. The mass spectrometer according to claim 4 , wherein the engagement portion further comprises a thrust washer provided between the insertion hole and the second engagement member.

6. 2. The mass spectrometer of claim 1, wherein when the ion source is closed relative to the main body, the first engagement member and the second engagement member come into contact with each other before the first seal member abuts against the flange portion or the pressing surface.

7. The mass spectrometer according to claim 1 , wherein the lever is rotatably provided with respect to the main body.

8. A detection unit provided on the main body for detecting rotation of the lever; The mass spectrometer according to claim 7 , further comprising a cover member that covers an outside of the detection unit.

9. 8. The mass spectrometer according to claim 7, wherein the locking mechanism further includes a pressing member that presses the ion source in a direction away from the main body as the lever rotates from the locked state to the unlocked state and further rotates from the unlocked state.

10. The body is formed with a gas outlet port for introducing gas to be supplied into the ionization chamber, 2. The mass spectrometer according to claim 1, wherein the ion source is formed with a gas inlet that is adjacent to the gas outlet when the ion source is closed relative to the main body and through which gas is introduced from the gas outlet, and a second annular seal member is attached to a peripheral portion of the gas inlet.

11. a fixing member that is screwed into the ion source to fix the second seal member to the ion source; the fixing member has a hollow shaft portion that is inserted through the second seal member and screwed into the ion source, and an annular head portion that is provided at one end of the shaft portion and presses the second seal member toward the ion source, When the ion source is not closed relative to the main body, a thickness of the head is equal to or less than a thickness of the second seal member, The mass spectrometer according to claim 10 , wherein the head portion has an abutment surface with the second seal member that includes a tapered surface that tapers toward the ion source.

Images