Free radical generator and ion analyzer

Abstract

A technical solution of the free radical generating device of the present invention comprises: a cylindrical tube (410) formed of a dielectric and having a plasma raw material introduced into the inside thereof; an antenna (411) formed of a conductor and wound around the cylindrical tube; an outer conductor part (412) having a conductive inner surface coaxial with the cylindrical tube and having a concentric circular cross section; and a connecting part (420) which is a cylindrical body inserted into a gap between the inner surface of the outer conductor part and the outer surface of the cylindrical tube and connected to the inner surface of the outer conductor part. The circumferential surface and the antenna are in contact and the two are electrically connected. The connecting portion is a double-layer cylindrical tube structure including an inner cylinder (421) and an outer cylinder (424). The ends of the inner cylinder and the outer cylinder on the same side are divided in the circumferential direction by cuts extending in the axial direction to form a plurality of split pieces (421b, 424b), and a conical portion (421c) bulging outward toward the top end side is formed on the outer side of the split piece of the inner cylinder, or a conical portion (421c) bulging inward toward the top end side is formed on the inner side of the split piece of the outer cylinder.

Description

Technical Field

[0001] The present invention relates to a radical generating device and an ion analyzing device for dissociating ions and analyzing them by utilizing radical species generated in the device. Background Art

[0002] Conventionally, the following mass spectrometry apparatus is known: ions derived from sample components are irradiated with free radical species such as hydrogen free radicals, oxygen free radicals, and nitrogen free radicals to dissociate the ions, and mass spectrometry analysis is performed on the generated product ions (see Patent Document 1, Non-Patent Document 1, etc.). For example, for ions derived from peptides, various types of product ions reflecting the structure of the amino acid arrangement of the peptide can be generated by performing such a dissociation operation using free radical species. The structure of the peptide can be inferred by analyzing and observing the mass spectra obtained from these product ions.

[0003] There are several types of free radical generating devices. The free radical generating device carried by the mass spectrometer as described above is preferably as small and lightweight as possible. As such free radical generating devices, free radical generating devices described in non-patent documents 1 and 2 are known. In the free radical generating device, microwave power is supplied to a helical antenna as a conductor wound around a capillary formed of a dielectric such as quartz, and discharge occurs in the capillary due to eddy currents, generating plasma. In addition, a magnet that generates a strong magnetic field is arranged on the outside of the capillary, and the density of the plasma is increased and stabilized by utilizing the electron cyclotron resonance (ECR) of the magnetic field. For the free radical generating device, the generation and maintenance of plasma utilizes local inductive discharge and resonant cyclotron resonance, so it is called ECR-LICP (Electron Cyclotron Resonance-Localized Inductively Coupled Plasma) type.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-191081

[0007] Non-patent literature

[0008] Non-patent document 1: Yuji Simabukuro, 4 others, "Tandem Mass Spectrometry of Peptide Ions by MicrowaveExcited Hydrogen and Water Plasmas", Analytical Chemistry, 2018, Vol.90, No.12, pp.7239-7245

[0009] Non-patent document 2: Yuji Simabukuro, "Comprehensive Study on the Low-energy Atomic Hydrogen Beam: From Production to Velocity Distribution Measurement" (PhD thesis), [online], [retrieved on April 8, 2020], Doshisha University Academic Library, Internet <URL: https: / / doors.doshisha.ac.jp / duar / repository / ir / 27819 / zk1079.pdf> Summary of the invention

[0010] Problem that the invention aims to solve

[0011] In the above-mentioned ECR-LICP type free radical generating device, a substantially cylindrical outer conductor coaxial with the helical antenna (inner conductor) is provided outside the helical antenna, and the outer conductor is grounded. Furthermore, a conductive member inserted into the gap between the helical antenna and the outer conductor is used to electrically connect a part of the helical antenna and the outer conductor, thereby forming an ECR resonant circuit.

[0012] In such a structure, in order to induce appropriate resonance in the ECR resonant circuit, it is necessary to adjust the axial position of the helical antenna electrically connected to the outer conductor for each device. Therefore, there is a strong demand for an adjustment mechanism that can achieve stable electrical connection between the helical antenna and the outer conductor and easily adjust the connection position.

[0013] The present invention solves such problems, and a main object of the present invention is to provide a radical generator that can easily adjust the resonance state for plasma generation and can stably generate radical species with high efficiency.

[0014] Furthermore, another object of the present invention is to provide an ion analysis device capable of performing good structural analysis of a sample by utilizing a dissociation operation of ions using radical species generated using such a radical generating device.

[0015] Solutions for solving problems

[0016] A technical solution of the free radical generating device of the present invention comprises:

[0017] A cylindrical tube, which is formed of a dielectric body and into which a plasma raw material is introduced;

[0018] an antenna formed of a conductor and wound around the cylindrical tube;

[0019] an outer conductor portion, the cylindrical tube passing through the inner portion thereof, the outer conductor portion having an inner circumferential surface which is coaxial with the cylindrical tube and has a concentric circular cross section and is conductive; and

[0020] a connecting portion, which is a cylindrical body inserted into the gap between the inner circumference of the outer conductor portion and the outer circumference of the cylindrical tube, and contacts both the inner circumference of the outer conductor portion and the antenna to electrically connect the two,

[0021] The connecting portion is a double-layer cylindrical tube structure including an inner cylinder and an outer cylinder, and the ends of the inner cylinder and the outer cylinder on the same side are divided in the circumferential direction by a cut extending in the axial direction to form a plurality of split pieces, and a tapered portion bulging outward toward the top end side is formed on the outer side of the split piece of the inner cylinder, or a tapered portion bulging inward toward the top end side is formed on the inner side of the split piece of the outer cylinder.

[0022] Furthermore, one technical solution of the ion analysis device of the present invention is an ion analysis device using one technical solution of the free radical generating device of the above invention, wherein:

[0023] The ion analysis device comprises:

[0024] a reaction section that irradiates ions derived from a target sample with radical species generated by the radical generating device to dissociate the ions; and

[0025] The analyzing unit separates and detects the ion species generated in the reaction unit according to the parameters that characterize the respective ion species.

[0026] Here, the parameters that characterize each ion type may be the mass-to-charge ratio (strictly speaking, italicized "m / z") of the ion, ion mobility, etc. The reaction chamber may be, for example, an ion trap, a collision cell, or the like.

[0027] Effects of the Invention

[0028] In the above technical scheme of the free radical generating device of the present invention, for example, a tapered portion bulging outwardly toward the top end side is formed on the outer side of the segmentation piece of the inner cylinder of the connecting portion. When the outer cylinder is advanced axially relative to the inner cylinder (or conversely the inner cylinder is retreated axially relative to the outer cylinder) from the inner side of the inner cylinder to the top end of the outer cylinder without reaching the position of the tapered portion of the inner cylinder, the top of the segmentation piece of the outer cylinder contacts the tapered portion of the inner cylinder. Moreover, when the outer cylinder is further advanced axially relative to the inner cylinder from this state, the tapered portion of the inner cylinder pushes the segmentation piece of the outer cylinder outwardly, and the segmentation piece of the outer cylinder bends outwardly (i.e., expands). On the contrary, the segmentation piece of the outer cylinder pushes the tapered portion of the inner cylinder inwardly, and the segmentation piece of the inner cylinder bends inwardly.

[0029] That is, each segment of the inner cylinder and the outer cylinder included in the connection part functions as a leaf spring that can be elastically deformed inward and outward. As a result, the segment of the inner cylinder is in close contact with the antenna located inside it, and on the other hand, the segment of the outer cylinder is in close contact with the inner circumference of the outer conductor. In addition, on the contrary, the segment of the inner cylinder receives the rebound force from the antenna, and the segment of the outer cylinder receives the rebound force from the outer conductor, so the contact between the top end (tapered part) of the inner cylinder and the top end of the outer cylinder is also improved. As a result, the part that is a specific position in the axial direction of the antenna and the inner circumference of the outer conductor are stably electrically connected by means of the connection part.

[0030] Thus, according to the free radical generating device of the above technical solution of the present invention, the connection part by the connecting part can be fixed at any position in the axial direction of the antenna. In addition, the stable electrical contact between the antenna and the outer conductor part by the connecting part can be ensured so that the two can be reliably connected. Thus, the free radical generating device can be easily adjusted to a state in which the resonance generated by ECR is well generated and maintained. As a result, plasma can be stably generated inside the cylindrical tube, and the desired free radical species can be stably and efficiently generated by the plasma.

[0031] In addition, the ion analysis device according to the above technical solution of the present invention can stably supply a sufficient amount of free radical species to the reaction chamber, so that the ions derived from the target sample can be dissociated with high efficiency to generate various product ions. As a result, it is possible to collect information useful for the structural analysis of the components (compounds) contained in the target sample and perform the analysis with good accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic configuration diagram of a mass spectrometer which is one embodiment of the ion analyzer of the present invention.

[0033] Figure 2 It is a schematic cross-sectional view of the main part of the radical generating section of the mass spectrometer according to the present embodiment.

[0034] Figure 3 yes Figure 2 The schematic cross-sectional perspective view of the main part of the radical generating unit shown.

[0035] Figure 4 yes Figure 2 An enlarged cross-sectional view of a main portion of the radical generating unit shown.

[0036] Figure 5 It is a perspective partial cross-sectional view showing the structure of a resonator adjustment mechanism included in the radical generating unit. DETAILED DESCRIPTION

[0037] Hereinafter, a radical generating device as one embodiment of the present invention and a mass spectrometer as an example of an ion analyzing device using the radical generating device will be described with reference to the drawings.

[0038] Figure 1 1 is a schematic diagram of the mass spectrometer of the present embodiment. The mass spectrometer is a triple quadrupole mass spectrometer equipped with an atmospheric pressure ion source. The mass spectrometer is usually connected to a liquid chromatograph (LC) at its front stage and is used as a liquid chromatograph mass spectrometer.

[0039] like Figure 1 As shown in FIG. 1 , the mass spectrometer has an ionization chamber 11 and a vacuum chamber 10. The ionization chamber 11 is in an atmosphere of substantially atmospheric pressure. The interior of the vacuum chamber 10 is divided into a plurality of chambers, each of which is evacuated by a vacuum pump (rotary pump and / or turbomolecular pump) not shown in the figure, to form a first intermediate vacuum chamber 12, a second intermediate vacuum chamber 13, and an analysis chamber 14. That is, the mass spectrometer has a structure of a multi-stage differential exhaust system in which the vacuum degree increases sequentially from the ionization chamber 11 of substantially atmospheric pressure to the analysis chamber 14 of high vacuum atmosphere.

[0040] An electrospray ionization (ESI) probe 20 is provided in the ionization chamber 11, and an eluate (sample solution) eluted from a column of LC is introduced into the ESI probe 20. The ionization chamber 11 and the first intermediate vacuum chamber 12 are connected via a thin-diameter desolvation tube 21. An ion guide 22 called a Q array is arranged inside the first intermediate vacuum chamber 12. The first intermediate vacuum chamber 12 and the second intermediate vacuum chamber 13 are connected via a small hole formed at the top of a cone separator (Japanese: スキマー) 23. A multipolar ion guide 24 is arranged inside the second intermediate vacuum chamber 13.

[0041] Inside the analysis chamber 14 maintained at a relatively high vacuum degree, a front-stage quadrupole mass filter 25, a collision chamber 26, a rear-stage quadrupole mass filter 28, and an ion detector 29 are arranged along the linear ion optical axis C. Both the front-stage quadrupole mass filter 25 and the rear-stage quadrupole mass filter 28 have four rod electrodes arranged in parallel with the ion optical axis C in a manner surrounding the ion optical axis C, and have the function of selecting ions according to the mass-to-charge ratio. A free radical generating unit 40 is connected to the collision chamber 26, and the collision chamber 26 has the function of dissociating ions using free radical species such as oxygen free radicals supplied from the free radical generating unit 40. Inside the collision chamber 26, a multipolar ion guide 27 is arranged in a manner surrounding the ion optical axis C. The detection signal detected by the ion detector 29 is input to a data processing unit 31, which is a computer.

[0042] A typical MS / MS analysis operation of the mass spectrometer according to this embodiment will be briefly described.

[0043] The ESI probe 20 applies an electric charge to the supplied sample liquid and sprays the sample liquid into the ionization chamber 11. The sample components in the sprayed charged droplets are ionized in the process of droplet miniaturization and solvent vaporization. The generated ions derived from the sample components are sucked into the desolvation tube 21 by the airflow formed by the pressure difference at both ends of the desolvation tube 21, and transported to the first intermediate vacuum chamber 12. The ions injected into the first intermediate vacuum chamber 12 travel roughly along the ion optical axis C, and are transported to the analysis chamber 14 through the ion guide 22, the throttling part of the cone hole separator 23, and the multipole ion guide 24, and are introduced into the front-stage quadrupole mass filter 25.

[0044] A voltage obtained by adding a DC voltage and a high-frequency voltage is applied to the plurality of rod electrodes constituting the front-stage quadrupole mass filter 25 from a power supply (not shown), and only ions having a specific mass-to-charge ratio corresponding to the voltage selectively pass through the front-stage quadrupole mass filter 25 and are introduced into the collision cell 26. Free radical species such as oxygen free radicals are supplied from the free radical generating unit 40 into the collision cell 26, and the ions (generally referred to as precursor ions) introduced into the collision cell 26 react with the free radical species and dissociate. Various product ions generated by the dissociation converge due to the action of the electric field formed by the ion guide 27, come out of the collision cell 26, and are introduced into the rear-stage quadrupole mass filter 28.

[0045] A voltage obtained by adding a DC voltage and a high-frequency voltage is applied to the plurality of rod electrodes constituting the rear-stage quadrupole mass filter 28, similarly to the front-stage quadrupole mass filter 25, and only product ions having a specific mass-to-charge ratio corresponding to the voltage selectively pass through the rear-stage quadrupole mass filter 28 and reach the ion detector 29. The ion detector 29 outputs a detection signal corresponding to the amount of injected ions to the data processing unit 30.

[0046] For example, in the case where the mass-to-charge ratios of the precursor ions and the product ions are both known, the mass-to-charge ratios of the ions selected by the front-stage quadrupole mass filter 25 and the rear-stage quadrupole mass filter 28 are fixed, and specific product ions generated from the specific precursor ions are repeatedly detected. That is, multiple reaction monitoring (MRM) measurement with a specific mass-to-charge ratio combination as the target is repeated. The data processing unit 30 creates a chromatogram (extracted ion chromatogram) based on the detection signal obtained by the repetition of the MRM measurement, and calculates the concentration (content) of the target sample component based on the area of ​​the peak observed in the chromatogram.

[0047] The mechanism of ion dissociation by the reaction between radical species such as oxygen radicals and ions in the collision cell 26 is not the subject of this specification and is described in various documents other than Patent Document 1, so it is omitted here.

[0048] Next, the structure of the radical generating unit 40 that supplies radical species such as oxygen radicals to the collision chamber 26 will be described in detail.

[0049] The free radical generating unit 40 is the above-mentioned ECR-LICP type free radical generating device, such as Figure 1 As shown, the plasma generating unit 41 , a raw material supply unit 42 , a cooling gas supply source 43 and a microwave power source 44 are included.

[0050] Figure 2 It is a schematic cross-sectional view schematically showing the structure of the plasma generating section 41 of the radical generating section 40 . Figure 3 It is a schematic cross-sectional perspective view of a part of the plasma generating unit 41 . Figure 4 It is an enlarged cross-sectional view of a part of the plasma generating portion 41 . Figure 5 It is a partially cutaway perspective view showing the structure of a resonator adjustment mechanism as a part of the plasma generating unit 41 .

[0051] The plasma generating unit 41 generates plasma based on the plasma raw material supplied from the raw material supply unit 42, and sends the radical species generated in the plasma to the outside, specifically, to the collision chamber 26. The cooling gas supply source 43 supplies appropriately pressurized cooling gas. The microwave power supply 44 supplies power for generating plasma. Here, the plasma raw material is water vapor.

[0052] The plasma generating section 41 includes: a central cylindrical tube 410 formed of quartz (or other dielectrics) which is an insulator and a dielectric; a helical antenna 411 which is a band-shaped conductor (usually metal) wound around the central cylindrical tube 410 in a helical shape; an outer conductor part 412 which has a cylindrical opening coaxial with the central cylindrical tube 410 and whose inner diameter is one circle larger than the outer diameter of the central cylindrical tube 410 and is formed of a conductor; a permanent magnet 413 which is buried in the outer conductor part 412; a housing 414 which holds the outer conductor part 412; a microwave supply connector 416 which is mounted on the housing 414; a cooling gas connection part 415 which is also mounted on the housing 414; and a resonator adjustment mechanism 420 which includes an inner cylinder 421 and an outer cylinder 424 which will be described later. The helical antenna 411 is made of, for example, a material close to pure copper (oxygen-free copper, tough copper, etc.) which has high conductivity and formability. In addition, it is preferable to plate its surface with gold in order to prevent oxidation.

[0053] The interior of the central cylindrical tube 410 is a raw material introduction tube for introducing water vapor as a plasma raw material and is a plasma generation chamber. The microwave supply connector 416 is a coaxial connector, which is connected to the microwave power supply 44 by means of a coaxial cable not shown. The conductive wire of the coaxial connector is connected to one end of the helical antenna 411. In addition, the outer conductor part 412 is grounded, but it is not shown. As described later, a part of the helical antenna 411 and the outer conductor part 412 are electrically connected by means of a resonator adjustment mechanism 420, and the helical antenna 411 is grounded at the connection position. The helical antenna 411, the outer conductor part 412, the resonator adjustment mechanism 420, etc. constitute the resonator of the ECR. The microwave power supply 44 supplies power to the resonator via the coaxial cable and the microwave supply connector 416.

[0054] In the radical generating unit 40 , radical species are generated as follows.

[0055] The water vapor generated in the raw material supply section 42 is supplied to the central cylindrical tube 410. The microwave power supply 44 supplies a microwave current with a frequency of 2.45 GHz to the helical antenna 411. Then, due to the action of the current flowing in the helical antenna 411, induction discharge occurs, and plasma with water vapor as a raw material is locally generated in the axial direction along the inner wall of the central cylindrical tube 410. In addition, when the resonator is adjusted by the resonator adjustment mechanism 420 so that the electron cyclotron frequency of the electrons moving around the magnetic field generated by the permanent magnet 413 coincides with the frequency of the microwave, the density of the plasma is increased and stabilized by ECR. Moreover, with the introduction of new water vapor, free radical species such as oxygen free radicals in the plasma are transported in the central cylindrical tube 410 and discharged from the open end at the end.

[0056] At this time, cooling gas is introduced from the cooling gas supply source 43 to the connection chamber 430 through the cooling gas connection part 415. The cooling gas flows out to the upper part through the cutout parts 421a and 424b of the inner cylinder 421 and the outer cylinder 424 as the helical antenna holding part described later. As a result, when the free radical species are continuously generated, the heating of the helical antenna 411 and other parts can be prevented. In addition, at the same time, when the helical antenna 411 is a metal that is easily oxidized, it also has the effect of preventing its oxidation. When the helical antenna 411 is gold-plated, it is impossible to oxidize, so pure air can be used as the cooling gas. On the other hand, when the helical antenna 411 is not gold-plated, inactive nitrogen can be used as the cooling gas.

[0057] like Figure 3 As shown, the resonator adjustment mechanism 420 for adjusting the resonator of the ECR includes an inner cylinder 421 and an outer cylinder 424 which are coaxial double-layer cylindrical tube structures and a movable handle 425. The inner cylinder 421 is longer than the outer cylinder 424 by a predetermined length. The inner cylinder 421 and the outer cylinder 424 are both elastically deformable components, and copper alloys for springs (beryllium copper, phosphor bronze, etc.) can be used. In addition, in order to reduce contact resistance, it is preferred to plate the surfaces of the inner cylinder 421 and the outer cylinder 424 with gold. In addition, for the sake of convenience of explanation, with respect to the inner cylinder 421 and the outer cylinder 424, the end portion (at the end of the inner cylinder 421 and the outer cylinder 424) on the side that is first inserted into the center cylindrical tube 410 is Figure 3 The lower end in the middle is called the top end, and the opposite end is called the base.

[0058] like Figure 5 As shown in FIG. 1 , the top end of the inner tube 421 is divided into a plurality of segments 421b by a cutout portion 421a parallel to the axis. In this example, there are four segments 421b, but the number is not limited to three or more. A tapered portion 421c is formed at the top end of each segment 421b, which gradually bulges outward from the base side toward the top end. Figure 3 As shown, a fixed handle 423 is installed at the base of the inner tube 421 , and an external threaded portion 422 is provided on the outer periphery of the inner tube 421 within a range extending in the axial direction by a predetermined length from the connection end with the fixed handle 423 .

[0059] On the other hand, the top end of the outer cylinder 424 is also divided into a plurality of segments 424b by a cutout portion 424a parallel to the axis in the same manner as the inner cylinder 421, forming segmentation pieces 424b. In this example, there are four segmentation pieces 424b, but the number is not limited to this as long as it is three or more. In addition, the segmentation pieces 421b and the segmentation pieces 424b may not be the same number. Each segmentation piece 421b, 424b at the top end of the inner cylinder 421 and the outer cylinder 424 functions as an independent leaf spring. The movable handle 425 has a through hole, and the through hole is formed with an internal threaded portion on the inner circumferential surface that is threadedly coupled to the external threaded portion 422 of the inner cylinder 421.

[0060] like Figure 3 and Figure 5 As shown, when in use, the movable handle 425 is installed in a threaded manner with the external threaded portion 422 of the inner cylinder 421, and the inner cylinder 421 passes through the outer cylinder 424. When the inner cylinder 421 passes through the outer cylinder 424, the split piece 421b is elastically deformed inward to avoid the tapered portion 421c from becoming an obstacle.

[0061] like Figure 3 As shown, the user inserts the inner cylinder 421 and the outer cylinder 424 of the resonator adjustment mechanism 420 in an integrated state into the gap 431 between the helical antenna 411 and the inner circumference of the outer conductor part 412 around the central cylindrical tube 410. At this time, the split pieces 421b and 424b of the inner cylinder 421 and the outer cylinder 424 do not elastically deform, the inner circumference of the inner cylinder 421 and the helical antenna 411 maintain a very small gap, and the outer circumference of the outer cylinder 424 rubs against the inner circumference of the outer conductor part 412, and the resonator adjustment mechanism 420 is smoothly inserted.

[0062] like Figure 4 As shown, if the top end of the outer tube 424 is in contact with the tapered portion 421c of the inner tube 421, the helical antenna 411 is grounded at the portion of the elastically deformed inner tube 421 that is in contact. If the grounding position of the helical antenna 411 changes in the axial direction, the resonance state changes, and the state of the generated plasma changes. Therefore, the user changes the grounding position of the helical antenna 411 by moving the resonator adjustment mechanism 420 as a whole, and finds the position where the plasma is well generated. Whether the plasma is well generated can be determined by, for example, monitoring the current supplied from the microwave power supply 44. In addition, for example, by installing an accessory with confirmation glass in one of the plurality of cooling gas connection parts 415, the orange light emission when the plasma is generated can be visually confirmed, thereby determining whether the plasma is well generated.

[0063] When the best grounding position of the helical antenna 411 is found, the user holds the fixed handle 423 and rotates the movable handle 425 while fixing the position of the inner tube 421. Then, the movable handle 425 pushes the base of the outer tube 424, and the outer tube 424 moves forward in the axial direction relative to the inner tube 421. Figure 4 and Figure 5As shown in FIG. 1 , the top end of the segment 424b of the outer tube 424 abuts against the tapered portion 421c of the inner tube 421 and pushes the tapered portion 421c, so that the segment 421b of the inner tube 421 is elastically deformed inward. On the contrary, the segment 424b of the outer tube 424 is elastically deformed outward. As a result, the segment 421b of the inner tube 421 is in close contact with the helical antenna 411, and the segment 424b of the outer tube 424 is in close contact with the inner peripheral surface of the outer conductor portion 412. In addition, the segment 421b and 424b are pushed by the helical antenna 411 and the outer conductor portion 412, respectively, so that the segment 421b of the inner tube 421 and the segment 424b of the outer tube 424 are also in close contact with each other.

[0064] In this way, the electrical connection is improved in each of the sealing surfaces, and the axial contact position is also fixed, so that the plasma is continuously generated well. When re-adjusting the resonator, the movable handle 425 is rotated in the opposite direction to the previous direction, so that the outer cylinder 424 is axially retreated relative to the inner cylinder 421 (in Figure 2 and Figure 4 Just pull it up).

[0065] As described above, in the mass spectrometer of the present embodiment, the ECR resonator of the radical generating unit 40 can be easily adjusted, thereby generating plasma well by the resonator adjustment mechanism 420 , in other words, generating radical species efficiently.

[0066] In the above description, the adjustment is performed by the user rotating the movable handle 425, but a driving source that automatically rotates the movable handle 425 may be provided without relying on manual work. In addition, a component (circuit) that automatically performs adjustment based on the results obtained by monitoring the plasma state, etc. may also be provided.

[0067] Furthermore, in the above-described embodiment, the tapered portion 421 c is provided on the inner cylinder 421 , but similar adjustment can be performed by providing a tapered portion on the outer cylinder 424 .

[0068] Furthermore, the mass spectrometer of the above-mentioned embodiment is a triple quadrupole mass spectrometer, but it is obvious that the present invention can also be applied to other types of mass spectrometers having a collision chamber or an ion trap for dissociating ions using free radical species. Specifically, the present invention can also be applied to, for example, a quadrupole-time-of-flight mass spectrometer, an ion trap mass spectrometer, an ion trap time-of-flight mass spectrometer, and the like.

[0069] Furthermore, it is obvious that the present invention can also be applied to an ion mobility analyzer, an ion mobility-mass spectrometer, and the like that separate and detect ions dissociated by radical species according to ion mobility.

[0070] The above-described embodiments and modifications are merely examples of the present invention, and even if modifications, corrections, additions, etc. are appropriately made within the scope of the gist of the present invention, they are naturally included in the claims of the present application.

[0071] [Various forms]

[0072] It will be understood by those skilled in the art that the above-described multiple exemplary embodiments are specific examples of the following aspects.

[0073] (Item 1) One form of the free radical generating device of the present invention comprises:

[0074] A cylindrical tube, which is formed of a dielectric body and into which a plasma raw material is introduced;

[0075] an antenna formed of a conductor and wound around the cylindrical tube;

[0076] an outer conductor portion, the cylindrical tube passing through the inner portion thereof, the outer conductor portion having a conductive inner peripheral surface coaxial with the cylindrical tube and having a concentric circular cross section; and

[0077] a connecting portion, which is a cylindrical body inserted into the gap between the inner circumference of the outer conductor portion and the outer circumference of the cylindrical tube, and contacts both the inner circumference of the outer conductor portion and the antenna to electrically connect the two,

[0078] The connecting portion is a double-layer cylindrical tube structure including an inner cylinder and an outer cylinder, and the ends of the inner cylinder and the outer cylinder on the same side are divided in the circumferential direction by a cut extending in the axial direction to form a plurality of split pieces, and a tapered portion bulging outward toward the top end side is formed on the outer side of the split piece of the inner cylinder, or a tapered portion bulging inward toward the top end side is formed on the inner side of the split piece of the outer cylinder.

[0079] In the free radical generating device described in the first item, the multiple split pieces formed in the inner cylinder and the outer cylinder respectively function as leaf springs. When the outer cylinder is moved relative to the inner cylinder in the axial direction, the inner cylinder and the outer cylinder are in close contact with the antenna and the outer conductor part respectively due to the action of the leaf springs. Therefore, according to the free radical generating device described in the first item, the connection part by means of the connection part can be fixed at any position in the axial direction of the antenna. In addition, the stable electrical contact between the antenna and the outer conductor part by means of the connection part can be ensured at the same time so that the two can be reliably connected. Thus, the device can be easily adjusted to a state where the resonance generated by ECR is well generated and maintained in this state. As a result, plasma can be stably generated inside the cylindrical tube, and the desired free radical species can be stably and efficiently generated using the plasma.

[0080] (Item 2) In the free radical generating device described in Item 1, it can be set as follows: a conical portion is formed on the outer side of the split piece of the inner cylinder body and bulges outward toward the top end side, and the connecting portion includes a moving mechanism that moves the outer cylinder body toward the top end relative to the inner cylinder body.

[0081] According to the radical generating device described in item 2, the outer cylinder can be moved to fix the position of the connecting portion while maintaining the position where the segmented pieces of the inner cylinder are in contact with the antenna. Therefore, the above-mentioned device can be easily adjusted.

[0082] (Item 3) In the radical generating device described in Item 2, it can be configured as follows: the moving mechanism includes a movable handle that is movable in the axial direction of the inner cylinder and pushes the outer cylinder.

[0083] (Item 4) In addition, in the radical generating device described in Item 3, it can be set as the following structure: the movable handle is threadedly connected to the outer peripheral surface of the inner cylinder, and the outer cylinder is pushed by rotating the movable handle.

[0084] According to the radical generating device described in Items 3 and 4, the adjustment mechanism is simple and the cost can be easily suppressed. In addition, the user can also easily perform the adjustment manually.

[0085] (Item 5) One aspect of the ion analysis device of the present invention is an ion analysis device using the radical generating device described in any one of Items 1 to 4, wherein:

[0086] The ion analysis device comprises:

[0087] a reaction section that irradiates ions derived from a target sample with radical species generated by the radical generating device to dissociate the ions; and

[0088] The analyzing unit separates and detects the ion species generated in the reaction unit according to the parameters that characterize the respective ion species.

[0089] According to the ion analysis device described in item 5, a sufficient amount of free radical species can be stably supplied to the reaction chamber, so that ions derived from the target sample can be dissociated with high efficiency to generate various product ions. Thus, it is possible to collect information useful for structural analysis of components (compounds) contained in the target sample and perform the analysis with good accuracy.

[0090] Description of Reference Numerals

[0091] 10. Vacuum chamber; 11. Ionization chamber; 12. First intermediate vacuum chamber; 13. Second intermediate vacuum chamber; 14. Analysis chamber; 20. ESI probe; 21. Desolvation tube; 22, 24, 27. Ion guide; 23. Cone separator; 25. Front quadrupole mass filter; 26. Collision chamber; 28. Rear quadrupole mass filter; 29. ​​Ion detector; 30. Data processing unit; 40. Free radical generation unit; 41. Plasma generation unit; 410. Central cylindrical tube; 411. Helical antenna; 412. Outer guide Body; 413, permanent magnet; 414, shell; 415, cooling gas connection; 416, microwave supply connector; 420, resonator adjustment mechanism; 421, inner cylinder; 421a, 424a, cutout; 421b, 424b, split piece; 421c, tapered portion; 422, external threaded portion; 423, fixed handle; 424, outer cylinder; 425, movable handle; 430, connecting chamber; 431, gap; 42, raw material supply; 43, cooling gas supply source; 44, microwave power supply; C, ion optical axis.

Claims

1. A free radical generating device, wherein: The free radical generating device comprises: A cylindrical tube, which is formed of a dielectric body and into which a plasma raw material is introduced; an antenna formed of a conductor and wound around the cylindrical tube; an outer conductor portion, the cylindrical tube passing through the inner portion thereof, the outer conductor portion having a conductive inner peripheral surface coaxial with the cylindrical tube and having a concentric circular cross section; and a connecting portion, which is a cylindrical body inserted into the gap between the inner circumference of the outer conductor portion and the outer circumference of the cylindrical tube, and contacts both the inner circumference of the outer conductor portion and the antenna to electrically connect the two, The connecting portion is a double-layer cylindrical tube structure including an inner cylinder and an outer cylinder, and the ends of the inner cylinder and the outer cylinder on the same side are divided in the circumferential direction by a cut extending in the axial direction to form a plurality of split pieces, and a tapered portion bulging outward toward the top end side is formed on the outer side of the split piece of the inner cylinder, or a tapered portion bulging inward toward the top end side is formed on the inner side of the split piece of the outer cylinder.

2. The free radical generating device according to claim 1, wherein A tapered portion that bulges outward toward the distal end is formed on the outer side of the split piece of the inner cylinder, and the connecting portion includes a moving mechanism that moves the outer cylinder toward the distal end relative to the inner cylinder.

3. The free radical generating device according to claim 2, wherein: The moving mechanism includes a movable handle that is movable relative to the inner cylinder in the axial direction and pushes the outer cylinder.

4. The free radical generating device according to claim 3, wherein: The movable handle is threadedly coupled to the outer peripheral surface of the inner cylinder, and the outer cylinder is pushed by rotating the movable handle.

5. An ion analysis device using the radical generating device according to claim 1, wherein: The ion analysis device comprises: a reaction section that irradiates ions derived from a target sample with radical species generated by the radical generating device to dissociate the ions; and The analyzing unit separates and detects the ion species generated in the reaction unit according to the parameters that characterize the respective ion species.

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