Ion analyzer and ion analysis method

Abstract

To differentiate an ion generated by reaction between a non-radicalized molecule and an ion and an ion generated by radial-induced dissociation on a mass spectrum, and satisfactorily carry out structural analysis .SOLUTION: One aspect of an ion analyzer is an ion analyzer that brings a radical into contact with an ion derived from a sample and dissociates the ion in a reaction chamber (132). The ion analyzer comprises: a generation chamber (210) into which a raw material gas which is the source of the radical is introduced; a power supply unit (25) for supplying electric power for causing an electrical discharge to occur inside the generation chamber; a raw material supply unit (26) for supplying the raw material gas to the reaction chamber through the generation chamber; and a control unit (3) which controls the raw material supply unit and the power supply unit, and which switchably carries out a radical generation mode of making the raw material gas flow into the generation chamber to supply electric power to the generation chamber and a raw material gas introduction-only mode of making the raw material gas flow to the generation chamber and not to supply electric power to the generation chamber.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ion analysis device and an ion analysis method for analyzing ions derived from a target component contained in a sample. [Background technology]

[0002] In order to identify sample components such as polymer compounds contained in a sample and to analyze their structures, mass spectrometry is widely used, in which ions having a specific m / z (mass-to-charge ratio) are selected from ions derived from the sample components, and the ions are dissociated to generate various product ions, which are separated and detected according to m / z. Various methods are known for dissociating ions, one of which is the radical-induced dissociation method (also called the "radical attachment dissociation method," but referred to as the "radical-induced dissociation method" in this specification), in which ions are dissociated by attaching various radicals to the ions or reacting with them.

[0003] For example, Patent Document 1 describes a method of irradiating ions with hydroxyl (OH) radicals, oxygen radicals, nitrogen radicals, etc. generated by high-frequency discharge to cause radical-induced dissociation, and then subjecting the product ions thus generated to mass spectrometry. Patent Document 2 describes that the double bond position that determines the bioactivity of lipids can be analyzed by MS / MS analysis using the radical-induced dissociation method using hydroxyl radicals and oxygen radicals.

[0004] Patent Document 3 describes an example of a radical generator for generating radicals used in the above-mentioned radical induced dissociation method. This radical generator has a quartz tube and a helical antenna configured by winding a strip-shaped conductor around the quartz tube. A raw material gas such as water vapor is introduced into the quartz tube, and high-frequency (microwave) power is supplied to the helical antenna to generate plasma inside the quartz tube, and radicals are generated in the plasma. In addition, a magnet that generates a strong magnetic field is placed outside the quartz tube, and the density of the plasma in the quartz tube is increased and the generation of the plasma is stabilized by electron cyclotron resonance using this magnetic field. This radical generator uses local inductive discharge and electron cyclotron resonance to generate and maintain plasma, and is therefore sometimes called an ECR-LICP (Electron Cyclotron Resonance - Localized Inductively Coupled Plasma) type.

[0005] In the radical-induced dissociation method, various radical species can be used, and it is desirable to use different radical species depending on the purpose of analysis, the type of compound, and the like. In order to use various radical species with one mass spectrometer, it is only necessary to switch the type of raw material gas supplied to the radical generator as described above. For example, the mass spectrometer described in Patent Document 4 employs a configuration in which hydroxyl radicals, oxygen radicals, and hydrogen radicals can be selectively introduced into the collision cell by switching between water vapor and hydrogen gas as the raw material gas. Hydrogen radicals can be used to dissociate ions, and also have the function of removing an oxide film formed on the surface of an electrode in a collision cell by hydroxyl radicals, etc., due to their reducing action. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2018 / 186286 [Patent Document 2] International Publication No. 2019 / 155725 [Patent Document 3] International Publication No. 2022 / 059247 [Patent Document 4] International Publication No. 2021 / 053865 Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, the radical generator generates radicals from source gases such as water vapor and hydrogen gas. However, not all water vapor and hydrogen molecules in the source gas become radicals. In reality, many water vapor and hydrogen molecules that are not radicalized are also introduced into the collision cell. Since water vapor and hydrogen molecules are highly reactive, in the collision cell, not only do ions derived from the target sample react with radicals, but also the ions may react with water vapor and hydrogen molecules that are not radicalized. The likelihood of the latter reaction occurring depends on the type of sample, etc. When such a reaction between a non-radical particle and an ion occurs, in the mass spectrum obtained by MS / MS analysis using radical-induced dissociation (hereinafter referred to as "radical-induced MS / MS analysis"), it becomes difficult to distinguish between the peaks of product ions generated by reaction with radicals and the peaks of ions generated by reaction with non-radical particles, which causes problems in the analysis of the mass spectrum.

[0008] The present invention has been made to solve the above-mentioned problems, and a main object of the present invention is to provide an ion analysis device and an ion analysis method that can accurately distinguish and analyze ions generated by a reaction between ions derived from a target sample and a component in a raw material gas that is the source of radicals, and ions generated by a reaction with radicals. [Means for solving the problem]

[0009] One aspect of the ion analyzer according to the present invention is an ion analyzer that dissociates ions derived from a sample by bringing radicals into contact with the ions in a reaction chamber, the ion analyzer comprising: a generation chamber into which a source gas serving as a radical is introduced; A power supply unit that supplies power to generate a discharge inside the generation chamber; a raw material gas supply unit that supplies the raw material gas to the reaction chamber through the generation chamber; a control unit for controlling the raw material gas supply unit and the power supply unit, switchably implementing a radical generation mode in which the raw material gas is caused to flow into the generation chamber and power is supplied to the generation chamber, and a raw material gas only introduction mode in which the raw material gas is caused to flow into the generation chamber and power is not supplied to the generation chamber; Equipped with.

[0010] One aspect of the ion analysis method according to the present invention is an ion analysis method comprising: introducing radicals generated in a generation chamber into a reaction chamber; and contacting the radicals with ions derived from a sample in the reaction chamber to dissociate the ions, the method comprising the steps of: a first step of supplying a source gas that is a source of radicals to the reaction chamber through the generation chamber and supplying power to the generation chamber for generating a discharge, thereby performing an analysis in a state in which the source gas can be radicalized; a second step of supplying the source gas to the reaction chamber through the generation chamber and not supplying the power to the generation chamber, thereby performing an analysis in a state in which the source gas cannot be radicalized; has. Effect of the Invention

[0011] In the above-mentioned aspect of the present invention, various gases can be used as the source gas, but typically, water vapor, hydrogen, oxygen, nitrogen, air, etc. In a mass spectrometer capable of radical-induced MS / MS analysis, radicals are used to dissociate ions derived from a target sample, so when the source gas is passed through the generation chamber into the reaction chamber, a predetermined power is generally supplied to the generation chamber to generate radicals. In contrast, in the above-mentioned aspect of the present invention, it is possible to selectively implement an operation mode in which the source gas is introduced directly into the reaction chamber without intentionally generating radicals in the generation chamber.

[0012] According to the above-mentioned aspect of the present invention, it is possible to obtain mass spectrometry data in a state where ions derived from a sample can react with particles (molecules) in the source gas without radical-induced dissociation of the ions, which could not be obtained by this type of conventional ion analyzer. As a result, for example, based on both mass spectrometry data in a state where radical-induced dissociation does not occur and mass spectrometry data obtained by radical-induced MS / MS analysis for the same sample, it is possible to accurately distinguish between ions generated by the reaction between ions derived from a sample and components in the source gas and ions generated by the reaction between ions derived from a sample and radicals, and to easily and accurately perform structural analysis of compounds in the sample. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a mass spectrometer according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a configuration diagram of a main part of a radical production device in the mass spectrometer of the present embodiment. [Diagram 3] FIG. 2 is a functional block diagram of a data processing unit in FIG. 1. [Figure 4] 4 is a control flowchart for acquiring m / z calibration information in the mass spectrometer of this embodiment. [Diagram 5] 4 is a control flowchart when a structural analysis is performed in the mass spectrometer of the present embodiment. [Figure 6] 5 is a control flowchart for performing a degassing operation in the mass spectrometer of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] An embodiment of an ion analysis apparatus and an ion analysis method according to the present invention will be described with reference to the accompanying drawings. A mass spectrometer will be described below as an embodiment of the ion analysis apparatus, but it will be clear from the following description that the present invention is not limited to this and may be an ion mobility spectrometer or an ion mobility-mass spectrometer.

[0015] 1 is a schematic diagram of a mass spectrometer according to the present embodiment. This mass spectrometer is a quadrupole time-of-flight (Q-TOF) mass spectrometer equipped with an atmospheric pressure ion source.

[0016] As shown in Fig. 1, this mass spectrometer includes an ionization chamber 10 and a vacuum chamber 1. The inside of the ionization chamber 10 is at approximately atmospheric pressure. The inside of the vacuum chamber 1 is divided into a plurality of compartments (four compartments in this embodiment), which are, starting from the side closest to the ionization chamber 10, a first intermediate vacuum chamber 11, a second intermediate vacuum chamber 12, a first analysis chamber 13, and a second analysis chamber 14. Each of these chambers is evacuated by a vacuum pump (a rotary pump and / or a turbo molecular pump) (not shown), and the degree of vacuum increases from the ionization chamber 10 to the second analysis chamber 14, forming a multi-stage differential pumping system.

[0017] The ionization chamber 10 is provided with an electrospray ionization (ESI) probe 101 that applies an electric charge to a liquid sample and sprays it. The ionization chamber 10 and the first intermediate vacuum chamber 11 are connected to each other through a thin-diameter desolvation tube 102. The first intermediate vacuum chamber 11 and the second intermediate vacuum chamber 12 are separated by a skimmer 112 having a small hole at the top. The first intermediate vacuum chamber 11 and the second intermediate vacuum chamber 12 are provided with ion guides 111 and 121, respectively. The first analysis chamber 13 is provided with a quadrupole mass filter 131 that separates ions according to m / z, a collision cell 132 that includes a multipole ion guide 133 therein, and an ion transport electrode 134 for transporting ions along the ion optical axis C. The quadrupole mass filter 131 and the multipole ion guide 133 are each composed of a plurality of rod electrodes, and the ion transport electrode 134 is composed of a plurality of ring-shaped electrodes.

[0018] An opening 1320 is formed in the wall of the collision cell 132, and a cylindrical tube connection member 1321 is provided so that one end of the tube connection member 1321 surrounds the opening 1320. A quartz tube 210 extending from the radical generation unit 2 is inserted into the inside of the tube connection member 1321, and the end of the quartz tube 210 protrudes into the collision cell 132 through the opening 1320. In the collision cell 132, as described below, ions are dissociated by radicals supplied from the radical generation unit 2. In addition, a CID gas supply pipe 136 for supplying a gas (typically argon gas) for collision induced dissociation (CID) is connected to the collision cell 132, and the other end of the CID gas supply pipe 136 is connected to the collision cell 132 and is connected to a CID gas supply unit 135 outside the vacuum chamber 1. In addition, a gas valve 137 for permitting / stopping the flow of gas is provided in the CID gas supply pipe 134.

[0019] The second analysis chamber 14 is equipped with an ion transport electrode 141 for transporting ions incident from the first analysis chamber 13, an orthogonal acceleration section 142 including a pair of electrodes arranged opposite to each other across the ion optical axis C, an acceleration electrode 143, a flight tube 144 forming a flight space therein, a reflectron electrode 145 forming a return trajectory of the ions in the flight space, and an ion detector 146 for detecting ions. The ion detector 146 is, for example, a multichannel plate type detector. A detection signal by the ion detector 146 is input to the data processing section 4. Although the illustration of signal lines is omitted except for some, the control section 3 controls the radical generation section 2, the data processing section 4, and a power supply for applying voltages and the like to each section.

[0020] A typical radical-induced MS / MS analysis in the mass spectrometer having the above configuration, which is performed under the control of the control unit 3, is as follows. The ESI probe 101 sprays a liquid sample supplied from, for example, a column outlet of a liquid chromatograph into the ionization chamber 10 while imparting an electric charge to the liquid sample, thereby ionizing the compounds in the liquid sample. The generated ions are sent to the first intermediate vacuum chamber 11 through the desolvation tube 102. The ions that enter the first intermediate vacuum chamber 11 are sent to the first analysis chamber 13 via the ion guide 111, the small hole of the skimmer 112, and the ion guide 121, and then introduced into the quadrupole mass filter 131.

[0021] Among the various ions introduced, only ions having a specific m / z value selectively pass through a quadrupole mass filter 131 and are introduced into a collision cell 132. Radicals are introduced into the collision cell 132 from a radical generator 2 through a quartz tube 210, and the ions introduced into the collision cell 132 react with the radicals and dissociate. Various product ions generated by dissociation leave the collision cell 132 and are introduced into an orthogonal accelerator 142 via ion transport electrodes 134 and 141.

[0022] The ions introduced into the orthogonal acceleration unit 142 along the ion optical axis C are ejected in a direction substantially orthogonal to the ion optical axis C at an appropriate timing. The ejected ions are accelerated by the acceleration electrode 143 and introduced into a flight space in a flight tube 144. The ions fly in a return flight due to an electric field formed by the reflectron electrode 145, and finally reach an ion detector 146. The ion detector 146 outputs a detection signal according to the amount of the incident ions to the data processing unit 4. The time from when the ions leave the orthogonal acceleration unit 142 to when they reach the ion detector 146, that is, the flight time of the ions, depends on the m / z value of the ions. Therefore, the data processing unit 4 creates a time-of-flight spectrum showing the relationship between the flight time and the ion intensity based on the detection signal, and creates a mass spectrum by converting the flight time into an m / z value.

[0023] In this mass spectrometer, instead of introducing radicals from the radical generation unit 2 into the collision cell 132 through the quartz tube 210, a method of introducing a CID gas into the collision cell 132 through a CID gas supply pipe 136 to dissociate ions derived from the sample introduced into the collision cell 132 by CID may also be adopted. In this case, various product ions generated by CID are introduced from the collision cell 132 through the ion transport electrodes 134 and 141 into the orthogonal acceleration unit 142, and are subjected to mass analysis in the same manner as in the above-mentioned radical-induced MS / MS analysis.

[0024] Fig. 3 is a block diagram of the data processing unit 4 shown in Fig. 1. The data processing unit 4 includes, as functional blocks, a data storage unit 41, an m / z calibration information calculation unit 42, an m / z calibration information storage unit 43, an m / z calibration unit 44, and a data analysis unit 45. The function (operation) of each functional block will be described later.

[0025] Next, the detailed configuration and operation of the radical production unit 2 will be described. 1, the radical generating unit 2 includes a plasma generating unit 21. The plasma generating unit 21 generates plasma based on a raw material gas such as water vapor supplied from a raw material gas supply source 26, and supplies radicals generated in the plasma to a collision cell 132. A microwave power source 25 supplies microwave power for generating plasma to the plasma generating unit 21.

[0026] The raw material gas supply source 26 includes a water vapor supply pipe 260 provided with a first mass flow controller (MFC) 262, a hydrogen supply pipe 261 provided with a second MFC 263, a water storage unit 264 connected to the inlet end of the water vapor supply pipe 260, a hydrogen cylinder 265 connected to the inlet end of the hydrogen supply pipe 261, and a manual opening and closing valve 266 provided in the hydrogen supply pipe 261 between the second MFC 263 and the hydrogen cylinder 265. The other ends of the water vapor supply pipe 260 and the hydrogen supply pipe 261 are both connected to the quartz tube 210. The water storage unit 264 includes a heater (not shown), and the water vapor generated by heating the stored water can be supplied through the water vapor supply pipe 260. Note that the hydrogen cylinder 265 and the manual opening and closing valve 266 are part of the raw material gas supply source 26, but are components that are added as necessary and are not included in the mass spectrometer of this embodiment.

[0027] FIG. 2 is a vertical cross-sectional view of the main part, focusing on the plasma generating part 21. As shown in FIG. The plasma generating unit 21 includes a long and thin quartz tube 210, a helical antenna 211 which is a strip-shaped conductor wound in a spiral shape around the outer periphery of a part of the quartz tube 210, an outer conductor part 212 which is coaxial with the quartz tube 210 and has a cylindrical opening whose inner diameter is slightly larger than the outer diameter of the quartz tube 210, a permanent magnet 213 embedded in the outer conductor part 212, a casing 214 which holds the outer conductor part 212, and a permanent magnet 215 which is disposed at the bottom of the casing 214. The casing 214 is provided with a microwave supply connector 216, an ultraviolet light source 217, and a photodetector 218. When the ultraviolet light source 217 irradiates the quartz tube 210 with deep ultraviolet light, electrons are emitted from the wall surface of the quartz tube 210, and the electrons induce the lighting (ignition) of the plasma.

[0028] The quartz tube 210 is a raw material introduction tube into which the raw material gas is introduced from the raw material gas supply source 26, and a part of its inside serves as a generation chamber and a radical flow path. The microwave supply connector 216 is a coaxial connector, and is connected to the microwave power source 25 via a coaxial cable. The conductive wire of the microwave supply connector 216 is connected to one end (the lower end in FIG. 2) of the helical antenna 211. Although not shown, the outer conductor 212 is grounded. A part of the helical antenna 211 and the outer conductor 212 are electrically connected via the resonator adjustment mechanism 220, and the helical antenna 211 is grounded at the connection position. The helical antenna 211, the outer conductor 212, the resonator adjustment mechanism 220, and the like constitute an electron cyclotron resonance resonator. The resonator adjustment mechanism 220 is used to adjust the resonator, and is described in, for example, Patent Document 3.

[0029] This plasma generating section 21 has a configuration called ECR-LICP type, which utilizes local inductively coupled discharge and electron cyclotron resonance to generate and maintain plasma.

[0030] A substantially disk-shaped magnet holder 221 is attached to the bottom surface of the casing 214. The casing 214 and the magnet holder 221 function as a holding member 222 that holds the quartz tube 210. An opening is formed in the center of the magnet holder 221 to insert the quartz tube 210. As shown in FIG. 2, the plasma generating unit 21 is attached to the outer surface of the vacuum chamber 1, and the quartz tube 210 held by the holding member 222 is inserted into the inside of a tube connecting member 1321 that connects the collision cell 132 and the vacuum chamber 1, and reaches the inside of the collision cell 132. Since the inside of the quartz tube 210 and the inside of the collision cell 132 are connected to each other, the inside of the quartz tube 210 is also in a vacuum state when no raw material gas is supplied to the quartz tube 210.

[0031] As described above, in the mass spectrometer of this embodiment, the source gas supplied from the source gas supply source 26 passes through the quartz tube 210 and reaches the collision cell 132, but the source gas is converted into radicals in the pipeline along the way, which corresponds to the generation chamber. The radicals thus generated are introduced into the collision cell 132 and contribute to radical-induced dissociation.

[0032] In this mass spectrometer, in order to create a mass spectrum, m / z calibration information is required to convert the time of flight into an m / z value. In general, such m / z calibration information is obtained based on the results of measuring a standard sample whose precise m / z value is known. In a conventional mass spectrometer that does not include a radical generator 2 and is capable of performing ion dissociation by CID, an appropriate amount of CID gas (argon) is introduced into the collision cell 132 as a cooling gas through the CID gas supply pipe 136, and a standard sample is introduced into the ionization chamber 10 and mass analyzed to obtain m / z calibration information.

[0033] Although the m / z calibration information thus obtained may be used for m / z calibration in radical-induced MS / MS analysis, the inventors have found that this may cause a problem of large mass deviation. In radical-induced MS / MS analysis, a source gas such as water vapor or hydrogen gas is introduced into the collision cell 132 instead of a CID gas (or in some cases in addition to the CID gas), and the state of the gas in the collision cell 132 changes from when only the CID gas is introduced. The gas state here refers to the gas concentration (density) and the size of the gas molecules. Such a change in the state of the gas affects the kinetic energy and velocity of the ions introduced into the collision cell 132. Therefore, the kinetic energy and velocity of the ions when they are ejected from the orthogonal acceleration unit 142 also change from when only the CID gas is introduced into the collision cell 132, which is considered to result in a mass deviation.

[0034] Therefore, in the mass spectrometer of this embodiment, m / z calibration information for radical-induced MS / MS analysis is acquired in advance, and the time of flight of the time-of-flight spectrum acquired in the radical-induced MS / MS analysis can be converted to an m / z value using the information. When acquiring m / z calibration information for radical-induced MS / MS analysis, it is necessary to perform mass analysis on a standard sample for calibration in a state where a source gas is introduced from the radical generation unit 2 into the collision cell 132. Although it is possible to perform mass analysis on a standard sample in a state where radicals can be generated in the radical generation unit 2, in this case, a sample that is dissociated by radical-induced dissociation cannot be used, and the types of samples that can be used as a standard sample are limited. In contrast, in the mass spectrometer of this embodiment, mass analysis is performed on a standard sample using a source gas only introduction mode in which source gas is flowed through the quartz tube 210 in the same manner as in the radical-induced MS / MS analysis, but microwave power is not supplied to the helical antenna 211.

[0035] The operation of the mass spectrometer of this embodiment for obtaining m / z calibration information for radical-induced MS / MS analysis will be described below with reference to the control flow chart of FIG.

[0036] For example, when an instruction to execute an m / z calibration information acquisition operation is given through an input unit (not shown), the control unit 3 that receives this instruction sets the raw material gas only introduction mode as the operation mode (step S1). In the raw material gas only introduction mode, the control unit 3 controls one or both of the MFCs 262 and 263 so that one or both of water vapor and hydrogen gas flow into the quartz tube 210 at a predetermined gas flow rate. For example, the first MFC 262 can be controlled so that water vapor with a gas flow rate of 0.3 sccm flows into the quartz tube 210. Also, the MFCs 262 and 263 can be controlled so that water vapor with a gas flow rate of 0.3 sccm and hydrogen gas with a gas flow rate of 0.2 sccm flow into the quartz tube 210. Meanwhile, the control unit 3 does not operate the microwave power supply 25. As a result, the raw material gas whose flow rate has been adjusted as described above passes through the quartz tube 210 and is introduced directly into the collision cell 132.

[0037] As described above, with the source gas introduced into the collision cell 132, an appropriate standard sample is electrostatically sprayed into the ionization chamber 10 from the ESI probe 101 or from an ESI sprayer dedicated to standard samples (not shown). Then, ions generated from this standard sample are guided to the orthogonal acceleration unit 142 through the ion guides 111, 121, quadrupole mass filter 131, collision cell 132, and ion transport electrodes 134, 141, and then ejected from the orthogonal acceleration unit 142 into the flight space in the flight tube 144 for mass analysis. At this time, the signal obtained by the ion detector 146 is converted into digital data and temporarily stored in the data storage unit 41 (step S2).

[0038] In the data processing unit 4, the m / z calibration information calculation unit 42 creates a time-of-flight spectrum based on the data stored in the data storage unit 41, and calculates m / z calibration information for converting the time-of-flight into an m / z value from the actual flight time corresponding to the peak top of the peak appearing in the spectrum and the known m / z value (precise value) of the compound in the standard sample. Note that the m / z calibration information does not have to be information for converting the time-of-flight into an m / z value, and may be, for example, the deviation (m / z correction value) between the m / z value calculated from the actual flight time based on a theoretical formula and the known m / z value (precise value). The m / z calibration information calculated in this way is stored in the m / z calibration information storage unit 43 (step S3).

[0039] The m / z calibration information thus stored in the m / z calibration information storage unit 43 is used to calculate a mass spectrum from the time-of-flight spectrum acquired in radical-induced MS / MS analysis of an arbitrary sample. That is, when data is obtained by performing radical-induced MS / MS analysis of an arbitrary sample, the m / z calibration unit 44 in the data processing unit 4 converts the time-of-flight into an m / z value using the m / z calibration information stored in the m / z calibration information storage unit 43 to create a mass spectrum. The m / z calibration information used at this time has high accuracy because it reflects the analysis results performed under almost the same conditions as when the radical-induced MS / MS analysis was performed, except for whether or not radicals are generated. As a result, a mass spectrum with high m / z accuracy can be obtained in the radical-induced MS / MS analysis, and the structure of the compound can be analyzed with high accuracy.

[0040] In addition, when multiple types of source gases, such as water vapor, hydrogen gas, and a mixture of water vapor and hydrogen gas, are used in radical-induced MS / MS analysis, or when different gas flow rates can be selected for the same gas type, it is advisable to obtain m / z calibration information for each of the different conditions. This further improves the accuracy of the m / z calibration information, thereby making it possible to further improve the m / z accuracy of the mass spectrum in radical-induced MS / MS analysis.

[0041] An example of an analysis method using the above-mentioned source gas only introduction mode in the mass spectrometer of this embodiment will be described below. Fig. 5 is a control flowchart for performing this analysis.

[0042] For example, when an instruction to start analysis is given through an input unit (not shown), the control unit 3 that receives this instruction sets the raw material gas only introduction mode as the operation mode (step S11). As in step S1, in the raw material gas only introduction mode, the control unit 3 controls the MFCs 262 and 263 so that water vapor, hydrogen gas, or water vapor / hydrogen mixed gas flows into the quartz tube 210 at a predetermined gas flow rate, and stops the operation of the microwave power supply 25. As a result, the raw material gas with an appropriately adjusted flow rate passes through the quartz tube 210 and is introduced directly into the collision cell 132.

[0043] The target sample is electrostatically sprayed from the ESI probe 101 into the ionization chamber 10, and ions generated from the target sample are introduced into the quadrupole mass filter 131 through the ion guides 111 and 121. The control unit 3 operates a power supply (not shown) so that a predetermined voltage is applied to each rod electrode constituting the quadrupole mass filter 131. As a result, only ions having a specific m / z or falling within the m / z range selectively pass through the quadrupole mass filter 131, are guided through the collision cell 132 and the ion transport electrodes 134 and 141 to the orthogonal acceleration unit 142, and are ejected from the orthogonal acceleration unit 142 into the flight space in the flight tube 144 for mass analysis. At this time, the signal obtained by the ion detector 146 is converted into digital data and temporarily stored in the data storage unit 41 (step S12). Since no radicals are introduced into the collision cell 132, no radical-induced dissociation occurs in the collision cell 132.

[0044] Next, the control unit 3 sets the radical introduction mode as the operation mode (step S13). In the radical introduction mode, the control unit 3 controls the MFCs 262 and 263 in the same manner as in the source gas only introduction mode in step S11, while operating the microwave power source 25 to supply microwave power to the helical antenna 211. The microwave frequency can be, for example, 2.5 GHz. The control unit 3 also operates the ultraviolet light source 217 to start emitting deep ultraviolet light to promote plasma lighting. When the microwave power is supplied into the quartz tube 210 via the helical antenna 211, the source gas flowing in the quartz tube 210 is ionized to light the plasma. The radicals generated in this plasma are introduced into the collision cell 132 together with the source gas.

[0045] The target sample, which is the same as the target to be analyzed in step S12, is electrostatically sprayed from the ESI probe 101 into the ionization chamber 10, and ions generated from the target sample are introduced into the quadrupole mass filter 131 through the ion guides 111 and 121. The control unit 3 operates a power supply (not shown) so that a predetermined voltage is applied to each rod electrode constituting the quadrupole mass filter 131. As a result, only ions having a specific m / z or falling within the m / z range selectively pass through the quadrupole mass filter 131 and are introduced into the collision cell 132. At this time, since many radicals are present in the collision cell 132, the ions derived from the target sample undergo radical-induced dissociation, thereby generating various product ions. The product ions are guided to the orthogonal acceleration unit 142 through the ion transport electrodes 134 and 141, and are ejected from the orthogonal acceleration unit 142 into the flight space in the flight tube 144 for mass analysis. The signal obtained by the ion detector 146 at this time is converted into digital data and temporarily stored in the data storage unit 41 (step S14).

[0046] By the processing of steps S11 to S14, the time-of-flight spectrum data in the source gas only introduction mode and the time-of-flight spectrum data in the radical introduction mode for the same target sample are stored in the data storage unit 41. As described above, the time-of-flight spectrum obtained in the radical introduction mode is mass spectrometry data obtained by radical-induced MS / MS analysis. In the radical introduction mode, the source gas is radicalized in the quartz tube 210, but not all molecules contained in the source gas become radicals. In reality, only a part of the molecules in the source gas become radicals, and the remaining molecules are introduced as they are into the collision cell 132. Since water vapor and hydrogen gas are more active than inert gases such as argon used as a CID gas, depending on the type of sample, ions derived from the sample and the source gas itself may react in the collision cell 132 to generate other ions. Therefore, the peaks due to the ions generated in this way may appear in the mass spectrum together with the product ion peaks due to radical-induced dissociation, in which case it is difficult to interpret the mass spectrum.

[0047] In contrast, the time-of-flight spectrum obtained under the source gas only introduction mode has peaks corresponding to ions generated by the reaction of ions derived from the sample with the source gas itself in the collision cell 132, but does not have product ion peaks due to radical induced dissociation. Therefore, by comparing the time-of-flight spectrum obtained under the radical introduction mode with the time-of-flight spectrum obtained under the source gas only introduction mode, it is possible to easily distinguish between peaks due to ions generated by the reaction of ions derived from the sample with the source gas itself and product ion peaks due to radical induced dissociation. Therefore, here, the m / z calibration unit 44 first uses the m / z calibration information stored in the m / z calibration information storage unit 43 to obtain mass spectra from both time-of-flight spectra (step S15).

[0048] The data analysis unit 45 compares the two mass spectra to identify peaks corresponding to ions generated by the reaction of ions derived from the sample and the raw material gas itself that are not necessary for structural analysis, and creates a processed mass spectrum from which the peaks are deleted, in which product ion peaks due to radical-induced dissociation mainly appear (step S16).Furthermore, the structure of the compound in the target sample is estimated based on the m / z values ​​of the peaks observed in the processed mass spectrum (step S17).

[0049] In this way, during radical-induced MS / MS analysis, the influence of ions generated by the reaction between ions derived from the sample and the source gas itself can be eliminated, enabling highly accurate structural analysis. Before converting the time-of-flight spectrum to a mass spectrum in step S15, it is also possible to distinguish between product ion peaks due to radical-induced dissociation and peaks of ions generated by reaction of ions derived from the sample with the raw material gas itself at the time-of-flight spectrum stage, obtain a time-of-flight spectrum excluding the latter peaks, and obtain a mass spectrum from the time-of-flight spectrum.

[0050] In the mass spectrometer of this embodiment, the source gas used is water vapor volatilized from water stored in the water storage unit 264 and hydrogen supplied from a hydrogen cylinder 265 (or a hydrogen generator) attached to the end of the hydrogen supply pipe 261. When this mass spectrometer is not used for a long period of time or when the inside of the vacuum chamber 1 of the apparatus is opened to the atmosphere, air (outside air) may get into the piping through minute openings in the MFCs 262, 263, the water storage unit 264, the hydrogen supply pipe 261, and the water vapor supply pipe 260. Of course, air also gets into the piping when the piping is reconnected.

[0051] The inside of the pipe downstream of the MFCs 262 and 263 (on the plasma generating unit 21 side) is evacuated by a pump that evacuates the vacuum chamber 1. On the other hand, the air accumulated inside the pipe upstream of the MFCs 262 and 263 (hydrogen supply pipe 261, water vapor supply pipe 260) is not discharged to the outside unless the MFCs 262 and 263 are opened. If high-frequency discharge is performed to generate radicals in a state where air is mixed in the raw material gas, radicals of various gas species present in the air are generated, and members disposed inside the vacuum chamber 1 may be contaminated. Therefore, it is desirable that the raw material gas is not mixed with air at the time when the generation of radicals by the raw material gas is started. In response to this, the mass spectrometer of this embodiment has a pipe gas venting mode as one of the operation modes for forcibly venting the air accumulated in the hydrogen supply pipe 261 and the water vapor supply pipe 260.

[0052] The piping degassing mode is a mode in which gas remaining in the water storage section 264, the water vapor supply pipe 260, and the hydrogen supply pipe 261 upstream of the MFCs 262 and 263 is caused to flow to the vacuum side, thereby removing the remaining gas. Fig. 6 is a control flowchart of the piping degassing mode in the mass spectrometer of this embodiment.

[0053] Before implementing the piping gas removal mode, the user closes the manual opening and closing valve 266 to cut off the supply of hydrogen gas to the hydrogen supply pipe 261. However, this operation is not essential, and consideration is also given to the case where this operation is not performed, as described below. For example, when an instruction to execute a piping gas degassing operation is given through an input unit (not shown), the control unit 3 receiving this instruction sets the piping gas degassing mode as the operation mode (step S21).

[0054] When the piping degassing mode is started, the control unit 3 first detects the degree of vacuum, for example, in the first analysis chamber 13 using a vacuum gauge (not shown) and judges whether the degree of vacuum is equal to or lower than a predetermined value (step S22). If the degree of vacuum exceeds the predetermined value (i.e., if the degree of vacuum is poor), there is a concern that a breakdown may occur due to discharge between electrodes if the gas in the piping is caused to flow into the vacuum chamber 1 and the degree of vacuum in the vacuum chamber 1 further deteriorates. For this reason, the vacuum degree in the vacuum chamber 1 is checked before piping degassing is performed, and if the degree of vacuum exceeds the predetermined value (No in step S22), it is judged that there is a vacuum abnormality. In this case, the control unit 3 displays on the display unit (not shown) that the piping degassing mode cannot be executed due to a low degree of vacuum (step S29), and ends the process.

[0055] On the other hand, if the degree of vacuum is equal to or lower than the predetermined value, the control unit 3 executes degassing of the water vapor pipe (step S23). Specifically, the following process is executed.

[0056] The water storage section 264 usually stores water, and water vapor generated by evaporation from the stored water is used as a raw gas for radical generation. When the amount of stored water decreases, the volume of the upper space (space above the water surface) in the water storage section 264 increases accordingly, and the maximum amount of air that can flow therein increases. Therefore, the control section 3 calculates the maximum amount of air (amount of remaining gas) that can flow into the piping upstream of the first MFC 262, including the water storage section 264, based on the volumes of the water storage section 264 and the piping of the water vapor supply pipe 260 between the water storage section 264 and the first MFC 262 (these are known fixed values), and the initial amount of water stored in the water storage section 264. The initial amount of water stored in the water storage section 264 can be estimated, for example, as water stored up to the position of an initial water level mark provided in the water storage section 264. Then, based on the amount of remaining gas and the set value of the gas flow rate through first MFC 262, the time required to flush out the remaining gas is calculated, and gas is allowed to flow downstream through first MFC 262 until at least this time has elapsed, that is, until the total amount of gas flowing through first MFC 262 is equal to or greater than the remaining gas amount (step S24). This makes it possible to create a state in which no air is present in the piping of water storage section 264, etc.

[0057] Furthermore, when the air is completely removed from the piping including the water storage portion 264, the pressure in the water storage portion 264 becomes the saturated vapor pressure. Therefore, instead of determining the end time of degassing from the amount of remaining gas calculated as described above, a pressure gauge that measures the gas pressure in the upper space of the water storage portion 264 and a temperature sensor that measures the temperature may be installed, and it may be determined whether degassing of the water storage portion 264 is complete or not based on the measured pressure and the theoretical saturated vapor pressure at the temperature at that time. Also, in order to calculate the amount of remaining gas, a water level sensor that can detect the level of water remaining in the water storage portion 264 may be attached.

[0058] When the degassing in the water vapor pipe is completed by steps S23 and S24, the control unit 3 then executes degassing of the hydrogen gas pipe (step S25). Since the supply of hydrogen gas is cut off as described above, when the gas (air and hydrogen gas) in the hydrogen supply pipe 261 upstream of the second MFC 263 decreases, the gas pressure in the pipe decreases. This makes it impossible to flow gas through the second MFC 263. Therefore, the control unit 3 can determine whether degassing of the hydrogen gas pipe is completed based on the flow rate of the gas actually flowing, which can be monitored by the second MFC 263. That is, the control unit 3 continuously monitors this gas flow rate, and when the flow rate becomes equivalent to zero (Yes in step S26), determines that degassing is completed.

[0059] Since the length and diameter of the hydrogen supply pipe 261 can be changed by the user as appropriate, the maximum amount of air flowing into the pipe is not fixed. However, by determining whether degassing is completed as described above, the entire amount of air can be reliably degassed regardless of the maximum amount of air flowing into the pipe. However, there is a possibility that hydrogen gas continues to be supplied because the user forgets to close the manual opening and closing valve 266, and therefore the determination in step S26 continues to be No. Therefore, even if the determination in step S26 is No, when the total amount of gas flowing through the second MFC 263 reaches a predetermined remaining gas amount (Yes in step S27), the control unit 3 determines that degassing has been forcibly completed, and completes a series of degassing processes (step S28). The remaining gas amount at this time can be a value that is predetermined based on the maximum length and maximum diameter of the hydrogen gas pipe that is generally used (or recommended by the device manufacturer).

[0060] As described above, by performing the piping degassing mode prior to performing radical-induced MS / MS analysis, gas is vented from both the water vapor piping and the hydrogen gas piping, and a state in which no air remains in either piping can be achieved. As described above, if microwave power is supplied to generate radicals and discharge is performed in a state in which air (outside air) is mixed into water vapor or hydrogen gas, problems such as contamination of the inside of the device or failure to obtain appropriate measurement data can occur. By performing the piping degassing mode, on the other hand, it is possible to prevent such problems from occurring.

[0061] In general, the gas flow rate of the MFCs 262, 263 during degassing should be approximately the same as that during radical-induced MS / MS analysis so as not to deteriorate the degree of vacuum in the vacuum chamber 1, but if there is little concern about deterioration of the degree of vacuum, such as when the vacuum exhaust capacity is very high, the gas flow rate may be greater than that during radical-induced MS / MS analysis. This makes it possible to shorten the time required for degassing the piping.

[0062] In order to more reliably prevent contamination of the device, it is preferable to always degas the piping including the water storage section 264 assuming the maximum remaining gas amount, but this increases the time required for degassing, hindering efficient analysis. Therefore, for example, degassing assuming the maximum remaining gas amount may be performed only immediately after detecting that the gas piping is open to the atmosphere, such as when pouring water into the water storage section 264, and at other times, degassing a predetermined fixed amount may be performed without calculating the remaining gas amount. In addition, the amount of air that leaks into the device when it is not in use (when evacuation is not being performed) may be estimated in advance, and the amount of remaining gas may be estimated based on this estimated value and the time the device has not been used.

[0063] In the above description, in the piping degassing mode, degassing of the water vapor piping including the water storage section 264 and degassing of the hydrogen gas piping are performed in sequence, but these may be performed independently. In other words, only one of the degassing operations may be selectively performed depending on a button operation or the like. This makes it possible to perform only the degassing of the hydrogen gas piping when, for example, the user changes or reconnects the hydrogen gas piping, thereby avoiding unnecessary degassing and improving the efficiency of the analysis work.

[0064] In the mass spectrometer of the above embodiment, water vapor and hydrogen gas are used as the source gas for radicals, but it can be easily conceived that the present invention can be applied even when other gas species such as nitrogen are used as the source gas.

[0065] In addition, the above embodiment is an example in which the ion analyzer according to the present invention is applied to a Q-TOF mass analyzer, but it is clear that the present invention is not limited to the Q-TOF type. Specifically, the present invention can also be applied to other types of mass analyzers that dissociate ions and perform mass analysis, such as a triple quadrupole mass analyzer, an ion trap mass analyzer, and an ion trap time-of-flight mass analyzer.

[0066] The present invention can also be applied to devices in general that dissociate ions using radicals generated in plasma and analyze the product ions generated by the dissociation. Specifically, the present invention can also be applied to, for example, an ion mobility analyzer that separates and detects ions according to their ion mobility, or an ion mobility-mass analyzer that separates ions using both their ion mobility and m / z.

[0067] The above-mentioned configuration of the mass spectrometer, particularly the configuration of the radical generating unit 2 that generates radicals, is merely an example, and it goes without saying that it can be modified as appropriate as long as it is a configuration that can generate radicals by plasma. The radicals referred to here include hydroxyl radicals, hydrogen radicals, oxygen radicals, nitrogen radicals, etc. that are generally used in radical induced dissociation methods, as well as various molecules and atoms that are in an excited state or in a metastable state when energy is given to them.

[0068] Furthermore, the above-described embodiment and the various modified examples are merely examples of the present invention, and it is clear that any appropriate modifications, additions, etc. made within the spirit of the present invention will also be encompassed within the scope of the claims of the present application.

[0069] [Various aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0070] (Item 1) One aspect of the ion analyzer according to the present invention is an ion analyzer that brings radicals into contact with ions derived from a sample in a reaction chamber to dissociate the ions, a generation chamber into which a source gas serving as a radical is introduced; A power supply unit that supplies power to generate a discharge inside the generation chamber; a raw material gas supply unit that supplies the raw material gas to the reaction chamber through the generation chamber; a control unit for controlling the raw material gas supply unit and the power supply unit, switchably implementing a radical generation mode in which the raw material gas is caused to flow into the generation chamber and power is supplied to the generation chamber, and a raw material gas only introduction mode in which the raw material gas is caused to flow into the generation chamber and power is not supplied to the generation chamber; Equipped with.

[0071] (Item 6) One aspect of the ion analysis method according to the present invention is an ion analysis method comprising: introducing radicals generated in a generation chamber into a reaction chamber; and contacting the radicals with ions derived from a sample in the reaction chamber to dissociate the ions, a first step of supplying a source gas that is a source of radicals to the reaction chamber through the generation chamber and supplying power to the generation chamber for generating a discharge, thereby performing an analysis in a state in which the source gas can be radicalized; a second step of supplying the source gas to the reaction chamber through the generation chamber and not supplying the power to the generation chamber, thereby performing an analysis in a state in which the source gas cannot be radicalized; has.

[0072] In the ion analyzer described in paragraph 1 and the ion analysis method described in paragraph 6, it is possible to selectively carry out an operation mode in which radicals are not generated in the generation chamber and the raw material gas is introduced directly into the reaction chamber. This makes it possible to obtain mass spectrometry data in a state in which the ions derived from the sample can react with particles (molecules) in the raw material gas without causing radical-induced dissociation of the ions, which could not be obtained with this type of conventional ion analyzer. Therefore, according to the ion analyzer described in paragraph 1 and the ion analysis method described in paragraph 6, for example, based on both mass spectrometry data in a state in which radical-induced dissociation does not occur and mass spectrometry data obtained by radical-induced MS / MS analysis for the same sample, it is possible to accurately distinguish between ions generated by the reaction between ions derived from the sample and components in the raw material gas and ions generated by the reaction between ions derived from the sample and radicals, and to easily and accurately perform structural analysis of compounds in the sample.

[0073] According to the ion analyzer described in paragraph 1 and the ion analysis method described in paragraph 6, while introducing the source gas into the reaction chamber in a manner similar to that during radical generation, that is, under conditions in which the source gas is present in the reaction chamber, mass analysis can be performed on an appropriate standard sample for mass calibration, and mass analysis data for the standard sample can be obtained. Based on this mass analysis data, highly accurate mass calibration information that can be used during radical-induced MS / MS analysis can be obtained, and a highly accurate mass spectrum can be created from the mass analysis data obtained by the radical-induced MS / MS analysis.

[0074] (Item 2) The ion analysis device described in item 1 may further include an analysis unit that performs analysis of compounds in the sample based on mass analysis data acquired in the radical generation mode and mass analysis data acquired in the source gas only introduction mode for the same sample.

[0075] (Item 7) The ion analysis method described in Item 6 may further include an analysis step of analyzing compounds in the same sample based on the mass analysis data acquired in the first step and the mass analysis data acquired in the second step.

[0076] According to the ion analyzer described in item 2 and the ion analysis method described in item 7, it is possible to accurately identify product ions generated by reaction with radicals from a mass spectrum acquired by radical-induced MS / MS analysis, by excluding peaks of ions unnecessary for (interfering with) analysis, which are generated by reaction between ions derived from the sample and components in the source gas. This makes it possible to easily and accurately perform structural analysis of compounds in a sample.

[0077] (Item 3) The ion analysis device described in item 1 or 2 may further include a calibration information calculation unit that calculates mass calibration information for a predetermined sample based on mass analysis data acquired in the source gas only introduction mode.

[0078] (Item 4) The ion analysis device described in item 3 may further include a calibration unit that uses the mass calibration information to calibrate mass information in mass analysis data acquired under the source gas only introduction mode.

[0079] (Item 8) The ion analysis method described in Item 6 or Item 7 may further include a calibration information calculation step of calculating mass calibration information for a specified sample based on the mass analysis data acquired in the second step.

[0080] (Item 9) The ion analysis method described in Item 8 may further include a calibration execution step of calibrating mass information in the mass analysis data acquired in the first step using the mass calibration information.

[0081] In the ion analyzer described in paragraphs 3 and 4 and the ion analysis method described in paragraphs 8 and 9, mass calibration information can be obtained using a standard sample in a state where a raw material gas is introduced into the reaction chamber in a manner similar to that when radicals are generated. This allows a sample that may cause radical-induced dissociation to be used as a standard sample. In addition, mass calibration information is obtained in a state where a raw material gas is introduced into the reaction chamber, not in a state where argon or the like used as a CID gas or a cooling gas is introduced into the reaction chamber, so that the mass calibration information almost reflects the mass shift of the mass analysis data obtained by radical-induced MS / MS analysis. Therefore, a mass spectrum with high mass accuracy can be created, and the accuracy of structural analysis based on this mass spectrum can be improved.

[0082] (Item 5) In the ion analyzer according to any one of items 1 to 4, the raw material gas supply unit includes a gas adjustment unit that adjusts a flow rate of the raw material gas flowing through a gas flow passage connected to the generation chamber or allows / stops the flow of the raw material gas to the flow passage, The control unit may control the gas adjusting unit to implement a piping gas venting mode in which the gas adjusting unit allows a source gas to flow through the gas flow passage until a predetermined condition is satisfied.

[0083] In the ion analyzer described in paragraph 5, by implementing a piping degassing mode prior to performing radical-induced MS / MS analysis, undesired gas remaining in the piping, for example, air (outside air), can be removed from the piping. If radicals are generated while air containing various impurities remains in the piping, radicals derived from such impurities may be introduced into the device and cause contamination of electrodes, etc. In contrast, the ion analyzer described in paragraph 5 can prevent radicals derived from impurities from being introduced into the device, reducing the time wasted on cleaning the device, and collecting good measurement data with no or little contamination of electrodes, etc. [Explanation of symbols]

[0084] 1. Vacuum chamber 10…Ionization chamber 11…First intermediate vacuum chamber 12...Second intermediate vacuum chamber 13…1st analysis room 14…Second analysis room 101…ESI probe 102...solvent removal tube 111, 121…Ion Guide 112…Skimmer 131...Quadrupole mass filter 132…Collision cell 1320…Aperture 1321...Pipe connection parts 133...Multipole ion guide 134, 141...Ion transport electrodes 135…CID gas supply unit 136…CID gas supply pipe 137…Gas valve 142...Orthogonal acceleration section 143...acceleration electrode 144…Flight tube 145...Reflectron electrode 146...Ion detector 2... Radical generation section 21...Plasma generating section 210...Quartz tube 211…Helical antenna 212...Outer conductor part 213...Permanent magnet 214…Casing 215...Permanent magnet 216...Microwave supply connector 217...Ultraviolet light source 218...Photodetector 220...Resonator adjustment mechanism 221...Magnet holder 222... Retaining member 25...Microwave power supply 26…Source gas supply source 260…Steam supply pipe 261...Hydrogen supply pipe 262, 263...Mass flow controller (MFC) 264...Water storage section 265…Hydrogen cylinder 266...Manual opening and closing valve 3. Control section 4. Data processing section 41...Data storage section 42...m / z calibration information calculation section 43...m / z calibration information storage section 44...m / z calibration section 45…Data Analysis Section C…Ion optical axis

Claims

1. An ion analyzer that dissociates ions derived from a sample by bringing radicals into contact with the ions in a reaction chamber, a generation chamber into which a source gas serving as a radical is introduced; A power supply unit that supplies power to generate a discharge inside the generation chamber; a raw material gas supply unit that supplies the raw material gas to the reaction chamber through the generation chamber; a control unit for controlling the raw material gas supply unit and the power supply unit, switchably implementing a radical generation mode in which the raw material gas is caused to flow into the generation chamber and power is supplied to the generation chamber, and a raw material gas only introduction mode in which the raw material gas is caused to flow into the generation chamber and power is not supplied to the generation chamber; An ion analyzer comprising:

2. an analysis unit that performs analysis of compounds in the same sample based on mass spectrometry data acquired in the radical generation mode and mass spectrometry data acquired in the source gas only introduction mode; The ion analyzing device of claim 1 further comprising:

3. 2. The ion analyzer according to claim 1, further comprising a calibration information calculation unit that calculates mass calibration information for a predetermined sample based on mass analysis data acquired in the source gas only introduction mode.

4. The ion analyzer according to claim 3 , further comprising a calibration unit that uses the mass calibration information to calibrate mass information in mass analysis data acquired in the source gas only introduction mode.

5. the raw material gas supply unit includes a gas adjustment unit that adjusts a flow rate of the raw material gas flowing through a gas flow passage connected to the generation chamber or allows / stops the flow of the raw material gas to the flow passage; The ion analyzer according to claim 1 , wherein the control unit controls the gas regulator to implement a piping gas venting mode in which the gas regulator causes the source gas to flow through the gas flow passage until a predetermined condition is satisfied.

6. 1. An ion analysis method comprising: introducing radicals generated in a generation chamber into a reaction chamber; and contacting the radicals with ions derived from a sample in the reaction chamber to dissociate the ions, a first step of supplying a source gas that is a source of radicals to the reaction chamber through the generation chamber and supplying power to the generation chamber for generating a discharge, thereby performing an analysis in a state in which the source gas can be converted into radicals; a second step of supplying the source gas to the reaction chamber through the generation chamber and not supplying the power to the generation chamber, thereby performing an analysis in a state in which the source gas cannot be radicalized; The ion analysis method according to claim 1,

7. an analysis step of analyzing compounds in the same sample based on the mass spectrometry data acquired in the first step and the mass spectrometry data acquired in the second step; The ion analysis method according to claim 6 , further comprising:

8. 7. The ion analysis method according to claim 6, further comprising a calibration information calculation step of calculating mass calibration information for a predetermined sample based on the mass analysis data acquired in the second step.

9. The ion analysis method according to claim 8 , further comprising a calibration execution step of calibrating mass information in the mass analysis data acquired in the first step by using the mass calibration information.

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