Mass spectrometer and method for controlling mass spectrometer

Abstract

A mass spectrometer (100) comprises an ionization chamber (200), ion guides (23, 25), a detector (28), and a control device (3). The control device is configured to execute a determination process. The determination process includes: a process of measuring a first ion intensity; a process of measuring a second ion intensity when a first period has elapsed after the measurement of the first ion intensity; a process in which the polarity mode is switched from a first polarity mode to a second polarity mode after the measurement of the second ion intensity, the polarity mode is returned to the first polarity mode when a second period shorter than the first period has elapsed, and a third ion intensity is measured; and a process of outputting a display signal for displaying, to a user, a determination result that the degree of contamination of the ion guides satisfies a contamination criterion.

Description

Mass spectrometer and method for controlling a mass spectrometer

[0001] The present disclosure relates to mass spectrometers and methods for controlling mass spectrometers.

[0002] A known example of a mass analyzer is a high-performance liquid chromatograph mass spectrometer (LC-MS). In this type of mass analyzer, a sample ionized under atmospheric pressure is introduced into a vacuum chamber and transported to a mass separator (e.g., quadrupole rods) in a high vacuum section using multiple ion guides. The mass separator separates ions according to their mass-to-charge ratio (m / z). The ions separated by the mass separator are detected by a detector.

[0003] As the accumulation time of mass analysis increases, the ion guide and mass separator become contaminated with impurities and unwanted ions. When the ion guide and mass separator become contaminated, the ion intensity decreases, thereby degrading the performance of the mass analyzer. To prevent this degradation of the mass analyzer performance, the ion guide and mass separator must be cleaned (such as by abrasive cleaning or ultrasonic cleaning) from time to time.

[0004] U.S. Patent Application Publication No. 2014 / 0264007 (Patent Document 1) and International Publication No. 2019 / 229954 (Patent Document 2) disclose a method for identifying charge-up locations by alternately flowing ions with reversed polarity and checking the amount of recovery of signal intensity.

[0005] US Patent Application Publication No. 2014 / 0264007 International Publication No. 2019 / 229954

[0006] Ion guides are installed in mass spectrometers so that they can be easily attached and detached. This allows users to easily remove the ion guide from the mass spectrometer and clean it. In contrast, mass separators are precision components, so removing them from the mass spectrometer and cleaning them requires a certain level of skill. This means that users cannot handle mass separators like ion guides and must ask a field engineer to clean them.

[0007] Therefore, the user needs to determine whether the state of the mass spectrometer is one in which both the ion guide and the mass separator are highly contaminated, or one in which the ion guide is highly contaminated but the mass separator is not, but until now, there has been no method to assist in such a determination.

[0008] The present disclosure has been made to solve such problems, and aims to provide users with the information necessary to determine the degree of contamination of ion guides and mass separators.

[0009] The present disclosure provides a mass spectrometer equipped with a mass separator, the mass spectrometer comprising an ionization chamber for ionizing sample components, an ion guide for guiding ions generated in the ionization chamber to the mass separator, a detector for detecting ions separated by the mass separator, and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, wherein the control device is configured to execute a determination process for determining a contamination status of the mass spectrometer by switching polarity modes between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, the determination process including a process for measuring a first ion intensity of the sample components in the first polarity mode, and a process for measuring a first ion intensity of the sample components in the first polarity mode after measuring the first ion intensity. the second ion intensity of the sample component in the first polarity mode after a certain period has elapsed; switching the polarity mode from the first polarity mode to the second polarity mode after measuring the second ion intensity, and returning the polarity mode to the first polarity mode after a second period shorter than the first period has elapsed, and measuring a third ion intensity of the sample component in the first polarity mode; and determining that the degree of contamination of the ion guide, of the ion guide and the mass separator, satisfies the contamination standard if the second ion intensity is smaller than the intensity corresponding to a first reference proportion of the first ion intensity and the third ion intensity is greater than the intensity corresponding to a second reference proportion of the first ion intensity, and outputting a display signal to display the determination result to a user.

[0010] The present disclosure relates to a method for controlling a mass spectrometer equipped with a mass separator, the method being realized by a processor executing a program stored in a memory, the mass spectrometer comprising an ionization chamber for ionizing sample components, an ion guide for guiding ions generated in the ionization chamber to the mass separator, a detector for detecting ions separated by the mass separator, and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, the control device being configured to execute a determination process for determining the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, the method including, as a step related to the determination process, measuring a first ion intensity of the sample components in the first polarity mode. the step of measuring a second ion intensity of the sample component in the first polarity mode when a first period in the first polarity mode has elapsed after measuring the first ion intensity; the step of switching the polarity mode from the first polarity mode to the second polarity mode after measuring the second ion intensity, and returning the polarity mode to the first polarity mode when a second period shorter than the first period has elapsed, and measuring a third ion intensity of the sample component in the first polarity mode; and the step of determining that the degree of contamination of the ion guide, of the ion guide and the mass separator, satisfies the contamination standard when the second ion intensity is smaller than the intensity corresponding to a first reference proportion of the first ion intensity and the third ion intensity is greater than the intensity corresponding to a second reference proportion of the first ion intensity, and outputting a display signal to display the determination result to a user.

[0011] The present disclosure provides a mass spectrometer equipped with a mass separator, the mass spectrometer comprising: an ionization chamber for ionizing sample components; an ion guide for guiding ions generated in the ionization chamber to the mass separator; a detector for detecting ions separated by the mass separator; and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, wherein the control device is configured to execute a determination process for determining a contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, and the determination process is performed after an initialization period has elapsed since the polarity mode was switched from the first polarity mode to the second polarity mode. The method includes a process of returning the polarity mode to the first polarity mode, a process of measuring a second ion intensity of the sample component in the first polarity mode when a first period in the first polarity mode has elapsed after the polarity mode has been returned to the first polarity mode, a process of switching the polarity mode from the first polarity mode to the second polarity mode after measuring the second ion intensity, and a process of returning the polarity mode to the first polarity mode when a second period shorter than the first period has elapsed, and a process of measuring a third ion intensity of the sample component in the first polarity mode, and a process of determining that the degree of contamination of the ion guide satisfies the contamination criterion if the third ion intensity is greater than the second ion intensity, and outputting a display signal to display the determination result to a user.

[0012] The present disclosure provides users with the information necessary to determine the extent of contamination in ion guides and mass separators.

[0013] FIG. 1 is a schematic diagram of a mass spectrometer according to the present embodiment; FIG. 2 is a diagram showing an example of ion intensity transition in a normal case; FIG. 3 is a diagram showing an example of ion intensity transition when an ion guide is contaminated; FIG. 4 is a diagram showing an example of ion intensity transition when a quadrupole rod is contaminated; FIG. 5 is a timing chart and a flowchart showing a process for determining parts that require cleaning; FIG. 6 is a flowchart for explaining a determination process for determining parts that require cleaning; FIG. 7 is a flowchart for explaining a determination process for determining parts that require cleaning; FIG. 8 is a diagram showing an example of a screen showing test results of the determination process; and FIG. 9 is a diagram showing a modified example related to the determination process for determining parts that require cleaning.

[0014] Hereinafter, embodiments will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0015] [Overall Configuration of Mass Spectrometer] Fig. 1 is a schematic diagram of a mass spectrometer 100 according to this embodiment. Here, the mass spectrometer 100 is a triple quadrupole (TQ) mass spectrometer. In the following, this embodiment will be described using a triple quadrupole mass spectrometer as an example of a mass spectrometer.

[0016] However, the mass spectrometer according to the present disclosure is not limited to a triple quadrupole mass spectrometer, and may be, for example, a hybrid mass spectrometer such as a Q-TOF mass spectrometer (QQ type), a Q-ion cyclotron resonance (ICR) type, or a Q-Fourier transform type.

[0017] The mass spectrometer 100 includes a housing 2 , a control device 3 , a power supply circuit 4 , a rotary pump 5 , and a turbomolecular pump 6 .

[0018] A plurality of spaces are formed inside the housing 2. The plurality of spaces include an ionization chamber 200, intermediate chambers 201 to 203, and an analysis chamber 204. The intermediate chambers 201 to 203 and the analysis chamber 204 are evacuated by vacuum pumps (a rotary pump 5 and a turbomolecular pump 212) so that the degree of vacuum increases in the order of intermediate chamber 201, intermediate chamber 202, intermediate chamber 203, and analysis chamber 204. More specifically, the intermediate chamber 201 is evacuated by the rotary pump 5, and the intermediate chambers 202, 203, and analysis chamber 204 are evacuated by the rotary pump 5 and the turbomolecular pump 6.

[0019] The housing 2 is equipped with various components for ionizing a sample, separating the ions according to their mass-to-charge ratios, and measuring each ion. An electrospray ionization (ESI) source 21 is provided in the ionization chamber 200. The electrospray ionization source 21 has the function of ionizing a liquid sample. An eluate, which is an example of a liquid sample, is continuously introduced into the electrospray ion source 21 from, for example, a liquid chromatograph. The electrospray ion source 21 sprays the liquid sample into the ionization chamber 200 while imparting an electric charge to the liquid sample. As a result, compounds in the liquid sample are ionized in the ionization chamber 200.

[0020] The method for ionizing compounds is not limited to this, and other ion sources, such as an atmospheric pressure chemical ion source, may be used. An ion source that ionizes a gaseous sample or a solid sample, rather than a liquid sample, may also be used. A liquid sample may be continuously introduced into the ESI source 21 by flow injection analysis. A sample may be intermittently introduced into the electrospray ion source 21.

[0021] The ionization chamber 200 and the intermediate chamber 201 are connected by a desolvation tube 22. Ions derived from sample components and fine charged droplets generated in the ionization chamber 200 are sent to the intermediate chamber 201 via the desolvation tube 22 mainly due to the pressure difference between the ionization chamber 200 and the intermediate chamber 201. The desolvation tube 22 is, for example, a heated capillary. When the charged droplets pass through the inside of the desolvation tube 22, evaporation of the solvent in the droplets progresses, promoting the generation of ions.

[0022] A multipole ion guide 23 is arranged in the intermediate chamber 201, and multipole ion guides 25 are arranged in the intermediate chambers 202 and 203. Two sets of quadrupole rods 26 and a detector 28 are arranged in the analysis chamber 204. A reaction chamber 27 is formed between the two sets of quadrupole rods 26. The quadrupole rods 26 shown in FIG. 1 are configured to include pre-rods and post-rods. The quadrupole rods 26 are an example of a mass separator configured with multiple rod electrodes.

[0023] The ion guides 23, 25 and the quadrupole rods 26 are examples of electrodes. The power supply circuit 4 applies voltage to the ion guides 23, 25 and the quadrupole rods 26. The control device 3 adjusts the electric field in the ion guides 23, 25 and the quadrupole rods 26 by controlling the power supply circuit 4. The ion guides 23, 25 are composed of multiple electrodes arranged to surround the ion optical axis C1, and the multiple electrodes form an ion passage space through which the ions travel. The ion guides 23, 25 guide the ions generated in the ionization chamber 200 toward the quadrupole rods 26 using the polarity of the ions.

[0024] The ions sent into the intermediate chamber 201 are focused by the ion guide 23 to the vicinity of the ion optical axis C 1 , and then guided into the intermediate chamber 202 through an opening at the top of the skimmer 24 .

[0025] The ions guided to the intermediate chamber 202 are focused by the ion guide 25 to the vicinity of the ion optical axis C1, and are guided from the intermediate chamber 202 to the intermediate chamber 203. The ions guided to the intermediate chamber 203 are focused by the ion guide 25 to the vicinity of the ion optical axis C1, and are guided from the intermediate chamber 203 to the analysis chamber 204. A quadrupole rod 26 is arranged in the analysis chamber 204.

[0026] The quadrupole rods 26 have the function of separating ions according to their mass-to-charge ratio. The quadrupole rods 26 separate the ions guided to the analysis chamber 204 and select specific ions. Of the two sets of quadrupole rods 26, the ions selected by the quadrupole rod 26 located closer to the intermediate chamber 203 (hereinafter referred to as precursor ions) are guided to the reaction chamber 27.

[0027] A gas is introduced into the reaction chamber 27 to cause fragmentation of precursor ions. When the precursor ions collide with gas molecules, they are dissociated by collision-induced dissociation (CID). This generates product ions. The product ions are guided to the quadrupole rods 26, which are arranged between the reaction chamber 27 and a detector 28. The ions selected by the quadrupole rods 26 are detected by the detector 28.

[0028] The control device 3 controls the mass spectrometer 100. The control device 3 controls various components arranged in the housing 2, the power supply circuit 4, the rotary pump 5, and the turbomolecular pump 6. The control device 3 measures the ion intensity based on the detection value (ion intensity signal) of the detector 28.

[0029] The control device 3 includes a processor 31, a memory 32, an input / output interface 33, a display device 34, and an input device 35. The control device 3 is typically a computer.

[0030] The processor 31 is typically an arithmetic processing unit such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The processor 31 controls the operation of the control device 3 by reading and executing programs stored in the memory 32.

[0031] The memory 32 is realized by a storage device such as a read-only memory (ROM), a random access memory (RAM), and a hard disk drive (HDD). The ROM can store programs executed by the processor 31. The RAM is configured to temporarily store data used while the processor 31 is executing the programs. The RAM functions as a temporary data memory used as a working area. The HDD is a non-volatile storage device. A semiconductor storage device such as a flash memory may be used in addition to or instead of the HDD. The programs and / or data may be stored in an external storage device accessible by the processor 31.

[0032] The input / output interface 33 is an interface for exchanging various types of data between the processor 31 and external devices connected to the input / output interface 33. The external devices include a display device 34, an input device 35, components arranged inside the housing 2, and a power supply circuit 4. The display device 34 displays, for example, the processing results of the processor 31. The input device 35 is typically composed of a touch panel, a keyboard, a mouse, etc. The input device 35 accepts input operations from the user.

[0033] The power supply circuit 4 applies voltages to the ion guides 23, 25 and the quadrupole rods 26 in accordance with commands from the control device 3. When performing mass analysis on positive ions, the power supply circuit 4 applies voltages to the ion guides 23, 25 and the quadrupole rods 26 such that positive ions can be transported. In this case, the positive ions generated in the ionization chamber 200 are guided to the detector 28 along the ion optical axis C1. When performing mass analysis on negative ions, the power supply circuit 4 applies voltages to the ion guides 23, 25 and the quadrupole rods 26 such that negative ions can be transported. In this case, the negative ions generated in the ionization chamber 200 are guided to the detector 28 along the ion optical axis C1.

[0034] Hereinafter, the polarity mode for performing mass analysis on positive ions may be referred to as the “positive mode,” and the polarity mode for performing mass analysis on negative ions may be referred to as the “negative mode.” The control device 3 controls the power supply circuit 4 to switch the polarity mode between the positive mode and the negative mode.

[0035] [Problem of Contamination of the Ion Guides 23, 25 and the Quadrupole Rods 26] As the accumulation time of mass analysis increases, the ion guides 23, 25 and the quadrupole rods 26 become contaminated by impurities and unwanted ions. Contamination of the ion guides 23, 25 and the quadrupole rods 26 disrupts the electric field formed in the intermediate chambers 201-203 and the analysis chamber 204. For example, when mass analysis is performed continuously in positive mode, positive ions gradually accumulate on the surfaces of the electrodes formed by the ion guides 23, 25 and the quadrupole rods 26, causing "charge-up." This charge-up causes positive charges to predominate, disrupting the electric field. As a result, the ion transport efficiency decreases, and the sensitivity of the mass analyzer 100 decreases. In such cases, the polarity of the electrode surfaces is neutralized by switching the polarity mode from positive mode to negative mode and allowing negative ions to flow through the mass analyzer 100, temporarily restoring the sensitivity of the mass analyzer 100.

[0036] Therefore, in the past, when the sensitivity of the mass spectrometer 100 decreased, the user would take advantage of this phenomenon and perform maintenance work to restore the sensitivity of the mass spectrometer 100. That is, when the sensitivity of the mass spectrometer 100 decreased, the user would switch the polarity mode to a mode with the opposite polarity to the polarity mode used during mass analysis, and cause ions of the opposite polarity to the charged-up polarity to flow through the mass spectrometer 100. After completing this maintenance work, the user would return the polarity of the polarity mode to its original state and resume mass analysis.

[0037] However, as the sensitivity repeatedly decreases and temporarily recovers, the time during which the sensitivity is temporarily recovered becomes shorter, which requires the user to occasionally clean the ion guides 23 and 25 and the quadrupole rods 26.

[0038] The ion guides 23, 25 are arranged in the mass spectrometer 100 so as to be easily detachable. This allows the user to easily remove the ion guides 23, 25 from the mass spectrometer 100 and clean them. In contrast, the quadrupole rods 26 are precision components, and therefore require a certain level of skill to remove them from the mass spectrometer 100 and clean them. Therefore, the user cannot handle the quadrupole rods 26 in the same way as the ion guides 23, 25, and must request a field engineer to clean the quadrupole rods 26.

[0039] Thus, if the sensitivity of the mass spectrometer 100 is reduced due to contamination of the quadrupole rods 26, the user cannot restore the performance of the mass spectrometer 100 on their own. If the above-described maintenance work is performed despite the high level of contamination of the quadrupole rods 26, the sensitivity of the mass spectrometer 100 may be temporarily restored. However, the sensitivity will soon be reduced again, preventing the user from performing mass analysis. This can lead to problems such as prolonged downtime of the mass spectrometer 100.

[0040] Therefore, the user must determine whether cleaning the ion guides 23 and 25 will restore the performance of the mass spectrometer 100, or whether cleaning of the quadrupole rods 26 is necessary. However, there has not been a method to assist in making such a determination.

[0041] This disclosure proposes a method for estimating parts that may require cleaning by focusing on a phenomenon that occurs during maintenance work performed by a user when the sensitivity of the mass spectrometer 100 has decreased. The key points of this method are as follows.

[0042] It goes without saying that the degree of degradation in sensitivity of the mass spectrometer 100 depends on the degree of contamination of the ion guides 23, 25 and the degree of contamination of the quadrupole rods 26. According to tests conducted by the inventors, a clear difference was observed in the maintenance work time required to temporarily restore sensitivity between (a) a case where the degree of contamination of the quadrupole rods 26 is low (where the ion guides 23, 25 are contaminated, but not the quadrupole rods 26) and (b) a case where the degree of contamination of the quadrupole rods 26 is high.

[0043] That is, in the case of (a) above, the sensitivity of the mass spectrometer 100 temporarily recovered to the sensitivity before the sensitivity decrease within a few seconds after ions of the opposite polarity to the charged-up polarity were started to be passed through the mass spectrometer 100. In contrast, in the case of (b) above, it took several minutes or more after ions of the opposite polarity to the charged-up polarity were started to be passed through the mass spectrometer 100 for the sensitivity of the mass spectrometer 100 to temporarily recover to a level considered necessary for mass analysis.

[0044] The cause of this phenomenon is thought to be the difference in ion transmittance between the ion guides 23, 25 and the quadrupole rods 26. The quadrupole rods 26 operate as a so-called mass filter, transmitting only limited types of ions. Therefore, even if a large number of ions are passed through in order to cancel charged ions, the amount of ions that reach contaminated areas of the quadrupole rods 26 is limited. In contrast, the ion guides 23, 25 do not operate as mass filters, and therefore have high ion transmittance. Therefore, when a large number of ions are passed through in order to cancel charged ions, the ions can be effectively directed to contaminated areas of the ion guides 23, 25.

[0045] Hereinafter, it will be explained with reference to FIGS. 2 to 4 that the speed at which the sensitivity of mass spectrometer 100 temporarily recovers varies depending on the location of contamination.

[0046] [Example of Transition of Ion Intensity] Fig. 2 is a diagram showing an example of transition of ion intensity in a normal case (when there is no contamination). Fig. 3 is a diagram showing an example of transition of ion intensity when the ion guides 23 and 25 are contaminated. Fig. 4 is a diagram showing an example of transition of ion intensity when the quadrupole rod 26 is contaminated.

[0047] Here, we show an example of the transition of ion intensity in positive mode when mass analysis is continued in positive mode and then the polarity mode is switched to negative mode, positive mode, negative mode, and positive mode over a period of several minutes to several tens of minutes.

[0048] If the ion guides 23, 25 and quadrupole rods 26 are not contaminated, the ion intensity remains high (e.g., 100% in FIG. 2) even when the polarity mode is switched between positive and negative modes, as shown in FIG. 2.

[0049] When the ion guides 23 and 25 are contaminated (when the contaminated part is the ion guides 23 and 25 and not the quadrupole rods 26), the ion intensity recovers rapidly after the polarity mode is switched from positive to negative, as shown in Figure 3. However, at switching point A, after the polarity mode is switched from negative to positive, the ion intensity gradually decreases. Thereafter, the ion intensity recovers within a few seconds after the polarity mode is switched from positive to negative.

[0050] When the quadrupole rods 26 are contaminated (when the contaminated location is the quadrupole rods 26 and not the ion guides 23 and 25), the ion intensity gradually recovers after the polarity mode is switched from positive to negative mode, as shown in Figure 4. The recovery rate at this time is much slower than when the ion guides 23 and 25 are contaminated. When the polarity mode is switched from negative to positive mode at switching time A, the ion intensity gradually decreases. Then, when the polarity mode is switched from positive to negative mode at switching time B, the ion intensity gradually recovers.

[0051] Thus, the speed at which the sensitivity of the mass spectrometer 100 temporarily recovers varies depending on the location of contamination. Therefore, this disclosure focuses on the difference in the time required for sensitivity recovery (temporary recovery) and proposes a method that can determine whether the performance of the mass spectrometer 100 can be restored by cleaning the ion guides 23 and 25, or whether cleaning of the quadrupole rods 26 is required. The mass spectrometer 100 according to this embodiment realizes such a method by executing a determination process. The determination process will be described in detail below.

[0052] Note that the determination result as to whether the degree of contamination of the quadrupole rods 26 is low will naturally vary depending on the setting of the threshold value for determining the degree of contamination. Here, if the state in which the sensitivity of the mass spectrometer 100 is restored to a level that is practically usable by simply cleaning the ion guides 23, 25 without cleaning the quadrupole rods 26 continues for a period of time that is considered necessary for mass analysis, it is determined that cleaning of the quadrupole rods 26 is not necessary. Therefore, the threshold value for determining the degree of contamination is set appropriately in accordance with such a determination criterion.

[0053] [Flow of Determination Process] Fig. 5 is a timing chart and a flowchart showing the determination process for determining which parts require cleaning. The timing chart shown in Fig. 5 shows the flow when the determination process is performed after mass spectrometry is performed in positive mode (P mode).

[0054] By performing mass analysis in the positive mode, positive ions gradually contaminate the ion guides 23, 25 and the quadrupole rods 26. The degree of contamination of each of the ion guides 23, 25 and the quadrupole rods 26 is thought to differ depending on the accumulation time of the mass analysis.

[0055] As shown in the timing chart of Figure 5, after the mass analysis in the positive mode is completed, the polarity mode is switched from the positive mode to the negative mode (N mode) to determine the cleaning location. This reverses the polarity of the polarity mode. By reversing the polarity, negative ions are guided to the intermediate chambers 201 to 203 and the analysis chamber 204 of the mass spectrometer 100. This gradually neutralizes the large number of positive ions accumulated in the ion guides 23, 25 and the quadrupole rods 26. Note that a liquid sample is continuously supplied to the electrospray ion source 21 from the start to the end of the determination process.

[0056] As a result, the contamination states of the ion guides 23, 25 and the quadrupole rods 26 are "initialized" to a predetermined state. Therefore, the negative mode period T0 is an initialization period for initializing the states of the ion guides 23, 25 and the quadrupole rods 26. If the period T0 is too short, the initialization will be insufficient. For this reason, it is desirable to set the period T0 with a margin of error relative to the period required for initialization. Hereinafter, the portion of the housing 2 in which the ion guides 23, 25 and the quadrupole rods 26 are arranged will be abbreviated as "inside the device," and the initialization of the states of the ion guides 23, 25 and the quadrupole rods 26 will sometimes be abbreviated as "initialization inside the device."

[0057] After the inside of the device is initialized, the polarity mode is switched from negative mode to positive mode, thereby reversing the polarity of the polarity mode. By reversing the polarity, positive ions are guided into the intermediate chambers 201-203 and the analysis chamber 204 of the mass spectrometer 100. The positive mode period T1 is the first period in which a virtual mass analysis is performed after the inside of the device is initialized to reproduce the contamination state. Therefore, by setting the period T1 to an appropriate length, the contamination state inside the device can be reproduced more accurately.

[0058] Ion intensity is measured at the beginning and end of period T1. That is, after the initialization period, ion intensity A is measured in positive mode when the first period begins, and ion intensity B is measured in positive mode at the end of the first period. In Figure 5, the ratio of ion intensity B to ion intensity A indicates the rate of sensitivity reduction due to the hypothetical mass spectrometry.

[0059] After the period T1, the polarity mode is switched from the positive mode to the negative mode. This reverses the polarity of the polarity mode. The reversal of the polarity begins to neutralize the inside of the device. The negative mode period T2 is a second period for determining whether the sensitivity of the mass spectrometer 100 can be restored to a level suitable for practical use by simply cleaning the ion guides 23 and 25 when the inside of the device is contaminated. In other words, the period T2 is shorter than the time required for the performance of the quadrupole rods 26 to temporarily recover, but is sufficient for the performance of the ion guides 23 and 25 to temporarily recover. Appropriate values ​​for both the periods T1 and T2 can be determined by repeating experiments.

[0060] As described above, there is a clear difference in the maintenance work time required to temporarily restore sensitivity between (a) a case where the quadrupole rods 26 are lightly contaminated and (b) a case where the quadrupole rods 26 are highly contaminated. In the above case (a), the sensitivity of the mass spectrometer 100 is restored to a level considered necessary for mass analysis within a few seconds after ions of opposite polarity to the charged-up polarity are introduced into the mass spectrometer 100.

[0061] Based on this fact, the period T2 is set to about several seconds. Therefore, after the period T2 of about several seconds, the polarity mode is switched from the negative mode to the positive mode. This reverses the polarity of the polarity mode. By reversing the polarity, positive ions are guided into the intermediate chambers 201-203 and the analysis chamber 204 of the mass spectrometer 100. Immediately after the polarity mode is switched from the negative mode to the positive mode, the ion intensity C is measured in the positive mode.

[0062] The above processing described based on the timing charts yields ion intensities A to C. Ion intensity A is an example of a first ion intensity, ion intensity B is an example of a second ion intensity, and ion intensity C is an example of a third ion intensity. Based on these ion intensities, the control device 3 of the mass spectrometer 100 determines the areas requiring cleaning according to the steps within the boxes shown in FIG. 5 .

[0063] That is, the control device 3 determines that cleaning is necessary when "ionic strength B≦(threshold Th1×ionic strength A)" is true (steps S15 and S21), and determines that cleaning is not necessary when "ionic strength B≦(threshold Th1×ionic strength A)" is not true (steps S15 and S16). Note that the threshold Th1 is a value that exceeds 0 and is less than 1. For example, the threshold Th1 may be 0.5.

[0064] In this determination, the ratio of "ion intensity B" to "ion intensity A immediately after initialization inside the device" is essentially determined, and the degree of contamination progressing through virtual mass analysis is evaluated.

[0065] If "ionic strength C ≥ (threshold Th2 × ionic strength A)" is true, the control device 3 determines that only the ion guides 23 and 25 need to be cleaned (steps S17 and S18). If "ionic strength C ≥ (threshold Th2 × ionic strength A)" is not true, the control device 3 determines that the ion guides 23 and 25 and the quadrupole rods 26 need to be cleaned (steps S17 and S19). Note that threshold Th2 is a value that exceeds 0 and is less than 1. Furthermore, threshold Th2 is a value that is greater than threshold Th1. For example, threshold Th2 may be 0.8. Threshold Th2 may also be a value that exceeds 0.8 and is approximately close to 1.

[0066] This determination essentially determines the ratio of "ion intensity C" to "ion intensity A immediately after initialization inside the device," thereby evaluating whether the sensitivity of the mass spectrometer 100 can be restored (temporarily restored) after a few seconds of maintenance work (neutralization by polarity mode reversal) from a state in which contamination has progressed.

[0067] Here, the case where the determination process is performed after mass analysis is performed in positive mode is illustrated. However, if the determination process is performed after mass analysis is continued in negative mode, the positive and negative modes in the timing chart shown in FIG. 5 are reversed.

[0068] Here, an example has been described in which an initialization period is set to initialize the states of the ion guides 23, 25 and the quadrupole rods 26. However, measurement of the ion intensity A may be started in the polarity mode used in mass spectrometry without setting an initialization period. That is, the initialization period T0 shown in FIG. 5 is not essential in this embodiment. However, if more precise measurement is desired, it is preferable to set the initialization period T0.

[0069] [Flowchart of Determination Process] Next, the determination process described with reference to Fig. 5 will be described using a series of flowcharts and example screens. Fig. 6 and Fig. 7 are flowcharts for explaining the determination process for determining parts that require cleaning. Fig. 8 is a diagram showing an example screen showing the test results of the determination process.

[0070] First, the control device 3 determines that the mass analysis has been completed (step S1), and then determines whether the mass analysis was performed in the positive mode (step S2).

[0071] If the mass spectrometry mode is the positive mode, the control device 3 sets the positive mode as the first polarity mode and the negative mode as the second polarity mode (step S3).If the mass spectrometry mode is the negative mode, the control device 3 sets the negative mode as the first polarity mode and the positive mode as the second polarity mode (step S4).

[0072] Next, the control device 3 controls the polarity mode to the second polarity mode (step S5). In other words, the control device 3 executes control corresponding to the initialization period T0 shown in Fig. 5. Note that the liquid sample is continuously supplied to the electrospray ion source 21 from the start to the end of the determination process.

[0073] Next, the control device 3 determines whether the period T0 shown in FIG. 5 has elapsed (step S6). The control device 3 waits until the period T0 has elapsed. The period T0 is an example of an initialization period. After the period T0 has elapsed, the control device 3 switches the polarity mode from the second polarity mode to the first polarity mode (step S7). Next, the control device 3 measures the ion intensity A immediately after switching to the first polarity mode (step S8). More specifically, the control device 3 measures the ion intensity A in the first polarity mode by obtaining a detection value from the detector 28.

[0074] Step S8 is an example of "processing for measuring the first ion intensity of the sample component in the first polarity mode."

[0075] Steps S5 to S7 are an example of "processing for returning the polarity mode to the first polarity mode after an initialization period has elapsed since switching the polarity mode from the first polarity mode to the second polarity mode when the first polarity mode was used in mass spectrometry." The control device 3 measures the first ion intensity when the polarity mode is returned to the first polarity mode after an initialization period has elapsed since switching the polarity mode from the first polarity mode to the second polarity mode. In other words, "processing for measuring the first ion intensity of the sample component in the first polarity mode" includes "processing for measuring the first ion intensity when the polarity mode is returned to the first polarity mode after an initialization period has elapsed since switching the polarity mode from the first polarity mode to the second polarity mode."

[0076] As already explained, the measurement of the ion intensity A may be started in the polarity mode used in the mass analysis without setting the initialization period. In this case, the flow of the flowchart is changed after step S3 or step S4 so that the ion intensity A is measured in the polarity mode used in the mass analysis.

[0077] After step S8, the control device 3 determines whether the period T1 (first period) shown in FIG. 5 has elapsed (step S9). The control device 3 waits until the period T1 has elapsed. After the period T1 has elapsed, the control device 3 measures the ion intensity B in the first polarity mode immediately before switching the polarity mode (step S10). More specifically, the control device 3 measures the ion intensity B by obtaining a detection value from the detector 28.

[0078] Steps S9 and S10 are an example of a process for measuring the second ion intensity of a sample component in the first polarity mode after the polarity mode is returned to the first polarity mode and a first period in the first polarity mode has elapsed.

[0079] Step S10 is an example of "a process of measuring a second ion intensity of a sample component in a first polarity mode when a first period has elapsed after measuring a first ion intensity."

[0080] Next, the control device 3 switches the polarity mode from the first polarity mode to the second polarity mode (step S11). Step S11 is an example of "processing of switching the polarity mode from the first polarity mode to the second polarity mode after measuring the second ion intensity."

[0081] Next, the control device 3 determines whether the period T2 (second period) shown in FIG. 5 has elapsed (step S12). The control device 3 waits until the period T2 has elapsed. After the period T2 has elapsed, the control device 3 switches the polarity mode from the second polarity mode to the first polarity mode (step S13). Next, the control device 3 measures the ion intensity C in the first polarity mode (step S14). More specifically, the control device 3 measures the ion intensity C by obtaining a detection value from the detector 28.

[0082] Steps S12 to S14 are an example of a process of "returning the polarity mode to the first polarity mode when a second period shorter than the first period has elapsed, and measuring the third ion intensity of the sample component in the first polarity mode."

[0083] Next, the control device 3 determines whether or not "ionic strength B≦(threshold Th1×ionic strength A)" is true (step S15). If "ionic strength B≦(threshold Th1×ionic strength A)" is not true, the control device 3 determines that cleaning of the components (ion guides 23, 25 and quadrupole rods 26) is unnecessary (step S16). Here, the "contamination standard for determining that cleaning is necessary" is an example of a "contamination standard." In this embodiment, the necessity of cleaning is determined based on the contamination standard. However, a standard that is less strict than the standard based on the necessity of cleaning may be set as the "contamination standard."

[0084] If "ionic strength B≦(threshold Th1×ionic strength A)" is true, the control device 3 determines whether "ionic strength C≧(threshold Th2×ionic strength A)" is true (step S17). If "ionic strength C≧(threshold Th2×ionic strength A)" is true, the control device 3 determines that only the ion guides 23 and 25 need to be cleaned (step S18). If "ionic strength C≧(threshold Th2×ionic strength A)" is not true, the control device 3 determines that the ion guides 23 and 25 and the quadrupole rods 26 need to be cleaned (step S19).

[0085] After the processing of step S16, step S18, or step S19, the control device 3 displays the determination result on the display device 34 (step S20). More specifically, the control device 3 outputs a display signal for displaying the determination result to the display device 34. This display signal includes a signal for prompting the user to clean the ion guides 23, 25, or to clean the ion guides 23, 25 and the quadrupole rods 26.

[0086] Steps S15, S17, S18, and S20 are an example of "a process of determining that the degree of contamination of the ion guide, of the ion guide and the mass separator, meets the contamination standard when the second ion intensity is smaller than the intensity corresponding to the first reference ratio of the first ion intensity and the third ion intensity is greater than the intensity corresponding to the second reference ratio of the first ion intensity, and outputting a display signal to display the determination result to a user."

[0087] Steps S15, S17, S19, and S20 are an example of a process for determining that the degree of contamination of the mass separator and ion guide satisfies the contamination standard and outputting an indication signal if the second ion intensity is smaller than the intensity corresponding to the first reference ratio of the first ion intensity and the third ion intensity is smaller than the intensity corresponding to the second reference ratio of the first ion intensity.

[0088] After step S20, the control device 3 ends the process based on this flowchart. Note that the control device 3 may accept an operation by the user to set at least one of the periods T0, T1, and T2.

[0089] As described above, the control device 3 performs a determination process to determine the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity.

[0090] [Screen Example] Fig. 8 shows an example of a determination result displayed on the display device 34. A screen 340 shown in Fig. 8 is an example of a screen displayed when the control device 3 determines that only the ion guides 23 and 25 need to be cleaned. The screen 340 shows that the ion guides 23 and 25 need to be cleaned, but that the quadrupole rods 26 do not need to be cleaned.

[0091] Furthermore, the screen 340 displays detailed data of the test by the determination process, such as the type of first polarity mode and ionic intensities A, B, and C (see FIG. 2 ). The screen 340 also displays, as detailed data, a recovery rate based on ionic intensity B when ionic intensity A is used as a reference, and a recovery rate based on ionic intensity C when ionic intensity A is used as a reference.

[0092] As described above, this embodiment can provide the user with information necessary to determine the degree of contamination of the ion guides 23, 25 and the quadrupole rods 26. A feature of the procedure according to this embodiment is that it estimates the location of contamination by focusing on the time for which ions are transmitted with a second polarity opposite to the first polarity in which a decrease in intensity is observed, and the rate of improvement in intensity when the polarity is returned to the original first polarity. This embodiment can determine whether cleaning of the inside of the device is necessary and which locations should be cleaned. Therefore, this embodiment enables appropriate maintenance of the mass spectrometer. This reduces the risk of a recurrence of a decrease in intensity during mass analysis. As a result, the downtime of the mass spectrometer can be reduced.

[0093] 9 shows a modified example of the determination process for determining which parts require cleaning. Up to now, an example has been described in which ion strength A and ion strength C are used to determine whether cleaning of the ion guides 23 and 25 can restore the performance of the mass spectrometer 100 or whether cleaning of the quadrupole rods 26 is required.

[0094] 9, such a distinction may be made using ionic strength B and ionic strength C. More specifically, the controller 3 determines whether or not "ionic strength C>ionic strength B" is satisfied (step S170). If the determination in step S170 is YES, the controller 3 determines that only the ion guides 23 and 25 need to be cleaned (step S18). If the determination in step S170 is NO, the controller 3 determines that the ion guides 23 and 25 and the quadrupole rods 26 need to be cleaned (step S19).

[0095] That is, the control device 3 evaluates whether the sensitivity of the mass spectrometer 100 can be restored (ion intensity C>ion intensity B) after a few seconds of maintenance work (processing during period T2) from a state in which contamination has progressed (ion intensity B). In a modified example, the processes of steps S15, S16, and S20 shown in FIG. 7 may be performed together.

[0096] [Aspects] It will be understood by those skilled in the art that the above-described embodiments and their modifications are specific examples of the following aspects.

[0097] (Item 1) A mass spectrometer according to one aspect is a mass spectrometer equipped with a mass separator, the mass spectrometer comprising an ionization chamber for ionizing sample components, an ion guide for guiding ions generated in the ionization chamber to the mass separator, a detector for detecting ions separated by the mass separator, and a control device for measuring ion intensities of the sample components based on detection values ​​from the detector, wherein the control device is configured to execute a determination process for determining a contamination state of the mass spectrometer by switching polarity modes between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, the determination process including a process for measuring a first ion intensity of the sample components in the first polarity mode, and a process for measuring a second ion intensity in the first polarity mode after measuring the first ion intensity. the measurement of a second ion intensity of the sample component in a first polarity mode after a first period in the measurement mode has elapsed; the measurement of a second ion intensity by switching the polarity mode from the first polarity mode to the second polarity mode after the second period, which is shorter than the first period, has elapsed; the measurement of a third ion intensity of the sample component in the first polarity mode after switching the polarity mode from the first polarity mode to the second polarity mode; and the measurement of a third ion intensity of the sample component in the first polarity mode when the second ion intensity is smaller than the intensity corresponding to a first reference ratio of the first ion intensity and the third ion intensity is larger than the intensity corresponding to a second reference ratio of the first ion intensity, determining that the degree of contamination of the ion guide, of the ion guide and the mass separator, satisfies the contamination standard, and outputting a display signal to display the determination result to a user.

[0098] According to the mass spectrometer described in paragraph 1, it is possible to provide the user with information necessary to determine the degree of contamination of the ion guide and mass separator.

[0099] (Clause 2) The mass spectrometer described in paragraph 2 is the mass spectrometer described in paragraph 1, wherein the determination process further includes a process of determining that the degree of contamination of the mass separator and ion guide meets the contamination standard when the second ion intensity is smaller than the intensity corresponding to a first reference ratio of the first ion intensity and the third ion intensity is smaller than the intensity corresponding to a second reference ratio of the first ion intensity, and outputting an indication signal.

[0100] According to the mass spectrometer described in paragraph 2, it is possible to provide the user with the information necessary to determine the degree of contamination of the ion guide and mass separator.

[0101] (Item 3) The mass spectrometer according to item 3 is the mass spectrometer according to item 1 or 2, wherein the display signal includes a signal for prompting the user to clean the ion guide.

[0102] According to the mass spectrometer described in paragraph 3, the user can know that the ion guide needs to be cleaned.

[0103] (4) The mass spectrometer described in paragraph 4 is the mass spectrometer described in any one of paragraphs 1 to 3, wherein the process of measuring the first ion intensity of the sample component in the first polarity mode includes a process of measuring the first ion intensity when the polarity mode is switched back to the first polarity mode after an initialization period has elapsed since the polarity mode was switched from the first polarity mode to the second polarity mode.

[0104] According to the mass spectrometer described in paragraph 4, by setting the initialization period, it is possible to execute the determination process in a state where the contamination state inside the device is more accurately reproduced.

[0105] (Item 5) The mass spectrometer according to item 5 is the mass spectrometer according to any one of items 1 to 4, wherein the mass separator is composed of a plurality of rod electrodes.

[0106] According to the mass spectrometer described in item 5, it is possible to provide the user with information necessary to determine the degree of contamination of the mass separator formed by a plurality of rod electrodes.

[0107] (Item 6) The mass spectrometer described in item 6 is the mass spectrometer described in any one of items 1 to 5, wherein the ion guide is composed of a plurality of electrodes, and the plurality of electrodes form an ion passage space through which ions travel.

[0108] According to the mass spectrometer described in paragraph 6, it is possible to provide a user with information necessary to determine the degree of contamination of an ion guide that is composed of a plurality of electrodes arranged to surround the ion optical axis.

[0109] (Clause 7) A method according to another aspect is a method for controlling a mass spectrometer having a mass separator, the method being realized by a processor executing a program stored in a memory. The mass spectrometer comprises an ionization chamber that ionizes sample components, an ion guide that guides ions generated in the ionization chamber to the mass separator, a detector that detects ions separated by the mass separator, and a control device that measures the ion intensity of the sample components based on the detection value of the detector. The control device is configured to execute a determination process for determining the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity. The method includes, as a step related to the determination process, detecting the first ion of the sample components in the first polarity mode. measuring a second ion intensity of the sample component in the first polarity mode when a first period in the first polarity mode has elapsed after measuring the first ion intensity; switching the polarity mode from the first polarity mode to the second polarity mode after measuring the second ion intensity, and returning the polarity mode to the first polarity mode when a second period shorter than the first period has elapsed, and measuring a third ion intensity of the sample component in the first polarity mode; and determining that the degree of contamination of the ion guide, of the ion guide and the mass separator, meets the contamination standard when the second ion intensity is smaller than the intensity corresponding to a first reference proportion of the first ion intensity and the third ion intensity is greater than the intensity corresponding to a second reference proportion of the first ion intensity, and outputting a display signal to display the determination result to a user.

[0110] The method described in Section 7 can provide a user with the information necessary to determine the degree of contamination of the ion guide and mass separator.

[0111] (Item 8) A mass spectrometer according to another aspect is a mass spectrometer equipped with a mass separator, the mass spectrometer comprising an ionization chamber for ionizing sample components, an ion guide for guiding ions generated in the ionization chamber to the mass separator, a detector for detecting ions separated by the mass separator, and a control device for measuring ion intensities of the sample components based on values ​​detected by the detector, wherein the control device is configured to execute a determination process for determining a contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, and the determination process is performed from an initial polarity mode after switching the polarity mode from the first polarity mode to the second polarity mode. the measurement of a second ion intensity of the sample component in the first polarity mode after a first period has elapsed after the polarity mode has been returned to the first polarity mode; the measurement of a second ion intensity of the sample component in the first polarity mode after the second period has elapsed after the polarity mode has been returned to the first polarity mode; the measurement of a third ion intensity of the sample component in the first polarity mode after the measurement of the second ion intensity by switching the polarity mode from the first polarity mode to the second polarity mode, and after a second period shorter than the first period has elapsed, by switching the polarity mode back to the first polarity mode; and the measurement of a third ion intensity of the sample component in the first polarity mode if the third ion intensity is greater than the second ion intensity by determining that the degree of contamination of the ion guide satisfies the contamination criterion and outputting a display signal to display the determination result to a user.

[0112] According to the mass spectrometer described in paragraph 8, it is possible to provide the user with the information necessary to determine the degree of contamination of the ion guide and mass separator.

[0113] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims.

[0114] 2 Housing, 3 Control device, 4 Power supply circuit, 5 Rotary pump, 6 Turbomolecular pump, 21 Electrospray ion source, 22 Desolvation tube, 23, 25 Ion guide, 24 Skimmer, 26 Quadrupole rod, 27 Reaction chamber, 28 Detector, 31 Processor, 32 Memory, 33 Input / output interface, 34 Display device, 35 Input device, 100 Mass analyzer, 200 Ionization chamber, 201 to 203 Intermediate chamber, 204 Analysis chamber, 340 Screen, C1 Ion optical axis.

Claims

1. A mass spectrometer comprising a mass separator, an ionization chamber for ionizing sample components, an ion guide for guiding the ions generated in the ionization chamber to the mass separator, a detector for detecting the ions separated by the mass separator, and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, wherein the control device is configured to execute a determination process for determining the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, and the determination process includes: in the first polarity mode, a process of measuring a first ion intensity of the sample components; after measuring the first ion intensity, when a first period in the first polarity mode has elapsed, a process of measuring a second ion intensity of the sample components in the first polarity mode; after measuring the second ion intensity, switching the polarity mode from the first polarity mode to the second polarity mode, and when a second period shorter than the first period has elapsed, returning the polarity mode to the first polarity mode, and a process of measuring a third ion intensity of the sample components in the first polarity mode; when the second ion intensity is smaller than the intensity corresponding to a first reference ratio of the first ion intensity and the third ion intensity is larger than the intensity corresponding to a second reference ratio of the first ion intensity, determining that the degree of contamination of the ion guide among the ion guide and the mass separator satisfies a contamination standard, and outputting a display signal for displaying the determination result to the user. A mass spectrometer.

2. The mass spectrometer according to claim 1, wherein the determination process further includes, when the second ion intensity is smaller than the intensity corresponding to a first reference ratio of the first ion intensity and the third ion intensity is smaller than the intensity corresponding to the second reference ratio of the first ion intensity, determining that the degree of contamination of the mass separator and the ion guide satisfies the contamination standard, and outputting the display signal.

3. The mass spectrometer according to claim 1 or 2, wherein the display signal includes a signal for prompting the user to clean the ion guide.

4. In the first polarity mode, the process of measuring the first ion intensity of the sample component includes the process of measuring the first ion intensity when, after switching the polarity mode from the first polarity mode to the second polarity mode and after the elapse of the initialization period, the polarity mode is returned to the first polarity mode. The mass spectrometer according to claim 1 or claim 2.

5. The mass separator is composed of a plurality of rod electrodes. The mass spectrometer according to claim 1 or claim 2.

6. The ion guide is composed of a plurality of electrodes, and the plurality of electrodes form an ion passage space through which ions travel. The mass spectrometer according to claim 1 or claim 2.

7. A method for controlling a mass spectrometer equipped with a mass separator, the method being realized by a program stored in a memory being executed by a processor, the mass spectrometer comprising: an ionization chamber for ionizing sample components; an ion guide for guiding ions generated in the ionization chamber to the mass separator; a detector for detecting ions separated by the mass separator; and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, the control device being configured to execute a determination process for determining the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, the method comprising, as steps related to the determination process: measuring a first ion intensity of the sample components in the first polarity mode; after measuring the first ion intensity, when a first period in the first polarity mode has elapsed, measuring a second ion intensity of the sample components in the first polarity mode; after measuring the second ion intensity, switching the polarity mode from the first polarity mode to the second polarity mode, and when a second period shorter than the first period has elapsed, returning the polarity mode to the first polarity mode and measuring a third ion intensity of the sample components in the first polarity mode; when the second ion intensity is smaller than the intensity corresponding to a first reference ratio of the first ion intensity and the third ion intensity is larger than the intensity corresponding to a second reference ratio of the first ion intensity, determining that the degree of contamination of the ion guide among the ion guide and the mass separator satisfies a contamination criterion, and outputting a display signal for displaying the determination result to the user.

8. A mass spectrometer comprising a mass separator, an ionization chamber for ionizing sample components, an ion guide for guiding the ions generated in the ionization chamber to the mass separator, a detector for detecting the ions separated by the mass separator, and a control device for measuring the ion intensity of the sample components based on the detection value of the detector, wherein the control device is configured to execute a determination process for determining the contamination status of the mass spectrometer by switching the polarity mode between a first polarity mode for separating ions of a first polarity and a second polarity mode for separating ions of a second polarity, and the determination process includes: after switching the polarity mode from the first polarity mode to the second polarity mode and after the elapse of an initialization period, returning the polarity mode to the first polarity mode; when the first period in the first polarity mode has elapsed after the polarity mode has been returned to the first polarity mode, measuring the second ion intensity of the sample components in the first polarity mode; after measuring the second ion intensity, switching the polarity mode from the first polarity mode to the second polarity mode, and when a second period shorter than the first period has elapsed, returning the polarity mode to the first polarity mode and measuring the third ion intensity of the sample components in the first polarity mode; and when the third ion intensity is greater than the second ion intensity, determining that the degree of contamination of the ion guide satisfies a contamination criterion and outputting a display signal for displaying the determination result to the user.

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