WO2023042369A1 - Mass spectroscopy device, ionization device, and ionization method - Google Patents

Abstract

Provided is a mass spectroscopy device 1 comprising: a probe 111 which sprays a liquid sample; an electrical discharge electrode 112 which is disposed at a position where the liquid sample is sprayed from the probe 111; an electrical discharge electrode attachment part 115 to which is provided a conductive part 116 that is conductive with the electrical discharge electrode, and to which the electrical discharge electrode is detachably attached; a voltage application unit 2, 43 which applies, to the conductive part 116, a voltage for causing the electrical discharge electrode 112 to generate a corona discharge; a current measurement unit 2, 44 which measures a current value flowing through the conductive part while the voltage is being applied; a determination unit 45 which determines that the electrical discharge electrode 112 is attached if the current value exceeds a predetermined threshold; and an output unit 46 which outputs a result of the determination by the determination unit 45.

Description

Mass spectrometer, ionization device, and ionization method

The present invention relates to a technique for ionizing a liquid sample in an ion analyzer such as a mass spectrometer.

Equipped with a liquid chromatograph (LC) that separates sample components and a mass spectrometer (MS) that ionizes and mass analyzes the separated components in order to qualitatively and quantify the components contained in liquid samples. A liquid chromatograph-mass spectrometer (LC-MS) is used. As an ion source for the mass spectrometer, for example, an electrospray ionization (ESI) device or an atmospheric pressure chemical ionization (APCI) device is used. An ESI instrument is used when the analyte is a highly polar compound, and an APCI instrument is used when it is a less polar compound. Further, when a sample contains both high-polarity components and low-polarity components, a dual ionization device having both the functions of an ESI device and an APCI device is used (for example, Patent Document 1).

When performing atmospheric pressure chemical ionization with an APCI device or a dual ionization device, a liquid sample in which sample components are dissolved in an ionizable solvent is sprayed from the tip of the probe into the ionization chamber, and the liquid sample is sprayed from the probe. A voltage of a predetermined magnitude (APCI voltage) is applied to a discharge electrode placed at a position to generate a corona discharge. The solvent in the liquid sample sprayed into the ionization chamber is ionized by the corona discharge, and then the sample components are ionized by exchange of H+ (protons) between solvent ions and sample components. In many cases, a needle-like needle electrode (corona needle) is used as the discharge electrode, and corona discharge is generated between the corona needle and a sampling cone provided on the partition wall between the ionization chamber and the analysis chamber.

WO2015/118681

　In the APCI device and the dual ionization device, the solvent and sample components sprayed from the probe are sprayed onto the discharge electrode, and the solvent and sample components adhere to the electrode surface. When these substances adhere to the surface of the discharge electrode, the state of corona discharge becomes unstable, resulting in variations in ionization efficiency. Therefore, it is necessary to periodically remove the discharge electrode from the ionization device and clean it. In addition, as an official method for testing pesticides contained in food, it is specified that sample components should be ionized by the ESI method. Sometimes it is necessary.

　After removing the discharge electrode from the ionization device, it is necessary to attach the discharge electrode to the ionization device when ionizing the sample components again by the APCI method. At this time, if the user does not notice that the discharge electrode has been removed from the ionization device and continues the measurement in that state, corona discharge will not occur and the sample components will not be ionized, resulting in And there was a problem of losing time.

The problem to be solved by the present invention is to provide a technology that allows the user to easily check the attachment/detachment state of the discharge electrode in an ionization device that ionizes sample components by atmospheric pressure chemical ionization.

An ionization device and a mass spectrometer according to the present invention, which have been made to solve the above problems,
a probe for spraying a liquid sample;
a discharge electrode arranged at a position where the liquid sample is sprayed from the probe;
a discharge electrode mounting portion provided with a current-carrying portion for the discharge electrode and to which the discharge electrode is detachably mounted;
a voltage applying unit that applies a voltage to the current-carrying unit to cause corona discharge in the discharge electrode;
a current measuring unit that measures a current value flowing through the current-carrying unit while the voltage is being applied;
a determination unit that determines that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and an output unit that outputs a result of determination by the determination unit.

Another aspect of the present invention, which has been made to solve the above problems, is an ionization method of ionizing a liquid sample by generating corona discharge in a discharge electrode provided at a position where the liquid sample is sprayed from a probe. in
a step of applying a voltage to the discharge electrode to generate a corona discharge and measuring a current value flowing through a current-carrying portion to the discharge electrode;
determining that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and outputting the result of the determination.

In the present invention, a current value that is lower than the current value that flows through the discharge electrode when corona discharge is generated in the discharge electrode and that cannot be reached when corona discharge is not generated is preset as the threshold value. In the present invention, the current value flowing through the current-carrying portion to the discharge electrode is measured when a predetermined voltage for generating corona discharge is applied. At this time, if the discharge electrode is attached, a current exceeding the threshold value flows through the current-carrying portion, and if the discharge electrode is not attached, no current flows through the current-carrying portion. In the present invention, the attachment/detachment state of the discharge electrode is determined based on the result of comparing the current value measured at this time with the threshold value, and the result is output. Therefore, the user can easily check the attachment/detachment state of the discharge electrode. can do.

1 schematically shows the appearance of a housing of an embodiment of a mass spectrometer according to the present invention, including an ionization apparatus according to an embodiment of the present invention; FIG. 2 is a configuration diagram of the essential parts of the mass spectrometry system of the present embodiment. 4 is a flowchart of an ionization method according to an embodiment of the present invention, which is performed by the mass spectrometry system of the present embodiment; 4 is a flow chart of another embodiment of the ionization method according to the present invention, which is performed by the mass spectrometry system of this embodiment. 4 is a flow chart of still another embodiment of the ionization method according to the present invention, which is performed by the mass spectrometry system of this embodiment.

An embodiment of an ionization apparatus, a mass spectrometer, and an ionization method according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing the appearance of the housing of a mass spectrometer 1 including the ionization device of this embodiment (components inside the housing are not shown). FIG. 2 is a configuration diagram of essential parts of a mass spectrometry system 100 having a mass spectrometer 1, a power supply unit 2 for supplying electric power to each part of the mass spectrometer 1, and a control/processing unit 4 for controlling these operations. .

The housing of the mass spectrometer 1 includes a first housing 31 constituting the ionization chamber 11, a first intermediate vacuum chamber 12, a second intermediate vacuum chamber 13, and a second housing constituting a vacuum chamber housing the analysis chamber 14. It is composed of a body 32 and a third housing 33 mainly including the power supply unit 2 and the like. The first housing 31 is provided with an opening for attaching and detaching the corona needle 112 disposed in the ionization chamber 11 and a front door 311 for opening and closing the opening at a position facing the ionization chamber 11 on the front surface. It is The open/close state of the front door 311 is detected by a sensor (not shown), and the detection result of the sensor is sent to the control/processing section 4 . A Hall sensor or a microswitch, for example, can be used as the sensor.

The mass spectrometer 1 includes an ionization chamber 11 , a first intermediate vacuum chamber 12 , a second intermediate vacuum chamber 13 and an analysis chamber 14 . The ionization chamber 11 is at approximately atmospheric pressure. As described above, the first intermediate vacuum chamber 12, the second intermediate vacuum chamber 13, and the analysis chamber 14 are provided in the second housing 32, and a multi-stage differential evacuation system in which the degree of vacuum increases stepwise in this order. It has a configuration of

The ionization device of the mass spectrometer of this embodiment includes a probe (ESI probe) 111 for electrospray ionization (ESI) of a liquid sample and an ionization chamber 11 for atmospheric pressure chemical ionization (APCI) of the liquid sample. It is a dual ionizer with a corona needle 112 . The ESI probe 111 is detachably attached to the top of the first housing 31 . The corona needle 112 is detachably attached to a needle attachment portion 115 provided on the side surface of the first housing 31 . In addition, the needle mounting portion 115 is provided with a current-carrying portion 116 for the corona needle 112 .

The ions generated in the ionization chamber 11 are drawn into the first intermediate vacuum chamber 12 through the desolvation pipe 113 due to the pressure difference in the first intermediate vacuum chamber 12 located in the subsequent stage. The solvent removal pipe 113 is heated by a heating block 114 forming a part of the partition wall, and the solvent removal is further accelerated while passing through the solvent removal pipe 113 . The heating block 114 is heated by energizing a heater (not shown) or the like.

An ion guide 121 composed of a plurality of rod-shaped electrodes is arranged in the first intermediate vacuum chamber 12 . The ions introduced through the desolvation pipe 113 are converged by the ion guide 121 near the ion optical axis (central axis of the flight direction of the ions) C, and enter the second intermediate vacuum chamber 13 through the top opening of the skimmer 122. .

An ion guide 131 that converges ions entering through the skimmer 122 is also arranged in the second intermediate vacuum chamber 13 . The analysis chamber 14 includes a front-stage quadrupole mass filter (Q1) 141, a collision cell 142 in which a multipole ion guide (q2) 143 is installed, a rear-stage quadrupole mass filter (Q3) 144, and an ion detector. 145 is installed.

Based on the control signal from the control/processing unit 4, the power supply unit 2 includes an ESI probe 111, a corona needle 112, an ion guide 121, an ion guide 131, a front-stage quadrupole mass filter 141, a multipole ion guide 143, and a rear-stage quadrupole ion guide 143. A predetermined voltage is applied to each of the heavy pole mass filters 144 and the like. Also, the power supply unit 2 measures the current value flowing through the corona needle 112 .

The control/processing unit 4 includes a storage unit 41 and functional blocks including an attachment/detachment confirmation reception unit 42, a voltage application unit 43, a current measurement unit 44, a determination unit 45, an output unit 46, a measurement condition setting unit 47, and a measurement A control unit 48 is provided. The entity of the control/processing unit 4 is a personal computer, and each functional block described above is realized by executing a mass spectrometry program pre-installed in the computer with a processor. An input unit 5 and a display unit 6 are connected to the control/processing unit 4 .

The characteristic operation of the mass spectrometer 1 of this embodiment will be described below.

When using the mass spectrometer 1 to ionize the liquid sample by the APCI method, the user opens the front door 311 and attaches the corona needle 112 . Alternatively, make sure the corona needle 112 is already installed. After that, when the user closes the front door 311 (step 1), the sensor provided on the front door 311 detects that the front door 311 is closed, and transmits the detection signal to the control/processing section 4. (Step 2).

When the control/processing unit 4 receives the signal that the front door 311 is closed, the voltage applying unit 43 applies the APCI voltage from the power supply unit 2 to the energizing unit 116 of the corona needle 112 (step 3). In parallel with this, the current measuring unit 44 measures the value of the current flowing through the conducting unit 116 (step 4). At this time, if the corona needle 112 is properly attached, the application of the APCI voltage causes corona discharge in the corona needle 112, thereby ionizing the air in the ionization chamber 11 and causing current to flow. On the other hand, if the corona needle 112 is not attached, applying the APCI voltage will (substantially) not flow any current.

Therefore, the APCI voltage is applied in advance with and without the corona needle 112 attached, respectively, and the current flowing through the current-carrying portion 116 is measured. A current value that can be reached at the time of application and that cannot be reached when the corona needle 112 is not attached is set as a threshold value.

The present inventor actually applied the APCI voltage (-5 kV) to the current-carrying portion 116 with and without the corona needle 112 attached, and measured the value of the current flowing through the current-carrying portion 116. , the current value with the corona needle 112 attached was 207.68 μA, and the current value without the corona needle 112 attached was 0.39 μA. Although the above threshold differs depending on the arrangement of the parts constituting the ionization device (especially the arrangement of the corona needle 112) and the magnitude of the APCI voltage, it is typically a value of 10 μA or more and 1 A or less. The APCI voltage applied to the corona needle 112 for confirming attachment/detachment of the corona needle 112 is preferably a negative voltage. Generally, applying a negative voltage to the corona needle 112 causes a larger current to flow than applying a positive voltage. Therefore, since the difference between the current value when the corona needle 112 is attached and the current value when the corona needle 112 is not attached becomes large, the attachment/detachment state of the corona needle 112 can be determined more accurately.

When the current value flowing through the energizing section 116 is obtained, the determining section 45 checks whether the measured current value exceeds a predetermined threshold value. When the current value obtained by the current measuring unit 44 exceeds the threshold (YES in step 5), it is determined that the corona needle 112 is correctly attached (step 6). On the other hand, if the current value is equal to or less than the threshold value (NO in step 5), it is determined that the corona needle 112 is not attached (including the case where it is not attached correctly) (step 7).

When the determination unit 45 makes the above determination, the output unit 46 outputs the determination result (step 8). The output of the determination result by the output unit 46 can be performed in various forms such as screen display on the display unit 6, audio output, or lighting of a lamp provided at a predetermined position.

The user can also check the attachment/detachment state of the corona needle 112 at a desired timing. When the user performs a predetermined operation through the input unit 5 , the attachment/detachment confirmation reception unit 42 displays a button for instructing confirmation of the attachment/detachment state of the corona needle 112 on the screen of the display unit 6 . When the user presses this button to instruct confirmation of the attachment/detachment state of the corona needle 112 (step 11), the voltage application unit 43 applies the APCI voltage to the corona needle 112 (step 12) in the same manner as described above. The current measuring unit 44 measures the value of the current flowing through the conducting unit 116 (step 13). Then, the determination unit 45 checks whether the current value obtained by the measurement exceeds a predetermined threshold value (step 14). When the current value obtained by the current measuring unit 44 exceeds the threshold (YES in step 14), it is determined that the corona needle 112 is correctly attached (step 15). On the other hand, if the current value is equal to or less than the threshold value (NO in step 14), it is determined that the corona needle 112 is not attached (including the case where it is not attached correctly) (step 16). When the judgment unit 45 makes the above judgment, the output unit 46 outputs the result of the judgment (step 17).

Also, a process for checking the attaching/detaching state of the corona needle 112 can be added to the batch file used when measuring the sample.

When the user instructs the setting of the sample measurement conditions by a predetermined operation through the input unit 5, the measurement condition setting unit 47 sets the ionization conditions (the ionization method such as the ESI method or the APCI method, the value of the voltage applied during ionization, etc.). ), mass spectrometry conditions (measurement type such as MS scan measurement, SIM measurement, MS/MS scan measurement, MRM measurement, mass-to-charge ratio value (or range) used for these measurements, etc.) The screen is displayed on the display unit 6.

When the user completes the setting of each measurement condition (step 21), the measurement condition setting unit 47 checks whether the set ionization conditions include the APCI method (step 22). If it is not set to perform ionization by the APCI method (NO in step 22), create a method file describing the measurement conditions set by the user, and create a batch file for executing the method file. and save it in the storage unit 41 (step 25).

On the other hand, if it is set to perform ionization by the APCI method (YES in step 22), the user is asked to specify whether or not to confirm the attachment/detachment state of the corona needle 112 when performing measurement. If the user decides that it is not necessary to confirm the attachment/detachment state of the corona needle 112 (NO in step 23), a method file describing the measurement conditions set by the user is created, and the method file is executed. A batch file for this purpose is created and stored in the storage unit 41 (step 25).

If the user specifies to check the attachment/detachment state of the corona needle 112 (YES in step 23), a method file describing the measurement conditions set by the user is created, and furthermore, before execution of the method file A batch file is created in which a process for checking the attachment/detachment state of the corona needle 112 is added, and stored in the storage unit 41 (step 24).

After creating the batch file, when the user instructs to start measuring the sample (step 26), the measurement control unit 48 executes the batch file stored in the storage unit 41. If the batch file does not describe the process of confirming the attachment/detachment state of the corona needle 112 (NO in step 27), the sample is measured as it is (step 36).

On the other hand, if the batch file includes a process for checking the attachment/detachment state of the corona needle 112 (YES in step 27), the voltage application unit 43 applies the APCI voltage to the corona needle 112 (step 28), the current measuring unit 44 measures the value of the current flowing through the conducting unit 116 (step 29). Then, the determination unit 45 checks whether the current value obtained by the measurement exceeds a predetermined threshold value (step 30). When the current value obtained by the current measuring unit 44 exceeds the threshold value (step 30 YES), it is determined that the corona needle 112 is correctly attached (step 31), and the determination result is output. (step 32) and measurements are performed (step 36).

On the other hand, if the current value is equal to or less than the threshold value (NO in step 30), it is determined that the corona needle 112 is not attached (including the case where it is not attached correctly) (step 33), and the determination result is output. (step 34). When the determination unit 45 determines that the corona needle 112 is not attached, the execution of the batch file by the measurement control unit 48 is also stopped (step 35), and the user is asked to confirm the attachment state of the corona needle 112. A prompting screen is displayed on the display unit 6 .

In the dual ionization device, components contained in the liquid sample sprayed from the ESI probe 111 are sprayed onto the corona needle 112, and the sample components adhere to the surface of the corona needle 112. If the surface of the corona needle 112 is contaminated, the state of corona discharge will not be stable, resulting in variations in ionization efficiency. Therefore, it is necessary to periodically remove the discharge electrode from the ionization device and clean it. Further, when the ESI method is designated as an official method for ionizing sample components, it may be necessary to remove the corona needle 112 . After removing the corona needle 112 in this manner, the corona needle 112 must be attached when the sample components are to be ionized again by the APCI method. However, for example, when a user other than the person who removed the corona needle 112 performs the measurement, there is a possibility that the user may perform the measurement without noticing that the corona needle 112 has been removed. Then, since corona discharge does not occur, the sample components are not ionized, and the sample and time are lost.

On the other hand, in the mass spectrometry system 100 of the present embodiment, measurement is performed at the timing when the front door 311 is closed, at any timing when the user wants to check the attachment/detachment state of the corona needle 112, and at ionization by the APCI method. The attachment/detachment state of the corona needle 112 can be confirmed at the timing.

It is also conceivable to dispose a sensor for detecting attachment/detachment of the corona needle 112 in the needle attachment portion 115 in order to confirm the attachment state of the corona needle 112 . However, in the ionization chamber 11, heated gas may be blown to promote desolvation of the charged droplets, so the sensor is exposed to a high-temperature atmosphere. Also, various substances that may adhere to the surface of the corona needle 112 may also adhere to the sensor. Therefore, it is necessary to use an expensive sensor that operates stably at high temperatures and has sufficient resistance to chemical contamination. Furthermore, when contaminated with chemical substances, etc., not only the corona needle 112 but also the sensor for checking the mounting state of the corona needle 112 must be removed and cleaned.

On the other hand, in the mass spectrometry system 100 of the present embodiment, the power supply unit 2 used for applying the ESI voltage to the ESI probe 111 and applying the APCI voltage to the corona needle 112 is used to Since it is only necessary to measure the value of the current flowing through the current-carrying portion 116, it is possible to easily and inexpensively confirm the attachment/detachment state of the corona needle 112 without adding new hardware.

The above embodiment is just an example, and can be modified as appropriate in line with the spirit of the present invention.

In the above embodiment, the first housing 31 having the front door 311 is used, and when the sensor detects that the front door 311 is closed, the voltage application unit 43 applies the APCI voltage to the energization unit 116. Although the configuration is such that voltage is applied, other configurations can also be adopted. For example, using a first housing 31 that is detachable from the second housing 32 and has an opening at a position facing the ionization chamber 11 at a connection portion with the second housing 32, opening and closing the opening It is possible to employ a configuration provided with a sensor for detecting. In that case, the first housing 31 is removed from the second housing 32, and the corona needle 112 is attached and detached through an opening provided in the first housing 31. FIG. After that, the user attaches the first housing 31 to the second housing 32, and when the sensor detects that the opening of the first housing 31 is closed by the sensor, the voltage application unit 43 switches to the energizing unit. 116 to apply the APCI voltage.

In the above embodiment, the mass spectrometer 1 having a dual ionization device is used, but a mass spectrometer having an APCI device that performs only ionization by the APCI method can also be configured in the same manner as above. Further, although the mass spectrometer 1 of the above embodiment has a triple quadrupole configuration, mass spectrometers having other types of mass separation units can also have the same configuration as described above. Furthermore, in addition to mass spectrometers, ion analyzers such as ion mobility spectrometers can adopt the same configuration as described above.

Further, in the above-described embodiment, the corona needle 112 is operated at the timing when the front door 311 is closed, the timing at which the user wants to check the attachment/detachment state of the corona needle 112, and the timing at which the ionization measurement by the APCI method is performed. Although the configuration is such that it is possible to check the attachment/detachment state of each, it may be configured such that only one of these can be performed.

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

(Section 1)
A mass spectrometer according to an aspect of the present invention comprises
a probe for spraying a liquid sample;
a discharge electrode arranged at a position where the liquid sample is sprayed from the probe;
a discharge electrode mounting portion provided with a current-carrying portion for the discharge electrode and to which the discharge electrode is detachably mounted;
a voltage applying unit that applies a voltage to the current-carrying unit to cause corona discharge in the discharge electrode;
a current measuring unit that measures a current value flowing through the current-carrying unit while the voltage is being applied;
a determination unit that determines that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and an output unit that outputs a result of determination by the determination unit.

(Section 7)
An ionization device according to another aspect of the present invention comprises
a probe for spraying a liquid sample;
a discharge electrode arranged at a position where the liquid sample is sprayed from the probe;
a discharge electrode mounting portion provided with a current-carrying portion for the discharge electrode and to which the discharge electrode is detachably mounted;
a voltage applying unit that applies a voltage to the current-carrying unit to cause corona discharge in the discharge electrode;
a current measuring unit that measures a current value flowing through the current-carrying unit while the voltage is being applied;
a determination unit that determines that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and an output unit that outputs a result of determination by the determination unit.

(Section 8)
Yet another aspect of the present invention is an ionization method for ionizing a liquid sample by generating corona discharge in a discharge electrode provided at a position where the liquid sample is sprayed from a probe,
a step of applying a voltage to the discharge electrode to generate a corona discharge and measuring a current value flowing through a current-carrying portion to the discharge electrode;
determining that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and outputting the result of the determination.

In the mass spectrometer of item 1, the ionization apparatus of item 7, and the ionization method of item 8, when the corona discharge is generated in the discharge electrode, the value of the current flowing through the discharge electrode is lower than the value of the current flowing through the discharge electrode. A current value that cannot be reached when there is no electricity is set in advance as the threshold value. In the mass spectrometer of item 1, the ionization apparatus of item 7, and the ionization method of item 8, when a predetermined voltage for generating corona discharge is applied, the current value flowing through the electrode attachment portion is measured. do. At this time, if the discharge electrode is attached, current exceeding the threshold value flows, and if the discharge electrode is not attached, no current flows. In the mass spectrometer of item 1, the ionization apparatus of item 7, and the ionization method of item 8, the attachment/detachment state of the discharge electrode is determined based on the result of comparing the current value measured at this time with the threshold value, Since the result is output, the user can easily check the attachment/detachment state of the discharge electrode.

(Section 2)
In the ionization device according to item 1,
The threshold is 10 μA or more and 1 A or less.

Even if a voltage is applied without the discharge electrode attached, no current flows through the electrode attachment and the measured current value does not reach 10 μA. Also, normally, when a voltage within the range applied to the discharge electrode is applied during standby chemical ionization, a current exceeding 1 A does not flow through the electrode mounting portion. Therefore, in the ionization device of item 2, it is possible to correctly determine that the discharge electrode is not attached based on the fact that the current value is less than 10 μA. Also, based on the fact that the current value exceeds 1 A, it can be determined that there is an abnormality in the mounting state of the discharge electrode (for example, contact with the sampling cone).

(Section 3)
In the mass spectrometer according to item 1 or 2, further,
a first housing constituting an ionization chamber to which the discharge electrode is attached, the first housing having an opening at a position facing the ionization chamber;
a first control unit that operates the voltage application unit, the current measurement unit, and the determination unit in response to the closure of the opening;
Prepare.

(Section 4)
In the mass spectrometer according to item 3,
The first housing further includes a door that closes the opening.

(Section 5)
In the mass spectrometer according to item 3, further,
a second housing containing a mass spectrometer for mass-separating and detecting ions generated from the liquid sample,
The opening is provided in the connecting portion with the second housing.

In the ionization device of paragraph 3, after the user attaches or detaches the discharge electrode from the opening provided in the first housing, the user himself/herself gives an instruction when the opening is closed. It is possible to easily check the attachment/detachment state of the discharge electrode without having to The first housing can have an opening and a door for closing the opening, as described in the fourth item, for example. Alternatively, as described in item 5, the first housing has an opening at a connection portion with the second housing, and the opening is opened by attaching the first housing to the second housing. It can also be closed.

(Section 6)
In the mass spectrometer according to any one of items 1 to 5, further,
an attachment/detachment confirmation reception unit that accepts a predetermined input operation for confirming attachment/detachment of the discharge electrode;
a second control unit that operates the voltage application unit, the current measurement unit, and the determination unit when the attachment/detachment confirmation reception unit receives the predetermined input operation;
Prepare.

With the mass spectrometer in Section 6, the user can check the attachment/detachment state of the discharge electrode at any time.

DESCRIPTION OF SYMBOLS 100... Mass spectrometry system 1... Mass spectrometer 11... Ionization chamber 111... ESI probe 112... Corona needle 113... Desolvation tube 114... Heating block 115... Needle attachment part 116... Current-carrying part 12... First intermediate vacuum chamber 121... Ions Guide 122 Skimmer 13 Second intermediate vacuum chamber 131 Ion guide 14 Analysis chamber 141 Front quadrupole mass filter 142 Collision cell 143 Multipole ion guide 144 Rear quadrupole mass filter 145 Ion detector 2... Power supply unit 31... First housing 311... Front door 32... Second housing 33... Third housing 4... Control/processing unit 41... Storage unit 42... Attachment/detachment confirmation reception unit 43... Voltage application unit 44... Current Measurement section 45... Determination section 46... Output section 47... Measurement condition setting section 48... Measurement control section 5... Input section 6... Display section

Claims (8)

a probe for spraying a liquid sample;
a discharge electrode arranged at a position where the liquid sample is sprayed from the probe;
a discharge electrode mounting portion provided with a current-carrying portion for the discharge electrode and to which the discharge electrode is detachably mounted;
a voltage applying unit that applies a voltage to the current-carrying unit to cause corona discharge in the discharge electrode;
a current measuring unit that measures a current value flowing through the current-carrying unit while the voltage is being applied;
a determination unit that determines that the discharge electrode is attached when the current value exceeds a predetermined threshold;
A mass spectrometer comprising: an output unit that outputs a result of determination by the determination unit. The mass spectrometer according to claim 1, wherein the threshold is 10 µA or more and 1 A or less. a first housing constituting an ionization chamber to which the discharge electrode is attached, the first housing having an opening at a position facing the ionization chamber;
a first control unit that operates the voltage application unit, the current measurement unit, and the determination unit in response to the closing of the opening;
The mass spectrometer of claim 1, comprising: The first housing further comprises
4. The mass spectrometer according to claim 3, comprising a door closing said opening. moreover,
a second housing containing a mass spectrometer for mass-separating and detecting ions generated from the liquid sample,
4. The mass spectrometer according to claim 3, wherein said opening is provided in a connecting portion with said second housing. moreover,
an attachment/detachment confirmation reception unit that accepts a predetermined input operation for confirming attachment/detachment of the discharge electrode;
a second control unit that operates the voltage application unit, the current measurement unit, and the determination unit when the attachment/detachment confirmation reception unit receives the predetermined input operation;
The mass spectrometer of claim 1, comprising: a probe for spraying a liquid sample;
a discharge electrode arranged at a position where the liquid sample is sprayed from the probe;
a discharge electrode mounting portion provided with a current-carrying portion for the discharge electrode and to which the discharge electrode is detachably mounted;
a voltage applying unit that applies a voltage to the current-carrying unit to cause corona discharge in the discharge electrode;
a current measuring unit that measures a current value flowing through the current-carrying unit while the voltage is being applied;
a determination unit that determines that the discharge electrode is attached when the current value exceeds a predetermined threshold;
An ionization apparatus comprising: an output unit that outputs a result of determination by the determination unit. In an ionization method for ionizing a liquid sample by generating a corona discharge in a discharge electrode provided at a position where the liquid sample is sprayed from a probe,
a step of applying a voltage to the discharge electrode to generate a corona discharge and measuring a current value flowing through a current-carrying portion to the discharge electrode;
determining that the discharge electrode is attached when the current value exceeds a predetermined threshold;
and outputting the result of the determination.

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