WO2016002502A1 - Mass spectrometer and mass-spectrometry method - Google Patents

Abstract

This invention obtains appropriate mass-spectrometry results by performing mass spectrometry in a state in which ionization efficiency is increased. Using a voltage supplied by barrier power supplies (8, 9), an ionization unit (3) ionizes a sample. An ion-trapping unit (4b) captures ions from the sample ionized by the ionization unit (3), and a detection unit (6c) detects said ions. Using a voltage supplied by introduction power supplies (11, 12), the ions captured by the ion-trapping unit (4b) are introduced into the detection unit (6c) by an introduction unit (6b). During a first period, a control unit (16) switches the polarities of the voltage supplied to the ionization unit (3) and the voltage supplied to the introduction unit (6b), and during a second period that follows the first period, the control unit (16) controls the polarities of the voltage supplied to the ionization unit (3) and the voltage supplied to the introduction unit (6b) on the basis of the number of ions detected using the switched polarities.

Description

Mass spectrometer and mass spectrometry method

The present invention relates to a mass spectrometer and a mass spectrometry method. The present invention claims the priority of Japanese Patent Application No. 2014-138445 filed on July 4, 2014. For designated countries where weaving by reference is allowed, the contents described in the application are as follows: Is incorporated into this application by reference.

Patent Document 1 discloses a high-voltage power supply device capable of reducing cost and higher reliability than the prior art, and capable of switching the polarity of the output voltage at a relatively high speed, and a mass spectrometer using such a power supply device. Is disclosed.

International Publication Number WO2007 / 029327

The mass spectrometer performs analysis by ionizing a sample. Whether the sample is ionized positively or negatively depends on the type of the sample. For this reason, when ionizing a sample, depending on the sample, ionization efficiency may be poor and an appropriate mass analysis result may not be obtained.

In Patent Document 1, the voltage to be applied is switched depending on whether the analysis target is a positive ion or a negative ion. Therefore, depending on the analysis target, ionization efficiency may be poor and an appropriate mass analysis result may not be obtained. For example, a positive voltage is applied to an analyte to be positively ionized, and a negative voltage is applied to an analyte to be negatively ionized. Sometimes it is good.

Therefore, an object of the present invention is to provide a technique for performing mass analysis with higher ionization efficiency and obtaining appropriate mass analysis results.

The present application includes a plurality of means for solving at least a part of the above-described problems, and examples thereof are as follows. In order to solve the above problems, a mass spectrometer according to the present invention includes a first power source, an ionization unit that ionizes a sample with a voltage supplied from the first power source, and the sample ionized by the ionization unit. An ion trap unit that captures ions of the ion, a detection unit that detects ions, a second power source, and ions captured by the ion trap unit are supplied to the detection unit by a voltage supplied from the second power source. In the first period, the polarity of the voltage supplied to the ionization unit and the polarity of the voltage supplied to the introduction unit are switched in the first period, and based on the detected amount of ions in the switched polarity, the first And a control unit that controls the polarity of the voltage supplied to the ionization unit and the voltage supplied to the introduction unit in a second period following the period.

In the present invention, it is possible to perform mass analysis with higher ionization efficiency and obtain an appropriate mass analysis result. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is the figure which showed the block structural example of the mass spectrometer which concerns on 1st Embodiment. It is a flowchart explaining schematic operation | movement of a mass spectrometer. It is the figure which showed the example of the timing chart of a mass spectrometer. It is the figure which showed the example of the ion intensity | strength obtained from an ion detection part. It is the flowchart which showed the operation example of the mass spectrometer. It is the figure which showed the hardware structural example of the control part. It is the figure which showed the circuit example of the barrier power supply which concerns on 2nd Embodiment. It is the figure which showed the example of the timing chart of a mass spectrometer. It is the flowchart which showed the operation example of the mass spectrometer. It is the figure which showed the circuit example of the barrier power supply which concerns on 3rd Embodiment. It is a figure explaining the voltage waveform of the pulse voltage output from a barrier power supply. It is the figure which showed the example of the timing chart of a mass spectrometer. It is the flowchart which showed the operation example of the mass spectrometer. It is the figure which showed the example of a screen of the display apparatus which concerns on 4th Embodiment. It is the figure which showed the block structural example of the mass spectrometer which concerns on 5th Embodiment. It is the figure which showed the example of the timing chart of a mass spectrometer. It is the figure which showed the block structural example of the mass spectrometer which concerns on 6th Embodiment. It is the figure which showed the block structural example of the mass spectrometer which concerns on 7th Embodiment.

There is a mass spectrometer as a device for determining a component of a trace substance contained in a sample. In recent years, the market for mass spectrometers as on-site illegal drug and explosive detection devices is expanding. The mass spectrometer ionizes molecules in a sample to be analyzed, performs mass separation using one or both of an electric field and a magnetic field, and detects the separated ions with a detector. Generally, the polarity of ionization differs depending on the sample, such as illegal drugs are easily ionized and explosives are easily ionized.

There are several types of mass spectrometers depending on the application, such as a stationary type for quantitative analysis and a portable type for quick measurement on site. The stationary type is generally a system in which components of an analysis object are separated in an LC (liquid chromatograph) part and qualitative and quantitative analysis is performed in an MS (mass spectrometry) part. In the stationary type, a method using ESI (electrospray method) or an APCI (atmospheric pressure chemical ionization method) is mainly used as an ion source.

On the other hand, in the portable type, in recent years, a method using a barrier discharge, which is an ion source advantageous for miniaturization and high efficiency, has begun to be studied. In this barrier discharge, a pulsed or sinusoidal high voltage is applied through a dielectric barrier to a discharge portion having an atmospheric pressure close to the atmospheric pressure at which the sample is introduced to ionize molecules in the sample.

[First Embodiment]
FIG. 1 is a diagram illustrating a block configuration example of the mass spectrometer according to the first embodiment. As shown in FIG. 1, the mass spectrometer includes a capillary 1, a valve 2, an ionization unit 3, a mass analysis unit 4, a vacuum pump 5, an ion detection unit 6, a pressure detection unit 7, a barrier power source. 8, 9, switching units 10 and 13, introduction power supplies 11 and 12, CD (Conversion Dynode) power supply 14, scintillator power supply 15, control unit 16, and GUI (Graphical User Interface) 17. Yes. The mass spectrometer shown in FIG. 11 is a portable device that ionizes a sample by barrier discharge, for example.

Atmosphere and sample to be analyzed are introduced into the capillary 1. The atmosphere and the sample introduced into the capillary 1 are sent to the ionization unit 3 through the valve 2.

The valve 2 opens and closes and intermittently sends the air and sample introduced into the capillary 1 to the ionization unit 3.

The ionization unit 3 includes a dielectric container 3a and an electrode 3b. Air and a sample introduced into the capillary 1 are sent to the dielectric container 3a via the valve 2.

The electrode 3b is provided outside the dielectric container 3a and supplied with the voltage output from the switching unit 10. The electrode 3b causes a discharge current to flow in the dielectric container 3a by the voltage supplied from the switching unit 10 and ionizes the sample introduced from the capillary 1. That is, the ionization unit 3 causes a discharge current to flow through the atmosphere introduced from the capillary 1 by barrier discharge, and ionizes the sample (generates reactive ions).

The mass analysis unit 4 includes a chamber 4a, an ion trap unit 4b, an incap electrode 4c, and an end cap electrode 4d. The chamber 4a is a container for evacuating the inside, and has an ion trap portion 4b, an incap electrode 4c, and an end cap electrode 4d inside.

The ion trap part 4b supplements ions of a predetermined mass among the samples ionized by the ionization part 3. The ion trap unit 4b can change (sweep) a predetermined mass of ions to be trapped.

The incap electrode 4c and the end cap electrode 4d form an electric field and accumulate ions in the ion trap portion 4b.

The vacuum pump 5 exhausts the inside of the dielectric container 3a of the ionization unit 3, the chamber 4a of the mass analysis unit 4, and the chamber 6a of the ion detection unit 6.

The ion detection unit 6 includes a chamber 6a, an introduction unit 6b, and a detection unit 6c. The detection unit 6c includes a CD 6ca, a scintillator 6cb, and a photomultiplier tube 6cc.

The chamber 6a is a container for evacuating the inside, and has an introduction part 6b and a detection part 6c inside.

The introduction unit 6 b is, for example, a mesh (electrode), and a voltage is supplied from the switching unit 13. The introduction unit 6b attracts ions captured by the ion trap unit 4b by the voltage supplied from the switching unit 13, and introduces the ions into the detection unit 6c.

The CD 6ca of the detection unit 6c emits secondary electrons corresponding to the amount of ions introduced by the introduction unit 6b. The scintillator 6cb converts secondary electrons emitted by the CD 6ca into light. The photomultiplier tube 6cc amplifies the light converted by the scintillator 6cb and converts it into an electrical signal. That is, ions trapped (captured) by the ion trap section 4b are introduced into the detection section 6c by the introduction section 6b. Then, the detection unit 6c detects the amount of ions captured by the ion trap unit 4b. The electrical signal of the amount of ions detected by the detection unit 6 c is output to the control unit 16.

The pressure detector 7 detects the pressure in the dielectric container 3a and the chambers 4a and 6a.

The barrier power supplies 8 and 9 output a pulse voltage for causing discharge in the dielectric container 3a. The barrier power supply 8 outputs a positive pulse voltage, for example, a pulse voltage of “+3 kV”. The barrier power supply 9 outputs a negative pulse voltage, for example, a pulse voltage of “−3 kV”.

The switching unit 10 outputs one of the pulse voltages output from the barrier power supplies 8 and 9 to the electrode 3b under the control of the control unit 16. That is, either positive or negative pulse voltage is supplied to the electrode 3 b of the ionization unit 3.

The introduction power supplies 11 and 12 output a voltage for introducing ions from the ion trap section 4b to the detection section 6c. The introduction power supply 11 outputs a positive voltage, for example, a voltage of “+1 kV”. The introduction power supply 12 outputs a negative voltage, for example, a voltage of “−1 kV”.

The switching unit 13 outputs one of the voltages output from the introduction power supplies 11 and 12 to the introduction unit 6b under the control of the control unit 16. In other words, either positive or negative voltage is supplied to the introduction part 6 b of the ion detection part 6.

CD power supply 14 supplies voltage to CD6ca. For example, the CD power source 14 supplies a voltage of “−5 kV” to the CD 6 ca.

The scintillator power supply 15 supplies a voltage to the scintillator 6cb. For example, the scintillator power supply 15 supplies a voltage of “+5 kV” to the scintillator 6 cb.

The control unit 16 controls the overall operation of the mass spectrometer. For example, the control unit 16 controls the switching operation of the switching units 10 and 13 based on the amount of ions detected by the detection unit 6c. Moreover, the control part 16 controls the output timing of the voltage of CD power supply 14 and the scintillator power supply 15, for example. Moreover, the control part 16 controls operation | movement of the valve | bulb 2, the ionization part 3, the mass analysis part 4, the vacuum pump 5, the ion detection part 6, and the pressure detection part 7, for example.

The GUI 17 accepts an operation from a user, for example, or displays predetermined information on a display device.

FIG. 2 is a flowchart for explaining the schematic operation of the mass spectrometer. For example, when the user gives an instruction to start analyzing a sample, the mass spectrometer executes the following flowchart. It is assumed that air and a sample are introduced into the capillary 1.

First, the control unit 16 closes the valve 2 (step S1).

Next, the control unit 16 evacuates the dielectric container 3a and the chambers 4a and 6a with the vacuum pump 5 to make the pressure low (step S2). For example, the control unit 16 sets the inside of the dielectric container 3 a to “100 Pa” and the inside of the chambers 4 a and 6 a to “0.1 Pa” by the vacuum pump 5.

Next, the control unit 16 opens the valve 2 (step S3). As a result, the atmosphere and the sample are introduced from the capillary 1 into the dielectric container 3a.

Next, after opening the valve 2 in step S3, the control unit 16 performs barrier discharge when the inside of the dielectric container 3a reaches a predetermined atmospheric pressure (for example, a low pressure such as 1000 Pa) (step S4). For example, the control unit 16 controls the switching unit 10 to output one voltage of the barrier power supplies 8 and 9 to the electrode 3b and perform barrier discharge (the polarity control of the voltage output to the electrode 3b is described below. To do). The controller 16 performs barrier discharge in the dielectric container 3a to ionize the introduced low-pressure atmosphere (generate reaction ions), and ionize the sample with the reaction ions.

Next, the control unit 16 closes the bulb 2 after the start of the barrier discharge (step S5). Thereby, unnecessary air is discharged into the dielectric container 3a and the chambers 4a and 6a by the vacuum pump 5. The sample ionized in the dielectric container 3a is introduced into the ion trap portion 4b and accumulated.

Next, the control unit 16 introduces the ions of the sample accumulated in the ion trap unit 4b into the detection unit 6c through the introduction unit 6b, and detects the mass of the ions (step S6). For example, the control unit 16 controls the switching unit 13 to output one voltage of the introduction power supplies 11 and 12 to the introduction unit 6b, introduce ions accumulated in the ion trap unit 4b to the detection unit 6c, and (The polarity control of the voltage output to the introduction unit 6b will be described below). Thereby, the control part 16 can detect the drug etc. which are contained in the sample.

As will be described below, the mass spectrometer has two phases, a preamble period T1 and a measurement period T2. The mass spectrometer performs one or more of the above schematic operations in each of the two phases. When performing two or more of the schematic operations described above, the mass spectrometer proceeds to the process of step S3 after the process of step S6.

FIG. 3 is a diagram showing an example of a timing chart of the mass spectrometer. As shown by the one-dot chain line in FIG. 3, the mass spectrometer has two phases of a preamble period T1 and a measurement period T2. In the preamble period T1, the mass spectrometer has a combination of voltage polarity for barrier discharge and ion introduction (a voltage polarity applied to the electrode 3b and a voltage polarity applied to the introduction portion 6b). Determine if ionization efficiency is best. The mass spectrometer detects the mass of the sample in the measurement period T2 by a combination of the barrier discharge determined in the preamble period T1 and the voltage polarity of ion introduction.

The waveform W1 shown in FIG. 3 shows the on / off timing of the vacuum pump 5. The vacuum pump 5 does not exhaust when “OFF” shown in the waveform W1 and exhausts when “ON”.

The waveform W2 indicates the opening / closing timing of the valve 2. The valve 2 closes the valve by “closed” shown in the waveform W2, and opens the valve by “open”.

The waveform W3 indicates the timing of the pulse voltage that the switching unit 10 outputs to the electrode 3b of the ionization unit 3. The switching unit 10 does not output the positive and negative pulse voltages output from the barrier power supplies 8 and 9 to the electrode 3b when “OFF” shown in the waveform W3. The switching unit 10 outputs a positive pulse voltage output from the barrier power supply 8 to the plurality of electrodes 3b when “positive” shown in the waveform W3. The switching unit 10 outputs a negative pulse voltage output from the barrier power supply 8 to the plurality of electrodes 3b when “negative” shown in the waveform W3. Note that “+3 kV” shown in the measurement period T2 of the waveform W3 indicates that the switching unit 10 outputs a positive pulse voltage to the electrode 3b, and is a specific value.

Waveform W4 indicates the application timing of the voltage output from the CD power source 14 to CD6ca. The CD power supply 14 does not output a voltage to the CD6ca when “OFF” shown in the waveform W4, and outputs a voltage of “−5 kV” to the CD6ca when “−5 kV”, for example.

Waveform W5 shows the timing of the voltage that the scintillator power supply 15 outputs to the scintillator 6cb. The scintillator power supply 15 does not output a voltage to the scintillator 6cb when “OFF” shown in the waveform W5, and outputs a voltage of “+5 kV” to the scintillator 6cb when “+5 kV”, for example.

Waveform W6 indicates the timing of the voltage that the switching unit 13 outputs to the introduction unit 6b. The switching unit 13 does not output positive and negative voltages output from the introduction power supplies 11 and 12 to the introduction unit 6b when “OFF” shown in the waveform W6. The switching unit 13 outputs a positive voltage output from the introduction power supply 11 to the introduction unit 6b when “positive” shown in the waveform W6. The switching unit 13 outputs a negative voltage output from the introduction power supply 11 to the introduction unit 6b when “negative” shown in the waveform W6. Note that “−1 kV” shown in the measurement period T2 of the waveform W6 indicates that the switching unit 13 outputs a negative voltage to the introduction unit 6b, and is a specific value.

Waveform W7 shows the timing for detecting the light from the photomultiplier tube 6cc. The photomultiplier tube 6cc does not detect light when “OFF” shown in the waveform W7, and detects light when “ON”.

Waveform W8 indicates the state of atmospheric pressure in the dielectric container 3a and the chambers 4a and 6a. The atmospheric pressure in the dielectric container 3a and the chambers 4a and 6a rises and falls according to the opening and closing of the valve 2 indicated by the waveform W2.

The vacuum pump 5 starts evacuating the dielectric container 3a and the chambers 4a and 6a at time t1 shown in FIG. The vacuum pump 5 evacuates the dielectric container 3a and the chambers 4a and 6a after the start of evacuation until the mass analysis is completed, as indicated by “ON” of the waveform W1. When the vacuum pump 5 starts evacuation, the air pressure in the dielectric container 3a and the chambers 4a and 6a decreases (the degree of vacuum increases) as indicated by a waveform W8.

When the degree of vacuum of the dielectric container 3a and the chambers 4a and 6a reaches the threshold value th shown in the waveform W8, the valve 2 is opened for a certain period as shown in the waveform W2 at times t2 and t3. When the valve 2 is opened, the degree of vacuum of the dielectric container 3a and the chambers 4a and 6a is lowered. During this period, air and a sample are introduced from the capillary 1 into the dielectric container 3a.

The valve 2 is closed after time t3, and the inside of the dielectric container 3a and the chambers 4a and 6a is evacuated again by the vacuum pump 5. As a result, the degree of vacuum of the dielectric container 3a and the chambers 4a and 6a is increased again as shown at time t3 to time t6 of the waveform W8.

The valve 2 repeats the operation of opening for a certain period and then closing when the vacuum degree of the dielectric container 3a and the chambers 4a and 6a reaches the threshold th, as shown by the waveforms W2 and W8. Then, air and a sample are introduced from the capillary 1 into the dielectric container 3a.

The switching unit 10 outputs a pulse voltage to the electrode 3b from the second half of the “open” period of the valve 2 to the first half of the “closed” period, as indicated by the waveform W3 of the preamble period T1. Thereby, barrier discharge is performed in the dielectric container 3 a of the ionization unit 3. The sample ions ionized by the barrier discharge are trapped in the ion trap portion 4b.

Barrier discharge with positive and negative polarity voltages is performed in the preamble period T1, as shown by the waveform W3. In the measurement period T2, barrier discharge is performed with the polarity voltage determined in the preamble period T1. For example, in the measurement period T2 of FIG. 3, an example (+3 kV) in which a positive polarity voltage is determined is shown.

The switching unit 13 outputs a voltage to the introduction unit 6b for a certain period after the end of the barrier discharge (after the completion of the voltage application to the electrode 3b) as indicated by the waveform W6 at times t4 and t5. Thereby, the ion trapped by the ion trap part 4b is introduce | transduced into the detection part 6c by the introduction part 6b.

The ion introduction by the positive and negative polarity voltages is performed in the preamble period T1, as shown by the waveform W6. In the measurement period T2, ion introduction is performed with the polarity voltage determined in the preamble period T1. For example, in the measurement period T2 in FIG. 3, an example (−1 kV) in which a negative polarity voltage is determined is shown.

The CD power supply 14 outputs a voltage to the CD6ca for a certain period after the end of the barrier discharge, as indicated by a waveform W4 at times t4 and t5. Similarly, the scintillator power supply 15 outputs a voltage to the scintillator 6cb for a certain period after the end of the barrier discharge, as indicated by a waveform W5 at times t4 and t5. Then, the photomultiplier tube 6cc detects light after the end of the barrier discharge, as indicated by the waveform W7 at times t4 and t5.

The mass spectrometer repeats the operation described above when the degree of vacuum of the dielectric container 3a and the chambers 4a and 6a again exceeds the threshold th as shown by the waveform W8 at time t6.

The ion trap unit 4b sweeps the mass of ions to be captured within a certain period from time t4 to time t5. Therefore, from the photomultiplier tube 6cc, the result of the amount of ions (ion intensity) for each swept mass is obtained.

FIG. 4 is a diagram showing an example of ion intensity obtained from the ion detector. As described above, the ion trap unit 4b sweeps the mass of ions to be captured. For example, the ion trap unit 4b sweeps the mass of ions to be captured from the left side (small mass) to the right side (large mass) of the horizontal axis in FIG.

Here, it is assumed that substances A, B, and C are included in the sample. In this case, as shown in FIG. 4, the ionic strength in the masses of the substances A, B, and C increases (the amount of ions detected by the ion detector 6 increases). Therefore, the control part 16 can determine the substance contained in a sample by measuring the ion intensity | strength of the ion with respect to each mass captured by the ion trap part 4b.

Returning to the explanation of FIG. In the preamble period T1, the control unit 16 controls the switching unit 10 to switch the polarity of the pulse voltage output from the barrier power supplies 8 and 9 to the electrode 3b. In addition, the control unit 16 controls the switching unit 13 in the preamble period T1 to switch the polarity of the voltage output from the introduction power supplies 11 and 12 to the introduction unit 6b.

For example, the control unit 16 sets the polarity of the voltage output from the barrier power supplies 8 and 9 and the introduction power supplies 11 and 12 in the preamble period T1, as indicated by dotted line frames D1 to D4 in FIG. Switching between four combinations of negative and positive, positive and positive, and negative and positive.

When all the combinations of the voltage polarities of the barrier power supplies 8 and 9 and the introduction power supplies 11 and 12 are switched, the control unit 16 performs measurement following the preamble period T1 based on the detected amount of ions (ion intensity) in each switched polarity. In the period T2, the polarity of the voltage output to the electrode 3b and the introduction part 6b is determined.

For example, the control unit 16 integrates the ion intensity output from the ion detection unit 6 in each voltage polarity combination of the dotted line frames D1 to D4 shown in FIG. For example, the ionic strength as shown in FIG. 4 is obtained in the combination of the voltage polarities of the dotted line frames D1 to D4 shown in FIG. 3 (the peak as shown in FIG. 4 does not appear depending on the combination of the voltage polarities). The control unit 16 integrates the ion intensity obtained in each of the dotted line frames D1 to D4. The control unit 16 determines whether or not the integrated value of each ion intensity in the dotted line frames D1 to D4 exceeds a predetermined threshold, and determines a combination of voltage polarities of the ion intensity exceeding the predetermined threshold. Then, the control unit 16 performs mass analysis of the sample in the measurement period T2 with the determined voltage polarity.

For example, it is assumed that the integrated ion intensity exceeds a predetermined threshold in the combination of voltage polarities in the dotted frame D1 shown in FIG. In this case, the control unit 16 sets the voltage polarity of the barrier discharge to “positive” (shown as “+3 kV” in FIG. 3), as indicated by the dotted frames D5 and D6 in the measurement period T2 in FIG. The voltage polarity of the introduction is set to “negative” (shown as “−1 kV” in FIG. 3), and mass analysis of the sample is performed in the measurement period T2.

As described above, the polarity of the voltage output from the barrier power sources 8 and 9 and the introduction power sources 11 and 12 is switched because there are substances having different ionization efficiencies depending on the combination of the barrier discharge and the voltage polarity of the ion introduction. For example, even when a positive voltage is applied to the electrode 3b, depending on the substance, there are substances that are ionized into positive ions and substances that are ionized into negative ions. More specifically, a combination of the voltage polarity of the barrier discharge and the voltage polarity of the ion introduction yields the ion intensity as shown in FIG. 4, but the combination of the voltage polarity as shown in FIG. This is because the ionic strength of the substances A, B, and C may not show a large peak as shown in FIG.

Note that the operation of mass spectrometry in the measurement period T2 is the same as the operation described in the preamble period T1. However, in the measurement period T2, mass analysis of the sample is performed by barrier discharge and ion introduction having the voltage polarity determined in the preamble period T1. Further, the control unit 16 does not integrate the ion amount output from the ion detection unit 6 as in the preamble period T1, and stores the ion amount for each mass in a storage device such as a memory. For example, the control unit 16 stores data as illustrated in FIG. 4 in the storage device. And the control part 16 determines the substance contained in the sample from the mass with much ion content. For example, when data as shown in FIG. 4 is obtained in the measurement period T2, the control unit 16 determines that the sample contains substances A, B, and C.

In addition, the mass spectrometer may perform mass spectrometry a plurality of times in the measurement period T2 in order to obtain an appropriate mass analysis result. For example, in FIG. 3, as shown by dotted line frames D5 and D6, the mass spectrometer performs mass analysis a plurality of times.

In addition, a plurality of combinations of voltage polarities determined in the preamble period T1 may be obtained. For example, there may be a plurality of integral values of ion intensity exceeding a predetermined threshold. For example, the integrated value of the ion intensity may exceed a predetermined threshold in dotted line frames D1 and D3 shown in FIG.

In this case, the control unit 16 performs mass analysis of the sample in the measurement period T2 with the combination of the obtained plurality of voltage polarities. For example, when there are two combinations of voltage polarities in which ions are detected (for example, when there are voltage polarities of dotted line frames D1 and D3), the control unit 16 combines two voltage polarities in the measurement period T2. To perform mass spectrometry (for example, mass spectrometry is performed with two voltage polarities of dotted line frames D1 and D3). In addition, when ions are not detected in the preamble period T1, the control unit 16 may perform the preamble period T1 a plurality of times or terminate the measurement as it is.

Further, although the control unit 16 determines the combination of voltage polarities depending on whether or not the integrated value of the ion intensity exceeds a predetermined threshold value, the present invention is not limited to this. For example, the control unit 16 determines the combination of voltage polarities having the largest ion intensity integral value among the ion intensity integral values in each of the dotted line frames D1 to D4 shown in FIG. Then, the control unit 16 may perform mass analysis of the sample in the measurement period T2 with a combination of voltage polarities having the largest integral value of ion intensity. In this case, there is one voltage polarity combination to be determined.

Further, the control unit 16 does not integrate the ion intensity, for example, depending on whether or not the largest ion intensity exceeds a predetermined threshold in each combination of voltage polarities of the dotted line frames D1 to D4 shown in FIG. A combination of voltage polarities may be determined. For example, it is assumed that the ion intensity shown in FIG. 4 is obtained in the dotted frame D1. It is assumed that the ionic strength of the substance B in FIG. 4 exceeds a predetermined threshold value. In this case, the control unit 16 determines the voltage polarity (barrier discharge “positive”, ion introduction “negative” voltage polarity) of the dotted frame D1.

FIG. 5 is a flowchart showing an operation example of the mass spectrometer. For example, when a sample is introduced into the capillary 1 and an instruction to start analysis is given from the user via the GUI 17, the mass spectrometer executes the processing of the flowchart shown in FIG. 5. Steps S11 to S18 correspond to, for example, processing in the preamble period T1, and steps S22 to S29 correspond to processing in the measurement period T2. Steps S19 to S21 may be performed either at the end of the preamble period T1 or at the beginning of the measurement period T2.

First, the control unit 16 outputs a positive pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge +), and outputs a negative voltage to the introduction unit 6b (ion introduction −). Is switched (step S11).

Next, the ion detector 6 detects ions in each mass (in the swept mass) at the voltage applied in step S11 (step S12). The control unit 16 integrates the ion amount at each mass detected by the ion detection unit 6.

Next, the control unit 16 outputs a negative pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge −), and outputs a negative voltage to the introduction unit 6b (ion introduction −). 13 is controlled (step S13).

Next, the ion detector 6 detects ions at each mass at the voltage applied in step S13 (step S14). The control unit 16 integrates the ion amount at each mass detected by the ion detection unit 6.

Next, the control unit 16 outputs a positive pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge +), and outputs a positive voltage to the introduction unit 6b (ion introduction +). 13 is controlled (step S15).

Next, the ion detector 6 detects ions at each mass at the voltage applied in step S15 (step S16). The control unit 16 integrates the ion amount at each mass detected by the ion detection unit 6.

Next, the control unit 16 outputs a negative pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge −), and outputs a positive voltage to the introduction unit 6b (ion introduction +). 13 is controlled (step S17).

Next, the ion detector 6 detects ions at each mass at the voltage applied in step S17 (step S18). The control unit 16 integrates the ion amount at each mass detected by the ion detection unit 6.

Next, the controller 16 determines whether or not ions are detected by the ion detector 6 (step S19). For example, the control unit 16 determines whether or not the ion amount integrated in steps S12, S14, S16, and S18 exceeds a predetermined threshold value. When it determines with the control part 16 having detected the ion (in the case of "Yes" in S19), it transfers to the process of step S21. When it determines with the control part 16 having not detected ion (in the case of "No" in S19), it transfers to the process of step S20. In addition, the control part 16 acquires the combination of the voltage polarity which was able to detect ion, when it determines with having detected ion.

When it is determined in step S19 that the ions have not been detected (“No” in S19), the control unit 16 determines whether or not the processing of the preamble period T1 has been performed a predetermined number of times (step S20). That is, when the control unit 16 cannot detect ions, the control unit 16 performs processing of the preamble period T1 until a predetermined number of times is reached. When it is determined that the process of the preamble period T1 has been performed a predetermined number of times (in the case of “Yes” in S20), the control unit 16 ends the mass spectrometry process. If the control unit 16 determines that the process of the preamble period T1 is not performed a predetermined number of times (in the case of “No” in S20), the control unit 16 proceeds to the process of step S11.

If it is determined in step S19 that ions have been detected ("Yes" in S19), the control unit 16 determines whether or not there is only one combination of voltage polarities in which ions can be detected (step S21). . If the control unit 16 determines that the number of combinations of voltage polarities that can detect ions is one (“Yes” in S21), the control unit 16 proceeds to the process of step S22. If the control unit 16 determines that the number of combinations of voltage polarities that can detect ions is not one (a plurality), the process proceeds to step S26.

When it is determined in step S21 that there is only one combination of voltage polarities in which ions can be detected ("Yes" in S21), the control unit 16 has one voltage polarity acquired in step S19. The combination is set to be output from the switching units 10 and 13 in the measurement period T2 (step S22).

Next, the ion detector 6 detects ions at each mass (step S23). The ion amount (for example, data as shown in FIG. 4) of ions at each mass detected by the ion detection unit 6 is stored in a storage device such as a memory by the control unit 16.

Next, the control unit 16 determines whether or not mass spectrometry has been performed a predetermined number of times (step S24). When it is determined that the mass spectrometry has been performed a predetermined number of times (“Yes” in S24), the control unit 16 proceeds to the process of step S25. When it is determined that the mass spectrometry has not been performed a predetermined number of times (“No” in S24), the control unit 16 proceeds to the process of step S22.

When it is determined in step S24 that the mass spectrometry has been performed a predetermined number of times (in the case of “Yes” in S24), the control unit 16 outputs the ion amount stored in the storage device in step S23 (step S25). For example, the control unit 16 outputs the amount of ions at each mass (for example, a graph as shown in FIG. 4) to the display device.

When it is determined in step S21 that there are a plurality of combinations of voltage polarities in which ions can be detected (“No” in S21), the control unit 16 combines a plurality of voltage polarities acquired in step S19. Is set to be output from the switching units 10 and 13 during the measurement period T2 (step S26).

Next, the ion detector 6 detects ions at each mass in each combination of a plurality of voltage polarities (step S27). The ion amount (for example, data as shown in FIG. 4) of ions at each mass detected by the ion detection unit 6 is stored in a storage device such as a memory by the control unit 16.

Next, the control unit 16 determines whether or not mass spectrometry has been performed a predetermined number of times (step S28). When it is determined that the mass spectrometry has been performed a predetermined number of times (“Yes” in S28), the control unit 16 proceeds to the process of step S29. When it is determined that the mass analysis has not been performed a predetermined number of times (“No” in S28), the control unit 16 proceeds to the process of step S26.

When it is determined in step S28 that the mass spectrometry has been performed a predetermined number of times (“Yes” in S28), the control unit 16 outputs the ion amount stored in the storage device in step S27 (step S29). For example, the control unit 16 outputs the amount of ions at each mass (for example, a graph as shown in FIG. 4) to the display device.

FIG. 6 is a diagram illustrating a hardware configuration example of the control unit. The control unit 16 and the GUI 17 include, for example, an arithmetic device 21 such as a CPU (Central Processing Unit), a main storage device 22 such as a RAM (Random Access Memory), an HDD (Hard Disk Drive), and the like as shown in FIG. Auxiliary storage device 23, a communication interface (I / F) 24 for connecting to a communication network by wire or wireless, an input device 25 such as a mouse, keyboard, touch sensor or touch panel, and a display device 26 such as a liquid crystal display. And a read / write device 27 that reads / writes information from / to a portable storage medium such as a DVD (Digital Versatile Disk).

For example, the function of the control unit 16 is realized by the arithmetic device 21 executing a predetermined program loaded from the auxiliary storage device 23 or the like to the main storage device 22. The GUI 17 is realized, for example, when the arithmetic device 21 uses the input device 25. Further, the GUI 17 is realized, for example, when the arithmetic device 21 uses the display device 26. Communication between the control unit 16 and other devices is realized by the arithmetic device 21 using the communication I / F 24, for example.

The predetermined program may be installed from, for example, a storage medium read by the read / write device 27, or may be installed from a network via the communication I / F 24.

Further, some or all of the functions of the control unit 16 and the GUI 17 may be realized by, for example, an ASIC (Application Specific Integrated Circuit) including an arithmetic device, a storage device, a drive circuit, and the like.

As described above, the control unit 16 of the mass spectrometer switches the polarity of the voltage output from the barrier power supplies 8 and 9 and the introduction power supplies 11 and 12 in the preamble period T1, and based on the detected amount of ions in the switched polarity. In the measurement period T2 following the preamble period T1, the polarity of the voltage output from the barrier power supplies 8 and 9 and the introduction power supplies 11 and 12 is controlled. Thereby, the control part 16 can determine the combination of voltage polarity with higher ionization efficiency, can perform mass analysis with the determined voltage polarity, and can obtain an appropriate mass spectrometry result.

Further, the control unit 16 can realize the shortening of the measurement period T2 and the stabilization of the measurement by detecting ions in the measurement period T2 with the combination of the voltage polarities determined in the preamble period T1.

Further, the control unit 16 has four polarities of the voltages output from the barrier power supplies 8 and 9 and the introduction power supplies 11 and 12 in the preamble period T1, which are positive and negative, negative and negative, positive and positive, and negative and positive. By switching in combination, for example, it is possible to detect various types of samples such as drugs, explosives, and chemical substances.

Further, since the sample is ionized by the barrier discharge, the mass spectrometer can perform mass analysis with higher ionization efficiency even on-site and obtain an appropriate mass analysis result.

In the above description, in the preamble period T1, the combination of the voltage polarity of the electrode 3b and the voltage polarity of the introduction portion 6b is performed in the order of steps S11, S13, S15, and S17. However, the present invention is not limited to this. The same effect can be obtained even in the order.

Further, the control unit 16 may switch the polarity of the voltage supplied to the CD 6ca. For example, the control unit 16 may supply the CD 6ca with a voltage having the same polarity as the voltage supplied to the introduction unit 6b. This also provides the same effect.

For example, when the target of the sample to be subjected to mass spectrometry is determined in advance, ion detection may be performed with a predetermined voltage polarity that is smaller than the four voltage polarities. For example, many illegal drugs are positively ionized. In this case, for example, the voltage polarity with the barrier discharge “positive” and the ion introduction “negative” and the voltage polarity with the barrier discharge “negative” and the ion introduction “negative” with two voltage polarities, Ion detection may be performed.

In the above description, the ion detection is divided into the preamble period T1 and the measurement period T2. However, the present invention is not limited to this. For example, the same effect can be obtained even if the combinations of four voltage polarities in the preamble period T1 are continued as they are in the measurement period T2. More specifically, the mass spectrometer may repeat only the processing of the preamble period T1 shown in FIG. 3 a predetermined number of times.

Further, the control unit 16 may fix the voltage polarity of the CD 6ca by fixing the voltage of the introduction unit 6b to either positive or negative voltage. Alternatively, the introduction unit 6b, the introduction power supplies 11 and 12, and the switching unit 13 may be omitted, and the control unit 16 may change the voltage polarity of the CD 6ca. This also provides the same effect.

[Second Embodiment]
In the second embodiment, the frequency of the pulse voltage output to the electrode 3b of the ionization unit 3 is changed. Below, a different part from 1st Embodiment is demonstrated, and the part same as 1st Embodiment is demonstrated using the code | symbol of 1st Embodiment.

FIG. 7 is a diagram showing a circuit example of the barrier power supply according to the second embodiment. As shown in FIG. 7, the barrier power supply 8 includes a drive unit 31, a switching unit 32, a high voltage module 33, and a capacitor C3.

The driving unit 31 includes an amplifier A1, resistors R1 to R3, a transistor Tr1, and a capacitor C1. The drive unit 31 changes the voltage of the primary side terminal (terminal connected to the emitter of the transistor Tr1) of the transformer T1 of the high-voltage module 33 according to the voltage input to the non-inverting input terminal of the amplifier A1. Controls the output voltage amplitude.

The switching unit 32 includes a capacitor C2 and a transistor Tr2. A clock is input to the gate of the transistor Tr2 via the capacitor C2. The clock is a repetitive pulse of a rectangular wave, and has a high level period (Ton) and a low level period (Toff) as shown in FIG. The clock frequency f is expressed by the following equation (1) using “Ton” and “Toff”.

F = 1 / (Ton / Toff) (1)

The clock is output from the control unit 16, for example. The control unit 16 varies the frequency of the pulse voltage output from the barrier power supply 8 by changing “Ton” and “Toff” of the clock output to the barrier power supply 8. The clock duty ratio D is expressed by the following equation (2).

D = {Ton / (Ton + Toff)} × 100 (2)

In the flyback type high-voltage circuit, during the “Ton” period, a current flows from the primary side terminal tp1 of the transformer T1 to the transistor Tr2, and the resonance capacitor C3 is charged. In the “Toff” period, the charge charged in the capacitor C3 flows toward the primary side terminal tp1 of the transformer T1.

The high voltage module 33 includes a transformer T1 and resistors R4 and R5. The voltage on the primary side of the transformer T1 changes due to a change in current flowing in the “Ton” period and the “Toff” period. The voltage on the primary side of the transformer T1 is transmitted to the secondary side of the transformer T1. A pulse voltage corresponding to the winding ratio is output from the secondary side of the transformer T2.

That is, the barrier power supply 8 can vary the amplitude of the pulse voltage to be output according to the voltage input to the drive unit 31. Further, the barrier power supply 8 can vary the frequency of the output pulse voltage according to the frequency of the clock input to the switching unit 32. The barrier power supply 9 also has a circuit similar to that shown in FIG. 7, but the portion that outputs a negative pulse voltage is different.

Depending on the substance, the ionization efficiency varies depending on the frequency of the pulse voltage supplied to the electrode 3b. That is, the optimum pulse frequency varies depending on the sample. For this reason, when it is not known what components are contained in the sample, it is advantageous to perform ionization at a plurality of pulse frequencies in terms of increasing ionization efficiency and improving ion detection sensitivity.

FIG. 8 is a diagram showing an example of a timing chart of the mass spectrometer. In FIG. 8, a different part from FIG. 3 is demonstrated.

The barrier power supplies 8 and 9 vary the frequency of the pulse voltage output to the switching unit 10 according to the frequency of the clock output from the control unit 16. For example, the barrier power supplies 8 and 9 output pulse voltages having three types of frequencies of “10 kHz”, “20 kHz”, and “5 kHz”.

A waveform W11 shown in FIG. 8 indicates a waveform of a positive pulse voltage output from the switching unit 10 to the electrode 3b. As shown in the waveform 11, pulse voltages having three kinds of frequencies are supplied to the electrode 3b.

A waveform W12 shown in FIG. 8 shows a waveform of a negative pulse voltage output from the switching unit 10 to the electrode 3b. As shown in the waveform 12, the electrode 3b is supplied with pulse voltages having three kinds of frequencies.

In addition, the ion trap part 4b sweeps mass in each frequency of a pulse voltage. The control unit 16 also outputs pulse voltages having a plurality of frequencies in each barrier discharge even in the measurement period 2. For example, in the example of FIG. 8, the control unit 16 outputs pulse voltages of three types of frequencies even in each barrier discharge in the measurement period 2. Further, in the measurement period 2, the control unit 16 stores, for example, the amount of ions having the highest ionization efficiency among the amounts of ions obtained at each frequency in the storage device.

FIG. 9 is a flowchart showing an operation example of the mass spectrometer. In FIG. 9, the same processes as those in FIG. In FIG. 9, processing different from FIG. 5 will be described.

In step S11, the control unit 16 outputs a positive pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge +), and outputs a negative voltage to the introduction unit 6b (ion introduction −). , 13 is controlled, and in step S11a, control is performed so that pulse voltages having different frequencies are output from the barrier power supply 8. Thereby, for example, in the barrier discharge of the dotted frame D1 shown in FIG. 8, pulse voltages having different frequencies as shown in the waveform W11 are output to the electrode 3b.

The controller 16 also controls the barrier power supplies 8 and 9 so that pulse voltages having different frequencies are output to the electrode 3b in steps S13a, 15a, and 17a as described above.

The controller 16 controls the barrier power supplies 8 and 9 so that pulse voltages having different frequencies are output to the electrode 3b in steps S22a and S26a. That is, the control unit 16 controls the barrier power supplies 8 and 9 so that pulse voltages having different frequencies are output to the electrode 3b even during the measurement period T2.

The ion detector 6 detects ions in each mass (swept mass) at each frequency in steps S23a and S27a. For example, the control unit 16 stores, in the storage device, the ion amount of the frequency with the highest ionization efficiency among the ion amounts in each mass at each frequency detected by the ion detection unit 6.

Thus, the control unit 16 changes the frequency of the pulse voltage output to the electrode 3b of the ionization unit 3. Thereby, the mass spectrometer can appropriately detect various types of samples such as drugs, explosives, and chemical substances.

In the above description, the pulse voltage frequency is switched between 10 kHz, 20 kHz, and 5 kHz. However, the present invention is not limited to this, and other frequencies may be used.

[Third Embodiment]
In 3rd Embodiment, the waveform of the pulse voltage output to the electrode 3b of the ionization part 3 is changed. In the following, parts different from the first and second embodiments will be described, and the same parts as the first and second embodiments will be described using the reference numerals of the first and second embodiments. .

FIG. 10 is a diagram showing a circuit example of the barrier power supply according to the third embodiment. 10, the same components as those in FIG. 7 are denoted by the same reference numerals. Below, a different part from FIG. 7 is demonstrated.

As shown in FIG. 10, the barrier power supply 8 has a variable capacitor VC1 whose capacitance can be varied. The capacity of the variable capacitor VC1 is varied by the control unit 16, for example.

The barrier power supply 8 can change the voltage waveform of the output pulse voltage according to the duty ratio of the clock input to the switching unit 32 and the capacity (resonance capacity) of the variable capacitor VC1. The control unit 16 can vary the duty ratio of the clock by changing “Ton” and “Toff” of the clock output to the barrier power supply 8.

FIG. 11 is a diagram for explaining the voltage waveform of the pulse voltage output from the barrier power supply. FIG. 11A shows an example of a single peak pulse waveform. FIG. 11B shows an example of a bimodal pulse waveform. FIG. 11C shows an example of a vibration pulse waveform.

11A, for example, in the circuit of FIG. 10, the frequency of the clock input to the drive unit 31 is “f” and the duty ratio of the clock input to the drive unit 31 is “D”. , And the capacitance of the variable capacitor VC1 is “C”, “f = 10 kHz”, “D = 55%”, and “C = 1000 pF”.

The bimodal pulse waveform shown in FIG. 11B is obtained by setting “f = 10 kHz”, “D = 75%”, and “C = 4700 pF” in the circuit of FIG. 10, for example.

The vibration pulse waveform shown in FIG. 11C is obtained by setting “f = 10 kHz”, “D = 90”, and “C = 1000 pF” in the circuit of FIG. 10, for example.

Note that the setting of “f”, “D”, and “C” is not limited to this, and the above three types of waveforms can be generated by other appropriate setting values.

FIG. 12 is a diagram showing an example of a timing chart of the mass spectrometer. In FIG. 12, a different part from FIG. 3 is demonstrated.

The barrier power supplies 8 and 9 vary the voltage waveform of the pulse voltage output to the switching unit 10 according to the duty ratio and resonance capacity output from the control unit 16. For example, the barrier power supplies 8 and 9 output three types of pulse voltages of “single peak pulse waveform”, “double peak pulse waveform”, and “vibration pulse waveform”.

A waveform W21 shown in FIG. 12 indicates a waveform of a positive pulse voltage output from the switching unit 10 to the electrode 3b. As shown in the waveform 21, the electrode 3b is supplied with pulse voltages having three types of voltage waveforms.

A waveform W22 shown in FIG. 12 indicates a waveform of a negative pulse voltage output from the switching unit 10 to the electrode 3b. As shown by the waveform 22, the electrode 3b is supplied with pulse voltages having three types of voltage waveforms.

In addition, the ion trap part 4b sweeps mass in each voltage waveform of a pulse voltage. Further, also in the measurement period 2, the control unit 16 outputs pulse voltages having a plurality of voltage waveforms in each barrier discharge. For example, in the example of FIG. 12, the control unit 16 outputs pulse voltages having three types of voltage waveforms even in each barrier discharge in the measurement period 2. Further, in the measurement period 2, the control unit 16 stores, for example, the ion amount of the voltage waveform having the highest ionization efficiency among the ion amounts obtained in each voltage waveform in the storage device.

FIG. 13 is a flowchart showing an operation example of the mass spectrometer. In FIG. 13, the same processes as those in FIG. In FIG. 13, processing different from that in FIG. 5 will be described.

In step S11, the control unit 16 outputs a positive pulse voltage to the electrode 3b of the ionization unit 3 (barrier discharge +), and outputs a negative voltage to the introduction unit 6b (ion introduction −). , 13 is controlled, and in step S11b, the barrier power supply 8 is controlled to output pulse voltages having different voltage waveforms. Thereby, for example, in the barrier discharge of the dotted frame D1 shown in FIG. 12, a pulse voltage having a different voltage waveform as shown in the waveform W21 is output to the electrode 3b.

The controller 16 also controls the barrier power supplies 8 and 9 so that pulse voltages having different voltage waveforms are output to the electrode 3b in steps S13b, 15b, and 17b as described above.

The control unit 16 controls the barrier power supplies 8 and 9 so that pulse voltages having different voltage waveforms are output to the electrode 3b in steps S22b and S26b. That is, the control unit 16 controls the barrier power supplies 8 and 9 so that pulse voltages having different voltage waveforms are output to the electrode 3b even during the measurement period T2.

The ion detector 6 detects ions at each mass (swept mass) in each voltage waveform in steps S23b and S27b. For example, the control unit 16 stores, in the storage device, the ion amount of the voltage waveform having the highest ionization efficiency among the ion amounts at each mass in each voltage waveform detected by the ion detection unit 6.

Thus, the control unit 16 changes the voltage waveform of the pulse voltage output to the electrode 3b of the ionization unit 3. Thereby, the mass spectrometer can appropriately detect various types of samples such as drugs, explosives, and chemical substances.

In addition, although the example which changes the frequency and voltage waveform of a pulse voltage was demonstrated in each of 2nd Embodiment and 3rd Embodiment, these can also be combined. For example, the control unit 16 may change the frequency to “10 kHz”, “20 kHz”, and “5 kHz” in each of the three voltage waveforms of the waveform W21 illustrated in FIG.

[Fourth Embodiment]
In the fourth embodiment, the voltage polarity of barrier discharge and ion introduction can be set by the user. In addition, the frequency and voltage waveform of the barrier discharge can be set by the user.

FIG. 14 is a diagram showing a screen example of the display device according to the fourth embodiment. As shown in FIG. 14, setting units 41 to 44 and a button 45 are displayed on the display device 26 of the mass spectrometer. The screen example shown in FIG. 14 is displayed on the display device 26, for example, when the mass spectrometer is turned on.

The display device 26 is provided with a touch panel on the screen, for example. The user can change the setting contents of the setting units 41 to 44 by tapping the touch panel on the screen. In addition, when the start button 45 is tapped, the control unit 16 performs mass spectrometry with the setting contents set in the setting units 41 to 44.

The setting unit 41 receives the setting of the voltage polarity of the barrier discharge from the user. For example, the user can set the voltage polarity of the barrier discharge by tapping the “+” or “−” portion displayed in the setting unit 41. More specifically, when the user taps the leftmost “+” portion shown in the setting unit 41, “+” and “−” are displayed, and the voltage polarity to be set is selected from among them. Can do. The leftmost “+” of the setting unit 41 sets, for example, the voltage polarity of the barrier discharge in the dotted frame D1 in FIG. 3, and the “−” next to the right indicates the voltage polarity of the barrier discharge in the dotted frame D2. “+” Next to the right side sets the voltage polarity of the barrier discharge in the dotted line frame D3, and “−” on the rightmost side sets the voltage polarity of the barrier discharge in the dotted line frame D4.

The setting unit 42 receives the setting of the voltage polarity for ion introduction from the user. For example, the user can set the voltage polarity for ion introduction by tapping the “+” or “−” portion displayed in the setting unit 42. More specifically, when the user taps the leftmost “−” portion shown in the setting unit 42, “+” and “−” are displayed, and the voltage polarity to be set is selected from among them. Can do. The leftmost “+” of the setting unit 42 sets, for example, the voltage polarity for ion introduction in the dotted frame D1 in FIG. 3, and the “−” next to the right indicates the voltage polarity for ion introduction in the dotted frame D2. The “+” next to the right sets the voltage polarity for ion introduction in the dotted line frame D3, and the “−” on the rightmost side sets the voltage polarity for ion introduction in the dotted line frame D4.

The setting unit 43 receives the frequency of the pulse voltage of the barrier discharge from the user. For example, the user can set the frequency of the pulse voltage of the barrier discharge by tapping the “10 kHz”, “20 kHz”, or “5 kHz” portion displayed in the setting unit 43. More specifically, when the user taps the “10 kHz” portion shown in the setting unit 43, “10 kHz”, “20 kHz”, and “5 kHz” are displayed, and the pulse voltage to be set is displayed from among them. The frequency can be selected. The leftmost “10 kHz” of the setting unit 43 sets the frequency of the pulse voltage on the left side of the waveforms W11 and W12 in FIG. 8, and the “20 kHz” on the right is the middle part of the waveforms W11 and W12. The frequency of the pulse voltage is set, and the rightmost “5 kHz” sets the frequency of the pulse voltage in the right part of the waveforms W11 and W12.

The setting unit 44 receives the voltage waveform of the barrier discharge pulse voltage from the user. For example, the user can set the voltage waveform of the pulse voltage of the barrier discharge by tapping the “single peak”, “double peak”, or “vibration” portion displayed in the setting unit 44. . More specifically, when the user taps the “single peak” portion shown in the setting unit 44, “single peak”, “double peak”, and “vibration” are displayed, and settings are made from among them. The voltage waveform of the pulse voltage can be selected. The leftmost “single peak” of the setting unit 44 sets the voltage waveform of the pulse voltage on the left side of the waveforms W21 and W22 in FIG. 12, and the “double peak” on the right side of the setting unit 44 indicates the waveforms W21 and W22. The voltage waveform of the pulse voltage in the middle part is set, and the rightmost “vibration” sets the voltage waveform of the pulse voltage in the right part of the waveforms W21 and W22.

When the user taps the button 45, the control unit 16 starts mass analysis and performs mass analysis with the setting contents set in the setting units 41 to 44. For example, the control unit 16 receives information input to the setting units 41 to 44 via the GUI 17.

Thus, by making it possible to switch the voltage polarity of the barrier discharge and ion introduction, the frequency of the pulse voltage of the barrier discharge, and the voltage waveform of the pulse voltage of the barrier discharge, the usability for the user is improved.

Note that all four sets of voltage polarity for barrier discharge and ion introduction need not be set. For example, when the target of the sample to be subjected to mass spectrometry is determined in advance, the user may set combinations other than the four voltage polarities. The same applies to the frequency and voltage waveform of the barrier discharge.

[Fifth Embodiment]
FIG. 15 is a diagram illustrating a block configuration example of a mass spectrometer according to the fifth embodiment. 15 that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

15 is omitted in the introduction unit 6b, the introduction power supplies 11 and 12, and the switching unit 13 from the mass spectrometer of FIG. 15 includes a CD power source 51 and a switching unit 52. In the mass spectrometer of FIG. 15, the function of the introduction part 6b shown in FIG. 1 is given to the CD 6ca of the detection part 6c.

The CD power supply 51 outputs a positive voltage of “+5 kV”, for example. The CD power supply 14 outputs a negative voltage of “−5 kV”, for example, as described in FIG.

The switching unit 52 outputs one of the voltages output from the CD power sources 14 and 51 to the CD 6 ca under the control of the control unit 16.

The general operation of the mass spectrometer shown in FIG. 15 will be described. The general operation of the mass spectrometer of FIG. 15 is the same as the general operation shown in the flowchart of FIG. 2, but the operation of step S6 is different. Below, step S6 from which a process differs is demonstrated.

The control unit 16 introduces the sample ions accumulated in the ion trap unit 4b into the detection unit 6c, and detects the mass of the ions (step S6). For example, the control unit 16 controls the switching unit 52 to output one voltage of the CD power sources 14 and 51 to the CD 6 ca, introduce the ions accumulated in the ion trap unit 4 b to the detection unit 6 c, and the mass of the ions. (Voltage polarity control will be described below). Thereby, the control part 16 can detect the drug etc. which are contained in the sample.

FIG. 16 is a diagram showing an example of a timing chart of the mass spectrometer. As shown by the one-dot chain line in FIG. 16, the mass spectrometer has two phases of a preamble period T1 and a measurement period T2. In the preamble period T1, the mass spectrometer determines which combination has the best ionization efficiency among the combinations of the voltage polarities of the barrier discharge and the ion introduction (electrode 3b and CD6ca). The mass spectrometer detects the mass of the sample in the measurement period T2 by a combination of the barrier discharge determined in the preamble period T1 and the voltage polarity of ion introduction.

The waveforms W1, W2, W3, W5, W7, and W8 shown in FIG. 16 are the same as the waveforms W1, W2, W3, W5, W7, and W8 in FIG. A waveform W4 in FIG. 16 indicates the timing of the voltage that the switching unit 52 outputs to the CD6ca. The switching unit 52 does not output the positive and negative voltages output from the CD power sources 14 and 51 to the CD 6ca when “OFF” shown in the waveform W4. The switching unit 52 outputs a negative voltage output from the CD power supply 14 to the CD6ca when “negative” shown in the waveform W4, and a positive output from the CD power supply 51 when “positive” shown in the waveform W4. The voltage is output to CD6ca. Note that “−5 kV” shown in the measurement period T2 of the waveform W4 indicates that the switching unit 52 outputs a negative voltage to the CD6ca, and is a specific value.

In the preamble period T1, the control unit 16 controls the switching unit 10 to switch the polarity of the pulse voltage output from the barrier power supplies 8 and 9 to the electrode 3b. In addition, the control unit 16 controls the switching unit 52 in the preamble period T1 to switch the polarity of the voltage output from the CD power sources 14 and 51 to the CD 6ca.

For example, as shown by dotted line frames D1 to D4 in FIG. 16, the control unit 16 sets the polarity of the voltage output from the barrier power sources 8 and 9 and the CD power sources 14 and 51 to positive, negative, and negative in the preamble period T1. Switching between four combinations of negative and positive, positive and positive, and negative and positive.

When all the combinations of the voltage polarities of the barrier power supplies 8 and 9 and the CD power supplies 14 and 51 are switched, the control unit 16 performs measurement following the preamble period T1 based on the detected amount of ions (ion intensity) in each switched polarity. In the period T2, the polarity of the voltage output to the electrode 3b and the CD6ca is determined.

For example, the control unit 16 integrates the ion intensity output from the ion detection unit 6 in each voltage polarity combination of the dotted line frames D1 to D4 shown in FIG. For example, in the combinations of the voltage polarities of the dotted line frames D1 to D4 shown in FIG. 16, the ion intensity as shown in FIG. 4 is obtained (the peak as shown in FIG. 4 does not appear depending on the combination of the voltage polarities). The control unit 16 integrates the ion intensity obtained in each of the dotted line frames D1 to D4. The control unit 16 determines whether or not the integrated value of each ion intensity in the dotted line frames D1 to D4 exceeds a predetermined threshold, and determines a combination of voltage polarities of the ion intensity exceeding the predetermined threshold. Then, the control unit 16 performs mass analysis of the sample in the measurement period T2 with the determined voltage polarity.

For example, it is assumed that the integrated ion intensity exceeds a predetermined threshold in the combination of voltage polarities in the dotted frame D1 shown in FIG. In this case, the control unit 16 sets the voltage polarity of the barrier discharge to “positive” (shown as “+3 kV” in FIG. 3) as shown by the dotted frames D5 and D6 in the measurement period T2 in FIG. The voltage polarity of the introduction is set to “negative” (shown as “−5 kV” in FIG. 3), and mass analysis of the sample is performed in the measurement period T2.

In this way, the control unit 16 of the mass spectrometer switches the polarity of the voltage supplied to the ionization unit 3 and the voltage supplied to the CD6ca (electron emission unit) in the preamble period T1, and detects ions in the switched polarity. Based on the quantity, in the measurement period T2 subsequent to the preamble period T1, the polarity of the voltage supplied to the ionization unit 3 and the voltage supplied to the CD6ca is controlled. Thereby, the control part 16 can determine the combination of voltage polarity with higher ionization efficiency, can perform mass analysis with the determined voltage polarity, and can obtain an appropriate mass spectrometry result.

[Sixth Embodiment]
FIG. 17 is a diagram illustrating a block configuration example of a mass spectrometer according to the sixth embodiment. The mass spectrometer shown in FIG. 17 is different from the system using the barrier discharge in the ion source of the mass spectrometer shown in FIG. 15 in that the ESI (Electrospray Ionization) is used. In FIG. 17, the same components as those in FIG. 15 are denoted by the same reference numerals, and the description thereof is omitted.

ESI is a method of ion source that ionizes while vaporizing a liquid sample. The mass spectrometer of FIG. 17 includes an ESI ion source 61 having a capillary 61a through which a liquid sample is passed, an introduction unit 62 that introduces a sample ionized by the ESI ion source 61 into the mass analysis unit 4, and an ESI power source 63. , 64, and a switching unit 65 that supplies the voltage output from the ESI power sources 63, 64 to the capillary 61 a in accordance with the control of the control unit 16.

The output voltages of the ESI power supplies 63 and 64 are switched by the switching unit 65 and applied to the capillary 61a. The ESI power supply 63 supplies, for example, a negative voltage of “−3 kV” to the capillary 61a, and the ESI power supply 64 supplies, for example, a positive voltage of “+3 kV” to the capillary 61a.

The timing chart of the mass spectrometer of FIG. 17 is the same as the timing chart of the mass spectrometer of FIG. 15 shown in FIG. However, in the mass spectrometer of FIG. 17, the waveform W <b> 3 of FIG. 16 indicates the timing of the voltage that the switching unit 65 outputs to the capillary 61 a of the ESI ion source 61.

The switching unit 65 does not output positive and negative voltages output from the ESI power sources 63 and 64 to the capillary 61a when “OFF” shown in the waveform W3. The switching unit 65 outputs a positive voltage output from the ESI power supply 64 to the capillary 61a when “positive” shown in the waveform W3. The switching unit 65 outputs a negative voltage output from the ESI power supply 63 to the capillary 61a when “negative” shown in the waveform W3. Note that “+3 kV” shown in the measurement period T2 of the waveform W3 indicates that the switching unit 65 outputs a positive voltage to the capillary 61a, and is a specific value.

In the waveform W3 of FIG. 16, the control unit 16 has four polarities of voltages output from the ESI power supplies 63 and 64 and the CD power supplies 14 and 51: positive and negative, negative and negative, positive and positive, and negative and positive. Switching in combination. However, it is known that in the system using ESI for the ion source, the voltage applied to the ion source and the generated ions often have the same polarity. Therefore, in the method using ESI for the ion source, when the waveform W3 voltage is positive, the waveform W4 voltage is set to negative polarity, and when the waveform W3 voltage is negative polarity, the waveform W4 voltage is set to positive polarity. May be set. That is, the control unit 16 may switch the polarity of the voltage output from the ESI power supplies 63 and 64 and the CD power supplies 14 and 51 between the positive and negative, and the negative and positive in the preamble period T1.

As described above, the control unit 16 of the mass spectrometer switches the polarity of the voltage supplied to the ionization unit of the ESI and the voltage supplied to the CD6ca in the preamble period T1, and based on the detected amount of ions in the switched polarity. In the measurement period T2 following the preamble period T1, the polarity of the voltage supplied to the ionization unit of the ESI and the voltage supplied to the CD6ca are controlled. Thereby, the control part 16 can determine the combination of voltage polarity with higher ionization efficiency, can perform mass analysis with the determined voltage polarity, and can obtain an appropriate mass spectrometry result.

In the above description, the method of switching the CD power sources 14 and 51 has been described. However, as shown in the first embodiment, the introduction unit 6b (for example, a mesh unit) is provided and the introduction power sources 11 and 12 are switched. Similar effects can be obtained.

[Seventh Embodiment]
FIG. 18 is a diagram illustrating a block configuration example of a mass spectrometer according to the seventh embodiment.
The mass spectrometer of FIG. 18 differs from the mass spectrometer of FIG. 15 in that the ion source is changed from a system using barrier discharge to a system using APCI (Atmospheric Pressure Chemical Ionization). In FIG. 18, the same components as those in FIG.

APCI is a method of an ion source that vaporizes a liquid sample and ionizes it by corona discharge. 18 includes a needle electrode 71, a counter electrode 72, a sample vaporization unit 73, an introduction unit 74 that introduces an ionized sample into the mass analysis unit 4, APCI power supplies 75 and 76, and a control unit. And a switching unit 77 that supplies the voltage output from the APCI power supplies 75 and 76 to the needle electrode 71 according to the control of 16.

The output voltages of the APCI power supplies 75 and 76 are switched by the switching unit 77 and applied to the needle electrode 71. A corona discharge region A11 is formed between the needle electrode 71 and the counter electrode 72, and the sample introduced from the sample vaporization unit 73 is ionized in this region. The APCI power source 75 supplies, for example, a negative voltage of “−3 kV” to the needle electrode 71, and the APCI power source 76 supplies, for example, a positive voltage of “+3 kV” to the needle electrode 71.

The timing chart of the mass spectrometer of FIG. 18 is the same as the timing chart of the mass spectrometer of FIG. 15 shown in FIG. However, in the mass spectrometer of FIG. 18, the waveform W <b> 3 of FIG. 16 indicates the timing of the voltage that the switching unit 77 outputs to the needle electrode 71.

The switching unit 77 does not output the positive and negative voltages output from the APCI power supplies 75 and 76 to the needle electrode 71 when “OFF” shown in the waveform W3. The switching unit 77 outputs a positive voltage output from the APCI power supply 76 to the needle electrode 71 when “positive” shown in the waveform W3. The switching unit 77 outputs a negative voltage output from the APCI power supply 75 to the needle electrode 71 when “negative” shown in the waveform W3. Note that “+3 kV” shown in the measurement period T2 of the waveform W3 indicates that the switching unit 77 outputs a positive voltage to the needle electrode 71, and is a specific value.

In the waveform W3 of FIG. 16, the control unit 16 has four polarities of the voltages output from the APCI power supplies 75 and 76 and the CD power supplies 14 and 51: positive and negative, negative and negative, positive and positive, and negative and positive. Switching in combination. However, it is known that in the method using APCI for the ion source, the voltage applied to the ion source and the generated ions often have the same polarity. Therefore, in the method using APCI for the ion source, when the waveform W3 voltage is positive, the waveform W4 voltage is set to negative polarity, and when the waveform W3 voltage is negative polarity, the waveform W4 voltage is set to positive polarity. May be set. That is, the control unit 16 may switch the polarity of the voltage output from the APCI power supplies 75 and 76 and the CD power supplies 14 and 51 in the preamble period T1 between two combinations of positive and negative and negative and positive.

As described above, the control unit 16 of the mass spectrometer switches the polarity of the voltage supplied to the ionization unit of the APCI and the voltage supplied to the CD6ca in the preamble period T1, and based on the detected amount of ions in the switched polarity. In the measurement period T2 subsequent to the preamble period T1, the polarity of the voltage supplied to the ionization unit of the APCI and the voltage supplied to the CD6ca are controlled. Thereby, the control part 16 can determine the combination of voltage polarity with higher ionization efficiency, can perform mass analysis with the determined voltage polarity, and can obtain an appropriate mass spectrometry result.

In the above description, the method of switching the CD power sources 14 and 51 has been described. However, as shown in the first embodiment, the introduction unit 6b (for example, a mesh unit) is provided and the introduction power sources 11 and 12 are switched. Similar effects can be obtained.

As mentioned above, although this invention was demonstrated using embodiment, the structure of a mass spectrometer is classified according to the main processing content in order to make an understanding of the structure of a mass spectrometer easy. The present invention is not limited by the way of classification and names of the constituent elements. The configuration of the mass spectrometer can be classified into more components depending on the processing content. Moreover, it can also classify | categorize so that one component may perform more processes. Further, the processing of each component may be executed by one hardware or may be executed by a plurality of hardware.

In addition, each processing unit in the above-described flowchart is divided according to the main processing contents in order to make the processing of the mass spectrometer easy to understand. The present invention is not limited by the way of dividing the processing unit or the name. The processing of the mass spectrometer can be divided into more processing units depending on the processing content. Moreover, it can also divide | segment so that one process unit may contain many processes.

Further, the technical scope of the present invention is not limited to the scope described in the above embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiment. The present invention can also be provided as a mass spectrometry method using a mass spectrometer.

1: capillary, 2: valve, 3: ionization unit, 3a: dielectric container, 3b: electrode, 4: mass analysis unit, 4a: chamber, 4b: ion trap unit, 4c: incap electrode, 4d: end cap electrode 5: Vacuum pump, 6: Ion detection section, 6a: Chamber, 6b: Introduction section, 6c: Detection section, 6ca: CD, 6cb: Scintillator, 6cc: Photomultiplier tube, 7: Pressure detection section, 8, 9: Barrier power source, 10: switching unit, 11, 12: introduction power source, 13: switching unit, 14: CD power source, 15: scintillator power source, 16: control unit, 17: GUI, T1: preamble period, T2: measurement period, 31 : Driving unit, 32: switching unit, 33: high voltage module, C1: capacitor, VC1: variable capacitor, 51: CD power supply, 52: switching unit, 61: ES Ion source, 61a: capillary, 62: introduction part, 63, 64: ESI power supply, 65: switching part, 71: needle electrode, 72: counter electrode, 73: sample vaporization part, 74: introduction part, 75, 76: APCI Power source, 77: switching unit.

Claims (11)

1. A first power source;
   An ionization unit that ionizes a sample by a voltage supplied from the first power source;
   An ion trap section for capturing ions of the sample ionized by the ionization section;
   A detection unit for detecting ions;
   A second power source;
   An introduction unit that introduces ions captured by the ion trap unit into the detection unit by a voltage supplied from the second power source;
   In the first period, the polarity of the voltage supplied to the ionization unit and the voltage supplied to the introduction unit is switched, and the second following the first period is based on the detected amount of ions in the switched polarity. In a period, a control unit for controlling the polarity of the voltage supplied to the ionization unit and the voltage supplied to the introduction unit;
   A mass spectrometer characterized by comprising:
2. The mass spectrometer according to claim 1,
   In the first period, the control unit is configured to change a polarity of a voltage supplied from the first power source to the ionization unit and a voltage supplied from the second power source to the introduction unit. Switching between four combinations of negative and positive, positive and positive, negative and positive,
   A mass spectrometer characterized by that.
3. The mass spectrometer according to claim 1,
   The control unit receives from the input device the voltage supplied to the ionization unit and the polarity of the voltage supplied to the introduction unit,
   A mass spectrometer characterized by that.
4. The mass spectrometer according to claim 1,
   The control unit changes a frequency of a voltage supplied to the ionization unit in the first period and the second period.
   A mass spectrometer characterized by that.
5. The mass spectrometer according to claim 4,
   The control unit receives a frequency of a voltage supplied to the ionization unit from an input device;
   A mass spectrometer characterized by that.
6. The mass spectrometer according to claim 1,
   The control unit changes a voltage waveform of a voltage supplied to the ionization unit in the first period and the second period.
   A mass spectrometer characterized by that.
7. The mass spectrometer according to claim 6,
   The control unit receives a voltage waveform of a voltage supplied to the ionization unit from an input device;
   A mass spectrometer characterized by that.
8. The mass spectrometer according to claim 1,
   The ionization unit ionizes the sample by barrier discharge.
   A mass spectrometer characterized by that.
9. The mass spectrometer according to claim 1,
   In the first period, the control unit is configured to change a polarity of a voltage supplied from the first power source to the ionization unit and a voltage supplied from the second power source to the introduction unit. And switching with two positive combinations,
   A mass spectrometer characterized by that.
10. A first power source;
    An ionization unit that ionizes a sample by a voltage supplied from the first power source;
    An ion trap section for capturing ions of the sample ionized by the ionization section;
    A detection unit for detecting ions;
    A second power source;
    An introduction unit that introduces ions captured by the ion trap unit into the detection unit by a voltage supplied from the second power source;
    A mass spectrometry method for a mass spectrometer having
    The control unit switches the polarity of the voltage supplied to the ionization unit and the voltage supplied to the introduction unit in the first period, and in the first period based on the detected amount of ions in the switched polarity. In the subsequent second period, the polarity of the voltage supplied to the ionization unit and the voltage supplied to the introduction unit is controlled.
    A mass spectrometric method characterized by the above.
11. A first power source;
    An ionization unit that ionizes a sample by a voltage supplied from the first power source;
    An ion trap section for capturing ions of the sample ionized by the ionization section;
    A second power source;
    An electron emitter that is supplied with a voltage supplied from the second power source and emits secondary electrons according to the amount of ions of ions captured by the ion trap;
    In the first period, the polarity of the voltage supplied to the ionization unit and the voltage supplied to the electron emission unit is switched, and the second following the first period is based on the detected amount of ions in the switched polarity. A control unit that controls the polarity of the voltage supplied to the ionization unit and the voltage supplied to the electron emission unit in the period of
    A mass spectrometer characterized by comprising:

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