Mass spectrometry device, voltage generation circuit, and control method for mass spectrometry device

Abstract

A mass spectrometry device (10) includes an ion generation mechanism, an ion trap mechanism (140), a detector (150), and a voltage generation circuit (180). The ion trap mechanism traps ions in an internal space surrounded by a plurality of electrodes. The detector detects ions discharged from the ion trap mechanism. The plurality of electrodes include a first electrode (141) that generates an electric field for trapping ions and a second electrode (142, 144) that generates an electric field for discharging specific ions from the ion trap mechanism in a state where ions are trapped. The voltage generation circuit includes a voltage source (181, 182), switches (SW1, SW2), and resistance circuits (RC1, RC2). The voltage of the voltage source (182) is lower than the voltage of the voltage source (181). The switches (SW1, SW2) selectively supply the voltage from the voltage sources (181, 182) to the first electrode, respectively. The resistance circuits (RC1, RC2) are connected to control terminals of the switches (SW1, SW2), respectively. The resistance values of the respective resistance circuits are variable.

Description

Technical Field

[0001] This disclosure relates to a mass spectrometry analysis apparatus, a voltage generation circuit for the mass spectrometry analysis apparatus, and a control method for the mass spectrometry analysis apparatus. Background Technology

[0002] Ion trap type mass spectrometry apparatuses utilizing digital ion traps are known, as disclosed in U.S. Patent No. 6900433 (Patent Document 1) and Japanese Patent Application Publication No. 2022-52108 (Patent Document 2). In such ion trap type mass spectrometry apparatuses, a rectangular high-voltage wave having a predetermined frequency corresponding to the mass range of the ions to be captured is applied as a capture high voltage to a ring electrode, thereby capturing the ions to be analyzed within the electric field generated by the ring electrode. Then, for example, a rectangular low-voltage wave is applied to an end cap electrode, obtained by dividing the rectangular high-voltage wave applied to the ring electrode according to a predetermined frequency division ratio, and the frequencies of the rectangular high-voltage wave and the rectangular low-voltage wave are scanned simultaneously. Through this operation, the captured ions are resonantly excited sequentially according to their mass-to-charge ratio (hereinafter also referred to as "m / z") and emitted from the ion emission port, and the emitted ions are detected by a detector. A mass spectrum can be obtained based on the detected ion intensity.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: US Patent No. 6900433

[0006] Patent Document 2: Japanese Patent Application Publication No. 2022-52108 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] In ion trap type mass spectrometry apparatuses as described above, the rectangular wave voltage applied to the electrodes of the ion trap mechanism is predicated on an ideal rectangular wave configuration. However, in the power supply circuit that generates the applied voltage, due to variations in the characteristics of each individual electronic component (machine difference), unavoidable finite rise time, and / or the effects of aging over time, the applied voltage may actually deviate from the ideal rectangular wave. Therefore, a mass spectrum obtained using such an applied voltage may differ from the mass spectrum obtained using an ideal waveform.

[0009] Typically, a mass calibration curve (function) is used to calibrate the obtained mass spectrometer. This mass calibration curve is obtained beforehand by measuring a standard sample consisting of specific known samples with the device. For example, the mass calibration curve is approximated by a straight line in a way that makes the measured values ​​of two specific samples in the standard sample consistent with the theoretical values.

[0010] However, as mentioned above, if the waveform of the applied voltage in the power supply circuit deviates from the ideal waveform, the mass calibration curve obtained based on the standard sample may itself be inaccurate. Therefore, the error in the mass measured with respect to the sample being analyzed will increase, potentially leading to a decrease in measurement accuracy.

[0011] This disclosure was made to solve this problem and aims to improve the measurement accuracy in ion trap type mass spectrometry analyzers.

[0012] Solution for solving the problem

[0013] The mass spectrometry apparatus disclosed herein relates to an ion trap type mass spectrometry apparatus. The mass spectrometry apparatus includes an ion generation mechanism, an ion trap mechanism, a detector, a voltage generation circuit, and a control device for controlling the voltage generation circuit. The ion generation mechanism supplies ions in a pulsed manner. The ion trap mechanism comprises multiple electrodes configured to trap ions in an internal space formed by an electric field within the internal space surrounded by the multiple electrodes. The detector detects ions discharged from the ion trap mechanism. The voltage generation circuit applies a voltage to the multiple electrodes. The multiple electrodes include a first electrode and a second electrode, and a high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generation circuit includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies voltage from the first voltage source to the first electrode. The second switch selectively supplies voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch, and the first resistor circuit is configured to have a variable resistance value. The second resistor circuit is connected to the control terminal of the second switch, and the second resistor circuit is configured to have a variable resistance value.

[0014] Another aspect of this disclosure relates to a voltage generation circuit used in an ion trap type mass spectrometry apparatus. The mass spectrometry apparatus includes an ion generation mechanism that supplies ions in a pulsed manner, an ion trap mechanism, and a detector. The ion trap mechanism comprises multiple electrodes configured to trap ions in an internal space formed by an electric field within the internal space surrounded by the multiple electrodes. The detector detects ions discharged from the ion trap mechanism. The multiple electrodes include a first electrode and a second electrode. A high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The apparatus includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies voltage from the first voltage source to the first electrode. The second switch selectively supplies voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch and is configured to have a variable resistance value. The second resistor circuit is connected to a control terminal of the second switch and is also configured to have a variable resistance value.

[0015] Another aspect of this disclosure relates to a method for controlling an ion trap-type mass spectrometry apparatus. The mass spectrometer includes an ion trap mechanism and a voltage generation circuit. The ion trap mechanism comprises a plurality of electrodes configured to trap ions in an internal space formed by an electric field within the internal space surrounded by the plurality of electrodes. The voltage generation circuit applies a voltage to the plurality of electrodes. The plurality of electrodes includes a first electrode and a second electrode, and a high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generation circuit includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies voltage from the first voltage source to the first electrode. The second switch selectively supplies voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch. The second resistor circuit is connected to a control terminal of the second switch. The method includes the following steps: i) using a standard sample to measure the mass accuracy; ii) determining whether the measured mass accuracy of the standard sample is within the reference range; and iii) if the mass accuracy of the standard sample is not within the reference range, adjusting the resistance value of at least one of the first resistor circuit and the second resistor circuit to bring the mass accuracy within the reference range.

[0016] Invention Effects

[0017] In the mass spectrometry analysis apparatus disclosed herein, a resistor circuit is provided on each control terminal of the two switches included in the voltage generation circuit that supplies voltage to the first electrode (ring electrode) included in the ion trap mechanism, allowing the resistance value to be set to a variable value. With this structure, since the voltages supplied to the ring electrode from the two voltage sources can be adjusted separately, the voltage supplied to the ring electrode can be made close to an ideal rectangular wave voltage. This reduces deviations in the mass calibration curve that may occur due to mechanical differences in the electronic components constituting the voltage generation circuit, such as the switches. Therefore, measurement accuracy can be improved in ion trap type mass spectrometry analysis apparatuses. Attached Figure Description

[0018] Figure 1 This is an overall block diagram of a mass spectrometry analysis device equipped with the voltage generation circuit described in Embodiment 1.

[0019] Figure 2 It is used for explanation Figure 1 A diagram showing the structure of the voltage generation circuit.

[0020] Figure 3 This is a graph used to illustrate the changes in the calibration curves of a standard sample when the gate voltages of each switch are changed.

[0021] Figure 4 This is a flowchart illustrating the correction method for the resistor circuit within a voltage generation circuit.

[0022] Figure 5 This is a diagram illustrating the structure of the voltage generation circuit involved in Embodiment 2.

[0023] Figure 6 It is shown Figure 5 The diagram shows the circuit diagrams for each resistor.

[0024] Figure 7 This is a diagram showing the resistor circuit of Modified Example 1.

[0025] Figure 8 This is a diagram showing the resistor circuit of variant example 2.

[0026] Figure 9 This is a diagram illustrating the structure of the voltage generation circuit involved in Embodiment 3.

[0027] Figure 10 This is a diagram used to illustrate the structure of the voltage generation circuit in Modified Example 3.

[0028] Figure 11 This is a diagram illustrating the ion trap mechanism of the mass spectrometry analysis apparatus according to Embodiment 4. Detailed Implementation

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals, and their descriptions will not be repeated.

[0030] [Implementation Method 1]

[0031] (Structure of a mass spectrometry analysis device)

[0032] Figure 1 This is an overall block diagram of the mass spectrometry analysis apparatus 10 equipped with the voltage generation circuit 180 according to Embodiment 1. The mass spectrometry analysis apparatus 10 is a matrix-assisted laser desorption / ionization digital ion trap mass spectrometer (MALDI-DITMS) as an example of an ion trap type mass spectrometry analysis apparatus.

[0033] Reference Figure 1 The mass spectrometry analysis device 10 includes a measurement unit 100, a vacuum pump 160, a laser irradiation unit 170, a voltage generation circuit 180, a gas supply unit 185, a control device 200, an operation unit 190, and a display unit 195.

[0034] The measuring unit 100 has a box-shaped chamber 105, which is configured to be evacuated by a vacuum pump 160. Inside the chamber 105, a sample stage 110, an extraction electrode 120, a quadrupole deflector 130, an ion trap mechanism 140, and a detector 150 are arranged.

[0035] A drive device (not shown) is installed on the sample stage 110. This drive device allows the sample stage 110 to move along the XY plane along the main surface of the sample stage 110. A sample plate 115 is placed on the sample stage 110. A sample SP, which is the object of analysis and is modulated by a mixed matrix, is placed on the sample plate 115, and a laser from the laser irradiation unit 170 (described later) is irradiated onto the sample SP. The laser enters the chamber 105 through a window 107 on the upper surface of the chamber 105, irradiating the sample SP approximately perpendicularly to the positive direction of the Z-axis in the figure. As a result, the sample components in the sample SP are vaporized and ionized. In the case of a MALDI digital ion trap mass spectrometer, positively charged ions (positive ions) and / or negatively charged ions (negative ions) are generated depending on the type of matrix, additives, etc., used. There are two operating modes: one that analyzes positive ions in the generated ions (positive ion mode) and the other that analyzes negative ions in the generated ions (negative mode). However, the following explanation will use the positive ion mode as an example.

[0036] The generated ions are drawn out from the vicinity of the sample plate 115 in the positive Z-axis direction by the electric field created by the potential difference between the sample stage 110 and the extraction electrode 120, and guided to the deflector 130. For example, a voltage of +10V is applied to the sample stage 110, and a voltage of -6kV is applied to the extraction electrode 120. The deflector 130 includes four cylindrical electrodes extending in the Y-axis direction. Viewed from the Y-axis direction, the four electrodes are respectively arranged at the four corners of a roughly square. In the deflector 130, a voltage is applied to each electrode, such that a deflection electric field is generated by the four electrodes. For example, a voltage of -6kV is applied to each electrode of the deflector 130. By this deflection electric field, the trajectory of the ions passing through the extraction electrode 120 is bent in the X-axis direction. The deflected ions are then guided into the interior of the ion trap mechanism 140.

[0037] The ion trap mechanism 140 includes an annular electrode 141 with an inner surface having a hyperboloid shape of rotation, and a pair of endcap electrodes 142 and 144 disposed opposite to the annular electrode 141. The inner surfaces of the endcap electrodes 142 and 144 each have a hyperboloid shape of rotation. By applying a predetermined voltage from the voltage generating circuit 180 to the annular electrode 141 and the endcap electrodes 142 and 144, ions can be captured in or discharged from the internal space 146 surrounded by these electrodes.

[0038] An entrance hole 143 is formed at the center of the end cap electrode 142, through which ions deflected by the deflector 130 enter the internal space 146. To introduce positive ions into the internal space 146, a voltage of -10V is applied to the end cap electrode 143 on the entrance side, and a voltage of +10V is applied to the end cap electrode 144 on the exit side. After the ions generated by laser irradiation of the sample reach the internal space 146 of the ion trap, i.e., after a predetermined time has elapsed since the laser irradiation, the end cap electrode 142 is set to a ground potential or a predetermined bias voltage, and a rectangular wave high voltage is applied to the ring electrode 141 from the voltage generation circuit 180, thereby forming a trapping electric field (pseudopotential) in the internal space 146 for trapping ions. This trapping electric field traps the ions introduced into the internal space 146.

[0039] For the captured ions, by adjusting the frequency and / or duty cycle of the rectangular wave voltage applied to the annular electrode 141, ions with a specific range of mass-to-charge ratios are selected as precursor ions, while ions with mass-to-charge ratios outside this range are discharged from the exit hole 145. Furthermore, in addition to the annular electrode 141, ions with a specific range of mass-to-charge ratios can also be selected as precursor ions by applying a predetermined voltage to the end cap electrode 142. In the case of MS analysis, with ions generated by laser irradiation of the sample trapped in the ion trap, a rectangular wave high voltage is applied to the annular electrode 141, while a rectangular wave low voltage (obtained by dividing the rectangular wave high voltage applied to the annular electrode 141 by a predetermined frequency division ratio) is applied to the end cap electrodes 142 and 144. Simultaneously, the frequencies of the rectangular wave high voltage and the rectangular wave low voltage are scanned, thereby causing ions to be discharged from the exit hole 145 in order of mass-to-charge ratio.

[0040] For precursor ions selected within the internal space 146, MS / MS analysis by collision-induced dissociation (CID) is performed as follows: First, with precursor ions selected and captured in the internal space 146, an inert gas, such as argon (Ar), is introduced into the internal space 146 as a collision gas from the gas supply unit 185. Then, an excitation voltage with a frequency equal to the secular frequency determined by the mass-to-charge ratio of the precursor ions is applied to the end cap electrodes 142 and 144. As a result, the precursor ions are dissociated due to vibration and collision with the collision gas, generating various product ions. Subsequently, by simultaneously scanning the frequencies of the rectangular high-voltage and rectangular low-voltage applied to the annular electrode 141 and the end cap electrodes 142 and 144, the generated product ions are discharged from the exit hole 145 in order of mass-to-charge ratio.

[0041] The detector 150 detects ions discharged from the ion trap mechanism 140 and outputs a detection signal corresponding to the amount of ions detected to the control device 200.

[0042] The laser irradiation unit 170 is controlled by the control device 200 to irradiate the sample SP in the chamber 105 with pulsed laser light, causing the sample components in the sample SP to ionize.

[0043] The voltage generating circuit 180, controlled by the control device 200, generates voltages to be applied to the annular electrode 141 and end cap electrodes 142 and 144 included in the ion trap mechanism 140. During each stage of the analysis, the voltage generating circuit 180 adjusts the voltages applied to the annular electrode 141 and end cap electrodes 142 and 144 to perform ion trapping within the ion trap mechanism 140, selection of precursor ions, generation of product ions, and removal of ions in mass-to-charge ratio order.

[0044] The gas supply unit 185 includes a storage unit for storing inert gases such as helium (He), nitrogen (N2), or argon (Ar), and a flow regulating unit for adjusting the flow rate of these gases. The gas supply unit 185 cools the ions in the internal space 146 of the ion trap mechanism 140 by supplying appropriate gas to the internal space 146, and causes the precursor ions to dissociate to generate product ions.

[0045] The control device 200, such as a general-purpose personal computer (PC) or server device, provides overall control of the mass spectrometry analysis device 10 and processes the detection signals of ions detected by the detector 150 to generate a mass spectrum. The control device 200 includes a CPU (Central Processing Unit) 210, a memory 220, and an interface (I / F) 230. The CPU 210, memory 220, and interface 230 are configured to be interconnected via a common communication bus 240, enabling them to exchange information.

[0046] CPU 210 is configured to execute the predetermined arithmetic operations described in the program. Memory 220 includes ROM (Read-Only Memory) and RAM (Random Access Memory). ROM stores the program executed by CPU 210. RAM temporarily stores data generated by the program executed by CPU 210, as well as data input via interface 230. RAM also functions as temporary data storage for use as a working area. Additionally, memory 220 may also include high-capacity storage devices such as HDD (Hard Disc Drive), optical drives, and SSD (Solid State Drive).

[0047] Interface 230 facilitates signal exchange between control device 200 and external devices. Interface 230 may include a wireless communication unit (not shown) for transmitting and receiving signals wirelessly.

[0048] The control device 200 is connected to the operation unit 190 and the display unit 195. The operation unit 190 includes, for example, a keyboard, mouse, or touch panel, and is configured to allow user input of settings. The display unit 195 is configured to include, for example, a liquid crystal display (LCD) panel or an organic EL (Electro-Luminescence) panel, displaying device settings, operation information, and analysis results such as mass spectrometry to the user. Additionally, the display unit 195 may include a printing device such as a printer.

[0049] The above description shows an example of the applied voltage for each part in positive ion mode. However, in negative ion mode, for example, the following voltages are applied to each part to introduce negative ions generated from the sample into the internal space: a voltage of -10V is applied to the sample stage 110, and a voltage of +6kV is applied to the deflector 130. Furthermore, when ions are introduced into the ion trap, a voltage of +10V is applied to the end cap electrode 143 on the inlet side, and a voltage of -10V is applied to the end cap electrode 144 on the outlet side. Moreover, when ion capture, precursor ion selection, and ion discharge are performed, voltages with opposite polarities to those in positive ion mode are applied as a rectangular high-voltage applied to the ring electrode 141 and a rectangular low-voltage applied to the end cap electrode 142.

[0050] (Structure of voltage generation circuit)

[0051] Next, use Figure 2 This section describes the details of the voltage generation circuit 180 used to generate a rectangular wave high voltage. Figure 2 It is used for explanation Figure 1 A more detailed structural diagram of the voltage generation circuit 180 is shown. The voltage generation circuit 180 includes input terminals T1 and T2, output terminal T3, high-voltage side power supply 181, low-voltage side power supply 182, and switching circuit 183. Additionally, the switching circuit 183 includes resistor circuits RC1 and RC2, switches SW1 and SW2, and buffers BF1 and BF2.

[0052] Switches SW1 and SW2 are semiconductor switches such as metal-oxide-semiconductor field-effect transistors (MOSFETs) or insulated-gate bipolar transistors (IGBTs). In the following description, N-channel MOSFETs will be used as an example to illustrate switches SW1 and SW2.

[0053] The drain electrode of switch SW1 is connected to the high-voltage side power supply 181, and the source electrode is connected to the drain electrode of switch SW2. The source electrode of switch SW2 is connected to the low-voltage side power supply 182. The connection node ND1 between the source electrode of switch SW1 and the drain electrode of switch SW2 is connected to the output terminal T3. The output terminal T3 is connected to the ring electrode 141 of the ion trap mechanism 140.

[0054] The high-voltage side power supply 181 is a voltage source capable of supplying a predetermined positive DC voltage V1. Conversely, the low-voltage side power supply 182 is a voltage source capable of supplying a predetermined DC voltage V2 that is lower than the high-voltage side power supply 181 (V1 > V2). The DC voltage V2 can be any voltage lower than the DC voltage V1, and can be either positive or negative. For example, the DC voltage V2 can be set to V2 = -V1, which has the opposite polarity to the DC voltage V1 and the same absolute value.

[0055] As described below, switches SW1 and SW2 operate complementaryly to each other. Therefore, when switch SW1 is on, i.e., switch SW2 is off, the DC voltage V1 from the high-voltage side power supply 181 is supplied to the ring electrode 141 via output terminal T3. Conversely, when switch SW1 is off, i.e., switch SW2 is on, the DC voltage V2 from the low-voltage side power supply 182 is supplied to the ring electrode 141 via output terminal T3.

[0056] The gate terminal of switch SW1, serving as the control terminal, is connected to one end of resistor circuit RC1. The other end of resistor circuit RC1 is connected to input terminal T1 via buffer BF1. Similarly, the gate terminal of switch SW2, serving as the control terminal, is connected to one end of resistor circuit RC2. The other end of resistor circuit RC2 is connected to input terminal T2 via buffer BF2. Each resistor in resistor circuits RC1 and RC2 is, for example, a semi-adjustable resistor, configured to allow for manual variable setting of its resistance value. Buffers BF1 and BF2 are, for example, amplifiers with a gain of 1, used for noise removal and impedance adjustment in the input signal.

[0057] Control signals Pcon and Ncon are supplied from control device 200 to input terminals T1 and T2, respectively. Control signals Pcon and Ncon are rectangular wave signals with inverted phases. That is, when control signal Pcon is Hi (high), control signal Ncon becomes Lo (low), and when control signal Pcon is Lo, control signal Ncon becomes Hi. The duty cycle and frequency of control signals Pcon and Ncon are controlled by control device 200.

[0058] By supplying control signals Pcon and Ncon from the control device 200 to the voltage generation circuit 180 of this structure, a rectangular wave voltage Vout with voltage V1 as the maximum voltage and voltage V2 as the minimum voltage is supplied to the ring electrode 141.

[0059] In ion trap type mass spectrometry analyzers like those described above, the gate resistance of the switch in the voltage generation circuit is typically set to a predetermined fixed resistance at the time of manufacture. However, the inventors have discovered that due to mechanical differences in the characteristics of the switches used, unavoidable finite rise times, deviations in the resistance values ​​of the wiring connections, and / or changes in characteristics due to aging, the rectangular wave voltage applied to the electrodes of the ion trap mechanism deviates from the ideal rectangular waveform. If mass spectra are obtained using such rectangular wave voltages, the resulting mass spectra will differ from those of the ideal rectangular wave voltage, potentially affecting the analytical results.

[0060] Typically, a mass calibration curve is used to calibrate the obtained mass spectrometer. This calibration curve is obtained by measuring a standard sample composed of specific known samples with the device beforehand. For example, the mass calibration curve is approximated by a straight line in a way that makes the measured values ​​of two specific samples in the standard sample consistent with the theoretical values. However, as mentioned above, if the waveform of the applied voltage in the power supply circuit deviates from the ideal waveform, the mass calibration curve obtained from the standard sample may itself be inaccurate. This will increase the error in the measured mass, potentially leading to a decrease in measurement accuracy.

[0061] Therefore, in the mass spectrometry analysis apparatus 10 of Embodiment 1, in the voltage generating circuit 180 for generating the voltage supplied to the electrodes of the ion trap mechanism 140, resistor circuits RC1 and RC2 with adjustable resistance values ​​are provided at the gate terminals of the switches SW1 and SW2 that generate the supply voltage to the ring electrode 141. By adjusting the resistance values ​​of these resistor circuits RC1 and RC2, deviations in the rectangular wave voltage caused by mechanical differences in the switches SW1 and SW2 can be reduced, and appropriate mass calibration curves corresponding to each device can be obtained. Therefore, in the ion trap type mass spectrometry analysis apparatus, measurement accuracy can be improved.

[0062] (Correction method for resistive circuits)

[0063] Figure 3 This is a graph illustrating the changes in the calibration curves of a standard sample when the resistance values ​​of resistors RC1 and RC2 are changed, thereby altering the gate voltages of each switch. Figure 3 In the various charts, the horizontal axis shows the mass-to-charge ratio (m / z), and the vertical axis shows the error between the mass obtained from the measured mass spectrum and the actual mass.

[0064] exist Figure 3 The example shows the mass calibration curve obtained by measuring the mass spectra of a standard sample consisting of 7 known samples, and setting the mass error of the sample with the smallest mass (m / z=1046.54) and the sample with the second largest mass (m / z=2465.20) to 0 [ppm].

[0065] Line LN11 in the middle section of Figure (B) is the quality calibration curve when the resistance values ​​R1 and R2 of resistor circuits RC1 and RC2 are set to α [Ω]. Line LN10 in the upper section of Figure (A) is the quality calibration curve when the resistance value of resistor circuit RC1 is reduced and set to β [Ω] from the state in Figure (B). Furthermore, line LN12 in the lower section (C) is the quality calibration curve when the resistance value of resistor circuit RC2 is reduced and set to β [Ω] from the state in Figure (B).

[0066] exist Figure 3 In the example, when (R1, R2) = (α, α) as shown in the middle section (B), the quality error is almost flat across the entire range. In the upper section (A), where (R1, R2) = (β, α) and the resistance value of resistor RC1 is smaller than that of resistor RC2, the quality error tends to convex downwards overall. On the other hand, in the lower section (C), where (R1, R2) = (α, β) and the resistance value of resistor RC2 is smaller than that of resistor RC1, the quality error tends to convex upwards overall.

[0067] Therefore, in Figure 3 In the example of the mass spectrometry analysis apparatus used, if the obtained mass calibration curve is convex downwards as in the upper section (A), it can be adjusted by increasing the resistance value of resistor circuit RC1 or decreasing the resistance value of resistor circuit RC2 to approximate a mass calibration curve like the middle section (B). Conversely, if the obtained mass calibration curve is convex upwards as in the lower section (C), it can be adjusted by increasing the resistance value of resistor circuit RC2 or decreasing the resistance value of resistor circuit RC1 to approximate a mass calibration curve like the middle section (B). Furthermore, Figure 3 Such a change in the quality calibration curve is one example; in other voltage generation circuits, the quality calibration curve sometimes exhibits different characteristics when the resistance value is changed.

[0068] In this way, by pre-measuring the pattern of changes in the quality calibration curve when the resistance value of each resistor circuit changes in each device, the deviation of the quality calibration curve can be adjusted by correcting the resistance value of each resistor circuit during regular maintenance, etc.

[0069] Figure 4This is a flowchart illustrating the calibration method for the resistor circuits RC1 and RC2 within the voltage generation circuit 180. In step (hereinafter, step S.) 10, the adjuster measures the mass accuracy (mass error) using a standard sample. Then, in S20, the adjuster determines whether the obtained mass accuracy is within the reference range in the target m / z range. Here, the reference range is, for example, within ±100 [ppm].

[0070] If the obtained quality accuracy is within the reference range (YES in S20), the adjustment personnel skip the subsequent steps and end the adjustment work because no adjustment of the quality calibration curve is required. On the other hand, if the quality accuracy is outside the reference range (NO in S20), the quality calibration curve needs to be adjusted. Therefore, in S30, the adjustment personnel determine the correction amount of the resistance values ​​of resistor circuits RC1 and RC2 by comparing the obtained quality accuracy with the pre-measured measurement mode. Then, in S40, the adjustment personnel adjust resistor circuits RC1 and RC2 to achieve the determined resistance values.

[0071] Then, return to S10, where the personnel use the adjusted resistance value and measure the quality accuracy again using a standard sample. Repeat the operations from S10 to S40 until the quality accuracy reaches the desired reference range.

[0072] By adjusting the mass calibration curve in this way, the mass error of the mass calibration curve within the target m / z range can be reduced. Therefore, the influence of mechanical differences in electronic components in the voltage generation circuit can be reduced, improving the measurement accuracy of the mass spectrometry analyzer.

[0073] The "laser irradiation unit 170" in Embodiment 1 is an example of the "ion generation mechanism" in this disclosure. The "ring electrode 141" and "end cap electrodes 142, 144" in Embodiment 1 correspond to the "first electrode" and "second electrode" in this disclosure, respectively. The "high-voltage side power supply 181" and "low-voltage side power supply 182" in Embodiment 1 correspond to the "first voltage source" and "second voltage source" in this disclosure, respectively. The "switch SW1" and "switch SW2" in Embodiment 1 correspond to the "first switch" and "second switch" in this disclosure, respectively. The "resistor circuit RC1" and "resistor circuit RC2" in Embodiment 1 correspond to the "first resistor circuit" and "second resistor circuit" in this disclosure, respectively.

[0074] [Implementation Method 2]

[0075] In Embodiment 1, a structure is described that ensures quality accuracy by setting a semi-adjustable resistor configured in the gate resistor of the voltage generation circuit so that it can be adjusted by an adjustment personnel during factory shipment or maintenance.

[0076] However, in the structure of Embodiment 1, when adjusting the semi-adjustable resistor, the voltage generation circuit needs to be turned on, and the adjustment personnel need to directly operate the semi-adjustable resistor on the substrate. Therefore, the voltage generation circuit needs to be turned on every time an adjustment is made, which may increase the adjustment time.

[0077] Therefore, in Embodiment 2, a structure is described that reduces adjustment time by setting the resistor circuit in the voltage generation circuit to a structure that can be adjusted from outside the voltage generation circuit.

[0078] Figure 5 This is a diagram illustrating the structure of the voltage generating circuit 180A according to Embodiment 2. The voltage generating circuit 180A has the following structure: Figure 2 The switching circuit 183 in the voltage generation circuit 180 shown is replaced with a switching circuit 183A, and input terminals T4 and T5 are added. In the voltage generation circuit 180A, elements that are repeated in the voltage generation circuit 180 are not described again.

[0079] Reference Figure 5 In the switching circuit 183A of the voltage generation circuit 180A, the resistor circuits RC1 and RC2 of the voltage generation circuit 180 are replaced with resistor circuits RC1A and RC2A. Each resistor circuit in RC1A and RC2A is a variable resistor whose resistance value can be variably set according to a control signal from an external source. Input terminals T4 and T5 receive control signals SC1 and SC2 from the control device 200, respectively. Resistor circuit RC1A can switch its resistance value in multiple stages based on the control signal SC1 received at input terminal T4. Similarly, resistor circuit RC2A can also switch its resistance value in multiple stages based on the control signal SC2 received at input terminal T5.

[0080] Figure 6 It is shown Figure 5 Detailed circuit diagrams of each resistor circuit. Figure 6 The example provided illustrates the detailed circuit of resistor circuit RC1A, but the same circuit structure applies to resistor circuit RC2A.

[0081] The resistor circuit RC1A includes resistors R11, R12, and R13 connected in series between switch SW1 and buffer BF1, and a bypass circuit BP1. The bypass circuit BP1 includes switches TR1 and TR2, for example, constructed from MOSFETs. Switch TR1 is connected between connection node N1 between resistors R11 and R12 and connection node N3 between resistor R13 and buffer BF1. Additionally, switch TR2 is connected between connection node N2 between resistors R12 and R13 and connection node N3.

[0082] Switch TR1 is switched between on and off according to the gate signal GS1 in control signal SC1. Similarly, switch TR2 is switched between on and off according to the gate signal GS2 in control signal SC1. By turning on only switch TR1, resistors R12 and R13 are bypassed, and the control signal Pcon passes through resistor R11 only. By turning on only switch TR2, resistor R13 is bypassed, and the control signal Pcon passes through resistors R11 and R12. By turning off both switches TR1 and TR2, the control signal Pcon passes through resistors R11, R12, and R13.

[0083] Thus, by switching switches TR1 and TR2 according to control signal SC1, a portion of resistors R11, R12, and R13 can be selectively bypassed. Therefore, the gate resistance of switch SW1 can be switched in three stages based on a signal supplied externally to the voltage generation circuit 180A without needing to activate it. This reduces the adjustment time required by the operator during adjustment work.

[0084] Furthermore, regarding the control signal SC1, for example, it may be output from the control device 200 to the voltage generation circuit 180A based on input from the adjustment personnel to the operation unit 190. Alternatively, if an automatic calibration sequence function is provided, the control signal SC1 may be automatically output from the control device 200 to the voltage generation circuit 180A according to the calibration sequence.

[0085] In Embodiment 2, each switch in "Switch TR1" and "Switch TR2" corresponds to the "Switching Unit" in this disclosure. In Embodiment 2, "Resistor Circuit RC1A" and "Resistor Circuit RC2A" correspond to the "First Resistor Circuit" and "Second Resistor Circuit" in this disclosure, respectively.

[0086] (Variation Example 1)

[0087] In Modification 1, the structure of a resistor circuit that allows for multi-stage adjustment of the gate resistance by using a decoder to activate more switching units is explained. Furthermore, in Modification 1, for ease of explanation, the resistor circuit on the switch SW1 side is described as an example.

[0088] Figure 7 This is a diagram showing the resistor circuit RC1B of Modified Example 1. Similar to the resistor circuit RC1A of Embodiment 2, resistor circuit RC1B includes multiple resistors R11 to R19 connected in series between switch SW1 and buffer BF1, and a bypass circuit BP2. Bypass circuit BP2 includes switches TR1 to TR8 and decoder 184.

[0089] Switch TR1 is connected between connection node N1 between resistors R11 and R12 and connection node N9 between resistor R19 and buffer BF1. Switch TR2 is connected between connection node N2 between resistors R12 and R13 and connection node N9. Switch TR3 is connected between connection node N3 between resistors R13 and R14 and connection node N9. Switch TR4 is connected between connection node N4 between resistors R14 and R15 and connection node N9. Switch TR5 is connected between connection node N5 between resistors R15 and R16 and connection node N9. Switch TR6 is connected between connection node N6 between resistors R16 and R17 and connection node N9. Switch TR7 is connected between connection node N7 between resistors R17 and R18 and connection node N9. Switch TR8 is connected between connection node N8 between resistors R18 and R19 and connection node N9.

[0090] By switching the switches TR1 to TR8 on and off, resistors R11 to R19 can be selectively bypassed.

[0091] Decoder 184 is an integrated circuit configured to control switches TR1 to TR8 according to control signal SC1 input from control device 200. Control signal SC1 consists of 3 bits of signals B1 to B3. That is, decoder 184 can perform 8 different (2^35) operations based on the states of signals B1 to B3. 3 The decoder 184 has eight outputs, each connected to the gate terminal of a switch TR1 to TR8. The outputs of the decoder 184 allow any one of the switches TR1 to TR8 to be turned on.

[0092] When switch TR1 is on, resistors R12-R19 are bypassed, and the control signal Pcon passes through resistor R11. When switch TR2 is on, resistors R13-R19 are bypassed, and the control signal Pcon passes through resistors R11 and R12. When switch TR3 is on, resistors R14-R19 are bypassed, and the control signal Pcon passes through resistors R11-R13. When switch TR4 is on, resistors R15-R19 are bypassed, and the control signal Pcon passes through resistors R11-R14. When switch TR5 is on, resistors R16-R19 are bypassed, and the control signal Pcon passes through resistors R11-R15. When switch TR6 is on, resistors R16-R19 are bypassed, and the control signal Pcon passes through resistors R11-R15. When switch TR7 is on, resistors R18 and R19 are bypassed, and the control signal Pcon passes through resistors R11-R17. When switch TR8 is on, resistor R19 is bypassed, and control signal Pcon passes through resistors R11 to R18. When switches TR1 to TR8 are all off, control signal Pcon passes through all resistors R11 to R19.

[0093] Thus, by using the decoder 184, the gate resistance of switch SW1 can be switched in nine stages according to the 3-bit control signal SC1 from the control device 200. Therefore, the adjustment time of the adjustment personnel can be reduced during the adjustment operation.

[0094] Furthermore, a digital potentiometer can be used as the resistor circuit RC1B. A digital potentiometer is a variable resistor IC equipped with non-volatile memory, and its resistance value changes based on the control signal SC1 from the control device 200. For example, in one example of a potentiometer, 1kΩ can be set at 256 positions.

[0095] In Modification 1, each of the switches from "Switch TR1" to "Switch TR8" corresponds to the "Switching Unit" in this disclosure.

[0096] (Variation Example 2)

[0097] In Modification 2, a resistor circuit structure using a semi-adjustable resistor and an actuator for driving the semi-adjustable resistor is described. Furthermore, in Modification 2, for ease of explanation, a resistor circuit on the switch SW1 side is described as an example.

[0098] Figure 8This is a diagram showing the resistor circuit RC1C of Modified Example 2. The resistor circuit RC1C includes a resistor R20 as a semi-adjustable resistor and a motor M10. The motor M10 is, for example, a stepper motor, controlled by a control signal SC1 from the control device 200. The control signal SC1 is a pulse signal, and the rotation axis of the motor M10 rotates according to the number of pulses in the control signal SC1. The rotation axis of the motor M10 is connected to a trimmer TM1 of the resistor R20. Thus, by rotating the rotation axis of the motor M10, the gate resistance of the switch SW1 can be changed.

[0099] Thus, in the resistor circuit RC1C, the gate resistance of switch SW1 can be switched based on a signal supplied externally from the voltage generation circuit. Therefore, the adjustment time of the adjustment personnel can be reduced during the adjustment operation.

[0100] [Implementation Method 3]

[0101] As described above, in a digital ion trap mass spectrometer, by switching the polarity of the ion trap mechanism, measurements can be performed in two modes: a "positive ion mode" that analyzes positively charged ions and a "negative ion mode" that analyzes negatively charged ions.

[0102] However, the inventors discovered that the optimal mass calibration curve in "positive ion mode" is not necessarily optimal in "negative ion mode," and the appropriate mass calibration curves for each mode are different.

[0103] In Embodiment 3, a structure is described that allows setting a mass calibration curve suitable for each mode in a mass spectrometry analyzer capable of switching between "positive ion mode" and "negative ion mode".

[0104] Figure 9 This is a diagram illustrating the structure of the voltage generating circuit 180B according to Embodiment 3. In the voltage generating circuit 180B, the following structure is used: the switching circuit 183A in the voltage generating circuit 180A described in Embodiment 2 is replaced by the switching circuit 183B.

[0105] In the switching circuit 183B, in addition to switches SW1 and SW2 and buffers BF1 and BF2, it also includes resistor circuits RC1D and RC2D and relays RY1 and RY2. In addition, resistor circuit RC1D includes resistors R1P and R1N as semi-adjustable resistors, and resistor circuit RC2D includes resistors R2P and R2N as semi-adjustable resistors.

[0106] Each of the relays RY1 and RY2 has one input terminal and two output terminals (first terminal and second terminal), and each relay is configured to output a signal received at the input terminal to either the first terminal or the second terminal.

[0107] The input terminal of relay RY1 is connected to buffer BF1. The first terminal of relay RY1 is connected to the gate terminal of switch SW1 via resistor R1P. Additionally, the second terminal of relay RY1 is connected to the gate terminal of switch SW1 via resistor R1N. Relay RY1 is controlled by a control signal SC1 received at input terminal T4 from control device 200, and switches between the first path via resistor R1P and the second path via resistor R1N.

[0108] Similarly, the input terminal of relay RY2 is connected to buffer BF2. The first terminal of relay RY2 is connected to the gate terminal of switch SW2 via resistor R2P. Additionally, the second terminal of relay RY2 is connected to the gate terminal of switch SW2 via resistor R2N. Relay RY2 is controlled according to the control signal SC2 received at input terminal T5 from control device 200, and switches between the first path via resistor R2P and the second path via resistor R2N.

[0109] In embodiment 3, the polarity of the control signals supplied from the control device 200 to the input terminals T1 and T2 is switched in both the positive and negative modes. Specifically, in the positive mode, a control signal Pcon is supplied to input terminal T1, and a control signal Ncon is supplied to input terminal T2. Conversely, in the negative mode, a control signal Ncon is supplied to input terminal T1, and a control signal Pcon is supplied to input terminal T2.

[0110] In positive mode, relays RY1 and RY2 are switched to the first path according to control signals SC1 and SC2. That is, resistor R1P in resistor circuit RC1D and resistor R2P in resistor circuit RC2 are selected. On the other hand, in negative mode, relays RY1 and RY2 are switched to the second path according to control signals SC1 and SC2. That is, resistor R1N in resistor circuit RC1D and resistor R2N in resistor circuit RC2 are selected.

[0111] Then, by adjusting resistors R1P and R2P in a manner that becomes a quality calibration curve suitable for the positive mode, and adjusting resistors R1N and R2N in a manner that becomes a quality calibration curve suitable for the negative mode, quality accuracy can be ensured in each measurement mode.

[0112] Furthermore, in the switching circuit 183B of Embodiment 3, a structure is used where a relay switches a pre-adjusted semi-adjustable resistor according to the measurement mode; however, it can also be configured to use... Figures 6-8 The variable resistor shown has a structure that changes its resistance value according to the control signal from the control device based on the measurement mode.

[0113] In Embodiment 3, "resistor circuit RC1D" and "resistor circuit RC2D" correspond to "first resistor circuit" and "second resistor circuit" in this disclosure, respectively. In Embodiment 3, "resistor R1P", "resistor R1N", "resistor R2P" and "resistor R2N" correspond to "first resistor" to "fourth resistor" in this disclosure, respectively.

[0114] (Variation Example 3)

[0115] In Variation 3, a structure is described in which the polarity of the gate signal supplied to each switch is switched according to the measurement mode in the switching circuit.

[0116] Figure 10 This is a diagram illustrating the structure of the voltage generating circuit 180C in Modified Example 3. In the voltage generating circuit 180C, the following structure is adopted: the switching circuit 183B of Embodiment 3 is replaced by the switching circuit 183C, and the resistor circuits RC1D and RC2D are replaced by resistor circuits RC1E and RC2E, respectively.

[0117] Resistor circuit RC1E, like resistor circuit RC1D in Embodiment 3, includes resistors R1P and R1N, but the difference is that the connection destination of resistor R1N used in negative mode is changed to the gate terminal of switch SW2. Similarly, resistor circuit RC2E, like resistor circuit RC2D in Embodiment 3, includes resistors R2P and R2N, but the difference is that the connection destination of resistor R2N used in negative mode is changed to the gate terminal of switch SW1.

[0118] By configuring this connection structure, in positive mode, the control signal Pcon supplied from the control device 200 to the input terminal T1 is supplied to the gate terminal of switch SW1 via resistor R1P, and the control signal Ncon supplied to the input terminal T2 is supplied to the gate terminal of switch SW2 via resistor R2P. On the other hand, in negative mode, the control signal Pcon supplied to the input terminal T1 is supplied to the gate terminal of switch SW2 via resistor R1N, and the control signal Ncon supplied to the input terminal T2 is supplied to the gate terminal of switch SW1 via resistor R2N. That is, there is no need to switch the polarity of the control signals Pcon and Ncon supplied from the control device 200 to the input terminals T1 and T2 according to the measurement mode; the measurement mode can be switched simply by switching relays RY1 and RY2.

[0119] Then, by setting resistors R1P and R2P to resistance values ​​suitable for the positive mode and resistors R1N and R2N to resistance values ​​suitable for the negative mode, a quality calibration curve suitable for each measurement mode can be obtained when switching measurement modes. Therefore, quality accuracy can be ensured in each measurement mode.

[0120] Alternatively, it can be configured as follows: replacing the semi-adjustable resistor in the switching circuit 183C of Modified Example 3. Figures 6-8 The variable resistor shown is switched by a relay according to the measurement mode, and its resistance value is changed according to the control signal from the control device.

[0121] In Variation 3, “resistor circuit RC1E” and “resistor circuit RC2E” correspond to “first resistor circuit” and “second resistor circuit” in this disclosure, respectively.

[0122] [Implementation Method 4]

[0123] In Embodiment 1, an example was described in which the ion trap mechanism has a structure having an annular electrode and an end cap electrode with a hyperboloid shape of rotation, but the ion trap mechanism is not limited to this structure.

[0124] In Embodiment 4, an example is described of applying the features of this disclosure to a mass spectrometer that uses a quadrupole linear ion trap as an ion trap mechanism.

[0125] Figure 11This is a diagram illustrating the ion trap mechanism 340 of the mass spectrometry apparatus according to Embodiment 4. The ion trap mechanism 340 includes two pairs of opposing electrodes 341A, 341B and electrodes 342A, 342B. Each electrode has a cylindrical or semi-cylindrical shape. Electrode 341A is opposite to electrode 341B, and electrode 342A is opposite to electrode 342B. Electrodes 341A and 341B in the ion trap mechanism 340 correspond to... Figure 1 In Embodiment 1, the annular electrode 141 and electrodes 342A and 342B correspond to the end cap electrodes 143 and 145 in Embodiment 1.

[0126] In addition, Figure 11 In this design, the extension direction of each electrode is set as the Z-axis. Furthermore, the relative directions of electrodes 341A and 341B are set as the X-axis, and the relative directions of electrodes 342A and 342B are set as the Y-axis.

[0127] Each electrode is separated into a front section SC1, a middle section SC2, and a rear section SC3 along the Z-axis. The sections are electrically insulated from each other. A groove 350 is formed on the side of electrode 342A, communicating with the space surrounded by the four electrodes.

[0128] Depend on Figure 1 Ions deflected by deflector 130 are introduced into ion trap mechanism 340 through opening 360 on the front section SC1 side along the Z-axis. Then, by setting electrodes 342A and 342B to ground potential and applying a predetermined rectangular wave voltage to electrodes 341A and 341B, the introduced ions are captured in ion trap mechanism 340. Furthermore, a predetermined voltage is applied to the front section SC1 and the rear section SC3 at this time, so that the captured ions remain near the center of the central section SC2 in the Z-axis direction.

[0129] Subsequently, by applying an excitation voltage obtained by frequency division of the rectangular wave voltage applied to electrodes 341A and 341B to electrodes 342A and 342B, ions with a specific mass-to-charge ratio are discharged from the tank 350 in the positive direction of the Y-axis. The discharged ions are then... Figure 1 The detector 150 in the middle detects.

[0130] Thus, even when a linear ion trap is used as an ion trap mechanism, the measurement accuracy may decrease because the rectangular wave voltage applied to electrodes 341A and 341B deviates from the ideal rectangular waveform. Therefore, in the structure of Embodiment 4, the measurement accuracy can be improved by adjusting the resistance value of the gate resistor in the voltage generation circuit that applies voltage to electrodes 341A and 341B according to the mass measurement mode of the standard sample.

[0131] [Postscript]

[0132] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following approaches.

[0133] (First aspect) A mass spectrometry apparatus according to one method relates to an ion trap type mass spectrometry apparatus. The mass spectrometry apparatus includes an ion generation mechanism, an ion trap mechanism, a detector, a voltage generation circuit, and a control device for controlling the voltage generation circuit. The ion generation mechanism supplies ions in a pulsed manner. The ion trap mechanism comprises multiple electrodes, configured to trap ions in an internal space formed by an electric field within the internal space surrounded by the multiple electrodes. The detector detects ions discharged from the ion trap mechanism. The voltage generation circuit applies a voltage to the multiple electrodes. The multiple electrodes include a first electrode and a second electrode, and a high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generation circuit includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies the voltage from the first voltage source to the first electrode. The second switch selectively supplies the voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch, and the first resistor circuit is configured to have a variable resistance value. The second resistor circuit is connected to the control terminal of the second switch, and the second resistor circuit is configured to have a variable resistance value.

[0134] According to the mass spectrometry apparatus described in the first paragraph, the voltage supplied to the ring electrode from two voltage sources can be independently adjusted via a variable resistor circuit located at each control terminal of one of the two switches included in the voltage generation circuit. This voltage generation circuit supplies voltage to the first electrode (ring electrode) included in the ion trap mechanism. Therefore, since the rectangular wave voltage supplied to the ring electrode can be made close to an ideal rectangular wave, deviations in the mass calibration curve that may occur due to mechanical differences in the electronic components constituting the voltage generation circuit can be reduced. Thus, the measurement accuracy in ion trap type mass spectrometry apparatuses can be improved.

[0135] (Second item) In the mass spectrometry analysis device described in the first item, each of the first and second switches is a FET (Field Effect Transistor) with a gate terminal as a control terminal.

[0136] According to the mass spectrometry analysis device involved in the second item, since a general-purpose FET can be used as a switch in the voltage generation circuit, the circuit can be implemented at a lower cost.

[0137] (Third item) In the mass spectrometry analysis apparatus described in the first or second item, each resistor circuit in the first resistor circuit and the second resistor circuit is a semi-adjustable resistor.

[0138] According to the mass spectrometry analysis apparatus involved in the third item, semi-adjustable resistors are used in each resistor circuit, thereby enabling adjustment of the resistance value of the gate resistor.

[0139] (Fourth item) In the mass spectrometry analysis apparatus described in the first or second item, each resistor circuit in the first and second resistor circuits includes multiple resistors connected in series and a bypass circuit. The bypass circuit is controlled by a control device and is configured to selectively bypass a portion of the multiple resistors.

[0140] According to the mass spectrometry analysis device involved in the fourth item, since the resistance value of each resistor circuit can be adjusted according to the control command from the control device, the resistance value adjustment does not need to be turned on the voltage generation circuit.

[0141] (Fifth) In the mass spectrometry analysis apparatus described in the fourth item, the bypass circuit includes multiple switching sections corresponding to multiple resistors. Each resistor circuit in the first resistor circuit and the second resistor circuit is configured such that the resistance value changes as the multiple switching sections are independently switched on and off.

[0142] According to the mass spectrometry analysis apparatus described in item five, the resistance values ​​of each resistor circuit can be adjusted by independently switching the conduction and deconduction of multiple switching sections according to control commands from the control device. Therefore, the resistance values ​​can be adjusted without turning on the voltage generation circuit.

[0143] (Sixth item) In the mass spectrometry analysis apparatus described in the fifth item, the bypass circuit further includes a decoder, which is configured to control a plurality of switching units according to a signal from the control device.

[0144] According to the mass spectrometry analysis device involved in the sixth item, since multiple switching units can be controlled by a decoder, a simpler circuit structure can be used to adjust the resistance value without turning on the voltage generation circuit.

[0145] (Seventh item) In the mass spectrometry analysis apparatus described in the first or second item, each resistor circuit in the first resistor circuit and the second resistor circuit is a digital potentiometer.

[0146] According to the mass spectrometry analysis device involved in item 7, since a common digital potentiometer can be used as a resistor circuit, the resistor circuit can be implemented at a lower cost.

[0147] (Eighth item) In any one of the first to seventh items of the mass spectrometry analysis apparatus, the control device supplies rectangular wave signals with opposite polarities to the control terminals of the first switch and the second switch.

[0148] According to the mass spectrometry apparatus described in item 8, a voltage supplied to the ring electrode can be generated using rectangular wave signals of opposite polarities from the control device.

[0149] (Ninth) The mass spectrometry analyzer described in the eighth item includes a first mode and a second mode as operating modes. (a) In the first mode, the control device supplies a rectangular wave signal of a first polarity to the control terminal of the first switch and supplies a rectangular wave signal of a second polarity opposite to the first polarity to the control terminal of the second switch; (b) In the second mode, the control device supplies a rectangular wave signal of a second polarity to the control terminal of the first switch and supplies a rectangular wave signal of a first polarity to the control terminal of the second switch.

[0150] According to the mass spectrometry analysis apparatus involved in the ninth item, the polarity of the control signals supplied to each switch is reversed by the control device, thereby making it easy to switch between the two measurement modes, positive mode (first mode) and negative mode (second mode).

[0151] (Item 10) In the mass spectrometry analysis apparatus described in Item 9, the first resistive circuit includes a first resistor and a second resistor. The second resistive circuit includes a third resistor and a fourth resistor. In the first mode, (a) the control device supplies a rectangular wave signal of a first polarity to the first resistive circuit and a rectangular wave signal of a second polarity to the second resistive circuit; (b) the rectangular wave signal is supplied to the control terminal of the first switch via the first resistor; and (c) the rectangular wave signal is supplied to the control terminal of the second switch via the third resistor. In the second mode, (d) the control device supplies a rectangular wave signal of a second polarity to the first resistive circuit and a rectangular wave signal of a first polarity to the second resistive circuit; (e) the rectangular wave signal is supplied to the control terminal of the first switch via the second resistor; and (f) the rectangular wave signal is supplied to the control terminal of the second switch via the fourth resistor.

[0152] According to the mass spectrometry apparatus described in item 10, the two measurement modes can be easily switched by changing the polarity of the control signal supplied from the control device, and the gate resistance of each switch can be set independently according to each measurement mode. Therefore, even when switching measurement modes, the deviation of the mass calibration curves of each measurement mode can be reduced, and the measurement accuracy can be improved.

[0153] (Item 11) In the mass spectrometry analyzer described in Item 9, each of the resistor circuits in the first and second resistor circuits is connected to the control terminals of the first and second switches. The first resistor circuit includes a first resistor and a second resistor. The second resistor circuit includes a third resistor and a fourth resistor. In a first mode, (a) a rectangular wave signal is supplied to the control terminal of the first switch via the first resistor, and (b) a rectangular wave signal is supplied to the control terminal of the second switch via the third resistor. In a second mode, (c) a rectangular wave signal is supplied to the control terminal of the second switch via the second resistor, and (d) a rectangular wave signal is supplied to the control terminal of the first switch via the fourth resistor.

[0154] According to the mass spectrometry apparatus described in item eleven, two measurement modes can be easily switched without changing the polarity of the control signal supplied from the control device, and the gate resistance of each switch can be set independently according to each measurement mode. Therefore, even when switching measurement modes, the deviation of the mass calibration curves of each measurement mode can be reduced, and the measurement accuracy can be improved.

[0155] (Item 12) A voltage generating circuit according to one method is used in an ion trap type mass spectrometry apparatus. The mass spectrometry apparatus includes an ion generating mechanism that supplies ions in a pulsed manner, an ion trap mechanism, and a detector. The ion trap mechanism consists of multiple electrodes configured to trap ions in an internal space formed by an electric field in the internal space surrounded by the multiple electrodes. The detector detects ions discharged from the ion trap mechanism. The multiple electrodes include a first electrode and a second electrode. A high-frequency rectangular wave voltage is applied to the first electrode from the voltage generating circuit. The voltage generating circuit includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies voltage from the first voltage source to the first electrode. The second switch selectively supplies voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch and is configured to have a variable resistance value. The second resistor circuit is connected to a control terminal of the second switch and is configured to have a variable resistance value.

[0156] According to the voltage generation circuit described in item 12, the voltage supplied to the ring electrode from two voltage sources can be independently adjusted via a variable resistor circuit provided at each control terminal of the two switches included in the voltage generation circuit. This voltage generation circuit supplies voltage to the first electrode (ring electrode) included in the ion trap mechanism. Therefore, since the rectangular wave voltage supplied to the ring electrode can be made close to an ideal rectangular wave, deviations in the mass calibration curve that may occur due to mechanical differences in the electronic components constituting the voltage generation circuit can be reduced. Thus, the measurement accuracy in ion trap type mass spectrometry analyzers can be improved.

[0157] (Item 13) In the voltage generation circuit described in Item 12, each of the first and second switches is a FET with a gate terminal as a control terminal.

[0158] According to the voltage generation circuit involved in item thirteen, since a general-purpose FET can be used as a switch in the voltage generation circuit, the circuit can be implemented at a lower cost.

[0159] (Item 14) In the voltage generating circuit described in Item 12 or Item 13, each resistor circuit in the first resistor circuit and the second resistor circuit is a semi-adjustable resistor.

[0160] According to the voltage generation circuit involved in item fourteen, semi-adjustable resistors are used in each resistor circuit, thereby enabling adjustment of the resistance value of the gate resistor.

[0161] (Item 15) In the voltage generating circuit described in Item 12 or Item 13, each resistor circuit in the first resistor circuit and the second resistor circuit includes a plurality of resistors connected in series and a bypass circuit. The bypass circuit is controlled by a control device and is configured to selectively bypass a portion of the plurality of resistors.

[0162] According to the voltage generating circuit involved in item 15, since the resistance value of each resistor circuit can be adjusted according to the control command from the control device, the resistance value can be adjusted without opening the voltage generating circuit.

[0163] (Item 16) In the voltage generating circuit described in Item 15, the bypass circuit includes multiple switching sections corresponding to multiple resistors. Each resistor circuit in the first resistor circuit and the second resistor circuit is configured such that the resistance value changes as the multiple switching sections are independently switched on and off.

[0164] According to the voltage generating circuit described in item sixteen, the resistance value of each resistor circuit can be adjusted by independently switching the conduction and deconduction of multiple switching sections according to control commands from the control device. Therefore, the resistance value can be adjusted without turning on the voltage generating circuit.

[0165] (Item 17) In the voltage generation circuit described in Item 16, the bypass circuit further includes a decoder, which is configured to control a plurality of switching units according to a signal from an external control device.

[0166] According to the voltage generation circuit involved in item 17, since multiple switching units can be controlled by a decoder, a simpler circuit structure can be used to adjust the resistance value without opening the voltage generation circuit.

[0167] (Item 18) In the voltage generating circuit described in Item 12 or Item 13, each resistor circuit in the first resistor circuit and the second resistor circuit is a digital potentiometer.

[0168] According to the voltage generation circuit involved in item 18, since a common digital potentiometer can be used as a resistor circuit, the resistor circuit can be implemented at a lower cost.

[0169] (Item 19) One method relates to a method for controlling an ion trap type mass spectrometry apparatus. The mass spectrometer includes an ion trap mechanism and a voltage generation circuit. The ion trap mechanism comprises a plurality of electrodes, configured to trap ions in an internal space formed by an electric field in an internal space surrounded by the plurality of electrodes. The voltage generation circuit applies a voltage to the plurality of electrodes. The plurality of electrodes includes a first electrode and a second electrode, and a high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generation circuit includes a first voltage source and a second voltage source, a first switch and a second switch, and a first resistor circuit and a second resistor circuit. The voltage of the second voltage source is lower than the voltage of the first voltage source. The first switch selectively supplies the voltage from the first voltage source to the first electrode. The second switch selectively supplies the voltage from the second voltage source to the first electrode. The first resistor circuit is connected to a control terminal of the first switch. The second resistor circuit is connected to a control terminal of the second switch. The method includes the following steps: i) measuring the mass accuracy using a standard sample; ii) determining whether the measured mass accuracy of the standard sample is within a reference range; and iii) if the mass accuracy of the standard sample is not within a reference range, adjusting the resistance value of at least one of the first and second resistor circuits to bring the mass accuracy within a reference range.

[0170] (Item 20) In the method described in Item 19, the adjustment amount of the resistance values ​​of the first and second resistance circuits is determined in advance according to the mass accuracy mode. The method further includes the step of determining the adjustment amount of the resistance values ​​of the first and second resistance circuits based on the measurement mode of the mass accuracy of the measured standard sample.

[0171] (Item 21) In the mass spectrometry apparatus described in Item 1, when ions are captured using an ion trap mechanism, the second electrode is set to a ground potential. When a specific ion is discharged from the ion trap mechanism, a voltage corresponding to the frequency of that specific ion is applied to the second electrode from a voltage generation circuit.

[0172] The embodiments disclosed herein should be considered illustrative rather than limiting in all respects. The scope of the invention is defined by the claims rather than by the description of the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0173] Explanation of reference numerals in the attached figures

[0174] 10 Mass spectrometry analyzer; 100 Measuring section; 105 Chamber; 107 Window; 110 Sample stage; 115 Sample plate; 120 Extraction electrode; 130 Deflector; 140, 340 Ion trap mechanism; 141 Ring electrode; 142, 144 End cap electrode; 143 Entrance port; 145 Exit port; 146 Internal space; 150 Detector; 160 Vacuum pump; 170 Laser irradiation section; 180, 180A~180C Voltage generation circuit; 181 High-voltage side power supply; 182 Low-voltage side power supply; 183, 183A~183C Switching circuit; 184 Decoder; 185 Gas supply section; 190 Operation section; 195 Display section; 200 Control device; 210 CPU; 220 Memory; 230 Interface; 240 Communication bus; Electrodes 341A, 341B, 342A, 342B; 350 slot; 360 opening; BF1, BF2 buffers; BP1, BP2 bypass circuits; M10 motor; N1~N9, ND1 connection nodes; R1, R1P, R1N, R2, R2P, R2N, R3, R11~R20 resistors; RC1, RC1A~RC1E, RC2, RC2A, RC2D, RC2E resistor circuits; RY1, RY2 relays; SC1 front section; SC2 central section; SC3 rear section; SP sample; SW1, SW2, TR1~TR8 switches; T1~T5 terminals; TM1 trimmer.

Claims

1. A mass spectrometry analysis device, which is an ion trap type mass spectrometry analysis device, said mass spectrometry analysis device comprising: An ion generating mechanism that supplies ions in a pulsed manner; An ion trap mechanism comprising a plurality of electrodes, the ion trap mechanism being configured to trap ions in an internal space by means of an electric field formed in an internal space surrounded by the plurality of electrodes; A detector that detects ions discharged from the ion trap mechanism; A voltage generating circuit applies a voltage to the plurality of electrodes; and A control device that controls the voltage generating circuit. in, The plurality of electrodes includes a first electrode and a second electrode. A high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generating circuit includes: First voltage source; The second voltage source has a lower voltage than the first voltage source. A first switch selectively supplies voltage from the first voltage source to the first electrode; The second switch selectively supplies voltage from the second voltage source to the first electrode; A first resistor circuit, connected to the control terminal of the first switch, is configured to have a variable resistance value; and A second resistor circuit is connected to the control terminal of the second switch, and the second resistor circuit is configured to have a variable resistance value.

2. The mass spectrometry analysis apparatus according to claim 1, wherein, Each of the first and second switches is a FET (Field-Effect Transistor) with a gate terminal as a control terminal.

3. The mass spectrometry analysis apparatus according to claim 1 or 2, wherein, Each resistor in the first resistor circuit and the second resistor circuit is a semi-adjustable resistor.

4. The mass spectrometry analysis apparatus according to claim 1 or 2, wherein, Each resistor circuit in the first resistor circuit and the second resistor circuit includes: Multiple resistors, the multiple resistors being connected in series; and A bypass circuit, controlled by the control device, is configured to selectively bypass a portion of the plurality of resistors.

5. The mass spectrometry analysis apparatus according to claim 4, wherein, The bypass circuit includes multiple switching sections corresponding to the plurality of resistors. Each resistor circuit in the first resistor circuit and the second resistor circuit is configured such that the resistance value changes as the conduction and non-conduction of the plurality of switching sections are switched independently.

6. The mass spectrometry analysis apparatus according to claim 5, wherein, The bypass circuit also includes a decoder configured to control the plurality of switching units according to signals from the control device.

7. The mass spectrometry analysis apparatus according to claim 1 or 2, wherein, Each resistor in the first resistor circuit and the second resistor circuit is a digital potentiometer.

8. The mass spectrometry analysis apparatus according to claim 1 or 2, wherein, The control device supplies rectangular wave signals with opposite polarities to the control terminals of the first switch and the second switch.

9. The mass spectrometry analysis apparatus according to claim 8, wherein, The mass spectrometry analysis device includes a first mode and a second mode as operating modes. In the first mode, the control device supplies a rectangular wave signal of first polarity to the control terminal of the first switch, and supplies a rectangular wave signal of second polarity with the opposite polarity to the control terminal of the second switch. In the second mode, the control device supplies a rectangular wave signal of the second polarity to the control terminal of the first switch and a rectangular wave signal of the first polarity to the control terminal of the second switch.

10. The mass spectrometry analysis apparatus according to claim 9, wherein, The first resistor circuit includes a first resistor and a second resistor. The second resistor circuit includes a third resistor and a fourth resistor. In the first mode, the control device supplies a rectangular wave signal of the first polarity to the first resistor circuit and a rectangular wave signal of the second polarity to the second resistor circuit. The rectangular wave signal is supplied to the control terminal of the first switch via the first resistor, and the rectangular wave signal is supplied to the control terminal of the second switch via the third resistor. In the second mode, the control device supplies a rectangular wave signal of the second polarity to the first resistor circuit and a rectangular wave signal of the first polarity to the second resistor circuit. The rectangular wave signal is supplied to the control terminal of the first switch via the second resistor and to the control terminal of the second switch via the fourth resistor.

11. The mass spectrometry analysis apparatus according to claim 9, wherein, Each resistor in the first resistor circuit and the second resistor circuit is connected to the control terminals of the first switch and the second switch. The first resistor circuit includes a first resistor and a second resistor. The second resistor circuit includes a third resistor and a fourth resistor. In the first mode, a rectangular wave signal is supplied to the control terminal of the first switch via the first resistor, and a rectangular wave signal is supplied to the control terminal of the second switch via the third resistor. In the second mode, a rectangular wave signal is supplied to the control terminal of the second switch via the second resistor, and a rectangular wave signal is supplied to the control terminal of the first switch via the fourth resistor.

12. A voltage generating circuit for use in an ion trap type mass spectrometry analyzer. The mass spectrometry analysis device includes: An ion generating mechanism that supplies ions in a pulsed manner; An ion trap mechanism comprising a plurality of electrodes, the ion trap mechanism being configured to trap ions in an internal space by means of an electric field formed in an internal space surrounded by the plurality of electrodes; as well as A detector that detects ions discharged from the ion trap mechanism. The plurality of electrodes includes a first electrode and a second electrode. A high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generating circuit includes: First voltage source; The second voltage source has a lower voltage than the first voltage source. A first switch selectively supplies voltage from the first voltage source to the first electrode; The second switch selectively supplies voltage from the second voltage source to the first electrode; A first resistor circuit, connected to the control terminal of the first switch, is configured to have a variable resistance value; and A second resistor circuit is connected to the control terminal of the second switch, and the second resistor circuit is configured to have a variable resistance value.

13. The voltage generating circuit according to claim 12, wherein, Each of the first and second switches is a FET (Field-Effect Transistor) with a gate terminal as a control terminal.

14. The voltage generating circuit according to claim 12 or 13, wherein, Each resistor in the first resistor circuit and the second resistor circuit is a semi-adjustable resistor.

15. The voltage generating circuit according to claim 12 or 13, wherein, Each resistor circuit in the first resistor circuit and the second resistor circuit includes: Multiple resistors, the multiple resistors being connected in series; and A bypass circuit, controlled by a control device, is configured to selectively bypass a portion of the plurality of resistors.

16. The voltage generating circuit according to claim 15, wherein, The bypass circuit includes multiple switching sections corresponding to the plurality of resistors. Each resistor circuit in the first resistor circuit and the second resistor circuit is configured such that the resistance value changes as the conduction and non-conduction of the plurality of switching sections are switched independently.

17. The voltage generating circuit according to claim 16, wherein, The bypass circuit also includes a decoder configured to control the plurality of switching units according to signals from an external control device.

18. The voltage generating circuit according to claim 12 or 13, wherein, Each resistor in the first resistor circuit and the second resistor circuit is a digital potentiometer.

19. A method for controlling an ion trap type mass spectrometry analyzer. The mass spectrometry analysis device includes: An ion trap mechanism comprising a plurality of electrodes, the ion trap mechanism being configured to trap ions in an internal space by means of an electric field formed in an internal space surrounded by the plurality of electrodes; as well as A voltage generating circuit applies a voltage to the plurality of electrodes. The plurality of electrodes includes a first electrode and a second electrode. A high-frequency rectangular wave voltage is applied to the first electrode from the voltage generation circuit. The voltage generating circuit includes: First voltage source; The second voltage source has a lower voltage than the first voltage source. A first switch selectively supplies voltage from the first voltage source to the first electrode; The second switch selectively supplies voltage from the second voltage source to the first electrode; A first resistor circuit, which is connected to the control terminal of the first switch; and The second resistor circuit is connected to the control terminal of the second switch. The method includes the following steps: Use standard samples to measure mass accuracy; Determine whether the measured mass accuracy of the standard sample is within the reference range; and If the mass accuracy of the standard sample is not within the reference range, adjust the resistance value of at least one of the first resistor circuit and the second resistor circuit to bring the mass accuracy within the reference range.

20. The method according to claim 19, wherein, The adjustment amount of the resistance values ​​of the first resistor circuit and the second resistor circuit is determined in advance according to the quality accuracy mode. The method further includes the following steps: determining the adjustment amount of the resistance values ​​of the first resistor circuit and the second resistor circuit based on the measurement mode of the measured mass accuracy of the standard sample.

21. The mass spectrometry analysis apparatus according to claim 1, wherein, When using the ion trap mechanism to capture ions, the second electrode is set to ground potential. When a specific ion is discharged from the ion trap mechanism, a voltage corresponding to the frequency of the specific ion is applied to the second electrode from the voltage generating circuit.

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