Quadrupole mass analysis device, method, and program recording medium

Abstract

The present invention provides a quadrupole mass analysis device and method, and a program recording medium. The quadrupole mass analysis device comprises: an ion source (1) for ionizing a sample; a filter unit (3) having a quadrupole (31) and separating the mass of ions generated in the ion source (1); a detector (5) for detecting ions that have passed through the filter unit (3); a filter voltage controller (62) for controlling a filter voltage composed of a high-frequency voltage and a direct current voltage applied to the quadrupole (31), and switching between a blocking mode and an incident mode, wherein the blocking mode prevents ions incident on the filter unit (3) from being incident on the detector, and the incident mode allows ions incident on the filter unit (3) to be incident on the detector; a baseline calculation unit (63) for calculating a baseline based on the output of the detector in the blocking mode; and an analysis unit (65) for outputting an analysis result of the sample based on the output of the detector in the incident mode and the baseline calculated by the baseline calculation unit (63).

Description

Technical Field

[0001] The invention relates to a quadrupole mass analysis device. Background Art

[0002] The quadrupole mass analyzer has: an ion source that ionizes a sample; a filter unit that has a quadrupole and performs mass separation on ions incident from the ion source; and a detector that detects ions that have passed through the filter unit. A filter voltage that combines a high-frequency voltage (RF) and a direct current voltage (DC) at a predetermined ratio is applied to the quadrupole based on the Mathieu equation, and the filter unit functions as a mass filter. In addition, by scanning the filter voltage from the low voltage side to the high voltage side while maintaining the above-mentioned predetermined ratio, the mass spectrum of the ions is obtained from the output of the detector.

[0003] In addition, in a quadrupole mass spectrometer, baseline processing is performed in order to reduce the noise generated by neutral molecules from the obtained mass spectrum or to correct the offset from the zero point. For example, in Patent Document 1, an incident period in which ions are incident on the detector and a blocking period in which ions are not incident on the detector are provided, and baseline processing is performed by subtracting the signal obtained from the detector during the blocking period from the signal obtained from the detector during the incident period. More specifically, the incident period and the blocking period are achieved by changing the potential of the post-filter disposed at the rear stage of the quadrupole. In addition, as another method, changing the potential difference between the ion source and the filter section can be listed so that the ions generated in the ion source are not incident on the filter section at the beginning, so that the ions cannot be detected by the detector.

[0004] However, even if the blocking period is achieved by not allowing ions to enter the detector using the above methods, sometimes a larger signal is generated in the detector output, especially in the part with a smaller mass-to-charge ratio than in other parts. Therefore, even if the output of the detector during the blocking period is simply subtracted from the output of the detector during the incident period, sometimes it will not be an appropriate baseline processing.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Patent No. 5412246 Summary of the invention

[0008] Technical issues

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a quadrupole mass spectrometer that can reliably prevent ions from entering a detector and perform appropriate baseline processing.

[0010] Technical Solution

[0011] That is, the quadrupole mass spectrometer of the present invention is characterized in that it comprises: an ion source, which ionizes a sample; a filter section, which comprises a quadrupole and separates the mass of ions generated in the ion source; a detector, which detects ions that have passed through the filter section; a filter voltage controller, which controls the filter voltage composed of a high-frequency voltage and a direct current voltage applied to the quadrupole, and switches between a blocking mode and an incident mode, wherein the blocking mode prevents ions incident on the filter section from being incident on the detector, and the incident mode causes ions incident on the filter section to be incident on the detector; a baseline calculation section, which calculates a baseline based on the output of the detector in the blocking mode; and an analysis section, which outputs the analysis result of the sample based on the output of the detector in the incident mode and the baseline calculated by the baseline calculation section.

[0012] In addition, the quadrupole mass analysis method of the present invention is characterized in that it is an analysis method for a quadrupole mass analysis device, wherein the quadrupole mass analysis device comprises: an ion source, which ionizes a sample; a filter section, which comprises a quadrupole and separates the mass of ions generated in the above-mentioned ion source; and a detector, which detects ions that have passed through the above-mentioned filter section, and the quadrupole mass analysis method comprises: a filter voltage control step, which controls the filter voltage composed of a high-frequency voltage and a direct current voltage applied to the above-mentioned quadrupole, and switches between a blocking mode and an incident mode, wherein the blocking mode prevents ions incident on the above-mentioned filter section from being incident on the above-mentioned detector, and the incident mode causes ions incident on the above-mentioned filter section to be incident on the above-mentioned detector; a baseline calculation step, which calculates a baseline based on the output of the above-mentioned detector in the above-mentioned blocking mode; and an analysis step, which outputs the analysis result of the sample based on the output of the above-mentioned detector in the above-mentioned incident mode and the baseline calculated in the above-mentioned baseline calculation step.

[0013] If so, the filter voltage controller controls the filter voltage applied to the quadrupole in such a way that the ions are not incident on the detector. This makes the vibration of the ions in the filter section unstable so that the ions passing through the filter section collide with the quadrupole, or changes the trajectory of the ions in such a way that the ions are not incident on the detector. Therefore, the ions can be reliably prevented from being incident on the detector in the blocking mode. Therefore, it is possible to achieve a state in which the output of the detector in the blocking mode is completely unaffected by the ions, and to obtain a baseline that only shows noise and / or temperature drift, such as those generated by neutrons. Therefore, the analysis result of the sample obtained by the analysis section can be the result of more effective baseline processing than before.

[0014] In order to obtain a clear peak from the output of the detector for each mass-to-charge ratio in the above-mentioned incident mode and to prevent ions from being incident in the above-mentioned blocking mode, the above-mentioned filter voltage controller can scan the filter voltage in a manner passing through a stable region in the above-mentioned incident mode and scan the filter voltage in a manner passing through outside the above-mentioned stable region in the above-mentioned blocking mode. The stable region refers to a set of combinations of high-frequency voltage and DC voltage that allow ions to pass through the above-mentioned filter portion and reach the above-mentioned detector.

[0015] As a scanning method of the filter voltage suitable for mass separation in the above-mentioned incident mode, it can be listed that the above-mentioned filter voltage controller scans the filter voltage in the above-mentioned incident mode in a manner near the vertex where the DC voltage is maximum relative to the high-frequency voltage in the above-mentioned multiple stable regions determined for each ion mass-to-charge ratio.

[0016] In order to prevent ions in the blocking mode from entering the detector in the entire bandwidth of the mass-to-charge ratio to be analyzed, the filter voltage controller can scan the filter voltage in the blocking mode in a manner outside all areas of the multiple stable areas determined for each ion mass-to-charge ratio.

[0017] As a specific method for performing a voltage scanning operation corresponding to the above-mentioned incident mode also in the above-mentioned blocking mode while reliably preventing ions from incident on the above-mentioned detector, it can be listed that the above-mentioned filter voltage controller sets the slope of the DC voltage of the filter voltage scanned in the above-mentioned blocking mode relative to the high-frequency voltage to be larger than the slope of the DC voltage of the filter voltage scanned in the above-mentioned incident mode relative to the high-frequency voltage.

[0018] In order to ensure that there is no difference between the above-mentioned incident mode and the above-mentioned blocking mode except for the voltage applied to the above-mentioned quadrupole, and to ensure that the baseline obtained in the above-mentioned blocking mode is also well reproduced in the above-mentioned incident mode, the quadrupole mass analysis device may further include: an ion ejection electrode, which forms an electric field to draw ions from the above-mentioned ion source and allow the ions to be incident on the above-mentioned filter section, and the same voltage can be applied to the ion ejection electrode in any mode of the above-mentioned incident mode and the above-mentioned blocking mode.

[0019] In order to enable an existing quadrupole mass spectrometer to enjoy the same effect as that of the quadrupole mass spectrometer of the present invention by simply updating the program, a program for a quadrupole mass spectrometer can be used. The program is a program for a quadrupole mass spectrometer, wherein the quadrupole mass spectrometer includes: an ion source that ionizes a sample; a filter section that includes a quadrupole and separates the mass of ions generated in the above-mentioned ion source; and a detector that detects ions that have passed through the above-mentioned filter section. The program for a quadrupole mass spectrometer is characterized in that a computer is caused to function as a filter voltage controller, a baseline calculation section, and an analysis section, the filter voltage controller controls a filter voltage composed of a high-frequency voltage and a direct current voltage applied to the above-mentioned quadrupole, and switches between a blocking mode and an incident mode, the blocking mode preventing ions incident on the above-mentioned filter section from being incident on the above-mentioned detector, and the incident mode causing ions incident on the above-mentioned filter section to be incident on the above-mentioned detector, the baseline calculation section calculating a baseline based on an output of the above-mentioned detector in the above-mentioned blocking mode, and the analysis section outputting an analysis result of the sample based on the output of the above-mentioned detector in the above-mentioned incident mode and the baseline calculated by the baseline calculation section.

[0020] In addition, the program for quadrupole mass spectrometer may be distributed electronically, or may be recorded on a program recording medium such as a CD, a DVD, or a flash memory.

[0021] Technical Effects

[0022] In the case of the quadrupole mass spectrometer of the present invention, since the filter voltage applied to the quadrupole in the blocking mode is controlled, the ions can be prevented from entering the detector more reliably than before. As a result, the occurrence of unexplained output on the obtained baseline can be greatly reduced, and the reliability of the baseline can be improved. Furthermore, the validity of the analysis result of the sample obtained based on the output of the detector and the baseline obtained in the incident mode can also be improved than before. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a diagram showing a state where a quadrupole mass spectrometer according to an embodiment of the present invention is installed in a vacuum chamber.

[0024] Figure 2 It is a schematic perspective view showing the structure of the quadrupole mass spectrometer according to this embodiment.

[0025] Figure 3 It is a schematic diagram showing the configuration of the quadrupole mass spectrometer and the overall potential gradient according to this embodiment.

[0026] Figure 4 : is a functional block diagram showing the configuration of the quadrupole mass spectrometer according to this embodiment.

[0027] Figure 5 is a schematic diagram showing the relationship between the filter voltage and the stable region.

[0028] Figure 6 Schematic diagram showing the relationship between the scanning straight line of the filter voltage scanned in each of the incident mode and the blocking mode in this embodiment and the stable region of each mass-to-charge ratio.

[0029] Figure 7 It is a schematic diagram showing an output example of the detector and an analysis result example of the analysis unit in the incident mode and the blocked mode in this embodiment.

[0030] Explanation of symbols

[0031] 100…Quadrupole mass analyzer

[0032] 1…Ion source

[0033] 2…Leader electrode

[0034] 3…Filtration

[0035] 31…Quadrupole

[0036] 5…Detector

[0037] 62…Filter voltage controller

[0038] 63…Baseline calculation department

[0039] 65…Analysis Department DETAILED DESCRIPTION

[0040] Reference Figures 1 to 7 A quadrupole mass spectrometer 100 according to one embodiment of the present invention will be described.

[0041] like Figure 1 As shown, the quadrupole mass spectrometer 100 of the present embodiment is installed in a vacuum chamber VC such as a semiconductor process chamber, and is used as a residual gas analysis device for analyzing residual gas in the chamber VC.

[0042] The quadrupole mass spectrometer 100 includes a housing C and a Figure 2 The sensor mechanism SN and the control operation mechanism 6 (not shown) are shown in FIG. Figure 1 and Figure 2 ).

[0043] like Figure 1As shown, the housing C comprises: a first cover C1 which is installed in a manner that its front end surface is arranged inside the chamber VC to accommodate the sensor mechanism SN; and a second cover C2 which is arranged outside the chamber VC to accommodate the control operation mechanism 6. A gas introduction port for introducing the gas in the chamber VC into the sensor mechanism SN is formed at the front end surface of the first cover C1 arranged in the chamber VC.

[0044] like Figure 2 and Figure 3 As shown, the sensor mechanism SN includes: an ion source 1, which ionizes a sample introduced from a gas inlet by electron collision; an extraction electrode 2, which extracts ions generated in the ion source 1, accelerates and focuses the ions; a filter 3, which separates the ions accelerated and focused by the extraction electrode 2 according to the mass-to-charge ratio by a high-frequency electric field generated by a quadrupole 31 as four cylindrical electrodes; a detector 5, which detects the ions separated by the filter 3, and outputs a current value corresponding to the number of detected ions as an output to a control operation mechanism 6; and a post-filter 4, which is provided between the filter 3 and the detector 5. These components are arranged in a row along the traveling direction of the ions.

[0045] The sensor mechanism SN of this embodiment operates in at least two modes: an incident mode for causing ions to enter the detector 5 and a blocking mode for preventing ions from entering the detector 5 . Switching between these modes is achieved by changing the filter voltage applied to the quadrupole 31 of the filter unit 3 .

[0046] Molecules existing in the chamber VC are introduced as samples into the ion source 1 and ionized by electrons emitted from the electron gun 11. The electron gun 11 emits electrons in both the incident mode and the blocking mode, and the molecules incident into the ion source 1 are always ionized.

[0047] In the quadrupole 31 of the filter unit 3, filtering voltages of the same polarity are applied to electrodes facing each other, and voltages of opposite polarity are applied to adjacent electrodes. Figure 2 As shown in (a), it is composed of DC voltage and high-frequency voltage. Figure 2 The amplitude of the DC voltage and the amplitude of the high-frequency voltage shown in (b) are respectively swept from the low voltage side to the high voltage side. The details of the filter voltage in the incident mode and the blocking mode will be described later.

[0048] Figure 2 and Figure 3 The detector 5 shown is, for example, a Faraday cup which generates a current corresponding to the number of incident ions.

[0049] Figure 4The control operation mechanism 6 shown in the figure has a computer including an amplifier, an A / D converter, a D / A converter, a CPU, a memory, a communication port, etc. The control operation mechanism 6 performs mass analysis based on the current value as the output of the detector 5. In addition, the analysis result is sent to a general-purpose computer, etc. as needed.

[0050] Specifically, the control operation mechanism 6 executes the quadrupole mass analyzer program stored in the memory through the CPU, and cooperates with various devices to play a role. Figure 4 As shown in the functional block diagram, at least the functions of the extraction voltage controller 61, the filter voltage controller 62, the baseline calculation unit 63, the baseline storage unit 64, the analysis unit 65, and the mode switching unit 66 are provided.

[0051] Describe each part in detail.

[0052] The extraction voltage controller 61 controls the voltage applied to the extraction electrode 2. Figure 3 As shown in the schematic diagram of FIG. 1 , the extraction voltage controller 61 applies a voltage to the extraction electrode 2 in such a manner that the potential in the filter 3 becomes lower relative to the ion source 1. It should be noted that the voltage is applied to the post filter 4 in such a manner that the potential on the detector 5 side becomes lower relative to the filter 3. The extraction voltage controller 61 is configured to keep the potential difference between the filter 3 and the ion source 1 the same regardless of the incident mode or the blocking mode. It should be noted that, in the prior art, the filter 3 is controlled to have a higher potential than the ion source 1 in such a manner that the ions are not incident on the detector 5.

[0053] like Figure 4 As shown, the filter voltage controller 62 controls the filter voltage applied to the quadrupole 31. Specifically, in the incident mode, the filter voltage controller 62 applies the filter voltage to the quadrupole 31 in such a manner that the ions in the filter section 3 move in a stable vibration and are incident on the detector 5 (hereinafter, the filter voltage applied to the quadrupole 31 in the incident mode is also referred to as the incident filter voltage). On the other hand, in the blocking mode, the filter voltage controller 62 applies the filter voltage to the quadrupole 31 in such a manner that the ions in the filter section 3 move in an unstable orbit, for example, so that the ions collide with the quadrupole 31 or detach from the outside of the detector 5 (hereinafter, the filter voltage applied to the quadrupole 31 in the blocking mode is also referred to as the blocking filter voltage).

[0054] Next, refer to Figure 5 and Figure 6 The incident filter voltage and the blocking filter voltage are described in detail.

[0055] In the incident mode, the incident filter voltage applied to the quadrupole 31 is to pass Figure 5 and Figure 6 The area represented by the hatched line in the figure, i.e., the roughly triangular stable area, is scanned in a manner. Here, the stable area refers to a set of combinations of high-frequency voltage (RF voltage) and direct current voltage (DC voltage) that allow ions to pass through the filter section 3 and reach the detector 5. The stable area is determined separately for each ion mass-to-charge ratio that is the object of analysis based on the Mathieu equation. Because the frequency of the high-frequency voltage is fixed at a predetermined value in the present embodiment, the stable area is defined by the amplitude of the DC voltage and the amplitude of the high-frequency voltage. In actual analysis, the ratio of the high-frequency voltage to the DC voltage is set in such a way that only ions of one mass-to-charge ratio are incident on the detector 5 when a certain incident filter voltage is applied to the quadrupole 31. Specifically, as Figure 6 As shown, the incident filter voltage is scanned on the first scanning line SL1 which is set in a manner to pass through the vicinity of the apex of the stable region of each mass-to-charge ratio. Here, the apex of the stable region refers to the point where the DC voltage is the largest relative to the high-frequency voltage in the combination of the high-frequency voltage and the DC voltage at which ions can be incident on the detector 5. Since the first scanning line SL1 alternately enters and exits each stable region and outside the stable region, if the incident filter voltage is scanned along the first scanning line SL1, the period in which ions are detected and the period in which ions are not detected appear alternately. In addition, as far as ions are concerned, they are incident on the detector 5 in order from the smallest mass-to-charge ratio.

[0056] On the other hand, in the blocking mode, the blocking filter voltage applied to the quadrupole 31 is scanned along the second scanning straight line SL2 passing only through the outer sides of each stable region. Figure 6 The slope of the second scanning line SL2 is set larger than that of the first scanning line SL1. In other words, under the condition that the high frequency voltage has the same value, the DC voltage value of the blocking filter voltage is set larger than the DC voltage value of the incident filter voltage.

[0057] Figure 4 The baseline calculation unit 63 shown in FIG. 1 calculates the baseline based on the output of the detector 5 when the filter voltage controller 62 applies the blocking filter voltage to the quadrupole 31. For example, the baseline calculation unit 63 is, for example Figure 7 As shown in (a), based on the data indicating the relationship between the current value output from the detector 5 and the high frequency voltage when the blocking filter voltage is scanned along the second scanning straight line SL2 and the relationship between the mass-to-charge ratio at which the mass separation is performed if the incident filter voltage is applied to the high frequency voltage, the current value output when no ions are detected is used as the baseline to calculate corresponding to each mass-to-charge ratio. The calculated baseline is stored in the baseline storage unit 64 and is used for calculation in the analysis unit 65.

[0058] The analysis unit 65 outputs the analysis result of the sample based on the output of the detector 5 and the baseline when the filter voltage controller 62 applies the incident filter voltage to the quadrupole 31. The analysis unit 65 calculates, for example, Figure 7 The relationship between the current value and the mass-to-charge ratio of the detector 5 when the incident filter voltage is scanned along the first scanning straight line SL1 shown in (b) is calculated, and the baseline is subtracted from the calculation result to calculate Figure 7 (c) shows a mass spectrum in which the current value is substantially zero except for the mass-to-charge ratio to be analyzed.

[0059] The mode switching unit 66 switches the operation mode of the filter voltage controller 62, the baseline calculation unit 63, and the analysis unit 65 between the incident mode and the blocking mode. In this embodiment, the filter voltage controller 62, the baseline calculation unit 63, and the analysis unit 65 are operated in the blocking mode immediately after the analysis of the sample is started, and the baseline is calculated by the baseline calculation unit 63. If the baseline is calculated, the mode switching unit 66 operates each unit in the incident mode, and the analysis unit 65 outputs the mass spectrum of the sample.

[0060] In this way, in the blocking mode for generating a baseline, the filter voltage controller 62 of the quadrupole mass spectrometer 100 of the present embodiment scans the blocking filter voltage on the quadrupole 31 along the second scanning straight line SL2 in a manner that deviates from the stable region of all mass-to-charge ratios. In this way, the ions are not introduced into the detector 5 by the electric field formed by the quadrupole 31 of the filter section 3, so that the ions can be prevented from entering the detector 5 more reliably than before when generating a baseline. In other words, the voltage condition in the quadrupole mass spectrometer 100 in the blocking mode is set so that the ions enter the filter section 3 and the ions do not reach the detector 5 from the filter section 3. By setting such a voltage condition, the difference between the baseline in the output of the detector 5 in the blocking mode and the baseline in the output of the detector 5 in the incident mode can be reduced.

[0061] As a result, the validity of the baseline calculated by the baseline calculation unit 63 can be improved, and the reliability of the analysis result of the sample can also be improved.

[0062] Other implementation modes will be described.

[0063] The quadrupole is not limited to being composed of four cylindrical electrodes, but may be a cylinder having a hyperbolic inner surface.

[0064] The blocking filter voltage is not limited to the above embodiment. That is, it is not limited to scanning along the second scanning line, but can also be scanned along other lines. In other words, the scanning line when scanning the blocking filter voltage can be set to pass only outside the stable area.

[0065] The application of the quadrupole mass spectrometer of the present invention is not limited to the residual gas analysis device in the chamber, and can be used, for example, to perform quantitative analysis of samples together with a gas chromatograph or the like.

[0066] For the extraction electrode, although the applied voltage is not changed in either the incident mode or the blocking mode, the filter section may be made higher in potential than the ion source in the blocking mode, and the blocking filter voltage may be scanned on the quadrupole. Alternatively, the blocking filter voltage may be scanned on the quadrupole, and the detector may be made higher in potential than the filter section by applying a voltage to the post-filter.

[0067] Furthermore, the present invention may modify the embodiments or combine parts of the embodiments within a scope not departing from the gist of the present invention.

Claims

1. A quadrupole mass analyzer, characterized in that: have: an ion source, which ionizes the sample; A filter unit having a quadrupole and separating the masses of ions generated in the ion source; a detector for detecting ions that have passed through the filter; A filter voltage controller, which controls the filter voltage composed of a high-frequency voltage and a direct current voltage applied to the quadrupole, and switches between a blocking mode and an incident mode, wherein the blocking mode prevents the ions incident to the filter section from being incident to the detector, and the incident mode allows the ions incident to the filter section to be incident to the detector; a baseline calculation section that calculates a baseline based on an output of the detector in the blocking mode; as well as an analysis unit that outputs an analysis result of a sample based on the output of the detector in the incident mode and the baseline calculated by the baseline calculation unit, The filter voltage controller scans the filter voltage in the blocking mode so as to pass outside a stable region, wherein the stable region refers to a set of combinations of high frequency voltage and direct current voltage that allow ions to pass through the filter portion and reach the detector.

2. The quadrupole mass spectrometer according to claim 1, characterized in that: The filter voltage controller sweeps the filter voltage through the stable region in the incident mode.

3. The quadrupole mass spectrometer according to claim 1, characterized in that: The filter voltage controller sweeps the filter voltage in the incident mode in a manner that passes through a vertex or its vicinity where the DC voltage is maximum with respect to the high frequency voltage in each of the plurality of stable regions determined for each ion mass-to-charge ratio.

4. The quadrupole mass analyzer according to claim 2, characterized in that: The filter voltage controller scans the filter voltage in the blocking mode in a manner passing outside all of the plurality of stable regions determined for each ion mass-to-charge ratio.

5. The quadrupole mass analyzer according to claim 1, characterized in that: The filter voltage controller sets a slope of a DC voltage of the filter voltage scanned in the blocking mode with respect to a high frequency voltage to be greater than a slope of a DC voltage of the filter voltage scanned in the incident mode with respect to a high frequency voltage.

6. The quadrupole mass analyzer according to claim 1, characterized in that: The device further comprises an ion ejection electrode, the ion ejection electrode forming an electric field for extracting ions from the ion source and causing the ions to enter the filter unit. The same voltage is applied to the ion ejection electrode in either the incident mode or the blocking mode.

7. A quadrupole mass analysis method, characterized in that: The invention is an analysis method for a quadrupole mass analyzer, wherein the quadrupole mass analyzer comprises: an ion source, which ionizes the sample; A filter unit having a quadrupole and separating the masses of ions generated in the ion source; as well as a detector for detecting ions that have passed through the filter portion, The quadrupole mass analysis method has: A filtering voltage control step, controlling the filtering voltage composed of a high-frequency voltage and a direct current voltage applied to the quadrupole, switching between a blocking mode and an incident mode, wherein the blocking mode prevents the ions incident to the filtering portion from being incident to the detector, and the incident mode allows the ions incident to the filtering portion to be incident to the detector; a baseline calculation step of calculating a baseline based on the output of the detector in the blocking mode; as well as an analysis step of outputting an analysis result of a sample based on the output of the detector in the incident mode and the baseline calculated in the baseline calculation step, The filter voltage control step scans the filter voltage in the blocking mode so as to pass outside a stable region, wherein the stable region refers to a set of combinations of a high frequency voltage and a direct current voltage in which ions can pass through the filter portion and reach the detector.

8. A program recording medium, characterized in that: A program recording medium having recorded thereon a program for a quadrupole mass spectrometer, the quadrupole mass spectrometer comprising: an ion source, which ionizes the sample; A filter unit having a quadrupole and separating the masses of ions generated in the ion source; as well as a detector for detecting ions that have passed through the filter portion, The program recording medium causes the computer to function as a filter voltage controller, a baseline calculation unit, and an analysis unit. The filter voltage controller controls the filter voltage composed of a high-frequency voltage and a direct current voltage applied to the quadrupole, and switches between a blocking mode and an incident mode, wherein the blocking mode prevents the ions incident on the filter section from being incident on the detector, and the incident mode allows the ions incident on the filter section to be incident on the detector, The baseline calculation unit calculates a baseline based on the output of the detector in the blocking mode, the analyzing unit outputting an analysis result of the sample based on the output of the detector in the incident mode and the baseline calculated by the baseline calculating unit, The filter voltage controller functions to scan the filter voltage in the blocking mode so as to pass outside a stable region, wherein the stable region refers to a set of combinations of a high frequency voltage and a direct current voltage that allow ions to pass through the filter portion and reach the detector.

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