JP2018032481A - Mass spectroscope and software for mass spectroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mass spectrometer having a long filament life. A mass spectrometer according to the present invention is a mass spectrometer that ionizes a sample using thermions, and corresponds to a filament 212 that generates thermions and the magnitude of power supplied to the filament 212. The parameter detection unit 311 that detects the value of the parameter that changes, and the parameter detection unit 311 issues a predetermined warning when the parameter detection unit 311 detects the value of the parameter indicating that the power exceeds the predetermined value. It includes 312. This allows the user to recognize that the amount of power supplied to the filament is large, and motivates the user to set the power appropriately, such as performing an operation to reduce the amount of power supplied if unnecessary. Can be given to the user. [Selection diagram] Fig. 2

Description

  The present invention relates to a mass spectrometer and software for a mass spectrometer, and more particularly to a mass spectrometer that directly ionizes a sample with thermal electrons or generates buffer ions with thermal electrons, thereby ionizing the sample, and software used therefor. .

  In the chromatograph mass spectrometer, the components of the sample are temporally separated by the column of the chromatograph part and introduced into the mass analyzer, and the mass spectrum is sequentially obtained after the sample is ionized by the mass analyzer. One method for ionizing a sample in the mass spectrometer is an electron ionization (EI) method. In the electron ionization method, in general, thermoelectrons are generated by heating a filament, and the thermoelectrons are accelerated by an acceleration voltage and collided with a molecule of a sample to ionize the molecule (see, for example, Patent Document 1). A chemical ionization (CI) method is also often used in which buffer ions are generated by thermoelectrons and the sample is ionized by colliding the buffer ions with a sample gas.

  In these mass spectrometers, the greater the amount of thermoelectrons generated per unit time, the greater the amount of ions that are generated, enabling highly sensitive detection. In order to increase the amount of thermoelectrons generated per unit time, the power supplied to the filament may be increased. On the other hand, if the electric power supplied to the filament is continued to be used while being increased, the life of the filament is shortened. Therefore, in these mass spectrometers, in general, the user can set the detection sensitivity (for example, select from several stages between the high sensitivity mode and the high concentration (low sensitivity) mode). Thus, the user can make a setting to increase the power supplied to the filament when high-sensitivity detection is necessary, and to suppress the power when detection with high sensitivity is unnecessary.

JP 2007-227255 A

  Thus, although the power supplied to the filament can be adjusted by the setting performed by the user, the user tends to select to perform highly sensitive detection without being aware of the life of the filament. Therefore, a state with higher sensitivity than necessary, that is, a state where the power supplied to the filament is larger than necessary, becomes a normal state, and there is a possibility that the life of the filament is unnecessarily shortened.

  The problem to be solved by the present invention is to provide a mass spectrometer having a longer filament life and software for the mass spectrometer.

The present invention made to solve the above problems is a mass spectrometer that ionizes a sample using thermoelectrons,
a) a filament that generates thermoelectrons;
b) a parameter detection unit that detects a value of a parameter that changes in accordance with the magnitude of power supplied to the filament;
c) The parameter detection unit includes a warning processing unit that issues a predetermined warning when a parameter value indicating that the electric power exceeds a predetermined value is detected.

  According to the mass spectrometer of the present invention, when the power supplied to the filament exceeds a predetermined value, the parameter detection unit detects a parameter indicating that, and the warning processing unit issues a predetermined warning. This makes it possible for the user to recognize that the amount of power supplied to the filament is large, and to motivate the power to be set appropriately, such as by performing an operation to reduce the amount of power supplied if unnecessary. Can be given to the user.

  The parameter may be a current or voltage supplied to the filament. Further, the flow of thermoelectrons generated in the ion source by the thermoelectrons emitted from the filament (thermoelectron flow) can also be used as the parameter because it changes in accordance with the magnitude of power supplied to the filament. . Conventionally, an ion source using a filament measures the thermionic current in that it directly represents the ionization efficiency of the sample because it acts directly on the sample, not the power supplied to the filament. (Refer to the background art section of Patent Document 1), it is preferable to use a thermionic current as the parameter. Furthermore, the intensity of light (infrared rays) emitted from the filament may be detected and used as the parameter. Alternatively, when the detection sensitivity set by the user directly corresponds to the power of the filament, the setting of the detection sensitivity may be used as the parameter.

  As a warning issued by the warning processing unit, a warning image that displays a predetermined image on a display screen, a warning light, a sound, or the like can be used. However, even if the power supplied to the filament exceeds the predetermined value and a warning is issued, if the detection sensitivity needs to be increased, the analysis must be continued, so the warning continues to be issued. However, it is desirable not to put a large psychological burden on the user. In this regard, it is preferable that the warning issued by the warning processing unit displays a predetermined image on the display screen.

  The mass spectrometer software according to the present invention is software that causes a computer to execute processing in the warning processing unit of the mass spectrometer.

  According to the mass spectrometer and the mass spectrometer software according to the present invention, the warning processing unit issues a predetermined warning when the power supplied to the filament exceeds a predetermined value, so that the user supplies the filament to the filament. Contributes to setting the power to be appropriately set. Thereby, the lifetime of the filament is not unnecessarily shortened, and the filament can be used for a longer time.

The figure which shows the whole schematic structure about one Embodiment of the mass spectrometer which concerns on this invention. The figure which shows the detail of a structure of the ion source which the mass spectrometer of this embodiment has. The figure which shows an example of the whole screen displayed on the display part in the mass spectrometer of this embodiment. In the filament replacement time display window in the display unit of the mass spectrometer of the present embodiment, a warning (a) indicating that the power supplied to the filament exceeds the predetermined value is not displayed and a warning is displayed. The figure which shows the state (b) which exists. The figure which shows the modification of a structure of the ion source which the mass spectrometer of this embodiment has.

  An embodiment of the mass spectrometer and the software for the mass spectrometer according to the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram showing an overall configuration of a gas chromatograph mass spectrometer 1 which is an embodiment of a mass spectrometer according to the present invention. The gas chromatograph mass spectrometer 1 includes a gas chromatograph part (GC part) 10 and a mass spectrometer part (MS part) 20. The GC unit 10 includes an injector 11 that introduces a sample and a column 12 that separates components of the sample introduced by the injector 11.

  The MS unit 20 includes an ion source 21 that ionizes the molecules of the sample that has passed through the column 12, an ion lens 22 that focuses ions ionized by the ion source 21, and a mass that is determined by the applied voltage by controlling the applied voltage. A quadrupole filter 23 that passes only ions having a charge ratio m / z and a detector 24 that detects the ions that have passed through the quadrupole filter 23 are provided. The entire MS unit 20 is accommodated in a vacuum vessel 25, and the vacuum vessel 25 is kept in a vacuum by a vacuum pump 26.

  Furthermore, the gas chromatograph mass spectrometer 1 includes a control unit 31 that controls the operation of each unit, an input unit 32 through which a user inputs various analysis conditions including a set value (detection sensitivity) of a thermoelectron current described below, and a later-described unit. A display unit 33 for displaying various types of information including the warning image is provided. The control unit 31, the input unit 32, and the display unit 33 are realized by hardware and software of a personal computer (PC) 30. The function of the control unit 31 and the information displayed on the display unit 33 will be described in detail later.

  Next, the configuration of the ion source 21 will be described. As shown in FIG. 2, the ion source 21 has an ionization chamber 211. The walls of the ionization chamber 211 are made of a conductive material and are grounded. In the ionization chamber 211, a sample molecule introduction port 2111 for introducing sample molecules that have passed through the column 12, an ion extraction port 2112 for extracting ions in which the sample molecules are ionized, and a thermoelectron introduction port 2113 for introducing thermoelectrons. And a thermoelectron outlet 2114 for delivering thermoelectrons. The above-described ion lens 22 is provided outside the ion extraction port 2112 (not shown in FIG. 2). Electrons in the ionization chamber 211 are moved toward the ion lens 22 due to a potential difference between the ion lens 22 and the ionization chamber 211. Pulled out.

  In addition, the ion source 21 includes a filament 212 that generates thermoelectrons disposed outside the thermoelectron introduction port 2113. A filament power supply 213 that applies a voltage to the filament 212 and that can change the voltage is connected to the filament 212. The voltage of the filament power supply 213 is controlled by the control unit 31. A thermoelectron accelerating power source 214 is connected between the filament 212 and the wall of the ionization chamber 211 (that is, ground) to apply a potential difference between the filament 212 and the negative side of the filament 212.

  Further, the ion source 21 has a thermoelectron collector 215 arranged outside the thermoelectron outlet 2114. The thermoelectron collector 215 collects thermoelectrons generated by the filament 212 and passed through the ionization chamber 211. On the wall (ground) of the thermoelectron collector 215 and the ionization chamber 211, a collector power source 216 that applies a potential difference between the thermoelectron collector 215 and the thermoelectron collector 215 side flows between the filament 212 and the thermoelectron collector 215 ( A thermoelectron ammeter 217 is provided for measuring the value of current (hereinafter referred to as “thermoelectron current”) due to thermoelectrons (collected by the thermoelectron collector 215). The thermoelectron ammeter 217 is a normal ammeter, and is connected to the control unit 31 so as to transmit its output value, that is, the value of the thermoelectron current to the control unit 31.

  The control unit 31 has a function of performing various processes of the gas chromatograph mass spectrometer 1. Here, in the present invention, a warning is issued when the power supplied to the filament 212 exceeds a predetermined value. The configuration of the parameter detection unit 311 and the warning processing unit 312 will be described. The parameter detection unit 311 receives the value of the thermionic current that is the output value from the thermionic ammeter 217. The warning processing unit 312 determines whether or not the value of the thermoelectron current received by the parameter detection unit 311 exceeds a predetermined value. When the value exceeds the predetermined value, a warning display to be described later is displayed on the display unit 33. A signal to be transmitted is transmitted to the display unit 33.

  FIG. 3 shows an example of information displayed on the display unit 33. In this example, a chromatogram display area 331, a mass spectrum display area 332, an analysis condition display / input area 333, and an apparatus monitor area 334 are displayed on the screen of the display unit 33. The chromatogram displayed in the chromatogram display area 331 and the mass spectrum displayed in the mass spectrum display area 332 are updated as needed during analysis. The analysis condition display / input area 333 displays the analysis conditions including the set value of the thermoelectron current that affects the power supplied to the filament 212, and allows the analysis conditions to be input using the input unit 32. It has become. The analysis conditions can be input by reading a file (method file) in which the analysis conditions are recorded in addition to the method of directly inputting to the analysis condition display / input area 333. In this case, the contents of the read method file are displayed in the analysis condition display / input area 333.

  In the apparatus monitor area 334, the operation status (gas flow rate, temperature and vacuum degree of each part, ionization mode (“EI”, “CI”, etc.)) of each part in the gas chromatograph mass spectrometer 1 is displayed. Further, in the device monitor area 334, a consumable information display unit 335 (“GC consumables” column and “MS consumables” in the drawing) that notifies the replacement timing of consumables used in the GC unit 10 and the MS unit 20 is displayed. Column) is provided. In “GC Consumables”, “Septum” and “Glass Insert”, and in “MS Consumables”, “Filament”, “Ion Source”, and “Detector” are targeted for notification of replacement time, and display consumable information In the part 335, one display window is provided for each consumable. The replacement time of the consumables is managed for each consumable based on the operation time of the apparatus, and the color of the background of the display window of the consumables information display unit 335 is darker as the replacement time is approached.

  In the present embodiment, when a signal for displaying a warning is input from the warning processing unit 312 to the display unit 33, a warning is displayed on the filament replacement time display window 3351 in the consumable information display unit 335 as follows. Is made. In a state where the warning is not displayed, the filament replacement time display window 3351 displays a black symbol with a filament designed (FIG. 4A), but the warning is displayed. In the state, the filament replacement time display window 3351 displays a red upward arrow in addition to the black symbol (FIG. 4B). In any case, the background is displayed in a color indicating the proximity of the filament replacement time determined based on the operating time of the apparatus as described above.

  The operation of the gas chromatograph mass spectrometer 1 of the present embodiment will be described focusing on the points related to the present invention. First, the analysis condition is set when the user inputs the analysis condition in the analysis condition display / input area 333 or reads the method file. At that time, one of the input analysis conditions is a set value of the thermionic current. The larger the set value, the higher the probability that the sample molecule and the thermoelectrons collide in the ion source 21 and the more ions are generated, so that the detection sensitivity increases, while more power is supplied to the filament 212. Since the necessity arises, the lifetime of the filament 212 is shortened.

  When analysis is started according to the input analysis conditions, a sample is introduced from the injector 11, and the sample is separated into components while passing through the column 12. The molecules constituting the sample reach the ion source 21 with different holding times for each component, and are introduced into the ionization chamber 211 from the sample molecule introduction port 2111.

  In the ion source 21, power is supplied from the filament power source 213 to the filament 212, so that thermoelectrons are emitted from the filament 212. The thermoelectrons are accelerated by an acceleration voltage applied between the filament 212 and the wall of the ionization chamber 211 by the thermoelectron acceleration power source 214 and introduced into the ionization chamber 211 from the thermoelectron inlet 2113. In the ionization chamber 211, some of the thermoelectrons collide with the sample molecules, and the molecules are ionized.

  The ions thus generated are converged by the ion lens 22, and only ions having a predetermined mass-to-charge ratio m / z determined by the voltage applied to the quadrupole filter 23 pass through the quadrupole filter 23 and are detected. 24. Since the operations of the ion lens 22, the quadrupole filter 23, and the detector 24 are the same as those of a normal gas chromatograph mass spectrometer, detailed description thereof is omitted.

  Thermoelectrons in the ionization chamber 211 are sent out of the ionization chamber 211 through a thermoelectron outlet 2114. The transmitted thermoelectrons are captured by the thermoelectron collector 215 due to the potential difference between the thermoelectron collector 215 provided by the collector power source 216 and the wall of the ionization chamber 211, and a thermoelectron current value is output from the thermoelectron ammeter 217. Is done.

  Based on the value of the thermoelectron current output from the thermoelectron ammeter 217, the control unit 31 feedback-controls the output voltage of the thermoelectron acceleration power supply 214 so that the thermoelectron current approaches a value set by the user. . This feedback control is necessary because the thermionic current varies depending on the concentration of molecules in the ionization chamber 211. Therefore, even if the thermoelectron current is the same value, the power supplied to the filament will differ somewhat depending on the concentration of molecules, but the difference is the thermoelectron current as an indicator of the magnitude of power supplied to the filament. It is not so big as to cause trouble.

  Along with the feedback control by the control unit 31, the parameter detection unit 311 of the control unit 31 receives the value of the thermoelectron current and transmits it to the warning processing unit 312. The warning processing unit 312 determines whether or not the value of the thermoelectron current exceeds a predetermined value, and if it exceeds the predetermined value, transmits a warning display signal to the display unit 33. The filament replacement time display window 3351 displayed on the display unit 33 receives the signal from the warning processing unit 312 and displays the warning shown in FIG. As the electric power supplied to the filament 212 increases, the thermoelectron current also increases. Therefore, by setting the predetermined value of the thermoelectron current corresponding to the electric power supplied to the filament 212 for which a warning is to be displayed, an appropriate value can be obtained. A warning can be issued under certain conditions.

  By displaying such a warning, a user who sees the warning display can recognize that the amount of power supplied to the filament 212 is large. And if unnecessary, it is possible to give the user the motivation to appropriately set the power, such as performing an operation for reducing the amount of power supply. On the other hand, if it is necessary to detect ions with high sensitivity, the analysis may be continued regardless of the warning display.

The present invention is not limited to the above embodiment.
For example, in the above embodiment, the value of the thermoelectron current measured by the thermoelectron ammeter 217 is used as a parameter that changes corresponding to the power supplied to the filament 212. The parameter may be used. In the ion source 21 </ b> A shown in FIG. 5, the value of the filament current flowing through the filament 212 is obtained by using a filament ammeter 218 composed of a normal ammeter. The output of the filament ammeter 218 is input to the parameter detection unit 311. If the value exceeds a predetermined value, the warning processing unit 312 performs warning processing similar to the above. The ion source 21A is also provided with a thermoelectron ammeter 217 for feedback control of the thermoelectron current. As described above, the ion source 21A needs to use an ammeter (filament ammeter 218) more than the above-described ion source 21, but based on the filament current, which is a parameter closer to the power supplied to the filament 212, Appropriate warnings can be made.

  In the above embodiment, the user inputs the set value of the thermionic current. Instead, the detection sensitivity is input by a numerical value in several steps (direct input of the numerical value, selection by pull-down, setting by moving the slide bar, etc. ). In that case, the value of the thermoelectron current or filament current is set according to the value of the detection sensitivity.

  Alternatively, the value of power supplied to the filament 212 by the user may be directly input, and the value may be used as the parameter.

  The warning display shown in FIG. 4 is an example. For example, the arrow may blink so that the upward arrow in FIG. 4 (b) is more conspicuous. You may display the character (sentence) to show. Alternatively, a sound or light may be emitted as a warning.

Furthermore, although the gas chromatograph mass spectrometer was described as an example in the above embodiment, the present invention can be applied to any mass spectrometer having an ion source using a similar filament.
In addition, the present invention can be variously modified from the above-described embodiment along the gist thereof.

DESCRIPTION OF SYMBOLS 1 ... Gas chromatograph mass spectrometer 10 ... GC part 11 ... Injector 12 ... Column 20 ... MS part 21, 21A ... Ion source 211 ... Ionization chamber 2111 ... Sample molecule introduction port 2112 ... Ion extraction port 2113 ... Thermal electron introduction port 2114 ... Thermoelectron outlet 212 ... Filament 213 ... Filament power supply 214 ... Thermoelectron acceleration power supply 215 ... Thermoelectron collector 216 ... Collector power supply 217 ... Thermoelectron ammeter 218 ... Filament ammeter 22 ... Ion lens 23 ... Quadrupole filter 24 ... Detection Apparatus 25 ... Vacuum container 26 ... Vacuum pump 31 ... Control unit 311 ... Parameter detection unit 312 ... Warning processing unit 32 ... Input unit 33 ... Display unit 331 ... Chromatogram display region 332 ... Mass spectrum display region 333 ... Analysis condition display / input Area 334 ... Device monitor area 335 ... Consumables information table Part 3351 ... filament replacement time display window

Claims (4)

A mass spectrometer that ionizes a sample using thermal electrons,
a) a filament that generates thermoelectrons;
b) a parameter detection unit that detects a value of a parameter that changes in accordance with the magnitude of power supplied to the filament;
c) The mass spectrometer includes a warning processing unit that issues a predetermined warning when the parameter detection unit detects a parameter value indicating that the electric power exceeds a predetermined value.   The mass spectrometer according to claim 1, wherein the parameter detection unit detects a thermal electron flow generated in the ion source as the parameter.   The mass spectrometer according to claim 1, wherein the warning processing unit displays a predetermined image on the display screen as the warning.   Software for a mass spectrometer that causes a computer to execute processing in the warning processing unit of the mass spectrometer according to any one of claims 1 to 3.

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