JP2015118011A - Gas chromatograph - Google Patents

Abstract

A gas chromatograph capable of reducing the amount of carrier gas used is provided.
The state of gas introduction into the column during the analysis of the sample is changed to the carrier gas introduction state (step S102), and the component to be measured is detected by the detector (Yes in step S103), and then the column is analyzed during the analysis. Switch to the protective gas introduction state (step S104). Thereby, even if it is in the middle of performing analysis in the carrier gas introduction state, after the measurement target component in the sample is detected by the detector, the analysis can be performed by switching to the column protection gas introduction state. Therefore, not only during standby but also during periods when it is not necessary to use carrier gas during analysis, column protection gas can be introduced into the column instead of carrier gas, reducing the amount of carrier gas used Can do.
[Selection] Figure 3

Description

  The present invention relates to a gas chromatograph for introducing a sample into a column together with a carrier gas and detecting a measurement target component in the sample separated in the column with a detector.

  A gas chromatograph mass spectrometer (GC / MS), which is an example of a gas chromatograph, includes a gas chromatograph section and a mass spectrometer section. The sample supplied to the column of the gas chromatograph unit together with the carrier gas is separated for each sample component in the process of passing through the column, and sequentially guided to the vacuum mass analysis unit for mass analysis.

  In this type of apparatus, when the apparatus is turned off after the analysis is completed, it takes time until the mass spectrometer is evacuated even if the apparatus is turned on during the next analysis. For this reason, in many cases, after the analysis is completed, even if there is a time until the next analysis is performed, the apparatus is kept in a standby state with the apparatus powered on.

  However, when the apparatus is turned on and the carrier gas is allowed to flow for a long time without flowing, the column may be deteriorated due to the high temperature of the ion source of the mass spectrometer. Therefore, during standby, in order to protect the column, a column protective gas may be circulated in the column (see, for example, Patent Document 1 below).

As the carrier gas, for example, He gas is used. On the other hand, as the column protective gas, for example, N ₂ gas is used as a gas cheaper than the carrier gas. In order to reduce the running cost, it is preferable to use a less expensive column protective gas while minimizing the amount of carrier gas used.

JP 2013-44647 A

  In the conventional configuration, when the apparatus shifts from the analysis mode to the standby mode, the gas introduced into the column is switched from the carrier gas to the column protective gas. However, after the measurement target component in the sample is detected, it may not be necessary to introduce the carrier gas into the column even in the analysis mode.

  That is, since this type of apparatus performs analysis based on a method file including a plurality of types of analysis conditions, even if a measurement target component is detected during the analysis, it is preliminarily set as one of the analysis conditions. The analysis is continued until the set analysis time elapses. In such a case, since the carrier gas is used more than necessary, the running cost becomes high.

  This invention is made | formed in view of the said situation, and it aims at providing the gas chromatograph which can reduce the usage-amount of carrier gas.

  A gas chromatograph according to the present invention is a gas chromatograph for introducing a sample into a column together with a carrier gas, and detecting a measurement target component in the sample separated in the column with a detector, comprising a carrier gas supply unit, A column protective gas supply unit and a gas switching unit are provided. The carrier gas supply unit supplies a carrier gas. The column protective gas supply unit supplies a column protective gas for protecting the column. The gas switching unit is either a carrier gas introduction state in which a carrier gas is introduced into the column from the carrier gas supply unit, or a column protection gas introduction state in which a column protection gas is introduced into the column from the column protection gas supply unit. In addition, the state of gas introduction into the column is switched. The gas switching unit sets the introduction state of the gas to the column during the analysis of the sample as the carrier gas introduction state, and after the component to be measured is detected by the detector, the column protective gas introduction state during the analysis. Switch to.

  According to such a configuration, even when the analysis is being performed with the carrier gas introduced, after the measurement target component in the sample is detected by the detector, the analysis is performed by switching to the column protective gas introduced state. It can be carried out. Therefore, not only during standby but also during periods when it is not necessary to use carrier gas during analysis, column protection gas can be introduced into the column instead of carrier gas, reducing the amount of carrier gas used Can do.

  The gas chromatograph may further include a gas flow rate control unit. The gas flow rate control unit switches the flow rate of the gas flowing in the column according to the type of gas when the carrier gas introduction state is switched to the column protective gas introduction state during the analysis.

  According to such a configuration, even when the carrier gas introduction state is switched to the column protection gas introduction state during the analysis, the column protection gas can be introduced into the column at a flow rate corresponding to the type of gas. When the analysis is performed based on the method file, the carrier gas is introduced into the column at a predetermined flow rate according to the type of the carrier gas during the analysis, but when the column protective gas introduction state is switched, Even during the analysis, it is possible to switch to a gas flow rate suitable for the type of column protective gas. Therefore, it is possible to perform a good analysis while reducing the amount of carrier gas used.

  The gas chromatograph may further include an analysis condition determination unit and an error notification unit. The analysis condition determination unit determines whether or not a predetermined analysis condition is satisfied when the sample is analyzed in a column protective gas introduction state before starting the analysis of the sample. The error notification unit notifies an error when the analysis condition determination unit determines that the predetermined analysis condition is not satisfied.

  According to such a configuration, assuming that the carrier gas introduction state is switched to the column protective gas introduction state during the analysis and it is determined that the predetermined analysis condition is not satisfied, an error is given to the operator. Can be notified. Accordingly, it is possible to prevent in advance a situation in which analysis cannot be performed satisfactorily by switching from the carrier gas introduction state to the column protective gas introduction state during the analysis.

  By the way, the background of trying to reduce the usage amount of the carrier gas as described above is that the He gas generally used as the carrier gas is not only expensive, but the He gas may be exhausted in the future. There are also circumstances such as. In order to further reduce the amount of He gas used, it is conceivable that the entire analysis is performed with a gas other than the He gas, instead of switching the He gas to another gas during the analysis as described above.

  However, although an auto-tuning method using He gas has been established as an auto-tuning method performed in advance before analysis in a gas chromatograph mass spectrometer, an auto-tuning method using a gas other than He gas is The current situation is not established. Therefore, when an analysis is performed using a gas other than the He gas, there is a possibility that accurate tuning cannot be performed even if auto-tuning is performed using that gas. From such a background, there is a demand for a gas chromatograph mass spectrometer capable of accurately performing auto-tuning even when performing analysis using a gas other than He gas.

  A gas chromatograph mass spectrometer for solving such problems guides a measurement target component in a sample separated by a column to a mass analysis unit, and performs mass spectrometry by ionizing the measurement target component in the mass analysis unit. A gas chromatograph mass spectrometer for performing, comprising: a first gas supply unit, a second gas supply unit, a gas switching unit, an auto-tuning processing unit, and an analysis processing unit. The first gas supply unit supplies He gas. The second gas supply unit supplies a gas other than He gas. The gas switching unit is a first gas introduction state where He gas is introduced into the column from the first gas supply unit, or a second gas which introduces gas other than He gas from the second gas supply unit into the column. The gas introduction state to the column is switched to one of the introduction states. The auto tuning processing unit performs auto tuning based on the detected intensity of the standard sample detected by the mass analyzing unit. The analysis processing unit performs analysis based on the detection intensity of the target sample detected by the mass analysis unit. The gas switching unit is in the first gas introduction state during auto-tuning and in the second gas introduction state during analysis.

  According to such a configuration, analysis can be performed using a gas other than He gas, so that the amount of He gas used can be reduced. Moreover, since auto-tuning can be performed using the He gas for which the method is established, it can tune correctly. Therefore, even when analysis is performed using a gas other than He gas, auto-tuning can be performed accurately.

  The gas switching unit may switch from the second gas introduction state to the first gas introduction state at the start of auto tuning, and switch from the first gas introduction state to the second gas introduction state at the end of auto tuning.

  According to such a configuration, He gas can be introduced into the column only during auto tuning, and gas other than He gas can be introduced into the column at times other than auto tuning. Thereby, the usage-amount of He gas can be suppressed to the minimum necessary.

  The auto-tuning processing unit starts auto-tuning when a detected intensity in a mass-to-charge ratio corresponding to a gas other than He gas supplied from the second gas supply unit becomes a predetermined first threshold value or less. May be.

  According to such a configuration, auto-tuning using He gas can be started in a state where gases other than He gas are sufficiently removed from the column. Therefore, since gas other than He gas can be prevented from affecting the result of auto tuning, auto tuning can be performed more accurately.

  The analysis processing unit may start the analysis when the detection intensity at the mass-to-charge ratio corresponding to the He gas supplied from the first gas supply unit is equal to or lower than a predetermined second threshold value.

  According to such a configuration, the analysis using a gas other than the He gas can be started in a state where the He gas is sufficiently removed from the column. Therefore, since He gas can be prevented from affecting the result of analysis, analysis can be performed more accurately.

  According to the present invention, since the column protective gas can be introduced into the column instead of the carrier gas during the period when the carrier gas does not need to be used during the analysis, the amount of the carrier gas used can be reduced. .

It is the schematic which showed the structural example of the gas chromatograph which concerns on one Embodiment of this invention. It is the block diagram which showed an example of the electrical constitution in the gas chromatograph of FIG. It is the flowchart which showed an example of the process by the control part at the time of switching the introduction state of the gas to a column during analysis. It is the flowchart which showed an example of the process by the control part at the time of performing error alerting | reporting before the analysis start. It is the block diagram which showed an example of the electrical constitution of the gas chromatograph which concerns on another embodiment. It is the flowchart which showed an example of the process by the control part at the time of auto tuning. It is the flowchart which showed an example of the process by the control part at the time of analysis.

  FIG. 1 is a schematic diagram showing a configuration example of a gas chromatograph according to an embodiment of the present invention. This gas chromatograph is a gas chromatograph mass spectrometer (GC / MS) provided with a gas chromatograph part (GC part 1) and a mass spectrometer part (MS part 2).

  The GC unit 1 includes, for example, a column 11, a sample vaporizing chamber 12, a column oven 13, an AFC (Auto Flow Controller) 14, a first gas supply path 15, a second gas supply path 16, and open / close valves 17 and 18. Yes. The column 11 is composed of, for example, a capillary column, and has an upstream end connected to the sample vaporizing chamber 12 and a downstream end connected to the MS unit 2.

  The column 11 is accommodated in a column oven 13 together with a heater and a fan (both not shown). The column oven 13 is for heating the column 11, and at the time of analysis, a constant temperature analysis for performing analysis while maintaining the temperature in the column oven 13 constant by driving a heater and a fan as appropriate, or a column oven A temperature rising analysis for performing analysis while gradually increasing the temperature in the chamber 13 can be executed.

  A carrier gas or a column protective gas can be selectively supplied to the column 11 via the AFC 14. The AFC 14 is connected to a first gas supply path 15 in which an opening / closing valve 17 is interposed and a second gas supply path 16 in which an opening / closing valve 18 is interposed. The first gas supply path 15 constitutes a carrier gas supply unit for supplying a carrier gas to the column 11. Further, the second gas supply path 16 constitutes a column protective gas supply unit for supplying column protective gas to the column 11.

  Accordingly, the carrier gas can be supplied to the AFC 14 by opening the opening / closing valve 17, and the column protective gas can be supplied to the AFC 14 by opening the opening / closing valve 18. The AFC 14 is for adjusting the gas flow rate. When the opening / closing valve 17 is opened, the AFC 14 can adjust the flow rate of the carrier gas flowing through the column 11, and when the opening / closing valve 18 is opened, the column The flow rate of the column protective gas flowing through the inside 11 can be adjusted.

  As the carrier gas, for example, He gas is used. At the time of analysis, the carrier gas is supplied to the sample vaporizing chamber 12 by opening the opening / closing valve 17, and the sample vaporized in the sample vaporizing chamber 12 is introduced into the column 11 together with the carrier gas. In the GC unit 1, each sample component is separated while the carrier gas passes through the column 11, and is sequentially guided to the MS unit 2 as a detector.

  The MS unit 2 is provided with a vacuum chamber, an ion detector, and the like (both not shown). During the analysis, each sample component separated by the column 11 is introduced into a vacuum chamber in a vacuum state. And mass spectrometry can be performed by detecting each sample component ionized within a vacuum chamber with an ion detector.

The column protective gas is a gas for protecting the column 11, and for example, N ₂ gas is used. In the present embodiment, the column protective gas is introduced into the column 11 by opening the on-off valve 18 after the measurement target component at the time of analysis is detected by the MS unit 2 in addition to the standby time other than the time of analysis. It is like that. By introducing the column protective gas into the column 11, it is possible to prevent the column 11 from deteriorating due to the ion source of the MS unit 2 becoming high temperature.

The column protective gas is not limited to N ₂ gas, but is preferably a gas that is less expensive than the carrier gas. That is, as the carrier gas and the column protective gas, various other gases can be used as long as the column protective gas is a cheaper combination. By using the column protective gas, the amount of carrier gas used can be reduced, and the column 11 can be protected using a cheaper column protective gas, so that the running cost can be reduced.

  FIG. 2 is a block diagram showing an example of an electrical configuration in the gas chromatograph of FIG. The operation of this gas chromatograph is controlled by a control unit 3 including, for example, a CPU (Central Processing Unit).

  The control unit 3 functions as a column switching control unit 31, a gas flow rate control unit 32, an analysis condition determination unit 33, an error notification unit 34, and the like when the CPU executes a program. The gas chromatograph includes a storage unit 4 and a display unit 5 in addition to the control unit 3. The storage unit 4 can be configured by, for example, a hard disk or a RAM (Random Access Memory). The display unit 5 can be configured by a liquid crystal display, for example.

  The column switching control unit 31 performs control for switching the gas introduction state to the column 11 by switching the open / close state of the open / close valves 17 and 18. The column switching control unit 31 constitutes a gas switching unit together with the open / close valves 17 and 18. When the opening / closing valve 17 is opened and the opening / closing valve 18 is closed by the column switching control unit 31, the carrier gas is introduced into the column 11 from the first gas supply path 15. On the other hand, when the opening / closing valve 18 is opened and the opening / closing valve 17 is closed by the column switching control unit 31, the column protection gas introduction state in which the column protection gas is introduced into the column 11 from the second gas supply path 16 is established.

  During sample analysis, the state of gas introduction into the column 11 is set to the carrier gas introduction state. Also, when auto-tuning is performed by introducing a standard sample into the column 11, the state of gas introduction into the column 11 is the carrier gas introduction state. However, the amount of the carrier gas used is reduced by setting the column protective gas introduction state during the standby period during analysis or auto tuning.

  Furthermore, when the measurement target component in the sample is detected by the MS unit 2 during the analysis, the analysis is performed after switching to the column protective gas introduction state even during the analysis. Therefore, the column protective gas can be introduced into the column 11 in place of the carrier gas not only during standby but also during a period when the carrier gas is not required during analysis, so that the amount of carrier gas used is reduced. be able to.

  The gas flow rate control unit 32 controls the flow rate of the gas flowing through the column 11 by controlling the AFC 14. That is, in the carrier gas introduction state, the flow rate of the carrier gas flowing through the column 11 can be controlled by the gas flow rate control unit 32, and in the column protection gas introduction state, the column flow rate flowing through the column 11 by the gas flow rate control unit 32 is protected. The gas flow rate can be controlled. The flow rate of the gas flowing in the column 11 is not limited to the configuration controlled by the AFC 14, but may be configured to be performed by gas pressure control using an APC (Auto Pressure Controller), for example, It may be configured to be performed by linear velocity control.

  The gas flow rate control unit 32 controls the gas flow rate based on the method file stored in the storage unit 4. The method file includes a plurality of types of analysis conditions necessary for the analysis, such as the flow rate of the carrier gas and the temperature of the column 11. In this example, a batch file in which a plurality of method files are arranged in a predetermined order is executed, whereby analysis is sequentially performed for each method file.

In the present embodiment, when the carrier gas introduction state is switched to the column protective gas introduction state during the analysis, the gas flow rate control unit 32 switches the flow rate of the gas flowing in the column 11 according to the type of gas. It is like that. For example, when He gas is introduced into the column 11 as the carrier gas and when N ₂ gas is introduced into the column 11 as the column protective gas, there is a flow rate suitable for the type of those gases, If the gas flow rate is not adjusted, there is a possibility that problems such as errors occur and the column 11 is not sufficiently protected.

  When the analysis is performed based on the method file, the carrier gas is introduced into the column 11 at a flow rate set in advance according to the type of the carrier gas during the analysis. In this embodiment, the column protective gas is switched to the introduction state. In such a case, it is possible to switch to a gas flow rate suitable for the type of column protective gas even during analysis. Therefore, it is possible to perform a good analysis while reducing the amount of carrier gas used.

  The analysis condition determination unit 33 determines whether or not a predetermined analysis condition is satisfied when the sample is analyzed in the column protective gas introduction state before starting the analysis of the sample. For example, when a sample is analyzed in a column protective gas introduction state, if a predetermined gas flow rate cannot be obtained, it is determined that a predetermined analysis condition is not satisfied. Such a determination can be made by calculating each parameter value when an analysis is performed using each type of gas based on the method file stored in the storage unit 4.

  When the analysis condition determination unit 33 determines that the predetermined analysis condition is not satisfied, the error notification unit 34 notifies the error by displaying the fact on the display unit 5. That is, assuming that the carrier gas introduction state is switched to the column protective gas introduction state during the analysis and it is determined that the predetermined analysis condition is not satisfied, an error can be notified to the operator. Accordingly, it is possible to prevent in advance a situation in which the analysis cannot be performed satisfactorily by switching from the carrier gas introduction state to the column protective gas introduction state during the analysis.

  FIG. 3 is a flowchart illustrating an example of processing performed by the control unit 3 when the state of gas introduction into the column 11 is switched during analysis. Before the analysis is started, the column protective gas is introduced into the column 11, but when the analysis is started (Yes in step S101), the column protective gas introduction state is switched to the carrier gas introduction state. Thus, the carrier gas is introduced into the column 11 (step S102).

  During the analysis, the carrier gas introduction state is maintained until the measurement target component in the sample is detected by the MS unit 2. When the measurement target component in the sample is detected by the MS unit 2 (Yes in step S103), the column protective gas is introduced into the column 11 by switching from the carrier gas introduction state to the column protection gas introduction state. (Step S104). At this time, the flow rate of the gas flowing through the column 11 is switched according to the type of gas used as the column protective gas (step S105).

  In the present embodiment, a configuration has been described in which the measurement target component in the sample is detected by the MS unit 2 and the carrier gas introduction state is switched to the column protective gas introduction state during the analysis. However, the configuration is not limited to such a configuration. For example, based on the fact that a predetermined time has elapsed as the time until the measurement target component in the sample is detected by the MS unit 2, the carrier gas introduction state during the analysis The configuration may be such that the column protection gas introduction state is switched to the column protection gas introduction state.

  FIG. 4 is a flowchart showing an example of processing by the control unit 3 when performing error notification before starting analysis. In the present embodiment, a method file is read from the storage unit 4 before the analysis is started (step S201), and a predetermined analysis is performed when a sample is analyzed in a column protective gas introduction state based on the method file. It is determined whether or not the condition is satisfied (step S202).

  As a result, when it is determined that the analysis condition is satisfied (Yes in step S203), the analysis is started as it is. On the other hand, when it is determined that the analysis condition is not satisfied (No in step S203), an error is notified by displaying the fact on the display unit 5 (step S204).

  In the present embodiment, the configuration in which the error notification by the error notification unit 34 is performed by display on the display unit 5 has been described. However, the configuration is not limited to such a configuration, and the configuration may be such that the error notification unit 34 notifies the error by other modes such as voice.

  Further, in the present embodiment, the configuration in which the measurement target component in the sample separated in the column 11 is detected by the MS unit 2 as a detector has been described. However, the measurement target component is detected by other detectors such as TCD (Thermal Conductivity Detector), FID (Flame Ionization Detector), ECD (Electron Capture Detector) or FPD (Flame Photometric Detector). Such a configuration may be used. In this case, the present invention can be applied not only to a gas chromatograph mass spectrometer equipped with the MS unit 2 but also to a gas chromatograph without the MS unit 2.

  FIG. 5 is a block diagram showing an example of an electrical configuration of a gas chromatograph according to another embodiment. The gas chromatograph according to the present embodiment is a gas chromatograph mass spectrometer provided with a GC unit 1 and an MS unit 2, and the overall configuration thereof is the same as that in FIG. Are given the same reference numerals and detailed description thereof is omitted.

  In the present embodiment, a standard sample containing a measurement target component is supplied to the column 11 via the sample vaporization chamber 12 prior to analysis. Tuning is performed by detecting the standard sample in the MS unit 2 and optimizing various parameters such as a voltage applied to a lens electrode (not shown) provided in the MS unit 2 based on the detected intensity. be able to.

  Specifically, based on each mass-to-charge ratio m / z obtained by detecting the standard sample with the MS unit 2, mass calibration (the detected mass-to-charge ratio is the target mass-to-charge ratio m / z) Confirmation) and detection sensitivity adjustment (optimization of detected mass-to-charge ratio m / z intensity). In the present embodiment, tuning (auto-tuning) can be automatically performed using the He gas supplied from the first gas supply path 15 constituting the first gas supply unit.

On the other hand, except during auto tuning, N ₂ gas is supplied to the column 11 from the second gas supply path 16 constituting the second gas supply unit, including during analysis. The gas supplied from the second gas supply path 16 to the column 11 is not limited to N ₂ gas as long as it is a gas other than He gas, but is preferably less expensive than He gas. Thus, by using gas other than He gas, the usage-amount of He gas can be reduced and a running cost can be reduced.

  The operation of this gas chromatograph is controlled by a control unit 103 including a CPU (Central Processing Unit), for example. The control unit 103 functions as a column switching control unit 131, an auto tuning processing unit 132, an analysis processing unit 133, and the like when the CPU executes a program.

The column switching control unit 131 performs control for switching the gas introduction state to the column 11 by switching the open / close state of the open / close valves 17 and 18. The column switching control unit 131 constitutes a gas switching unit together with the open / close valves 17 and 18. When the opening / closing valve 17 is opened and the opening / closing valve 18 is closed by the column switching control unit 131, the first gas introduction state in which He gas is introduced from the first gas supply path 15 into the column 11 is set. On the other hand, when the opening / closing valve 18 is opened by the column switching control unit 131 and the opening / closing valve 17 is closed, the second gas introduction state in which N ₂ gas is introduced from the second gas supply path 16 into the column 11 is established.

  The auto tuning processing unit 132 performs auto tuning based on the detected intensity of the standard sample detected by the MS unit 2. During auto tuning, the column switching control unit 131 sets the gas introduction state to the column 11 to the first gas introduction state. Thereby, auto-tuning can be performed while introducing He gas into the column 11.

If detection is performed by the MS unit 2 while introducing N ₂ gas instead of He gas into the column 11, the detection intensity at the mass-to-charge ratio m / z = 28 increases. In a state where there is a large amount of N ₂ gas, the detection intensity at the mass-to-charge ratio m / z = 28 becomes too large, so the detection intensity at the mass-to-charge ratio corresponding to the measurement target component becomes relatively small, and the auto tuning is performed well. May not be possible. In addition, since the mass-to-charge ratio m / z = 28 is detected in large quantities, the detector may fail. This is because the mass to charge ratio (m / z = 28) corresponding to N ₂ gas is included in the range of the mass to charge ratio to be measured.

  On the other hand, when detection is performed by the MS unit 2 while introducing He gas into the column 11, the mass-to-charge ratio m / z = 2 is not detected. Since the mass-to-charge ratio (m / z = 2) corresponding to such He gas is not included in the range of the mass-to-charge ratio to be measured, the He gas does not affect auto-tuning. Therefore, an auto-tuning method using He gas has been established conventionally.

The analysis processing unit 133 performs analysis based on the detection intensity of the target sample (actual sample) detected by the MS unit 2. During the analysis, the column switching control unit 131 sets the gas introduction state to the column 11 as the second gas introduction state. Thus, analysis can be performed while introducing N ₂ gas into the column 11.

As described above, when detection is performed by the MS unit 2 while introducing N ₂ gas instead of He gas into the column 11, the detection intensity at the mass-to-charge ratio m / z = 28 increases, but depending on the component to be measured. May be able to perform the analysis without including the mass-to-charge ratio (m / z = 28) corresponding to N ₂ gas in the detection range. In this case, since the analysis can be performed using a gas other than the He gas, the amount of He gas used can be reduced.

  As described above, in this embodiment, analysis is performed using a gas other than He gas. However, since auto-tuning can be performed using He gas for which the method has been established, accurate tuning can be performed. it can. Therefore, even when analysis is performed using a gas other than He gas, auto-tuning can be performed accurately.

FIG. 6 is a flowchart illustrating an example of processing by the control unit 103 during auto tuning. Before auto-tuning is started, N ₂ gas is introduced into the column 11, but when there is an auto-tuning start instruction (Yes in step S301), the first gas is introduced from the second gas introduction state. By switching to the state, He gas is introduced into the column 11 (step S302).

Thereafter, the detected intensity of the N ₂ gas in the MS unit 2 is monitored (step S303), and the detected intensity at the mass-to-charge ratio (m / z = 28) corresponding to the N ₂ gas is equal to or lower than a predetermined first threshold value. If this is the case (Yes in step S304), auto-tuning is started (step S305). Thereby, auto-tuning using He gas can be started in a state where N ₂ gas is sufficiently removed from the column 11. Therefore, since N ₂ gas can be prevented from affecting the result of auto tuning, auto tuning can be performed more accurately.

When auto-tuning is completed (Yes in step S306), N ₂ gas is introduced into the column 11 by switching from the first gas introduction state to the second gas introduction state (step S307). In this way, He gas can be introduced into the column 11 only during auto tuning, and N ₂ gas can be introduced into the column 11 at times other than auto tuning. Thereby, the usage-amount of He gas can be suppressed to the minimum necessary.

FIG. 7 is a flowchart showing an example of processing by the control unit 103 during analysis. Before analysis is started is introduced N ₂ gas to the column 11, in this embodiment, even when there is instruction to start analysis (Yes in step S401), the N ₂ gas as it is to the column 11 be introduced.

Thereafter, the detected intensity of the He gas in the MS unit 2 is monitored (step S402), and whether the detected intensity at the mass-to-charge ratio (m / z = 2) corresponding to the He gas is equal to or lower than a predetermined second threshold value. Is determined (step S403). At this time, if a sufficient time has passed since auto-tuning, the gas in the column 11 is changed from He gas to N ₂ gas. However, if sufficient time has not elapsed since auto-tuning, it waits for the gas in the column 11 to be switched from He gas to N ₂ gas, and the mass-to-charge ratio corresponding to He gas (m / z = 2) When the detected intensity at is less than or equal to the predetermined second threshold (Yes in step S403), analysis is started (step S404).

Thereby, the analysis using the N ₂ gas can be started in a state where the He gas is sufficiently removed from the column 11. Therefore, since He gas can be prevented from affecting the result of analysis, analysis can be performed more accurately. After the analysis is completed (Yes in step S405), N ₂ gas is introduced into the column 11 as it is.

In the present embodiment, the configuration in which He gas is introduced into the column 11 only during auto tuning has been described. However, the present invention is not limited to such a configuration, and at least the He gas is introduced into the column 11 during auto-tuning and the N ₂ gas is introduced into the column 11 during analysis. There may be a period during which gas is introduced into the column 11.

DESCRIPTION OF SYMBOLS 1 GC part 2 MS part 3 Control part 4 Memory | storage part 5 Display part 11 Column 12 Sample vaporization chamber 13 Column oven 14 AFC
DESCRIPTION OF SYMBOLS 15 1st gas supply path 16 2nd gas supply path 17 On-off valve 18 On-off valve 31 Column switching control part 32 Gas flow control part 33 Analysis condition determination part 34 Error notification part 103 Control part 131 Column switching control part 132 Auto-tuning processing part 133 Analysis processing section

Claims (3)

A gas chromatograph for introducing a sample together with a carrier gas into a column and detecting a component to be measured in the sample separated in the column with a detector,
A carrier gas supply unit for supplying a carrier gas;
A column protective gas supply unit for supplying a column protective gas for protecting the column;
Either the carrier gas introduction state in which the carrier gas is introduced into the column from the carrier gas supply unit or the column protection gas introduction state in which the column protection gas is introduced into the column from the column protection gas supply unit. A gas switching section for switching the gas introduction state of
The gas switching unit sets the introduction state of the gas to the column during the analysis of the sample as the carrier gas introduction state, and after the component to be measured is detected by the detector, the column protective gas introduction state during the analysis. A gas chromatograph characterized by switching to.   A gas flow rate control unit that switches the flow rate of the gas flowing in the column according to the type of gas when the carrier gas introduction state is switched to the column protective gas introduction state during the analysis. The gas chromatograph according to claim 1, wherein the gas chromatograph is characterized. An analysis condition determination unit that determines whether or not a predetermined analysis condition is satisfied when the sample is analyzed in a column protective gas introduction state before starting the analysis of the sample;
The gas chromatograph according to claim 1, further comprising: an error notification unit that notifies an error when the analysis condition determination unit determines that the predetermined analysis condition is not satisfied. .

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