Gas chromatograph

Abstract

To provide a gas chromatograph with which it is possible to prevent a filler in a sample vaporization chamber or a split flow path from deviating from a filing position.SOLUTION: A sample gas is generated in a sample vaporization chamber 21 as a liquid sample is evaporated in the inside. A split flow path 4 causes a sample gas in the sample vaporization chamber 21 to be discharged. A split valve 41 is disposed in the split flow path 4 and opened or closed to adjust the flow rate of the sample gas flowing in the split flow path 4. Fillers 26, 421 are filled to a fill position in the sample vaporization chamber 21 or in the split flow path 4. A control unit 7 controls the opening / closing of the split valve 41 so that, when the sample gas in the sample vaporization chamber 21 is discharged from the split flow path 4, the pressure in the sample vaporization chamber 21 decreases at a prescribed gradient smaller than a pressure gradient at which the fillers 26, 421 deviate from the fill position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas chromatograph in which a sample gas generated by vaporizing a liquid sample in a sample vaporization chamber is discharged from a split flow path. [Background technology]

[0002] A gas chromatograph is equipped with a sample vaporization chamber that generates a sample gas by vaporizing a liquid sample therein, and a split flow path that discharges the sample gas in the sample vaporization chamber. The split flow path is provided with a valve (split valve) that opens and closes to adjust the flow rate of the sample gas flowing through the split flow path.

[0003] In the gas chromatograph disclosed in Patent Document 1, a liner (insert) made of a glass tube is inserted into a sample vaporization chamber. The liner is filled with an adsorbent or the like as a filler at a predetermined filling position.

[0004] In the gas chromatograph disclosed in Patent Document 2, a filter is provided in the split flow path. The filter is provided at a predetermined filling position in the split flow path, and components in the sample gas can be collected by the particulate packing material packed in the filter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-256714 A [Patent Document 2] International Publication No. 2017 / 191673 Summary of the Invention [Problem to be solved by the invention]

[0006] When the gas chromatograph is in operation, the pressure inside the sample vaporizer is high. When the gas chromatograph is stopped, the sample gas inside the sample vaporizer can be discharged from the split channel by opening the split valve. If the split valve is fully opened at this time, the pressure inside the sample vaporizer decreases with a large pressure gradient.

[0007] When the pressure in the vaporization chamber decreases due to a large pressure gradient, the filler in the liner in the vaporization chamber may shift from its position. In this case, the thermal effect of the filler on the liquid sample injected into the vaporization chamber varies, resulting in non-uniform vaporization and a deterioration in analytical reproducibility.

[0008] In addition, if the pressure in the sample vaporizer decreases due to a large pressure gradient, the filter in the split channel may shift from its filling position. In this case, the particulate filler packed in the filter may flow out of the filter through the split channel. If the filler particles that flow out of the filter get caught in a part in the split valve located downstream, the split valve may break down.

[0009] The present invention has been made in view of the above-mentioned circumstances, and has an object to provide a gas chromatograph that can prevent the packing material in the sample vaporization chamber or the split flow path from shifting from its packing position. [Means for solving the problem]

[0010] A gas chromatograph according to one aspect of the present invention includes a sample vaporization chamber, a split flow path, a valve, a filler, and a control unit. In the sample vaporization chamber, a liquid sample is vaporized inside to generate a sample gas. The split flow path discharges the sample gas in the sample vaporization chamber. The valve is provided in the split flow path and is opened and closed to adjust the flow rate of the sample gas flowing in the split flow path. The filler is filled in the sample vaporization chamber or at a filling position in the split flow path. The control unit controls the opening of the valve so that, when discharging the sample gas in the sample vaporization chamber from the split flow path, the pressure in the sample vaporization chamber decreases with a pressure gradient smaller than the pressure gradient at which the filler shifts from the filling position. Effect of the Invention

[0011] According to this aspect of the present invention, it is possible to prevent the filler in the sample vaporization chamber or in the split channel from shifting from the filling position. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a gas chromatograph according to one embodiment of the present invention. [Diagram 2] FIG. 4 is a schematic cross-sectional view showing a specific configuration of a sample introduction section. [Diagram 3] FIG. 2 is a block diagram showing the electrical configuration of a gas chromatograph. [Figure 4] 5 is a flowchart showing an example of a process performed by a control unit when controlling a split valve. [Figure 5A] 13 is a diagram showing an example of pressure change when the target value of pressure control in the sample vaporization chamber by the control unit is maintained at a constant gradient. FIG. [Figure 5B] 13 is a diagram showing an example of pressure change when the gradient of the target value of pressure control in the sample vaporization chamber by the control unit is switched midway. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1. Overall configuration of a gas chromatograph 1 is a schematic diagram showing an example of the configuration of a gas chromatograph 100 according to one embodiment of the present invention. The gas chromatograph 100 performs analysis by supplying a sample gas together with a carrier gas into a column 1, and is equipped with a sample introduction section 2, a gas supply flow path 3, a split flow path 4, a purge flow path 5, a detector 6, and the like in addition to the column 1.

[0014] The column 1 is, for example, a capillary column, and is heated in a column oven during analysis. One end of the column 1 is connected to a sample introduction section 2, and a sample gas is introduced into the column 1 together with a carrier gas from the sample introduction section 2 via a column inlet 11. The other end of the column 1 is connected to a detector 6. The detector 6 can be composed of various detectors, for example, a flame ionization detector (FID).

[0015] A sample vaporization chamber 21, which is a space for vaporizing a sample, is defined inside the sample introduction section 2. Specifically, the sample introduction section 2 includes a hollow housing 22 and a septum 23 that seals the housing 22. An opening (not shown) is formed in the housing 22, and the opening is closed by the flexible septum 23. A liquid sample is injected into the sample vaporization chamber 21, and the liquid sample is vaporized in the sample vaporization chamber 21 to generate a sample gas, which is introduced into the column 1 from the column inlet 11 together with a carrier gas. A gas supply channel 3, a split channel 4, and a purge channel 5 are connected to the sample vaporization chamber 21.

[0016] The gas supply flow path 3 is a flow path for supplying carrier gas into the sample vaporization chamber 21 of the sample introduction section 2. The gas supply flow path 3 is provided with, for example, a flow sensor 31 and a total flow valve 32. The flow sensor 31 detects the flow rate of the carrier gas in the gas supply flow path 3. The total flow valve 32 opens and closes the gas supply flow path 3, thereby arbitrarily adjusting the flow rate of the carrier gas in the gas supply flow path 3 between an open state in which the carrier gas is supplied from the gas supply flow path 3 to the sample introduction section 2, and a closed state in which the supply of the carrier gas is stopped.

[0017] The split flow path 4 is a flow path for discharging a part of the gas (mixture of carrier gas and sample gas) in the sample vaporization chamber 21 to the outside at a predetermined split ratio when the carrier gas and sample gas are introduced into the column 1 from the column inlet 11 by the split introduction method. The split flow path 4 is provided with, for example, a split valve 41 and a split filter 42.

[0018] The split valve 41 is opened and closed to adjust the flow rate of the sample gas flowing through the split flow path 4. Specifically, the split valve 41 can arbitrarily adjust the flow rate of the gas in the split flow path 4 between an open state in which gas is discharged from the sample introduction part 2 through the split flow path 4 and a closed state in which the discharge of gas from the sample introduction part 2 is stopped, by opening and closing the split flow path 4. The split filter 42 is provided at a predetermined filling position in the split flow path 4, and components in the sample gas can be collected by the particulate filler 421 filled in the split filter 42. Since no fixture is provided for fixing the filler 421, when an external force is applied to the filler 421, the filler 421 may be displaced from the filling position if the external force is greater than the frictional force.

[0019] In this example, the split filter 42 is provided on the sample introduction section 2 side of the split valve 41, and can capture components derived from the sample that may deteriorate the split valve 41. If the filler 421 shifts from the filling position and flows out of the split filter 42, there is a risk that the particles of the filler 421 may get caught in components such as the split valve 41 located downstream, causing a breakdown.

[0020] The purge flow path 5 is a flow path for discharging undesired components generated from the septum 23 and the like to the outside. The purge flow path 5 is provided with, for example, an inlet pressure sensor 51, a purge valve 52, a purge pressure sensor 53, and a flow path resistance 54. The inlet pressure sensor 51 is provided upstream of the purge valve 52 (on the sample introduction section 2 side) and detects the pressure of the gas in the sample vaporization chamber 21, that is, the pressure of the gas at the column inlet 11 (inlet pressure). The purge valve 52 opens and closes the purge flow path 5, and can arbitrarily adjust the flow rate of the gas in the purge flow path 5 between an open state in which gas is discharged from the sample introduction section 2 through the purge flow path 5, and a closed state in which the discharge of gas from the sample introduction section 2 is stopped. The purge pressure sensor 53 detects the pressure in the purge flow path 5 downstream of the purge valve 52. The flow path resistance 54 is provided downstream of the purge pressure sensor 53 and limits the flow rate of the gas in the purge flow path 5 to a constant value.

[0021] Since the purge flow path 5 has a characteristic that the gas flow rate is low and flows at a substantially constant rate, pressure loss is unlikely to occur, so that the inlet pressure can be detected more accurately by providing the inlet pressure sensor 51 in the purge flow path 5. However, the inlet pressure sensor 51 is not limited to being provided in the purge flow path 5, and may be provided in any other portion (such as the split flow path 4) communicating with the column inlet 11.

[0022] The flow rate sensor 31, the total flow rate valve 32, the split valve 41, the inlet pressure sensor 51, the purge valve 52, the purge pressure sensor 53, and the flow path resistance 54 constitute a flow controller 200. The flow controller 200 is for controlling the flow rates of gas in the gas supply flow path 3, the split flow path 4, and the purge flow path 5, and includes a control unit 7 and a memory unit 8, which will be described later.

[0023] During analysis using this gas chromatograph 100, the open / close state of the gas supply flow path 3 is adjusted by the total flow valve 32, the open / close state of the split flow path 4 is adjusted by the split valve 41, and the open / close state of the purge flow path 5 is adjusted by the purge valve 52. Carrier gas is supplied from the gas supply flow path 3 to the sample vaporization chamber 21 of the sample introduction part 2 at a flow rate that corresponds to the opening degree of the total flow valve 32.

[0024] A liquid sample to be analyzed is injected into sample vaporization chamber 21 by syringe 10. At this time, syringe 10 is inserted into sample vaporization chamber 21 by penetrating septum 23. In this state, the liquid sample is injected into sample vaporization chamber 21 from syringe 10, and the liquid sample is vaporized in sample vaporization chamber 21 to generate sample gas. The generated sample gas is supplied into column 1 together with carrier gas, and the components in the sample gas are separated as it passes through column 1. The separated components in the sample gas are detected by detector 6.

[0025] 2.Specific configuration of the sample introduction section 2 is a schematic cross-sectional view showing a specific configuration of sample introduction section 2. Sample vaporization chamber 21 formed in sample introduction section 2 has a shape elongated in the vertical direction. A cylindrical glass insert 24 is inserted into sample vaporization chamber 21.

[0026] The insert 24 is detachable from the sample vaporization chamber 21. When the insert 24 is inserted into the sample vaporization chamber 21, a space 25 is formed between the inner surface of the sample vaporization chamber 21 and the outer surface of the insert 24, and this space 25 constitutes a gas flow path. That is, the carrier gas supplied from the gas supply flow path 3 into the sample vaporization chamber 21 passes through the insert 24 from the upper end to the lower end, then flows upward from the lower end of the insert 24 through the space 25 outside the insert 24, and flows out into the split flow path 4.

[0027] Filler 26 made of an adsorbent is filled in a predetermined filling position (e.g., the center) in insert 24. Filler 26 is made of a highly adsorbent material, such as wool. When injecting a liquid sample with syringe 10, the tip of syringe 10 inserted into sample vaporization chamber 21 approaches or comes into contact with filler 26, and the liquid sample is injected from the tip of syringe 10 into filler 26.

[0028] Since no fixture is provided for fixing the filler 26, when an external force is applied to the filler 26, the filler 26 may shift from the filling position if the external force is greater than the frictional force. If the tip of the syringe 10 inserted into the sample vaporization chamber 21 is not sufficiently close to or in contact with the filler 26 when injecting a liquid sample due to the filler 26 shifting from the filling position, the liquid sample may not be vaporized uniformly, and the reproducibility of the analysis may decrease. In addition, the sample vaporization chamber 21 may be filled with a catalyst used in a thermal desorption tube or a methanizer as a filler, and even in such a configuration, the reproducibility of the analysis may decrease due to the shift of the filler.

[0029] 3. Electrical configuration of gas chromatograph 3 is a block diagram showing the electrical configuration of the gas chromatograph 100. The flow controller 200 includes a control unit 7 including, for example, a CPU (Central Processing Unit), and the flow sensor 31, the total flow valve 32, the split valve 41, the inlet pressure sensor 51, the purge valve 52, the purge pressure sensor 53, a memory unit 8, and the like are electrically connected to the control unit 7. The memory unit 8 includes a RAM (Random Access Memory) or a ROM (Read Only Memory), and the like.

[0030] The control unit 7 controls the openings of the total flow valve 32, the split valve 41, and the purge valve 52 based on input signals from the flow sensor 31, the inlet pressure sensor 51, and the purge pressure sensor 53. At this time, the control unit 7 appropriately compares the input signals from the flow sensor 31, the inlet pressure sensor 51, and the purge pressure sensor 53 with threshold values ​​stored in the memory unit 8, and controls the openings of the total flow valve 32, the split valve 41, and the purge valve 52 based on the comparison results.

[0031] An operation unit 9 is electrically connected to the control unit 7. The operation unit 9 includes a keyboard or a mouse, and an operator such as a user can perform an input operation by operating the operation unit 9. For example, the above-mentioned threshold value may be stored in the storage unit 8 by the operator operating the operation unit 9.

[0032] 4. Split valve control 4 is a flowchart showing an example of processing by the control unit 7 when controlling the split valve 41. The following describes the control of the opening degree of the split valve 41 by the control unit 7 when the operation of the gas chromatograph 100 is stopped.

[0033] For example, when the gas chromatograph 100 is shut down, when an abnormality occurs in the gas chromatograph 100, or when the gas chromatograph 100 performs a self-diagnosis, a command is generated to request the stop of the operation of the flow controller 200. The command may be generated based on the operation of the operation unit 9, or may be generated automatically based on input signals from various sensors.

[0034] "When the apparatus is shut down" refers to when the gas chromatograph 100 is stopped, and includes when the gas chromatograph 100 is shut down by turning off the power to the gas chromatograph 100. Furthermore, "when an abnormality occurs" includes not only when an abnormality occurs inside the gas chromatograph 100, but also when an abnormality occurs in other devices (such as a pretreatment device) connected to the gas chromatograph 100. "Abnormality" is a concept that includes all kinds of malfunctions of the apparatus, such as gas leakage, detection failure, or high temperature. "Apparatus self-diagnosis" refers to an operation for diagnosing the operating state (including abnormal states) of the gas chromatograph 100 or other devices connected to the gas chromatograph 100.

[0035] When the operation of the flow controller 200 is stopped, the inside of the sample vaporization chamber 21 is pressurized by the inflow of carrier gas and is in a high pressure state. When a request to stop the operation of the flow controller 200 is made (Yes in step S1), the control unit 7 opens the split valve 41 (step S2) to discharge the sample gas in the sample vaporization chamber 21 from the split flow path 4.

[0036] At this time, the control unit 7 controls the opening of the split valve 41 so that the pressure in the sample vaporization chamber 21 decreases with the first pressure gradient (step S3). The first pressure gradient is a pressure gradient smaller than the pressure gradient at which the packing material provided in the gas chromatograph 100 is displaced from the packing position when the sample gas in the sample vaporization chamber 21 is discharged from the split channel 4. The amount of displacement of the packing material from the packing position may be tolerated as long as it is within a range that does not affect the analysis results (such as analysis reproducibility) or does not cause failure of the components (such as the split valve 41). In other words, the first pressure gradient may be set within the range of the above-mentioned amount of displacement. Note that the "gradient" in the present invention is not limited to a linear gradient, but is a concept that also includes a curved gradient.

[0037] The above-mentioned fillers include fillers such as filler 26 that are filled in a filling position in sample vaporization chamber 21, and fillers such as filler 421 that are filled in a filling position in split flow path 4. The filling position of the filler is not limited to the filling positions of fillers 26 and 421, as long as it is within sample vaporization chamber 21 or split flow path 4.

[0038] Pressure control with the first pressure gradient by the control unit 7 continues until the pressure in the sample vaporization chamber 21 detected by, for example, the inlet pressure sensor 51 falls below a threshold value. The threshold value is a pressure higher than atmospheric pressure, and is a pressure at which the filler does not shift (move) from the filling position even if the opening of the split valve 41 is subsequently increased (for example, fully opened).

[0039] The threshold value may be stored in advance in the memory unit 8 by an operator operating the operation unit 9. For example, the operator may perform an operation to determine the threshold value, and then store an appropriate threshold value in the memory unit 8. Specifically, the operation of switching the split valve 41 to fully open at different timings may be performed multiple times to identify the pressure at which the filler shifts from the filling position when the split valve 41 is fully opened, and a pressure that is equal to or slightly higher than the identified pressure may be stored in the memory unit 8 as the threshold value.

[0040] The first pressure gradient (dp / dt) can be calculated, for example, by the following formula (1). dp / dt = F × Ps / V (1) Here, F is the restricted flow rate, Ps is the standard atmospheric pressure (101.325 kPa), and V is the volume of the control system. The restricted flow rate is a flow rate at which the filler does not shift from the filling position, and is, for example, 500 to 700 ml / min, more specifically, about 600 ml / min, but is set appropriately depending on the type of filler and the filling position. In this way, the first pressure gradient can be calculated based on the restricted flow rate, but the calculation formula for the first pressure gradient is not limited to formula (1).

[0041] If the pressure in sample vaporization chamber 21 detected by inlet pressure sensor 51 falls below the threshold value (Yes in step S4) as a result of maintaining pressure control with the first pressure gradient (step S3), controller 7 controls the aperture of split valve 41 so that the pressure in sample vaporization chamber 21 decreases with a second pressure gradient larger than the first pressure gradient (step S5). The second pressure gradient is, for example, the pressure gradient when the aperture of split valve 41 is controlled so that the flow path resistance of split valve 41 is minimized (when fully open). However, although the second pressure gradient is preferably the pressure gradient when split valve 41 is fully open, it is not limited to being fully open as long as the flow path resistance of split valve 41 can be minimized as much as possible.

[0042] The pressure control with the second pressure gradient by control unit 7 is performed at least until the pressure in sample vaporization chamber 21 detected by inlet pressure sensor 51 becomes atmospheric pressure. The pressure control with the second pressure gradient may be terminated based on an input signal from inlet pressure sensor 51, or may be terminated when a certain period of time sufficient for the pressure in sample vaporization chamber 21 to become atmospheric pressure has elapsed.

[0043] 5. Comparison of pressure changes in the sample vaporizer Fig. 5A is a diagram showing an example of pressure change when the target value of the pressure control in sample vaporization chamber 21 by control unit 7 is maintained at a constant gradient. Also, Fig. 5B is a diagram showing an example of pressure change when the gradient of the target value of the pressure control in sample vaporization chamber 21 by control unit 7 is switched midway.

[0044] The example of Fig. 5A shows a case where the target value of the inlet pressure is set to decrease at a constant gradient and the control unit 7 controls the opening degree of the split valve 41. As shown in Fig. 5A, when the target value of the inlet pressure is decreased at a constant gradient, the pressure gradient of the inlet pressure detected by the inlet pressure sensor 51 is a linear constant value until the inlet pressure decreases to a predetermined value or less. However, when the inlet pressure decreases to a predetermined value or less, a deviation occurs between the target value of the inlet pressure and the inlet pressure (actual value) detected by the inlet pressure sensor 51 due to the flow resistance of components such as the split valve 41 and the split filter 42.

[0045] In contrast, when the pressure control of the inlet pressure is switched from the first pressure gradient to the second pressure gradient as in this embodiment, the gradient of the target value of the inlet pressure is switched before the inlet pressure drops to a predetermined value at which the target value of the inlet pressure and the actual measured value diverge, as shown in Fig. 5B. As a result, the pressure gradient of the inlet pressure detected by the inlet pressure sensor 51 is a linear constant value (first pressure gradient) until the gradient of the target value of the inlet pressure is switched.

[0046] Thereafter, the target value of the inlet pressure is switched to atmospheric pressure. In this case, the split valve 41 may be controlled to be fully open, rather than controlling the aperture of the split valve 41 based on the inlet pressure detected by the inlet pressure sensor 51. In this way, by switching the pressure control of the inlet pressure to the second pressure gradient larger than the first pressure gradient, the gas discharge from the sample vaporization chamber 21 can be made quicker.

[0047] 6. Variations The pressure control with the first pressure gradient by the control unit 7 is not limited to a configuration in which the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 is maintained until it falls below a threshold value, but may be a configuration in which the pressure is maintained for a certain period of time. In this case, the certain period of time may be arbitrarily set by the operator, or may be calculated by the control unit 7 based on a history of past input signals from a sensor (such as the inlet pressure sensor 51).

[0048] Also, the pressure control with the second pressure gradient by the control unit 7 may be omitted, and only the pressure control with the first pressure gradient may be performed. In other words, the pressure control with the first pressure gradient by the control unit 7 may be maintained until the pressure in the sample vaporization chamber 21 detected by the inlet pressure sensor 51 becomes atmospheric pressure.

[0049] 7. Aspects It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0050] (Item 1) A gas chromatograph according to one embodiment comprises: a sample vaporization chamber in which a liquid sample is vaporized to generate a sample gas; a split flow path for discharging the sample gas in the sample vaporization chamber; a valve provided in the split flow path and opened and closed to adjust the flow rate of the sample gas flowing through the split flow path; a filler material filled at a filling position in the sample vaporization chamber or in the split channel; The present invention may also include a control unit that controls the opening degree of the valve so that, when the sample gas in the sample vaporization chamber is discharged from the split flow path, the pressure in the sample vaporization chamber decreases with a pressure gradient that is smaller than the pressure gradient at which the filler shifts from the filling position.

[0051] According to the gas chromatograph described in paragraph 1, when the sample gas in the sample vaporization chamber is discharged from the split flow path, the valve opening can be controlled to prevent the filler in the sample vaporization chamber or in the split flow path from shifting from its filling position.

[0052] (2) In the gas chromatograph according to the first aspect, a pressure sensor for detecting a pressure in the sample vaporization chamber; The control unit may control the opening of the valve so that the pressure in the sample vaporization chamber decreases with a first pressure gradient smaller than the pressure gradient at which the filling material shifts from the filling position until the pressure in the sample vaporization chamber detected by the pressure sensor becomes equal to or lower than a threshold value, and then control the opening of the valve so that the pressure in the sample vaporization chamber decreases with a second pressure gradient larger than the first pressure gradient.

[0053] According to the gas chromatograph described in paragraph 2, the filler in the sample vaporization chamber or in the split channel can be prevented from shifting from its filling position by controlling the pressure with a first pressure gradient until the pressure in the sample vaporization chamber detected by the pressure sensor falls below a threshold value. After that, the gas in the sample vaporization chamber can be quickly exhausted by controlling the pressure with a second pressure gradient larger than the first pressure gradient.

[0054] (Item 3) In the gas chromatograph according to item 2, The second pressure gradient may be a pressure gradient obtained when an opening degree of the valve is controlled so as to minimize a flow resistance of the valve.

[0055] According to the gas chromatograph described in the third aspect, after the pressure control in the sample vaporization chamber is switched from the first pressure gradient to the second pressure gradient, the gas in the sample vaporization chamber can be discharged as quickly as possible.

[0056] (Item 4) In the gas chromatograph according to item 1, The filling material may be filled at a filling position in an insert provided in the sample vaporization chamber.

[0057] According to the gas chromatograph described in the fourth aspect, the filler packed in the insert provided in the sample injection chamber can be prevented from shifting from its packed position.

[0058] (Item 5) In the gas chromatograph according to item 1, A filter is provided at a filling position in the split channel, The filler may be packed into the filter.

[0059] According to the gas chromatograph described in the fifth aspect, it is possible to prevent the filler packed in the filter provided in the split flow path from shifting from the packed position. [Explanation of symbols]

[0060] 1 Column 2. Sample introduction section 3 Gas supply channel 4 Split Channel 5 Purge Channel 6. Detector 7 Control section 21 Sample vaporizer 24 Insert 26 Filling material 41 Split Valve 42 Split Filter 51 Inlet pressure sensor 100 Gas chromatograph 200 Flow Controller 421 Filling material

Claims

1. a sample vaporization chamber in which a liquid sample is vaporized to generate a sample gas; a split flow path for discharging the sample gas in the sample vaporization chamber; a valve provided in the split flow path and opened and closed to adjust the flow rate of the sample gas flowing through the split flow path; a filler material filled at a filling position in the sample vaporization chamber or in the split channel; a control unit that controls the opening degree of the valve so that, when the sample gas in the sample vaporization chamber is discharged from the split flow path, the pressure in the sample vaporization chamber decreases with a pressure gradient that is smaller than the pressure gradient at which the filler shifts from the filling position.

2. a pressure sensor for detecting a pressure in the sample vaporization chamber; 2. The gas chromatograph of claim 1, wherein the control unit controls the opening of the valve so that the pressure in the sample vaporization chamber decreases with a first pressure gradient smaller than the pressure gradient at which the filler shifts from the filling position until the pressure in the sample vaporization chamber detected by the pressure sensor becomes equal to or lower than a threshold value, and then controls the opening of the valve so that the pressure in the sample vaporization chamber decreases with a second pressure gradient larger than the first pressure gradient.

3. 3. The gas chromatograph according to claim 2, wherein the second pressure gradient is a pressure gradient obtained when an opening degree of the valve is controlled so that a flow resistance of the valve is minimized.

4. 2. The gas chromatograph according to claim 1, wherein the packing material is packed at a packing position in an insert provided in the sample vaporization chamber.

5. A filter is provided at a filling position in the split channel, 2. The gas chromatograph of claim 1, wherein the packing material is packed in the filter.

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