JPH1096714A - Method and device for analyzing trace gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve gas generation efficiency and analyze speedily and easily trace gas, by depressurizing inside of a sealed container just before or after beginning of heating, by pressurizing it with carrier gas, and by taking out and analyzing generated gas. SOLUTION: Before or after heating section 12 begins heating a sealed container (vial bottle) 14 supporting a sample (d), by sticking a needle 27 into a septum 14a of the vial bottle 14, opening a pressure-reducing valve 48, and depressurizing rapidly and speedily inside of the bottle 14 with a pressure- reducing pomp 49, generation of sample gas (b) is promoted. After a given time from beginning of heating, a valve 50 for carrier gas is opened for a short time and carrier gas (c) is injected into the vial bottle 14 to pressurize its inside atmosphere, and then the valve 50 is closed, a valve 51 for sample is opened, and sample gas (b) is entered into a gas chromatograph 31 using a suction pomp 39. Finally data in the peak area for sample gas (b) is converted to concentration using the calibration-curve relational expression, and the result is displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for separating a small amount of a sample gas such as an organic gas generated from a sample sealed in a closed container such as a vial bottle by a gas chromatograph. .

[0002]

2. Description of the Related Art Conventionally, as a gas analyzer of this type, a sample gas generated from a heated sample is analyzed by a gas chromatograph, and the amount of each component of the sample gas is determined by the peak height,
It is known to display or print out on a screen based on an area (area) and an area ratio.

[0003]

In recent years, however, a standard concentration has been found in the acceptance inspection of a sample such as a molding material or a molded article made of a synthetic resin such as polybutylate terephthalate (PBT) or a magnet wire (MW). There is a demand that it is desirable to detect a concentration relatively close to a standard concentration, even if the concentration is not in a strict sense, and to determine whether the harmful component contained in the sample is acceptable or not.

[0004] However, the conventional gas chromatograph cannot display or print out the gas concentration.
For each component of the sample gas, a standard sample of known concentration must be prepared, and the gas concentration of the sample must be manually converted from the calibration curve created on the graph paper. In addition to the necessity, for example, when the sample easily reacts and changes into another substance, it is impossible to prepare the sample.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is possible to determine the concentration of a calibration gas generated from a sample without preparing a standard sample and grasping a calibration curve thereof in advance. It is an object of the present invention to provide a trace gas analysis method and an apparatus capable of automatically detecting the method. Another object of the present invention is to increase the gas generation efficiency from a sample,
An object of the present invention is to provide a method and an apparatus for analyzing a trace gas, which can easily analyze a trace gas in a short time and can improve the working efficiency of the gas analysis.

[0006]

According to a first aspect of the present invention, there is provided a method for analyzing a trace amount of gas, comprising: heating a sample enclosed in a closed container; A pressure reducing step of reducing the pressure of the sample, a pressurizing step of pressurizing the inside of the closed container with a carrier gas immediately before or immediately after the elapse of a predetermined heating time, and suctioning a sample gas generated in the pressurizing step to supply the carrier to a gas chromatograph. It is characterized by comprising a gas transporting step of transporting with a gas, and an analyzing step of analyzing a sample gas by the gas chromatograph. At the time of the trace gas analysis, it is recommended to purge a piping system for reducing the pressure inside the closed vessel at least after the sample gas analysis step is completed, as described in claim 2.

[0007] The trace gas analyzing apparatus according to the third aspect of the present invention comprises a heating means for the closed vessel for enclosing the sample, a pressure reducing means for reducing the pressure inside the closed vessel immediately before or immediately after the heating operation of the heating means is started, Pressurizing means for pressurizing the inside of the closed container with a carrier gas immediately before or immediately after the elapse of a predetermined heating time by the heating means, and gas conveying means for conveying the sample gas generated by the pressurizing means with the carrier gas. And a gas chromatograph for analyzing the sample gas from the gas transport means.

According to a fourth aspect of the present invention, there is provided a trace gas analyzing apparatus, comprising: a sample transfer means comprising a movable rail movably supported on a fixed rail and having a heating means for detachably heating an airtight container. A syringe means having a syringe needle, and a drive means for removably inserting the syringe needle into a sealed container held at a predetermined position and connecting the syringe needle to a gas chromatograph. According to a fifth aspect of the present invention, at least a gas chromatograph and a sample gas sampling means are housed in a case in close proximity to each other and the sample gas sampling means is mounted on a drawer door provided on a front panel of a case. 5. The gas separating apparatus according to claim 1, further comprising means.

[0009]

According to the method and the apparatus according to the first and third aspects of the present invention, the sample is sealed in a closed vessel and heated, and the inside of the closed vessel is depressurized immediately before or immediately after the start of heating, and then the carrier gas is used. Pressurized, the gas generated from the sample is sucked and gas analysis is performed, so the generation of the sample gas is promoted to increase the gas generation efficiency, and
The time required for gas analysis can be shortened and trace gas analysis can be facilitated by the suction of the sample gas, and the work efficiency of gas analysis can be improved. In addition, by reducing the pressure inside the closed container, the internal atmosphere is diluted and the water content is reduced, and the peak of the sample gas can be prevented from being superimposed on the tailing at the water content. The detection accuracy of the sample gas component generated in the vicinity of moisture can be improved. Further, by pressurizing the inside of the closed container, the suction efficiency of the sample gas is increased, and the gas analysis time can be reduced by the small-capacity suction means.

When the sample gas is analyzed, a piping system for depressurizing the inside of the closed vessel enclosing the sample before or after the sample gas analysis step is completed or before or after the sample gas analysis step is pre-purged or after-purged. By doing so, the analysis accuracy of the sample gas can be improved.

Further, since the heating means is mounted on the sample transfer means, and the syringe needle is disposed to be opposed to the closed container set in the heating means by the driving means, the sample gas is provided. Sampling work is easy.

Further, since at least the sample gas sampling means and the gas chromatograph are housed in one case as in claim 5, the pipes leading to the generated sample gas and the gas chromatograph are short, and the capacity of the suction pump is reduced. Also, the amount of the sample gas adhering to the shortened pipe is reduced, which is convenient for analyzing a trace gas. In addition, since the sample gas sampling means is provided on the drawer door of the front panel, the sample gas sampling operation is further facilitated.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view of a main part showing an example of a gas separating apparatus according to the present invention. In the figure, reference numeral 1 denotes a case, and the case 1 is configured by detachably attaching a front panel 3 to a front end opening of a case main body 2 made of, for example, a rectangular cylinder. The front panel 3 has an inlet 4 for a calibration gas, a sample gas sampling device 5 for sampling gas from a sample, a heating temperature setting / display 6 for the sample, a heating time setting / display 7, and a mode switch. Various switches 8a to 8e such as switches, an LCD mode switching setter 8 having an LCD mode display section 8A, and a printer 9 are set. Reference numeral 10 denotes a key input device, and 11 denotes a CRT chromatogram display. In addition,
In the figure, 8a is a mode change switch, 8b is a start switch, 8c is a reset switch, 8d is a print switch, and 8e is a print paper feed switch.

FIG. 2 is a schematic sectional view showing an example of the sample gas sampling device. The sample gas sampling device 5 includes a heating unit 12 and a syringe driving device 16 and is housed in the case 1 together with a gas chromatograph 31 (FIG. 3) described later. 19 is vial bottle 14
In the heat insulating block, a recess is formed at the center of a heat insulating material made of, for example, Teflon, and a coil heater 21 held by a heater holder 20 is installed in the recess, and a temperature sensor 22 is mounted in contact with the coil heater 21. A drawer door 23 is attached to the heat insulating block 19. On the upper surface of the heat insulating block 19, a stopper 57 made of, for example, an aluminum plate is attached to the support frame 17 via a mounting member (not shown) with a screw body 58 (FIG. 3) in order to prevent the heater holder 20 from coming off. Have been.

The heating unit 12 is attached to a movable rail 25 movably fitted to a fixed rail 24, and is taken out of the front panel 3 by pulling the drawer door 23. Support frame 17 fixed to the fixed rail 24
A syringe drive device 16 is attached to the upper part of the device. A syringe device 28 having a syringe needle 27 is fixed to the other end of the syringe holder 26 fixed to the drive shaft 16a of the drive device 16. The formed pores 26 a communicate with the pipe 52. A stopper 29 made of an aluminum plate is provided on the support frame 17.
The stopper 29 is formed with a through hole 29a (FIG. 3) which is attached with the aluminum cap 14b of the vial 14 and is attached when the syringe needle 27 is pierced and removed from the septum 14a of the vial 14.
The vial 14 is prevented from lifting.

It is recommended that the syringe needle 27 be of a horizontal hole type in which a side hole (not shown) is formed in the side wall of the needle hole whose tip is closed, and is pierced into the septum 14a. In this case, clogging of the needle hole with the septum material can be prevented, and the sample gas generated at the time of pressurization can be uniformly stirred by the ejection of the carrier gas. The proper position detection sensor 13 of the heating unit 12 is constituted by, for example, a limit switch, and is set near the magnet catch 30 at the rear of the fixed rail 24 and the movable rail 25. Is securely held at a predetermined position. The closed container setting sensor 15 is configured by, for example, a photoelectric switch,
The vial 14 is attached to the support frame 17 with a screw 56, and the presence or absence of the setting of the vial 14 can be detected from the presence or absence of the reflected light of the aluminum cap 14b of the vial 14.

FIG. 4 is a schematic piping system diagram showing an example of the internal structure of the gas separating apparatus. In the figure, reference numeral 31 denotes a gas chromatograph housed in a case 1. The gas chromatograph 31 includes an injector 36 having valves 32 and 33 and flow resistances 34 and 35, a calibration gas a and a sample gas from the injector 36. a column 37 for separating the gas component b, and a thermal conductivity (TCD) for detecting the gas component of each of the gases a and b and the carrier gas c
A detector 38 is provided, and the valves 32 and 33 and the flow resistors 34 and 35 are formed on a silicon (Si) wafer by a semiconductor technology, and the calibration gas a and the sample gas b are transported by a carrier gas c to form a column. The gas component separated at 37 can be detected by the thermal conductivity (TCD) detector 38.

The TCD detector 38 is formed, for example, by connecting a nickel (Ni) wire to a Wheatstone bridge, and obtains an output proportional to the concentration of a gas component. The sample gas b is sucked by the suction pump 39, and the valves 32,
By adjusting the operation timing of 33, the amount of gas injected into the column 37 can be adjusted. The gas chromatograph 31 is housed in, for example, an inner case 41, and its detection operation is substantially the same as that of the conventional technique described in “Measurement Technique Extra Edition”, pp. 105 to 109, issued in 1989. Therefore, the detailed description is omitted.

For the carrier gas c, for example, a He gas cylinder (not shown) containing helium (He) gas, which is an inert gas, is connected to the carrier gas inlet port 42, and a pressure regulating valve 43 and a flow resistance The excess gas is conveyed to the column 37 through the carrier gas outlet port 44 through the three-way valve 40 and the suction pump 39.
Is released into the atmosphere from That is, when the amount of the gas component separated in the column 37 is sequentially detected by the TCD detector 38, the pressure of the carrier gas c is adjusted by the valve 43 and the pressure gauge 45, and the carrier flowing through the flow resistor 35 and the column 37 is adjusted. By adjusting the flow rate of the gas c, the calibration gas a and the sample gas b are carried into the column 37 from the valves 32 and 33, and the peak of the gas component with respect to the detected time (retention time RT). , The detection speed, interval, etc., can be adjusted.

Reference numeral 46 denotes a calibration gas valve for the calibration gas a.
For example, a calibration gas cylinder (not shown) filled with toluene having a concentration of 10 ppm is connected to the calibration gas introduction port 4,
When the valve 46 is opened and suction is performed by the suction pump 39,
The predetermined retention time R. At the position of T, a peak having a width and a height corresponding to the concentration of the gas component appears. The width and height of the peak according to the concentration of the gas component are determined by the CR shown in FIG.
The area of the peak can be visually recognized on the screen of the T chromatogram display 11 and displayed on the screen as an area value.

The vial 1 heated by the heating unit 12
4 holds the sample gas b generated from the sample d inside in a sealed state. Immediately before or immediately after heating the vial 14 with the heating unit 12, the syringe needle 27 is inserted into the septum 14 a of the vial 14, the decompression valve 48 is opened, and the suction is rapidly and quickly performed by the decompression pump 49. The internal atmosphere of the vial 14 is reduced in pressure, and the generation of the sample gas b can be promoted. In addition, by heating the vial 14, moisture and air contained in the internal atmosphere are reduced, the tailing of the air and moisture peaks in the chromatogram is improved, and the detection accuracy of the gas component peak area in the sample gas b is improved. Can be improved.

After a predetermined heating time has elapsed, the carrier gas valve 50 is opened for a short time, the internal atmosphere of the vial 14 is pressurized, the valve 50 is closed, and then the sample gas sample valve 51 is opened. , Suction pump 39
When the sample gas b is sucked in, the sample gas b can be quickly taken into the gas chromatograph 31 in combination with the pressurizing effect of the internal atmosphere. After pressurizing the internal atmosphere of the vial 14, the syringe needle 27
, The operation of the pressure reducing pump 49 may be stopped. However, without removing the syringe needle 27, the operation of the pressure reducing pump 49 may be stopped and the pressure reducing valve 48 may be kept closed. It goes without saying that it is good.

The sample gas sampling device 5 can be housed in the vicinity of one case 1 together with the gas chromatograph 31 to shorten the length of the pipe 52. The amount of the attached sample gas b is reduced, and the trace gas can be analyzed with high accuracy. In addition, since the sample gas sampling device 5 and the gas chromatograph 31 are shared and housed in the case 1, the gas analyzer becomes compact and easy to handle.

FIG. 5 is a schematic block diagram showing an example of the system configuration of the above-mentioned gas separation apparatus. In the figure,
Central processing unit (CPU) consisting of one-chip microcomputer
Reference numeral 61 denotes an operation procedure of the gas chromatograph 31, a memory 61A for creating a screen of a chromatogram and displaying the screen on the CRT display 11, a procedure for calculating data and an area analyzed by the gas chromatograph 31, and a peak area of the sample gas b. RO storing a procedure for comparing with the peak area of the calibration gas a and converting the concentration into the concentration from the gas chromatograph 31
M / RAM 61BB and CRT / LCD driver 6
1C and the like.

The key input device 10 controls the weight of the sample d by the CPU.
The printer controller 62 is controlled by the output of the CPU 61 to output the analysis result of the gas chromatograph 31 to the printer 9 and to control the operation of the printer 9. The I / O board 63 includes an input / output device and a CPU 61.
It is an interface that matches with. The LCD mode switch setting unit 8 selects the analysis of the calibration gas a, displays the chromatogram by enlarging or reducing it, changes and sets the current time, and the like. The mode name and set value selected in
This is displayed on the D-mode display section 8A.

The heating unit 12 heats the vial 14,
The heating unit 12 uniformly heats the internal sample d. The heating temperature and the heating time are set by the heating temperature setting / display 6 and the heating time setting / display 7. The detected temperature is the above-mentioned heating temperature setting / display 6
Will be displayed as feedback. The heating unit proper position detection sensor 13 detects whether or not the vial 14 is appropriately facing the syringe device 28, and the closed container setting sensor 1
Reference numeral 5 indicates whether the vial 14 is set or not. Reference numeral 16 denotes a syringe driving unit, 66 denotes a timer for setting the operation timing of each valve, the syringe driving unit 16 and the like, and 67 denotes a sequence control unit that performs sequence control of each valve and the syringe driving unit 16 based on a signal from each sensor.

Next, the operation of the above configuration will be described with reference to FIGS.
This will be described according to the flowchart shown in FIG. First, the operation of creating a calibration curve will be described with reference to the flowchart shown in FIG. A calibration gas cylinder (not shown) whose concentration is known is connected to the calibration gas inlet port 4 in FIG. 4, and the calibration curve creation mode is set by the mode changeover switch 8a of the mode changeover setting unit 8 shown in FIGS. Is selected (step S70), and that is displayed on the LCD mode display section 8A.

When the concentration value of the calibration gas a, for example, 10 ppm is inputted by the key input device 10 (step S7).
1) The density value is stored in the ROM / RAM 61B of the CPU 61.
And is displayed on the LCD mode display section 8A (step S72), so that erroneous input can be prevented. By selecting the above calibration curve mode, the valve 48 for the pressure reducing pump, the valve 50 for the carrier gas,
Close both the sample valves 51 and the calibration gas valve 4
6 is opened and the calibration gas a is taken into the gas chromatograph 31 for a predetermined time by the input signal of the concentration value (step S).
73), gas analysis is started (step S74), and when the analysis is completed (step S75), the data is stored in the ROM / RAM 61B of the CPU 61.

Further, when the analysis mode is selected by the mode changeover switch 8a of the mode changeover setter 8 (step S76), the retention time R.R. A chromatogram having a peak according to T is displayed on the CRT display 11 (step S77), and a relational expression between the area value and the density value of the peak is created by the CPU 61 (step S78), and the result is stored in the ROM / RAM 6 of the CPU 61.
1B (step S79) and, if necessary, printed by the printer 9 (step S80).

When the calibration curve creation data is stored, the process proceeds to the analysis of the sample d. Next, the analysis operation of the sample d will be described with reference to the flowchart shown in FIG. First, the heating unit 12 is heated to a predetermined temperature by the heating temperature setting / display 6 (step S81), and it is determined whether the temperature is the predetermined temperature (step S82). If the result of the determination is Yes, the sample weight input mode is selected by the mode switching setter 8 (step S83). After the selection is displayed on the LCD mode display section 8A, the weight of the sample d is input using the key input device 10 (step S84), and the result is also displayed on the display section 8A (step S85). .

When the time is set on the heating time setting / display 7 (step S86) and the vial 14 is set in the heating section 12, the closed vessel setting sensor 15 detects its presence (step S87), and the heating section If 12 is properly set (step S88), the sequence control unit 67 starts the subsequent sequence control by the signal from the heating unit proper position detection sensor 13. When the presence of the vial 14 is confirmed by the detection signal of the closed vessel setting sensor 15, the syringe driving unit 16 operates with the calibration gas valve 46, the carrier gas valve 50, and the sample valve 51 all closed. Then, the syringe device 28 is lowered, and immediately before or immediately after the vial 14 is heated by the heating unit 12, the syringe needle 27 is inserted into the septum 14a of the vial 14 and inserted into the internal space of the vial 14. When the depressurizing valve 48 is momentarily opened and the depressurizing pump 49 is operated to quickly and quickly aspirate, the internal atmosphere of the vial 14 is depressurized (step S89), thereby promoting the generation of the sample gas b.

After the internal space of the vial 14 is depressurized, the syringe needle 27 is pulled out, and when a predetermined heating time comes (step S90), the syringe needle 27 is inserted again into the vial 14, and the carrier is inserted. Only the gas valve 50 is opened, and the carrier gas c is carried into the vial 14 and pressurized (step S9).
1). When the carrier gas valve 50 is closed and the sample valve 51 is opened in this pressurized state, the generated sample gas b is taken into the gas chromatograph (GC) 31 (step S92). Of course, at this time, since the suction pump 39 of the gas chromatograph 31 is operating, the pressurized state of the sample gas b inside the vial 14 can be reliably and quickly achieved. When the sample gas b is taken into the gas chromatograph 31 for a predetermined time, the analysis of the sample gas b is started (step S93), and the analysis data is stored in the ROM / RAM 61B.

When the sample gas b has been taken in and analyzed (step S94), the syringe needle 27 is withdrawn, the sample valve 51 is closed, and the pressure reducing valve 48 is closed.
Is opened, and the decompression pump 49 is operated, so that the syringe needle 2
Syringe device 28 and piping 5 from 7 to vacuum pump 49
2 is purged, the analysis of the sample gas b is completed, and when the analysis mode is selected (step S95), the chromatogram is displayed on the CRT display 11 (step S9).
6). On the other hand, the data of the peak area of the sample gas b is converted into the concentration by the relational expression of the calibration curve by the CPU 61 (step S97), and the converted concentration is displayed on the LCD display 11 and, if necessary, the printer 9 is operated. Can be printed out (step S98).

FIG. 8 is a characteristic diagram showing the relationship between the concentration of the calibration gas and the area detected by the gas chromatograph by a calibration curve.
It was created based on the analysis data for standard toluene shown in FIG. In FIG. 8, standard toluene was used as the calibration gas a, and the concentration of this standard toluene (1 to 1) was used.
100 ppm) on the horizontal axis and the area (arbitrary unit) on the vertical axis, it is understood that the obtained calibration curve Ka has a proportional relationship. Thus, when the standard toluene is used as the calibration gas a, the chromatogram has only one peak, and
The peak is composed of a steep triangular wave having an isosceles triangular shape, and the trailing line of the triangular wave does not have a tailing composed of a slow falling curve. It is optimal as a.

FIG. 10 is a characteristic diagram showing the relationship between the weight of the sample and the area detected by the gas chromatograph as a calibration curve.
A magnet wire M / W is used as the sample d,
It is understood that the weight (0.25 to 3 g) is proportional to the calibration curve Kb obtained with the abscissa and the peak area (arbitrary unit) as the ordinate. That is, FIG.
(B) and (C) are characteristic diagrams showing the relationship between the weight of the M / W and the areas of the peaks in the chromatogram (Gw) shown in FIG. 11 by a calibration curve Kb, and are shown in FIG. It is created based on the linearity analysis data.

Each of the retention times R.R. Comparing the peaks at every T (seconds), it is understood that there is a proportional relationship between the weight of the M / W and the area. As described above, the standard toluene which is the calibration gas a has a proportional relationship Ka between the concentration and the area shown in FIG.
Since / W has a proportional relationship Kb shown in FIG. 10 between the weight and the area, if the area of each component peak of the M / W is converted into the concentration by the calibration curve Ka, the conventional A standard sample corresponding to the above M / W is prepared as in
Without previously grasping the calibration curve, the concentration of the sample gas can be extremely easily and simply detected for all the components, and the detection is performed automatically in a short time.

FIGS. 13 and 14 show the results of the M / W reproducibility test. According to the test results, FIG.
When the M / W has the same weight, the areas of the peaks and in the chromatogram are almost equal, are within the standard deviation within the specified range, and it is confirmed that there is reproducibility. The peaks in the chromatogram shown in FIG. 11 are obtained by printing out the image displayed on the CRT display 11 by the printer 9, and the M /
The sample gas b generated from W is, for example, an organic gas such as phenol or cresol.

As is clear from the above description, the sample d is sealed in the vial 14 and heated. Immediately before or immediately after the start of heating, the inside of the vial 14 is depressurized and then pressurized with the carrier gas c. Since the gas b generated from the sample d is sucked to perform the gas analysis, the generation of the sample gas b can be promoted to increase the gas generation efficiency, and the gas analysis can be shortened by sucking the sample gas. And the simplification of trace gas analysis can be achieved, and the working efficiency of gas analysis can be improved. Further, by reducing the pressure inside the vial bottle 14, the internal atmosphere is diluted and the water content is reduced, and a predetermined peak among the above-mentioned peaks is superimposed on the tailing (not shown) of this water content peak. To prevent
The detection accuracy of the sample gas component generated in the vicinity of the water can be improved. Further, by pressurizing the inside of the vial 14, the suction efficiency of the sample gas b can be increased, and the small volume suction pump 39 can contribute to shorten the gas analysis time.

After or before and after the sample gas d analyzing step is completed, a pipe system such as a pipe 52 for depressurizing the inside of the vial 14 in which the sample d is sealed is pre-purged or after-purged, thereby obtaining the sample gas d. The analysis accuracy of b can be improved.

In the gas analysis, the movable rail 2
Since the heating unit 12 is mounted on the heating unit 5 and the syringe device 28 is disposed opposite to the heating unit 12 by the syringe driving device 16 to perform the sampling operation of the sample gas b, the sampling operation is easy. Further, since the sample gas sampling device 5 and the gas chromatograph 31 are housed in one case 1, the pipe 52 for guiding the generated sample gas b to the gas chromatograph 31 is shortened, and the capacity of the suction pump 39 is reduced. The shortened pipe 52 and small-capacity suction pump 39 can reduce wasteful consumption of the sample gas b adhering to these inner walls, which is convenient for the analysis of trace gases. Moreover, since the sample gas sampling device 5 is set on the drawer door 23 of the front panel, the sampling operation of the sample gas b is further facilitated.

In the above embodiment, the gas analysis of the magnet wire M / W was described as the sample d. However, for example, a molding material or molded article made of a synthetic resin such as polybutylate terephthalate (PBT),
It goes without saying that the present invention can be applied to gas analysis of other products and parts. Incidentally, the sample gas b generated from the PBT is, for example, tetrahydrofuran (TH
Organic gas such as F) and butene. In the above embodiment, since the sample d is a solid made of the magnet wire M / W, the sample d is input and displayed by weight. However, when the sample d is a liquid, the input is input by volume. Needless to say, gas analysis may be performed.

[0042]

According to the first and third aspects of the present invention, the sample is sealed in a closed vessel and heated, and immediately before or immediately after the start of heating, the inside of the closed vessel is depressurized and then pressurized with a carrier gas. Since the gas generated from the sample is sucked for gas analysis, the generation of the sample gas is promoted to increase the gas generation efficiency, and the time required for the gas analysis is shortened and the trace gas analysis is performed by sucking the sample gas. Can be achieved, and the working efficiency of gas analysis can be improved. In addition, by reducing the pressure inside the closed container, the internal atmosphere is diluted and the water content is reduced, and the peak of the sample gas can be prevented from being superimposed on the tailing at the water content. The detection accuracy of the sample gas component generated in the vicinity of moisture can be improved. Further, by pressurizing the inside of the closed container, the suction efficiency of the sample gas is increased, and the gas analysis time can be reduced by the small-capacity suction means.

According to the second aspect of the present invention, since the piping system for depressurizing the inside of the closed vessel is purged at least after the sample gas analysis step is completed, the piping system is constantly cleaned and the sample gas is purged. Analysis accuracy can be improved.

According to the fourth aspect of the present invention, the heating means is mounted on the sample transfer means, and the syringe needle is arranged to be opposed to the closed container set in the heating means by the driving means. The sampling operation of the sample gas is easy.

Further, according to the fifth aspect of the present invention, since at least the sample gas sampling means and the gas chromatograph are housed in one case, the pipe for guiding the generated sample gas and the gas chromatograph is short, and the capacity of the suction pump is reduced. The amount of sample gas attached to the shortened pipe is reduced, which is convenient for trace gas analysis.
Since the sample gas sampling means is set on the drawer door of the front panel, the sampling operation of the sample gas is further facilitated.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a main part showing an example of a gas separating apparatus according to the present invention.

FIG. 2 is a sectional view showing a main part of the gas separating apparatus.

FIG. 3 is a plan view showing a main part of the gas separating apparatus.

FIG. 4 is a schematic piping system diagram showing an example of an internal structure of the gas separating apparatus.

FIG. 5 is a schematic block diagram showing an example of a system configuration of the gas separation apparatus.

FIG. 6 is a flowchart for explaining an operation of analyzing a calibration gas by the gas analyzer.

FIG. 7 is a flowchart for explaining an operation of analyzing a sample gas by the gas analyzer.

FIG. 8 is a calibration curve characteristic diagram showing a relationship between a concentration of a calibration gas and an area of a peak detected by a gas chromatograph.

FIG. 9 is a diagram showing linearity analysis data of the calibration gas shown in FIG. 8;

FIG. 10 is a calibration curve characteristic diagram showing a relationship between a sample weight and areas of different peaks detected by a gas chromatograph.

FIG. 11 is a characteristic diagram showing an example of a chromatogram of a sample gas.

12 is a diagram showing linearity analysis data of the calibration curve shown in FIG.

FIG. 13 is a diagram showing data of a reproducibility test result of the calibration curve.

FIG. 14 is a diagram showing other data of a reproducibility test result of the calibration curve.

[Explanation of symbols]

 Reference Signs List 1 Case 3 Front panel 4 Calibration gas inlet 5 Sample gas sampling device 6 Heating temperature setting / display 7 Heating time setting / display 12 Heating unit 14 Sealed container (vial bottle) 16 Syringe drive device 24 Fixed rail 25 Movable rail 27 Syringe needle 28 Syringe device 31 Gas chromatograph 39 Suction pump 48 Pressure reducing valve 49 Pressure reducing pump 50 Carrier gas valve 51 Sample valve 52 Piping a Calibration gas b Sample gas c Carrier gas

[Procedure amendment]

[Submission date] December 12, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Trace gas analysis method and apparatus

Claims (5)

[Claims] 1. A heating step of heating a sample sealed in a closed container, a depressurizing step of depressurizing the inside of the closed container immediately before or immediately after the start of the heating step, and immediately before or immediately after the elapse of a predetermined heating time. A pressurizing step of pressurizing the inside of the closed container with a carrier gas, a gas transporting step of sucking the sample gas generated in the pressurizing step and transporting the sample gas with the carrier gas to a gas chromatograph, and transferring the sample gas by the gas chromatograph. An analysis step of analyzing the trace gas. 2. The trace gas analysis method according to claim 1, wherein a piping system for depressurizing the inside of the closed vessel is purged at least after the sample gas analysis step is completed. 3. A means for heating a closed container for enclosing a sample,
A pressure reducing means for reducing the pressure inside the closed container immediately before or immediately after the start of the heating operation of the heating means, and a pressurizing method for pressurizing the inside of the closed container with a carrier gas immediately before or immediately after the elapse of a predetermined heating time by the heating means. Means, a gas conveying means for conveying the sample gas generated by the pressurizing means with a carrier gas, and a gas chromatograph for analyzing the sample gas from the gas conveying means. apparatus. 4. A sample transfer means comprising a movable rail which is movably supported by a fixed rail and has heating means for removably heating a closed container, a syringe means having a syringe needle, and a predetermined position. 4. A trace gas analyzing apparatus according to claim 3, further comprising a driving means for removably inserting a syringe needle into the closed container held by the device and connecting the syringe needle to a gas chromatograph. 5. The apparatus according to claim 1, wherein at least the gas chromatograph and the sample gas sampling means are housed in the case close to each other, and the sample gas sampling means is mounted on a drawer door provided on a front panel of the case. The gas separation apparatus according to any one of claims 1 to 4, wherein: