JP2005003387A - Sample introduction method and device in gas component analysis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sample introduction method and a device in gas component analysis capable of introducing a sample as it is without dilution and without using a carrier gas. <P>SOLUTION: This method has a procedure for sucking sample gas in a sample container as much as a prescribed quantity by a pump 1 connected to the sample container 9, capable of changing a discharge target to a sample introduction path 6 of an analyzer in the state where the connection part is attached to the sample container, and a procedure for discharging the sample gas of the prescribed quantity sucked by the pump to the analyzer side through the sample introduction path. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sample introduction method and apparatus in gas component analysis such as breath analysis, and more particularly to a sample introduction method and apparatus in which a sample can be directly introduced into an analyzer without being diluted with a carrier gas.
[0002]
[Prior art]
FIG. 6 shows a conventional sample introduction method and apparatus in gas component analysis such as breath analysis. A sample gas such as exhaled breath is enclosed in a sample tube 9. The sample gas in the sample tube 9 is introduced into the analyzer for component analysis. For example, a mass spectrometer is used as the analyzer. For this purpose, the carrier gas is introduced into the sample tube 9 and the sample gas is introduced into the analyzer together with the carrier gas via the sample introduction path 12.
[0003]
The carrier gas is an inert gas such as helium or nitrogen, and is introduced into the sample tube 9 from the cylinder 10 through the carrier gas introduction path 11. The carrier gas introduction path 11 and the sample tube 9 are connected to each other by inserting a needle provided at the tip of the carrier gas introduction path 11 into the plug portion of the sample tube 9. Similarly, a needle provided at the tip of the sample introduction path 12 is inserted into the plug portion of the sample tube 9, and the sample introduction path 12 and the sample tube 9 are connected.
[0004]
[Problems to be solved by the invention]
In the conventional sample introduction method, since the sample gas is introduced into the analyzer in a state diluted with the carrier gas, there is a problem that the sensitivity of the analyzer is inevitably lowered. Further, it is necessary to stab the sample tube 9 with two needles for introducing the sample, and the connection work between the sample tube 9 and each introduction path is troublesome. It is possible to use a double needle in which two needles are combined into one. However, the double needle has a complicated structure and is expensive, and the needle has a large diameter and is difficult to pierce. It was. Furthermore, since the concentration of the sample gas in the sample tube 9 is gradually diluted by the carrier gas and the concentration of the sample gas is reduced with time, the measurement is inconvenient.
[0005]
Further, it is conceivable that the sample gas in the sample tube 9 is sucked by a suction pump and introduced into the analyzer as it is without using a carrier gas. However, in this way, the amount of the sample gas in the sample tube 9 is small. As a result, the introduction pressure of the sample gas decreases, which affects the measurement. In particular, when the analyzer is a gas chromatograph, a change in the pressure of the sample gas immediately affects the adsorption / desorption of the entire column, so that the measurement results are greatly adversely affected.
[0006]
It has also been a conventional practice to connect a sample introduction conduit to a syringe pump, etc., provide a connection needle at the tip of the conduit, and manually switch the connection destination of the connection needle to introduce the sample gas into the analyzer. It was broken. That is, after inserting the connecting needle into the stopper of the sample tube and sucking the sample gas into the pump, the connecting needle is pulled out of the sample tube and inserted into the sample introduction part of the analyzer, and the sample gas is introduced into the analyzer. It was. However, when the connection destination of the connection needle is manually switched, air is inevitably introduced from the connection needle due to the negative pressure in the pump, and the composition of the sample gas is changed by mixing with the sample gas. There was a problem.
[0007]
Therefore, the present invention provides a sample introduction method and apparatus in gas component analysis that can directly introduce the sample into the analyzer without using a carrier gas and without diluting it, and can solve these problems. The purpose is to do.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the sample introduction method in the gas component analysis of the present invention is connected to the sample container, and the discharge destination is set to the sample introduction path of the analyzer while the connection portion is attached to the sample container. A procedure for sucking a predetermined amount of sample gas in the sample container by a pump that can be changed to a predetermined amount, and a procedure for discharging a predetermined amount of the sample gas sucked by the pump to the analyzer side through the sample introduction path It has.
[0009]
Further, in the sample introduction method in the gas component analysis described above, the pump is a piston / cylinder type pump, and after the sample gas is sucked into the pump, the discharge destination of the pump is changed to the sample introduction path side. It is preferable.
[0010]
In addition, the sample introduction device in the gas component analysis of the present invention includes a pump that is connected to the sample container and can change the discharge destination to the sample introduction path of the analyzer while the connection portion is attached to the sample container. And a control means for controlling the pump so that the sample gas in the sample container is sucked by the pump, and then discharging the sucked sample gas to the sample introduction path side.
[0011]
In addition, the sample introduction device in the gas component analysis of the present invention includes a pump that discharges the sample gas that has been sucked in after a predetermined amount of sample gas has been sucked, and a sample container or analyzer containing the sample gas. Switching means for communicating with any one of the sample introduction paths, the pump and the switching means are controlled so as to cause the pump and the sample container to communicate with each other, and the pump performs a suction operation. And a control means for causing the pump to perform a discharge operation.
[0012]
In the sample introduction apparatus in the gas component analysis, the pump is preferably a piston / cylinder pump.
[0013]
Moreover, in the sample introduction apparatus in the gas component analysis described above, it is preferable that the pump has a suction volume set larger than the volume of the sample container.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a sample introduction method and apparatus according to the present invention. A sample gas such as exhaled breath is enclosed in a sample tube 9 as a sample container. The sample gas in the sample tube 9 is introduced into the analyzer for component analysis. As the analyzer, for example, a mass spectrometer can be used.
[0015]
A needle as a connection portion provided at one end of the connection path 5 is inserted into the plug portion of the sample tube 9, and the sample tube 9 and the connection path 5 are connected. The other end of the connection path 5 is connected to the rotary valve 3. The rotary valve 3 is connected to a sample introduction path 6 for introducing a sample into the analyzer, and further connected to the pump 1 via the sample path. By changing the conduction state of the rotary valve 3, either the connection path 5 or the sample introduction path 6 can be selectively communicated with the pump 1. That is, the rotary valve 3 functions as switching means for switching the discharge destination of the pump 1. As the switching means, a switching valve other than the rotary valve may be used. For example, a switching device having the same function can be configured using a three-way valve, a stop valve, or the like.
[0016]
The pump 1 is preferably one that has good airtightness and little sample leakage, and specifically, a piston / cylinder pump or the like (for example, a syringe pump) can be used. When a syringe pump is used, it is desirable to improve the gas tightness by sealing the sliding portion with an O-ring or the like. Further, the plug portion of the sample tube 9 is preferably a thick rubber portion that is slightly hard from the viewpoint of airtightness.
[0017]
Drive means 2 for causing the pump 1 to perform a suction operation or a discharge operation is provided in the vicinity of the pump 1. The drive unit 2 causes the pump 1 to perform a suction operation or a discharge operation by reciprocating the piston of the pump 1 in the direction of the arrow. The driving unit 2 and the rotary valve 3 are controlled by a control unit 4. That is, switching of the conduction state of the rotary valve 3 and the suction or discharge operation of the pump 1 are controlled by the control means 4.
[0018]
With respect to the suction operation of the pump 1, the movement amount (suction volume) and suction time of the piston of the syringe pump are controlled by the control means 4. Regarding the discharge operation of the pump 1, the discharge speed and the discharge pressure are controlled by the control means 4. At this time, it is desirable to control the discharge pressure to be substantially constant. Note that it is preferable that the entire amount of the sample gas required for measurement is sucked into the pump by a single suction operation, and the sample gas is introduced into the analyzer at a constant flow rate and a constant pressure by a discharge operation. In order to introduce at a constant pressure, a constant pressure valve may be provided on the inlet side of the analyzer. The sample gas sent from the pump 1 to the sample introduction path 6 passes through the dehumidifying filter 7 and the column 8 and is sent to the analyzer.
[0019]
2 and 3 are diagrams showing the operation of the sample introduction apparatus of the present invention. When the sample tube 9 is connected to the connection path 5, as shown in FIG. 2, the conduction state of the rotary valve 3 is switched so that the pump 1 and the connection path 5 are communicated. Then, the pump 1 is caused to perform a suction operation. These operations are performed by controlling the rotary valve 3 and the driving means 2 by the control means 4.
[0020]
Assuming that the maximum pump volume during suction of the pump 1, that is, the suction volume is P, the volume inside the sample tube 9 is S, and the sample mass in the sample tube 9 is W, the suction operation of the pump 1 causes almost W · P A sample having a mass of / (P + S) can be sucked into the pump 1. Therefore, the suction volume of the sample can be increased by increasing the suction volume P of the pump 1 as much as possible as compared with the volume S of the sample tube 9. For this reason, it is preferable to set the suction volume P of the pump 1 larger than the volume S of the sample tube 9.
[0021]
When the pump 1 sucks a sufficient amount of sample, next, as shown in FIG. 3, the conduction state of the rotary valve 3 is switched so that the pump 1 and the sample introduction path 6 communicate with each other. Then, the pump 1 is caused to perform a discharge operation. These operations are performed by controlling the rotary valve 3 and the driving means 2 by the control means 4.
[0022]
The sample gas is pressurized by the pump 1, passes through the pipes such as the sample introduction path 6, the dehumidifying filter 7 and the column 8, and is introduced into the analyzer. If the volume in these pipes is smaller than the volume of the sample gas discharged from the pump 1, the entire pipe can be filled with the sample gas, and the sample gas can be introduced into the analyzer. Further, if the volume in the pipe is smaller than the volume of the sample gas discharged from the pump 1, a back flush mechanism for the column 8 can be added.
[0023]
As a specific numerical example, if the volume S of the sample tube 9 is 12 mL and the suction volume P of the pump 1 is 40 mL, 9.23 mL (at 1 atm) of sample gas can be sucked into the pump 1. it can. At this time, in the apparatus used for the analysis, the volume in the pipe on the side of the sample introduction path 6 was 3.9 mL, so that a sufficient amount of sample gas necessary for the measurement could be introduced into the analyzer. .
[0024]
FIG. 4 is a diagram showing another embodiment of the sample introduction method and apparatus of the present invention. Portions common to those of the sample introduction apparatus in FIG. The sample introduction apparatus in FIG. 4 differs from the sample introduction apparatus in FIG. 1 in the configuration of the pump 13. For this reason, the rotary valve 3 is unnecessary. A sample gas such as exhaled air is sealed in a sample tube 9, and the sample gas in the sample tube 9 is introduced into an analyzer for component analysis.
[0025]
The pump 13 is provided with a suction port and a discharge port, a check valve 13a is provided in the vicinity of the suction port, and a check valve 13b is provided in the vicinity of the discharge port. The check valve 13a is arranged to pass only the flow of the sample gas in the suction direction, and the check valve 13b is arranged to pass only the flow of the sample gas in the discharge direction. In addition, this pump 13 is also preferably one having good airtightness and little sample leakage.
[0026]
A needle as a connection portion provided at one end of the connection path 5 is inserted into the plug portion of the sample tube 9, and the sample tube 9 and the connection path 5 are connected. The other end of the connection path 5 is connected to a check valve 13 a on the suction port side of the pump 13. In addition, a sample introduction path 6 for introducing a sample into the analyzer is connected to the check valve 13b on the discharge port side. Therefore, during the suction operation of the pump 13, the check valve 13a is opened and the check valve 13b is closed, and the sample gas in the sample tube 9 is sucked into the pump 13 through the connection path 5 and the check valve 13a. Is done. During the discharge operation of the pump 13, the check valve 13a is closed and the check valve 13b is opened, and the pressurized sample gas is introduced into the analyzer through the check valve 13b and the sample introduction path 6. The
[0027]
Drive means 2 for causing the pump 13 to perform a suction operation or a discharge operation is provided in the vicinity of the pump 13. The drive unit 2 causes the pump 13 to perform a suction operation or a discharge operation by reciprocating the piston of the pump 13 in the arrow direction. This driving means 2 is controlled by the control means 4. The control contents of the driving means 2 and the pump 13 by the control means 4 are the same as those in FIG. In the embodiment shown in FIG. 4, the control means 4 controls the reciprocating motion of the piston of the pump 13 to control the suction operation and the discharge operation, and at the same time, the switching operation of the sample channel on the suction side and the discharge side is also automatic Is doing it. The sample gas sent from the pump 13 to the sample introduction path 6 passes through the dehumidifying filter 7 and the column 8 and is sent to the analyzer.
[0028]
In the sample introduction apparatus in the form of FIG. 4, the rotary valve 3 is not required and the control content by the driving means 2 is simplified as compared with that in FIG. 1, so that the cost of the entire apparatus can be reduced. In this type of sample introduction apparatus as well, the entire amount of sample gas required for measurement is sucked into the pump by a single suction operation, and the sample gas is introduced into the analyzer at a constant flow rate and a constant pressure by a discharge operation. It is preferable. Moreover, as a pump of the sample introduction device in FIG. 4, a pump of another form other than the pump 13 can be used.
[0029]
FIG. 5 is a view showing a modification of the pump used in the sample introduction method and apparatus of FIG. This pump 14 uses a bellows 14c instead of using a piston. Since the bellows 14c is used, there is no sliding part and the airtightness is good. The pump 14 is provided with a suction port and a discharge port, a check valve 14a is provided in the vicinity of the suction port, and a check valve 14b is provided in the vicinity of the discharge port. The check valve 14a is arranged to pass only the flow of the sample gas in the suction direction, and the check valve 14b is arranged to pass only the flow of the sample gas in the discharge direction.
[0030]
This pump 14 can be used in place of the pump 13 of FIG. The connection path 5 is connected to the check valve 14a on the suction port side of the pump 14, and the sample introduction path 6 is connected to the check valve 14b on the discharge port side. By causing the drive means 2 to reciprocate the right end of the bellows 14c of the pump 14 in the direction of the arrow, the pump 14 is caused to perform a suction operation or a discharge operation. The operations of the check valves 14a and 14b during the suction operation and the discharge operation are the same as those in FIG. In addition to the pumps 13 and 14, any pump having a similar function can be used as the pump of the sample introduction device in FIG. 4.
[0031]
As described above, according to the present invention, it is possible to introduce the sample gas as it is into the analyzer without diluting without using the carrier gas. Since the sample gas is not diluted, the analysis sensitivity of the analyzer can be improved. In addition, since no carrier gas is used, the cost of the carrier gas can be saved, and a carrier gas cylinder replacement operation or the like is not required, and the running cost for analysis can be reduced.
[0032]
In addition, since the sucked sample gas is pressurized and introduced into the analyzer, fluctuations in the introduction pressure of the sample gas can be suppressed, and the pressure can be held almost constant, enabling stable measurement by the analyzer. It becomes. Furthermore, since only one needle is required to connect to the sample tube, connection work can be simplified. Further, it is not necessary to use a double needle having a complicated structure and an expensive connection needle.
[0033]
And the sample gas can be automatically introduced into the analyzer while maintaining the connection between the sample tube and the connection needle without manually changing the connection destination of the connection needle. Air does not flow from the connecting needle and mix with the sample gas, so that the composition of the sample gas is not changed.
[0034]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained.
[0035]
Since the sample gas in the sample container is sucked by the pump, and the sucked sample gas is pressurized and discharged to the analyzer side, the carrier gas is not used. It becomes possible to introduce. Since the sample gas is not diluted, the analysis sensitivity of the analyzer can be improved. In addition, since no carrier gas is used, the cost of the carrier gas can be saved, and a carrier gas cylinder replacement operation or the like is not required, and the running cost for analysis can be reduced.
[0036]
In addition, since the sucked sample gas is pressurized and introduced into the analyzer, fluctuations in the introduction pressure of the sample gas can be suppressed, and the pressure can be held almost constant, enabling stable measurement by the analyzer. It becomes. Furthermore, since only one needle is required to connect to the sample container, the connection work can be simplified. Further, it is not necessary to use a double needle having a complicated structure and an expensive connection needle.
[0037]
And the sample gas can be automatically introduced into the analyzer while maintaining the connection between the sample tube and the connection needle without manually changing the connection destination of the connection needle. Air does not flow from the connecting needle and mix with the sample gas, so that the composition of the sample gas is not changed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a sample introduction method and apparatus according to the present invention.
FIG. 2 is a diagram illustrating an operation of the sample introduction device.
FIG. 3 is a diagram illustrating the operation of the sample introduction apparatus.
FIG. 4 is a diagram showing another embodiment of the sample introduction method and apparatus of the present invention.
FIG. 5 is a view showing a modified example of a pump used in the sample introduction device.
FIG. 6 is a diagram showing a conventional sample introduction method and apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Pump 2 ... Drive means 3 ... Rotary valve 4 ... Control means 5 ... Connection path 6 ... Sample introduction path 7 ... Dehumidification filter 8 ... Column 9 ... Sample tube 10 ... Cylinder 11 ... Carrier gas introduction path 12 ... Sample introduction path 13 ... pump 14 ... pump

Claims (6)

Pumps (1, 13, 14) connected to the sample container (9) and capable of changing the discharge destination to the sample introduction path (6) of the analyzer while the connection portion is attached to the sample container (9) ) By which a predetermined amount of the sample gas in the sample container (9) is sucked,
A sample introduction method in gas component analysis, comprising a procedure of discharging a predetermined amount of the sample gas sucked by the pump (1, 13, 14) to the analyzer side through the sample introduction path (6). A sample introduction method in gas component analysis according to claim 1,
The pump (1) is a piston / cylinder pump,
A sample introduction method in gas component analysis, comprising: a step of changing the discharge destination of the pump (1) to the sample introduction path (6) after the sample gas is sucked into the pump (1). Pumps (1, 13, 14) connected to the sample container (9) and capable of changing the discharge destination to the sample introduction path (6) of the analyzer while the connection portion is attached to the sample container (9) )When,
The pump (1, 13, 14) is controlled so that the sample gas in the sample container (9) is sucked into the pump (1), and then the sucked sample gas is moved to the sample introduction path (9) side. A sample introduction device in gas component analysis, comprising: a control means (4) for discharging the gas. A pump (1) for discharging the sucked sample gas after sucking a predetermined amount of the sample gas;
Switching means (3) for communicating the pump (1) with either the sample container (9) containing the sample gas or the sample introduction path (6) of the analyzer;
The pump (1) and the switching means (3) are controlled to cause the pump (1) and the sample container (9) to communicate with each other and cause the pump (1) to perform a suction operation. A sample introduction apparatus in gas component analysis, comprising: a control means (4) for communicating (1) and the sample introduction path (9) and causing the pump (1) to perform a discharge operation. A sample introduction device in gas component analysis according to claim 4,
The pump (1) is a piston / cylinder pump, which is a sample introduction device in gas component analysis. A sample introduction device in gas component analysis according to claim 5,
The pump (1) is a sample introduction device in gas component analysis in which the suction volume is set larger than the volume of the sample container (9).

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