JP2013205324A - Head space sample introduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head space sample introduction device that can avoid lengthening of cycle time of analysis, clean internal and external surfaces of a needle reliably, and perform analysis accurately in a short time even for analysis of a highly concentrated sample.SOLUTION: A head space sample introduction device includes a cleaning mechanism that cleans internal and external surfaces of a needle 1 for collecting sample gas. The cleaning mechanism includes: a cleaning passage formation member (elevation member 3a) for tightly inserting the tip end of the needle 1 thereinto by a predetermined length by moving towards the needle 1; cleaning fluid supply means (a cleaning fluid supply source 36, a passage 35 and a stop valve SV3) for pressurizing and supplying a cleaning fluid in the cleaning passage formation member to allow the same to flow into the needle 1; and a discharging passage (a passage 20, a six-way valve 21, a measuring pipe 23, a passage 24, a stop valve SV1 and a discharge passage 27) for discharging cleaning fluid. The cleaning mechanism is allowed to operate every time a sample container is replaced.

Description

  The present invention relates to an introduction device for introducing a sample gas into a gas analyzer such as a gas chromatograph, and more particularly to a headspace sample introduction device.

  One analysis method in gas chromatography is headspace analysis. In this headspace analysis method, a liquid or solid sample is sealed in a sample container with a septum lid while leaving a space in the upper part. Gas (sample gas) is collected and introduced into a gas chromatograph. This analysis method is suitable for the measurement of components having a relatively low boiling point, such as measurement of flavors in foods and measurement of volatile organic compounds in water.

  The headspace sample introduction device that automatically performs the above headspace analysis method is also referred to as a headspace autosampler, which sequentially moves a plurality of sample containers to a sample gas sampling position, and samples the needle at the sample gas sampling position. The structure which stabs in a container and extract | collects the gas of upper space is used abundantly.

3A to 3D schematically illustrate the configuration of the sample gas sampling position and the gas sampling procedure in the conventional headspace gas introduction device.
A thin tubular needle 51 is arranged at the sample gas sampling position, and this needle 51 communicates with a flow path including a loop-shaped metering tube communicating with a column of the gas chromatograph through a valve. The sample container 52 is heated for a set time at a set temperature, and then positioned on the lifting member 53a of the lifting mechanism 53 disposed below the needle 51 (FIG. 3A).

  The top of the sample container 52 is sealed with a septum 52a made of a flexible member such as silicon rubber, and the elevating member 53a is raised by driving the elevating mechanism 53, so that the needle 51 is attached to the septum 52a at the top of the sample container 52. And the tip of the needle 51 is inserted into the upper space of the sample container 52 (FIG. 3B). In this state, by driving a valve group in the apparatus flow path, a gas for pressurization is introduced into the sample container 52 through the needle 51, the pressure in the container is increased to be higher than the atmospheric pressure, and the valve is again operated. The sample gas in the upper space of the sample container 52 is collected through the needle 51 by driving the group.

  After the sample gas is collected, the elevating member 53a of the elevating mechanism 53 is lowered to the original position (FIG. 3C), and the sample container 52 is removed from the elevating member 53a, and enters the needle 51 through the apparatus channel. The cleaning gas is flowed, and the sample gas in the needle 51 is washed away (FIG. 3D). As the cleaning gas, the same gas as the pressurizing gas described above is used, and in particular, helium gas is often used (see, for example, Patent Document 1).

  By repeating the above operation, the plurality of sample containers 52 are sequentially transported to the sample gas sampling position and are sequentially subjected to analysis.

JP 2012-018095 A

  By the way, the headspace sample introduction device collects the sample gas by piercing the needle into the upper space of the sample container as described above, and the needle is introduced until the next sample container is transported to the sample gas collection position. The inside of the sampling channel including the inner surface is cleaned using a cleaning gas, but when collecting a high-concentration sample, the sample adheres not only to the inner surface but also to the surface (outer surface) of the needle. For this reason, there is a problem in that the adhering component cannot be removed by the next measurement of the sample, which may affect the next measurement result.

  As a countermeasure against this problem, in a conventional sample introduction apparatus, a sample container filled with water is prepared to clean the surface of the needle, and the sample container is set in an elevating mechanism to perform the above-described sample introduction operation. There is a problem that the cycle time of analysis becomes longer by the amount of operation.

  The present invention has been made in view of such a situation, and can particularly clean the inner surface and the surface of the needle without prolonging the cycle time of the analysis, so that it is short even when analyzing a high-concentration sample. An object of the present invention is to provide a headspace sample introduction device that can perform accurate analysis in time.

  In order to solve the above-described problems, the head space sample introduction device of the present invention penetrates the sealing member into the upper space in the sample container whose top is sealed by a sealing member made of a flexible member, and passes through the needle. In the head space sample introduction device, the sample gas in the upper space is collected and sent to the analyzer, and the sampling and sending operation of the gas is executed by sequentially replacing the sample containers. A cleaning mechanism that cleans the needle with a fluid, and the cleaning mechanism moves toward the needle so that the tip of the needle is closely fitted by a predetermined dimension, and the cleaning channel The cleaning member is provided with a cleaning fluid supply means for pressurizing and supplying a cleaning fluid to the forming member and flowing into the needle, and a discharge channel for discharging the cleaning fluid. Cleaning mechanism is characterized by being configured to operate automatically after the completion of the collection and delivery of the sample gas from one sample container (claim 1).

  Here, in the present invention, a sample container is mounted below the needle, and an elevating member that is moved up and down by an elevating mechanism is disposed. A flow path for a cleaning fluid is formed on the elevating member, The end surface is provided with a seal mechanism in which the needle is tightly fitted by the ascending / descending member and enters the flow path, and a cleaning fluid is pressurized and supplied to the flow path. A configuration (Claim 2) including a cleaning fluid supply unit that flows into the needle and a discharge channel that discharges the cleaning fluid that flows into the needle can be suitably employed.

  The present invention provides a cleaning mechanism for simultaneously cleaning the inner surface and the surface of the needle, and the cleaning mechanism is used to collect sample gas from one sample container and then collect sample gas from the next sample container. The problem is solved by operating automatically.

  That is, when the tip of the needle is closely fitted by a predetermined size and the cleaning fluid is supplied into the needle, the needle is cleaned together with the inner surface together with the surface of the tip of the predetermined size. By executing this cleaning operation when sample gas has been collected from one sample container, the inner surface and the surface of the needle can be cleaned without extending the analysis time especially for cleaning.

  Further, the invention according to claim 2 is a configuration applicable to an apparatus including a sample container lifting mechanism at a sample gas sampling position, in which a needle is fitted into a lifting member that moves up and down by placing a sample container. It is used as a member for supplying the cleaning fluid under pressure. That is, a flow path for the cleaning fluid is provided in the elevating member, and a seal mechanism in which the needle is closely fitted when the elevating member is raised is provided at the top of the elevating member. A cleaning fluid is supplied inside. Thereby, the inner surface and the surface of the needle can be cleaned at a time, and there is an advantage that a special member and a moving mechanism for cleaning the needle are not required.

  According to the present invention, by supplying a cleaning fluid under pressure to the cleaning flow channel in a state where a predetermined dimension of the tip of the needle for collecting the sample gas is closely fitted in the cleaning flow channel, The inner surface and the surface of the sample are cleaned at once, and the operation is performed every time sampling of the sample gas from one sample container is completed, so even when measuring a high concentration sample, the components of the sample before adhering to the needle The sample can be transferred to the next measurement after it has been removed immediately after the sample is collected, and the needle is washed by filling the sample container with water and performing the sample collection operation. In addition, the cleaning operation does not increase the cycle time of the analysis, and the analysis time as a whole can be shortened.

  Further, as in the invention according to claim 2, the cleaning channel is formed in the lifting member of the lifting mechanism that lifts and lowers the sample container with respect to the needle, and the needle is tightly connected to the cleaning channel by the lifting member. By adopting a configuration in which the cleaning fluid is pressurized and supplied, it is not necessary to separately provide a flow path forming member, and it is possible to avoid complication of the apparatus configuration due to the addition of the cleaning mechanism.

The schematic diagram showing the structure of the sample gas sampling position in embodiment of this invention, and its operation | movement procedure. The figure which shows the state after switching of the flow-path structure of the head space sample introduction apparatus in embodiment of this invention, and the internal flow-path position of a six-way valve. The schematic diagram showing the structure of the sample gas sampling position in the conventional head space sample introduction apparatus, and its operation | movement procedure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A to 1E are a schematic configuration diagram of a sample gas sampling position and an operation procedure thereof in the embodiment of the present invention, and FIG. 2A is a diagram of the entire headspace sample introduction apparatus. It is a flow-path block diagram, The figure (B) is a figure which shows the state after switching the position of the internal flow path of the six-way valve 21. FIG.

First, the flow path configuration of the head space sample introduction device according to the embodiment of the present invention will be described with reference to FIG.
In FIG. 2, reference numeral 1 denotes a thin tubular needle, and the thin tube of the needle 1 is connected to a port a of the hexagonal valve 21 through a flow path 20. The port b of the hexagonal valve 21 communicates with one end of a loop-shaped measuring tube 23 via a flow path 22, and the other end of the measuring pipe 23 is connected to the port e of the hexagonal valve 21 via a flow path 24. Further, the port f of the hexagonal valve 21 communicates with the stop valve SV1 through the branch pipes 25 and 26, and the stop valve SV1 communicates with the exhaust passage 27. Similarly, the port f is also connected to the stop valve SV2 via the branch pipe 25, and the stop valve SV2 is connected to the pressurizing flow path 30 connected to the pressure adjusting device 29. The port c of the hexagonal valve 21 communicates with the gas chromatograph column 32 via the flow path 31, and the port d communicates with the flow rate adjustment device 34 via the flow path 33, and the carrier gas source ( (Not shown). Further, although a part is omitted in FIG. 2, a flow path 35 communicating with a cleaning flow path 3c formed in the elevating member 3a shown below is provided, and this flow path 35 is a stop valve SV3. To the cleaning fluid supply source 36.

  The six-way valve 21 in FIG. 2A operates so as to switch between the load position shown in FIG. 2 and the injection position shown in FIG.

  A sample gas collection position is below the needle 1 in FIG. 2, and a sample gas collection operation is performed below the needle 1 with a sample container held at a predetermined temperature for a predetermined time. In addition, although illustration is abbreviate | omitted, the heat retention mechanism of the sample container is also provided in this sample gas collection position, and the heat retention of the sample container is continued.

  Next, referring to FIG. 1, the apparatus configuration at the sample gas sampling position will be described. An elevating mechanism 3 made of, for example, a rack and pinion mechanism is provided at the sample gas collection position, and this elevating mechanism 3 is formed on an elevating member 3a for elevating and lowering the sample container 2 and on a side surface of the elevating member 3a. A pinion gear 3b that meshes with a rack (not shown) is mainly used. The sample container 2 from which the sample gas is to be collected is sequentially placed on the elevating member 3a and used for collecting the sample gas.

  The elevating member 3a is formed with a cleaning channel 3c along the center line thereof, and the cleaning channel 3c is formed so as to penetrate the elevating member 3a up and down, and the lower end side thereof is described above. It communicates with the flow path 35 and is connected to a cleaning fluid supply source via a stop valve SV3. The upper end side of the cleaning channel 3c opens toward the upper end surface of the elevating member 3a, and a heat-resistant O-ring 3d is attached to the opening.

  The sample container 2 is the same as the conventional one, and has a structure that is hermetically sealed by covering the top of the container body with a septum 2a made of a flexible member such as silicon rubber.

  The operation of the embodiment of the present invention having the above configuration will be described with reference to FIGS.

  First, the sample container 2 kept at a constant temperature for a certain period of time is placed on the elevating member 3a at the sample gas collection position as shown in FIG. 1A in order to collect the sample gas containing the sample components volatilized in the upper space. Placed in. At this time, the six-way valve 21 is at the load position shown in FIG. 2A, and the stop valves SV1, SV2, and SV3 are all closed.

  Next, as shown in FIG. 1B, the elevating mechanism 3 is driven to raise the elevating member 3a. As a result, the needle 1 pierces the septum 2 a at the top of the sample container 2, and a predetermined tip end of the needle 1 is inserted into the upper space of the sample container 2. At this time, the hexagonal valve 21 maintains the load position shown in FIG. 2A and opens the stop valve SV2 in this state, so that the pressure gas from the pressure adjusting device 29 passes through the pressurizing passage 30 and the needle through the metering pipe 23. 1 flows into the sample container 2 and pressurizes the sample container 2. Next, the stop valve SV2 is closed and the stop valve SV1 is opened, whereby the sample gas in the sample container 2 flows into the exhaust passage 27 through the measuring tube 23. Thereafter, the stop valve SV1 is closed and the hexagonal valve 21 is switched to the injection position shown in FIG. 2B, so that the sample gas in the measuring tube 21 is supplied to the column 32 of the gas chromatograph by the gas supplied from the pressure adjusting device 29. This completes the sampling of the sample gas.

  After the sampling of the sample gas is completed, the lifting mechanism 3 is driven as shown in FIG. 1C to lower the lifting member 3a, and then the sample container 2 is moved to the lifting member 3a as shown in FIG. 1D. While removing (returning) from above, the six-way valve 21 is switched to the original load position in the flow path configuration of FIG.

  Next, the elevating mechanism 3 is driven to raise the elevating member 3a. This rising amount is larger than the rising amount at the time of sampling the sample gas, and as shown in FIG. 1 (E), the predetermined dimension of the tip of the needle 1 is fitted into the cleaning channel 3c formed in the lifting member 3a. Raise to state. At this time, the outer peripheral surface of the needle 1 is in close contact with the inside of the heat-resistant O-ring 3d provided at the top of the elevating member 3a, and the upper end opening of the cleaning channel 3c is sealed by the needle 1 and the heat-resistant O-ring 3d. It will be stopped.

  In this state, the stop valve SV3 is opened and the stop valve SV1 is opened. As a result, the cleaning fluid is pressurized and supplied from the cleaning fluid supply source 36 to the cleaning flow path 3c in the elevating member 3a via the stop valve SV1 and the cleaning flow path 35. It flows into the inside from the tip, and the exhaust fluid flow path 20, the port a of the hexagonal valve 21, the port b flow path 22, the measuring pipe 23, the flow path 24, and the minute periods 25 and 26, and the exhaust flow path 27 Discharged from.

  With the above operation, the inner surface of the needle 1 and the inside of each flow path including the above-described measuring tube 23 and the like are cleaned with the cleaning fluid, and at the same time, the surface of the needle 1 is pressurized in the cleaning flow path 3c. The exposed cleaning fluid is exposed to cleaning. Therefore, both the inner surface and the surface of the needle 1 are cleaned immediately after sampling the sample gas. In the meantime, since the collected sample gas has been analyzed, the cleaning of the inner surface and the surface of the needle 1 is completed before the next sample container is transported to the sample gas sampling position. The accompanying cycle time is not extended.

  Here, the cleaning fluid is not particularly limited and may be either a gas or a liquid. For example, helium gas is used for the gas, and pure water is used for the liquid. Can be used.

  Moreover, in the above embodiment, although the example which forms the flow path 3c for washing | cleaning in the raising / lowering member 3a of the raising / lowering mechanism 3 and inserts the needle 1 there was shown, this invention is not limited to the structure, A cleaning flow path forming member may be provided separately from the elevating member 3a, and a mechanism for moving the cleaning flow path forming member so that the tip of the needle is fitted may be separately provided. However, by adopting the configuration of the above-described embodiment in which the cleaning channel forming member is shared with the lifting member 3 a of the lifting mechanism 3 and the needle 1 is inserted into the cleaning channel 3 c by driving the lifting mechanism 3. There is an advantage that the apparatus configuration can be simplified.

DESCRIPTION OF SYMBOLS 1 Needle 2 Sample container 2a Septum 3 Elevating mechanism 3a Elevating member 3b Pinion gear 3c Cleaning flow path 3d Heat-resistant O-ring 20, 22, 24, 31, 33 Flow path 21 Hexagonal valve 23 Measuring pipe 25, 26 Branch pipe 27 Exhaust flow Channel 29 Pressure regulator 32 Column 34 Flow rate regulator 35 Cleaning channel SV1, SV2, SV3 Stop valve

Claims (2)

A needle is inserted through the sealing member into the upper space in the sample container whose top is sealed by a sealing member made of a flexible member, and the sample gas in the upper space is collected and sent to the analyzer. In addition, in the headspace sample introduction apparatus that performs the sampling and delivery operation of the gas by sequentially exchanging the sample containers,
A cleaning mechanism for cleaning a surface and an inner surface of the needle with a fluid, and the cleaning mechanism includes a cleaning flow path forming member that fits the tip of the needle densely by a predetermined dimension by moving toward the needle. A cleaning fluid supply means for pressurizing and supplying a cleaning fluid to the cleaning channel forming member and flowing into the needle, and a discharge channel for discharging the cleaning fluid. The head space sample introduction device, wherein the cleaning mechanism is configured to automatically operate after completion of collection and delivery of the sample gas from one sample container. An elevating member mounted with a sample container and elevating and lowering by an elevating mechanism is disposed below the needle. A flow path for a cleaning fluid is formed in the elevating member, and the elevating member is raised at the upper end. And a cleaning fluid supply means for pressurizing and supplying a cleaning fluid to the flow path and flowing into the needle. The headspace sample introduction device according to claim 1, further comprising a discharge channel for discharging the cleaning fluid that has flowed into the needle.

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