JP2016200479A - Sample injection valve, continuous stream sample introduction-detection device having the valve, method for migration, method for manufacturing the sample, and method for analyzing the sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a sample and a method for analyzing a sample that can attain a high level of separation effects with a small amount of sample solution and can make a highly sensitive analysis free from influence or interruption of a matrix without performing a dilution operation or a pretreatment operation.SOLUTION: The sample injection valve includes: a sample loop 24 to be filled with a sample; a sample feeding path 22 capable of supplying the sample in the sample loop 24; a sample flow path 20 having a sample discharge path 26 capable of discharging the sample in the sample loop 24, a part of the sample flow path 20 being in contact with a liquid and made of a non-conductive material, and the sample flow path 20 having a pair of electrodes 28a, 28b.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a sample injection valve capable of separating and concentrating an analysis component and a matrix component in a sample solution, a continuous flow system sample introduction / detection device including the same, an electrophoresis method, a sample manufacturing method, and a sample analysis method.

  In the analysis of components in a sample solution, various continuous flow system sample introduction / detection devices such as flow injection, ion chromatography, liquid chromatography, etc. are used according to the analysis target component. Various detection devices have been selected for highly sensitive analysis. However, when various contaminant components are contained in the sample solution containing the analysis component, it is not always possible to perform a highly sensitive analysis. Contaminant components, so-called matrix components, are often unknown in their composition and concentration, such as environmental water or industrial wastewater represented by river water and seawater, and may have a plurality of contaminant component compositions. In many cases, the concentration is a high concentration of the% level. For this reason, when analyzing a sample containing a matrix component, it may be difficult to directly analyze the sample solution due to the influence of the matrix component. In particular, when the matrix component has a plurality of compositions as described above or has a high concentration of% level, analysis becomes extremely difficult.

  When analyzing such a sample, it is necessary to dilute the sample solution in advance and introduce it into the analyzer, or to perform some pretreatment operation in advance to remove the matrix component from the analyzed component and then introduce it into the analyzer There is. In these cases, the analysis sensitivity is lowered due to the dilution of the sample solution, or the analysis components are contaminated or lost in the pretreatment operation. As a result, there is a problem that the highly sensitive analysis cannot be performed. In addition, depending on the matrix component, there is a problem that the analysis itself cannot be performed due to interference. Therefore, development of a high-sensitivity analyzer and method for the target component in the sample containing the matrix component is desired to solve such problems. To deal with this problem, for example, in Non-Patent Document 1, an ion exchange membrane is used and the matrix component and the analysis ion component are separated by electrodialysis.

Shin-ichi Ohira, Kenta Kuhara, Mayu Kudo, Yuko Kodama, Purnendu K. Dasgupta, and Kei Toda. (2012), Electrodialytic Ion Isolation for Matrix Removal. Analytical Chemistry, 84, (12), 5421-5426.

  However, Non-Patent Document 1 has a problem that the separation apparatus is large and has a complicated structure, and requires a large amount of sample solution. In order to solve such problems, it is indispensable to develop a method in which the separation apparatus has a simple structure, is easy to operate, and can perform analysis with a small amount of sample solution.

  The present invention has been made in view of the above problems, and does not undergo dilution operation or pretreatment operation. A high separation effect can be obtained with a small amount of sample solution. As a result, there is no influence or interference by matrix components. It is an object of the present invention to provide a sample injection valve capable of performing highly sensitive analysis, a continuous flow system sample introduction / detection device including the same, an electrophoresis method, a sample manufacturing method, and a sample analysis method.

  As a result of intensive investigations to achieve the above object, the inventors of the present invention have found that in a sample injection valve, a sample loop for filling a sample, a sample supply path capable of supplying a sample to the sample loop, and the inside of the sample loop By providing a pair of electrodes in the sample flow path that has a sample discharge path that can discharge the sample, a high separation effect can be obtained with a small amount of sample solution without passing through dilution operation and pretreatment operation. The present inventors have found that a highly sensitive analysis without influence or interference by components can be performed, and the present invention has been achieved.

  That is, the present invention comprises a sample loop having a sample loop for filling a sample, a sample supply path capable of supplying a sample to the sample loop, and a sample discharge path capable of discharging the sample in the sample loop, The present invention relates to a sample injection valve in which a liquid contact portion of a sample channel is made of a non-conductive material, and a pair of electrodes are provided in the sample channel.

  In the present invention, the electrode is preferably provided so that at least a part of the electrode is exposed in the flow path of the sample.

  In addition, the present invention relates to a continuous flow system sample introduction / detection device characterized in that the sample injection valve is provided.

  In the present invention, the continuous flow system sample introduction / detection device is preferably at least one selected from flow injection, ion chromatography, and liquid chromatography.

  Furthermore, the present invention relates to an electrophoresis method characterized by applying a voltage from a direct current power source to an electrode of a sample injection valve.

  The present invention also relates to a method for manufacturing a sample, characterized in that a voltage from a DC power source is applied to an electrode of a sample injection valve.

  In the present invention, it is preferable to change the polarity of the voltage applied to the electrode.

  In the present invention, it is preferable that after the voltage application, contaminant components present in the sample in the sample loop are discharged as waste liquid.

  Furthermore, the present invention relates to a sample analysis method, characterized in that the sample obtained by the manufacturing method is analyzed using a continuous flow system sample introduction / detection device.

  As described above, according to the present invention, a high separation effect can be obtained with a small amount of sample solution without going through a dilution operation or a pretreatment operation. As a result, a highly sensitive analysis without influence or interference by the matrix is performed. It is possible to provide a sample injection valve, a continuous flow system sample introduction / detection device including the same, an electrophoresis method, a sample manufacturing method, and a sample analysis method.

FIG. 2 is a schematic view showing a sample injection valve 10 according to the first embodiment in which electrodes 28a and 28b are installed in a sample loop 24. It is the figure which showed an example of the shape of the electrodes 28a and 28b. It is the schematic which showed the sample injection valve 10 which concerns on this Embodiment 2 which installed electrode 28a, 28b out of the sample loop 24. FIG. FIG. 4 is a schematic view showing a sample injection valve 10 according to a third embodiment in which electrodes 28a and 28b are installed inside and outside the sample loop 24. It is the schematic which showed the continuous flow type | system | group sample introduction and detection apparatus 12 which concerns on this Embodiment 4 which installed the sample injection valve 10 which concerns on this Embodiment 1. FIG. It is the schematic of the continuous flow type anion analyzer 14 used in the Example. 2 is a chromatogram of anions measured in Comparative Example 1. FIG. 2 is an anion chromatogram measured in Example 1. FIG. 4 is a chromatogram of anions measured in Comparative Example 2. 2 is a chromatogram of anions measured in Example 2. FIG. 6 is a chromatogram of anions measured in Comparative Example 3. 2 is an anion chromatogram measured in Example 3. FIG.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

  The sample injection valve 10 according to the first embodiment is a sample introduction device to a sample detection device (not shown), and is a device capable of separating a matrix component in a sample solution from an analysis component and concentrating the analysis component. is there. As shown in FIG. 1, the sample injection valve 10 includes a valve body 11 that is a six-way valve having ports 1 to 6, a sample loop 24 that communicates ports 2 and 5, and a sample supply pipe connected to the port 4. 22 and a sample discharge pipe 26 connected to the port 3. A mobile phase introduction pipe 30 capable of introducing a mobile phase is connected to the port 1 of the valve body 11, and a mobile phase discharge pipe 32 capable of discharging the mobile phase is connected to the port 6.

  In the standby state of the sample injection valve 10 according to the first embodiment, the sample flows through the sample flow path 20 of the sample supply pipe 22 → port 4 → port 5 → sample loop 24 → port 2 → port 3 → sample discharge pipe 26. To do. When the valve is switched from this standby state, a flow path of mobile phase introduction pipe 30 → port 1 → port 2 → sample loop 24 → port 5 → port 6 → mobile phase discharge pipe 32 is formed and filled in sample loop 24. The sample solution that has been stored is introduced into the sample detector. In this embodiment, in addition to such a 6-way valve, a sample injection valve such as a 2-way valve, a 4-way valve, or an 8-way valve can be used.

  In the first embodiment, the flow path between the ports 2 and 3 forming the sample flow path 20, the flow path between the ports 4 and 5, the sample loop 24, the sample supply pipe 22, and the sample discharge pipe 26 are liquid contact portions. Is made of a non-conductive material. Specific examples of the non-conductive material include polymer materials such as plastics, and in particular, polytetrafluoroethylene (Teflon: registered trademark), polyether ether ketone (PEEK: registered trademark), etc. are preferably used. It is done.

  The sample supply pipe 22 can supply a sample solution to the sample loop 24 from a sample supply source (not shown). As the sample supply source, a microsyringe, a liquid feed pump, or the like used in a normal continuous flow system sample introduction / detection device can be used without particular limitation.

  The sample loop 24 can be filled with the sample solution supplied from the sample supply pipe 22. The sample filled in the sample loop 24 is introduced into the sample detection device by switching the valve of the valve body 11. The amount of the sample solution introduced into the sample detection device is determined by the inner diameter and length of the sample loop 24. The inner diameter and length of the sample loop 24 are not particularly limited, but considering the voltage application conditions described later, the inner diameter is preferably 0.1 to 3.0 mm, and the length is preferably 5 to 500 mm, and more preferably Has an inner diameter of 0.2 to 0.8 mm and a length of 200 to 350 mm.

  After the sample solution is introduced into the sample detection device through the mobile phase discharge tube 32, the sample discharge pipe 26 discharges unnecessary components remaining in the sample loop 24 or applies a voltage to the sample solution. Used to discharge the matrix components concentrated in

  The sample channel 20 is provided with a pair of electrodes 28a and 28b. A pair of electrodes 28a and 28b are used to apply a DC voltage from a DC power source. In the first embodiment, the electrodes 28a and 28b can be installed near the ports 2 and 5 of the sample loop 24 as shown in FIG. By applying a voltage from the DC power source to the electrodes 28a and 28b, the matrix component in the sample solution existing in the sample loop 24 can be migrated to either one of the electrodes. When the electrodes 28 a and 28 b are installed inside the sample loop 24 as in the first embodiment, the sample components can be separated inside the sample loop 24. In the first embodiment, by providing a pair of electrodes 28a and 28b in the sample channel 20, a voltage is applied to the sample solution, and the analysis components and matrix components in the sample solution are applied to the electrodes 28a and 28b by an electrophoretic action. By migrating in the vicinity, the matrix component can be separated from the analysis component, and the sample solution containing the concentrated analysis component can be introduced into the mobile phase through the mobile phase discharge pipe 32 and then separated and detected by the sample detection device.

  The electrodes 28a and 28b have a structure exposed to the liquid contact portion of the sample channel 20, and the shape and size of the electrode are not particularly determined. For example, as shown in FIG. A loop-shaped one that does not hinder the flow of the solution can be used. Moreover, as long as the material of the electrodes 28a and 28b for applying a DC voltage has a property of conducting electricity, any material can be used, but among them, a chemically inert material is preferable. It is particularly preferable to use a precious metal such as platinum or gold.

  In the first embodiment, the voltage is applied from a DC power source (not shown), and the concentration degree of the analysis component is determined mainly by the applied voltage and the application time. The applied voltage is preferably −5000 to +5000 V. If the applied voltage is out of this range, the generation of gas becomes remarkable, which causes a problem. The applied voltage is more preferably −2500 to + 2500V. The application time can be about 120 minutes at the maximum. However, if the application time is too long, the problem of bubble generation occurs, so about 30 to 40 minutes is most preferable. In the first embodiment, the ion component that migrates in the sample component can be changed by changing the polarity of the voltage applied to the electrodes 28a and 28b.

  As an example when a voltage is applied, for example, when an analysis component is migrated to the electrode 28a and a matrix component is migrated to the electrode 28b, by switching the valve of the valve body 11 for a certain period of time, among the sample solutions in the sample loop 24, Only the sample solution containing the analysis component concentrated in the vicinity of the electrode 28 a can be introduced into the mobile phase discharge pipe 32. After the introduction of only the sample solution containing the concentrated analysis component into the mobile phase discharge pipe 32, the valve of the valve body 11 is switched again, so that the concentrated matrix component that is no longer needed is contained in the sample loop 24. A part of the contained sample solution and mobile phase remains. These unnecessary components are pushed out when the next sample solution is filled, and can be discharged as waste liquid from the sample discharge pipe 26. In the first embodiment, which electrode the analysis component and the matrix component are migrated to is not particularly limited, and can be appropriately selected depending on the purpose. Therefore, the sample solution containing the concentrated matrix component is discharged from the sample discharge pipe 26 as waste liquid first, and then the sample solution containing the concentrated analysis component is introduced into the mobile phase discharge pipe 32 by switching the valve of the valve body 11. It is also possible to do.

  As shown in FIG. 3, the sample injection valve 10 according to the second embodiment is the same as that of the present embodiment except that the installation location of the electrode 28a is changed to the sample supply pipe 22 and the installation location of the electrode 28b is changed to the sample discharge pipe 26. This is a sample injection valve 10 similar to that of the first embodiment. As shown in FIG. 3, the electrodes 28 a and 28 b may be installed outside the sample loop 24 as long as they are in the sample flow path 20.

  The sample injection valve 10 according to the third embodiment is the same as the sample injection valve 10 according to the first embodiment except that the installation location of the electrode 28a is changed to the sample supply pipe 22 as shown in FIG. . As shown in FIG. 4, if the electrodes 28 a and 28 b are installed in the sample channel 20, only one of the electrodes can be installed in the sample supply pipe 22 (or the sample discharge pipe 26). May be installed.

  In the second and third embodiments, the analysis component is more reliably concentrated in the sample loop 24 by concentrating the cation or anion which is a matrix component outside the sample loop 24 by setting the charge application method. It is possible to measure with high sensitivity. For example, in the third embodiment, by concentrating the matrix component in the vicinity of the electrode 28a and the analytical component in the vicinity of the electrode 28b, only the sample solution containing the concentrated analytical component is introduced into the mobile phase discharge pipe 32 and then concentrated. The sample solution containing the matrix component thus made can be discharged from the sample discharge pipe 26 as a waste liquid. In the second and third embodiments, which electrode the analysis component and the matrix component are migrated to is not particularly limited, and can be appropriately selected according to the purpose.

  If the distance between the electrodes 28a and 28b exemplified in the first to third embodiments is too short, a short circuit occurs. If the distance is too long, the voltage per unit length is lowered, so that separation of matrix components and concentration of analysis components cannot be performed. Such a problem occurs. Therefore, the distance between the electrodes 28a and 28b is preferably 5 to 500 mm, and more preferably 200 to 350 mm.

  By using the sample injection valve 10 according to the first to third embodiments, no special pre-treatment that has so far required skill is required in the steps of concentration of analysis components in a sample solution and separation / removal of a large amount of matrix components. In addition, it is possible to remove matrix components and concentrate analysis components. Further, since the concentration / separation process is performed in a closed tube such as the sample channel 20, contamination of the analysis component from the experimental environment and loss during pretreatment can be eliminated.

  Next, the provision of the sample injection valve 10 according to Embodiments 1 to 3 in the continuous flow system sample introduction / detection device will be described. Examples of the continuous flow system sample introduction / detection device include flow injection, ion chromatography, and liquid chromatography.

  As an example, FIG. 5 shows a continuous flow system sample introduction / detection device 12 according to the fourth embodiment in which the sample injection valve 10 according to the first embodiment is installed. The installation position of the sample injection valve 10 can be installed at any position in the middle of the continuous flow system, and various installation methods other than the installation position shown in FIG. 5 can be considered. When the system sample introduction / detection device 12 is ion chromatography, it is preferably installed at any location in front of the detector 42 and the separation column 40 as illustrated in FIG.

  In the sample injection valve 10, after voltage application by the electrodes 28 a, 28 b, the sample solution containing the concentrated analysis components in the sample loop 24 is introduced into the mobile phase through the mobile phase discharge pipe 32, and from the separation column 40 and the detector 42. It detects with the sample detection apparatus comprised. The method of introducing the sample solution from the sample injection valve 10 into the continuous flow system may introduce all the sample solution in the sample loop 24 by controlling the switching timing of the sample injection valve 10, or the sample loop. A part of the sample solution in 24 may be introduced.

  The separation column 40 separates the sample solution supplied from the sample injection valve 10 for each target component. Specifically, the separation column 40 includes a filler for adsorbing the sample solution, and each component of the sample solution adsorbed on the filler is desorbed by the eluent. Each component separated by the separation column 40 is then sent to the detector 42. The detector 42 is a measuring device such as an electric conductivity detector, for example, and measures the electric conductivity of the components separated by the separation column 40. The detector 42 is not limited to a device that measures electrical conductivity.

  As described above, according to the present embodiment, it is possible to provide a sample injection valve capable of performing stable high-sensitivity and high-accuracy analysis and a continuous flow system sample introduction / detection device including the sample injection valve.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, these do not limit the objective of this invention.

[Comparative Example 1]
A sample injection valve 10 having a platinum electrode 28a on the sample loop 24 having an inner diameter of 0.5 mm and a length of 125 mm, and a platinum electrode 28b (interelectrode distance 425 mm) in the sample discharge pipe 26, a DC power supply 29, and an ion chromatograph device 46 are provided. The continuous flow system anion analyzer 14 was formed as shown in FIG. The sample loop 24 of the sample injection valve 10 is filled with a sample solution containing 500 ppb each of analytical anions (fluoride ions, chloride ions, bromide ions, nitrite ions, nitrate ions, phosphate ions, sulfate ions), and voltage is applied. The sample solution in the sample loop 24 was introduced into the mobile phase discharge pipe 32 without being detected, and each ion component was detected by the ion chromatograph device 46. The results are shown in FIG.

[Example 1]
The sample loop 24 of the sample injection valve 10 is filled with a sample solution containing 500 ppb each of the same type of analysis anions as in Comparative Example 1, and a voltage of +2500 V is applied for 30 minutes, the analysis component is in the vicinity of the electrode 28a, and the matrix component is in the vicinity of the electrode 28b. The analysis component and the matrix component were separated by electrophoresis. Thereafter, the valve of the valve body 11 is switched, and the sample solution containing the analytical component concentrated near the electrode 28a in the sample loop 24 is introduced into the mobile phase discharge pipe 32, and each ion component is detected by the ion chromatograph device 46. went. The results are shown in FIG.

  As shown in FIGS. 7 and 8, Example 1 to which a voltage was applied was able to increase the detection sensitivity by the ion chromatograph device 46 to 5 times that of Comparative Example 1 to which no voltage was applied.

[Comparative Example 2]
A sample injection valve 10 having a platinum electrode 28a on the sample loop 24 having an inner diameter of 0.5 mm and a length of 125 mm, and a platinum electrode 28b (interelectrode distance 425 mm) in the sample discharge pipe 26, a DC power supply 29, and an ion chromatograph device 46 are provided. The continuous flow system anion analyzer 14 was formed as shown in FIG. The sample loop 24 of the sample injection valve 10 is filled with the sample solution (0.5% sodium hydroxide aqueous solution), and the sample solution in the sample loop 24 is introduced into the mobile phase discharge pipe 32 without applying a voltage, and ion chromatography. The apparatus 46 detected each ion component. The results are shown in FIG.

[Example 2]
The sample loop 24 of the sample injection valve 10 is filled with the same sample solution as in Comparative Example 2, and a voltage of +2500 V is applied for 30 minutes to migrate the analysis component in the vicinity of the electrode 28a and the matrix component in the vicinity of the electrode 28b. Analytical components and matrix components were separated. Thereafter, the valve of the valve body 11 was switched, and the sample solution containing the analytical component concentrated near the electrode 28 a in the sample loop 24 was introduced into the mobile phase discharge pipe 32, and the ion component was detected by the ion chromatograph device 46. . The results are shown in FIG.

  As shown in FIGS. 9 and 10, in Comparative Example 2 in which no voltage was applied, the ion component could not be detected due to interference due to a high alkali concentration, but in Example 2 in which voltage was applied, the ion chromatograph device 46 performed ion detection. It became possible to recognize a clear peak of the component.

[Comparative Example 3]
A sample injection valve 10 having a platinum electrode 28a on the sample loop 24 having an inner diameter of 0.5 mm and a length of 125 mm, and a platinum electrode 28b (interelectrode distance 425 mm) in the sample discharge pipe 26, a DC power supply 29, and an ion chromatograph device 46 are provided. The continuous flow system anion analyzer 14 was formed as shown in FIG. The sample loop 24 of the sample injection valve 10 is filled with the sample solution (80% methanol solution), the sample solution in the sample loop 24 is introduced into the mobile phase discharge pipe 32 without applying a voltage, and each ion chromatograph device 46 is used. The ion component was detected. The results are shown in FIG.

[Example 3]
The sample loop 24 of the sample injection valve 10 is filled with the same sample solution as in Comparative Example 3 above, and a voltage of +2500 V is applied for 30 minutes to migrate the analysis component in the vicinity of the electrode 28a and the matrix component in the vicinity of the electrode 28b. Analytical components and matrix components were separated. Thereafter, the valve of the valve body 11 was switched, and the sample solution containing the analytical component concentrated near the electrode 28 a in the sample loop 24 was introduced into the mobile phase discharge pipe 32, and the ion component was detected by the ion chromatograph device 46. . The results are shown in FIG.

  As shown in FIGS. 11 and 12, by applying a voltage as in Example 3, the detection sensitivity of the ion chromatograph device 46 can be increased even in alcohol as an organic solvent.

1 port 2 port 3 port 4 port 5 port 6 port 10 sample injection valve 11 valve body 12 continuous flow system sample introduction / detection device 14 continuous flow system anion analyzer 20 sample flow path 22 sample supply tube 24 sample loop 26 sample discharge Tube 28a Electrode 28b Electrode 29 DC power supply 30 Mobile phase introduction tube 32 Mobile phase discharge tube 40 Separation column 42 Detector 44 Recording unit 46 Ion chromatograph device

Claims (9)

A sample loop including a sample loop for filling a sample, a sample supply path capable of supplying a sample to the sample loop, and a sample discharge path capable of discharging the sample in the sample loop, and at least liquid contact of the sample flow path A sample injection valve part made of non-conductive material,
A sample injection valve, wherein a pair of electrodes is provided in the sample flow path.   The sample injection valve according to claim 1, wherein at least a part of the electrode is provided so as to be exposed in the flow path of the sample.   A continuous flow system sample introduction / detection device comprising the sample injection valve according to claim 1.   4. The continuous flow system sample introduction / detection device according to claim 3, wherein the continuous flow system sample introduction / detection device is at least one selected from flow injection, ion chromatography, and liquid chromatography.   3. A migration method comprising applying a voltage from a direct current power source to the electrode of the sample injection valve according to claim 1 or 2.   A method for producing a sample, comprising applying a voltage from a DC power source to the electrode of the sample injection valve according to claim 1.   The method for producing a sample according to claim 6, wherein the polarity of the voltage applied to the electrode is changed.   The method for producing a sample according to claim 6 or 7, wherein after the voltage application, a contaminant component present in the sample in the sample loop is discharged as a waste liquid. 9. A sample analysis method comprising: analyzing a sample obtained by the production method according to claim 6 using a continuous flow system sample introduction / detection device.

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