JP2007333487A - Gas analysis unit, gas analyzer and gas analysis method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a potentiometric sensor type gas analysis unit having a practical life while utilizing a miniaturizing technology; a gas analyzer; and a gas analysis method. <P>SOLUTION: The gas analysis unit includes a reaction liquid passage 10 having a concentration part 12, and a sample gas passage 20 having a concentration part 22. In the concentration parts 12 and 22, a reaction liquid is made to contact to and react with a sample gas. A detection electrode 31 and a detection electrode 41 generating potential according to the nature of the reaction liquid are arranged to contact the reaction liquid on the upstream side and the downstream side of the concentration part 12, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a gas analysis unit, a gas analyzer, and a gas analysis method. More specifically, the present invention relates to a potentiometric sensor type gas analysis unit, a gas analyzer, and a gas analysis method that have a practical life while utilizing a micro technology.

Gas analysis by absorbing a sample gas into a reaction solution and observing changes in the reaction solution has been performed for a long time. In this case, the change of the reaction solution is widely observed using a potentiometric sensor that measures the potential according to the properties of the reaction solution.
The potentiometric sensor is generally composed of a detection electrode that generates a potential corresponding to the properties of the reaction liquid and a reference electrode that serves as a potential reference, and is usually disposed downstream of the sample gas absorption portion of the reaction liquid flow. . As the reference electrode, a silver / silver chloride electrode is generally used.

  However, depending on the type of gas to be measured, it is necessary to avoid using a silver / silver chloride electrode, and a method that does not use a reference electrode has been devised. For example, in Patent Document 1, in a hydrogen chloride concentration meter, detection electrodes are arranged on both the upstream side and the downstream side of a sample gas absorption portion of a reaction liquid flow, and a reference electrode is interposed between both detection electrodes via a liquid junction. By providing a cell chamber with a built-in, a potential difference between both detection electrodes is obtained without using a reference electrode (Patent Document 1).

On the other hand, microanalyzed analyzers (μ-TAS; called Micro Total Analytical System, Lab on a chip, etc.) have spread to various analysis fields in recent years.
When gas analysis is performed with μ-TAS, the reaction liquid after absorbing the sample gas is observed using a thermal lens microscope as a detector (Non-Patent Document 1).

However, when a thermal lens microscope is used as a detector, the entire analyzer is increased in size and cost. Therefore, in order to obtain a small and inexpensive product, there is a demand for a minute potentiometric sensor that can be used for μ-TAS. Particularly difficult in miniaturizing a potentiometric sensor is miniaturization of a reference electrode.
As reference electrodes applicable to μ-TAS, Hiroaki Suzuki et al. of the University of Tsukuba, on a glass substrate, a gold skeleton pattern, a silver thin film pattern, a polyimide layer having a slit for forming silver chloride, an ENT layer, an electrolyte A silver / silver chloride electrode in which layers and silicone rubber are sequentially laminated has been experimentally produced (Non-patent Document 2).
JP-A-3-148059 “1. Basic study of micro chemical analysis chip using gas-liquid reaction”, Chemical Sensors, 2003, Volume 19 Supplement B, p1-3 University of Tsukuba, Graduate School of Mathematical Sciences, Hiroaki Suzuki Laboratory, “Miniaturization of Liquid / Silver Chlorine Reference Electrode with Liquid Junction and Longer Life”, [Search May 16, 2006], Internet <URL: http: / /www.ims.tsukuba.ac.jp/~hsuzuki_lab/research/agcl/agcl.html>

However, the reference electrode of Non-Patent Document 2 has a very thin silver chloride layer as a result of miniaturization, and the silver chloride film is lost in a short time due to the elution of silver chloride into the reaction solution. The endurance life cannot be obtained. That is, as long as silver chloride having a large solubility product is used, it has been difficult to achieve both miniaturization of the reference electrode and longer life.
If only the use of the silver / silver chloride electrode is avoided, it is conceivable to construct a measurement system as in Patent Document 1. However, in this case, a cell chamber separated by a liquid junction has to be provided, and it is difficult to miniaturize.
The present invention has been made in view of the above circumstances, and provides a potentiometric sensor type gas analysis unit, a gas analyzer, and a gas analysis method that have a practical life while utilizing a micro technology. This is the issue.

  As a result of intensive studies by the present inventors in order to achieve the above-mentioned problems, if the analysis unit is micronized, the potential difference therebetween can be directly measured without interposing a cell chamber or the like containing a reference electrode therebetween. The inventors have found that they can be detected and have arrived at the present invention below.

That is, the present invention employs the following configuration.
[1] a reaction liquid channel through which the reaction liquid flows;
The reaction liquid channel includes a first detection electrode and a second detection electrode sequentially provided from the upstream side so as to come into contact with the reaction liquid in the reaction liquid channel, and the reaction liquid channel includes the first detection electrode and the second detection electrode. In between, the reaction solution has a reaction part that reacts with the sample gas,
The first detection electrode generates a potential according to the properties of the reaction solution on the upstream side of the reaction unit,
The gas detection unit, wherein the second detection electrode generates a potential corresponding to the property of the reaction solution on the downstream side of the reaction section.

[2] Furthermore, a sample gas flow path through which the sample gas flows is provided,
The gas analysis unit according to [1], wherein the reaction portion of the reaction liquid channel is adjacent to the sample gas channel in a state in which the fluid inside can contact each other.
[3] Furthermore, a gas-liquid separator is provided,
The gas analysis unit according to [1], wherein a reaction part of the reaction liquid channel is in contact with a sample gas through the gas-liquid separator.
[4] The gas analysis unit according to any one of [1] to [3], wherein a maximum depth of a portion of the reaction liquid channel where the first detection electrode and the second detection electrode are provided is 1 to 500 μm. .
[5] A gas analyzer comprising the gas analysis unit according to any one of [1] to [4] and an analyzer main body that detects a potential difference between the first detection electrode and the second detection electrode.
[6] A gas analysis method for analyzing the sample gas by measuring a potential difference between the first detection electrode and the second detection electrode of the gas analysis unit according to any one of [1] to [4]. The gas analysis method is characterized in that the reaction solution flow rate in the reaction solution channel is 0.01 to 1000 μL / min.
Gas analyzing method according to [7] The ionic strength of the reaction solution is ¹⁰ -7 to 10 ⁰ [6].

  According to the present invention, it is possible to provide a potentiometric sensor type gas analysis unit, a gas analyzer, and a gas analysis method that have a practical life while utilizing micro technology.

[First Embodiment]
FIG. 1 is a plan view showing a first embodiment of the present invention, FIG. 1 (a) is an overall view, and FIGS. 1 (b) to 1 (d) are main part enlarged views.
As shown in FIG. 1, the gas analysis unit of this embodiment includes a reaction liquid channel 10 and a sample gas flow path 20 provided on the substrate 1, and a detector 30 provided in contact with the reaction liquid flow path 10. 40.

As a material of the substrate 1, for example, silicon, resin, glass, quartz or the like can be used. Of these materials, glass has high transparency, and is suitable for optical analysis using this gas analysis unit. In particular, Pyrex (registered trademark) glass is preferable because of its high heat resistance and chemical resistance.
The substrate 1 may be composed of a single material or a combination of a plurality of materials. For example, a glass plate can be bonded to a silicon plate on which the reaction liquid channel 10 and the sample gas channel 20 are formed by etching or the like to form a substrate. Although the board | substrate 1 is made into flat form, there is no limitation in particular in a shape.

The reaction liquid channel 10 is composed of an introduction part 11, a collecting part 12 and an outflow part 13 from the upstream side (left side in the figure), and the sample gas flow path 20 is introduced from the upstream side (left side in the figure). It consists of a part 22 and an outflow part 23.
The collecting portion 12 of the reaction liquid channel 10 is adjacent to the collecting portion 22 of the sample gas flow channel 20 so that the fluid inside can be in contact with each other, so that the sample gas can be absorbed into the reaction solution. Yes. That is, in the present embodiment, the collecting portion 12 is a reaction portion where the reaction solution reacts with the sample gas.

At the upstream end of the introduction part 11 of the reaction liquid channel 10, a reaction liquid introduction port 10 a that communicates with the outside of the substrate 1 and into which the reaction liquid is introduced is provided. Further, a reaction liquid outlet 10b that communicates with the outside of the substrate 1 and through which the reaction liquid flows out is provided at the downstream end of the outflow portion 13 of the reaction liquid flow path 10. A sample gas introduction port 20 a that communicates with the outside of the substrate 1 and into which the sample gas is introduced is provided at the upstream end of the introduction portion 21. A sample gas outlet 20b that communicates with the outside of the substrate 1 and through which the sample gas flows out is provided at the downstream end of the outflow portion 23 of the sample gas flow path 20.

The collecting portion 12 of the reaction liquid flow channel 10 and the collecting portion 22 of the sample gas flow channel 20 will be described in more detail with reference to FIGS. 1B to 1D and FIG.
FIG. 1B is a partially enlarged plan view in the vicinity of the boundary between the introduction part 11 and the collection part 12 of the reaction liquid flow path 10 (the boundary between the introduction part 21 and the collection part 22 of the sample gas flow path 20). FIG. 1C is a partially enlarged plan view of the collecting portion 12 and the collecting portion 22 of each of the reaction liquid channel 10 and the sample gas channel 20. FIG. 1D is a partially enlarged plan view in the vicinity of the boundary between the collecting portion 12 and the outflow portion 13 of the reaction liquid channel 10 (the boundary between the collecting portion 22 and the outflow portion 23 of the sample gas flow channel 20). .
2 is a cross-sectional view taken along the line II-II of FIG. 1C (enlarged cross-sectional views of the collecting portion 12 and the collecting portion 22 of the reaction liquid channel 10 and the sample gas channel 20).

The depth d2 of the collecting portion 12 of the reaction liquid channel 10 is shallower (smaller) than the depth d1 of the collecting portion 22 of the sample gas channel 20. Further, the width w2 of the collective portion 12 is narrower (smaller) than the width w1 of the collective portion 22. As a result, the cross-sectional area of the collecting portion 12 of the reaction liquid channel 10 is narrower (smaller) than the cross-sectional area of the collecting portion 22 of the sample gas flow channel 20.
The depth d1 is preferably more than 50 μm, and the width w1 is preferably around (d1 × 2 + 10) μm. The depth d2 is preferably 50 μm or less, and the width w2 is preferably around (d2 × 2 + 10) μm. The ratio between the depth d1 and the depth d2 is preferably around 3: 1.
In addition, the depth here is the maximum depth in the cross section and the width is the maximum width in the cross section as shown in the figure, and the same applies to the following.

  In the present embodiment, the liquid reaction liquid and the gas sample gas are in direct contact with each other between the collecting portion 12 and the collecting portion 22 in a laminar flow state, and the components in the sample gas are reacted at the gas-liquid interface. Migrate in. Therefore, it is possible to react the components in the sample gas and the components in the reaction solution without using a diaphragm.

It is preferable that part or all of the inner surface of the reaction liquid channel 10 of the substrate 1 is lyophilic. In particular, it is preferable that the gathering portion 12 is lyophilic. Here, the lyophilic means that it is lyophilic with respect to the reaction liquid introduced from the introduction part 11 of the reaction liquid flow path 10, and is hydrophilic when the reaction liquid is aqueous. This means that when the reaction solution is oily, it is lipophilic.
On the other hand, it is preferable that part or all of the inner surface of the sample gas flow path 20 of the substrate 1 has low lyophilicity. In particular, it is preferable that the portion of the collecting portion 22 is low lyophilic.
As means for making hydrophilic and lipophilic, known means such as chemical treatment, plasma treatment, and surface roughening treatment can be appropriately used.

In the present embodiment, after the reaction solution and the sample gas come into contact with each other in the collecting portion 12 and the collecting portion 22, the reaction solution flows into the outflow portion 13 of the reaction solution flow channel 10, and the sample gas flows into the outflow portion 23 of the sample gas flow channel 20. Each is separated. Thus, in order for the two fluids to be separated again, it is necessary to maintain a state in which the gas-liquid interface is maintained between the collecting portion 12 and the collecting portion 22 to some extent, that is, a laminar flow state.
In order to achieve this laminar flow state, both the reaction liquid introduced from the reaction liquid introduction port 10a and the sample gas introduced from the sample gas introduction port 20a need to have a pressure of a certain level or more. And in order to ensure this pressure, it is necessary to make both flow volume more than fixed.
The flow rate necessary to achieve the laminar flow state depends on the cross-sectional area of the flow path. For example, when the depth d1 is 90 μm, the width w1 is 190 μm, the depth d2 is 60 μm, and the width w2 is 60 μm, When an experiment was conducted using a phenolphthalein solution and air, it was confirmed that a good interface state was obtained under the following conditions.
That is, when the flow rate of the reaction solution (phenolphthalein solution) is 1 μL / min, the flow rate of the sample gas (air) is 0.5 to 2.5 mL / min, and the flow rate of the sample gas is 1 mL / min, When the flow rate of the reaction solution was 0.1 to 5 μL / min, good interface states were obtained.

The detector 30 has a detection electrode 31 that generates a potential according to the properties of the reaction solution, and a terminal 32 connected to the detection electrode 31. The detector 40 includes a detection electrode 41 that generates a potential according to the properties of the reaction solution, and a terminal 42 connected to the detection electrode 41.
As the detection electrode 31 and the detection electrode 41, for example, an iridium oxide film, a pH sensor such as an ISFET (ion-sensitive electrolytic effect transistor), other ion-selective electrodes, or the like can be used.

The detection electrode 31 is arranged so as to be in contact with the reaction liquid flowing in the introduction part 11, and the detection electrode 41 is arranged in contact with the reaction liquid flowing in the outflow part 13.
FIG. 3 is a cross-sectional view of the vicinity of the detection electrode 41 along the line III-III in FIG. As shown in FIG. 3, the detection electrode 41 is arranged so as to cover the upper surface of the outflow portion 13, and can thereby come into contact with the reaction liquid flowing through the outflow portion 13. Similarly, the detection electrode 31 is also arranged so as to cover the upper surface of the introduction part 11, so that it can come into contact with the reaction liquid flowing through the introduction part 11.

The depth d3 of the portion where the detection electrodes 31 and 41 of the reaction liquid channel 10 are provided is preferably 1 to 500 μm. The upper limit value of the depth d3 is more preferably 200 μm or less, further preferably 50 μm or less, and particularly preferably 30 μm or less. If the depth d3 is too large, the potential generated from the detection electrode tends to become unstable. The width w3 of the portion where the detection electrodes 31 and 41 are provided is preferably (d3 × 2 + 10) to (d3 × 2 + 20) μm.
The depth and width of the reaction liquid channel 10 other than the portion where the detection electrodes 31 and 41 are provided do not directly affect the stability of the potential generated from the detection electrode. The width is preferably substantially uniform. Thereby, the flow of the reaction liquid becomes uniform, and the problem of liquid accumulation in the middle of the flow path can be avoided.

The reaction liquid channel length between the detection electrode 31 and the detection electrode 41 is preferably 0.1 to 100 cm. The reaction liquid channel length is a distance along the flow direction of the channel, and when the channel is a curve, it is a distance along the curve.
When the reaction liquid channel length is less than 1 cm, the length of the collecting part 12 (reaction part) cannot be taken sufficiently, and the reaction between the reaction liquid and the sample gas may be insufficient. When the reaction liquid channel length exceeds 10 cm, the electrical continuity between the detection electrode 31 and the detection electrode 41 becomes insufficient, and it may be difficult to detect the potential difference stably.
The reaction liquid channel length between the detection electrodes is more preferably 1 to 10 cm.

The flow rate of the reaction solution is preferably 0.01 to 1000 μL / min, more preferably 0.1 to 100 μL / min, and further preferably 0.1 to 10 μL / min. When the flow rate of the reaction solution is too small, there are problems such as a long reaction time. If the flow rate of the reaction solution is too large, there are problems such as an increase in the consumption of the reaction solution and difficulty in analyzing low concentration gas.
In this embodiment, there is a restriction on the flow rate of the reaction solution for achieving the laminar flow state in the collecting portion 12, and if the laminar flow state is achieved, the flow rate of the reaction solution is usually 0.01 to 1000 μL. / Min.

Ionic strength of the reaction solution is preferably from ¹⁰ -7 to 10 ^0, more preferably 10 -5 ^{to 10 -1,} more preferably 10 -3 ^{to 10 -1.} If the ionic strength of the reaction solution is too small, the S / N ratio increases and there is a problem that the influence of noise becomes significant. If the ionic strength of the reaction solution is too high, there is a problem that the activity and the concentration are greatly deviated and an appropriate analysis result cannot be obtained.

  The gas analysis unit according to the present embodiment connects the terminal 32 of the detector 30 and the terminal 42 of the detector 40 to an analyzer main body (not shown), and generates a potential difference between the detection electrode 31 and the detection electrode 41. taking measurement. Thereby, the change in the properties of the reaction liquid before and after the gathering portion 12 due to the reaction with the sample gas can be measured, and as a result, the concentration of the component reacting with the reaction liquid in the sample gas can be obtained.

  In the present embodiment, the reaction liquid and the sample gas flow in the same direction and react in a laminar flow state at the collecting portions 12 and 22, but the sample gas inlet 20a and the sample gas outlet 20b are reversed. Thus, the reaction gas reaction liquid and the sample gas may flow in opposite directions, and may react in the countercurrent state at the collecting portions 12 and 22. Further, as disclosed in JP-A-2005-329364, the reaction gas and the sample gas may cross each other so that they react at the crossing portion.

[Second Embodiment]
4 is a perspective view showing a gas analyzing unit and a gas analyzer according to a second embodiment of the present invention, FIG. 5 is a VV sectional view of FIG. 4, FIG. 6 is a VI-VI partial sectional view of FIG. These are the VII-VII partial sectional views of FIG. As shown in FIG. 4, the gas analysis unit of the present embodiment includes a reaction liquid channel 51 provided in the substrate 50, a gas-liquid separator 60 that separates the reaction liquid channel 51 and the outside of the substrate 50, and a reaction. Detectors 70 and 80 provided in contact with the liquid flow path 51 are provided. In addition, an analyzer main body 90 is connected to the gas analysis unit to constitute the gas analyzer of the present embodiment.

As a material of the substrate 50, a material equivalent to the substrate 1 of the first embodiment can be used. Moreover, although the board | substrate 50 is made into flat form, there is no limitation in particular in a shape.
As shown in FIGS. 5 and 6, the gas-liquid separator 60 is provided in contact with the substantially central portion of the reaction liquid channel 51 and exists outside the substrate 50 via the gas-liquid separator 60. The sample gas can be absorbed into the reaction solution.
That is, in this embodiment, the part of the reaction liquid channel 51 that is in contact with the gas-liquid separator 60 is a reaction part where the reaction liquid reacts with the sample gas.
The depth d4 of the part in contact with the gas-liquid separator 60 of the reaction liquid channel 51 is preferably 1 to 500 μm. The upper limit value of the depth d4 is more preferably 100 μm or less, further preferably 50 μm or less, and particularly preferably 30 μm or less. If the depth d4 is too large, it is difficult to uniformly absorb the sample gas into the reaction solution. In addition, the width w4 of the portion of the reaction liquid channel 51 that is in contact with the gas-liquid separator 60 is preferably (d4 × 2 + 10) to (d4 × 2 + 20) μm.

  As shown in FIGS. 4 and 5, a reaction solution introduction port 51 a that communicates with the outside of the substrate 50 and into which the reaction solution is introduced is provided at the upstream end of the reaction solution channel 51. A reaction liquid outlet 51 b that communicates with the outside of the substrate 50 and flows out of the reaction liquid is provided at the downstream end of the reaction liquid flow path 51.

The detector 70 includes a detection electrode 71 that generates a potential according to the properties of the reaction solution, and a terminal 72 connected to the detection electrode 71. The detector 80 includes a detection electrode 81 that generates a potential according to the properties of the reaction solution, and a terminal 82 connected to the detection electrode 81.
As the detection electrode 71 and the detection electrode 81, the thing similar to the detection electrode 31 and the detection electrode 41 of 1st Embodiment can be used.

  As the gas-liquid separator 60, a porous structure such as a fluorine-based porous polymer sheet, porous silicon, a polydimethylsiloxane polymer thin plate, porous glass, etc., a non-porous substrate is provided with fine slits, fine pores, etc. The gas-liquid-separable structure obtained can be used.

The detection electrode 81 is a reaction that flows through the reaction liquid channel 51 on the downstream side of the gas-liquid separator 60 so that the detection electrode 71 is in contact with the reaction liquid that flows through the reaction liquid channel 51 on the upstream side of the gas-liquid separator 60. Each is arranged so as to come into contact with the liquid.
As shown in FIG. 7, the detection electrode 81 is disposed so as to cover the upper surface of the reaction liquid flow path 51, and can thereby come into contact with the reaction liquid flowing through the reaction liquid flow path 51. Similarly, the detection electrode 71 is also arranged so as to cover the upper surface of the reaction liquid channel 51, so that it can come into contact with the reaction liquid flowing in the reaction liquid channel 51.

The depth d5 of the portion where the detection electrodes 71 and 81 of the reaction liquid channel 51 are provided is preferably 1 to 500 μm. The upper limit of the depth d5 is more preferably 200 μm or less, further preferably 50 μm or less, and particularly preferably 30 μm or less. If the depth d5 is too large, the potential generated from the detection electrode tends to become unstable. Moreover, it is preferable that the width w5 of the part in which the detection electrodes 71 and 81 of the reaction liquid channel 51 are provided is (d5 × 2 + 10) to (d5 × 2 + 20) μm.
The depth and width of the reaction liquid channel 51 other than the portion where the detection electrodes 71 and 81 are provided do not directly affect the stability of the potential generated from the detection electrode. The width and width are preferably substantially uniform. Thereby, the flow of the reaction liquid becomes uniform, and the problem of liquid accumulation in the middle of the flow path can be avoided.

The reaction liquid channel length between the detection electrode 71 and the detection electrode 81 is preferably 0.1 to 100 cm. When the reaction liquid channel length is less than 1 cm, the reaction liquid channel 51 (reaction part) in contact with the gas-liquid separator 60 cannot be sufficiently long, and the reaction between the reaction liquid and the sample gas becomes insufficient. There is. When the reaction liquid channel length exceeds 10 cm, the electrical continuity between the detection electrode 71 and the detection electrode 81 becomes insufficient, and it may be difficult to stably detect the potential difference.
The reaction liquid channel length between the detection electrodes is more preferably 1 to 10 cm.

Similar to the first embodiment, the flow rate of the reaction solution is preferably 0.01 to 1000 μL / min, more preferably 0.1 to 100 μL / min, and 0.1 to 10 μL / min. More preferably.
Also, the ionic strength of the reaction solution is preferably from ¹⁰ -7 to 10 ^0, more preferably 10 -5 ^{to 10 -1,} more preferably 10 -3 ^{to 10 -1.}

  The gas analysis unit according to the present embodiment connects the terminal 72 of the detector 70 and the terminal 82 of the detector 80 to the analyzer body 90 and measures the potential difference between the detection electrode 71 and the detection electrode 81. As a result, the change in the properties of the reaction liquid due to the reaction with the sample gas outside the substrate 50 can be measured, and as a result, the concentration of the component reacting with the reaction liquid in the sample gas can be obtained.

[Example 1]
The ammonia gas was measured under the following conditions using the gas analysis unit of the embodiment of FIG.
(Specifications of gas analysis unit)
Introduction part 11 and outflow part 13 of reaction liquid channel 10: width 80 μm, depth 30 μm,
Collecting portion 12 of reaction liquid flow path 10: width 70 μm, depth 30 μm,
Introduction part 21 and outflow part 23 of sample gas channel 20: width 180 μm, depth 80 μm,
Collecting portion 22 of sample gas flow path 20: width 178 μm, depth 80 μm,
The length of the gathering parts 12 and 22: 10 mm,
Reaction liquid channel length between the detection electrode 31 and the detection electrode 41: 15 mm,
Width of detection electrode 31 and detection electrode 41 (flow direction): 0.5 mm,
The thickness of the detection electrode 31 and the detection electrode 41: 250 nm,
Material (surface) of detection electrode 31 and detection electrode 41: iridium oxide

(Measurement conditions, etc.)
Reaction solution: ammonium chloride solution (concentration: 6 × 10 ⁻³ mol / L)
Reaction liquid flow rate: 1 μL / min Sample gas: 0 to 194 ppm of ammonia gas (nitrogen gas base)
Sample gas flow rate: 2 μL / min Measurement temperature: Room temperature (22 ° C.)

  Table 1 and FIG. 8 show the potential difference between the detection electrode 31 and the detection electrode 41 according to the ammonia gas concentration. The horizontal axis in FIG. 8 is a logarithmic scale. Table 2 and FIG. 9 show changes in potential difference between the detection electrode 31 and the detection electrode 41 after the ammonia gas concentration is switched from 0 ppm to 194 ppm.

  As shown in Table 1 and FIG. 8, a potential difference corresponding to the ammonia gas concentration was obtained. Further, as shown in Table 2 and FIG. 9, a potential difference following the sample gas concentration was obtained in about 2 to 3 minutes. In addition, it is considered that the time until the potential difference following the sample gas concentration is obtained mainly depends on the time related to the movement of the reaction solution, that is, the reaction solution flow rate.

[Example 2]
Carbon dioxide gas was measured under the following conditions using the gas analysis unit of the embodiment of FIG.
(Specifications of gas analysis unit)
Same as Example 1

(Measurement conditions, etc.)
Reaction solution: bicarbonate ion solution (concentration: 0.02 mol / L)
Reaction liquid flow rate: 1 μL / min Sample gas: 0-9997 ppm of carbon dioxide gas (based on nitrogen gas)
Sample gas flow rate: 2 μL / min Measurement temperature: Room temperature (22 ° C.)

  Table 3 and FIG. 10 show the potential difference between the detection electrode 31 and the detection electrode 41 according to the carbon dioxide gas concentration. The horizontal axis in FIG. 10 is a logarithmic scale. Table 4 and FIG. 11 show changes in the potential difference between the detection electrode 31 and the detection electrode 41 after the carbon dioxide gas concentration is switched from 0 mg / L to 9997 mg / L.

  As shown in Table 3 and FIG. 10, a potential difference corresponding to the carbon dioxide gas concentration was obtained. Further, as shown in Table 4 and FIG. 11, a potential difference following the sample gas concentration was obtained in about 120 minutes. In addition, it is considered that the time until the potential difference following the sample gas concentration is obtained mainly depends on the time required for the movement of the reaction solution, that is, the reaction solution flow rate.

It is a top view which shows 1st Embodiment, FIG. 1 (a) is a general view, FIG.1 (b)-(d) is a principal part enlarged view. It is II-II sectional drawing of FIG.1 (c). It is a III-III partial sectional view of Drawing 1 (a). It is a perspective view which shows 2nd Embodiment. It is VV sectional drawing of FIG. It is VI-VI sectional drawing of FIG. It is VII-VII sectional drawing of FIG. It is a graph which shows the electric potential difference according to ammonia gas concentration. It is a graph which shows the electrical potential difference change after switching ammonia gas concentration. It is a graph which shows the electric potential difference according to a carbon dioxide gas concentration. It is a graph which shows the electrical potential difference change after switching a carbon dioxide gas density | concentration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,50 ... Board | substrate, 10,51 ... Reaction liquid flow path, 20 ... Sample gas flow path,
30, 40, 70, 80 ... detector, 60 ... gas-liquid separator, 90 ... analyzer body

Claims (7)

A reaction liquid flow path through which the reaction liquid flows;
The reaction liquid channel includes a first detection electrode and a second detection electrode sequentially provided from the upstream side so as to come into contact with the reaction liquid in the reaction liquid channel, and the reaction liquid channel includes the first detection electrode and the second detection electrode. In between, the reaction solution has a reaction part that reacts with the sample gas,
The first detection electrode generates a potential according to the properties of the reaction solution on the upstream side of the reaction unit,
The gas detection unit, wherein the second detection electrode generates a potential corresponding to the property of the reaction solution on the downstream side of the reaction section. Furthermore, a sample gas flow path through which the sample gas flows is provided,
The gas analysis unit according to claim 1, wherein the reaction part of the reaction liquid channel is adjacent to the sample gas channel in a state in which an internal fluid can contact each other. Furthermore, a gas-liquid separator is provided,
The gas analysis unit according to claim 1, wherein a reaction part of the reaction liquid channel is in contact with a sample gas through the gas-liquid separator.   The gas analysis unit according to any one of claims 1 to 3, wherein a maximum depth of a portion of the reaction liquid channel where the first detection electrode and the second detection electrode are provided is 1 to 500 µm.   A gas analyzer comprising: the gas analysis unit according to any one of claims 1 to 4; and an analyzer main body that detects a potential difference between the first detection electrode and the second detection electrode.   A gas analysis method for analyzing the sample gas by measuring a potential difference between the first detection electrode and the second detection electrode of the gas analysis unit according to any one of claims 1 to 4, wherein the reaction A gas analysis method, wherein a flow rate of a reaction solution in a liquid channel is 0.01 to 1000 μL / min. Gas analyzing method according to claim 6 ionic strength of the reaction solution is ¹⁰ -7 to 10 ^0.

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