Ion analysis device and ion analysis method

Abstract

Provided is an ion analysis device capable of performing measurements using a sample liquid with a smaller liquid volume than conventional methods. The ion analysis device comprises: a measurement electrode provided with a response unit which responds to ions; a reference electrode provided with a liquid junction section; a measurement flow path in which the response membrane and the liquid junction section are disposed; and a calculation unit that calculates the ion concentration in the sample liquid on the basis of the potential difference between the measurement electrode and the reference electrode, the device further comprising a hydrophilic section connecting the response unit and the liquid junction section inside the measurement flow path.

Description

Ion analysis device and ion analysis method

[0001] The present invention relates to an ion separation device and an ion analysis method for measuring the concentration of ions contained in a sample liquid.

[0002] In an ion analyzer that is equipped with a measurement electrode and a comparison electrode and measures an ion concentration based on the potential difference generated between the measurement electrode and the comparison electrode, the measurement must be performed while both the measurement electrode and the comparison electrode are in contact with the sample liquid to be measured. Therefore, when the amount of sample liquid obtained at one time is very small, measures have been taken such as waiting until a certain amount of sample liquid has accumulated before measuring the ion concentration, or diluting the sample liquid to increase the amount of sample solution before measuring.

[0003] However, if one waits until a certain amount of sample liquid has accumulated, for example, when the purpose is to detect a change in the state of a hydrogen reactor such as a fuel cell from a change in the concentration of ionic components contained in the gas discharged from the hydrogen reactor, there is a risk that the change in state of the hydrogen reactor will not be immediately reflected in the measurement results of the ion concentration. Even if a pH measurement device for trace measurements such as that described in Patent Document 1 is used, the flow path must be filled with sample liquid so that both the response membrane of the measurement electrode and the liquid junction of the reference electrode come into contact with the sample liquid, and therefore a supply of sample liquid at least 500 μm / min is required.

[0004] Furthermore, when a method of diluting the sample liquid is adopted, the smaller the amount of sample liquid, the more accurately a dilution mechanism is required to dilute the sample liquid.

[0005] Patent No. 6804956

[0006] The present invention has been made in view of the above-mentioned problems, and has as its object to provide an ion analyzer that is capable of performing measurements using a smaller amount of sample liquid than conventional ones.

[0007] That is, the ion analysis device according to the present invention is an ion analysis device comprising a measurement electrode having a response part that responds to ions, a comparison electrode having a liquid junction, a measurement flow path in which the response part and the liquid junction are arranged, and a calculation part that calculates the ion concentration based on the potential difference between the measurement electrode and the comparison electrode, and is characterized by further comprising a hydrophilic part inside the measurement flow path that connects the response part and the liquid junction.

[0008] Such an ion analyzer further includes a hydrophilic section inside the measurement flow path that connects the response section and the liquid junction. Therefore, even if, for example, the amount of sample liquid flowing through the measurement flow path is small and the measurement flow path is not filled, a hydrophilic section is provided to connect the response section and the liquid junction. As a result, the sample liquid spreads over the surface of this hydrophilic section so as to come into contact with the response section and the liquid junction, electrically connecting the response section and the liquid junction via the sample liquid, and measurement can be performed.

[0009] It is preferable that the response part and the liquid junction part are arranged so as to face each other across the measurement flow path, since this allows the distance between the response part and the liquid junction part to be as close as possible.

[0010] A specific embodiment of the present invention is one in which the response unit and the liquid junction unit are arranged facing each other across the measurement flow path, and the liquid junction unit is arranged downstream of the response unit.

[0011] The contact angle of the surface of the hydrophilic portion is preferably 90° or less.

[0012] Specific examples of the hydrophilic portion include a hydrophilic surface layer provided on the inner wall of the measurement flow channel, or a hydrophilic member disposed inside the measurement flow channel.

[0013] It is preferable to further include a cooling section that is provided upstream of the response section in the measurement flow path and that cools the measurement flow path, because this can liquefy the water vapor flowing within the measurement flow path, thereby increasing the amount of sample liquid as much as possible and further improving measurement accuracy.

[0014] It is preferable to further provide a fixing mechanism that fixes the measurement electrode and / or the comparison electrode to the measurement flow path with a screw, because this allows the measurement electrode and the comparison electrode to be stably fixed to the measurement flow path even when pressure is applied within the measurement flow path.

[0015] As described above, according to the present invention, it is possible to measure the ion concentration of a sample liquid even when an even smaller amount of sample liquid is supplied than in the past. As a result, it is possible to analyze changes in ion concentration in the sample liquid more responsively and in real time than when measuring sample liquid by storing it in a reservoir. Furthermore, because there is no need to dilute the sample liquid, it is possible to accurately measure the ion concentration in the sample liquid with as simple a configuration as possible.

[0016] FIG. 1 is a schematic view of an entire ion analysis device according to one embodiment of the present invention; FIG. 2 is a schematic view of an enlarged portion of the ion analysis device according to the present embodiment; FIG. 3 is a schematic view of an enlarged portion of the ion analysis device according to the present embodiment; FIG. 4 is a view showing an example of an ion analysis result using the ion analysis device according to the present embodiment; FIG. 5 is a view showing an example of an ion analysis result using the ion analysis device according to the present embodiment; FIG. 6 is a schematic view of a fuel cell evaluation system using the ion analysis device according to the present embodiment; FIG. 7 is a schematic view of a fuel cell evaluation system according to another embodiment; FIG. 8 is a schematic view of a fuel cell evaluation system according to another embodiment;

[0017] An ion analyzer according to the present invention will be described below with reference to the drawings. The ion analyzer 1 according to this embodiment is capable of measuring the ion concentration in a sample solution S to be measured. The ion analyzer 1 in this embodiment calculates pH and the like based on the so-called glass electrode method, and as shown in FIG. 1 , includes a measurement electrode 11 having a response glass 111, a reference electrode 12 having a liquid junction 121, a measurement flow path 13 in which the response glass 111 and the liquid junction 121 are disposed, and a calculation unit 14 that calculates the ion concentration in the sample solution based on the potential difference between the measurement electrode 11 and the reference electrode 12.

[0018] As shown in Figure 2, the measuring electrode 11 comprises a cylindrical first housing 113 containing a first internal liquid 112 therein, a response glass 111 provided at the tip of the first housing 113, and a first internal electrode 114 immersed in the first internal liquid 112.

[0019] The sensitive glass 111 is interposed between the first internal liquid 112 and the sample solution S to be measured, and generates a potential due to the difference in ion concentration therebetween, and a known sensitive glass can be used. In this embodiment, the sensitive glass 111 is attached to the tip of the first housing 113 and forms the tip of the first housing 113.

[0020] The first internal liquid 112 is, for example, a phosphate buffer solution.

[0021] The first housing 113 is, for example, cylindrical and made of a material such as glass, PVC (polyvinyl chloride), PP (polypropylene), PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), or PFA (perfluoroalkoxy fluororesin).

[0022] The first internal electrode 114 is, for example, rod-shaped or long plate-shaped and made of silver / silver chloride, and is attached so as to penetrate the wall surface of the end opposite to the end made of responsive glass of the first housing 113, with one end immersed in the first internal liquid 112, and the other end connected to a cable for extracting a signal from this first internal electrode 114.

[0023] As shown in Figure 2, the comparison electrode 12 includes a cylindrical second housing 123 that stores a second internal liquid 122 therein, a second internal electrode 124 that is immersed in the second internal liquid 122 and outputs a reference potential, and a liquid junction 121.

[0024] The liquid junction 121 may be any member that can ensure conductivity between the second internal liquid 122 and the second internal electrode 124, but in this embodiment, a rod-shaped liquid junction 121 made of porous glass is used as an example. One end of the liquid junction 121 is disposed inside the second housing 123 and immersed in the second internal liquid 122, and the other end is fixed to the second housing 123 so as to protrude from the second housing 123 toward the measurement flow path 13 side.

[0025] The second internal liquid 122 is, for example, a 3.3 M KCl aqueous solution.

[0026] The second housing 123 is cylindrical and made of a material such as PVC (polyvinyl chloride), PP (polypropylene), PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy fluororesin), or Poly Ether Ether Ketone.

[0027] The second internal electrode 124 is, for example, rod-shaped or long plate-shaped and made of silver / silver chloride, and is attached so as to penetrate the wall surface at the end opposite to the side where the liquid junction 121 is provided of the second housing 123, with one end immersed in the second internal liquid 122, and a cable for extracting a reference potential from this second internal electrode 124 attached to the other end.

[0028] The measurement flow path 13 is, for example, a capillary-like tube with a substantially circular cross-sectional shape and an inner diameter of 0.05 mm to 10 mm, preferably 0.1 mm to 5 mm, and more preferably 0.5 mm to 3 mm. In this embodiment, the measurement flow path 13 is formed inside and penetrates a measurement flow path forming member 131 made of a resin such as Poly Ether Ether Ketone (polyether ether ketone), PVC (polyvinyl chloride), PP (polypropylene), PVDF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxy fluororesin), PMMA (methyl methacrylate), PC (polycarbonate), PET (polyethylene terephthalate), or ceramic, which has excellent pressure resistance, chemical resistance, and heat resistance.

[0029] In this embodiment, the ion analysis device 1 further includes a fixing mechanism 15 that fixes the aforementioned measurement electrode 11 and reference electrode 12 to the measurement flow path forming member 131, and this fixing mechanism 15 fixes the response glass 111 and the liquid junction 121 so that their tips slightly protrude into the measurement flow path 13 so as to come into contact with the sample liquid S in the measurement flow path 13, or so that they are positioned flush with the inner wall of the measurement flow path 13.

[0030] As shown in Figure 3, the fixing mechanism 15 includes, for example, a first fixing member 151 that holds the measurement electrode 11 and fixes it to the measurement flow path forming member 131, a second fixing member 152 that holds the comparison electrode 12 and fixes it to the measurement flow path forming member 131, a first mating hole 153 formed in the measurement flow path forming member 131 for fixing the first fixing member 151 therein, and a second mating hole 154 formed in the measurement flow path forming member 131 for fixing the second fixing member 152 therein.

[0031] The first fixing member 151 is, for example, a tubular member having an inner surface that fits into the side surface of the first housing 113, and a side surface on the side surface for fitting into the first fitting hole 153, and has a screw thread formed on its outer surface.

[0032] The second fixing member 152 is, for example, a tubular member having an inner peripheral surface that fits into the side peripheral surface of the rod-shaped member that constitutes the liquid junction 121, and a side peripheral surface for fitting into the second fitting hole 154 on the side peripheral surface, and a screw thread is formed on the outer peripheral surface.

[0033] The first mating hole 153 has, for example, a screw thread formed on its inner surface that mates with the screw thread formed on the outer surface of the first fixing member 151, and the first fixing member 151 is fixed by screwing it into this screw thread.

[0034] The second engagement hole 154 has, for example, a second fixing member accommodating portion 154a that accommodates the second fixing member 152 therein and a second housing accommodating portion 154b that accommodates the second housing 123 therein, and the inner circumferential surface of the second fixing member accommodating portion 154a is formed with threads that mate with the threads formed on the outer circumferential surface of the second fixing member 152. Furthermore, the inner circumferential surface of the second housing accommodating portion 154b is formed along the outer diameter of the second housing 123 so as to hold the outer circumferential surface of the second housing 123 without rattle, and the reference electrode 12 can be fixed to the measurement flow path 13 by screwing the second fixing member 152 into the threads formed on the second fixing member accommodating portion 154a.

[0035] 2 and 3, in this embodiment, the response glass 111 and the liquid junction 121 are fixed to the measurement flow path 13 so that they face each other with the measurement flow path 13 in between. The response glass 111 and the liquid junction 121 may be arranged so that they face each other with the measurement flow path 13 in between, but in order to further improve measurement accuracy, it is preferable that the response glass 111 be arranged upstream of the liquid junction 121.

[0036] The calculation unit 14 is an information processing circuit that includes a digital circuit configured with a CPU, memory, communication port, etc., an analog circuit equipped with a buffer, amplifier, etc., and an AD converter, DA converter, etc. that mediate between the digital circuit and the analog circuit. The information processing circuit is configured to function as a calculation unit by the CPU and its peripheral devices working together in accordance with a predetermined program stored in the memory.

[0037] The ion analyzer 1 according to this embodiment further includes a hydrophilic portion 16 provided in the measurement flow path 13 to connect the response glass 111 and the liquid junction 121 .

[0038] In this embodiment, the hydrophilic portion 16 is a hydrophilic member 161 disposed in the measurement flow path 13, and as shown in Figures 2 and 3, is disposed so as to be in contact with both the response glass 111 and the liquid junction 121 within the measurement flow path 13. The hydrophilic member 161 is not particularly limited as long as it has a hydrophilic surface, but in this embodiment, one example is a lump of glass wool. The water contact angle of the surface of the hydrophilic member 161 is preferably 90° or less, and more preferably 80° or less.

[0039] The ion analyzer 1 configured as described above includes the hydrophilic member 161 disposed in the measurement flow path 13 to connect the sensitive glass 111 and the liquid junction 121. Therefore, even if the amount of sample liquid S flowing in the measurement flow path 13 is so small that the space between the sensitive glass 111 and the liquid junction 121 in the measurement flow path 13 cannot be liquid-tightly filled with the sample liquid S, the sample liquid S that spreads along the surface of the hydrophilic member 161 can be made to contact both the sensitive glass 111 and the liquid junction 121. As a result, even if the inner diameter of the measurement flow path 13 is 1 mm and the flow rate of the sample liquid S through the measurement flow path 13 is 0.001 ml / min or more and 0.5 ml / min or less, and a gas-liquid mixed sample is flowing in such a way that only intermittent droplets are barely supplied to the measurement flow path 13, the ion concentration of the sample liquid S can be accurately measured. FIG. 4 shows measurement data obtained by actually measuring a gas-liquid mixture sample and a liquid-only sample using the ion analyzer 1 according to this embodiment, with a measurement flow path 13 having an inner diameter of 1 mm. As can be seen from FIG. 4, the ion analyzer 1 according to this embodiment can stably measure a gas-liquid mixture sample with the same accuracy as a sample with a large amount of liquid and only liquid flowing. FIG. 5 also compares the measurement results of a gas-liquid mixture sample obtained by the ion analyzer 1 according to this embodiment, which includes a hydrophilic member 161 in the measurement flow path 13, with those obtained by a conventional ion analyzer without a hydrophilic member 161. It can also be seen from FIG. 5 that the ion analyzer 1 according to this embodiment, which includes a hydrophilic portion, can stably measure ion concentrations without fluctuations in the readings.

[0040] Furthermore, according to the ion analysis device 1 of this embodiment, the response glass 111 and the liquid junction 121 are arranged to face each other across the measurement flow path 13. This allows the distance between the response glass 111 and the liquid junction 121 to be shorter than when the response glass 111 and the liquid junction 121 are arranged side by side and the measurement electrode 11 and the reference electrode 12 are arranged side by side, so that the device can also be used when the amount of sample liquid is smaller.

[0041] By making the water contact angle of the surface of the hydrophilic member 161 90° or less, the sample liquid S can be spread as thinly and widely as possible on the surface of the hydrophilic member 161, making it easier for the sample liquid S to come into contact with both the response glass 111 and the liquid junction 121, and it is also possible to accommodate cases where only a small amount of sample liquid S is obtained.

[0042] The fixing mechanism 15 fixes the measurement electrode 11 and the comparison electrode 12 to the measurement flow path 13 with screws, so that even when the pressure in the measurement flow path 13 is high, the response glass 111 of the measurement electrode 11 and the liquid junction 121 of the comparison electrode 12 can be stably fixed to the measurement flow path 13.

[0043] The ion analyzer 1 according to this embodiment, which can achieve such effects, can be used for any purpose as long as it is used to measure ion concentrations, but is particularly suitable for use in an evaluation system 100 that evaluates changes in the state of a hydrogen reactor, such as a fuel cell FC, based on changes in the ion concentration contained in gas discharged from the hydrogen reactor.

[0044] In a fuel cell FC, which obtains energy by reacting hydrogen and oxygen, the reaction between hydrogen and oxygen produces water. However, it is known that the concentration of ions eluted in this produced water changes when components inside the fuel cell FC deteriorate. However, the amount of produced water discharged from the fuel cell FC varies greatly depending on the operating state and size of the fuel cell FC, and in some cases, only a very small amount of produced water is discharged. Even in such cases, the state of the fuel cell FC changes every moment. Therefore, when attempting to monitor changes in the state of the fuel cell in real time, it is extremely advantageous to use an analyzer that can measure ion concentrations using as small a volume of liquid as possible, such as the ion analyzer 1 according to this embodiment. Furthermore, the ion analyzer 1 according to this embodiment can be used not only to evaluate the fuel cell FC as a whole, but also to evaluate each cell that constitutes the fuel cell FC individually or in groups of cells containing a small number of cells, such as two or three.

[0045] As shown in FIG. 6, the evaluation system 100 includes an exhaust gas flow path L1 through which gas discharged from the anode side and / or cathode side of the fuel cell FC flows, an ion analyzer 1 that analyzes ions contained in the gas flowing through the exhaust gas flow path L1, and a judgment unit 2 that evaluates the state of the fuel cell based on the analysis results by the ion analyzer 1.

[0046] The exhaust gas flow path L1 is connected to the fuel cell FC and allows the gas discharged from the fuel cell FC to circulate therethrough, and is formed from a tube or the like made of a material that can withstand the heat, pressure, and chemicals of the gas discharged from the fuel cell FC.

[0047] In the evaluation system 100 described in this embodiment, an ion analyzer 1 is disposed on an exhaust gas flow path L1. Specifically, the exhaust gas flow path L1 is connected to the measurement flow path via a connection port provided in a measurement flow path forming member of the ion analyzer 1 described above, and the ion analyzer 1 is configured to be able to measure the concentration of ions contained in the produced water contained in the gas immediately after it is discharged from the fuel cell FC.

[0048] The judgment unit 2 judges the deterioration state of the fuel cell FC by, for example, comparing various ion concentrations, such as the pH value output from the ion analysis device 1, with predetermined threshold values ​​for various ions that are set in advance to judge the state of the fuel cell FC.

[0049] The determination unit 2 is an information processing circuit including a digital circuit configured with a CPU, memory, communication port, etc., an analog circuit equipped with a buffer and amplifier, etc., and an AD converter, DA converter, etc. that mediate between the digital circuit and the analog circuit. The information processing circuit is configured to function as the determination unit 2 by the CPU and its peripheral devices working together in accordance with a predetermined program stored in the memory. The information processing circuit that performs the function of the determination unit 2 may be shared with the information processing circuit that performs the function of the calculation unit described above, or may be a separate information processing circuit. In addition to the above, the evaluation system 100 may also include a condensation unit (not shown) that cools and condenses the sample liquid S that has passed through the ion analyzer 1.

[0050] The present invention is not limited to the above-described embodiment. For example, the hydrophilic portion 16 is not limited to a hydrophilic member, and may be a hydrophilic surface layer formed on the inner surface of the measurement flow path. This hydrophilic surface layer is formed, for example, over an area of ​​the inner surface of the measurement flow path that includes the portion between the response glass and the liquid junction. It can be formed by, for example, surface treating the inner surface of the measurement flow path with an existing surface treatment agent. The water contact angle of the surface of the hydrophilic surface layer that comes into contact with the sample liquid is preferably 90° or less, and more preferably 80° or less. The measurement flow path itself, formed of a hydrophilic material, may also function as the hydrophilic portion 16. Alternatively, the sample liquid itself may function as the hydrophilic portion 16. Specifically, a surfactant or the like may be added to the sample liquid so that the sample liquid spreads along the inner surface of the measurement flow path and contacts the response glass and the liquid junction.

[0051] The positional relationship between the measurement electrode 11 and the reference electrode 12 is not limited to that described above. It is preferable that the distance between the response glass 111 and the liquid junction 121 is short, but the response glass 111 and the liquid junction 121 may be arranged side by side on the same side of the measurement device, or may be arranged opposite each other across the measurement flow path 13, with the response glass 111 and the liquid junction 121 offset by a predetermined angle (for example, any angle greater than 0° and up to 180°, such as 90° or 120°) in the circumferential direction of the measurement flow path 13.

[0052] The measuring electrode 11 and the reference electrode 12 may be, for example, electrodes for measuring pH, but are not limited to this. The ions to be measured can be changed as appropriate depending on the type of fuel cell FC, and may be, for example, one or more ions selected from the group consisting of pH, fluorine ions, sodium ions, potassium ions, etc. Note that, while the above-described embodiment has been described as using a measuring electrode equipped with a sensitive glass, the present invention is not limited to this, and a measuring electrode equipped with a sensitive part that responds to ions, such as a sensitive membrane that responds to ions, may also be used.

[0053] In the evaluation system 100 of FIG. 6, an ion analyzer is provided on both the anode side and / or the cathode side of the fuel cell FC, but an ion analyzer may be provided on only one side.

[0054] As shown in FIG. 7 , if the ion analyzer 1 or the evaluation system 100 further includes a cooling unit 17 that cools the gas flowing in the exhaust gas flow path L1 upstream of the response glass 111, the amount of the sample liquid can be increased by liquefying the water vapor contained in the exhaust gas as needed.

[0055] The ion analyzer 1 may be provided on the exhaust gas flow path L1, or may be provided outside the exhaust gas flow path L1 as shown in FIG. 8 . When the ion analyzer 1 is provided outside the exhaust gas flow path L1, either the ion analyzer 1 or the evaluation system 100 may further include a sampling unit 18 that samples a portion or all of the produced water or condensed liquid from the exhaust gas flow path L1 and supplies the sample liquid to the measurement flow path 13 of the ion analyzer 1. The sampling unit 18 samples, for example, the produced water or condensed liquid stored in a first storage unit 181 formed on the exhaust gas flow path L1 on the anode side and / or cathode side of the fuel cell FC as a sample liquid and supplies the sample liquid to the measurement flow path 13 of the ion analyzer 1. The sampling unit 18 may include an introduction path 182 that connects the first storage unit 181 and the measurement flow path 13. The inlet path 182 is provided, for example, to branch off from the exhaust gas flow path L1, and is formed, for example, by a capillary-shaped pipe that connects a sampling port formed downward from the lowest position on the tapered bottom surface of the first storage section 181 to the measurement flow path 13 of the ion analysis device 1.

[0056] 9 , the sampling unit 18 may be configured to sample a part or all of the exhaust gas from the exhaust gas flow path L1, store the produced water or condensed liquid in the sampled exhaust gas as a sample liquid in a second storage unit 183, and introduce the produced water or condensed liquid stored in the second storage unit 183 into the measurement flow path 13 of the ion analyzer 1 provided outside the exhaust gas flow path L1. In this case, the sampling unit 18 is provided so as to branch off from the exhaust gas flow path L1 through which the exhaust gas from the fuel cell FC flows, and includes a sampling flow path 184 connecting the exhaust gas flow path L1 and the second storage unit 183. The second storage unit 183 may be a gas-liquid separator that separates and removes bubbles from the sample liquid supplied to the measurement flow path 13 of the ion analyzer 1. When the sample liquid is introduced from the second reservoir 183 into the measurement flow path 13, the introduction path 182 is formed by a capillary pipe connecting a sampling port formed on the bottom surface of the second reservoir 183 to the measurement flow path 13 of the ion analyzer 1. Furthermore, when the second reservoir 183 is a gas-liquid separation section, the introduction path 182 may be provided with an exhaust port provided in the gas-liquid separation section and a return flow path (not shown) connecting the exhaust gas flow path L1 to a downstream side of the connection portion of the exhaust gas flow path L1 with the sampling flow path 184, and a return pump (not shown) that sends gas into the exhaust gas flow path L1 via the return flow path. This return pump may be controlled, for example, by a return gas control section whose role is played by the information processing circuit described above.

[0057] The sampling unit 18 may further include a liquid volume detection means for detecting the volume of sample liquid stored in the first storage unit 181 or the second storage unit 183, and a liquid volume control unit for controlling the volume of sample liquid stored in the first storage unit 181 or the second storage unit 183 based on the volume of sample liquid detected by the liquid volume detection means.

[0058] An example of the liquid volume detection means is a general-purpose liquid volume sensor disposed inside the first reservoir 181 or the second reservoir 183. The liquid volume control unit may include, for example, a pump disposed on the aforementioned inlet channel 182 or on the outlet channel through which the sample liquid after analysis by the ion analyzer 1 flows, and a sampling control unit that controls the operation of the pump. The sampling control unit preferably operates the pump continuously or intermittently so that the flow rate of the sample liquid flowing through the inlet channel 182 is, for example, 0.01 ml / min or more and 0.5 ml / min or less. The sampling control unit may, for example, perform the role of the aforementioned information processing circuit itself.

[0059] The ion analyzer 1 or the evaluation system 100 may further include a heat insulating member that maintains the temperature of the sample liquid S flowing upstream of the response glass 111 in the exhaust gas flow path L1 or through the inlet path 182 of the sampling unit 18. This heat insulating member is used to maintain the temperature of the produced water, which is the sample liquid flowing through the inlet path 182, so that it does not change significantly from the temperature in the first reservoir 181, thereby preventing water vapor in the exhaust gas from becoming liquid water.

[0060] The evaluation system 100 may further include, for example, a hydrogen consumption measurement device that measures the amount of hydrogen consumed in the fuel cell FC and a leak hydrogen measurement device that measures the amount of hydrogen leaked from the fuel cell FC, and may also include a control unit that controls the operation of these various measurement devices and analysis devices, a memory unit that stores measurement data output from these various measurement devices and analysis devices, and an alarm issuing unit that issues an alarm when the determination unit 2 determines, based on the measurement data, that an abnormality has occurred in the fuel cell FC. In this case, the determination unit 2 may evaluate the fuel cell FC by integrating information not only from the ion analysis device 1 but also from the hydrogen consumption measurement device, leak hydrogen measurement device, etc. to determine the operating status and state of deterioration of the fuel cell FC.

[0061] In the above-described embodiment, the ion analyzer analyzes effluent from a fuel cell, but it may also analyze effluent from a test specimen that discharges a small amount of liquid together with gas, such as a water electrolysis cell, a co-electrocatalyst, a methanation catalyst, an exhaust gas purification catalyst, or an oxidation catalyst, in addition to a fuel cell. Also, in the above-described embodiment, the evaluation system evaluates a fuel cell, but the test specimen evaluated by the evaluation system may also be a test specimen that discharges a small amount of liquid together with gas, such as a water electrolysis cell, a co-electrocatalyst, a methanation catalyst, an exhaust gas purification catalyst, or an oxidation catalyst, in addition to a fuel cell.

[0062] Specifically, water is produced from exhaust gas via an exhaust gas purification catalyst. Alternatively, water is produced by the reaction of carbon dioxide and hydrogen via a methanation catalyst (methanation reaction). Alternatively, water is produced by the reaction of ammonia and oxygen via an oxidation catalyst (ammonia reaction). Because the amount of water produced in these reactions is small, for example, the liquid volume control unit described above may be provided with a diluent inlet that introduces a diluent into the produced water. By introducing a diluent into the produced water via this diluent inlet, the component concentrations can be accurately measured even for small amounts of water generated from these test specimens.

[0063] In the above-described embodiment, the ion analyzer analyzes the effluent from a single-cell fuel cell or a small-volume fuel cell, but it is not limited to single-cell fuel cells or small-volume fuel cells, and may also analyze the effluent from a multi-cell fuel cell.

[0064] In the above-described embodiment, hydrogen gas and oxidant gas are supplied to the fuel cell, but when evaluating a test specimen other than a fuel cell, a gas other than hydrogen gas or oxidant gas may be supplied to the test specimen. Specifically, when the test specimen is an exhaust gas purification catalyst, exhaust gas may be supplied to the test specimen. Furthermore, when the test specimen is a methanation catalyst, carbon dioxide and hydrogen may be supplied to the test specimen. Furthermore, when the test specimen is an oxidation catalyst, ammonia and oxygen may be supplied to the test specimen. In addition, various modifications and combinations of the embodiments may be made as long as they do not deviate from the spirit of the present invention.

[0065] According to the present invention, it is possible to measure the ion concentration of a sample liquid even when an even smaller amount of sample liquid is supplied than in the past. As a result, it is possible to analyze changes in ion concentration in the sample liquid in real time with better response than when measuring sample liquid stored in a reservoir. Furthermore, because there is no need to dilute the sample liquid, it is possible to accurately measure the ion concentration in the sample liquid with as simple a configuration as possible.

[0066] REFERENCE SIGNS LIST 1 ion analyzer 11 measurement electrode 111 response glass (response section) 12 reference electrode 121 liquid junction 13 measurement flow path 14 calculation section 15 fixing mechanism 16 hydrophilic section 17 cooling section

Claims

1. An ion analyzer comprising a measurement electrode having a response part that responds to ions, a reference electrode having a liquid junction part, and a measurement channel in which the response part and the liquid junction part are disposed inside, the ion analyzer further comprising a hydrophilic part that connects the response part and the liquid junction part inside the measurement channel.

2. The ion analyzer according to claim 1, wherein the response part and the liquid junction part are disposed so as to face each other with the measurement channel therebetween.

3. The ion analyzer according to claim 1 or 2, wherein the response part and the liquid junction part are disposed so as to face each other with the measurement channel therebetween, and the liquid junction part is disposed on the downstream side of the response part.

4. The ion analyzer according to any one of claims 1 to 3, wherein the contact angle of the surface of the hydrophilic part that contacts the sample liquid is 90° or less.

5. The ion analyzer according to any one of claims 1 to 4, wherein the hydrophilic part is a hydrophilic surface layer provided on the inner wall of the measurement channel or a hydrophilic member disposed inside the measurement channel.

6. The ion analyzer according to any one of claims 1 to 5, wherein the hydrophilic part is a hydrophilic member provided in the measurement channel, and the hydrophilic member is disposed so as to contact both the response part and the liquid junction part.

7. The ion analyzer according to any one of claims 1 to 6, further comprising a fixing mechanism that fixes the measurement electrode and / or the reference electrode to the measurement channel with screws.

8. The ion analyzer according to any one of claims 1 to 7, further comprising a calculation unit that calculates the ion concentration in the sample liquid based on the potential difference between the measurement electrode and the reference electrode.

9. An evaluation system for analyzing ions contained in the exhaust gas discharged from a specimen, the evaluation system comprising the ion analyzer according to any one of claims 1 to 8.

10. The evaluation system according to claim 9, further comprising a cooling unit that cools the sample liquid flowing into the ion analyzer at a stage before the ion analyzer.

11. An ion analysis method for analyzing ions in a sample liquid flowing in a measurement channel, using a measurement electrode having a response part that responds to ions and a reference electrode having a liquid junction part, the ion analysis method comprising providing a hydrophilic part that connects the response part and the liquid junction part inside the measurement channel to electrically connect the response part and the liquid junction part.

12. An evaluation method for analyzing ions contained in exhaust gas discharged from a test specimen, which uses a measurement electrode having a response unit that responds to ions and a reference electrode having a liquid junction part to analyze the ions in the exhaust gas flowing in a measurement flow path, and provides a hydrophilic part inside the measurement flow path to connect the response unit and the liquid junction part to electrically connect the response unit and the liquid junction part.

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