Electrolytic solution analysis device and electrolytic solution analysis method

Abstract

To provide an electrolytic solution analysis device that measures the concentration of ions included in an electrolytic solution and can determine whether or not an ion selection film is separated from an underlying electrode layer.SOLUTION: An electrolytic solution analysis device in the present invention comprises: a substrate 31 extending in one direction; main electrode layers 43 and 44 that are provided on a main surface of the substrate 31 and that include a main base portion and a main extension portion; an ion selection film provided in contact with the main base portion so as to cover the main base portion; and an auxiliary electrode layer 48 that is provided on the main surface of the substrate 31 and that includes an auxiliary base portion 46 and an auxiliary extension portion. In a state where an electrolytic solution is in contact so as to cover the side at one end 31e of the substrate 31, separation-determining portions 11 and 14 acquire the potential of the main base portion through the main extension portion and acquire the potential of the auxiliary base portion 46 through the auxiliary extension portion. The separation-determining portions determine whether or not the ion selection film is separated from the main base portion on the basis of a potential difference between the acquired potential of the main base portion and the potential of the auxiliary base portion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to an electrolyte analyzer and an electrolyte analyzer method for measuring the concentration of ions contained in an electrolyte. [Background technology]

[0002] Conventionally, as an electrolytic solution analyzer of this type, a device comprising a sensor head and a main body to which the sensor head is mounted is known, as disclosed in, for example, Patent Document 1 (Japanese Patent No. 6127460). The sensor head has, on a substrate, a first ion-selective electrode that selects a first ion species and generates a potential corresponding to the concentration of the first ion species, and a second ion-selective electrode that selects a second ion species and generates a potential corresponding to the concentration of the second ion species. The main body is equipped with a CPU. With the sensor head mounted on the main body, the electrolyte (a standard solution with a known concentration ratio, or a target solution such as urine) is "contacted" to the region of the sensor head where the first and second ion-selective electrodes are provided, and the CPU calculates the potential difference between the first ion species and the second ion-selective electrode as the concentration ratio between the first ion species and the second ion species.

[0003] The first ion-selective electrode described above comprises a conductive first electrode layer and a first ion-selective film provided in contact with the first electrode layer so as to cover the first electrode layer. The second ion-selective electrode described above comprises a conductive second electrode layer and a second ion-selective film provided in contact with the second electrode layer so as to cover the second electrode layer. In a typical example, the first ion-selective film is impermeable to water and contains sodium ions (Na) as the first ion. + The second ion-selective membrane has the property of selectively permeating ) and water, and potassium ions (K) as the second ion. + It has the property of selectively permeating ). The first and second ion-selective membranes are formed by dropping solutions containing specific organic materials onto the first and second electrode layers, respectively, and allowing them to air dry. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 6127460 specification [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, if the user handles the sensor head improperly (for example, by rubbing the first and second ion-selective films), it is possible that part or all of the first and second ion-selective films may peel off from the first and second electrode layers.

[0006] Here, the first and second ion-selective films are typically transparent. Furthermore, the sensor head is designed to be small and disposable, and in Patent Document 1, the diameters of the first and second ion-selective films are set to a few millimeters. Therefore, for example, it is difficult for a user to visually determine whether the first and second ion-selective films have peeled away from the first and second electrode layers. When measurements are taken with the first and second ion-selective films in an unknown state, the reliability of the measurement results becomes questionable.

[0007] Therefore, the object of this invention is to provide an electrolyte analyzer and an electrolyte analyzer that can determine whether or not an ion-selective film has peeled off from the underlying electrode layer. [Means for solving the problem]

[0008] To solve the above problems, the electrolyte analyzer disclosed herein is An electrolyte analyzer for measuring the concentration of ions contained in an electrolyte, A substrate extending in one direction from one end to the other, On one of the pair of main surfaces of the substrate, a main electrode layer including a main base portion provided in a specific region on the side of the one end with respect to the one direction, and a main extending portion extending from the main base portion toward the side of the other end; In the specific region, an ion selective film having the property of selectively permeating the ions, provided in contact with the main base portion so as to cover the main base portion; On one of the pair of main surfaces of the substrate or on the other main surface, an auxiliary electrode layer including an auxiliary base portion provided in an auxiliary region different from the specific region on the side of the one end with respect to the one direction, and an auxiliary extending portion extending from the auxiliary base portion toward the side of the other end; The auxiliary electrode layer is disposed spaced apart from the main electrode layer; With the electrolyte in contact with the side of the one end of the substrate, the potential of the main base portion is acquired through the main extending portion, and the potential of the auxiliary base portion is acquired through the auxiliary extending portion, and based on the potential difference between the acquired potential of the main base portion and the potential of the auxiliary base portion, a peeling determination unit that determines whether the ion selective film has peeled off from the main base portion characterized by comprising.

[0009] Here, the "electrolyte" broadly refers to a liquid containing at least one ion species.

[0010] The "pair of main surfaces" of the substrate refers to a plate surface that spatially extends (for example, the front surface and the back surface), and is different from the end surface. <​​​​​​​Examples include the property of selectively permeating (water), or the property of not allowing water to pass through but selectively permeating potassium ions (K+).

[0013] To "contact" the electrolyte so as to cover one end of the substrate, the user (typically a subject) may sprinkle the electrolyte so as to cover one end of the substrate, or immerse one end of the substrate in the electrolyte.

[0014] The phrase "peeling off" the ion-selective film from the main base means that the ion-selective film is not in contact with the main base in such a way that it covers the main base, and includes not only the case where the entire ion-selective film is peeled off from the main base, but also the case where only a part of the ion-selective film is peeled off from the main base. If there is no "peeling," for example, when the electrolyte is applied so as to cover one end of the substrate, the electrolyte will not come into direct contact with the main base. On the other hand, if there is "peeling," when the electrolyte is applied so as to cover one end of the substrate, the electrolyte will come into direct contact with the main base.

[0015] In the electrolyte analyzer of this disclosure, the electrolyte is brought into contact with the substrate so as to cover one end of the substrate during use. The electrolyte then comes into contact with the ion-selective film (if present) on the main base portion and the auxiliary base portion so as to cover them together. In this state, the peeling determination unit acquires the potential of the main base portion via the main extension portion and the potential of the auxiliary base portion via the auxiliary extension portion. Here, as a phenomenon, if the ion-selective film is in contact with the main base portion so as to cover it (i.e., there is no "peeling" of the ion-selective film), a potential difference will be generated between the acquired potential of the main base portion and the potential of the auxiliary base portion, corresponding to the properties of the ion-selective film (the property of selectively permeating the ions). On the other hand, if the ion-selective film is peeled from the main base portion (even if only a part of the ion-selective film is peeled), no such potential difference will be generated between the acquired potential of the main base portion and the potential of the auxiliary base portion. Therefore, the peeling determination unit determines whether the ion-selective film has peeled off the main base based on the potential difference between the acquired potential of the main base and the potential of the auxiliary base. Specifically, if a potential difference corresponding to the properties of the ion-selective film (the property of selectively permeating the ions) is generated between the acquired potential of the main base and the potential of the auxiliary base, the peeling determination unit determines that the ion-selective film is covering the main base in contact with it, that is, the ion-selective film has not peeled off the main base (no film peeling). On the other hand, if no such potential difference is generated between the acquired potential of the main base and the potential of the auxiliary base, the peeling determination unit determines that the ion-selective film has peeled off the main base (film peeling present). In this way, this electrolyte analyzer can determine whether the ion-selective film has peeled off the main base, that is, the underlying electrode layer. Then, after confirming that there is no film peeling, the concentration of ions contained in the electrolyte can be measured. Therefore, the reliability of the measurement results can be increased.

[0016] In one embodiment of the electrolyte analyzer, The conductive material forming the main base portion is the same as the conductive material forming the auxiliary base portion. It is characterized by the following:

[0017] In this embodiment of the electrolyte analyzer, since the conductive material forming the main base is the same as the conductive material forming the auxiliary base, if the ion-selective film is peeled off from the main base (even if only a part of the ion-selective film is peeled off), the potential difference between the potential of the main base and the potential of the auxiliary base obtained will be substantially zero. Therefore, it is possible to accurately determine whether or not the ion-selective film is peeled off from the main base.

[0018] In one embodiment of the electrolyte analyzer, The peeling determination unit determines whether the ion-selective film has peeled off from the main base based on whether the potential difference is below a predetermined threshold. It is characterized by the following:

[0019] In this embodiment of the electrolyte analyzer, the peeling determination unit determines whether the ion-selective membrane has peeled off from the main base based on whether the potential difference is below a predetermined threshold. Therefore, the determination can be made with a simple process.

[0020] In one embodiment of the electrolyte analyzer, When it is determined that the ion-selective film has peeled off from the main base portion, the system is equipped with a notification unit that notifies of the occurrence of an abnormality indicating that the ion-selective film has peeled off. It is characterized by the following:

[0021] In this embodiment of the electrolyte analyzer, when it is determined that the ion-selective membrane has peeled off from the main base, the notification unit notifies that an abnormality has occurred, indicating that the ion-selective membrane has peeled off. Therefore, the user can know that normal measurement is impossible because the ion-selective membrane has peeled off. At this time, it is desirable that the electrolyte analyzer does not measure the ion concentration.

[0022] In one embodiment of the electrolyte analyzer, When it is determined that the ion-selective membrane has not peeled off the main base portion, the first calculation unit, triggered by this determination, calculates the concentration of the ions contained in the electrolyte based on the potential difference between the potential of the main base portion and the potential of the auxiliary base portion. It is characterized by the following:

[0023] In this embodiment of the electrolyte analyzer, when it is determined that the ion-selective membrane has not peeled off the main base, the first calculation unit uses this determination as a trigger to calculate the concentration of the ions contained in the electrolyte based on the potential difference between the potential of the main base and the potential of the auxiliary base. When measurement is performed after confirming that the ion-selective membrane has not peeled off the main base in this way, the reliability of the measurement result (ion concentration) can be increased.

[0024] In one embodiment of the electrolyte analyzer, The above electrolyte contains a first ionic species and a second ionic species that are different from each other. The above-mentioned specific region includes, on one of the main surfaces, first and second specific regions set apart from each other on the side of one end in one direction, The main electrode layer is located on one of the main surfaces of the substrate. It includes a first main base portion provided in the first specific region described above, and a first main extension portion extending from the first main base portion toward the other end, The second main base portion provided in the second specific region described above, and the second main extension portion extending from the second main base portion toward the other end, The first main base portion and the first main extension portion are spaced apart from the second main base portion and the second main extension portion. The above ion-selective membrane is In the first specific region described above, a first ion-selective membrane having the property of selectively permeating the first ion species is provided in contact with the first main base portion so as to cover the first main base portion, The second specific region includes a second ion-selective membrane that is provided in contact with the second main base portion so as to cover the second main base portion and has the property of selectively permeating the second ion species, The above peeling detection unit is, With the electrolyte in contact with the above-mentioned substrate so as to cover one end, the first potential indicated by the first main base portion and the second potential indicated by the second main base portion are acquired via the first and second main extension portions, respectively, and the third potential indicated by the auxiliary base portion is acquired via the auxiliary extension portion. Based on the potential difference between the obtained first potential and the third potential, it is determined whether the first ion-selective film has peeled off from the first main base portion. Similarly, based on the potential difference between the obtained second potential and the third potential, it is determined whether the second ion-selective film has peeled off from the second main base portion. It is characterized by the following:

[0025] In this embodiment of the electrolyte analyzer, the electrolyte is brought into contact with the substrate so as to cover one end of it during use. The electrolyte then comes into contact with the first ion-selective film (if present) on the first main base portion, the second ion-selective film (if present) on the second main base portion, and the auxiliary base portion, so as to cover them together. In this state, the peeling determination unit acquires the first potential indicated by the first main base portion and the second potential indicated by the second main base portion via the first and second main extension portions, respectively, and also acquires the third potential indicated by the auxiliary base portion via the auxiliary extension portion. Here, as a phenomenon, if the first ion-selective membrane is in contact with the first main base portion so as to cover it (i.e., if there is no "peeling" of the first ion-selective membrane), a potential difference will be generated between the obtained first potential and the third potential, corresponding to the properties of the first ion-selective membrane (its property of selectively permeating the first ion species). On the other hand, if the first ion-selective membrane is peeled off from the first main base portion (even if only a part of the first ion-selective membrane is peeled off), no such potential difference will be generated between the obtained first potential and the third potential. Furthermore, if the second ion-selective membrane is in contact with the second main base portion so as to cover it (i.e., if there is no "peeling" of the second ion-selective membrane), a potential difference will be generated between the acquired second potential and the third potential, corresponding to the properties of the second ion-selective membrane (its property of selectively permeating the second ion species). On the other hand, if the second ion-selective membrane is peeled from the second main base portion (even if only a part of the second ion-selective membrane is peeled), no such potential difference will be generated between the acquired second potential and the third potential. Therefore, the peeling determination unit determines whether the first ion-selective membrane is peeled from the first main base portion based on the potential difference between the acquired first potential and the third potential, and also determines whether the second ion-selective membrane is peeled from the second main base portion based on the potential difference between the acquired second potential and the third potential.Specifically, the peeling determination unit determines that if a potential difference corresponding to the properties of the first ion-selective membrane (the property of selectively permeating the first ion species) is generated between the acquired first potential and the third potential, the first ion-selective membrane is in contact with the first main base and covering the first main base, that is, the first ion-selective membrane has not peeled off the first main base. On the other hand, if no such potential difference is generated between the acquired first potential and the third potential, the peeling determination unit determines that the first ion-selective membrane has peeled off the first main base. In addition, the peeling determination unit determines that if a potential difference corresponding to the properties of the second ion-selective membrane (the property of selectively permeating the second ion species) is generated between the acquired second potential and the third potential, the second ion-selective membrane is in contact with the second main base and covering the second main base, that is, the second ion-selective membrane has not peeled off the second main base. On the other hand, if no such potential difference is generated between the acquired second potential and the third potential, the peeling determination unit determines that the second ion-selective membrane has peeled off the second main base. In this way, the electrolyte analyzer can determine whether the first ion-selective membrane has peeled off the first main base, and whether the second ion-selective membrane has peeled off the second main base.

[0026] In one embodiment of the electrolyte analyzer, When it is determined that the first ion-selective membrane is not detached from the first main base and the second ion-selective membrane is not detached from the second main base, the system includes a second calculation unit that, triggered by this determination, calculates the concentration ratio between the first ion species and the second ion species contained in the electrolyte based on the potential difference between the first potential and the second potential. It is characterized by the following:

[0027] In this embodiment of the electrolyte analyzer, when it is determined that the first ion-selective membrane is not detached from the first main base and the second ion-selective membrane is not detached from the second main base, the second calculation unit uses this determination as a trigger to calculate the concentration ratio between the first ion species and the second ion species contained in the electrolyte, based on the potential difference between the first potential and the second potential. In this way, when measurement is performed after confirming that the first and second ion-selective membranes are not detached from the first and second main bases, respectively, the reliability of the measurement result (the concentration ratio) can be increased.

[0028] In one embodiment of the electrolyte analyzer, A test specimen comprising the above-mentioned substrate, the above-mentioned main electrode layer, the above-mentioned ion-selective film, and the above-mentioned auxiliary electrode layer, The system comprises a main body to which the above-mentioned test piece is detachably attached, The above main unit is, The connector is provided with first, second, and third contact electrodes that contact the first main extension, the second main extension, and the auxiliary extension, respectively, when the other end of the above-mentioned test piece is inserted. It is equipped with the above-mentioned peeling detection unit and the above-mentioned second calculation unit. It is characterized by the following:

[0029] In this embodiment of the electrolyte analyzer, the apparatus comprises a test piece and a main body to which the test piece is detachably mounted. When the other end of the test piece is inserted into the connector of the main body, the first, second, and third contact electrodes of the connector come into contact with the first, second, and auxiliary extensions of the test piece, respectively. Therefore, the peeling determination unit can acquire the first potential, the second potential, and the third potential via the first, second, and third contact electrodes, respectively. Furthermore, the peeling determination unit can determine whether the first ion-selective film has peeled from the first main base based on the potential difference between the acquired first potential and the third potential, and whether the second ion-selective film has peeled from the second main base based on the potential difference between the acquired second potential and the third potential. Furthermore, the second calculation unit can calculate the concentration ratio between the first ion species and the second ion species contained in the electrolyte based on the potential difference between the first potential and the second potential. In addition, since the electrolyte analyzer of this embodiment includes the test piece and a main body to which the test piece is detachably attached, it is possible to use a test piece that is discarded after use and a new test piece is attached to the main body.

[0030] In one embodiment of the electrolyte analyzer, The above main unit is, A group of wires for connecting the first, second, and third contact electrodes of the above connector to the peeling detection unit and the second calculation unit, A changeover switch inserted into the above wiring group, It includes a switching control unit, The above switching control unit controls the above switching switch, For the peeling detection unit described above, a first connection state is created in which the first contact electrode and the third contact electrode of the connector are electrically connected to the peeling detection unit via the wiring group, and a second connection state is created in which the second contact electrode and the third contact electrode are electrically connected to the peeling detection unit via the wiring group, and further, For the second calculation unit described above, a third connection state is created in which the first contact electrode and the second contact electrode of the connector are connected to the second calculation unit via the wiring group. It is characterized by the following:

[0031] In this embodiment of the electrolyte analyzer, the control unit controls the changeover switch to sequentially create a first connection state in which the first contact electrode and the third contact electrode of the connector are electrically connected to the peeling determination unit via the wiring group, and a second connection state in which the second contact electrode and the third contact electrode are electrically connected to the peeling determination unit via the wiring group. Therefore, in the first connection state, the peeling determination unit can acquire the first potential and the third potential via the first and third contact electrodes, respectively, and determine whether the first ion-selective film has peeled from the first main base based on the potential difference between the acquired first potential and the third potential. Next, in the second connection state, the peeling determination unit acquires the second potential and the third potential, respectively, via the second and third contact electrodes, and can determine whether the second ion-selective film has peeled off from the second main base based on the potential difference between the acquired second potential and the third potential. Furthermore, the control unit controls the changeover switch to create a third connection state for the second calculation unit, connecting the first contact electrode and the second contact electrode of the connector to the second calculation unit via the wiring group. Therefore, in the third connection state, the second calculation unit acquires the first potential and the second potential, respectively, via the first and second contact electrodes, and can calculate the concentration ratio between the first ion species and the second ion species contained in the electrolyte based on the potential difference between the acquired first potential and the second potential.

[0032] In one embodiment of the electrolyte analyzer, The auxiliary electrode layer is provided on one of the pair of main surfaces. It is characterized by the following:

[0033] In this embodiment of the electrolyte analyzer, the auxiliary electrode layer is provided on one of the pair of main surfaces. Therefore, when forming the electrode layer during the manufacturing stage of this electrolyte analyzer, the main electrode layer and the auxiliary electrode layer can be formed simultaneously on the one main surface, for example, by screen printing. Furthermore, when using this electrolyte analyzer, if the user brings the electrolyte into contact with only the one main surface so as to cover one end of the substrate, the peeling determination unit can determine whether or not the ion-selective film has peeled off from the main base.

[0034] In another context, the electrolyte analysis method of this disclosure is An electrolyte analysis method for measuring the concentration of ions contained in an electrolyte, A substrate extending in one direction from one end to the other, On one of the pair of main surfaces of the above substrate, a main electrode layer is provided, which includes a main base portion provided in a specific region on one end side with respect to the above one direction, and a main extension portion extending from the main base portion toward the other end side. In the above-mentioned specific region, an ion-selective membrane having the property of selectively permeating the ions is provided in contact with the main base portion so as to cover the main base portion, The substrate comprises an auxiliary electrode layer including an auxiliary base portion provided in an auxiliary region different from the specific region on one end side with respect to one direction, on one of the pair of main surfaces of the substrate, or on the other main surface, on one end side of the pair of main surfaces, and an auxiliary extension portion extending from the auxiliary base portion to the other end side. The auxiliary electrode layer is positioned at a distance from the main electrode layer. The above electrolyte analysis method is: With the electrolyte in contact with the above-mentioned substrate so as to cover one end, the potential of the main base portion is obtained via the main extension portion, and the potential of the auxiliary base portion is obtained via the auxiliary extension portion. Based on the potential difference between the potential of the main base portion and the potential of the auxiliary base portion obtained, it is determined whether or not the ion-selective film has peeled off from the main base portion. It is characterized by the following:

[0035] According to the electrolyte analysis method disclosed herein, it is possible to determine whether or not the ion-selective film has peeled off from the main base portion, i.e., the underlying electrode layer. [Effects of the Invention]

[0036] As is clear from the above, the electrolyte analyzer and electrolyte analyzer method of this disclosure can determine whether or not the ion-selective film has peeled off from the underlying electrode layer. [Brief explanation of the drawing]

[0037] [Figure 1] Figure 1(A) is a diagram showing the schematic configuration of an electrochemical sensor as an electrolyte analyzer according to one embodiment of the present invention. Figure 1(B) is a schematic diagram showing the main body of the electrolyte analyzer viewed from an oblique angle. [Figure 2] Figure 2(A) shows the planar layout of the electrochemical sensor containing the test specimen for electrolyte analysis. Figure 2(B) is a schematic diagram showing the cross-section of the electrochemical sensor in Figure 2(A). [Figure 3] This diagram shows the block configuration of the electrochemical sensor described above. [Figure 4] This diagram shows the flow chart of an electrolyte analysis method in which a subject, acting as a user, measures the concentration ratio between sodium ions and potassium ions in urine, which serves as the electrolyte, using the electrochemical sensor described above. [Figure 5] Figure 5(A) shows a configuration in which the standard solution is in contact with one end of the electrolyte analysis test piece, when there is no film peeling on the test piece. Figure 5(B) illustrates the changes in potential difference between the sodium ion-sensitive electrode and the auxiliary electrode, and between the potassium ion-sensitive electrode and the auxiliary electrode, in the configuration shown in Figure 5(A). [Figure 6]Figure 6(A) shows a configuration in which the standard solution is in contact with one end of the electrolyte analysis specimen, where the specimen has Na film peeling but no K film peeling. Figure 6(B) illustrates the changes in potential difference between the sodium ion-sensitive electrode and the auxiliary electrode, and between the potassium ion-sensitive electrode and the auxiliary electrode, in the configuration shown in Figure 6(A). [Figure 7] Figure 7(A) shows a configuration in which the standard solution is in contact with one end of the electrolyte analysis specimen, where the specimen has K film peeling but no Na film peeling. Figure 7(B) illustrates the changes in potential difference between the sodium ion-sensitive electrode and the auxiliary electrode, and between the potassium ion-sensitive electrode and the auxiliary electrode, in the configuration shown in Figure 7(A). [Figure 8] This diagram illustrates the change in potential difference between the sodium ion-sensitive electrode and the potassium ion-sensitive electrode from the start of calibration with the standard solution to the completion of urine measurement in the above-described electrolyte analysis method flow. [Modes for carrying out the invention]

[0038] The embodiments of this invention will now be described in detail with reference to the drawings.

[0039] (Outline configuration of an electrochemical sensor) Figure 1(A) shows a schematic configuration of an electrochemical sensor 90 as an electrolyte analyzer according to one embodiment of the present invention. For ease of understanding, in addition to Figure 1(A), the XYZ Cartesian coordinate system is also shown in Figures 1(B), 2(A), and 2(B) described later.

[0040] This electrochemical sensor 90 comprises, broadly speaking, a test piece 30 for electrolyte analysis (hereinafter simply referred to as "test piece") and a main body 10 to which this test piece 30 is attached. This test piece 30 is used to measure the concentration ratio between a first ion species and a second ion species contained in the electrolyte to be measured. In this example, the electrolyte to be measured is urine, the first ion species is sodium ions, and the second ion species is potassium ions. Furthermore, a standard solution containing sodium ions and potassium ions in a predetermined concentration ratio (i.e., Na / K ratio) is used as the electrolyte for calibration.

[0041] (Construction of the test specimen) Figure 2(A) shows the planar layout of the test specimen 30. Figure 2(B) schematically shows the cross-section of Figure 2(A), particularly the cross-section of the electrode portion. As can be seen from these figures, the test specimen 30 comprises a single substrate 31 that extends elongated in the X direction from one end 31e to the other end 31f, a sodium ion-sensitive electrode 41 as a first ion-sensitive electrode provided in a circular first specific region 51w1 on the surface 31a, which is one main surface of the substrate 31, on the side of the one end 31e with respect to the X direction, a potassium ion-sensitive electrode 42 as a second ion-sensitive electrode provided in a circular second specific region 51w2 that is closer to the one end 31e than the first specific region 51w1, and first and second main electrode layers 43 and 44 that extend from the sodium ion-sensitive electrode 41 and potassium ion-sensitive electrode 42 toward the other end 31f, respectively.

[0042] Furthermore, "the side of one end 31e" refers to the side of the two ends 31f that is closer to one end 31e in the X direction. Similarly, "the side of the other end 31f" refers to the side of the two ends 31f that is closer to the other end 31f in the X direction.

[0043] The first main electrode layer 43 has a circular base portion 43a as a first main base portion provided in a first specific region 51w1, a lead portion 43b that extends elongatedly from the base portion 43a toward the other end 31f, and an electrode pad portion 43c that is wider than the lead portion 43b and is provided adjacent to the lead portion 43b toward the other end 31f. The lead portion 43b and the electrode pad portion 43c constitute the first main extension portion. The second main electrode layer 44 has a circular base portion 44a as a second main base portion provided in a second specific region 51w2, a lead portion 44b that extends elongatedly from the base portion 44a toward the other end 31f, and an electrode pad portion 44c that is wider than the lead portion 44b and is provided adjacent to the lead portion 44b toward the other end 31f. The lead portion 44b and the electrode pad portion 44c constitute a second main extension. The first main electrode layer 43 and the second main electrode layer 44 are spaced apart from each other.

[0044] As can be seen in Figure 2(B), the sodium ion-sensitive electrode 41 consists of a base portion 43a of the first main electrode layer 43 and a sodium ion-selective membrane 41i, which is provided in contact with the base portion 43a so as to cover the base portion 43a. The potassium ion-sensitive electrode 42 consists of a base portion 44a of the second main electrode layer 44 and a potassium ion-selective membrane 42i, which is provided in contact with the base portion 44a so as to cover the base portion 44a. The sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 come into contact with the electrolyte to be measured (in this example, urine) and generate a first potential (denoted as E1) corresponding to the concentration of sodium ions and a second potential (denoted as E2) corresponding to the concentration of potassium ions, respectively.

[0045] Furthermore, as shown in Figure 2(A), the test specimen 30 includes an auxiliary electrode layer 48 positioned on the surface 31a of the substrate 31, spaced apart from the first and second main electrode layers 43 and 44. The auxiliary electrode layer 48 has an auxiliary electrode 46 as an auxiliary base portion provided in a circular auxiliary region 51w3, a lead portion 48b extending elongatedly from the auxiliary electrode 46 toward the other end 31f, and an electrode pad portion 48c wider than the lead portion 48b, which is connected to the lead portion 48b and provided toward the other end 31f. In this example, the auxiliary electrode 46 comes into contact with a standard solution (or urine) to generate a third potential (let's call this E3).

[0046] In this example, the auxiliary region 51w3 is positioned on the surface 31a of the substrate 31 between one end 31e and the second specific region 51w2 in the X direction, and between the first specific region 51w1 and the second specific region 51w2 in the width direction (Y direction).

[0047] Accordingly, on the surface 31a of the substrate 31, the lead portions 43b, 48b, and 44b are arranged in this order, spaced apart from each other, from the +Y side to the -Y side. Correspondingly, along the other end 31f of the substrate 31, the electrode pad portions 43c, 48c, and 44c are arranged in this order, spaced apart from each other.

[0048] An insulating film 51 is provided on the surface 31a of the substrate 31 as a protective layer. The insulating film 51 covers the surface from one end 31e in the X direction to approximately the electrode pad portions 43c, 48c, and 44c. Therefore, the lead portions 43b, 48b, and 44b are each protected by the insulating film 51. On the other hand, the electrode pad portions 43c, 48c, and 44c are exposed from the insulating film 51 and are electrically connected to the connector of the main body, which will be described later.

[0049] On the surface 31a of the substrate 31, the insulating film 51 has four circular openings that penetrate in the thickness direction (Z direction) and define the first specific region 51w1, the second specific region 51w2, and the auxiliary region 51w3, respectively (represented by the same symbols 51w1, 51w2, and 51w3 as the regions they define). The effective regions (functional regions) of the sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 are defined by the size of the openings 51w1 and 51w2, respectively (in this example, each with a diameter of approximately 4 mm). In this example, the size of the opening 51w3 is also set to a diameter of approximately 4 mm.

[0050] The substrate 31 is made of an insulating material such as PET (polyethylene terephthalate), glass, silicon, polyimide film, glass epoxy, polycarbonate, or acrylic. Therefore, the surface 31a (and back surface 31b) also have insulating properties. In this example, the dimensions of the substrate 31 are set to approximately 60-100 mm in the X direction (longitudinal direction), approximately 15-30 mm in the Y direction (width direction), and approximately 200 μm in the Z direction (thickness direction).

[0051] The first main electrode layer 43, the second main electrode layer 44, and the auxiliary electrode layer 48 are made of the same conductive material, such as Pt, Ag, Au, Ir, C, or IrO2. The thickness of the first main electrode layer 43, the second main electrode layer 44, and the auxiliary electrode layer 48 is approximately 10 μm.

[0052] The insulating film 51 consists of a photocurable or thermocurable insulating resist, or an insulating seal, sheet, tape, etc. The thickness of the insulating film 51 is approximately 30 μm to 100 μm.

[0053] In this example, the material solution used for forming the sodium ion selective membrane 41i is a solution obtained by dissolving Bis(12-corwn-4), polyvinyl chloride (PVC), 2-nitrophenyl octyl ether (NPOE), and potassium tetrakis(4-chlorophenyl)borate (K-TCPB) in tetrahydrofuran (THF). In this example, the material solution used for forming the potassium ion selective membrane 42i is a solution obtained by dissolving Bis(benzo-15-crown-5), PVC, NPOE, and K-TCPB in THF. These material solutions are dried and cured during the manufacturing process.

[0054] The manufacturing process for the test specimen 30 is as follows. First, a first main electrode layer 43, a second main electrode layer 44, and an auxiliary electrode layer 48 are simultaneously formed on the surface 31a of the substrate 31, for example by a screen printing method. Next, an insulating film 51 is formed on top of these, for example by a screen printing method. At this time, the insulating film 51 is formed in such a state that the electrode pad portions 43c, 48c, and 44c are exposed, and three openings 51w1, 51w2, and 51w3 are formed to expose the base portion 43a of the first main electrode layer 43, the base portion 44a of the second main electrode layer 44, and the auxiliary electrode 46, respectively. Next, a material solution for forming a sodium ion selective film 41i is applied to the opening 51w1 on the surface 31a of the substrate 31, for example by an inkjet printing method. Then, the applied material solution is dried and cured to form a sodium ion selective film 41i in the region corresponding to the opening 51w1. The base portion 43a and the sodium ion selective film 41i constitute the sodium ion sensitive electrode 41. Next, a material solution for forming the potassium ion selective film 42i is applied to the opening 51w2 on the surface 31a of the substrate 31, for example, by inkjet printing. The applied material solution is then dried and cured to form the potassium ion selective film 42i in the region corresponding to the opening 51w2. The base portion 44a and the potassium ion selective film 42i constitute the potassium ion sensitive electrode 42. The formed (cured) sodium ion selective film 41i and potassium ion selective film 42i are transparent.

[0055] (Main unit configuration) Figure 1(B) schematically shows the main body 10 of the electrochemical sensor 90 viewed from an oblique angle. In this example, the main body 10 has an elongated rectangular prism shape that is meant to be held in the user's hand. As a result, this electrochemical sensor 90 is configured as a handheld device used by the user holding the main body 10 in their hand.

[0056] The main unit 10 comprises a housing 10s with a roughly rectangular prism-shaped outer wall, a display unit 20 as a display screen provided approximately in the center of the front surface (+Z side surface) 10f of the housing 10s, an operation unit 13 provided on the front surface 10f at a position +X side of the display unit 20, and a connector 21 provided on the -X side end surface 10t of the housing 10s. In this example, the display unit 20 is made of an LCD (liquid crystal display element) and displays various information such as calculation results from the control unit 11 (see Figure 3), which will be described later. In this example, the operation unit 13 includes three push-button switches: a power switch 13a for turning the power of the electrochemical sensor 90 on and off, a calibration switch 13b for inputting an instruction to start calibration using an electrolyte (standard solution) with a known concentration ratio between sodium ions and potassium ions, and a measurement switch 13c for inputting an instruction to start calculating the concentration ratio between sodium ions and potassium ions in urine, which is the liquid to be measured.

[0057] The connector 21 has a slot 22 that opens toward the -X side to removably receive the test piece 30. Inside the slot 22, three contact electrodes 21a, 21c, and 21b, each made of an L-shaped bent leaf spring, are provided at positions corresponding to the electrode pad portions 43c, 48c, and 44c of the test piece 30, respectively. These contact electrodes are appropriately referred to as the first contact electrode 21a, the third contact electrode 21c, and the second contact electrode 21b. As shown in Figure 1(A), when the user inserts the other end 31f of the test piece 30 into the slot 22 in the direction indicated by the arrow X1, the electrode pad portions 43c, 48c, and 44c come into contact with the corresponding contact electrodes 21a, 21c, and 21b, respectively, and conduction occurs. As a result, the first potential E1 generated by the sodium ion-sensitive electrode 41 and the second potential E2 generated by the potassium ion-sensitive electrode 42 of the test piece 30 are transmitted to the first and second contact electrodes 21a and 21b, respectively, via the first and second main electrode layers 43 and 44, and can be input to the main body 10. In addition, the third potential E3 generated by the auxiliary electrode 46 is transmitted to the third contact electrode 21c via the auxiliary electrode layer 48 (particularly the lead portion 48b and the electrode pad portion 48c) and can be input to the main body 10.

[0058] As shown in Figure 3, the main unit 10 houses the display unit 20, operation unit 13, and connector 21 mentioned above, as well as a control unit 11, a potential difference measurement unit 12, a peel detection unit 14, a storage unit 18, a communication unit 19, and a power supply unit 25. The control unit 11 consists of an MCU (Micro Controller Unit) including a CPU (Central Processing Unit) that operates by software, and controls the operation of the entire electrochemical sensor 90 as described later. The potential difference measurement unit 12 has two input units 12a and 12b, and amplifies the potential difference between these input units 12a and 12b and inputs it to the control unit 11. Similarly, the peel detection unit 14 has two input units 14a and 14b, and amplifies the potential difference between these input units 14a and 14b and inputs it to the control unit 11. The storage unit 18 consists of a semiconductor memory and stores program data for controlling the electrochemical sensor 90, setting data for setting various functions of the electrochemical sensor 90, and measurement data. The memory unit 18 is used as work memory when a program is executed. The communication unit 19 transmits information from the control unit 11 (in this example, measurement data) to other devices (for example, a server) via the network 900. It also receives information from other devices via the network 900 and passes it on to the control unit 11. The power supply unit 25 supplies power to the control unit 11, the display unit 20, the potential difference measurement unit 12, the peeling detection unit 14, the memory unit 18, the communication unit 19, and other parts of the main unit 10.

[0059] Furthermore, the main unit 10 houses a wiring group 71 for connecting the three contact electrodes 21a, 21c, and 21b of the connector 21 to the potential difference measurement unit 12 and the peel detection unit 14, and a changeover switch 80 inserted into the wiring group 71. The wiring group 71 includes wires 71a, 71c, and 71b that are electrically connected to the three contact electrodes 21a, 21c, and 21b of the connector 21, respectively, and wires 71u, 71v, 71w, and 71x that are electrically connected to the input sections 12a, 12b of the potential difference measurement unit 12 and the input sections 14a, 14b of the peel detection unit 14, respectively. Note that wires 71c and 71x are a single common wire.

[0060] In this example, the changeover switch 80 has two switching units 80a and 80b that can be switched independently of each other by a switching control signal Ctrl from the control unit 11. In this example, switching unit 80a can be switched between a normal position (shown by a solid line) that creates a conductive path 81 between wiring 71a and wiring 71u, and an active position (shown by a dashed line) that creates a conductive path 82 between wiring 71a and wiring 71w. Similarly, switching unit 80b can be switched between a normal position (shown by a solid line) that creates a conductive path 83 between wiring 71b and wiring 71v, and an active position (shown by a dashed line) that creates a conductive path 84 between wiring 71b and wiring 71w. In this example, three connection states are planned: a first connection state in which switching unit 80a is in the active position and switching unit 80b is in the normal position; a second connection state in which switching unit 80a is in the normal position and switching unit 80b is in the active position; and a third connection state in which both switching units 80a and 80b are in the normal position. However, in this electrochemical sensor 90, a connection state in which both switching units 80a and 80b are in the active position is not planned.

[0061] (First connection state) In the first connection state, where the switching unit 80a is in the active position and the switching unit 80b is in the normal position, the contact electrode 21a of the connector 21 is electrically connected to the input unit 14a of the peel detection unit 14 via the wiring 71a, the conductive path 82, and the wiring 71w. The contact electrode 21c of the connector 21 is electrically connected to the input unit 14b of the peel detection unit 14 via the wiring 71c (i.e., the wiring 71x). Therefore, the peel detection unit 14 receives the first potential E1 generated by the sodium ion sensitive electrode 41 at the input unit 14a and the third potential E3 generated by the auxiliary electrode 46 at the input unit 14b, and the potential difference between the first potential E1 and the third potential E3 (this is called ΔE) 13 This can be amplified and input to the control unit 11. Then, as will be described later, the control unit 11 acts as a peeling determination unit and this potential difference ΔE13 Based on this, it is possible to determine whether or not the sodium ion selective film 41i, which forms the sodium ion sensitive electrode 41, has peeled off from the base portion 43a.

[0062] (Second connection state) In the second connection state, where the switching unit 80a is in the normal position and the switching unit 80b is in the active position, the contact electrode 21b of the connector 21 is electrically connected to the input unit 14a of the peel detection unit 14 via the wiring 71b, the conductive path 84, and the wiring 71w. The contact electrode 21c of the connector 21 is electrically connected to the input unit 14b of the peel detection unit 14 via the wiring 71c (i.e., the wiring 71x). Therefore, the peel detection unit 14 receives the second potential E2 generated by the potassium ion sensitive electrode 42 at the input unit 14a and the third potential E3 generated by the auxiliary electrode 46 at the input unit 14b, and the potential difference between the second potential E2 and the third potential E3 (this is called ΔE) 23 This can be amplified and input to the control unit 11. Then, as will be described later, the control unit 11 acts as a peeling determination unit and this potential difference ΔE 23 Based on this, it is possible to determine whether or not the potassium ion selective film 42i, which forms the potassium ion sensitive electrode 42, has peeled off from the base portion 44a.

[0063] Here, the method by which the control unit 11 determines the presence or absence of delamination of the sodium ion selective membrane 41i (referred to as "Na membrane delamination") and the presence or absence of delamination of the potassium ion selective membrane 42i (referred to as "K membrane delamination") is based on the following phenomenon confirmed by the inventors through experiments.

[0064] For example, as shown in Fig. 5(A), assume that there is no film peeling on the test piece 30. In this state, more specifically, so as to cover the side of one end 31e of the substrate 31, that is, to integrally cover the region A1 (shown by a broken line in Fig. 5(A)) including at least the auxiliary electrode 46, the sodium ion-sensitive electrode 41, and the potassium ion-sensitive electrode 42. In this example, assume that a standard solution as an electrolytic solution is brought into contact. Here, the standard solution has a known concentration ratio Mr (in this example, Mr = 4.0; the same applies hereinafter) between the concentration of sodium ions and the concentration of potassium ions. Then, as a phenomenon, as shown in Fig. 5(B), the potential difference ΔE between the first potential E1 generated by the sodium ion-sensitive electrode 41 and the third potential E3 generated by the auxiliary electrode 46 13 ((shown by a broken line in Fig. 5(B); the same applies in Figs. 6(B) and 7(B)) converges to a value (in this example, about 0.03 [V]) corresponding to the concentration of sodium ions in the standard solution several seconds (4 seconds to 5 seconds) after contact. Also, the potential difference ΔE between the second potential E2 generated by the potassium ion-sensitive electrode 42 and the third potential E3 generated by the auxiliary electrode 46 23 (shown by a solid line in Fig. 5(B); the same applies in Figs. 6(B) and 7(B)) converges to a value (in this example, about 0.18 [V]) corresponding to the concentration of potassium ions in the standard solution several seconds (4 seconds to 5 seconds) after contact. Note that the noise level is sufficiently smaller than 0.01 [V] (the same applies hereinafter).

[0065] Instead, for example, as shown in Fig. 6(A), assume that there is Na film peeling on the test piece 30 but no K film peeling. As a result, assume that the base portion 43a of the sodium ion-sensitive electrode 41 is exposed. In this state, assume that a standard solution as an electrolytic solution is brought into contact so as to cover the side of one end 31e of the substrate 31 (the region A1 shown by a broken line in Fig. 6(A)). Then, as a phenomenon, as shown in Fig. 6(B), the potential difference ΔE between the first potential E1 generated by the sodium ion-sensitive electrode 41 and the third potential E3 generated by the auxiliary electrode 46 13The potential becomes approximately zero (<0.01[V]) within about 2 seconds from the time of contact. This is because the sodium ion-sensitive electrode 41 and the auxiliary electrode 46 are conductive due to the standard solution, and as previously described, the first main electrode layer 43 (including the base portion 43a) and the auxiliary electrode layer 48 (including the auxiliary electrode 46) are made of the same conductive material. This phenomenon occurs not only when the entire sodium ion-selective film 41i is peeled from the base portion 43a, but also when only a part of the sodium ion-selective film 41i is peeled from the base portion 43a. On the other hand, the potential difference ΔE between the second potential E2 generated by the potassium ion-sensitive electrode 42 and the third potential E3 generated by the auxiliary electrode 46 23 As shown in Figure 5(B), the voltage converges to a value corresponding to the concentration of potassium ions in the standard solution (approximately 0.18 [V] in this example) a few seconds (4 to 5 seconds) after contact.

[0066] Furthermore, as shown in Figure 7(A), for example, the test piece 30 has K film peeling but no Na film peeling. This exposes the base portion 44a of the potassium ion-sensitive electrode 42. In this state, a standard solution is applied as an electrolyte so as to cover one end 31e of the substrate 31 (region A1 shown by the dashed line in Figure 7(A)). Then, as a phenomenon, as shown in Figure 7(B), a potential difference ΔE is generated between the second potential E2 generated by the potassium ion-sensitive electrode 42 and the third potential E3 generated by the auxiliary electrode 46. 23 The potential becomes approximately zero (<0.01[V]) within about 2 seconds from the time of contact. This is because the potassium ion-sensitive electrode 42 and the auxiliary electrode 46 are conductive due to the standard solution, and as previously described, the second main electrode layer 44 (including the base portion 44a) and the auxiliary electrode layer 48 (including the auxiliary electrode 46) are made of the same conductive material. This phenomenon occurs not only when the entire potassium ion-selective film 42i is peeled from the base portion 44a, but also when only a part of the potassium ion-selective film 42i is peeled from the base portion 44a. On the other hand, the potential difference ΔE between the first potential E1 generated by the sodium ion-sensitive electrode 41 and the third potential E3 generated by the auxiliary electrode 46 13As shown in Figure 5(B), the voltage converges to a value corresponding to the concentration of sodium ions in the standard solution (approximately 0.03 [V] in this example) a few seconds (4 to 5 seconds) after contact.

[0067] Furthermore, if both Na film peeling and K film peeling are present on test specimen 30, the potential difference ΔE 13 and potential difference ΔE 23 In all cases, the voltage drops to approximately zero (<0.01[V]) within about 2 seconds of contact.

[0068] The potential difference ΔE in each of the above cases 13 ,ΔE 23 This can be summarized as shown in Table 1 below. (Table 1) TIFF2023120955000002.tif57144

[0069] Therefore, the control unit 11 acts as a peeling determination unit, for example, determining the potential difference ΔE 5 seconds after contact with the standard solution. 13 Based on whether the potential difference ΔEth is below a predetermined threshold ΔEth (in this example, ΔEth = 0.01 [V]), it can be determined whether the sodium ion selective membrane 41i has peeled off from the base portion 43a. Similarly, the potential difference ΔE 5 seconds after contact with the standard solution can be determined. 23 Based on whether the potential difference ΔE is below the threshold ΔEth (=0.01[V]), it can be determined whether the potassium ion selective film 42i has peeled off from the base portion 44a. In this way, the control unit 11 can determine whether the potential difference ΔE 13 ΔE 23 The determination is made based on whether each of the following is below the threshold ΔEth, so the determination can be made with a simple process. Also, if there is Na film peeling or K film peeling, the potential difference ΔE 13 ΔE 23 Since these values ​​become approximately zero, the presence or absence of Na film peeling and K film peeling can be determined with high accuracy.

[0070] (Third connection state) In the third connection state, where both switching units 80a and 80b of the changeover switch 80 shown in Figure 3 are in the normal position, the contact electrode 21a of the connector 21 is electrically connected to the input unit 12a of the potential difference measurement unit 12 via the wiring 71a, the conductive path 81, and the wiring 71u. At the same time, the contact electrode 21b of the connector 21 is electrically connected to the input unit 12b of the potential difference measurement unit 12 via the wiring 71b, the conductive path 83, and the wiring 71v. Therefore, the potential difference measurement unit 12 receives the first potential E1 generated by the sodium ion sensitive electrode 41 at the input unit 12a and the second potential E2 generated by the potassium ion sensitive electrode 42 at the input unit 12b, and can amplify the potential difference between the first potential E1 and the second potential E2 (let's call this ΔE).

[0071] Furthermore, the control unit 11 acts as a second calculation unit and can use the potential difference ΔE amplified by the potential difference measurement unit 12 to calculate the concentration ratio (C1 / C2) between the sodium ion concentration C1 and the potassium ion concentration C2 contained in the electrolyte solution to be measured (in this example, urine).

[0072] In this electrochemical sensor 90, the concentration ratio (C1 / C2) between the concentration of sodium ions C1 and the concentration of potassium ions C2 contained in the liquid to be measured is determined by the following principle. Here, the sensitivity S1 and selectivity k1 of the sodium ion-sensitive electrode 41 are set to match the sensitivity S2 and selectivity k2 of the potassium ion-sensitive electrode 42, respectively. That is, S1-S2≈0 and k1-k2≈0. In that case, as disclosed in Patent Document 1 (Japanese Patent No. 6127460), the potential difference ΔE between the sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 is expressed in a simplified form as shown in the following equation (Eq.1). ΔE=E1 0 -E2 0 +S1log(C1 / C2) …(Eq.1) Here, E1 0 -E2 0is assumed to be a constant and predetermined. Therefore, by measuring ΔE for an electrolyte (standard solution) with a known concentration ratio Mr between sodium and potassium ions, and determining the sensitivity S1 as a parameter, the concentration ratio Ms (=C1 / C2) between sodium and potassium ions in the electrolyte to be measured can be calculated based on equation (Eq.1) by measuring the potential difference ΔE for the electrolyte to be measured (in this example, urine).

[0073] (Electrolyte analysis method) Figure 4 shows the flow chart of an electrolyte analysis method in which a subject, acting as a user, uses an electrochemical sensor 90 to measure the concentration ratio between sodium ions and potassium ions in urine, which serves as the electrolyte.

[0074] Prior to this, the user has attached the test piece 30 to the main body 10 by inserting the other end 31f of the test piece 30 into the slot 22 of the main body 10 as indicated by arrow X1, as shown in Figure 1. This state is called the "attached state". As previously described, in this attached state, the electrode pad portions 43c, 48c, and 44c of the test piece 30 are in contact with the contact electrodes 21a, 21c, and 21b of the connector 21, respectively, and are electrically connected.

[0075] Next, with the device installed, the user presses the power switch 13a of the main unit 10 to turn it on (step S101 in Figure 4). Then, the power supply unit 25 shown in Figure 3 starts supplying power to each part of the main unit 10. In this example, the control unit 11 displays "ON" on the display unit 20 as a string indicating that the power has been turned on. At the same time, the control unit 11 uses the switching control signal Ctrl to maintain both the switching parts 80a and 80b of the changeover switch 80 in the normal position. As a result, the conductive paths 81 and 83 of the changeover switch 80 are turned on (created).

[0076] Next, the user brings the standard solution, which serves as the electrolyte, into contact with one end 31e of the test piece 30 (substrate 31) (for example, region A1 shown by the dashed line in Figure 5). In this example, since the sodium ion-sensitive electrode 41, potassium ion-sensitive electrode 42, and auxiliary electrode 46 are all provided on the surface 31a of the substrate 31, the user only needs to bring the standard solution into contact with region A1 on the surface 31a of the substrate 31 (this allows for subsequent processing). The operation of bringing the standard solution into contact with region A1 can be done, for example, by sprinkling the standard solution on one end 31e of the test piece 30, or by immersing one end 31e of the test piece 30 in the standard solution in a container (not shown). Then, the user presses the calibration switch 13b to turn it on (step S102 in Figure 4).

[0077] Then, the control unit 11 acts as a switching control unit and controls the changeover switch 80 shown in Figure 3 with the switching control signal Ctrl to switch the switching unit 80a to the active position and maintain the switching unit 80b in the normal position. This turns on the conduction path 82 instead of the conduction path 81 and keeps the conduction path 83 on, creating the first connection state (step S103 in Figure 4). In this first connection state, the contact electrode 21a of the connector 21 is electrically connected to the input section 14a of the peel detection unit 14 via the wiring 71a, conduction path 82, and wiring 71w. The contact electrode 21c of the connector 21 is electrically connected to the input section 14b of the peel detection unit 14 via the wiring 71c (i.e., wiring 71x). Therefore, the peel detection unit 14 receives the first potential E1 generated by the sodium ion-sensitive electrode 41 at the input unit 14a, and the third potential E3 generated by the auxiliary electrode 46 at the input unit 14b, and the potential difference ΔE between the first potential E1 and the third potential E3 13 The signal is amplified and input to the control unit 11. The control unit 11 monitors the potential difference ΔE until 5 seconds have elapsed since the calibration switch 13b was turned on. 13 (and ΔE described below) 23 Wait for the situation to subside.

[0078] Next, the control unit 11 acts as a peeling detection unit, and this potential difference ΔE13 Based on this, the control unit 11 determines whether the sodium ion selective film 41i forming the sodium ion sensitive electrode 41 has peeled off from the base portion 43a, that is, whether or not there is Na film peeling (step S104 in Figure 4). Specifically, as shown in Figure 6(B), the control unit 11 determines the potential difference ΔE 5 seconds after contact with the standard solution. 13 If the potential difference ΔEth (=0.01[V]) is below the threshold ΔEth, it is determined that the sodium ion selective membrane 41i has peeled off from the base portion 43a (Na membrane peeling has occurred) (YES in step S104 in Figure 4). In this case, the process proceeds to step S108, which will be described later. Meanwhile, the control unit 11 determines the potential difference ΔE 5 seconds after contact with the standard solution, as shown in Figure 5(B). 13 If the threshold ΔEth (=0.01[V]) is greater than or equal to the threshold, it is determined that the sodium ion selective membrane 41i has not peeled off from the base portion 43a (no Na film peeling) (NO in step S104 of Figure 4).

[0079] Next, the control unit 11 acts as a switching control unit and controls the changeover switch 80 shown in Figure 3 with the switching control signal Ctrl to switch the switching unit 80a from the active position to the normal position, and also switches the switching unit 80b from the normal position to the active position. This turns on the conductive path 81 instead of the conductive path 82 (step S105 in Figure 4) and turns on the conductive path 84 instead of the conductive path 83 (step S106 in Figure 4), creating a second connection state. In this second connection state, the contact electrode 21b of the connector 21 is electrically connected to the input unit 14a of the peel detection unit 14 via the wiring 71b, conductive path 84, and wiring 71w. The contact electrode 21c of the connector 21 is electrically connected to the input unit 14b of the peel detection unit 14 via the wiring 71c (i.e., wiring 71x). Therefore, the peel detection unit 14 receives the second potential E2 generated by the potassium ion-sensitive electrode 42 at the input unit 14a, and the third potential E3 generated by the auxiliary electrode 46 at the input unit 14b, and the potential difference ΔE between the second potential E2 and the third potential E3 23 The signal is amplified and input to the control unit 11.

[0080] Next, the control unit 11 acts as a peeling detection unit, and this potential difference ΔE 23 Based on this, the control unit 11 determines whether the potassium ion selective film 42i forming the potassium ion sensitive electrode 42 has peeled off from the base portion 44a, that is, whether or not there is K film peeling (step S107 in Figure 4). Specifically, as shown in Figure 7(B), the control unit 11 determines the potential difference ΔE 5 seconds after contact with the standard solution. 23 If the potential difference ΔEth (=0.01[V]) is below the threshold ΔEth, it is determined that the potassium ion selective membrane 42i has peeled off from the base portion 44a (K membrane peeling has occurred) (YES in step S107 in Figure 4). In this case, the process proceeds to step S108, which will be described later. Meanwhile, the control unit 11 determines the potential difference ΔE 5 seconds after contact with the standard solution, as shown in Figure 5(B). 13 If the value is greater than or equal to the threshold ΔEth (=0.01[V]), it is determined that the potassium ion selective membrane 42i has not peeled off from the base portion 44a (no K membrane peeling) (NO in step S107 in Figure 4). In this case, proceed to step S110, which will be described later.

[0081] If it is determined that the Na film has peeled off (YES in step S104 in Figure 4), or if it is determined that the K film has peeled off (YES in step S107 in Figure 4), the process proceeds to step S108 as described above. In step S108, the control unit 11 acts as a notification unit and notifies of an abnormality (error) indicating that the ion-selective film has peeled off. In this example, the control unit 11 displays "ERROR" on the display unit 20 as a string indicating that the ion-selective film has peeled off. Depending on whether the sodium ion-selective film 41i or the potassium ion-selective film 42i has peeled off, for example, "Na_ERROR" or "K_ERROR" may be displayed. If both the sodium ion-selective film 41i and the potassium ion-selective film 42i have peeled off, for example, "Na,K_ERROR" may be displayed to indicate that both films have peeled off.

[0082] The user can see the above-mentioned display indicating an abnormality (error) and understand that normal measurement is impossible because the ion-selective film has peeled off. If no operation is performed by the user while this abnormality display is shown and a predetermined time (3 minutes in this example) has elapsed (YES in step S109), the control unit 11 automatically turns off the power to the electrochemical sensor 90 (step S121).

[0083] If it is determined that there is no Na film peeling (NO in step S104 in Figure 4) and that there is no K film peeling (NO in step S107 in Figure 4), this determination is used as a trigger to proceed to step S110 as described above. In step S110, the control unit 11 acts as a switching control unit and controls the changeover switch 80 shown in Figure 3 with the switching control signal Ctrl to switch the switching unit 80b from the active position to the normal position while keeping the switching unit 80a in the normal position. This keeps the conduction path 81 on and turns on the conduction path 83 instead of the conduction path 84, creating a third connection state. In this third connection state, the contact electrode 21a of the connector 21 is electrically connected to the input unit 12a of the potential difference measurement unit 12 via the wiring 71a, conduction path 81, and wiring 71u. In addition, the contact electrode 21b of the connector 21 is electrically connected to the input section 12b of the potentiometer 12 via the wiring 71b, the conductive path 83, and the wiring 71v. Therefore, as shown in step S111 of Figure 4, the potentiometer 12 receives the first potential E1 generated by the sodium ion sensitive electrode 41 with respect to the standard solution at the input section 12a, and the second potential E2 generated by the potassium ion sensitive electrode 42 at the input section 12b, and amplifies the potential difference ΔE between the first potential E1 and the second potential E2.

[0084] As a result, the control unit 11 acts as a calibration processing unit and starts the actual calibration process. Specifically, the control unit 11 waits for the value of the potential difference ΔE for the standard solution to converge (step S112 in Figure 4). Here, as shown in the "Calibration in Progress" period in Figure 8, the potential difference ΔE converges to a value corresponding to the concentration ratio Mr between sodium ions and potassium ions in the standard solution (in this example, Er) (for example, a fluctuation of less than 2 mV in 5 seconds). In this example, it is assumed that the potential difference ΔE converged to Er at time t1 shown in Figure 8. When the potential difference ΔE converges to Er (YES in step S112 in Figure 4), the control unit 11 determines the potential difference ΔE for the standard solution as Er, and uses this potential difference Er and the concentration ratio Mr to determine the sensitivity S1 based on the previously described equation (Eq. 1) (calibration complete). Then, it notifies the user that the calibration is complete. In this example, the control unit 11 causes the display unit 20 to display "CAL_OK" as a string indicating that calibration is complete (step S113 in Figure 4).

[0085] Upon seeing the indication that the calibration is complete, the user performs the operation of replacing the electrolyte solution in contact with region A1 from the standard solution to the urine solution to be measured. Here, the operation of replacing the electrolyte solution in contact with region A1 from the standard solution to the urine can be performed, for example, by sprinkling urine on one end 31e of the test piece 30, or by immersing one end 31e of the test piece 30 in urine collected in a container (not shown).

[0086] At this time, the sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 come into contact with the urine and generate a first potential E1 corresponding to the concentration of sodium ions and a second potential E2 corresponding to the concentration of potassium ions, respectively.

[0087] Next, the user presses the measurement switch 13c to instruct the start of measurement of the concentration ratio Ms (=C1 / C2) between sodium ions and potassium ions in the urine (step S114 in Figure 4). The control unit 11 then starts the urine measurement process. That is, the control unit 11 acts as a second calculation unit and observes the potential difference ΔE (=E1-E2) between the sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 of the test piece 30 via the potential difference measurement unit 12 (step S115). Here, as shown in the "waiting for urine measurement" period in Figure 8, the potential difference ΔE fluctuates temporarily (around time t2 in this example) due to the substitution of the electrolyte. However, after the initial fluctuation, the potential difference ΔE gradually converges again to a value corresponding to the concentration ratio between sodium ions and potassium ions in the urine (Es in this example), as shown in the "during urine measurement" period in Figure 8 (for example, a fluctuation of less than 2mV in 5 seconds). In this example, we assume that the potential difference ΔE converges to Es at time t3 shown in Figure 8. When the control unit 11 determines that the potential difference ΔE for the urine is Es (step S117 in Figure 4), it confirms that the potential difference ΔE converges to Es (YES in step S116 in Figure 4).

[0088] Next, the control unit 11 acts as a second calculation unit and uses the sensitivity S1 obtained in step S113 of Figure 4 and the potential difference Es to calculate the concentration ratio Ms (=C1 / C2) (i.e., Na / K ratio) for the urine based on the previously described equation (Eq. 1) (step S118 of Figure 4).

[0089] Next, the control unit 11 displays the measurement result (in this example, the Na / K ratio) on the display unit 20 (step S119 in Figure 4). For example, suppose the measured Na / K ratio is 4.0. In that case, the display unit 20 displays "Na / K=4.0" as a string representing the measurement result. At the same time, in this example, the control unit 11 operates the communication unit 19 to transmit information representing the measured value data (i.e., the Na / K ratio) to another device (in this example, a server) via the network 900.

[0090] After this, the control unit 11 waits for any instruction to be input by the user via the operation unit 13 (step S120 in Figure 4). If a predetermined time (3 minutes in this example) has elapsed without any instruction being input (YES in step S120), the control unit 11 automatically turns off the power to the electrochemical sensor 90 (step S121).

[0091] Thus, in this electrochemical sensor 90 electrolyte analysis method flow, measurement is performed only after confirming that there is no Na film peeling (NO in step S104 of Figure 4) and no K film peeling (NO in step S107 of Figure 4). Therefore, the reliability of the measurement result (Na / K ratio in this example) can be increased.

[0092] Furthermore, since this electrochemical sensor 90 includes a test piece 30 and a main body 10 to which the test piece 30 is detachably attached, it is possible to use a test piece 30 in a manner in which it is discarded after use and a new test piece is attached to the main body 10.

[0093] The example above described measuring the concentration ratio between sodium ions and potassium ions as the first and second ion species, but it is not limited to that. This electrochemical sensor 90 can be applied to measuring the concentration ratio between various ions other than sodium ions and potassium ions, such as calcium ions, chloride ions, lithium ions, nitrate ions, nitrite ions, sulfate ions, sulfite ions, iodide ions, magnesium ions, bromide ions, perchlorate ions, and hydrogen ions.

[0094] (Variation 1) Furthermore, in the above example, the test piece 30 is provided with two ion-sensitive electrodes, a sodium ion-sensitive electrode 41 and a potassium ion-sensitive electrode 42. However, it is not limited to this, and it may be provided with only one ion-sensitive electrode. Specifically, for example, in Figures 2(A) and 2(B), the test piece may be provided with only the first main electrode layer 43 of the first and second main electrode layers 43 and 44, and with only the sodium ion-selective membrane 41i provided on the base portion 43a of the first main electrode layer 43 of the two ion-selective membranes 41i and 42i. In that case, during operation, the control unit 11 acts as a peeling determination unit and determines the potential difference ΔE between the first potential E1 generated by the sodium ion-sensitive electrode 41 and the third potential E3 generated by the auxiliary electrode 46. 13 Based on this, it is determined whether or not there is Na film peeling. Furthermore, triggered by the determination that there is no Na film peeling, the control unit 11 acts as a first calculation unit and calculates the potential difference ΔE 13 Based on this, the concentration of sodium ions contained in the electrolyte is calculated. In this way, if the measurement is performed after confirming that there is no peeling of the Na film, the reliability of the measurement result (in this case, sodium ion concentration) can be increased.

[0095] Conversely, the device may also be equipped with only the second main electrode layer 44 of the first and second main electrode layers 43 and 44, and only the potassium ion selective membrane 42i provided on the base portion 44a of the second main electrode layer 44 of the two ion selective membranes 41i and 42i. In that case, during operation, the control unit 11 acts as a peeling determination unit and determines the potential difference ΔE between the second potential E2 generated by the potassium ion sensitive electrode 42 and the third potential E3 generated by the auxiliary electrode 46. 23 Based on this, it is determined whether or not there is K film peeling. Furthermore, triggered by the determination that there is no K film peeling, the control unit 11 acts as a first calculation unit and calculates the potential difference ΔE 23 Based on this, the concentration of potassium ions contained in the electrolyte is calculated. In this way, if the measurement is performed after confirming that there is no K film peeling, the reliability of the measurement result (in this case, potassium ion concentration) can be increased.

[0096] As shown in this modified example 1, if the test piece 30 is equipped with only one ion-sensitive electrode, it becomes possible to reduce the X-direction and Y-direction dimensions of the test piece 30 (substrate 31). Furthermore, the configuration of the main body 10 can be simplified.

[0097] (Modification 2) Furthermore, in the above example, the auxiliary electrode 46 (auxiliary region 51w3) of the test piece 30 is positioned in Figures 2(A) and 2(B) at a location corresponding to the space between one end 31e and the potassium ion-sensitive electrode 42 (second specific region 51w2) with respect to the X direction. However, it is not limited to this, and may be positioned on the side of one end 31e with respect to the X direction, for example, closer to the other end 31f than the sodium ion-sensitive electrode 41 (first specific region 51w1). In this case, the sodium ion-sensitive electrode 41 and the potassium ion-sensitive electrode 42 are positioned closer to one end 31e with respect to the X direction than in Figures 2(A) and 2(B).

[0098] Even with this arrangement, when the electrolyte is brought into contact with one end 31e of the substrate 31 (for example, region A1 shown by the dashed line in Figure 5(A)), the electrolyte can come into integral contact with the sodium ion-sensitive electrode 41, the potassium ion-sensitive electrode 42, and the auxiliary electrode 46. Therefore, the control unit 11 acts as a peeling determination unit and determines the potential difference ΔE between the first potential E1 generated by the sodium ion-sensitive electrode 41 and the third potential E3 generated by the auxiliary electrode 46. 13 Based on this, it is possible to determine whether or not there is Na film peeling. Similarly, the control unit 11 acts as a peeling determination unit and determines the potential difference ΔE between the second potential E2 generated by the potassium ion sensitive electrode 42 and the third potential E3 generated by the auxiliary electrode 46. 23 Based on this, it is possible to determine whether or not there is K film peeling.

[0099] (Variation 3) Furthermore, in the above example, as shown in Figures 2(A) and 2(B), the sodium ion-sensitive electrode 41, potassium ion-sensitive electrode 42, and auxiliary electrode 46 are all provided on the surface 31a, which is one of the main surfaces of the substrate 31, in the test piece 30, but the invention is not limited to this. For example, in the test piece 30, the sodium ion-sensitive electrode 41 and potassium ion-sensitive electrode 42 may be provided on the surface 31a of the substrate 31, while the auxiliary electrode 46 may be provided on the back surface 31b, which is the other main surface of the substrate 31. In this case, the base portion 43a and electrode pad portion 43c associated with the sodium ion-sensitive electrode 41, and the base portion 44a and electrode pad portion 44c associated with the potassium ion-sensitive electrode 42, are provided on the surface 31a of the substrate 31, as in the above example. On the other hand, the auxiliary electrode layer 48, which includes the auxiliary electrode 46, lead portion 48b, and electrode pad portion 48c, is provided on the back surface 31b of the substrate 31. Furthermore, the connector 21 of the main body 10 has three contact electrodes that, when the other end 31f of the substrate 31 is inserted, correspond to the electrode pad portion 43c and electrode pad portion 44c on the surface 31a of the substrate 31, and the electrode pad portion 48c on the back surface 31b of the substrate 31, respectively.

[0100] Thus, in the test specimen 30, when the sodium ion-sensitive electrode 41 and potassium ion-sensitive electrode 42 are provided on the surface 31a of the substrate 31, while the auxiliary electrode 46 is provided on the back surface 31b of the substrate 31, the number of elements provided on the surface 31a of the substrate 31 is reduced, making it possible to reduce the Y-direction dimension of the test specimen 30.

[0101] (Modification 4) Furthermore, in the example above, as shown in Figure 2(A), the shape of the auxiliary electrode 46 (auxiliary region 51w3) of the test piece 30 was assumed to be circular, but it is not limited to this. The shape of the auxiliary electrode 46 (auxiliary region 51w3) may be, for example, rectangular.

[0102] The embodiments described above are illustrative, and various modifications are possible without departing from the scope of this invention. Each of the above embodiments can stand on its own, but they can also be combined. Furthermore, various features within different embodiments can stand on their own, but they can also be combined. [Explanation of symbols]

[0103] 10 Main Unit 10s cabinet 21 Connectors 22 slots 30 Test pieces for electrolyte analysis 41. Sodium ion-sensitive electrode 41i Sodium ion selective membrane 42 Potassium ion-sensitive electrodes 42i Potassium ion selective membrane 46 Auxiliary electrode 90 Electrochemical Sensors

Claims

1. An electrolyte analyzer for measuring the concentration of ions contained in an electrolyte, a substrate extending in one direction from one end to the other end; a main electrode layer including a main base portion provided in a specific region on one of the pair of main surfaces of the substrate on the one end side in the one direction, and a main extension portion extending from the main base portion to the other end side; an ion selective membrane that is provided in contact with the main base portion so as to cover the main base portion in the specific region and that has a property of selectively transmitting the ions; an auxiliary electrode layer including an auxiliary base portion provided in an auxiliary region different from the specific region on the one or other of the pair of main surfaces of the substrate on the one end side in the one direction, and an auxiliary extension portion extending from the auxiliary base portion to the other end side; the auxiliary electrode layer is disposed at a distance from the main electrode layer, a peeling determination unit that, in a state in which an electrolyte is in contact with the one end of the substrate so as to cover the one end, acquires a potential of the main base portion via the main extension portion and acquires a potential of the auxiliary base portion via the auxiliary extension portion, and determines whether the ion selective membrane has peeled from the main base portion based on a potential difference between the acquired potentials of the main base portion and the auxiliary base portion. An electrolyte solution analyzer comprising:

2. 2. The electrolytic solution analyzer according to claim 1, The conductive material forming the main base portion is the same as the conductive material forming the auxiliary base portion. An electrolyte solution analyzer characterized by:

3. 3. The electrolytic solution analyzer according to claim 1, The peeling determination unit determines whether the ion selective membrane is peeled from the main base based on whether the potential difference is below a predetermined threshold. An electrolyte solution analyzer characterized by:

4. 4. The electrolytic solution analyzer according to claim 1, and a notifying unit that notifies the occurrence of an abnormality that the ion selective membrane has peeled off when it is determined that the ion selective membrane has peeled off from the main base portion. An electrolyte solution analyzer characterized by:

5. 5. The electrolytic solution analyzer according to claim 1, and a first calculation unit that, when it is determined that the ion selective membrane is not peeled off from the main base portion, uses the determination as a trigger to calculate the concentration of the ions contained in the electrolyte based on the potential difference between the main base portion and the auxiliary base portion. An electrolyte solution analyzer characterized by:

6. 6. The electrolytic solution analyzer according to claim 1, the electrolyte solution contains a first ion species and a second ion species that are different from each other; the specific region includes first and second specific regions set apart from each other on the one main surface on a side of the one end in the one direction, The main electrode layer has, on the one main surface of the substrate, a first main base portion provided in the first specific region, and a first main extension portion extending from the first main base portion toward the other end; a second main base portion provided in the second specific region, and a second main extension portion extending from the second main base portion toward the other end, the first main base portion and the first main extension portion are spaced apart from the second main base portion and the second main extension portion; The ion selective membrane is a first ion selective membrane that is provided in contact with the first main base portion so as to cover the first main base portion in the first specific region, and that has a property of selectively transmitting the first ion species; a second ion selective membrane provided in contact with the second main base portion so as to cover the second main base portion in the second specific region, the second ion selective membrane having a property of selectively transmitting the second ion species; The peeling determination unit includes: With an electrolytic solution in contact with the one end of the substrate so as to cover it, a first potential indicated by the first main base portion and a second potential indicated by the second main base portion are obtained via the first and second main extension portions, respectively, and a third potential indicated by the auxiliary base portion is obtained via the auxiliary extension portion; Whether the first ion selective membrane has peeled off from the first main base portion is determined based on the potential difference between the acquired first potential and the acquired third potential, and whether the second ion selective membrane has peeled off from the second main base portion is determined based on the potential difference between the acquired second potential and the acquired third potential. An electrolyte solution analyzer characterized by:

7. 7. The electrolytic solution analyzer according to claim 6, a second calculation unit that, when it is determined that the first ion selective membrane is not peeled off from the first main base portion and the second ion selective membrane is not peeled off from the second main base portion, calculates a concentration ratio between the first ion species and the second ion species contained in the electrolyte based on a potential difference between the first potential and the second potential, using the determination as a trigger. An electrolyte solution analyzer characterized by:

8. The electrolytic solution analyzer according to claim 7, a test strip comprising the substrate, the main electrode layer, the ion selective membrane, and the auxiliary electrode layer; a main body to which the test piece is detachably attached, The above body is a connector having first, second and third contact electrodes that come into contact with the first main extension portion, the second main extension portion and the auxiliary extension portion, respectively, when the other end of the test piece is inserted; The peeling determination unit and the second calculation unit are mounted An electrolyte solution analyzer characterized by:

9. The electrolytic solution analyzer according to claim 8, The above body is a wiring group for connecting the first, second, and third contact electrodes of the connector to the peeling determination unit and the second calculation unit; a changeover switch inserted in the wiring group; a switching control unit; The switching control unit controls the changeover switch, For the peeling determination unit, a first connection state is created in which the first contact electrode and the third contact electrode of the connector are electrically connected to the peeling determination unit via the wiring group, and a second connection state is created in which the second contact electrode and the third contact electrode are electrically connected to the peeling determination unit via the wiring group, and For the second calculation unit, a third connection state is created in which the first contact electrode and the second contact electrode of the connector are connected to the second calculation unit via the wiring group. An electrolyte solution analyzer characterized by:

10. 10. The electrolytic solution analyzer according to claim 1, The auxiliary electrode layer is provided on one of the pair of principal surfaces. An electrolyte solution analyzer characterized by:

11. 1. A method for analyzing an electrolyte solution for measuring a concentration of ions contained in the electrolyte solution, comprising: a substrate extending in one direction from one end to the other end; a main electrode layer including a main base portion provided in a specific region on one of the pair of main surfaces of the substrate on the one end side in the one direction, and a main extension portion extending from the main base portion to the other end side; an ion selective membrane that is provided in contact with the main base portion so as to cover the main base portion in the specific region and that has a property of selectively transmitting the ions; an auxiliary electrode layer including an auxiliary base portion provided in an auxiliary region different from the specific region on the one or other of the pair of main surfaces of the substrate on the one end side in the one direction, and an auxiliary extension portion extending from the auxiliary base portion to the other end side; the auxiliary electrode layer is disposed at a distance from the main electrode layer, The electrolyte analysis method includes: a potential of the main base portion is obtained through the main extension portion, and a potential of the auxiliary base portion is obtained through the auxiliary extension portion, in a state where an electrolytic solution is in contact with the substrate so as to cover the one end side; Whether or not the ion selective membrane has peeled off from the main base portion is determined based on the obtained potential difference between the main base portion and the sub-base portion.

1. A method for analyzing an electrolyte solution.

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