Analysis device, electrolyte concentration measurement method, and analysis apparatus

Abstract

To provide an analysis device capable of reducing a risk of contaminating a hand, an arm and a measuring place by a specimen running along a cover surface of the analysis device after measurement, since the specimen remains on a surface of the analysis device even after the measurement, in electrolyte concentration measurement using the analysis device for measuring an electrolyte concentration by performing potential difference measurement.SOLUTION: Wherein a channel wall is formed of a hydrophobic material inside a porous substrate, the porous substrate is divided by the channel wall into a channel region surrounded by the channel wall and a margin part present outside the channel wall, and a hydrophobic cover is provided on both surfaces of the porous substrate, the cover is provided with an opening for introducing a specimen, an area of the margin part viewed from the opening side is 50% or more of an area of the flow path area viewed from the opening side, and the margin part has a region not covered with the cover.SELECTED DRAWING: FIG. 1 (a)

Description

[Technical Field]

[0001] The present invention relates to an analytical device having a flow path region surrounded by a flow path wall provided inside a porous substrate, a method for measuring electrolyte concentration using the analytical device, and an analytical apparatus. [Background technology]

[0002] In recent years, microanalysis chips, which utilize micro-sized fine channels to efficiently perform biochemical analysis within a single chip, have been attracting attention in a wide range of fields, including biochemical research, medicine, drug discovery, healthcare, the environment, and food.

[0003] In the early 1990s, photolithography and molds were used to form micron-sized fine channels on glass or silicon, and microanalysis chips were developed that could perform sample pretreatment, stirring, mixing, reaction, and detection on a single chip. As a result, miniaturization of testing systems, rapid analysis, and reduction of specimens and waste liquids were realized.

[0004] Electrochemical analysis, which measures the potential between electrodes immersed in the sample to be analyzed, is widely used in the fields of medicine and the environment. Traditionally, electrochemical analysis has required sophisticated equipment and has been performed by technicians, which has limited the fields and resources in which it can be performed. Therefore, there is a need for inexpensive, easy-to-use, disposable microanalysis chips for electrochemical analysis that can be used in developing countries and remote areas that lack medical facilities, for medical activities at disaster sites, and in places such as airports where the spread of infectious diseases must be stopped at the border.

[0005] Electrochemical analysis, such as quantifying electrolyte ions in a solution, requires a stable reference electrode that can maintain a constant potential. Conventional glass reference electrodes are expensive and cannot be miniaturized because they require an internal liquid. Furthermore, they require storage in a concentrated ion solution, making them difficult to handle.

[0006] Patent Document 1 proposes a system including a microanalysis chip capable of measuring potential differences using a porous substrate, enabling electrochemical measurements that are low-cost, easy to handle, and highly disposable. This microanalysis chip includes one or more working electrodes and one reference electrode on a porous substrate. In such a microanalysis chip, electrical continuity between the two electrodes must be established by a fluid during measurement. Patent Document 1 describes the introduction of a highly concentrated aqueous solution of KCl as a reference solution into a reference region containing the reference electrode in order to obtain a stable potential at the reference electrode during measurement.

[0007] Furthermore, Non-Patent Document 1 proposes a filter paper-based analytical chip for measuring sodium and potassium ion concentrations. This analytical chip has an inlet for introducing a sample, which penetrates from the inlet into the working electrode and reference electrode regions, establishing electrical continuity between the two electrodes and measuring the potential difference. To stabilize the potential at the reference electrode, this analytical chip proposes an analytical chip with KCl ion crystals deposited on the reference electrode. During measurement, KCl dissolves in the sample, maintaining a high concentration of Cl ions in the reference electrode region, thereby achieving a stable reference electrode potential. Furthermore, an ion-selective membrane formed to cover the working electrode selects only the ions to be measured, allowing measurement to be performed without being affected by other ions.

[0008] There is also a technique for introducing a sample onto a working electrode, as described in Patent Document 2. Patent Document 2 discloses a technique for obtaining high-precision measurement of the sample concentration of specific ions contained in the sample. The flow path area other than the working electrode is covered with a laminate, leaving only the working electrode exposed, and the sample is introduced precisely. Furthermore, a technique for curving the working electrode to maintain sufficient contact between the sample and the working electrode is also disclosed. In Patent Document 2, the sample must be maintained in droplet form on the working electrode, which allows for maintaining contact between the sample and the working electrode. The working electrode surface must have a certain degree of hydrophobicity, and this technique can be realized by maintaining a droplet shape on the working electrode. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 2016 / 0033438 [Patent Document 2] Japanese Patent Publication No. 2023-048923 [Non-patent literature]

[0010] [Non-Patent Document 1] Nipapan Ruecha, Orawon Chailapakul, Koji Suzuki and Daniel Citterio “Fully Inkjet-Printed Paper-Based Potentiometric Ion-Sensing Devices” Analytical chemistry August 29, 2017 Published, 89, pp.10608-10616 Summary of the Invention [Problem to be solved by the invention]

[0011] However, when considering analytical devices configured as described in the aforementioned Patent Document 2, the following problems exist. In such a configuration in which measurement is completed while droplets remain on the analytical device, care must be taken to prevent droplets from scattering on the analytical device when disposing of the used analytical device. For example, if the analytical device is transported and disposed of manually or using a belt, there is a risk that the sample will drip down the hydrophobic cover (laminate) surface of the analytical device and onto the hands, belt, or measurement site. Similarly, at the disposal site, the sample may drip down the analytical device, causing a liquid pool and contaminating the disposal site.

[0012] In view of the above-mentioned problems, the present invention aims to provide an analytical device that can be safely disposed of by providing a marginal area in advance within the analytical device for absorbing droplets, and providing an area (analyte absorption area) that is not covered by a cover in the marginal area, thereby facilitating efficient absorption into the marginal area via the absorption area. [Means for solving the problem]

[0013] In order to achieve the above object, according to the present invention, there is provided an analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; an area of ​​the marginal portion as viewed from the opening side is 50% or more of an area of ​​the flow path region as viewed from the opening side; The marginal portion has an area that is not covered by the cover, thereby providing an analytical device.

[0014] According to the present invention, there is also provided an analytical device having a porous substrate formed of a porous material, comprising: A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The area of ​​the marginal portion as viewed from the opening side is A mm 2 The thickness of the marginal portion is T mm, the porosity of the marginal portion is P, and the amount of the sample introduced is S mm 3 Then, A×T×P≧S×0.33 The following relation is satisfied: The marginal portion has an area that is not covered by the cover.

[0015] According to the present invention, there is also provided an analytical device having a porous substrate formed of a porous material, comprising: A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The maximum volume of the droplet of the sample remaining on the exposed surface of the working electrode at the opening is defined as V max mm 3 , the area of ​​the marginal portion as viewed from the opening side is A mm 2 , where the thickness of the marginal portion is T mm and the porosity of the marginal portion is P, V max ≦A×T×P The following relation is satisfied: The marginal portion has an area that is not covered by the cover.

[0016] The present invention also provides an electrolyte concentration measurement method and an analysis apparatus that use the analytical device of the present invention. [Effects of the Invention]

[0017] By providing a marginal area in the analytical device that absorbs the sample and by providing an area in the marginal area that is not covered by a cover to promote absorption of the sample, the sample can be absorbed at the time of disposal, reducing the scattering and contamination of the sample on the device and handler. [Brief explanation of the drawings]

[0018] [Figure 1(a)] FIG. 2 is a top view of the analytical device in Example 1 before lamination. [Figure 1(b)] FIG. 2 is a top view of the analytical device in Example 1 after lamination. [Figure 1(c)] FIG. 2 is a cross-sectional view of the analytical device in Example 1 after lamination. [Figure 1(d)] FIG. 2 is a perspective view of the analytical device in Example 1 after lamination. [Figure 2] FIG. 1 is a top view of an analytical device according to the prior art before lamination. [Figure 3] 10 is a cross-sectional view showing a method for exposing a margin on the side surface of the analytical device in Example 1. FIG. [Figure 4] FIG. 1 is a perspective view showing a state in which the analytical device in Example 1 is connected to a measurement unit that measures electromotive force. [Figure 5] 1 is a perspective view showing a step of introducing a droplet of a specimen in a method for measuring an electrolyte concentration using the analytical device in Example 1. FIG. [Figure 6] FIG. 2 is a schematic diagram showing the state of the analytical device in Example 1 when it is discarded. [Figure 7] FIG. 2 is a perspective view showing a droplet of a specimen. [Figure 8] FIG. 10 is a perspective view showing a state in which a sample has been introduced into an analytical device in Example 3, in which the exposed surface of the working electrode is circular. [Figure 9(a)] FIG. 9 is a top view of the analysis device shown in FIG. 8. [Figure 9(b)] 9 is a top view showing a state in which a sample has been introduced into the analytical device shown in FIG. 8. FIG. [Figure 10] FIG. 10 is a perspective view showing a state in which a sample has been introduced into an analytical device in Example 3, in which the exposed surface of the working electrode is square. [Figure 11(a)] FIG. 11 is a top view of the analytical device shown in FIG. [Figure 11(b)] 11 is a top view showing a state in which a sample has been introduced into the analytical device shown in FIG. 10. FIG. [Figure 12(a)] FIG. 10 is a top view of the analytical device in Example 4 before lamination. [Figure 12(b)] FIG. 10 is a top view of the analytical device in Example 4 after lamination. [Figure 12(c)] FIG. 10 is a cross-sectional view of the analytical device in Example 4 after lamination. [Figure 12(d)] FIG. 10 is a perspective view of the analytical device in Example 4 after lamination. [Figure 13(a)] FIG. 10 is a top view of another analytical device in Example 4 before lamination. [Figure 13(b)] FIG. 10 is a top view of another analytical device in Example 4 after lamination. [Figure 13(c)] FIG. 10 is a cross-sectional view of another analytical device in Example 4 after lamination. [Figure 13(d)] FIG. 10 is a perspective view of another analytical device according to Example 4 after lamination. [Figure 14] FIG. 10 is a perspective view showing the state of the analytical device in Example 4 when absorbing a sample. [Figure 15] FIG. 10 is a perspective view showing a state of another analytical device in Example 4 during sample absorption. [Figure 16(a)] FIG. 10 is a top view of the analytical device in Example 5 before lamination. [Figure 16(b)] FIG. 10 is a top view of the analytical device in Example 5 after lamination. [Figure 16(c)] FIG. 10 is a cross-sectional view of the analytical device in Example 5 after lamination. [Figure 16(d)] FIG. 10 is a perspective view of the analytical device in Example 5 after lamination. [Figure 17] FIG. 10 is a perspective view showing the state of the analytical device in Example 5 when it is discarded. [Figure 18] FIG. 10 is a schematic diagram of an analytical device in Example 6. [Figure 19] FIG. 13 is a perspective view showing a state in which the analytical device in Example 6 is connected to a measurement unit that measures electromotive force. [Figure 20] FIG. 13 is a perspective view showing the step of introducing a specimen in the method for measuring the concentration of an electrolyte using the analytical device in Example 6. [Figure 21] FIG. 10(a) is a perspective view showing a part of the analysis apparatus in a state where the belt is tilted in Example 6, and FIG. 10(b) is a perspective view showing the analysis device in the state shown in FIG. [Figure 22] FIG. 13 is a perspective view showing the state of the analytical device in Example 7 when discarded. DETAILED DESCRIPTION OF THE INVENTION

[0019] The analytical device, electrolyte concentration measurement method, and analytical apparatus according to the present invention for solving the above-mentioned problems will be described based on the following examples. Note that the examples and accompanying drawings shown below are merely examples and are not intended to limit the technical scope of the present invention.

[0020] [Example 1] An analytical device according to one embodiment of the present invention is an analytical device having a porous substrate formed of a porous material, wherein a flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a marginal portion located outside the flow path wall, the flow path region having a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow path chamber having a reference electrode, the second flow path chamber having a working electrode, the working electrode containing a hydrophobic material, and hydrophobic covers provided on both sides of the porous substrate, the covers having an opening communicating with the second flow path chamber for introducing a sample, the covers being provided so as to cover at least the flow path region except for the opening, the area of ​​the marginal portion as viewed from the opening side being 50% or more of the area of ​​the flow path region as viewed from the opening side, and the marginal portion having an area not covered by the cover. The analytical device according to the present invention may have a porous substrate having a flat plate shape.

[0021] <Flow path area configuration> The analytical device 100 in Example 1 will be described with reference to Figures 1(a) to 1(d). Figures 1(a) and 1(b) are simplified top views of the analytical device 100. Figure 1(a) is a view before lamination with a hydrophobic cover, and Figure 1(b) is a view after lamination. Figure 1(c) is a simplified cross-section of the analytical device 100 shown in Figure 1(b) taken along line A-A'.

[0022] The analytical device 100 has a flow path region surrounded by a flow path wall 4 provided inside a porous substrate S1. The flow path region is composed of a first flow path chamber 1, a second flow path chamber 2, and a connecting flow path 3. The connecting flow path 3 connects the first flow path chamber 1 and the second flow path chamber 2.

[0023] A reference electrode 5 is disposed in the first flow chamber 1. The reference electrode 5 has a reaction region in the first flow chamber 1 that serves as a contact point with the sample during measurement and measures the electrolyte concentration of the sample. The reference electrode 5 also has a lead wire 8a that is connected to the reaction region and extends continuously onto the flow wall 4. The top and side surfaces of the reaction region of the reference electrode 5 are covered with ion crystals 7 such as potassium chloride.

[0024] A working electrode 6 is disposed in the second flow chamber 2. The working electrode 6 also has a reaction region for measuring the electrolyte concentration of the specimen within the second flow chamber 2 as a contact point with the specimen during measurement, and has a lead wire 8b connected to the reaction region and continuously extending onto the flow channel wall 4. The specimen is introduced into this second flow chamber 2.

[0025] In FIGS. 1(a) and 1(b), the portion covered with the ion crystal 7 and the portion covered with the cover 9 are indicated by dotted lines.

[0026] In Example 1, a hydrophobic resin was placed on a paper porous substrate S1 having a thickness T (shown in FIG. 1(c)) of 0.1 mm and a porosity of 0.5, and then thermally fixed to form a channel wall 4 that was impermeable to samples, thereby forming a channel pattern.

[0027] In this example, a paper substrate was used as the porous substrate S1, but the porous substrate is not limited to paper. The porous substrate may be any substrate that generates capillary action in a liquid, and may have pores with a mesh structure such as open cells or nanofibers inside, or may be made of resin, glass, an inorganic substrate, fabric, metal paper, or the like.

[0028] In this example, a porous substrate S1 with a thickness of 100 μm was used, but the thickness of the porous substrate in the analytical device according to the present invention is not limited to this and can be selected appropriately depending on the purpose. Porous substrates with a thickness of approximately 20 μm to 300 μm are often used. If the thickness of the porous substrate is 20 μm or less, it may not be able to maintain its strength as a substrate. Furthermore, if the thickness of the porous substrate is 300 μm or more, materials such as coating films may easily diffuse within the analytical device, which may result in a deterioration in dimensional accuracy. However, depending on the application, a thick porous substrate with a thickness of approximately 600 μm may be used by adjusting the arrangement within the analytical device.

[0029] In the analytical device according to the present invention, the porosity of the porous substrate can be appropriately selected depending on the purpose, but is preferably 0.2 to 0.9. A porosity of 0.9 or less makes it easier to maintain the strength of the substrate, and a porosity of 0.2 or more improves the permeability of the sample liquid (analyte), which is preferable. The porosity is Porosity = (true density - apparent density) / true density It is calculated as follows. Also, the apparent density (g / cm 3 )teeth, Apparent density (g / cm 3 ) = basis weight (g / m 2 ) / Thickness (mm) x 1000 It is calculated from

[0030] The hydrophobic resin that forms the flow path wall is not particularly limited, and examples thereof include polyester resin, vinyl resin, acrylic resin, styrene-acrylic resin, polyethylene, polypropylene, polyolefin, ethylene-vinyl acetate copolymer resin, and ethylene-acrylic acid copolymer resin.

[0031] In this example, the flow path pattern was formed by thermal fixing after disposing the hydrophobic resin. In this case, a method can be used in which toner particles are used as the hydrophobic resin (thermoplastic resin) and thermal fixing is performed using an electrophotographic device. For this method, reference can be made to JP 2021-37612 A. The method for forming the flow path pattern is not limited to this. It is sufficient to form a flow path pattern having the desired flow path region, and in addition to a cutting method in which a paper porous substrate is cut to leave only the flow path shape, the flow path walls may be formed using an inkjet printer or wax printer.

[0032] As shown in FIG. 1(b), in addition to the configuration shown in FIG. 1(a), the analytical device 100 includes a hydrophobic cover 9, such as a laminate film that is impermeable to samples, to reduce contamination and evaporation during sample introduction. In the analytical device 100 of this example, both sides of the device are covered except for the second flow channel chamber 2 and portions of the lead wires 8a and 8b. The cover 9 is a laminate film made of a PET film and an acrylic adhesive. The cover 9 on one side of the porous substrate S1, on both sides of which the cover 9 is provided, has an opening 9a that communicates with the second flow channel chamber 2 and is used to introduce the sample. To connect the lead wires 8a and 8b to a measurement unit for measurement, which will be described later, the cover is designed to avoid covering the portions of the lead wires 8a and 8b, although the connection between the measurement unit and the electrodes may be different.

[0033] <Electrode formulation> The electrode formulation in Example 1 will be described. A reference electrode 5 using Ag / AgCl was provided in the first flow path chamber 1. Furthermore, 3.5 mg of ion crystals 7, which were KCl ion crystals, were placed on the reference electrode 5. The material of the ion crystals 7 is not limited to KCl ion crystals as long as it contains Cl ions, and ions such as NaCl may also be used. The mass of the ion crystals 7 to be placed is the amount that will result in a saturated solution when the KCl ion crystals are dissolved in pure water with a volume equivalent to the volume of the first flow path chamber 1.

[0034] On the other hand, Ag / AgCl was used for the working electrode 6 of the second flow channel chamber 2, as was the reference electrode 5. As the working electrode 6, an electrode mainly made of carbon or an electrode made of a conductive polymer such as PEDOT:PSS (a dispersion of polyethylenedioxythiophene and polystyrene sulfonic acid) may also be used.

[0035] The surfaces of both the reference electrode 5 and the working electrode 6 are covered with AgCl alone (called AgCl coating) by combining Ag with Cl (called halogenation) using an oxidizing liquid such as FeCl3 aqueous solution.

[0036] When measuring the electrolyte concentration of a sample, an electromotive force is generated, which is generated by a shift in the following equilibrium reaction:

number

[0037] The potential of the reference electrode 5 in contact with the liquid saturated with KCl ion crystals stabilizes at a constant value, while the potential of the working electrode 6 stabilizes at a value that varies depending on the ion concentration of the sample.

[0038] The lead wires 8a and 8b were made of Ag / AgCl (molar ratio 6:4). Because Ag is conductive, it can function as a lead wire if a certain amount of Ag is mixed in. To prevent halogenation, a masking process was used to ensure conductivity.

[0039] Other ions whose concentrations are to be measured can be measured by forming an ion-selective membrane corresponding to the ion. For example, to measure the concentration of Na ions, a Na ion-selective membrane is formed to cover the working electrode 6. The Na ion-selective membrane can be formed from the following materials: 3.0% by mass of ion-selective material Bis(12-crown-4) (bis(12-crown-4)) 0.5% by mass of potassium tetrakis (4-chlorophenyl) borate as an anion scavenger o-nitrophenyl octyl ether 64.0% by mass Polyvinyl chloride 32.5% by mass By doing so, a voltage corresponding to the concentration of Na ions is output. In this example, an example of a working electrode for measuring Cl ions is shown.

[0040] <Analysis device shape> (flow area and inlet) 1(b) and 1(c), in this embodiment, the inlet for dropping the sample is an opening 9a provided in the cover 9, and the opening 9a is provided to follow the shape of the second flow channel chamber 2. In the inlet provided on the upper surface side of the analytical device 100, the area of ​​the exposed surface 6a (reaction region) of the working electrode 6 (AgCl) is 3 mm × 3 mm = 9 mm 2The AgCl coating has a thickness of 0.01 mm. As shown in FIG. 1(c), a sample 11 (shown as a dotted pattern) is introduced through the opening 9a. A droplet of the sample 11 covers the exposed surface 6a of the working electrode 6, bringing the working electrode 6 and the sample 11 into sufficient contact to generate an electromotive force. Because the AgCl coating on the exposed surface 6a of the working electrode 6 is hydrophobic, a portion of the sample 11 shown in FIG. 1(c) maintains the shape of a droplet (approximately hemispherical) on the exposed surface 6a due to tension. Meanwhile, a portion of the sample 11 seeping from the second flow channel chamber 2 into the connecting flow channel 3 permeates through the connecting flow channel 3 to the reference electrode 5 in the first flow channel chamber 1. A sufficient amount of sample is required to stably generate an electromotive force along with the permeation phenomenon; in this example, 30 μl of sample was introduced. This amount is enough to allow a droplet to remain on the exposed surface 6a of the working electrode 6 from immediately after introduction until measurement. The hydrophobicity of the working electrode 6 (exposed surface 6a) needs to be appropriate so that a droplet can be held on the exposed surface 6a and spread out. In terms of the contact angle, a value of about 50° to 100° is preferable.

[0041] (Space for absorbing the sample) As a feature of the present invention, a margin 10 for absorbing droplets of a specimen 11 is provided on the outer side of the flow path wall 4 on the analytical device 100 as shown in FIG. 1(a). The marginal area is a porous area outside the flow path wall (a portion where no flow path wall is formed), and includes both the area not covered by the cover and the area covered by the cover. The area of ​​the marginal area as viewed from the opening side (top side) includes the area of ​​the area covered by the cover 9, and in this embodiment, the area of ​​the marginal area 10 as viewed from the opening 9a side is set to 2 cm. 2 It was decided.

[0042] For comparison, FIG. 2 shows a top view of a conventional analytical device 200 before lamination. The analytical device 200 includes a porous substrate S2 on which a first flow channel chamber 21, a second flow channel chamber 22, a connecting flow channel 23, a flow channel wall 24, a reference electrode 25, a working electrode 26, ionic crystals 27, lead wires 28a and 28b, and a cover (not shown). The shape, flow channel region configuration, and electrode formulation of the analytical device 200 are similar to those of the analytical device 100 of Example 1, except that the analytical device 200 does not have a marginal portion. Like the analytical device 100, the analytical device 200 has a hydrophobic cover with an opening, but this is not shown for ease of explanation. In FIG. 2, the portion covered with the ionic crystals 27 is indicated by a dotted line.

[0043] The analytical device 200 according to the prior art shown in Fig. 2 does not have a marginal area and is unable to absorb any sample that has not been absorbed into the flow path area. Unlike the analytical device 200 shown in Fig. 2, the analytical device according to the present invention shown in Fig. 1 has a marginal area 10, which allows it to absorb any sample remaining on the analytical device 100 and enable it to be safely disposed of without contaminating the surrounding area.

[0044] -Features and effects of this embodiment- In this example, the area of ​​the flow path region is set to 4 cm 2The area of ​​the flow channel region is the area of ​​the flow channel region (first flow channel chamber, second flow channel chamber, and connecting flow channel) surrounded by the flow channel wall as viewed from the opening side (the top side where the sample is introduced). This area includes the area covered by the cover as well as the area not covered by the cover. If an electrode or the like is present inside, it also includes the area of ​​the porous portion below it. The area of ​​the flow channel region is related to the sample volume and is set to a size that allows a predetermined sample volume to fill the flow channel region. Due to variations in the area of ​​the flow channel region and variations in the sample volume, the sample volume may exceed the amount that can be filled into the flow channel region. Furthermore, when the sample is introduced onto the exposed surface of a hydrophobic working electrode and retained on the exposed surface, the sample remains on the exposed surface of the working electrode even after the measurement is completed. The sample volume is set to an amount that takes this into account, and the sample is introduced and measured. The larger the flow channel region to be filled with the sample, the larger the sample volume to be introduced, and the larger the sample volume tends to be, resulting in a larger sample volume remaining on the surface of the analytical device after the measurement. According to this example, the area of ​​the margin required to absorb the sample droplets can be estimated from the area of ​​the flow channel region.

[0045] In this embodiment, the area of ​​the margin for absorbing the sample is set to be the area of ​​the margin as seen from the opening side (the top surface side where the sample is introduced) ≧ the area of ​​the flow path region as seen from the opening side (the top surface side where the sample is introduced) × 0.50.

[0046] To be precise, the sample filling volume in the marginal area is set to be 50% or more of the sample filling volume in the flow path area, but in this embodiment, since the thickness and porosity of the porous area (flow path area and marginal area) are the same, this can be expressed by comparing the areas.

[0047] In this example, the area of ​​the flow path region is 4 cm 2 This requires a 30 μl sample, of which about 10 μl cannot be adequately retained within the flow path area, posing a risk of contaminating the surrounding area when the analytical device is discarded.

[0048] As a result of the experiment, the amount of sample that can be absorbed into the porous part per unit area was 5 μl / cm 2 Therefore, at least 2 cm 2The wider the margin, the greater the margin for sample absorption. However, there is a trade-off with increasing the size of the analytical device, so the optimum area is selected. In this case, a margin of 2 cm, which is equivalent to 50% of the area of ​​the flow channel region, is used. 2 A margin was provided.

[0049] See FIG. 1(d), which is a perspective view of the analytical device 100 according to this embodiment. In FIG. 1(d), the portion covered by the cover 9 is omitted. As shown in FIG. 1(d), the marginal portion 10 is provided with an absorbent portion 12, which is a region not covered by the cover 9. FIG. 3 is a cross-sectional view showing a method for exposing a porous portion (the region not covered by the cover 9, i.e., the absorbent portion 12) by exposing a portion of the marginal portion 10 of the analytical device 100 according to this embodiment. FIG. 3 shows the analytical device 100 in a state before the absorbent portion 12 is exposed. Most analytical device covers according to conventional techniques cover the side surfaces of the analytical device. In this embodiment, the marginal portion 10 is exposed as the absorbent portion 12 by, for example, cutting the portion of the cover 9 covering the side surface of the analytical device 100 (here, this refers to the surface approximately perpendicular to the opening 9a) along the dotted line in FIG. 3. This allows the analytical device 100 to have an area (absorbent section 12) that is not covered by the cover 9 of the margin section 10 on the side surface (surface substantially perpendicular to the opening 9a).

[0050] The sample volume is 30 μl, and the area of ​​the flow channel is 4 cm 2 However, when the sample volume is large, for example, when a 90 μl sample is introduced and measured, the area of ​​the flow channel region is tripled to 12 cm 2 In this case, too, if the area of ​​the margin seen from the opening side of the cover is 50% or more of the area of ​​the flow path region seen from the opening side of the cover, the sample can be absorbed with ease.

[0051] In particular, when an analytical device is used in which a working electrode is present in the introduction section and the contact angle of the exposed surface (reaction area) of the working electrode is 50° or more, the sample remains on the working electrode, and therefore contamination by the sample can be reduced by configuring the analytical device according to the present invention.

[0052] <Electrolyte concentration measurement method> An electrolyte concentration measurement method according to one embodiment of the present invention is a method for measuring electrolyte concentration using an analytical device according to the present invention, and includes the steps of introducing a sample into the analytical device to measure the electrolyte concentration and transporting the analytical device after measurement to a disposal position provided with a disposal unit, in which the first analytical device after measurement that was transported earlier and the second analytical device after measurement that was transported later are arranged in the disposal unit so that the opening of one analytical device and the uncovered area of ​​the margin of the other analytical device are in contact or close proximity. The disposal unit refers to, for example, a trash can for disposing of analytical devices, and may be a part of the analytical device or a separate component from the analytical device.

[0053] In this example, a procedure for manually moving the analytical device, measuring electromotive force, and measuring electrolyte concentration will be described. Figures 4 and 5 are schematic diagrams showing the method for measuring electrolyte concentration in this example. Figure 6 is a schematic diagram showing the method for disposing of the analytical device after electrolyte concentration measurement in this example. Note that in Figures 4 and 5, the portion covered by the cover 9 is indicated by a dotted line, and in Figure 6, the portion covered by the cover 9 is not shown. (1) The analytical device 100 is held at the portion where the cover 9 is provided with tweezers or the like and placed on the measurement table 202 as shown in Fig. 4. The electrode 203 of the measurement unit 201 that performs electromotive force measurement is connected to the lead wire 8a of the reference electrode 5 and the lead wire 8b of the working electrode 6 to prepare for electromotive force measurement. (2) As shown in FIG. 5, 30 μl of the specimen 11 is collected from the specimen ampoule (not shown) into the drop-dispensing syringe 204, and the entire amount of 30 μl is introduced dropwise into the introduction part (opening 9 a) of the analytical device 100. (3) In this embodiment, the introduction section and the working electrode 6 are integrated, and the reference electrode 5 is wetted with the sample 11, which flows from the second flow path chamber 2 around the working electrode 6 through the connecting flow path 3 and the first flow path chamber 1. Then, a time is allowed to elapse until the equilibrium reaction (the above formula (*)) that generates an electromotive force between the working electrode 6 and the reference electrode 5 stabilizes (in this embodiment, a time is allowed to elapse after dropping for 60 seconds). (4) Using the measuring unit 201 prepared in (1), the electromotive force value after 60 seconds is recorded and converted into the actual ion concentration. (5) As shown in Figure 6, the analytical device 100 after measurement is again grasped with tweezers or the like and disposed of in a disposal box 205, which is a disposal section. The worker carries the analytical device 100 to a disposal position 206, for example, directly above the disposal box 205, and drops the analytical device 100 into the disposal box 205. In the disposal box 205, the analytical device 100 after measurement that was carried earlier (first analytical device) and the analytical device 100 that was carried later (second analytical device) are stacked one on top of the other. The exposed absorption section 12 (porous section) of one analytical device 100 comes into contact with the droplets of sample 11 on the other analytical device 100 (indicated by a dotted circle), and the droplets of sample 11 are absorbed.

[0054] As described above, an analytical device in which the specimen is less likely to accumulate at the bottom of the disposal section and is less likely to scatter to the outside, and an electrolyte concentration measuring method using the same have been implemented.

[0055] [Example 2] An analytical device according to another embodiment of the present invention is an analytical device having a porous substrate formed of a porous material, wherein a flow path wall is formed inside the porous substrate from a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a marginal portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow path chamber has a reference electrode, the second flow path chamber has a working electrode, and the working electrode contains a hydrophobic material, and hydrophobic covers are provided on both sides of the porous substrate, and the covers are provided with an opening for introducing a sample, which is connected to the second flow path chamber, and the covers are provided so as to cover at least the flow path region except for the opening, and the area of ​​the marginal portion as viewed from the opening side is set to A mm 2 The thickness of the margin is T mm, the porosity of the margin is P, and the amount of sample introduced is S mm 3 Then, A×T×P≧S×0.33 and the marginal portion has an area that is not covered by the cover.

[0056] In this example, an example is shown in which the area of ​​the marginal portion that absorbs droplets of sample is estimated according to the amount of sample introduced. The area of ​​the marginal portion will be described below using the analytical device 100.

[0057] The amount of sample required for testing is determined by the measurement item and measurement method, but when the sample amount is large, the area of ​​the flow path region and the area of ​​the required margin also increase proportionally, so the area of ​​the required margin can be estimated from the amount of sample introduced. In addition, by taking into account the thickness and porosity of the margin, the area of ​​the margin can be estimated more accurately.

[0058] (Space for absorbing the sample) -Features and effects of this embodiment- A marginal portion 10 for absorbing the sample is provided as in Example 1. In this example, the relationship between the amount of sample and the area of ​​the marginal portion, etc. is shown.

[0059] The area of ​​the margin seen from the opening side (the top side where the sample is introduced) is A mm 2 , the thickness of the margin is T mm, the porosity of the margin is P, and the amount of sample introduced is S mm 3 (=μl), A×T×P≧S×0.33 The above relational expression is satisfied.

[0060] A specific calculation example is shown below. In this example, 30 μl of sample is dropped. With the expected area of ​​the flow path region in an analytical device used to measure this amount of sample, approximately 10 μl of this cannot be sufficiently retained within the porous substrate S1 of the analytical device 100, posing a risk of contaminating the surrounding area when the analytical device 100 is discarded. It can be estimated that the amount of sample to be absorbed is 33% or more of the amount of sample introduced. In this example, the thickness T of the marginal portion 10 (porous substrate S1) of the analytical device 100 is 0.1 mm, and the porosity P is 0.5. A×T×P≧S×0.33 Transform it into A≧S×0.33 / (T×P) Substituting numerical values, A≧30mm 3 ×0.33 / (0.1mm×0.5) From the above, about 200 mm 2 It can be estimated that a margin area of ​​1000 mm will be required.

[0061] [Example 3] Furthermore, an analytical device according to another embodiment of the present invention is an analytical device having a porous substrate formed of a porous material, wherein a flow path wall is formed inside the porous substrate from a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow path chamber has a reference electrode, and the second flow path chamber has a working electrode, the working electrode containing a hydrophobic material, and hydrophobic covers are provided on both sides of the porous substrate, and the covers are provided with an opening for introducing a sample, which is connected to the second flow path chamber, and the covers are provided so as to cover at least the flow path region except for the opening, and the maximum volume of a droplet of the sample remaining on the exposed surface of the working electrode at the opening is defined as V max mm 3 , the area of ​​the margin seen from the opening side is A mm 2 , the thickness of the margin is T mm, and the porosity of the margin is P, V max ≦A×T×P and the marginal portion has an area that is not covered by the cover.

[0062] In this example, an example is shown in which the required area of ​​the margin 10 is estimated from the relationship between the maximum volume of the sample droplet remaining on the exposed surface of the working electrode (corresponding to the size of the exposed surface 6a (reaction region) of the working electrode 6) and the required area of ​​the margin 10 for the analytical device 100. This can be said to be a more accurate estimation than Examples 1 and 2.

[0063] (Space for absorbing the sample) -Features and effects of this embodiment- As in Examples 1 and 2, a margin 10 is provided for absorbing the sample 11, but in this example, the area of ​​the margin 10 can be estimated from the volume of the droplet of sample 11 remaining on the working electrode 6.

[0064] When the analyte 11 is introduced onto the exposed surface 6a of the hydrophobic working electrode 6, and part of the analyte 11 permeates the flow path region and part is retained as droplets on the exposed surface 6a of the working electrode 6, droplets of the analyte 11 remain on the exposed surface 6a of the working electrode 6 even after the measurement is completed. These droplets of the analyte 11 remaining on the exposed surface 6a are the main target to be absorbed by the analytical device 100 (they are likely to contaminate the surrounding area when disposed of, etc.).

[0065] Furthermore, the amount of analyte 11 remaining on the exposed surface 6a of the working electrode 6 is related to the size and contact angle of the exposed surface 6a of the working electrode 6. Furthermore, the contact angle also changes depending on the properties of the analyte. If the analyte is water-soluble, the amount of analyte remaining is greatest when the contact angle is greatest. In other words, the maximum volume V of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 can be calculated from the contact angle of the exposed surface 6a of the working electrode 6. max (mm 3 ) can be calculated.

[0066] Four calculation examples are shown below. Two cases are shown: when the exposed surface 6a of the working electrode 6 at the opening 9a is circular and when it is square. For each case, the contact angle of a droplet of analyte 11 on the exposed surface 6a is 100° and 90°. The contact angle refers to the angle formed between a droplet of liquid dropped on a solid surface and the solid surface, and can be determined by, for example, the A half-angle method (θ / 2 method) or the tangent method.

[0067] (When the exposed surface of the working electrode is circular and the contact angle is 100°) The volume of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 at the opening 9a is determined in relation to the area and contact angle of the exposed surface 6a of the working electrode 6. First, the maximum volume of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 will be described when the contact angle θ of the hydrophobic exposed surface 6a is 100°. FIG. 8 shows a perspective view of the analytical device 100 when the analyte 11 is introduced, FIG. 9(a) shows a top view of the analytical device 100 before the introduction of the analyte 11, and FIG. 9(b) shows a top view of the analytical device 100 after the introduction of the analyte 11. In this example, the second flow chamber 2 is approximately circular, and the exposed surface 6a (reaction area) of the working electrode 6 in the second flow chamber 2 is also approximately circular. The opening 9a of the cover 9 has the same shape as the second flow chamber 2. Since the configurations of the second flow chamber 2, the working electrode 6, and the opening 9a are the same as those of Example 1, a description thereof will be omitted.

[0068] In this embodiment, when a droplet of analyte 11 is introduced, the circular exposed surface 6a is in a stable state when covered with a spherical droplet having a bottom surface of the same shape as the circular exposed surface 6a as shown in Figures 9(a) and 9(b), and the volume of the droplet of analyte 11 remaining on the exposed surface 6a at this time is at its maximum. Figure 7 shows a simplified view of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6. The shape parameters of the droplet are 2r (mm), h (mm), and V (mm), respectively. max (mm 3 ) and the contact angle is θ (°). In this example, the radius of the circle of the exposed surface 6a of the working electrode 6 is 1.5 mm.

[0069] Assuming that the droplet is a part of a sphere, the diameter r of the droplet is x (mm 2 ), then r = (√x) / (√π).

[0070] The following formula is obtained from the A half-angle method, which is generally used to measure contact angles.

number

[0071] Since tan50°=1.19, h=1.19×r This can be expressed as:

[0072] The volume of a part of a sphere, the spherical cap, is expressed by the following equation:

number

[0073] Eliminating h and r and expressing it using x, we get

number

[0074] In addition, assuming that droplets are absorbed by the marginal area (porous area), the absorption capacity differs depending on the thickness and porosity. The thicker and more porosity the marginal area (porous area) is, the better it absorbs. The maximum volume of the droplet of sample remaining on the exposed surface of the working electrode is defined as V. max (mm 3 ), the area of ​​the margin is A (mm 2 ), the thickness of the margin is T (mm), and the porosity is P. V max ≦A×T×P (2) If the pressure is increased, the droplets of the specimen 11 can be absorbed sufficiently. From equations (1) and (2), the required area A of the margin is

number

[0075] In this example, the thickness T of the marginal portion 10 is 0.1 mm, the porosity P is 0.5, and the area of ​​the exposed surface 6a of the working electrode 6 is 1.5×1.5×π mm 2 Therefore, the area x of the exposed surface 6a of the working electrode 6 is 7.1 mm 2 From equation (1), the volume of the droplet V max =9.3mm 3 The actual volume of the sample introduced is 30 μl = 30 mm 3 and the volume of the droplet V max 30-9.3mm excluding3 The sample is used for permeation into the flow path area. The amount of sample remaining on the exposed surface 6a of the working electrode 6 can be measured by sucking it up with a pipette.

[0076] The area A required for the margin 10 is approximately 185 to 186 mm according to formula (3). 2 By ensuring this, excess sample droplets can be absorbed.

[0077] (When the exposed surface of the working electrode is circular and the contact angle is 90°) An example is shown in which the contact angle of the exposed surface 6a of the working electrode 6 is 90°. In this example, as in the previous example, the exposed surface 6a of the working electrode 6 is circular with a radius of 1.5 mm. As in the previous example, refer to Figures 8, 9(a), and 9(b). The shape of a stable droplet of analyte 11 (a droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6) has a contact angle of 90°, so it has half the volume of a sphere with the same radius as the exposed surface 6a of the working electrode 6. At this time, the volume of the droplet of analyte 11 remaining on the exposed surface 6a is at its maximum. This is half the volume of a sphere with a radius of 1.5 mm.

[0078] Therefore, the volume V of the droplet is the area x (mm 2 ) and

number

[0079] As in the previous example, the maximum volume of the sample droplet remaining on the exposed surface of the working electrode is defined as V max (mm 3 ), the area of ​​the margin is A (mm 2 ), the thickness of the margin is T (mm), and the porosity is P. V max ≦A×T×P (2) If the pressure is sufficient, the droplets can be absorbed.

[0080] From equation (4) and equation (2), the required area A of the margin is

number

[0081] In this example, the thickness T of the marginal portion 10 is 0.1 mm, the porosity P is 0.5, and the area of ​​the exposed surface 6a of the working electrode 6 is 1.5×1.5×π mm 2 Therefore, the area x of the exposed surface 6a of the working electrode 6 is 7.1 mm 2 , droplet volume V = 7.1 mm 3 The actual volume of the sample introduced is 30 μl = 30 mm 3 30-7.1 mm excluding the volume V of the droplet 3 The sample is used for permeation within the flow area. The area A required for the margin 10 is approximately 141 mm 2 By ensuring this, excess sample droplets can be absorbed.

[0082] (When the exposed surface of the working electrode is square and the contact angle is 100°) An example in which the exposed surface 6a of the working electrode 6 is square-shaped is shown. Fig. 10 is a perspective view of the analytical device 100 when a sample 11 is introduced, Fig. 11(a) is a top view of the analytical device 100 before the sample is introduced, and Fig. 11(b) is a top view of the analytical device 100 after the sample is introduced. In this example, the second flow channel chamber 2 is approximately square-shaped, and the exposed surface 6a (reaction area) of the working electrode 6 in the second flow channel chamber 2 is also approximately square-shaped. The opening 9a of the cover 9 has the same shape as the second flow channel chamber 2. Other parts are the same as those in Example 1, and therefore description thereof will be omitted.

[0083] When the exposed surface 6a of the working electrode 6 is square, if a sufficient amount of analyte 11 is introduced, the bottom of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 will be the inscribed circle of the square, and the volume of the droplet of analyte 11 remaining on the exposed surface 6a will be maximum. As in the above example, as shown in Figure 7, the radius of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 will be r, the height will be h, and the volume will be V. max The contact angle is θ, and the droplet is assumed to be a part of a sphere. The diameter of the droplet, 2r, is calculated by dividing the square area of ​​the exposed surface 6a of the working electrode 6 by y (mm 2 ), then 2r=√y.

[0084] As above, the following equation is obtained from the A half-angle method, which is generally used to measure contact angles.

number

[0085] The volume of a part of a sphere, the spherical cap, is expressed by the following equation:

number

[0086] Eliminating h and r and expressing it using y,

number

[0087] As in the previous example, the volume of the sample droplet remaining on the exposed surface of the working electrode is V max (mm 3 ), the area of ​​the margin is A (mm 2 ), the thickness of the margin is T (mm), and the porosity is P. V max ≦A×T×P (2) If the pressure is sufficient, the droplets can be absorbed. Therefore, the area A of the required margin 10 is

number

[0088] In this example, the thickness T of the marginal portion 10 is 0.1 mm, the porosity P is 0.5, and the area of ​​the exposed surface 6a of the working electrode 6 is 3×3 mm 2 Therefore, the area of ​​the exposed surface 6a of the working electrode 6 is y = 9 mm 2 From equation (6), the volume of the droplet V max =9.3mm 3 The actual volume of the sample introduced is 30 μl = 30 mm3 and the volume of the droplet V max 30-9.3mm excluding 3 The sample is used for permeation within the flow path area. The area A required for the margin 10 is approximately 186 mm 2 This is all, and by ensuring this, excess droplets of the specimen 11 can be absorbed.

[0089] (When the exposed surface of the working electrode is square and the contact angle is 90°) As in the previous example, an example is shown in which the exposed surface 6a of the working electrode 6 is square-shaped. As in the previous example, refer to Figures 10 and 11. When the exposed surface 6a of the working electrode 6 is square-shaped, if a sufficient amount of analyte 11 is dropped, the bottom of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 forms the inscribed circle of the square, and at this time, the volume of the droplet of analyte 11 remaining on the exposed surface 6a of the working electrode 6 is at its maximum. In this case, because the contact angle of the droplet is 90°, it is half the size of a sphere with a radius equal to the inscribed circle of the square. In other words, it has half the volume of a sphere with a radius of 1.5 mm.

[0090] Therefore, the area of ​​the exposed surface 6a of the working electrode 6 is defined as y mm 2 Then, the maximum volume V of the droplet of the sample 11 remaining on the exposed surface 6a of the working electrode 6 is max teeth

number

[0091] As in the previous example, the volume of the sample droplet remaining on the exposed surface of the working electrode is V max (mm 3 ), the area of ​​the margin is A (mm 2 ), the thickness of the margin is T (mm), and the porosity is P. V max ≦A×T×P (2) If the pressure is sufficient, the droplets can be absorbed. Therefore, the required area A of the margin is

number

[0092] In this example, the thickness of the marginal portion 10 is 0.1 mm, the porosity is 0.5, and the area of ​​the exposed surface 6a of the working electrode 6 is 3×3 mm 2 Therefore, the area of ​​the exposed surface 6a of the working electrode 6 is y = 9 mm 2 From equation (8), the volume of the droplet V max =7.1mm 3 The actual volume of the sample introduced is 30 μl = 30 mm 3 and the volume of the droplet V max 30-7.1mm excluding 3 The sample is used for permeation within the flow area. The area A required for the margin 10 is approximately 141 mm 2 This is all, and by ensuring this, excess specimen 11 can be absorbed.

[0093] [Example 4] An electrolyte concentration measurement method according to one embodiment of the present invention is a method for measuring electrolyte concentration using an analytical device according to the present invention, and comprises the steps of introducing a sample into the analytical device to measure the electrolyte concentration, and transporting the analytical device after measurement to a disposal position provided with a disposal section, and is characterized in that after the measurement step, the method comprises at least one of the following steps (i) to (iii):

[0094] (i) before the step of transporting the analytical device to a disposal position, a step of tilting the analytical device by 30 to 80 degrees from a direction horizontal to the ground so that an area not covered by the marginal cover is present below the opening; (ii) during the step of transporting the analytical device to a disposal position, tilting the analytical device by 30 to 80 degrees from a direction horizontal to the ground so that an area not covered by the marginal cover is present below the opening; and (iii) After the step of transporting the analytical device to a disposal position, a step of tilting the analytical device by 30 to 80 degrees relative to a direction horizontal to the ground so that there is an area below the opening that is not covered by the margin cover.

[0095] In this example, a method for recovering droplets more reliably is proposed. Unless otherwise specified, the same applies as in Example 1.

[0096] <Differences in analytical device shapes> The analytical device according to the present invention can have an area on the same surface as the surface on which the opening is provided that is not covered by the marginal cover. Figures 12(a) to 12(d) show schematic diagrams of an analytical device 300 according to this example. Figure 12(a) is a top view of the analytical device 300 before lamination, Figure 12(b) is a top view of the analytical device 300 after lamination, Figure 12(c) is a cross-sectional view taken along line BB' in Figure 12(b), and Figure 12(d) is a perspective view of the analytical device 300.

[0097] The analytical device 300 has a porous substrate S3 on which a first flow path chamber 31, a second flow path chamber 32, a connecting flow path 33, a flow path wall 34, a reference electrode 35, a working electrode 36, an ion crystal 37, lead wires 38a and 38b, a margin 30, and a cover 39 are formed. An opening 39a is provided in the cover 39, and an exposed surface 36a of the working electrode 36 is exposed. The shape of the analytical device 300, the configuration of the flow path region, and the electrode formulation are the same as those of the analytical device 100 of Example 1, except for the shape of the absorption section, and therefore will not be described again.

[0098] By changing the shape of the cover 39, the shape of the absorption section 312 is changed from that of Example 1. The area of ​​the marginal portion is the same as that of Example 1, and a portion of one side of the analytical device 300 (in this example, the top surface where the opening 39a for introducing the sample is provided) is not covered with laminate but is left exposed and serves as the absorption section 312. In this example, the cover 39 is positioned to one side, and the absorption section 312 is positioned to the other side. As in Example 1, the porous portion (the area of ​​the marginal portion 30 not covered by the cover 39) provided on the side of the analytical device 300 as the absorption section 312 can also absorb droplets of the sample 11. Note that in Figures 12(a) and 12(b), the portions covered with the ion crystals 37 and the cover 39 are indicated by dotted lines, and in Figure 12(d), the portion covered by the cover 39 is not shown.

[0099] Alternatively, the lamination method may be such that the margin surrounds the periphery of the cover. An analytical device 400 having a margin surrounding the periphery of the cover is shown in FIGS. 13(a) to 13(d). FIG. 13(a) is a top view of the analytical device 400 before lamination, FIG. 13(b) is a top view of the analytical device 400 after lamination, FIG. 13(c) is a cross-sectional view taken along line CC' in FIG. 13(b), and FIG. 13(d) is a perspective view of the analytical device 400. The analytical device 400 includes a porous substrate S4, a first flow channel chamber 41, a second flow channel chamber 42, a connecting flow channel 43, a flow channel wall 44, a reference electrode 45, a working electrode 46, an ion crystal 47, lead wires 48a and 48b, a margin 40, and a cover 49. An opening 49a is provided in the cover 49, exposing the exposed surface 46a of the working electrode 46. An absorption section 412 is provided so as to surround the periphery of the cover 49. As in Example 1, the porous section (the area of ​​the margin section 40 not covered by the cover 49) provided on the side of the analytical device 400 as the absorption section 412 can also absorb droplets of the specimen 11. The shape of the analytical device 400, the configuration of the flow path region, and the electrode formulation are the same as those of the analytical device 100 of Example 1, except for the shape of the absorption section. Note that in Figures 13(a) and 13(b), the parts covered by the ion crystals 47 and the parts covered by the cover 49 are indicated by dotted lines, and in Figure 13(d), the parts covered by the cover 49 are not shown.

[0100] <Differences in electrolyte concentration measurement methods> See Figures 14 and 15. After measuring the electromotive force as in Example 1, the laminated portion of the analytical device is held with tweezers and tilted diagonally. This allows droplets to flow onto the exposed margin (absorbent portion) not covered by the cover, allowing the sample to be absorbed by the absorbent portion. In Figures 14 and 15, the droplets of sample 11 flow in the direction of the arrow and are absorbed, for example, in the area surrounded by the dotted circle. As shown in Figure 14, if the absorbent portion 312 is tilted, the sample can be easily absorbed even if the tilt is steep. As shown in Figure 15, if the absorbent portion 412 is shaped to surround the droplet of sample 11, absorption is possible regardless of the tilt direction. The tilt angle can be selected based on the appropriate advantages. In this example, it is preferable to tilt the analytical device 30 to 80 degrees relative to the horizontal direction. An angle of 30 degrees or more relative to the horizontal direction allows the sample to flow easily, while an angle of 80 degrees or less allows for easy absorption. Finally, the analytical device is carried to the disposal position and disposed of in a disposal box, which is the disposal section, to complete the measurement. In this case, the disposal position can be, for example, directly above the disposal box. This allows the sample to be disposed of in a state where it has been sufficiently absorbed.

[0101] [Example 5] In this example, a method for more efficiently collecting droplets of a specimen is proposed. Unless otherwise specified, the same applies as in Example 1.

[0102] <Differences in analytical device shapes> The analytical device according to one embodiment of the present invention may have an area on the side opposite to the side on which the opening is provided that is not covered by a marginal cover. In this case, the analytical device may have at least a portion of the same side as the side on which the opening is provided and at least a portion of the side opposite to the side on which the opening is provided that is not covered by a cover.

[0103] In this example, the shape of the absorption section (the area of ​​the marginal portion not covered by the cover) is changed from that of Example 1. See Figures 16(a) to 16(d). Figure 16(a) is a top view of the analytical device 500 before lamination, Figure 16(b) is a top view of the analytical device 500 after lamination, Figure 16(c) is a cross-sectional view taken along the line D-D' in Figure 16(b), and Figure 16(d) is a perspective view of the analytical device 500. The analytical device 500 includes a porous substrate S5 on which a first flow path chamber 51, a second flow path chamber 52, a connecting flow path 53, a flow path wall 54, a reference electrode 55, a working electrode 56, an ion crystal 57, lead wires 58a and 58b, a cover 59, and a marginal portion 50 are formed. An opening 59a is provided in the cover 59, exposing the exposed surface 56a of the working electrode 56. An absorption section 512 is provided to surround the periphery of the cover 59. As in Example 1, the porous portion (the area of ​​the margin portion 50 not covered by the cover 59) provided on the side of the analytical device 500 as the absorbing portion 512 can also absorb droplets of the specimen 11. The shape of the analytical device 500, the configuration of the flow path region, and the electrode formulation are the same as those of the analytical device 100 of Example 1, except for the shape of the absorbing portion.

[0104] The area of ​​the marginal portion is the same as in Example 1, and part of the marginal portion 50 on the surface of the analytical device 500 is exposed and not covered with the cover 59 on both sides (the same side as the side on which the opening 59a is provided and the opposite side) to form the absorption portion 512.

[0105] <Differences in electrolyte concentration measurement methods> After measuring the electromotive force as in Example 1, the cover 59 of the analytical device 500 is grasped with tweezers, and the analytical device 500 is carried to the disposal position 206 as shown in FIG. 17, and disposed of in the disposal box 205, completing the measurement. As shown in FIG. 17, the analytical devices 500 overlap each other when disposed of. Therefore, by providing areas (absorption sections 512) on both sides that are not covered by the cover 59, the opportunities for absorbing droplets of the sample 11 on another analytical device 500 are increased compared to Example 1 (examples of absorption locations are shown by dotted circles). This allows the analytical device to efficiently absorb the sample, improving safety during disposal.

[0106] [Example 6] Furthermore, an analytical apparatus according to one embodiment of the present invention may include an analytical device according to the present invention, a measurement unit connected to the analytical device, which measures the electromotive force based on the potential difference between the reference electrode and the working electrode to measure the electrolyte concentration of the sample, and a disposal unit which transports the analytical device to a disposal position after measurement. The disposal unit may be, for example, a conveying member such as an arm or a belt. The disposal unit may be capable of tilting the analytical device by 30 to 80 degrees relative to a direction horizontal to the ground so that an area not covered by the marginal cover is present below the opening.

[0107] In Examples 1, 4, and 5, a method for manually moving and disposing of an analytical device with a modified absorption section was described. As another example, an example of an automatic method for moving an analytical device is shown. In this example, the analytical device 300 described in Example 4 (FIGS. 12(a) to (d)) is used. Unless otherwise specified below, the other configurations are the same as in Example 4.

[0108] <Analyzer and Electrolyte Concentration Measurement Method> 18, the analysis apparatus A1 according to this embodiment has a belt 207 as a disposal unit that transports the analytical device 300 after measurement to a disposal position 206 provided with a disposal section (disposal box 205). When transporting the analytical device 300 after measurement to the disposal position 206, the belt 207 can tilt the analytical device 300 by 30 to 80 degrees relative to a direction horizontal to the ground so that an area (absorbent section 312) not covered by the marginal cover is present below the opening 39a.

[0109] A method for measuring the electrolyte concentration using the analyzer A1 will be described with reference to Figures 18 to 20. In Figures 19 and 20, the portion covered by the cover 39 is indicated by dotted lines. (1) The analytical devices 300 are stored in the stocker 208. The stocker 208 is provided with an incline, and a roller that can be rotated by a drive source (not shown) is provided at the exit of the stocker 208, and the analytical devices 300 are fed out one by one. (2) The measurement stage 202 is integrated with a belt (conveying member) 207 that can be rotated by power from a drive source (not shown). In synchronization with the delivery of the analytical device 300 from the rollers, the analytical device 300 is placed on the rotatable belt 207, which rotates and conveys it, and fixes it at the measurement position (the direction of belt movement is indicated by an arrow in the figure). In this example, a belt is used as the conveying member, but it is not limited to a belt. (3) Next, as shown in Figures 18 and 19, the electrode 203 of the measurement unit 201 (driven in the direction of the arrow) is placed in a position where it will be connected to the lead wires 38b and 38a of the working electrode 36 and the reference electrode 35 by a driving source (not shown), and preparations for electromotive force measurement are made. (4) Next, as shown in Figures 18 and 20, 30 µl of specimen is collected from a specimen ampule (not shown) into a drop-dispensing syringe 204 (driven in the direction of the arrow (up, down, left, right)) by a drive source and air source (not shown), and the entire amount is introduced dropwise into the introduction section (opening 39a) of the analytical device 300. After introduction, the drop-dispensing syringe 204 is retracted. For ease of explanation, the measurement unit 201 is not shown in Figure 20. In this embodiment, the introduction portion (opening 39a) and the working electrode 36 are integrated. The reference electrode 35 is wetted with the sample 11, which flows from the second flow path chamber 32 around the working electrode 36 through the connecting flow path 33 and the first flow path chamber 31. Then, a time is allowed to elapse until the equilibrium reaction (formula (*)) that generates an electromotive force between the working electrode 36 and the reference electrode 35 stabilizes (in this embodiment, a time is allowed to elapse after dropping for 60 seconds). (5) The measurement unit 201 prepared in (3) records the electromotive force value after 60 seconds and converts it into the actual ion concentration. After the measurement, the measurement unit 201 is removed. (6) The transport is resumed using the measurement stage 202 equipped with the rotatable belt 207. As shown in FIG. 21(a), the belt 207 is transported while tilted 30 to 80 degrees from the horizontal direction to the ground using, for example, a movable stage 209 (movable in the direction of the arrow) so that the absorbing unit 312 is located below the opening 39a of the analytical device 300. By intentionally tilting the analytical device 300 as shown in FIG. 21(b), droplets of the specimen 11 flow in the direction indicated by the arrow in the figure and are absorbed by the absorbing unit 312. The tilt angle is set to the extent that the droplets spread, and in this example, it was set to 45 degrees. In this example, an angle of 30 degrees or more facilitated the droplets to flow, while an angle of 80 degrees or less facilitated absorption to keep up with the droplet flow. In this way, by bringing the droplets of the specimen 11 into contact with the absorbing unit 312, the analytical device 300 can absorb and collect the droplets while transporting them on the belt 207. (7) Finally, at the disposal position 206 (for example, directly above the disposal box 205), the analytical device 300 is dropped from the belt 207 and discarded. Since the droplets of the sample were sufficiently absorbed in the above step (6), the risk of droplet scattering was reduced.

[0110] [Example 7] An electrolyte concentration measurement method according to one embodiment of the present invention is a method for measuring electrolyte concentration using an analytical device according to the present invention, comprising the steps of introducing a sample into the analytical device to measure the electrolyte concentration and transporting the analytical device after measurement to a disposal position provided with a disposal unit, wherein the disposal unit has a sloped bottom, and the analytical device after measurement is placed in the disposal unit at an angle of 30 to 80 degrees relative to a direction horizontal to the ground so that an area not covered by the marginal cover is present below the opening. Furthermore, an analytical apparatus according to one embodiment of the present invention can be an analytical apparatus further comprising a disposal unit having a bottom surface sloped at an angle of 30 to 80 degrees relative to a direction horizontal to the ground, and the disposal unit transports the analytical device to the disposal position provided with the disposal unit.

[0111] In Example 6, the analytical device was tilted by tilting the belt, which is the disposal unit. In this example, an example is shown in which the analytical device is tilted at an angle in the disposal unit.

[0112] In this example, the analytical device 300 described in Example 4 (FIGS. 12(a) to 12(d)) is used, as in Example 6. Hereinafter, the configuration and steps of the analytical device are the same as those in Example 6 unless otherwise specified. Specifically, steps (1) to (5) of the <electrolyte concentration measurement method> described in Example 6 are carried out, and then the measurement is carried out with the following modifications.

[0113] <Changes in electrolyte concentration measurement method> (6) The process of transporting the analytical device uses a horizontal belt 207. (An angle-adjustable belt is not necessary.) (7) See FIG. 22. After the belt 207 for disposal releases the analytical device 300 at the disposal position 206 (for example, directly above the waste box 205, which is the disposal section), the analytical device 300 is adjusted so that it strikes the drop direction adjustment bar 210. This allows the droplets of the specimen 11 to fall at an angle in the direction of the arrow in the figure, so that they are directed toward the absorption section 312. Furthermore, the bottom surface 205a of the waste box 205 is angled so that the droplets of the specimen 11 are directed in the direction of the arrow in the figure. Even after the analytical device 300 lands on the bottom of the waste box 205, the droplets continue to be absorbed by the absorption section 312 (shown by the dotted circle in the figure). In this example, the angle of the bottom surface 205a was set to 45 degrees with respect to the horizontal direction. In this example, an angle of 30 degrees or more made it easier for the droplets of the specimen 11 to flow, while an angle of 80 degrees or less made it easier for the absorption to keep up with the flow of the droplets. In this way, the sample 11 was sufficiently absorbed into the analytical device 300 and discarded.

[0114] [Example 8] This example uses the analytical device described in Example 6 above, and shows an example of efficiently absorbing droplets using the analytical device. The analytical device used can be any of the analytical device 100 described in Example 1, the analytical device 300, the analytical device 400, and the analytical device 500 described in Example 4, but in this example, the analytical device 300 is used. Hereinafter, the configuration and steps of the analytical device are the same as in Example 6 unless otherwise specified. Specifically, steps (1) to (5) of the <electrolyte concentration measurement method> described in Example 6 are performed, and then the measurement is carried out with the following modifications.

[0115] <Changes in electrolyte concentration measurement method> (6) The transport process uses a horizontal belt 207 (a belt with adjustable angle is not necessary). On the other hand, the belt 207 is configured to have multiple positions available as release positions (disposal positions 206) for the analytical device 300. (7) When the belt 207 releases the analytical device 300 during disposal, the disposal position 206 is adjusted so that the absorption part 312 of the analytical device 300 to be discarded hits droplets of the specimen 11 on another analytical device 300 that has already been discarded. In other words, the state shown in Figures 6 and 17 is realized by mechanical control of the belt 207. This allows, for example, droplets on an analytical device that has fallen earlier to be absorbed by the absorption part of an analytical device that has fallen later.

[0116] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; an area of ​​the marginal portion as viewed from the opening side is 50% or more of an area of ​​the flow path region as viewed from the opening side; An analytical device, wherein the marginal portion has an area not covered by the cover. (Configuration 2) An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The area of ​​the marginal portion as viewed from the opening side is A mm 2 The thickness of the marginal portion is T mm, the porosity of the marginal portion is P, and the amount of the sample introduced is S mm 3 Then, A×T×P≧S×0.33 The following relation is satisfied: The analysis device is characterized in that the marginal portion has an area that is not covered by the cover. (Configuration 3) An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The maximum volume of the droplet of the sample remaining on the exposed surface of the working electrode at the opening is defined as V max mm 3 , the area of ​​the marginal portion as viewed from the opening side is A mm 2 , where the thickness of the marginal portion is T mm and the porosity of the marginal portion is P, V max ≦A×T×P The following relation is satisfied: The analysis device is characterized in that the marginal portion has an area that is not covered by the cover. (Configuration 4) 4. The analytical device according to any one of configurations 1 to 3, wherein the contact angle of the exposed surface of the working electrode at the opening is 50° or more. (Configuration 5) 5. The analytical device according to any one of configurations 1 to 4, wherein the analytical device has a side surface having an area of ​​the margin that is not covered by the cover. (Configuration 6) 6. The analytical device according to any one of configurations 1 to 5, characterized in that the marginal portion has an area not covered by the cover on the same surface as the surface on which the opening is provided. (Configuration 7) 7. The analytical device according to any one of configurations 1 to 6, characterized in that the analytical device has an area of ​​the margin that is not covered by the cover on the surface opposite to the surface on which the opening is provided. (Method 8) A method for measuring an electrolyte concentration using the analytical device according to any one of configurations 1 to 7, a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, A method for measuring electrolyte concentrations, characterized in that, in the disposal section, the first analytical device after measurement that was transported earlier and the second analytical device after measurement that was transported later are arranged so that the opening of one is in contact with or close to the area of ​​the margin of the other that is not covered by the cover. (Method 9) A method for measuring an electrolyte concentration using the analytical device according to any one of configurations 1 to 7, a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, The method for measuring an electrolyte concentration comprises, after the step of performing the measurement, at least one of the following steps (i) to (iii): (i) before the step of transporting the analytical device to the disposal position, a step of tilting the analytical device by 30 to 80 degrees with respect to a direction horizontal to the ground so that an area of ​​the marginal portion not covered by the cover is present below the opening; (ii) during the step of transporting the analytical device to the disposal position, tilting the analytical device by 30 to 80 degrees from a direction horizontal to the ground so that an area of ​​the marginal portion not covered by the cover is present below the opening; and (iii) after the step of transporting the analytical device to the disposal position, a step of tilting the analytical device by 30 to 80 degrees relative to a direction horizontal to the ground so that an area of ​​the margin portion not covered by the cover is present below the opening. (Method 10) A method for measuring an electrolyte concentration using the analytical device according to any one of configurations 1 to 7, a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, The method for measuring an electrolyte concentration is characterized in that the disposal section has an inclined bottom surface, and after measurement, the analytical device is placed in the disposal section at an angle of 30 to 80 degrees from a direction horizontal to the ground so that an area of ​​the marginal portion not covered by the cover is present below the opening. (Configuration 11) The analytical device according to any one of configurations 1 to 7, a measurement unit connected to the analytical device, which measures an electromotive force based on the potential difference between the reference electrode and the working electrode, and measures the electrolyte concentration of the sample; and An analytical apparatus comprising a disposal unit that transports the analytical device to a disposal position after measurement. (Configuration 12) The analytical apparatus of configuration 11, wherein the disposal unit tilts the analytical device by 30 to 80 degrees relative to a direction horizontal to the ground so that an area of ​​the margin portion not covered by the cover is present below the opening. (Configuration 13) Further, the waste disposal unit has a bottom surface inclined at 30 to 80 degrees relative to a direction horizontal to the ground. 13. The analytical apparatus according to claim 11, wherein the disposal unit transports the analytical device to a disposal position where the disposal section is provided. [Explanation of symbols]

[0117] 1, 21, 31, 41, 51...First flow path chamber 2, 22, 32, 42, 52...Second channel chamber 3, 23, 33, 43, 53...connecting channels 5, 25, 35, 45, 55...Reference electrode 6, 26, 36, 46, 56... working electrode 9, 39, 49, 59…cover 10, 30, 40, 50...Margins 12, 312, 412, 512...Absorption sections

Claims

1. An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; an area of ​​the marginal portion as viewed from the opening side is 50% or more of an area of ​​the flow path region as viewed from the opening side; An analytical device, wherein the marginal portion has an area not covered by the cover.

2. An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The area of ​​the marginal portion as viewed from the opening side is A mm ２ The thickness of the marginal portion is T mm, the porosity of the marginal portion is P, and the amount of the sample to be introduced is S mm ３ Then, A x T x P ≥ S x 0.33 The following relation is satisfied: The analysis device is characterized in that the marginal portion has an area that is not covered by the cover.

3. An analytical device having a porous substrate formed of a porous material, A flow path wall is formed inside the porous substrate using a hydrophobic material, and the porous substrate is divided by the flow path wall into a flow path region surrounded by the flow path wall and a margin portion existing outside the flow path wall, the flow path region has a first flow path chamber, a second flow path chamber, and a connecting flow path connecting the first flow path chamber and the second flow path chamber, the first flow chamber having a reference electrode and the second flow chamber having a working electrode, the working electrode comprising a hydrophobic material; a hydrophobic cover is provided on both sides of the porous substrate, the cover is provided with an opening communicating with the second flow path chamber for introducing a sample, and the cover is provided so as to cover at least the flow path region except for the opening; The maximum volume of the droplet of the sample remaining on the exposed surface of the working electrode at the opening is defined as V ｍａｘ mm ３ , the area of ​​the marginal portion as viewed from the opening side is A mm ２ , where the thickness of the marginal portion is T mm and the porosity of the marginal portion is P, V ｍａｘ ≦A×T×P The following relation is satisfied: The analysis device is characterized in that the marginal portion has an area that is not covered by the cover.

4. 4. The analytical device according to claim 1, wherein the contact angle of the exposed surface of the working electrode at the opening is 50° or more.

5. The analytical device according to any one of claims 1 to 3, wherein the analytical device has a side surface including an area of ​​the margin that is not covered by the cover.

6. The analytical device according to any one of claims 1 to 3, characterized in that the marginal portion has an area not covered by the cover on the same surface as the surface on which the opening is provided.

7. The analytical device according to any one of claims 1 to 3, further comprising an area of ​​the margin that is not covered by the cover on a surface opposite to the surface on which the opening is provided.

8. A method for measuring an electrolyte concentration using the analytical device according to any one of claims 1 to 3, comprising: a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, A method for measuring electrolyte concentrations, characterized in that, in the disposal section, the first analytical device after measurement that was transported earlier and the second analytical device after measurement that was transported later are arranged so that the opening of one is in contact with or close to the area of ​​the margin of the other that is not covered by the cover.

9. A method for measuring an electrolyte concentration using the analytical device according to any one of claims 1 to 3, comprising: a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, A method for measuring an electrolyte concentration, comprising, after the step of performing the measurement, at least one of the following steps (i) to (iii): (i) before the step of transporting the analytical device to the disposal position, a step of tilting the analytical device by 30 to 80 degrees with respect to a direction horizontal to the ground so that an area of ​​the marginal portion not covered by the cover is present below the opening; (ii) during the step of transporting the analytical device to the disposal position, tilting the analytical device by 30 to 80 degrees with respect to a direction horizontal to the ground so that an area of ​​the marginal portion not covered by the cover is present below the opening; and (iii) After the step of transporting the analytical device to the disposal position, the analytical device is tilted 30 to 80 degrees from a direction horizontal to the ground so that an area of ​​the margin portion not covered by the cover is present below the opening.

10. A method for measuring an electrolyte concentration using the analytical device according to any one of claims 1 to 3, comprising: a step of introducing the sample into the analytical device to measure the electrolyte concentration; and a step of transporting the analytical device after measurement to a disposal position provided with a disposal unit, The method for measuring electrolyte concentration is characterized in that the disposal section has a slanted bottom surface, and after measurement, the analytical device is placed in the disposal section at an angle of 30 to 80 degrees relative to a direction horizontal to the ground so that an area of ​​the margin portion not covered by the cover is present below the opening.

11. The analytical device according to any one of claims 1 to 3, a measurement unit connected to the analytical device, which measures an electromotive force based on the potential difference between the reference electrode and the working electrode, and measures the electrolyte concentration of the sample; and An analytical apparatus comprising a disposal unit that transports the analytical device to a disposal position after measurement.

12. The analytical apparatus of claim 11, wherein the disposal unit tilts the analytical device by 30 to 80 degrees relative to a direction horizontal to the ground so that an area of ​​the margin that is not covered by the cover is present below the opening.

13. The waste disposal unit further has a bottom surface inclined at an angle of 30 to 80 degrees with respect to a direction horizontal to the ground, The analysis apparatus according to claim 11 , wherein the disposal unit transports the analysis device to a disposal position where the disposal section is provided.

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