CN115349088A - Electrochemical analysis chip - Google Patents

Abstract

The present invention provides an electrochemical analysis chip capable of measuring a plurality of items by one sampling. The electrochemical analysis chip (2) is provided with a sensor unit (22) and a channel unit (23), wherein the sensor unit (22) has a plurality of electrodes (242, 243, 244) and is provided on an insulating base material (21), and the channel unit (23) is provided on the base material (21) and guides a sample liquid to the sensor unit (22). A plurality of sensor sections (22) are provided on a base material (21). The flow path section (23) is provided with: a sample liquid supply port (231) that opens on the outer surface of the base material (21); and a sample liquid channel (232) for guiding the same sample liquid from the sample liquid supply port (231) to the plurality of sensor sections (22).

Description

Electrochemical Analysis Chip

technical field

The present invention relates to an electrochemical analysis chip for measuring the concentration of a specific substance that may be contained in a sample liquid.

Background technique

The measurement using the principle of electrochemical measurement is used in many scenarios: high-sensitivity measurement of heavy metals in solution, glucose measurement using an enzyme electrode, measurement of pH (hydrogen ion concentration index) using an ion electrode, electrochemical detection of residual pesticides Representative food inspection (for example, refer to Patent Document 1) and the like.

In electrochemical measurement, it is known that an electrochemical analysis chip in which electrodes are formed on an insulating substrate can be used. In the electrochemical analysis chip, the electrodes basically have a single-layer structure, and metal materials such as silver, platinum, gold, and aluminum or conductive materials such as carbon are used as electrode materials.

However, when measuring multiple items simultaneously using a conventional electrochemical analysis chip, it is necessary to perform a sampling operation for each of the multiple items. However, if the sampling operation is performed separately for multiple items, there will be problems such as concentration unevenness (concentration varies depending on the position of the sample specimen, the sampling site, the initial or intermediate, etc.), and the measurement accuracy and reproducibility will decrease. . In addition, there is a problem that a large amount of sample liquid is required to perform multiple sampling operations for the same sample liquid.

prior art literature

patent documents

Patent Document 1: Japanese Patent Application Laid-Open No. 11-248668

Contents of the invention

The problem to be solved by the invention

The present invention has been made to improve the above-mentioned present situation, and an object of the present invention is to provide an electrochemical analysis chip capable of measuring a plurality of items by one sampling operation.

solutions to problems

The electrochemical analysis chip of the present invention is an electrochemical analysis chip comprising a sensor unit having a plurality of electrodes and provided on an insulating base material, and a flow channel unit provided on the base material. The sample liquid is guided to the sensor part, and in the electrochemical analysis chip, a plurality of the sensor parts are provided on the base material, the flow path part has a sample liquid supply port and a sample liquid flow path, and the sample liquid The liquid supply port is opened on the outer surface of the substrate, and the sample liquid channel guides the same sample liquid from the sample liquid supply port to the plurality of sensor units.

According to the electrochemical analysis chip of the present invention, the same sample liquid can be guided from the sample liquid supply port to a plurality of sensor units through the sample liquid channel, and therefore, the same sample liquid can be brought into contact with the plurality of sensor units in one sampling operation. Thereby, even a trace amount of sample liquid can perform measurement of a plurality of items by one sampling operation.

In the electrochemical analysis chip of the present invention, the flow path section may include a plurality of sample liquid flow paths connected to one sample liquid supply port.

According to such a configuration, the sample liquid can be introduced into a plurality of sensor units by only bringing the sample liquid into contact with one sample liquid supply port, so that the sampling operation is easy and the time required for the sampling operation can be shortened.

In the electrochemical analysis chip according to the present invention, the channel unit may include the sample solution supply port and the sample solution channel for each of the plurality of sensor units. The two sample liquid supply ports are disposed close to each other on the outer surface of the substrate.

According to such a configuration, by providing the sample liquid supply port and the sample liquid flow path for each sensor portion, the sample liquid can be reliably introduced into each sensor portion. In addition, by arranging the sample liquid supply ports provided for each sensor unit close to each other on the outer surface of the base material, the sample liquid can be reliably brought into contact with these sample liquid supply ports in one sampling operation, and the reliability of the sampling process can be improved. .

In the electrochemical analysis chip of the present invention, the sensor unit may be provided on an electrode chip that can be attached to the base material, the base material includes an electrode chip arrangement part, and the electrode chip arrangement part is located at the base material. The outer surface of the base material is opened for the insertion of the electrode chip, the sample liquid flow path is connected to the electrode chip arrangement part, and an electrode chip is provided between the inner wall of the electrode chip arrangement part and the electrode chip. and a gap for the sample liquid to permeate from the sample liquid flow path toward the opening of the electrode chip arrangement part by capillary action.

According to such a configuration, it is possible to cope with many measurement items by exchanging the electrode chip according to the measurement items, so that the versatility is improved.

In the electrochemical analysis chip of the present invention, the substrate may be formed of a base substrate on which the sensor portion is formed, a flow path substrate on which the flow path portion is formed, and a cover covering the flow path substrate. It is constructed by stacking substrates.

According to such a configuration, it is possible to reduce the size of the electrochemical analysis chip by integrating the sensor unit and the base substrate.

In the electrochemical analysis chip of the present invention, the sensor unit may include a working electrode and a reference electrode or a working electrode, a reference electrode, and a counter electrode as the electrodes, and the electrodes may be formed on an insulating layer. a metal layer on a permanent substrate, a carbon layer formed on the substrate so as to cover the metal layer, and an upper adhesive layer formed between the upper surface of the metal layer and the carbon layer, the The upper adhesive layer is formed of silicon.

According to such a configuration, since each electrode has a metal layer, the electrical resistance is reduced, and the measurement sensitivity can be improved. In addition, by covering the metal layer with the carbon layer, oxidation and reduction of the metal layer can be prevented, and measurement sensitivity and reproducibility can be improved. Moreover, by providing an upper adhesive layer formed of silicon between the upper surface of the metal layer and the carbon layer, the adhesion between the metal layer and the carbon layer is improved, and since silicon has a higher resistivity than the metal, it is possible to suppress fluctuations in the measurement. The generation of hydrogen on the upper surface of the metal layer prevents the peeling of the metal layer and the carbon layer, thereby improving measurement sensitivity and reproducibility.

Invention effect

The present invention can provide an electrochemical analysis chip capable of measuring a plurality of items by one sampling.

Description of drawings

FIG. 1 is a schematic configuration diagram showing an example of an electrochemical measurement device.

Fig. 2 is a plan view showing an embodiment of an electrochemical analysis chip.

Fig. 3 is an isolated perspective view of the electrochemical analysis chip.

Fig. 4 is a side central longitudinal sectional view of the electrochemical analysis chip.

FIG. 5 is a schematic plan view showing an electrode chip.

FIG. 6 is a schematic cross-sectional view corresponding to the position AA of FIG. 5 .

FIG. 7 is a graph showing current-potential curves obtained using electrode chips mounted in the embodiment and a comparison chip.

8 is a photomicrograph of the electrode chip after measurement and the working electrode of the comparison chip taken from the substrate side. FIG. 8(A) shows an embodiment (electrode chip), and FIG. 8(B) shows a comparative example (comparison chip).

9 is a schematic cross-sectional view showing another configuration of the electrode chip.

Fig. 10 is a plan view showing another embodiment of the electrochemical analysis chip.

Fig. 11 is a plan view showing still another embodiment of an electrochemical analysis chip.

Fig. 12 is an isolated perspective view of the electrochemical analysis chip.

Detailed ways

Embodiments of the electrochemical analysis chip will be described based on the drawings. FIG. 1 is a schematic configuration diagram showing an example of an electrochemical measurement device. Fig. 2 is a plan view showing an embodiment of an electrochemical analysis chip. Fig. 3 is an isolated perspective view of the electrochemical analysis chip. Fig. 4 is a side central longitudinal sectional view of the electrochemical analysis chip. It should be noted that, in FIG. 2 , illustration of the lid substrate 213 is omitted. In addition, in FIG. 4, the thickness of each member is enlarged and shown in figure for convenience.

As shown in FIG. 1 , an electrochemical measurement device 1 includes an electrochemical analysis chip 2, a potentiostat 3 connected to the electrochemical analysis chip 2, an operation unit 4 connected to the potentiostat 3, a display unit 5, a power supply unit 6 and External output section 7. In this embodiment, the electrochemical analysis chip 2 is a disposable electrochemical analysis chip.

As shown in FIGS. 2 to 4 , the electrochemical analysis chip 2 has: an insulating base material 21; a plurality of sensor parts 22, which are provided on the base material 21; Section 22 guides the sample liquid. In this embodiment, three sensor units 22 are provided, but in the electrochemical analysis chip of the present invention, the number of sensor units may be two or four or more.

The base material 21 is configured such that a lid substrate 213 is disposed on a base substrate 211 with a flow channel substrate 212 interposed therebetween. The base substrate 211 , the channel substrate 212 , and the lid substrate 213 are composed of substantially quadrangular insulating substrates.

A notch 214 and a groove 215 are formed on the flow path substrate 212. The notch 214 can be inserted into the electrode chip 24 having the sensor portion 22. The groove 215 is used to form the sample liquid supply port 231 and the sample liquid flow path 232 . In this embodiment, three notch portions 214 are formed.

The notch 214 opens on the first side surface 212 a of the flow path substrate 212 and is formed with a width slightly larger than that of the electrode chip 24 . The notch portion 214 is covered by the base substrate 211 and the lid substrate 213 , thereby forming the electrode chip arrangement portion 216 .

The groove 215 is formed on one surface of the flow path substrate 212, extends from the second side surface 212b opposite to the first side surface 212a of the flow path substrate 212 toward the first side surface 212a, branches into three in the middle, and connects with the three notches 214. connected. The groove 215 is covered by the cover substrate 213, thereby forming the flow path portion 23 having a sample liquid supply port 231 on the outer surface of the base material 21 (the second side of the flow path substrate 212) and a sample liquid flow path 232. The side surface 212 b ) is open, and the sample liquid channel 232 guides the same sample liquid from the sample liquid supply port 231 to the plurality of sensor units 22 .

The material of the insulating substrate constituting the base substrate 211, the channel substrate 212, and the cover substrate 213 is not particularly limited, and examples thereof include glass, quartz glass, polyimide (PI: polyimide), polyethylene terephthalate (PET: polyethyleneterephthalate), polycarbonate (PC: polycarbonate), polyethylene (PE: polyethylene), polypropylene (PP: polypropylene), polystyrene (PS: polystyrene), polyvinyl chloride (PVC: polyvinylchloride), polyethylene Formaldehyde (POM: polyoxymethylene), ABS resin (ABS (acrylonitrile-butadiene-styrene), acrylonitrile-butadiene-styrene), polymethyl methacrylate resin (PMMA: polymethyl methacrylate), etc. In addition, the shape, thickness, and size of the insulating substrate are not particularly limited.

In addition, the size of the sample liquid supply port 231 and the sample liquid channel 232 may be such that the sample liquid can be introduced from the sample liquid supply port 231 to the sample liquid channel 232 by capillary action, and guided to the sensor unit 22 . In addition, a hydrophilic treatment layer for improving wettability may be formed on the inner wall surface of the sample liquid channel 232 (the inner wall surface of the groove 215 and the bonding surface of the lid substrate 213 with the channel substrate 212 ).

As shown in FIGS. 3 and 4 , the base material 21 of the electrochemical analysis chip 2 is formed by laminating and integrating a base substrate 211 , a channel substrate 212 , and a lid substrate 213 in this order. For the bonding of the base substrate 211 and the flow channel substrate 212 and the bonding of the flow channel substrate 212 and the lid substrate 213 , for example, an adhesive or heat welding can be used.

The electrode chip 24 having the sensor part 22 is mounted on the electrode chip arrangement part 216 of the base material 21 . The electrode chip 24 includes a flat insulating substrate 241 , and a working electrode 242 , a counter electrode 243 , and a reference electrode 244 are provided on the substrate 241 to be insulated from each other. The substrate 241 has a substantially rectangular shape in plan view. The working electrode 242 , the counter electrode 243 , and the reference electrode 244 are provided so as to extend from the vicinity of one end in the longitudinal direction of the substrate 241 to the vicinity of the other end. Halfway in the longitudinal direction of the working electrode 242 , the counter electrode 243 , and the reference electrode 244 are covered with an insulating layer 245 formed on the substrate 241 . One end side of the working electrode 242 , the counter electrode 243 , and the reference electrode 244 constitutes the sensor unit 22 .

One end side of the electrode chip 24 is inserted into the electrode chip arrangement part 216 of the substrate 21, whereby the sensor part 22 (one end side of the working electrode 242, the counter electrode 243, and the reference electrode 244) is arranged on the electrode chip arrangement part 216. internal. A small gap is formed between the inner wall of the electrode chip arrangement part 216 and the electrode chip 24, and this gap is such that the sample solution introduced into the flow path part 23 by capillary phenomenon flows toward the opening side of the electrode chip arrangement part 216 (the second electrode chip arrangement part 216). One side 212a side) degree of penetration.

It should be noted that the size of the gap between the inner wall of the electrode chip arrangement part 216 and the electrode chip 24 can be as long as the sample solution permeates from the sample solution channel 232 toward the opening of the electrode chip arrangement part 216 by capillary phenomenon. Yes, there is no particular limitation. In addition, on the inner wall surface of the electrode chip arrangement part 216 (the inner wall surface of the notch part 214, the bonding surface of the base substrate 211 and the flow path substrate 212, and the bonding surface of the lid substrate 213 and the flow path substrate 212) Forms a hydrophilic treatment layer that improves wettability.

The other end side of the working electrode 242, the counter electrode 243, and the reference electrode 244 positioned at the other end side of the electrode chip 24 are disposed outside the substrate 21, and are connected to the potentiostat 3 via the connector 8 and the cable 9 (refer to FIG. 2 ). (Refer to Figure 1) Electrical connection. The electrode chip 24 is detachably attached to the connector 8 .

When the sample solution is supplied to the sample solution supply port 231 of the electrochemical analysis chip 2, the sample solution flows toward the three electrode chip arrangement parts 216 (notches 214) in the sample solution flow channel 232 to each electrode by capillary action. The chip configuration unit 216 is introduced. The sample solution introduced into the electrode chip arrangement part 216 flows toward the opening side of the electrode chip arrangement part 216 (first side surface 212a side) in the gap between the electrode chip arrangement part 216 and the electrode chip 24 by capillary phenomenon, and contacts with the electrode chip 24. The sensor part 22 is in contact.

As shown in FIGS. 1 to 4 , the electrochemical analysis chip 2 of this embodiment includes: a sensor unit 22 having a plurality of electrodes 242, 243, 244 and provided on an insulating substrate 21; The sample liquid is guided to the sensor unit 22 on the substrate 21 . A plurality of sensor parts 22 are provided on the base material 21, and the flow path part 23 is equipped with: a sample liquid supply port 231, which is opened on the outer surface of the base material 21; Guided to the plurality of sensor units 22 .

According to the electrochemical analysis chip 2, the same sample liquid can be guided from the sample liquid supply port 231 to the plurality of sensor parts 22 through the sample liquid flow path 232, and therefore, the same sample liquid can be brought into contact with the plurality of sensor parts 22 through one sampling operation. . Thereby, even a trace amount of sample liquid can perform measurement of a plurality of items by one sampling operation.

In the electrochemical analysis chip 2 , the channel section 23 includes a plurality of sample solution channel 232 connected to one sample solution supply port 231 . As a result, the sample liquid can be introduced into the plurality of sensor units 22 only by bringing the sample liquid into contact with one sample liquid supply port 231 , so that the sampling operation is easy and the time required for the sampling operation can be shortened.

In the electrochemical analysis chip 2 , the sensor section 22 is provided on the electrode chip 24 attachable to the base material 21 . The base material 21 is provided with an electrode chip arrangement part 216 which opens on the outer surface of the base material 21 into which the electrode chip 24 is inserted. The sample solution channel 232 is connected to the electrode chip arrangement part 216, and a gap is provided between the inner wall of the electrode chip arrangement part 216 and the electrode chip 24, and the gap allows the sample solution to be arranged from the sample solution channel 232 toward the electrode chip by capillary action. The opening of portion 216 is soaked. Accordingly, it is possible to cope with many measurement items by replacing the electrode chip 24 according to the measurement items, and thus the versatility of the electrochemical analysis chip 2 is improved.

Next, electrodes of the electrode chip 24 having the sensor portion 22 will be described with reference to FIGS. 5 and 6 as well. At least one surface of the substrate 241 of the electrode chip 24 is formed of a flat insulating material. The substrate 241 is, for example, a polyethylene terephthalate film, a polyimide film, a glass substrate, a glass epoxy (glass epoxy: glass epoxy) substrate, or the like. However, the material of the substrate 241 is not limited to these, and may be ceramics, quartz glass, or the like.

In the electrode chip 24, the working electrode 242, the counter electrode 243, and the reference electrode 244 respectively have a metal layer 251 formed on the substrate 241, a carbon layer 252 formed on the substrate 241 so as to cover the metal layer 251, and a carbon layer 252 formed on the substrate 241. The lower adhesive layer 253 between the substrate 241 and the metal layer 251 and the upper adhesive layer 254 are formed between the upper surface of the metal layer 251 and the carbon layer 252 . A silver silver chloride layer 255 is formed on the upper surface of the carbon layer 252 on one end side of the reference electrode 244 .

Lower adhesive layer 253 is a thin film for preventing peeling between substrate 241 and metal layer 251 , and is formed of silicon, for example. As the material of the lower adhesive layer 253, as long as it is a material with good adhesion between the substrate 241 and the metal layer 251, in addition to silicon, for example, chromium and titanium (a metal covalently bonded to carbon) can also be used. Wait.

The metal layer 251 is made of a material having a lower resistivity than the carbon layer 252 , and is formed on the lower adhesive layer 253 . The metal layer 251 is a layer for reducing the resistance between one end and the other end of each of the working electrode 242 , the counter electrode 243 , and the reference electrode 244 . As the material of the metal layer 251 , for example, silver, ruthenium, tantalum, titanium, copper, aluminum, platinum, niobium, zirconium, alloys of these elements, alloys of these elements and carbon, or the like can be used.

The upper adhesive layer 254 is formed on the upper surface of the metal layer 251 , is a thin film that prevents the upper surface of the metal layer 251 from being peeled off from the carbon layer 252 , and is formed of silicon.

Carbon layer 252 is formed on substrate 241 to cover lower adhesive layer 253 , metal layer 251 , and upper adhesive layer 254 . The carbon layer 252 is formed of, for example, amorphous carbon or diamond-like carbon (DLC: diamond-like carbon). In addition, the carbon layer 252 is formed in a contour surrounding the lower adhesive layer 253 , the metal layer 251 , and the upper adhesive layer 254 in plan view, and the lower surface peripheral portion of the carbon layer 252 is in contact with the substrate 241 . The lower adhesive layer 253 , the metal layer 251 and the upper adhesive layer 254 are isolated from the surrounding atmosphere due to being surrounded by the substrate 241 and the carbon layer 252 .

Carbon is suitable for use in the carbon layer 252 that protects the metal layer 251 because it has the following characteristics. (1) It has excellent stability even in a vacuum of 3000°C (in the air of 500°C); (2) It is not easily corroded by chemicals; (3) It is impermeable to gases and solutions; (4) It has excellent hardness , strength; (5) has excellent electrical conductivity; (6) has resistance to wetting of metal salts, etc.; (7) has good blood and tissue compatibility; (8) has isotropic physical and chemical properties .

As a method of manufacturing lower adhesive layer 253 , metal layer 251 , upper adhesive layer 254 , and carbon layer 252 , a vapor deposition method is preferable from the viewpoint of being able to control the shape and film thickness of each layer with high precision. Here, as the vapor deposition method, so-called physical vapor deposition (PVD: physical vapor deposition) such as vacuum vapor deposition, ion plating, and sputtering, and so-called chemical vapor deposition (CVD: chemical vapor deposition) can be used. However, the manufacturing method of each layer is not limited to the vapor deposition method, but printing methods such as screen printing method and inkjet printing method may also be used.

In this embodiment, the electrodes 242, 243, and 244 include a metal layer 251 formed on an insulating substrate 241, a carbon layer 252 formed on the substrate 241 so as to cover the metal layer 251, and a carbon layer 252 formed between the substrate 241 and the metal layer. A lower adhesive layer 253 between layers 251 . Since the electrodes 242, 243, and 244 have the metal layer 251, the electrical resistance can be reduced, and the measurement sensitivity can be improved. In addition, by covering the metal layer 251 with the carbon layer 252, oxidation and reduction of the metal layer 251 can be prevented, and measurement sensitivity and reproducibility can be improved. Furthermore, by providing an upper adhesive layer 254 made of silicon between the upper surface of the metal layer 251 and the carbon layer 252, the adhesion between the metal layer 251 and the carbon layer 252 is improved, and since silicon has a higher resistivity than metal, Generation of hydrogen on the upper surface of the metal layer 251 during measurement can be suppressed. Thereby, peeling of the substrate 241 and the metal layer 251 is prevented, and measurement sensitivity and reproducibility can be improved.

In addition, since the electrodes 242, 243, and 244 include the lower adhesive layer 253 formed between the substrate 241 and the metal layer 251, it is possible to prevent the decrease in the adhesion between the substrate 241 and the metal layer 251 during measurement, and to improve the measurement performance. Sensitivity and reproducibility.

In addition, the metal layer 251, the carbon layer 252, and the adhesive layers 253 and 254 are layers formed by a vapor deposition method. The metal layer 251 and the adhesive layers 253 and 254 are formed in the same shape in a plan view, and the carbon layer 252 is formed in a plan view. Observe the outline formed to surround the metal layer 251 and the adhesive layers 253 , 254 . By forming each layer 251, 252, 253, 254 by vapor deposition, the shape and film thickness of each layer 251, 252, 253, 254 can be controlled with high precision, and the overall improvement can be achieved for each of the electrodes 242, 243, 244. resistance stability.

In addition, the lower adhesive layer 253 is formed of silicon. Since silicon has good adhesion to glass and metal, it can enhance the adhesion between metal layer 251 and substrate 241 . In addition, the upper adhesive layer 254 is also formed of silicon. Since silicon has good adhesion to metals and carbon, the adhesion between the metal layer 251 and the carbon layer 252 can be enhanced.

Since the sensor unit 22 includes a working electrode 242 , a reference electrode 244 , and a counter electrode 243 , it can be applied to three-electrode electrochemical measurements. In addition, the working electrode 242, the reference electrode 244, and the counter electrode 243 can reduce the resistance, prevent the oxidation and reduction of the metal layer 251, and prevent the peeling of the metal layer 251, so the measurement sensitivity and reproducibility can be improved.

It should be noted that the sensor unit 22 may be a sensor unit including two electrodes used in electrochemical measurement of a two-electrode system using the working electrode 242 and the reference electrode 244 . In addition, if both the working electrode and the reference electrode are composed of electrodes having a metal layer, a carbon layer, and an adhesive layer, the resistance of the working electrode and the reference electrode can be reduced, and the metal layer can be prevented from being damaged. Oxidation reduction and can prevent the peeling of the metal layer, therefore, can improve the measurement sensitivity and reproducibility.

In addition, the working electrode 242, the counter electrode 243, and the reference electrode 244 of the sensor unit 22 are not limited to the above-mentioned structure, and may be a single-layer structure of a metal material such as silver, platinum, gold, aluminum, palladium, or a conductive material such as carbon, for example. A single-layer structure, or a laminated structure in which a plurality of these materials are laminated. In addition, the lower adhesive layer 253 may not be provided in the electrodes 242 , 243 , and 244 .

As shown in FIG. 1 , the potentiostat 3 is configured to control the potential of the working electrode 242 of the electrode chip 24 with respect to the reference electrode 244 to be constant, and can measure the voltage flowing between the working electrode 242 and the counter electrode 243. current. As a schematic configuration, the potentiostat 3 includes an arithmetic control unit 31 , a voltage application unit 32 , and a current detection unit 33 .

The calculation control unit 31 has a function of performing predetermined calculation processing using measured values obtained by electrochemical measurement, and transmitting a signal required by the voltage applying unit 32 or displaying a signal on the display unit based on an instruction from the user input through the operation unit 4 . 5Display information such as measurement results. The arithmetic control unit 31 is realized, for example, by a microcomputer executing a predetermined program.

The voltage applying unit 32 is configured to apply a voltage of a desired waveform between the working electrode 242 and the counter electrode 243 of the counter electrode chip 24 when receiving the measurement start signal from the calculation control unit 31, so that the working electrode 242 and the counter electrode 243 are connected to each other. Control is performed so that the potential between the electrodes 244 becomes a desired potential.

The current detection unit 33 is configured to detect the magnitude of the current flowing between the working electrode 242 and the counter electrode 243 of the electrode chip 24 . A signal related to the magnitude of the current detected by the current detection unit 33 is taken into the arithmetic control unit 31 .

The arithmetic control unit 31 is configured to calculate the concentration of a specific component in the sample solution based on the signal received from the current detection unit 33 using, for example, a calibration curve prepared in advance, and display the measurement result on the display unit 5 .

In the electrochemical measurement device 1 , the operation unit 4 is an input device for the user to perform operations such as turning on/off a power supply, starting a measurement, and changing information displayed on the display unit 5 . The display unit 5 is realized by, for example, a liquid crystal display. It should be noted that the display unit 5 may be configured with a touch panel, and the display unit 5 may also function as the operation unit 4 . The power supply unit 6 can be realized by, for example, a dry cell, a storage battery, or the like. Necessary electric power is supplied to the potentiostat 3 and the display unit 5 through the power supply unit 6 .

In addition, an external output unit 7 may be connected to the potentiostat 3 so that information can be output to external devices such as a personal computer through a wired communication means such as a USB (universal serial bus) terminal or a wireless communication means. . In this case, the arithmetic control unit 31 is configured to output measurement data and the like to an external device through the external output unit 7 .

It should be noted that the operation unit 4 , the display unit 5 , the power supply unit 6 , and the external output unit 7 may be realized by, for example, mobile computers such as notebook computers and tablet computers. Furthermore, if a small potentiostat (for example, a small potentiostat "miniSTAT100" (manufactured by BioDevice Technology)) is used as the potentiostat 3, the electrochemical measuring device 1 can be configured to be portable. This enables on-site measurement of a sample liquid using the electrochemical measurement device 1 .

The electrochemical measurement using the electrochemical measurement device 1 is performed in a state where the sample liquid is in contact with the sensor unit 22 of the electrochemical analysis chip 2 . That is, the measurement is performed in a state where the sample liquid is brought into contact with the sample liquid supply port 231 of the electrochemical analysis chip 2 to introduce the sample liquid into the sample liquid channel 232 and the electrode chip arrangement part 216 .

Next, a fabrication example of the electrode chip 24 will be described. On a glass substrate with a thickness of about 2500 nm (2.5 μm) as the substrate 241, a silicon layer with a thickness of about 20 nm is formed as the lower part by sputtering using a metal mask having an opening pattern corresponding to the region where the lower adhesive layer is formed. Adhesive layer 253 . It should be noted that the film thickness of the lower adhesive layer 253 formed of silicon is not particularly limited.

Using a metal mask having the same opening pattern as the opening pattern corresponding to the lower adhesive layer forming region of the metal mask, a silver layer with a thickness of about 150 nm is formed as a metal layer on the lower adhesive layer 253 by sputtering. Layer 251.

Thereafter, a silicon layer having a thickness of about 20 nm is formed as an upper adhesive layer 254 on the metal layer 251 by sputtering using a metal mask having the same opening pattern as that corresponding to the lower adhesive layer forming region. It should be noted that the film thickness of the upper adhesive layer 254 formed of silicon is not particularly limited.

Here, after carrying the substrate 241 into the chamber of the sputtering apparatus, the lower adhesive layer 253, the metal layer 251, and the upper adhesive layer 254 are formed on the substrate without being carried out from the chamber using the same metal mask. 241 on. Accordingly, the time required for film formation of the lower adhesive layer 253 , the metal layer 251 , and the upper adhesive layer 254 can be shortened, and adhesion of foreign matter between the respective layers can be prevented. In addition, the metal layer 251 and the adhesive layers 253 and 254 are formed in the same shape in plan view.

The line width (the dimension in the width direction perpendicular to the longitudinal direction) of the lower adhesive layer 253 , the metal layer 251 , and the upper adhesive layer 254 is about 0.6 mm.

Carbon layer 252 with a thickness of about 1000 nm is formed by sputtering so as to cover lower adhesive layer 253 , metal layer 251 , and upper adhesive layer 254 using a metal mask having an opening pattern surrounding the region where the lower adhesive layer is formed. . The line width of the carbon layer 252 is about 1 mm. Thus, working electrode 242 , counter electrode 243 , and reference electrode 244 each having lower adhesive layer 253 , metal layer 251 , upper adhesive layer 254 , and carbon layer 252 are formed.

In this way, the lower adhesive layer 253, the metal layer 251, the upper adhesive layer 254, and the carbon layer 252 are formed by vapor deposition (here, sputtering) using a metal mask having an opening pattern. After film formation of each layer, patterning by etching or lift-off is unnecessary, and manufacturing cost can be reduced.

On the upper surface of the carbon layer 252 on the one end side of the reference electrode 244 , a silver layer with a thickness of about 100 nm was formed by a film-forming method and subjected to chlorination treatment to form a silver-silver chloride layer 255 . In this way, the electrode chips 24 are fabricated.

In each electrode 242, 243, 244 of the electrode chip 24, the side surface of the metal layer 251 is in contact with the carbon layer 252, although it can be considered that during the electrochemical measurement, due to the water soaked in the carbon layer 252, the side surface of the metal layer 251 Hydrogen is generated, but since the metal layer 251 is very thin at 150 nm in thickness, it is considered that even if hydrogen is generated on the side surface of the metal layer 251, the amount of hydrogen is extremely small and has little influence on the measurement.

The film thickness of the metal layer 251 is not particularly limited, but is preferably not less than 50 nm and not more than 1000 nm. This is because, within this range, the overall resistance value of the electrodes 242 , 243 , and 244 can be reduced while suppressing the amount of hydrogen generated on the side surfaces of the metal layer 251 to a small amount. In addition, when the film thickness of the metal layer 251 is thinner than 50 nm, the electrodes 242, 243, and 244 become high resistance, and measurement sensitivity falls. In addition, when the film thickness of the metal layer 251 is thicker than 1000 nm, the influence of hydrogen generated on the side surface of the metal layer 251 on the measurement becomes greater. In particular, when the metal layer 251 is formed by a vapor deposition method (such as a sputtering method), when the film thickness of the metal layer 251 is thicker than 1000 nm, the time required for the film formation of the metal layer 251 becomes longer, and the production Reduced efficiency.

It should be noted that, after forming a plurality of electrode chips 24 in a region where a plurality of electrode chips 24 are provided on one substrate 241 at the same time, each electrode chip 24 is singulated, thereby reducing the manufacturing cost.

Next, a measurement example using the electrode chip 24 will be described. A solution obtained by diluting a 100 ppm lead standard solution (Wako Pure Chemical Industries, Ltd.) to 1000 ppb (=1 ppm) with distilled water was used as a sample. As a comparative example of electrode chip 24 , an electrode chip in which metal layer 251 and carbon layer 252 were formed on substrate 241 without forming adhesive layers 253 and 254 was produced as a comparison chip.

A small potentiostat “miniSTAT100” (manufactured by BioDevice Technology) was used as the potentiostat 3 . Electrochemical measurement was performed by differential pulse voltammetry (DPV: differential pulse voltammetry). The measurement by DPV was performed with the potential of the working electrode changed from −1500 mV to 300 mV, with a potential increase of 0.004 V, a pulse amplitude of 0.05 V, a pulse duration of 0.2 seconds, and a scan rate of 0.02 V/s. Measurements were performed by dropping about 20 μL of the above-mentioned sample on the electrode chip 24 and the comparison chip. The obtained current-potential curve is shown in FIG. 7 . In FIG. 7 , the vertical axis represents current, and the horizontal axis represents potential.

As can be seen from FIG. 7 , in the measurement (see solid line A) using the electrode chip 24 of the embodiment, a good Pb peak was obtained. On the other hand, it was confirmed that in the measurement using the comparison chip (see dotted line B), the Pb peak was smaller and the Ag peak was larger than in the embodiment.

Fig. 8 is a photomicrograph of the electrode chip 24 after measurement and the working electrode 242 of the comparison chip taken from the substrate 241 side, (A) of Fig. 8 shows an embodiment (electrode chip 24), and (B) of Fig. 8 shows a comparative example ( compare chips).

As can be seen from FIG. 8 , peeling off of the metal layer 251 was observed in (B) the comparative chip of FIG. 8 , but peeling off of the metal layer and the lower adhesive layer 253 was not observed in the electrode chip of the embodiment (A) in FIG. 8 . .

In this manner, it was confirmed that providing the lower adhesive layer 253 between the substrate 241 and the metal layer 251 prevents the substrate 241 from being peeled off from the metal layer 251 , thereby improving measurement sensitivity and reproducibility.

In the electrode chip 24 , as shown in FIG. 9 , an upper adhesive layer 254 made of silicon may also be formed to cover the side surfaces of the metal layer 251 . Such an upper adhesive layer 254 can be formed by a vapor deposition method (for example, a sputtering method). Thereby, the area where the metal layer 251 contacts the carbon layer 252 disappears, even if water penetrates to the carbon layer 252, the generation of hydrogen on the surface of the metal layer 251 during measurement can be prevented, and the contact between the metal layer 251 and the carbon layer 252 can be improved. of tightness. Thereby, peeling of the carbon layer 252 can be prevented more reliably.

Next, another embodiment of the electrochemical analysis chip will be described with reference to FIG. 10 . Fig. 10 is a plan view showing another embodiment of the electrochemical analysis chip. It should be noted that, in FIG. 10 , illustration of the lid substrate 213 is omitted.

In the electrochemical analysis chip 2A of this embodiment, the channel section 23 includes a sample solution supply port 231 and a sample solution channel 232 for each of the plurality of sensor sections 22 . That is, three grooves 215 formed on one surface of the flow path substrate 212A are provided so as to be separated from each other. In addition, three sample liquid supply ports 231 constituted by one end portions of the three grooves 215 are disposed close to each other on the outer surface of the substrate 21A (the second side surface 212b of the flow channel substrate 212A).

According to the electrochemical analysis chip 2A, by providing the sample liquid supply port 231 and the sample liquid channel 232 for each sensor portion 22 , the sample liquid can be reliably introduced into each sensor portion 22 . In addition, by arranging the sample liquid supply ports 231 provided for each sensor unit 22 close to each other on the outer surface of the substrate 21A, the sample liquid can be reliably brought into contact with these sample liquid supply ports 231 in one sampling operation, and the sampling rate can be improved. Processing reliability.

Next, still another embodiment of the electrochemical analysis chip will be described with reference to FIGS. 11 and 12 . Fig. 11 is a plan view showing still another embodiment of an electrochemical analysis chip. Fig. 12 is an isolated perspective view of the electrochemical analysis chip. It should be noted that, in FIG. 11 , illustration of the lid substrate 213B is omitted.

In the electrochemical analysis chip 2B of this embodiment, the substrate 21B is formed by stacking a base substrate 211B on which the sensor portion 22 is formed, a flow path substrate 212B on which the flow path portion 23 is formed, and a lid substrate 213B covering the flow path substrate 212B. constitute.

Each sensor unit 22 is formed on one end of a working electrode 242, a counter electrode 243, and a reference electrode 244, which are electrodes provided in the electrochemical analysis chip 2 of the above-mentioned embodiment. The electrodes 242, 243, and 244 of the chip 24 have the same configuration. The other ends of the electrodes 242 , 243 , and 244 are disposed on the connector connection portion 217 protruding from one side of the base substrate 211B.

In place of the notch 214 provided in the electrochemical analysis chip 2 of the above-described embodiment, a sample liquid storage portion 218 composed of a through hole is formed on the flow channel substrate 212B (see FIGS. 2 and 3 , etc.). The sample liquid storage portion 218 is formed at a position surrounding the sensor portion 22 in a state where the base substrate 211B and the channel substrate 212B are superposed.

Moreover, the flow path part 23 for forming the sample liquid supply port 231 and the sample liquid flow path 232 is formed in the flow path board|substrate 212B similarly to the electrochemical analysis chip 2 of the said embodiment. The end portion of the sample liquid channel 232 on the side opposite to the sample liquid supply port 231 is connected to the sample liquid container 218 .

An air hole 219 is formed at a position overlapping the sample liquid container 218 in plan view on the lid substrate 213B bonded to the flow path substrate 212B.

When the sample liquid is supplied to the sample liquid supply port 231 of the electrochemical analysis chip 2B by a sampling operation, the sample liquid flows toward the three sample liquid storage parts 218 in the sample liquid channel 232 by capillary phenomenon, and is accommodated in each sample liquid. The part 218 is introduced to be in contact with each sensor part 22. In this way, the electrochemical analysis chip 2B can bring the same sample liquid into contact with a plurality of sensor units 22 in one sampling operation.

According to such a configuration, the size reduction of the electrochemical analysis chip 2B can be achieved by integrating the plurality of sensor units 22 with the base substrate 211B. The configuration in which the sensor unit 22 is integrated with the base substrate 211B is also applicable to the configuration in which the sample solution supply port 231 and the sample solution channel 232 are provided for each sensor unit 22 (see FIG. 10 ).

The present invention is not limited to the aforementioned embodiments, and can be embodied in various forms. For example, the electrochemical analysis chip may have a configuration that does not include the counter electrode 243 but includes the working electrode 242 and the reference electrode 244 as electrodes, and is applicable to electrochemical measurement using a two-electrode method.

In addition, the location where the sample solution supply port is arranged is not limited to the side surface of the substrate constituting the electrochemical analysis chip, and the sample solution supply port may also be arranged on a plane of the substrate (for example, the side of the base substrate 211 opposite to the channel substrate 212). side of the cover substrate 213 or the surface of the cover substrate 213 opposite to the flow path substrate 212).

In addition, the electrochemical analysis chip of the present invention can also be applied to linear potential scanning method (LSV: linearsweep voltammetry), chronoamperometry (CA: chronoamperometry), cyclic voltammetry (CV: cyclicvoltammetry), short waveform voltammetry (SWV ) and other methods, not limited to differential pulse voltammetry (DPV).

Explanation of reference signs

2, 2A, 2B: electrochemical analysis chip;

21, 21A, 21B: substrate;

22: Sensor Department;

23: Flow path department;

24: electrode chip;

211, 211A, 211B: base substrate;

212, 212A, 212B: flow path substrates;

212b: second side (an example of the outer surface of the substrate);

213, 213B: cover substrate;

216: Electrode Chip Configuration Department;

231: sample liquid supply port;

232: sample liquid flow path;

242: working electrode (an example of an electrode);

243: counter electrode (an example of an electrode);

244: Reference electrode (an example of an electrode).

Claims (6)

1. An electrochemical analysis chip, equipped with a sensor part and a flow path part, the sensor part has a plurality of electrodes and is provided on an insulating substrate, and the flow path part is provided on the substrate and extends to the sensor part guides the sample solution, the electrochemical analysis chip, A plurality of the sensor parts are provided on the base material, The channel unit includes a sample liquid supply port opening on the outer surface of the substrate, and a sample liquid flow channel that guides the same sample liquid from the sample liquid supply port to the plurality of sensor units. 2. The electrochemical analysis chip according to claim 1, wherein, The flow path section includes a plurality of sample liquid flow paths connected to one sample liquid supply port. 3. The electrochemical analysis chip according to claim 1, wherein, The channel section includes the sample solution supply port and the sample solution channel for each of the plurality of sensor sections, A plurality of the sample liquid supply ports are disposed close to each other on the outer surface of the substrate. 4. The electrochemical analysis chip according to any one of claims 1 to 3, wherein, The sensor part is provided on an electrode chip attachable to the substrate, The base material has an electrode chip disposition portion, and the electrode chip disposition portion opens on an outer surface of the base material for insertion of the electrode chip, The sample liquid flow path is connected to the electrode chip arrangement part, and a gap is provided between the inner wall of the electrode chip arrangement part and the electrode chip, and the gap allows the sample liquid to flow from the sample liquid through capillary phenomenon. The flow path permeates toward the opening of the electrode chip placement portion. 5. The electrochemical analysis chip according to any one of claims 1 to 3, wherein, The base material is configured by laminating a base substrate on which the sensor portion is formed, a flow path substrate forming the flow path portion, and a lid substrate covering the flow path substrate. 6. The electrochemical analysis chip according to any one of claims 1 to 5, wherein, The sensor unit has a working electrode and a reference electrode or a working electrode, a reference electrode, and a counter electrode as the electrodes, The electrode includes a metal layer formed on an insulating substrate, a carbon layer formed on the substrate so as to cover the metal layer, and a carbon layer formed between an upper surface of the metal layer and the carbon layer. the upper adhesive layer, The upper adhesive layer is formed of silicon.

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