Graphene three-electrode coplanar standard electrode and application thereof

Abstract

This invention provides a graphene three-electrode coplanar standard electrode and its application. Specifically, three coplanar electrodes are fixedly disposed on an electrode substrate, which are, from left to right, a first electrode, a second electrode, and a third electrode. The first electrode includes a first pin (1), a first guide portion (4), and a first detection layer (7); the second electrode includes a second pin (2) and a second guide portion (5); and the third electrode includes a third pin (3), a third guide portion (6), and a second detection layer (8). An electrode modification hole (9) is formed by drilling a hole in the electrode substrate and is placed directly above the second electrode. A through hole (10) is provided in the middle of the second guide portion (5). A back electrode is disposed on the back side of the electrode substrate, specifically including a back pin (11), a back guide portion (12), and an electrode modification ring (13). The back guide portion (12) is provided with a through hole (10), and the electrode modification hole (9) is provided inside the inner ring of the electrode modification ring (13).

Description

Technical Field

[0001] This invention belongs to the field of electrochemical interdigitated electrodes and relates to a graphene three-electrode coplanar standard electrode and its application. Background Technology

[0002] In recent years, with the rapid development of Industry 4.0 and the Internet of Things, emerging industries and other sectors have increasingly demanded sensors. Electrodes, as one of the core components of sensors, have received more and more attention from society. How to improve the detection performance of electrodes is directly related to the technical level of various sensors, which has become a common problem in the electronics and information industry.

[0003] Electrodes are the most important sensitive components of electrochemical sensors. Generally, sensors require two or more electrodes, with three-electrode systems being the most widely used. A three-electrode system consists of a working electrode, a reference electrode, and a counter electrode. However, in traditional three-electrode systems, the three electrodes are not integrated on a single plane; the electrodes are relatively far apart. During electrochemical testing, concentration polarization can easily occur between the working and counter electrodes, affecting the accuracy of the measurement. Furthermore, traditional three-electrode systems are large in size, which is inconvenient for the design and fabrication of miniature sensors, limiting the application of three-electrode systems.

[0004] Patent CN201920553197.X discloses a portable three-electrode structure, which integrates the working electrode, counter electrode and reference electrode on the same plane, greatly reducing the size of the three electrodes and facilitating the design and fabrication of micro sensors.

[0005] However, the working electrode modification layer of the electrodes described above is fixed and cannot be replaced according to the target object being detected, which may lead to waste during use and cause some inconvenience in the specific use of the electrodes. At the same time, modifying the three electrode surfaces with different modification layers on the basis of three coplanar electrodes also brings difficulties to electrode repair and processing, and the electrode processing cost is relatively high.

[0006] In view of the above, the present invention aims to provide a standard electrode in which the working electrode modification layer can be freely replaced according to the needs of the analyte, so as to make the electrode detection performance more flexible while reducing the processing and use costs, making the preparation of the electrode surface modification layer simpler, and the working electrode modification layer, which is the core detection layer, can be freely replaced and used immediately, reducing the processing difficulty and cost of the working electrode detection layer, and bringing broader prospects for electrode applications. Summary of the Invention

[0007] In summary, this invention provides a graphene three-electrode coplanar standard electrode and its application.

[0008] The purpose of this invention is to provide a graphene three-electrode coplanar standard electrode, including an electrode substrate, specifically three coplanar electrodes are fixedly disposed on the electrode substrate, and a first electrode, a second electrode and a third electrode are disposed sequentially from left to right on the front side of the electrode substrate.

[0009] The first electrode includes a first pin (1), a first guide portion (4), and a first detection layer (7); the second electrode includes a second pin (2) and a second guide portion (5); and the third electrode includes a third pin (3), a third guide portion (6), and a second detection layer (8). An electrode modification hole (9) is formed by drilling a hole in the electrode substrate and is placed directly above the second electrode. A through hole (10) is provided at the middle of the second guide portion (5).

[0010] The back electrode is provided on the back side of the electrode substrate, specifically including a back pin (11), a back guide (12) and an electrode trimming ring (13). The back guide (12) is provided with a through hole (10), and the inner ring of the electrode trimming ring (13) is provided with an electrode trimming hole (9). The diameter of the electrode trimming hole (9) is smaller than the inner ring diameter of the electrode trimming ring (13).

[0011] The first electrode is the auxiliary electrode, the second electrode is the working electrode, and the third electrode is the reference electrode.

[0012] Furthermore, the first detection layer (7), the electrode modification hole (9), and the second detection layer (8) are located in the detection section at the upper end of the electrode.

[0013] Furthermore, the first electrode, the second electrode, the third pin (3), the third guide portion (6), and the back electrode area are modified with a metal layer as a substrate, the metal including silver; a modification layer is disposed on the surface of the first detection layer (7), the modification layer including a carbon layer; a modification layer is disposed on the surface of the second detection layer (8), the modification layer including a silver-silver chloride layer.

[0014] Furthermore, the silver layer thickness is 5 μm.

[0015] Furthermore, the carbon layer thickness is 10 μm.

[0016] Furthermore, the thickness of the silver-silver chloride layer is 5 μm.

[0017] Furthermore, an electrode modification layer can be installed at the position of the electrode modification ring (13). The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring (13), and the electrode modification layer completely covers the area of ​​the electrode modification hole (9). The electrode modification layer is connected to the back electrode through contact with the electrode modification ring (13), and thus connected to the second electrode through the through hole (10).

[0018] Furthermore, the electrode modification layer material can be changed arbitrarily according to the detection requirements, and specific materials include graphene.

[0019] Furthermore, an adhesive seal (16) is provided on the back of the electrode, specifically located at the electrode modification ring (13), to fix the electrode modification layer to the back of the electrode.

[0020] As attached Figure 1 and attached Figure 2 The figures shown are front and back views of a standard graphene three-electrode coplanar electrode.

[0021] Furthermore, the electrode surface is coated with ink, and the electrode surface is modified with a single layer of ink or multiple layers of ink to form an electrolytic cell, with the thickness of the single layer of ink being 25-30 μm.

[0022] Furthermore, the front side of the electrode is coated with a first layer of ink (14), covering the electrode area above the first pin (1), the second pin (2) and the third pin (3), excluding the first detection layer (7), the electrode modification hole (9) and the second detection layer (8); a second layer of ink (15) is coated on the surface of the first layer of ink (14), forming a dam structure at the edge of the detection part formed by the first detection layer (7), the electrode modification hole (9) and the second detection layer (8).

[0023] As attached Figure 3 and attached Figure 4 The images shown are schematic diagrams of the front and back sides of the graphene three-electrode coplanar standard electrode covered with ink.

[0024] Another objective of this invention is to provide an application of a graphene three-electrode coplanar standard electrode in biochemical molecular detection.

[0025] As attached Figure 5 The figure shows the electrochemical detection CV curve of the graphene three-electrode coplanar standard electrode prepared in Example 1. As can be seen from the figure, after three cycles of CV testing on the same electrode with graphene as the modified layer, a well-shaped standard bird's-eye diagram is obtained, indicating that the graphene three-electrode coplanar standard electrode prepared in this invention has good electrochemical response characteristics and stability, and can be used for biochemical molecular detection.

[0026] As attached Figure 6 The figure shows the electrochemical detection CV curves of the graphene three-electrode coplanar standard electrode of this invention. As can be seen from the figure, after CV testing of electrodes prepared from different batches with graphene-modified layers, standard bird-shaped patterns with good shapes were obtained, indicating that the graphene three-electrode coplanar standard electrode prepared by this invention has stable electrochemical performance and good anti-interference performance, and can be used for biochemical molecular detection.

[0027] The beneficial effects of this invention are:

[0028] (1) The present invention sets up a working electrode, a reference electrode and an auxiliary electrode on the same plane. A hole is drilled in the core detection area of ​​the working electrode, and the electrode modification layer, which serves as the detection layer, is fixed to the back of the electrode in the form of glue sealing. The electrode modification layer is attached to the electrode modification hole (9) of the modification metal, so that it is connected to the back electrode. It is also connected to the second electrode on the front through the through hole (10) of the back electrode. This avoids modifying different modification layers of the working electrode, reference electrode and auxiliary electrode on the same plane, greatly reduces the difficulty and cost of electrode electroplating, avoids secondary processing, optimizes the function and structural design of the standard electrode, and expands the application field of the electrode.

[0029] (2) By setting the core detection layer of the working electrode as a freely replaceable electrode modification layer, the present invention achieves the purpose of selecting different electrode modification layers according to the characteristics of the target analyte. At the same time, the working electrode modification layer, which is the core detection layer, can be freely replaced and used immediately, making the selection of the working electrode modification layer more diversified and achieving the purpose of detecting a variety of different biochemical molecules by changing the electrode modification layer.

[0030] (3) The present invention integrates a three-electrode system with different functions on the same plane, which greatly reduces and fixes the electrode spacing, reduces detection interference, realizes the miniaturization of the three-electrode coplanar electrode, and greatly improves the electrode sensitivity and accuracy. By designing the pin part to conform to the size of the USB interface, the entire electrode can be tightly connected to the USB interface, thereby enabling connection with conventional electrochemical workstations, which is convenient for use and replacement. Attached Figure Description

[0031] The invention will be further illustrated with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the invention. For those skilled in the art, other drawings can be obtained based on the following drawings without any creative effort.

[0032] Figure 1 This is a front view of a standard graphene three-electrode coplanar electrode;

[0033] Figure 2 This is a schematic diagram of the back side of a standard graphene three-electrode coplanar electrode;

[0034] Figure 3 This is a schematic diagram of the front side of the graphene three-electrode coplanar standard electrode covered with ink;

[0035] Figure 4 This is a schematic diagram of the ink covering the back of a graphene three-electrode coplanar standard electrode;

[0036] Figure 5 The electrochemical detection CV curves of the graphene three-electrode coplanar standard electrode prepared in Example 1 are shown.

[0037] Figure 6 This is the electrochemical detection CV curve of the graphene three-electrode coplanar standard electrode of this invention.

[0038] Legend:

[0039] 1. First pin; 2. Second pin; 3. Third pin; 4. First guide portion; 5. Second guide portion; 6. Third guide portion; 7. First detection layer; 8. Second detection layer; 9. Electrode decoration hole; 10. Through hole; 11. Back pin; 12. Back guide portion; 13. Electrode decoration ring; 14. First layer of ink; 15. Second layer of ink; 16. Encapsulation. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail with reference to the following specific embodiments and the accompanying drawings.

[0041] Example 1

[0042] As attached Figure 1 As shown, this invention provides a graphene three-electrode coplanar standard electrode, comprising a PET plate electrode substrate, with electrode dimensions of 12x35mm and a thickness of 0.35mm. Specifically, three coplanar electrodes are fixedly disposed on the electrode substrate, with a first electrode, a second electrode, and a third electrode arranged sequentially from left to right on the front side of the electrode substrate.

[0043] The first electrode includes a first pin 1, a first guide portion 4, and a first detection layer 7; the second electrode includes a second pin 2 and a second guide portion 5; and the third electrode includes a third pin 3, a third guide portion 6, and a second detection layer 8. An electrode modification hole 9 is formed by drilling a hole in the electrode substrate and positioned directly above the second electrode. The diameter of the electrode modification hole 9 is 2.0 mm. A through hole 10 with a diameter of 0.3 mm is provided at the middle of the second guide portion 5.

[0044] As attached Figure 2 As shown, a back electrode is provided on the back side of the electrode substrate, specifically including a back pin 11, a back guide 12 and an electrode trimming ring 13. The back guide 12 is provided with a through hole 10, and the inner ring of the electrode trimming ring 13 is provided with an electrode trimming hole 9. The diameter of the electrode trimming hole 9 is smaller than the inner ring diameter of the electrode trimming ring 13.

[0045] The first detection layer 7, the electrode modification hole 9, and the second detection layer 8 are located in the detection section at the upper end of the electrode.

[0046] The first electrode, the second electrode, the third pin 3, the third guide portion 6, and the back electrode area are modified with a metal layer as a substrate. The metal includes silver, and the silver layer has a thickness of 5 μm. A modification layer is provided on the surface of the first detection layer 7. The modification layer includes a carbon layer with a thickness of 10 μm. A modification layer is provided on the surface of the second detection layer 8. The modification layer includes a silver-silver chloride layer with a thickness of 5 μm.

[0047] An electrode modification layer can be installed at the electrode modification ring 13 position. The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring 13, and the electrode modification layer completely covers the area of ​​the electrode modification hole 9. The electrode modification layer is connected to the back electrode through contact with the electrode modification ring 13, and thus connected to the second electrode through the through hole 10.

[0048] The electrode modification layer material was selected as hydrophilically treated graphene.

[0049] As attached Figure 4 As shown, an adhesive seal 16 is provided on the back of the electrode, specifically located at the position of the electrode modification ring 13, to fix the graphene modification sheet, which serves as the electrode modification layer, to the back of the electrode.

[0050] As attached Figure 3 As shown, the electrode surface is coated with ink, and the electrode surface is modified with a single layer or multiple layers of ink to form an electrolytic cell. The thickness of the single layer of ink is 25 μm. The front side of the electrode is modified with a first layer of ink 14, which covers the electrode area above the first pin 1, the second pin 2, and the third pin 3, excluding the first detection layer 7, the electrode modification hole 9, and the second detection layer 8. A second layer of ink 15 is modified on the surface of the first layer of ink 14, forming a dam structure at the edge of the detection part formed by the first detection layer 7, the electrode modification hole 9, and the second detection layer 8.

[0051] The first electrode is the auxiliary electrode, the second electrode is the working electrode, and the third electrode is the reference electrode.

[0052] Example 2

[0053] The present invention provides a graphene three-electrode coplanar standard electrode, comprising a BT plate electrode substrate, the electrode dimensions being 12x35mm and the thickness 0.35mm. Specifically, three coplanar electrodes are fixedly disposed on the electrode substrate, with a first electrode, a second electrode, and a third electrode arranged sequentially from left to right on the front side of the electrode substrate.

[0054] The first electrode includes a first pin 1, a first guide portion 4, and a first detection layer 7; the second electrode includes a second pin 2 and a second guide portion 5; and the third electrode includes a third pin 3, a third guide portion 6, and a second detection layer 8. An electrode modification hole 9 is formed by drilling a hole in the electrode substrate and positioned directly above the second electrode. The diameter of the electrode modification hole 9 is 2.0 mm. A through hole 10 with a diameter of 0.3 mm is provided at the middle of the second guide portion 5.

[0055] The back side of the electrode substrate is provided with a back electrode, specifically including a back pin 11, a back guide 12 and an electrode trimming ring 13. The back guide 12 is provided with a through hole 10, and the inner ring of the electrode trimming ring 13 is provided with an electrode trimming hole 9. The diameter of the electrode trimming hole 9 is smaller than the inner ring diameter of the electrode trimming ring 13.

[0056] The first detection layer 7, the electrode modification hole 9, and the second detection layer 8 are located in the detection section at the upper end of the electrode.

[0057] The first electrode, the second electrode, the third pin 3, the third guide portion 6, and the back electrode area are modified with a metal layer as a substrate. The metal includes silver, and the silver layer has a thickness of 5 μm. A modification layer is provided on the surface of the first detection layer 7. The modification layer includes a carbon layer with a thickness of 10 μm. A modification layer is provided on the surface of the second detection layer 8. The modification layer includes a silver-silver chloride layer with a thickness of 5 μm.

[0058] An electrode modification layer can be installed at the electrode modification ring 13 position. The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring 13, and the electrode modification layer completely covers the area of ​​the electrode modification hole 9. The electrode modification layer is connected to the back electrode through contact with the electrode modification ring 13, and thus connected to the second electrode through the through hole 10.

[0059] The electrode modification layer material was chosen to be nanoporous gold.

[0060] An adhesive seal 16 is provided on the back of the electrode, specifically located at the electrode modification ring 13, to fix the nanoporous gold modification sheet, which serves as the electrode modification layer, to the back of the electrode.

[0061] The electrode surface is coated with ink, and the electrode surface is modified with a single layer or multiple layers of ink to form an electrolytic cell. The thickness of the single layer of ink is 30μm. The front side of the electrode is modified with a first layer of ink 14, which covers the electrode area above the first pin 1, the second pin 2 and the third pin 3, excluding the first detection layer 7, the electrode modification hole 9 and the second detection layer 8. A second layer of ink 15 is modified on the surface of the first layer of ink 14, forming a dam structure at the edge of the detection part formed by the first detection layer 7, the electrode modification hole 9 and the second detection layer 8.

[0062] The first electrode is the auxiliary electrode, the second electrode is the working electrode, and the third electrode is the reference electrode.

[0063] Example 3

[0064] The present invention provides a graphene three-electrode coplanar standard electrode, comprising a ceramic plate electrode substrate, the electrode dimensions being 12x35mm and the thickness 0.35mm. Specifically, three coplanar electrodes are fixedly disposed on the electrode substrate, with a first electrode, a second electrode, and a third electrode arranged sequentially from left to right on the front side of the electrode substrate.

[0065] The first electrode includes a first pin 1, a first guide portion 4, and a first detection layer 7; the second electrode includes a second pin 2 and a second guide portion 5; and the third electrode includes a third pin 3, a third guide portion 6, and a second detection layer 8. An electrode modification hole 9 is formed by drilling a hole in the electrode substrate and positioned directly above the second electrode. The diameter of the electrode modification hole 9 is 2.0 mm. A through hole 10 with a diameter of 0.3 mm is provided at the middle of the second guide portion 5.

[0066] The back side of the electrode substrate is provided with a back electrode, specifically including a back pin 11, a back guide 12 and an electrode trimming ring 13. The back guide 12 is provided with a through hole 10, and the inner ring of the electrode trimming ring 13 is provided with an electrode trimming hole 9. The diameter of the electrode trimming hole 9 is smaller than the inner ring diameter of the electrode trimming ring 13.

[0067] The first detection layer 7, the electrode modification hole 9, and the second detection layer 8 are located in the detection section at the upper end of the electrode.

[0068] The first electrode, the second electrode, the third pin 3, the third guide portion 6, and the back electrode area are modified with a metal layer as a substrate. The metal includes silver, and the silver layer has a thickness of 5 μm. A modification layer is provided on the surface of the first detection layer 7. The modification layer includes a carbon layer with a thickness of 10 μm. A modification layer is provided on the surface of the second detection layer 8. The modification layer includes a silver-silver chloride layer with a thickness of 5 μm.

[0069] An electrode modification layer can be installed at the electrode modification ring 13 position. The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring 13, and the electrode modification layer completely covers the area of ​​the electrode modification hole 9. The electrode modification layer is connected to the back electrode through contact with the electrode modification ring 13, and thus connected to the second electrode through the through hole 10.

[0070] The electrode modification layer material was chosen to be pure gold.

[0071] An adhesive seal 16 is provided on the back of the electrode, specifically located at the electrode decoration ring 13, to fix the pure gold decoration sheet, which serves as the electrode decoration layer, to the back of the electrode.

[0072] The electrode surface is coated with ink, and the electrode surface is modified with a single layer or multiple layers of ink to form an electrolytic cell. The thickness of the single layer of ink is 28 μm. The front side of the electrode is modified with a first layer of ink 14, which covers the electrode area above the first pin 1, the second pin 2, and the third pin 3, excluding the first detection layer 7, the electrode modification hole 9, and the second detection layer 8. A second layer of ink 15 is modified on the surface of the first layer of ink 14, forming a dam structure at the edge of the detection part formed by the first detection layer 7, the electrode modification hole 9, and the second detection layer 8.

[0073] The first electrode is the auxiliary electrode, the second electrode is the working electrode, and the third electrode is the reference electrode.

[0074] Example 4

[0075] The graphene three-electrode coplanar standard electrode provided by the present invention includes a glass electrode substrate, the electrode size is 12x35 mm, and the thickness is 0.35 mm. Specifically, three coplanar electrodes are fixedly disposed on the electrode substrate, and the first electrode, the second electrode, and the third electrode are arranged sequentially from left to right on the front side of the electrode substrate.

[0076] The first electrode includes a first pin 1, a first guide portion 4, and a first detection layer 7; the second electrode includes a second pin 2 and a second guide portion 5; and the third electrode includes a third pin 3, a third guide portion 6, and a second detection layer 8. An electrode modification hole 9 is formed by drilling a hole in the electrode substrate and positioned directly above the second electrode. The diameter of the electrode modification hole 9 is 2.0 mm. A through hole 10 with a diameter of 0.3 mm is provided at the middle of the second guide portion 5.

[0077] The back side of the electrode substrate is provided with a back electrode, specifically including a back pin 11, a back guide 12 and an electrode trimming ring 13. The back guide 12 is provided with a through hole 10, and the inner ring of the electrode trimming ring 13 is provided with an electrode trimming hole 9. The diameter of the electrode trimming hole 9 is smaller than the inner ring diameter of the electrode trimming ring 13.

[0078] The first detection layer 7, the electrode modification hole 9, and the second detection layer 8 are located in the detection section at the upper end of the electrode.

[0079] The first electrode, the second electrode, the third pin 3, the third guide portion 6, and the back electrode area are modified with a metal layer as a substrate. The metal includes silver, and the silver layer has a thickness of 5 μm. A modification layer is provided on the surface of the first detection layer 7. The modification layer includes a carbon layer with a thickness of 10 μm. A modification layer is provided on the surface of the second detection layer 8. The modification layer includes a silver-silver chloride layer with a thickness of 5 μm.

[0080] An electrode modification layer can be installed at the electrode modification ring 13 position. The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring 13, and the electrode modification layer completely covers the area of ​​the electrode modification hole 9. The electrode modification layer is connected to the back electrode through contact with the electrode modification ring 13, and thus connected to the second electrode through the through hole 10.

[0081] The electrode modification layer material was chosen to be a metal modified with active enzymes.

[0082] A sealant 16 is provided on the back of the electrode, specifically located at the electrode modification ring 13, to fix the metal sheet modified with active enzyme, which serves as the electrode modification layer, to the back of the electrode.

[0083] The electrode surface is coated with ink, and the electrode surface is modified with a single layer or multiple layers of ink to form an electrolytic cell. The thickness of the single layer of ink is 25 μm. The front side of the electrode is modified with a first layer of ink 14, which covers the electrode area above the first pin 1, the second pin 2 and the third pin 3, excluding the first detection layer 7, the electrode modification hole 9 and the second detection layer 8. A second layer of ink 15 is modified on the surface of the first layer of ink 14, forming a dam structure at the edge of the detection part formed by the first detection layer 7, the electrode modification hole 9 and the second detection layer 8.

[0084] The first electrode is the auxiliary electrode, the second electrode is the working electrode, and the third electrode is the reference electrode.

[0085] Example 5

[0086] Applications of graphene three-electrode coplanar standard electrodes in biochemical molecular detection:

[0087] The three-electrode coplanar standard electrode with graphene as the electrode modification layer prepared in Example 1 was wetted with anhydrous ethanol, and the edges were wiped dry. Before the ethanol on the graphene disk was completely dry, 5 mmol / L potassium ferricyanide solution was added dropwise, ensuring that the solution completely covered the working electrode, auxiliary electrode, and reference electrode. The end pin of the standard electrode was inserted into the USB interface of a portable electrochemical workstation. The starting potential was set to -300 mV, the ending potential to 600 mV, the scan rate to 100 mV / s, and the current range to 100–1000 μA. A CV cycle test was performed to obtain the modified electrode. Figure 5 .

[0088] Example 6

[0089] Applications of graphene three-electrode coplanar standard electrodes in biochemical molecular detection:

[0090] Fourteen standard electrodes with graphene as the electrode modification layer, prepared in Example 1, were used. The electrodes were wetted with anhydrous ethanol, and the edges were wiped dry. Before the ethanol on the graphene disk was completely dry, a 5 mmol / L potassium ferricyanide solution was added, ensuring the solution completely covered the working electrode, auxiliary electrode, and reference electrode. The lead portion of the standard electrode was inserted into the USB interface of a portable electrochemical workstation. The starting potential was set to -300 mV, the ending potential to 600 mV, the scan rate to 100 mV / s, and the current range to 100–1000 μA. CV cycle tests were performed under the same environmental conditions to obtain the desired results. Figure 6 .

[0091] The electrochemical test data for the above 14 graphene three-electrode coplanar standard electrodes are as follows:

[0092]

[0093]

[0094] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0095] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. Technical details not described in detail in this invention can all be implemented using any existing technology in the art. In particular, all technical features not described in detail in this invention can be implemented using any existing technology.

Claims

1. A graphene three-electrode coplanar standard electrode comprising an electrode substrate, characterized in that, Three coplanar electrodes are fixedly disposed on the electrode substrate. From left to right, a first electrode, a second electrode, and a third electrode are arranged on the front side of the electrode substrate. The first electrode includes a first pin (1), a first guide (4), and a first detection layer (7) connected from bottom to top. The second electrode includes a second pin (2) and a second guide (5) connected from bottom to top. The third electrode includes a third pin (3), a third guide (6), and a second detection layer (8) connected from bottom to top. An electrode modification hole (9) is formed by drilling a hole in the electrode substrate and is placed directly above the second electrode and the first detection layer. (7) Directly below, a through hole (10) is provided in the middle of the second guide part (5); a back electrode is provided on the back side of the electrode substrate, specifically including a back pin (11), a back guide part (12) and an electrode trimming ring (13) connected sequentially from bottom to top. The back guide part (12) is provided with the through hole (10). The electrode trimming ring (13) is provided with the electrode trimming hole (9) inside the inner ring. The diameter of the electrode trimming hole (9) is smaller than the inner ring diameter of the electrode trimming ring (13). The electrode trimming ring (13) is used to install the electrode trimming layer. The electrode trimming layer is connected to the back electrode by contacting the electrode trimming ring (13) and connected to the second electrode through the through hole (10). The electrode trimming layer is replaced according to the detection requirements.

2. The graphene three-electrode coplanar standard electrode according to claim 1, characterized in that, The area where the first electrode, the second electrode, the third pin (3), the third guide portion (6), and the back electrode are located is modified with a metal layer as a substrate, the metal layer including a silver layer; a modification layer is disposed on the surface of the first detection layer (7), the modification layer including a carbon layer; a modification layer is disposed on the surface of the second detection layer (8), the modification layer including a silver-silver chloride layer.

3. The graphene three-electrode coplanar standard electrode according to claim 2, characterized in that, The silver layer has a thickness of 5 μm.

4. The graphene three-electrode coplanar standard electrode according to claim 2, characterized in that, The carbon layer has a thickness of 10 μm.

5. A graphene three-electrode coplanar standard electrode according to claim 2, characterized in that, The thickness of the silver-silver chloride layer is 5 μm.

6. The graphene three-electrode coplanar standard electrode according to claim 1, characterized in that, The diameter of the electrode modification layer is not less than the outer ring diameter of the electrode modification ring (13), and the electrode modification layer completely covers the area of ​​the electrode modification hole (9).

7. A graphene three-electrode coplanar standard electrode according to claim 6, characterized in that, The electrode modification layer is hydrophilic graphene, or nanoporous gold, or pure gold, or a metal modified with active enzymes.

8. A graphene three-electrode coplanar standard electrode according to claim 6, characterized in that, An adhesive seal (16) is provided on the back side of the electrode substrate, specifically located at the position of the electrode modification ring (13), to fix the electrode modification layer to the back side of the electrode substrate.

9. A graphene three-electrode coplanar standard electrode according to claim 1, characterized in that, The electrode substrate surface is coated with ink, and the electrode substrate surface is modified with a single layer of ink or multiple layers of ink to form an electrolytic cell, wherein the thickness of a single layer of ink is 25~30 μm.

10. A graphene three-electrode coplanar standard electrode according to claim 1, characterized in that, The electrode substrate is coated with a first layer of ink (14) on the front side. The first layer of ink (14) covers the first pin (1), the second pin (2) and the third pin (3) above, but excludes the electrode area of ​​the first detection layer (7), the electrode modification hole (9) and the second detection layer (8). A second layer of ink (15) is coated on the surface of the first layer of ink (14). The second layer of ink (15) forms a dam structure at the edge of the detection part formed by the first detection layer (7), the electrode modification hole (9) and the second detection layer (8).

11. The application of a graphene three-electrode coplanar standard electrode as described in any one of claims 1 to 10 in biochemical molecular detection.

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