TWI239396B - A fabrication method of chemically modified screen printed electrode and electrochemical testing application thereof - Google Patents

Abstract

The present invention discloses a kind of fabrication method of chemically modified screen printed electrode and electrochemical testing application thereof. The method mixes a modified material and a conducting material used for screen printed electrode uniformly and then directly prints on an electrode back plate using the screen-printed method. The method is simple and the composition is controllable. Not only can the electrode surface be modified, but the properties inside the entire conducting material can be altered due to the addition of the so-called modified material. The modified material includes single or multiple similar or dissimilar special organic compound, polymers, and complex. Under different testing requirements, different modified materials are added for different functions, for example, increasing the current signals for analysis and lowering oxidation potentials and decreasing the impact of interference on the actual testing sample.

Description

1239396 A7 V. Description of the invention (1) Because: The electrode has caused quite a lot of research in the 1990s, and modification can extend the characteristics of the electrode. With proper surface modification, the electrical activity, alkalinity, alkalinity, complexity, and even electrocatalysis can be modified. MIN t 卜 古 # There are many research reports that have found many research institutes: females, and applied in new fields, making the modified electrode itself an important tool in electroanalytical chemistry. For special applications, most of the so-called modifiers are physically or chemically attached to the surface of the electrode after the preparation of the electrode, and / or by the attached method or electrochemical polymerization method. Some of these modifiers are organic compounds, biomolecules, or polymers to change the characteristics of the electrode surface and meet the requirements of so-called special inspection. Kimura et al. Published an electrode surface modification method in 1988. In this method, the surface of a basic pyrolytic graphite electrode (electrolytic mediator) is brought into contact with an electron mediator to generate redox adsorption. For example, a pyrolytic graphite electrode is immersed in a methyl viogen electron mediator for about 10 seconds. After being washed and dried, the electrode modification with an electron mediator on the surface is completed. This modification The subsequent electrode has a good performance for detecting heme (USP 4,595,479). Using a modification method in which a polymer directly covers the electrode surface, the film thickness can be determined by the concentration of the adsorbed polymer. Based on the density of the polymer film, the selective function can be achieved by the detection or interference of the polymer through the limitation of the pore diameter of the polymer film and the charge carried by the polymer film. N. Oyama et al. Made polyethylene mouths in 1980. (Polyvinyl pyridine) is directly adsorbed on the surface of graphite electrodes. The size of this paper is applicable to China National Standard (CNS) A4 (210 X 297 mm) ------------- MW (Please read the back (Please fill in this page again)

I I I I Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 1239396

V. Description of the invention (2)

Electrochem · Soc. 127, 640, 1980), this modification caused the surface environment of strong acidic electrodes' to facilitate the detection of cations. Niki et al. Also adsorbed nitrogen-containing electron mediator compounds and strong acid cation exchange resins containing aromatic private groups on the electrode surface at 1 = 86 years, and prepared electrodes with different electron mediators for different detection. Demand (usp 4, 619, 754). Biosensors mainly use electrochemical detection for electrode pads, which often use biological substances to modify the electrode surface, and there are many ways to modify the electrode surface. Special functional groups are formed on the electrode surface first, and then the functional groups are used to bond with the biological substance to achieve the purpose of attaching the biological substance. TMHerne et al. Used sulfhydryl-containing hydrocarbons and single strands derived from sulfhydryl groups to utilize the characteristics of sulfur-gold bonding to cover the electrode surface with these substances (JACS 1997, 1 19, 8916-8920). . In addition, an electrochemical method is used to polymerize an organic compound or an organic resin having a functional group on the electrode surface so that functions such as CN, CHO, C00H, etc. are generated based on the electrode surface (AndHeux et al., USP 6,217,74). All the above electrode modification methods are modified after electrode preparation. A carbon-filled electrode is produced by mixing carbon powder, mineral oil, and other components, filling a soft solid material into a rod-shaped electrode container, and heating and baking to harden it. Polish the electrode surface before using the electrode. Since the original filling material is solid, there is no need to consider the influence of the solubility of the components on the electrode, and there are more ways to modify the surface of the electrode. In addition to the aforementioned various electrode surface modification methods, et al. Published a method of mixing modified materials with carbon powder and mineral oil at different ratios, then filling a soft solid colloid into an electrode column, and polishing the surface. , Made like a smooth carbon electrode. Ten papers used in this study _ ____4 This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 public love) " 一 -------- -------------- * 1 ^ Loading ------ (Please read the precautions on the back before filling this page) 丨 Order --------- ^ 9. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 1239396

Description of the invention (3, five, (please read the precautions on the back before filling this page), two compounds of octadecyl amine and stearic acid are both solid, and evenly distributed in the solid colloid On the same day, Mori scattered evenly on the electrode surface. The electrode surface has the so-called amino or acid groups. Mi 11 an uses these two functional groups to bind to the DNA to detect DNA (Analytical chemistry 1994, 66, 2943 -2948). Similar inventions as early as 1990, Shaw et al. Will have organic compounds with functional groups, this functional group may be an acid group, test group 'chelating group, complex group, etc., first connected to a non-conductive The polymer with these functional groups and the conductive material are mixed uniformly, and then filled in a glass rod, heated to make an electrode (USP 4, 933, 062), and this filled electrode can be reused. As long as the electrode surface is re-polished. Screen printing electrodes are widely used in the consumer cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs, because they can be manufactured in large quantities, and the cost is low, and they have become more and more important. Generally, the conductive ink is screen-printed directly on an insulating back plate. The conductive material of the electrode is mainly composed of carbon glue, and the pore size of the screen film limits the space where the ink penetrates. Preparation method of screen-printed electrode There is a more detailed description in printing Thick Film Hybrids (Alan Hobby, DEK Printing Machines Ltd., March 1997). Most probably it is a solid insulation backing plate 'may be polyethylene or polypropylene synthetic paper, plastic, ceramics, etc. Conductive ink, which may be a mixture of carbon powder, graphite powder, or metal particles; through a layer of screen holes designed for the shape of the electrode layer, the ink is printed on the insulating back plate through the holes. Screen printing may take more than several times In order to complete the production of the entire electrode, for example, in general, the electrode should have a wire layer, which may be first painted on the back plate with silver glue. The second layer is the electrode layer, which is covered by a second screen. Above the wire, at the same time __ 5 This paper size applies to China National Standard (CNS) A4 (21G X 297 male f) " -----

Printed and printed working electrode area and auxiliary electrode area (or reference electrode, such as a bipolar electrode) with wires under it by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. The material of this electrode area may be graphite layer, carbon glue Layer or other conductive material. The third layer is an insulating layer. Generally, the areas except for the electrodes and the conductive joints are coated with insulating glue to communicate with the outside. Because the ink composition affects the electrode characteristics and the adhesion to the back plate, adding additional components to the ink often results in poor ink utilization, and even cannot be printed on the insulating back plate. If the external components are granular, the Easy to plug screen holes, making screen printing impossible. As mentioned earlier, the surface modification rules of Mil lan and Shaw et al. Cannot be used on screen-printed electrodes. Generally, the surface modification of screen electrodes is similar to the traditional electrode such as smooth carbon electrode or metal electrode. After the electrode is prepared, the surface is modified by physical or chemical methods. ASchreiber et al. Dropped the antibody solution on the surface of the screen electrode in 1997, made the surface of the working electrode adsorb antibodies, and then carried out sandwich-type immunoassay detection (Biosensors & Bioelectronic, 12.11, 1131-1137). In addition, the active material is mixed with a fiber carrier and then screen-printed on the surface of the screen-printed electrode (Republic of China Patent Certificate No. 1070731). A · G · Fogg et al. Used poly-2,6-diaminoacetic acid (poly-L-lysine) to directly coat the surface of the screen electrode, and found that it is helpful for hexa cyano ferrate (HI )) 的 原 原 'and the reoxidation of hexa cyano ferrate (n) (Analytical Proceedings including Analytical Communications, 1995, 32, 209-212). 〇These methods are completed during electrode preparation. After surface modification. C. G. Neuhold et al. Published in 1995 a method for surface modification of screen-printed electrodes. In this method, the liquid modifier, anion-exchanged trioctyl is used. The paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) (Please read the precautions on the back before filling this page)

A7 B7 5. Description of the invention (5) (Please read the notes on the back before filling in this page) Tricapryl methyl ammonium chloride is first mixed with carbon ink, and then the mixed modified carbon is printed by screen printing technology. The ink is printed on a lead ceramic sheet to make a screen printing electrode. Because this trioctylmethylammonium chloride has an adsorption effect on nitrous acid and a pre-concentration function for the detection of nitrite in wastewater (Analyst, 1995, 120, 2377-2380), it can improve the choice of nitrite detection Sex and sensitivity. This modification has limited the detection application in establishing an anion exchange mechanism, and currently only uses nitrite detection as its application. What the invention intends to disclose is a method for modifying the surface of a screen electrode, so that the electrode surface carries a special functional group such as amino groups, hydroxyl groups, and hydroxy groups. Or multiple functional groups. In this method, a so-called modified substance having a functional group is first uniformly mixed with carbon ink, and then printed on a back plate by screen printing technology to make a surface-modified screen printing electrode. Manufacture of various surface functional groups, single or multiple functional groups, screen electrodes. Such a surface-modified electrode can be further chemically modified, combined with biomolecules, or changed the surface characteristics of the electrode to enhance the adsorption of the detection substance and reduce interference to meet the requirements of special detection. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs This paper is sized to the Chinese National Standard (CNS) A4 (210 x 297 mm) 1239396

V. Description of the invention (6) Instructions: Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs Figure 1: Structure of chemically modified screen-printed electrode test strips. The chemically modified screen printing electrode is made of an insulating substrate (n, and a layer of silver wire (2) is printed on the insulating substrate. A science modified carbon glue (3) t is covered on the silver wire and the working electrode area is brushed out) and Auxiliary electrode area 最后 Finally, apply insulating glue (4) to areas other than the electrode connector area (8) and working electrode area, auxiliary electrode area and reference electrode area (6). Figure 1. Enzyme-modified screen printing electrodes Testing. Test results after the acid-based surface-modified screen-printed electrode is combined with / 5-galactosidase. (1) Chemically modified screen-screen electrode (丨 丨 〇c) and the enzyme-bound electrode in a buffer solution. The test results show background values. (2) Results of pAp detection after unmodified electrode (110A) after the same enzyme binding step. (3) Chemically modified screen electrode (丨 丨 〇c) and enzyme-bound electrode Results of detection with pAp. Figure 3: Effect of surface-modified screen-printed electrodes applied to uric acid detection. 110A, 110C, etc. represent the codes of screen-printed electrodes modified with different surface functional groups. Details are shown in Table 1. I ρ (μA) Is the current strength, and Ep (v) Oxidation potential. 8 This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) 1 · i a ^ i ϋ 1 · ϋ n 11 i_i _1 i_i ϋ ϋ iai 请 n (Please read the note on the back first Please fill in this page again for details) Line ·! 1239396 A7 V. Description of the invention (7) Detailed invention The invention relates to a good screen printing electrode made by surface chemical modification. It is produced by chemical modifiers in combination with screen printing technology. The screen printing electrode achieves the modification of the electrode characteristics, and then shows a very good application effect in the actual electrochemical analysis. Through the change of affinity, the oxidation potential decreases and the oxidation current increases, and the traditional unmodified electrochemical analysis faces in the detection The interference problem can be solved. For example, substances such as vitamin C and tetra-acetamidophen (aCetaminophen) contained in blood samples can be determined separately. The surface functional group modified by the present invention can be It is used in combination with other compounds or biomolecules, etc. This so-called functional group chemical modification product contains single or multiple same or different functional groups. Organic compounds containing acid groups For example, dodecanoic acid (lauric acid), myristic acid, stearic acid, and even hexacaic acid all contain a single acid group; and glutaric acid (glutaric acid), decane dicarboxylic acid, dodecanedioic acid, etc. have two acid groups; and ethylenediamine tetraacetic acid (EDTA) and triethylene tetramine hexaacetic acid (triethylene tetramine hexaacetic acid) has multiple acid groups. Take an organic compound containing an amino group as an example. Octa (jeCyiamine) has an amino group and dodecabiamine (1,12-diaminododecane) has an amino group. An organic compound containing a hydroxyl group For example, hexadecanol, octadecanol, and twenty-one alcohol have one hydroxyl group, while polyvinyl alcohol has multiple hydroxyl groups. This There are many types of organic compounds suitable for modifying the screen electrode, and they can be mixed with carbon ink before being directly applied to the Chinese standard (CNS) A4 specification (210X297 mm). -------- --- (Please read the notes on the back before filling out this page) 、 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

1239396 Description of the invention (8) Screen printed on the back plate. The present invention is further illustrated by the following examples, except that: the content is not used to define the scope of the present invention, any; modifications and changes known to those skilled in the art are still covered by the spirit of the invention and Ji Jijun 1 Army 0 Known examples () Surface functional group modification screen printing electrode preparation G Xiao B-based modification (as shown in Table 1), alcohol, benzene, tetrachloro j acetone, chlorosulfonium , Carbon disulfide, pentyl acetate or toluene _ to make a 50% solution, mix this solution with carbon glue in proportion (丨 ― and stir in a closed container for 2 hours before using. Screen printing electrode preparation procedures are first Brush a layer of silver wire on the polypropylene synthetic paper, including the part used as the reference electrode area, bake it for 10 minutes, and then take it out, and then paint a second layer of carbon glue ink containing the modifier to cover the original silver wire. The working electrode and auxiliary electrode area are extended. After finishing the second layer, bake at 75 ° C for 10 minutes. The third layer is an insulating layer covered with an insulating rubber brush except for electrode joints and working electrodes, auxiliary electrodes and reference Outside the electrode area. This The insulation glue is hardened with ultraviolet light, and the electrode preparation is completed. The detailed electrode structure and preparation process are shown in Figure 1. (Please read the note on the back? Matters before filling out this page)

Printed by the Employees 'Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 10 This paper size applies to the Chinese National Standard (CNS) A4 (210 X 297 mm) 1239396 V. Description of the invention (9) A7 B7 Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs

Table 1 Functional group modifiers Functional group type Product name Functional group number Electrode number Unmodified unmodified 0 110A Dodecanedioic acid 1 101A Dodecanedioic acid 1 102A Hexadectoic acid 1 103A C00H Stearyl edible acid 1 110C Hexadecanoic acid 1 112B glutaric acid 2 112A decanedicarboxylic acid 2 101B ethylenediamine tetraacetic acid 4 102B triethylenetetraamine hexaacetic acid 6 112D Li 2 octadecylamine 1 101C aminododecane diamine 2 110D ten Hexadecyl alcohol 1 101D 0H Stearyl alcohol 1 102C Hydroxyl behenyl alcohol 1 110E Polyvinyl alcohol 112E Tetradecanol 1 102D (Please read the precautions on the back before filling out this page) -Pack-- ------ Order --------- · This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 1239396 A7 B7 5 2. Description of the invention (10) Example (2) Modification of electrode surface enzymes

Immerse the working electrode end of the screen-printed electrode (110 A) without surface modification and the screen-printed electrode (110 C) with acid surface modification into a total of 10 ml of 5 mM EDC (1-ethyl-3- ( 3-dimethyl ami nopropyl) carbodimide) and 8mM NHS (N-hydroxy succinimide) in a mixed acetic acid buffer solution (ρΗ5 · 5, 0 · 1M), placed at 37 ° C and shaken for 2 hours. The electrode was washed with acid buffer (pH 7.4, 0 · 1M). The washed electrode end was immersed in 10 ml of 10 U / inl of / 5-galactosidase scale acid buffer solution, and shaken at room temperature for 18 hours. After washing with phosphate buffer solution, it was placed in phosphate buffer solution. Store in liquid at 2-8 ° C until use. Example (3) Testing of enzyme-modified screen-printed electrodes The electrode ends of the enzyme-screen-printed electrodes (110 and 110C) prepared in Example 2 were immersed in PAPG (p-aminopheny) of 0.1 ·. In D-galactopyranoside) phosphate buffer solution, the amount of pap (p-aminophenol) produced was measured by cyclic voltammetry after standing for one hour. PAPG is catalyzed by galactosidase to form PAP. From the amount of PAP produced, it can be inferred whether the stone-galactosidase is bound to the electrode surface, and the difference between the two types of electrodes (unmodified surface functional group and modified surface functional group) can be used to identify the surface functional group. Whether to provide chemical chain binding enzyme function. The test results are shown in Figure 2. The acid-modified stencil electrode has a large amount of enzyme binding on the surface, while the electrode without surface modification cannot be attached to the electrode surface by chemical linking. Although not modified: Electric 12 This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 public love) ------------------- Order ---- ----- line || ^ (Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs! 239396 A7 * " " " B7 V. Description of Invention (11) Pole also shows the formation of PAP, but it may be caused by the electrode's non-adsorption of enzymes or unwashed enzymes, resulting in trace background signals. Amino surface modified zinc and hydroxide surface modified electrodes, whose functional groups provide a more 2 + + binding reaction, is a very common organic reaction, generally familiar with this one can be easily completed by the surgeon. An example of an acid group is used here to prove the results of the decoration. Example (4) Application of Surface Functional Group Modified Electrode to Improve Sensitivity of Uric Acid Detection " The surface functional group modified product used in the present invention can change the surface characteristics of the electrode and reduce the oxidation potential according to the needs of different detections. Increasing the current intensity can reduce the influence of interferences and improve detection sensitivity. In this embodiment, a surface-modified screen electrode is used to detect the signal of uric acid. The method is to immerse the electrode end in a phosphate buffer solution of 10 mg / 100 ml of uric acid, and scan from -0.2 volts to 0.9 volts by cyclic voltammetry to record the peak current intensity and where Potential. The results are shown in Figure 3. Different surface-modified electrodes have different differences in peak current and potential. Taking 112D as an example, the maximum peak current (9.26 microamperes) and the lowest potential (0.23 volts) appeared in the detection of uric acid. Due to the reduction of the redox potential, the redox potential (about 0.3 volts) of tetraethylacetamidobenzene under the same conditions can be greatly different, which can effectively reduce the interference. Example (5) The effect of surface functional group modified electrode on other detections. The same detection method was used to detect the 112D and unmodified screen printing electrode. 13 -------- Order ------- --Line 11 ^ · (Please read the precautions on the back before filling this page) This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) " 1239396 V. Description of the invention (12) V- 5-hydroxytryptophan, acetaminophen, and dopamine were found to have the effect of enhancing the oxidation current. The results are shown in Table 2. A7 B7 Table 2. Analysis results of chemically modified electrodes on typical biochemical components. Concentration of biochemical components (ppm) Peak current (microamperes) Unmodified electrode chemically modified electrode multiples 5-Hydroxytryptophan 10 0.30 1.76 5.87 Acetaminophen 1.5 0.047 0.60 12.77 Dopamine 19 0.16 8.68 54.3 Example (6) Application of Surface Functional Group Modified Electrode to Improve Sensitivity to Aminophenol Detection Aminophenol is a product of PAPG via a / 5-galactosidase-catalyzed reaction. Many immunoassays are detected by electrochemical methods. A model using antibodies or antigens bound by galactosidase. Surface-modified electrodes were used to study the effect on PAP detection. The implementation method is to immerse the electrode tip in a 10mM PAP phosphoric acid solution and detect it by cyclic voltammetry. The experimental results are shown in Table III. It is found that most of the current intensity has enhanced effects such as llOC'llOD and 112B, while the oxidation potentials ιΐ 2Α, 112B, 112D, and 112E have been significantly reduced, or even lowered below zero potential. Body fluid detection avoids interferences such as uric acid (oxidation potential of about 0.2 volts), vitamin C (oxidation potential of about 0.1 volts) and tetra-acetamidophenylbenzene (oxidation potential of about 0.3 volts). Help. 14 This paper has passed the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -------------------- Order -------- -Line (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the Consumer Cooperatives of the Ministry of Economic Affairs and Intellectual Property Bureau printed 1239396 Α7 Β7 V. Description of the invention (13) The effect of electrodes on the determination of amino groups Chemically modified electrodes 1.17 90112D -0.001 1.24 90112E -0.006 1.20 As shown in the above examples, the surface functional group modifier and the screen printing material are mixed uniformly and then screen-printed directly on the electrode back plate, which can achieve the function of directly modifying the electrode surface. Provide surface functional groups for further surface modification, such as binding to proteins, and changes in surface characteristics, which can effectively increase the oxidation current to increase sensitivity and reduce oxidation Segments bits interference component in the specimen such as uric acid, vitamin C and four - Effect of phenol acetylglucosamine. The method of surface modification of the screen printing electrode has not been the same as that of the prior art, and is novel. In terms of detection, it can enhance the sensitivity and reduce the oxidation potential. It has better characteristics than the unmodified screen electrode, and it is progressive. The technology derived from this invention has been applied to the development of uric acid detection products, and will be applicable to clinical detection or instant whole blood uric acid concentration detection at home, which has industrial applicability. This paper size applies to China National Standard (CNS) A4 specification (210 X 297 mm) -------------------- Order --------- line (Please read the notes on the back before filling this page)

Claims (1)

1239396 fzhen | r㈣_— 1 · A screen-printed electrode modified with an acid group on the surface, including an electrically insulating back plate; a conductive film, which is a mixture of an acid-based modification and a conductive material, and covers the electrically insulating back plate to form two Electrode or three-electrode type electrode connector and working electrode 'auxiliary electrode and reference electrode, the content of this acid-based modifier is 0.1% to 30%; an insulating layer covers the terminals and working electrode, auxiliary electrode and Refer to the rest of the electrode. 2. If the surface acid-based modified screen printing electrode of item 1 of the patent application scope, the acid-based modified product has a structure of CHy (CH2) nCOOH, where n = 10-28; the content in the conductive material is 0.1 % 30%. 3. If the surface acid-based screen-printed electrode modified by the surface of the patent application item 1, the acid-based modified product has the structure of HOOC (CH2) n COOH, where η = 3-10; the content in the conductive material is 0 · 1 % 30%. 4 · For the screen printing electrode with acid surface modification on the surface in the first patent claim, the acid-based modified product has (CH2COOH) xN (H) y- CH2- (Cj〇wCH2- Ν (ΗΜαγΟΙΙΑΑ structure, Ν ( H) u (CH2COOH) v and x = 0, 1, 2; y = 2-x; n = 0, 1, 2; z = 2-n; V = 〇, 1, 2; u-2-v, w = 0, l; the content in the conductive material is -30%. 5 · — a kind of surface amino-modified screen printing electrode, including an electrically insulating back plate; a conductive film is an amino-modified material mixed with a conductive material and covered On the electrically insulating back plate, form a two-electrode or three-electrode type electrode joint and a 1239396 VI. Patent application scope 'As the electrode, auxiliary electrode and other parts outside the reference electrode, the content of this amino modifier is 0.1% ~ 30%; an insulating layer covers the two ends of the electrode except the electrode, the guard electrode, the auxiliary electrode and the reference electrode. 6. If the surface amino-modified screen printing electrode with the surface application of item 5 of the patent application scope, the amino-modified product has CH3UH2 The structure of nNH2, let n = 16-2G '· The content in the conductive material is G.1% -30%. Amino-modified screen-printed electrode, the amino-modified product has the structure of NH2 (CH2) nNH2, among which 11 = 6-14; the content in the conductive material is 0.1%-30%. Modified screen printing electrodes, including an electrically insulating back plate; ^ W glue 'is a mixture of hydroxyl-based trimmers and conductive materials and covers the insulating odd plate to form a two-electrode or three-electrode type electrode joint and = As an electrode, auxiliary electrode and reference electrode, the content of this hydroxyl-based modifier is 0.1% to 30%; the insulating layer covers other parts except the joints at both ends of the electrode and the working electrode, auxiliary electrode and reference electrode. The surface-type hydroxyl-modified screen printing electrode of item 8 of the patent scope, the hydroxyl-modified product has a structure of CH3 (CH2) n0H, where n = 14-24; the composition in the conductive material is 0.1 % —30%. 10. If the surface hydroxyl-modified screen printing encapsulation electrode of item 8 of the patent application scope, the hydroxyl-modified product is a polymer having a polyhydroxy group, such as polyvinyl alcohol. ! 239396 ----- k / 、、 Application scope u · A surface functional group modification Screen printing electrode, including an electrically insulating back plate; conductive cymbal, which is a functional group modifier mixed with conductive material and covers the electrically insulating back plate ±, forms a two-electrode or three-electrode type electrode joint, and serves as an electrode and auxiliary electrode And reference electrode, the content of this functional group modifier is 0.1% ~ 30%; an insulating layer covers other parts except the joints at both ends of the electrode, the working electrode, the auxiliary electrode and the reference electrode. 12. For the screen printing electrode with surface functional group modification as described in item 5 of the 5th patent application, the functional group modification is as described in item 2, 3, 4, 6, and 7 of the patent application scope. Item, item 9 or item 10, the total composition of which is from 0.1% to 30%. 13. · A method for detecting uric acid, which is applied to surface functional group-modified electrodes such as item i, item 5, item 8 or item 11 of the scope of patent application. 14. · A method for detecting p-aminophenol, which is applied to surface functional group-modified electrodes such as items 1, 5, 8, or π of the patent application range 0 18