A dry chemical reagent tablet for quantitatively detecting total protein and preparation method thereof

Abstract

The present invention proposes a dry chemical reagent sheet for quantitatively detecting total protein and a preparation method thereof, and relates to the field of chemical reagent sheets. The dry chemical reagent sheet for quantitatively detecting total protein comprises a support layer, a reagent layer and a diffusion layer, wherein the reagent layer is arranged above the support layer, the diffusion layer is arranged above the reagent layer, the diffusion layer comprises a diffusion layer reagent or is formed by a diffusion layer reagent, the diffusion layer reagent comprises an adhesive, a surfactant and particulate matter, and the particulate matter comprises a first particulate matter and a second particulate matter; the number ratio of the first particulate matter to the second particulate matter is 1:(0.25-4), and the difference in particle size between the first particulate matter and the second particulate matter is 10-40 μm. The dry sheet for quantitative detection of total protein provided by the present invention is used for in vitro diagnosis, and its detection result is accurate, storage is stable, and it has the advantages of rapid diagnosis, simple operation, cost saving, etc.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present invention claims the priority of Chinese patent application CN 202411437814.1 filed on October 15, 2024, entitled “A dry chemical reagent sheet for quantitative detection of total protein and its preparation method”, and the entire contents of the above application are incorporated herein by reference. Technical Field

[0003] The invention relates to the field of chemical reagent tablets, and in particular to a dry chemical reagent tablet for quantitatively detecting total protein and a preparation method thereof. Background Art

[0004] Total protein generally refers to serum total protein, which is one of the important items in clinical biochemical tests. In general, serum total protein is often used in clinical practice to reflect liver function, assist in the diagnosis of liver disease, and serve as an observation indicator for the efficacy of treatment. In addition, total protein can also assess individual nutritional status. A decrease in serum total protein levels may indicate malnutrition or digestion and absorption problems. Its normal concentration range is 60-80g / L. However, the wet method commonly used in clinical practice usually requires a large number of manual operation steps such as sample preparation, reagent addition, and reaction monitoring. The operation is complicated and has a high risk of error. At the same time, the detection process usually takes a long time to complete and the cost is relatively high. Its application has always been relatively limited.

[0005] Quantitative dry film testing belongs to dry chemical analysis, which is a technical method widely used in clinical testing and biochemical research. Its core feature is to pre-dry a variety of reaction reagents and fix them on paper or other carriers. Then, during the actual test, the liquid in the sample (such as whole blood, serum, plasma, urine, etc.) is used as the reaction medium to make the components to be tested in the sample react directly with the dry reagent. This reaction usually produces a color change, and qualitative or quantitative analysis is performed through naked eye observation or instrument detection. Compared with traditional wet chemistry, quantitative dry film testing has many advantages such as simple and convenient operation, fast results, low cost, small dosage, easy storage, easy to combine with automated equipment, strong adaptability, and environmental friendliness.

[0006] To this end, we hope to develop a total protein quantitative detection dry film for in vitro diagnosis, which can not only effectively simplify the total protein detection process and reduce the cost of use, but also optimize the application environment and realize convenient and fast POCT (point-of-care testing). Summary of the invention

[0007] In view of the above analysis, the present invention aims to provide a dry chemical reagent sheet for quantitative detection of total protein and a preparation method thereof, so as to simplify the detection process of total protein and reduce the use cost.

[0008] The purpose of the present invention is mainly achieved through the following technical solutions:

[0009] In the first aspect, the present invention provides a dry chemical reagent sheet for quantitatively detecting total protein, comprising a support layer, a reagent layer and a diffusion layer, wherein the reagent layer is arranged above the support layer, the diffusion layer is arranged above the reagent layer, the diffusion layer comprises a diffusion layer reagent or is formed by a diffusion layer reagent, the diffusion layer reagent comprises an adhesive, a surfactant and particulate matter, the particulate matter comprises a first particulate matter and a second particulate matter; the number ratio of the first particulate matter to the second particulate matter is 1:(0.25-4), preferably 1:(0.5-1.5), and the difference in particle size between the first particulate matter and the second particulate matter is 10-40μm, preferably 15-25μm.

[0010] Preferably, the first particulate matter comprises polystyrene microspheres with a particle size ranging from 40 to 80 μm, preferably 45 to 55 μm.

[0011] Preferably, the second particulate matter comprises polystyrene microspheres with a particle size ranging from 10 to 40 μm, preferably 25 to 35 μm.

[0012] Preferably, the amount of surfactant in the diffusion layer reagent is 0.5-0.9 g / m 2 , preferably 0.68-0.73g / m 2 ; The amount of adhesive is 12.5-75g / m 2 , preferably 37.5-62.5g / m 2 ; The dosage of particles is 400-600g / m 2 .

[0013] Preferably, the amount of the first particles in the diffusion layer reagent is 200-300 g / m 2 , preferably 265-280g / m 2 ; The dosage of the second particle is 200-300g / m 2 , preferably 210-220g / m 2 .

[0014] Preferably, in the diffusion layer reagent, the surfactant comprises a fluorine surfactant; and the binder comprises polyisobutylene.

[0015] Preferably, the reagent layer comprises a reagent layer reagent or is formed by a reagent layer reagent, and the reagent layer reagent comprises an alkaline agent, a color developer, a hydrophilic polymer, and a surfactant, wherein the color developer comprises a copper salt and tartaric acid.

[0016] Preferably, the amount of the alkaline agent in the reagent layer is 3-20 g / m 2 , preferably 11-15g / m 2; The dosage of copper salt is 3-15g / m 2 , preferably 8-10g / m 2 ; The dosage of tartaric acid is 4-20g / m 2 , preferably 11-13g / m 2 ; The amount of hydrophilic polymer is 5-50g / m 2 , preferably 20-30g / m 2 ; The dosage of surfactant is 1-10g / m 2 ; preferably 3-8g / m 2 .

[0017] Preferably, in the reagent layer reagent, the alkaline agent includes at least one of lithium hydroxide and potassium hydroxide; in the reagent layer reagent, the hydrophilic polymer includes at least one of PVP, PVA, PAA, and PAM; in the reagent layer reagent, the surfactant includes Triton.

[0018] Preferably, the reagent layer has a thickness of 200-300 μm; and the diffusion layer has a thickness of 200-300 μm.

[0019] Preferably, the support layer comprises transparent resin plastic; and the film thickness of the support layer is 30-200 μm.

[0020] In a second aspect, the present invention provides a method for preparing the reagent sheet, comprising the following steps:

[0021] Step 1: coating the reagent layer reagent on the support layer and drying to obtain the reagent layer;

[0022] Step 2: Spread the diffusion layer reagent on the reagent layer and dry it to obtain a dry chemical reagent sheet.

[0023] Beneficial effects:

[0024] The total protein quantitative detection dry sheet provided by the present invention is a dry chemical method multi-layer membrane reagent dry sheet that can be used for in vitro diagnosis. It has accurate detection results and stable storage, and has the advantages of rapid diagnosis, simple operation, cost saving, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the structure of a dry chemical reagent sheet for quantitatively detecting total protein provided by the present invention.

[0026] Figure 2 This is a test chart of the dry chemical reagent sheet of Example 1 provided by the present invention after serum is added and the color changes (the serum concentrations from left to right are 21 g / L, 65 g / L, and 97 g / L).

[0027] Among them, 1-diffusion layer, 2-reagent layer, 3-support layer. DETAILED DESCRIPTION

[0028] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0029] The present invention provides a total protein quantitative detection dry sheet for in vitro diagnosis. After serum is added to the dry sheet, the total protein in the serum will quickly react with the copper ion component in the dry sheet to generate a purple compound attached to the dry sheet, and the amount of the purple compound is proportional to the concentration of the total protein in the sample. The dry sheet after the reaction is tested by an instrument using a reflected light photometry method, and the quantitative concentration of the total protein in the test serum can be quickly obtained through a concentration curve corresponding to the standard test.

[0030] In a first aspect, the present invention provides a dry chemical reagent sheet for quantitatively detecting total protein, comprising a support layer and a reagent layer, wherein the reagent layer is arranged on the support layer, the reagent layer is the area where a chemical reaction occurs in a substance to be tested, the reagent layer comprises a reagent layer reagent or is formed by a reagent layer reagent, and the reagent layer reagent comprises a color developer that can bind to total protein to produce a color change, a hydrophilic polymer, a surfactant, and an alkaline agent that provides an alkaline environment.

[0031] As a specific embodiment of the present invention, the alkaline agent includes at least one of lithium hydroxide and potassium hydroxide; the amount of the alkaline agent is 3-20 g / m 2 , preferably 11-15g / m 2 .

[0032] As a specific embodiment of the present invention, in the reagent layer reagent, the color developer includes copper sulfate and tartaric acid, wherein the amount of copper sulfate is 3-15g / m 2 , preferably 8-10g / m 2 ; The dosage of tartaric acid is 4-20g / m 2 , preferably 11-13g / m 2 .

[0033] As a specific embodiment of the present invention, in the reagent layer reagent, the hydrophilic polymer can be selected from at least one of polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylic acid (PAA), and polyacrylamide (PAM), and the amount of the hydrophilic polymer is 5-50 g / m 2 , preferably 20-30g / m 2 .

[0034] As a specific embodiment of the present invention, in the reagent layer reagent, the model of PVP can be selected from at least one of K90 (average molecular weight 1300000), K60 (average molecular weight 335000), K30 (average molecular weight 51500), and K15 (average molecular weight 10000); the model of PVA can be at least one of PVA-205, PVA-103, PVA-117, PVA-203, and PVA-217; the model of PAA can be at least one of Mn2000, Mn3000, and Mn5000; the model of PAM can be selected from at least one of 20% ionicity, 30% ionicity, and 50% ionicity.

[0035] As a specific embodiment of the present invention, the amount of surfactant in the reagent layer reagent is 1-10g / m 2 ; preferably 3-8g / m 2 The surfactant is selected from Triton, and the model can be at least one of TritonX-100, TritonX-35, TritonX-165, and TritonX-305.

[0036] As a specific embodiment of the present invention, the reagent layer has an optimized wet film thickness of 300-500 μm. Within this thickness range, the display effect is relatively better, and the dry film thickness is 200-300 μm.

[0037] The color development principle of the present invention is that copper ions react with proteins containing peptide bonds in an alkaline solution, and the generated complex is purple.

[0038] As a specific embodiment of the present invention, the reagent sheet further includes a diffusion layer disposed above the reagent layer.

[0039] As a specific embodiment of the present invention, the diffusion layer includes a diffusion layer reagent or is formed by a diffusion layer reagent, and the diffusion layer reagent includes an adhesive, a surfactant, and particulate matter.

[0040] As a specific embodiment of the present invention, in the diffusion layer reagent, the adhesive is selected from polyisobutylene, and the amount of the adhesive is 12.5-75g / m 2 , preferably 37.5-62.5g / m 2 , more preferably 50g / m 2 As a specific embodiment of the present invention, the molecular weight of polyisobutylene is in the range of 200-3000, preferably 2400.

[0041] As a specific embodiment of the present invention, in the diffusion layer reagent, the surfactant can be selected from fluorosurfactants, and the model can be at least one of FS-31, FS-30, FS-50, FS-60, and FS-81. The amount of the surfactant is 0.5-0.9 g / m 2 , preferably 0.68-0.73g / m 2

[0042] As a specific embodiment of the present invention, in the diffusion layer reagent, the particles include first particles and second particles. The amount of the particles is 400-600 g / m 2 ; Among them, the dosage of the first particle is 200-300g / m 2 , preferably 265-280g / m 2 ; The dosage of the second particle is 200-300g / m 2 , preferably 210-220g / m 2 .

[0043] As a specific embodiment of the present invention, the first particulate matter can be selected from polystyrene microspheres; the average particle size is 40-80 μm, such as 45, 50, 55, 60, 65, 70, 75 μm, etc., preferably 45-55 μm, and more preferably 50 μm.

[0044] As a specific embodiment of the present invention, the second particulate matter can be selected from polystyrene microspheres; the average particle size is 10-40 μm, such as 15, 20, 25, 30, 35 μm, etc., preferably 25-35 μm, and more preferably 30 μm.

[0045] It should be noted that, in the present invention, unless otherwise specified, the particle size of the particulate matter is the average particle size.

[0046] In the present invention, the polystyrene microspheres may be hydrophilic polystyrene microspheres, where carboxyl groups are modified on the surface of the polystyrene microspheres to enhance the adsorption of proteins.

[0047] In the present invention, the serum sample is dropped on the dry sheet, the total protein will be enriched on the first particle and the second particle, the liquid penetrates into the reagent layer, and the reagent in the reagent layer will penetrate into the diffusion layer and combine with the total protein in the sample. The gap difference caused by the particle size control of the first particle and the second particle can more effectively ensure the uniformity and rate of serum diffusion.

[0048] As a specific embodiment of the present invention, the number ratio of the first particles to the second particles is 1:(0.25-4), preferably 1:(0.5-1.5), and more preferably 1:1.

[0049] As a specific embodiment of the present invention, the difference in particle size between the first particle and the second particle is 10-40 μm, such as 15, 20, 25, 30, 35 μm, etc., preferably 15-25 μm. It should be noted that the difference in the present invention refers to an absolute value.

[0050] In the present invention, the diffusion layer is mainly composed of particulate polystyrene microspheres, which are fixed by polyisobutylene as an adhesive. The main functions of the diffusion layer include uniformly diffusing the sample, filtering macromolecular substances and interfering substances in the sample, and protecting the reagent layer.

[0051] As a specific embodiment of the present invention, the diffusion layer preferably has a wet film thickness of 400-600 μm. Within this thickness range, the display effect is relatively better, and the dry film thickness is 200-300 μm.

[0052] As a specific embodiment of the present invention, the support layer includes transparent resin plastic with a transmittance in the visible light range of more than 85%. Specific materials include polyethylene PE, polypropylene PP, polyester methyl methacrylate PMMA, polystyrene PS, polycarbonate PC and polyethylene terephthalate PET, preferably PET.

[0053] As a specific embodiment of the present invention, the film thickness of the support layer is 30-200 μm. It should be noted that within this thickness range, the display effect is relatively better, ensuring that both the incident light source and the reflected light can pass through the support layer.

[0054] like Figure 1 As shown, the dry chemical reagent sheet for quantitative detection of total protein provided by the present invention comprises a diffusion layer 1, a reagent layer 2 and a support layer 3, which are sequentially laminated together from top to bottom through a coating process.

[0055] The working principle of the present invention is to drop the serum sample on the dry sheet and evenly distribute it to the reagent layer below through the diffusion layer. Protein has a high molecular weight, so it will be constrained in the diffusion layer, and the liquid will penetrate into the reagent layer. The reagent layer reagent will also be dispersed in the diffusion layer and react with the protein in the diffusion layer to generate colored compounds. Because the amount of colored compounds is proportional to the total protein concentration in the sample, the amount of colored compounds generated can be measured by reflected light photometry, and then the quantitative concentration of total protein in the serum sample can be calculated based on the sample curve. The specific reaction steps are as follows:

[0056] Total protein + copper ions → colored compounds.

[0057] In a second aspect, the present invention provides a method for preparing a dry chemical reagent sheet for quantitatively detecting total protein, comprising the following steps:

[0058] Step 1: coating the reagent layer reagent on the support layer and drying to obtain the reagent layer;

[0059] Step 2: Spread the diffusion layer reagent on the reagent layer and dry it to obtain a dry chemical reagent sheet.

[0060] As a specific embodiment of the present invention, the method for preparing a dry chemical reagent sheet for quantitative detection of total protein provided by the present invention comprises the following steps:

[0061] Step 1: Preparation and coating of reagent layer

[0062] First, prepare an aqueous solution of tartaric acid containing lithium hydroxide monohydrate. Then prepare an aqueous solution of copper salt, and add the solution to the prepared aqueous solution of tartaric acid containing lithium hydroxide monohydrate, and stir until uniform and without precipitation. Then prepare PVP (K90) solution and TritonX-100 solution respectively. Then, remove the bubbles and surface foam in the mixed solvent, and use a coating machine to coat the selected support layer film. The optional membrane materials include polyethylene PE, polypropylene PP, polyester methyl methacrylate PMMA, polystyrene PS, polycarbonate PC and polyethylene terephthalate PET. The preferred wet film coating thickness is 300-500 μm, and the dry film coated with the reagent layer is obtained by drying.

[0063] Step 2: Preparation and coating of diffusion layer

[0064] Polyisobutylene and fluorosurfactant FS-31 are prepared into a mixed liquid, and then the first particle and the second particle are added; the mixture is stirred evenly and quickly coated on a prepared dry sheet coated with a reagent layer, wherein the preferred ratio of 50 μm and 30 μm polystyrene microspheres is 1:1, the wet film coating thickness is 400-600 μm, and the mixture is dried to obtain a dry sheet for quantitative albumin detection for in vitro diagnosis.

[0065] The dry chemical reagent sheet for total protein for in vitro diagnosis provided by the present invention has the following detection method:

[0066] The dry film is taken out as needed, 10 μL of serum sample is directly added, and after waiting for 5 minutes, the optical density value is tested at a wavelength of 540 nm using an optical densitometer, and the total protein concentration of the test serum sample is calculated based on the relationship curve between the total protein concentration of the dry film and the optical density value provided by the present invention drawn by the standard at different concentrations. Detection limit range: total protein concentration 20-110 g / L.

[0067] The preferred embodiments of the present invention are described in detail below to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0068] In the present invention, the amount of each component in the reagent layer reagent and the diffusion layer reagent is the amount of the listed substances, and does not include the amount of the solvent for dissolving the component.

[0069] Unless otherwise specified, the reagents used in the embodiments of the present invention are all commercially available products.

[0070] Example 1

[0071] 1. Preparation and coating of reagent layer

[0072] First, prepare an aqueous solution of tartaric acid containing lithium hydroxide monohydrate. Then prepare an aqueous solution of copper salt, and add the solution to the prepared aqueous solution of tartaric acid containing lithium hydroxide monohydrate. Stir until uniform and without precipitation. Then prepare PVP (K90) solution and TritonX-100 solution respectively, and the amount of each component of the reagent layer is shown in Table 1. After the mixed solution is stirred evenly, remove the bubbles and surface foam in the mixed solvent, and use a coating machine to coat the selected support layer film. The optional membrane materials include polyethylene PE, polypropylene PP, polyester methyl methacrylate PMMA, polystyrene PS, polycarbonate PC and polyethylene terephthalate PET. The preferred wet film coating thickness is 400μm, and the dry film coated with the reagent layer is dried to obtain a dry film with a dry film thickness of 250μm.

[0073] 2. Preparation and coating of diffusion layer

[0074] Polyisobutylene and fluorinated surfactant FS-31 were prepared into a mixed solution. Then, polystyrene microspheres with particle sizes of 50 μm and 30 μm were added in a ratio of 1:1. The amounts of the components of the diffusion layer were shown in Table 2. The mixture was stirred evenly and quickly coated on the prepared dry film coated with the reagent layer. The wet film coating thickness was 500 μm. The dry film was dried to obtain a dry film for quantitative detection of total protein for in vitro diagnosis, and the dry film thickness was 250 μm.

[0075] Table 1 Reagent layer formula

[0076] Serial number Reagent layer reagent Dosage 1 Copper salt (copper sulfate) <![CDATA[9g / m 2 ]]> 2 tartaric acid <![CDATA[12g / m 2 ]]> 3 Hydrophilic polymer: PVP (K90) <![CDATA[25g / m 2 <!-- 5 -->]]> 4 Surfactant (TritonX-100) <![CDATA[5g / m 2 ]]> 5 Alkaline agent (lithium hydroxide) <![CDATA[13g / m 2 ]]>

[0077] Table 2 Diffusion layer formula

[0078]

[0079] Example 2

[0080] This embodiment is basically the same as embodiment 1, except that, during the preparation of the reagent layer, the mixed solution is stirred evenly, and the amount of the hydrophilic polymer used is 20 g / m 2 ; The dosage of surfactant is 3g / m 2 .

[0081] Example 3

[0082] This embodiment is basically the same as embodiment 1, except that in the process of preparing the diffusion layer, the amount of polyisobutylene (molecular weight 2400) used is 50 g / m 2 The amount of surfactant used is (FS-31) 0.9g / m 2 , configured into a mixed liquid.

[0083] Example 4

[0084] This embodiment is basically the same as the embodiment 1, except that, during the preparation of the diffusion layer, polystyrene microspheres with particle sizes of 50 μm and 30 μm are added in a quantity ratio of 1:2.

[0085] Example 5

[0086] This embodiment is basically the same as the embodiment 1, except that, during the preparation of the diffusion layer, polystyrene microspheres with particle sizes of 60 μm and 20 μm are added in a quantity ratio of 1:1.

[0087] Example 6

[0088] This embodiment is basically the same as the embodiment 1, except that, during the preparation of the diffusion layer, polystyrene microspheres with particle sizes of 90 μm and 50 μm are added in a quantity ratio of 1:1.

[0089] Example 7

[0090] This embodiment is basically the same as the embodiment 1, except that, during the preparation of the diffusion layer, polystyrene microspheres with particle sizes of 50 μm and 30 μm are added in a quantity ratio of 1:5.

[0091] Comparative Example 1

[0092] This comparative example is basically the same as Example 1, except that, during the preparation of the reagent layer, no Triton X-100 solution is added.

[0093] Comparative Example 2

[0094] This comparative example is basically the same as Example 1, except that, during the preparation of the diffusion layer, only polystyrene microspheres with a particle size of 30 μm are added as particulate matter.

[0095] Comparative Example 3

[0096] This comparative example is basically the same as Example 1, except that, during the preparation of the diffusion layer, only polystyrene microspheres with a particle size of 50 μm are added as particulate matter.

[0097] Experimental example

[0098] Evaluation of the ability of the prepared dry slide to detect total serum protein concentration

[0099] Take 3 small pieces (each piece size 1.5cm*1.5cm) of the same batch of total protein quantitative detection dry pieces prepared by the present invention and used for in vitro diagnosis, and drip serum samples with total protein standard concentrations of 21, 34, 65, 84 and 97g / L respectively (wherein, serum samples with concentrations of 21g / L, 65g / L and 97g / L are commercially available composite calibrants, and the remaining concentrations are the dilution concentrations of commercially available composite calibrants), wait for 5min, and test the optical density value at a wavelength of 540nm with an optical densitometer, wherein the corresponding optical density value also presents a gradient change relationship. The test results of the embodiment and the comparative example are shown in Table 3.

[0100] Commercially available composite calibrants with concentrations of 21 g / L, 65 g / L, and 97 g / L were added dropwise to the Example and the Comparative Example for reaction. The coefficient of variation CV was calculated by repeating 10 times. The results are shown in Table 4.

[0101] The color comparison results of Example 1 when adding three concentrations (21, 65, and 97 g / L) of commercially available composite calibrants are as follows: Figure 2 As shown, the three circular spots with albumin concentrations from low to high are uniform in size and color, and the colors range from light to dark.

[0102] Table 3 Test results of Examples S1-S7 and Comparative Examples D1-D3

[0103]

[0104] Table 4 Repeatability test results of Examples S1-S7 and Comparative Examples D1-D3

[0105]

[0106]

[0107] As can be seen from Tables 3-4, compared with Comparative Examples 1-3, the correlation coefficient r2 of Example 1 is 0.9723, indicating that the optical density and albumin concentration present a good linear relationship, and the slope of Example 1 is 0.0069, indicating that the optical density difference between high concentration and low concentration is large, and the color difference is obvious. In addition, the coefficient of variation CV value of Example 1 is less than that of Comparative Examples 1-3, and the repeatability meets the requirements, and the precision is higher.

[0108] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A dry chemical reagent sheet for quantitative detection of total protein, comprising a support layer, a reagent layer and a diffusion layer, wherein the reagent layer is arranged above the support layer, and the diffusion layer is arranged above the reagent layer, characterized in that: The diffusion layer includes a diffusion layer reagent or is formed by a diffusion layer reagent, the diffusion layer reagent includes a binder, a surfactant and particles, and the particles include first particles and second particles; The number ratio of the first particles to the second particles is 1:(0.25-4), preferably 1:(0.5-1.5), The difference in particle size between the first particles and the second particles is 10-40 μm, preferably 15-25 μm.

2. The reagent sheet according to claim 1, characterized in that The first particulate matter includes polystyrene microspheres with a particle size of 40-80 μm, preferably 45-55 μm; And / or, the second particulate matter comprises polystyrene microspheres with a particle size of 10-40 μm, preferably 25-35 μm.

3. The reagent sheet according to any one of claims 1 to 2, characterized in that: In the diffusion layer reagent, The dosage of surfactant is 0.5-0.9g / m 2 , preferably 0.68-0.73g / m 2 ; And / or, the amount of adhesive is 12.5-75g / m 2 , preferably 37.5-62.5g / m 2 ; And / or, the amount of particles is 400-600g / m 2 ; Preferably, The dosage of the first particle is 200-300g / m 2 , preferably 265-280g / m 2 ; and / or, the amount of the second particulate matter is 200-300g / m 2 , preferably 210-220g / m 2 .

4. The reagent sheet according to any one of claims 1 to 3, characterized in that: In the diffusion layer reagent, the surfactant includes a fluorinated surfactant; And / or, the adhesive comprises polyisobutylene.

5. The reagent sheet according to any one of claims 1 to 4, characterized in that: The reagent layer includes a reagent layer reagent or is formed by a reagent layer reagent, and the reagent layer reagent includes an alkaline agent, a color developer, a hydrophilic polymer, and a surfactant, wherein the color developer includes a copper salt and tartaric acid.

6. The reagent sheet according to any one of claims 1 to 5, characterized in that: In the reagent layer reagent, The dosage of alkaline agent is 3-20g / m 2 , preferably 11-15g / m 2 ; And / or, the amount of copper salt is 3-15g / m 2 , preferably 8-10g / m 2 ; And / or, the amount of tartaric acid is 4-20g / m 2 , preferably 11-13g / m 2 ; And / or, the amount of hydrophilic polymer is 5-50g / m 2 , preferably 20-30g / m 2 ; And / or, the amount of surfactant is 1-10g / m 2 ; preferably 3-8g / m 2 .

7. The reagent sheet according to any one of claims 1 to 6, characterized in that: In the reagent layer reagent, the alkaline agent includes at least one of lithium hydroxide and potassium hydroxide; And / or, in the reagent layer reagent, the hydrophilic polymer includes at least one of PVP, PVA, PAA, and PAM; And / or, in the reagent layer reagent, the surfactant includes Triton.

8. The reagent sheet according to any one of claims 1 to 7, characterized in that: The thickness of the reagent layer is 200-300 μm; And / or, the diffusion layer has a thickness of 200-300 μm.

9. The reagent sheet according to any one of claims 1 to 8, characterized in that: The support layer includes transparent resin plastic; Preferably, the support layer has a thickness of 30-200 μm.

10. A method for preparing a reagent sheet according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: coating the reagent layer reagent on the support layer and drying to obtain the reagent layer; Step 2: Spread the diffusion layer reagent on the reagent layer and dry it to obtain a dry chemical reagent sheet.

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