Aerogel colorimetric diagnostic test paper with ultra-long shelf life, preparation method and application thereof

Abstract

The present invention discloses an aerogel colorimetric diagnostic test paper with an ultra-long shelf life, and a preparation method and application thereof. The preparation method comprises the following steps: firstly, a hydrophilic and hydrophobic patterned semi-enclosed paper substrate is prepared by screen printing and ink, and then a gel prepolymer solution and a copper ion detection reagent are prepared, and then the detection reagent is loaded into the aerogel three-dimensional network by a one-pot method, and further combined with the fiber array of the paper base, and the ultra-long shelf life aerogel colorimetric diagnostic test paper is obtained after freeze drying. The aerogel colorimetric diagnostic test paper prepared in the present invention has a long shelf life and high sensitivity, can obtain color intensity uniformly, quickly and stably, realizes uniform display of colorimetric signals, and has good application prospects in copper ion detection.

Description

Technical Field

[0001] The invention belongs to the field of detection, and particularly relates to an aerogel colorimetric diagnostic test paper with an ultra-long shelf life, and a preparation method and application thereof. Background Art

[0002] Paper-based colorimetric sensor strips are widely used in the field of rapid diagnosis due to their low cost, easy preparation, convenience and portability. Although research on paper test strips in terms of their manufacturing process and detection technology has progressed rapidly in recent years, most of today's paper-based colorimetric rapid detection strips need to be stored in specific containers due to the instability of the detection reagents. Not only do they have a short shelf life, but they also require operators to prepare them immediately when they are used, which weakens the simplicity and rapidity of paper-based detection. This is because when the detection reagents are deposited on the paper fiber array, they are easily affected by factors such as oxygen, moisture and light in the air, causing the pre-deposited detection reagents to denature and decrease in effectiveness, resulting in an extremely limited shelf life for the paper-based detection strips. Summary of the invention

[0003] The primary purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a method for preparing an aerogel colorimetric diagnostic test paper with an ultra-long shelf life.

[0004] Another object of the present invention is to provide an aerogel colorimetric diagnostic test paper with an ultra-long shelf life prepared by the method.

[0005] Another object of the present invention is to provide an application of the aerogel colorimetric diagnostic test paper with an ultra-long shelf life.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A method for preparing an aerogel colorimetric diagnostic test paper with an ultra-long shelf life comprises the following steps:

[0008] (1) Preparation of hydrophilic and hydrophobic patterned semi-enclosed paper substrate:

[0009] A hydrophilic pattern area with a hydrophilic-hydrophobic boundary and a closed bottom is printed on paper by screen printing and ink, and a patterned hydrophilic detection area is obtained after UV curing;

[0010] (2) Preparation of acrylamide prepolymer solution (gel prepolymer solution):

[0011] Dissolve acrylamide in a glycerol aqueous solution, add a cross-linking agent N,N-methylenebisacrylamide (MBA), and stir until a clear and transparent state to obtain an acrylamide prepolymer solution;

[0012] (3) Preparation of copper ion detection reagent:

[0013] Dissolve hydroxylamine hydrochloride in glycerol aqueous solution to obtain hydroxylamine hydrochloride glycerol aqueous solution (detection reagent 1); dissolve 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline in methanol to prepare a saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution (detection reagent 2);

[0014] (4) Preparation of aerogel test paper for copper ion colorimetric detection:

[0015] The acrylamide prepolymer solution obtained in step (2), the hydroxylamine hydrochloride glycerol aqueous solution (detection reagent 1) obtained in step (3) and the saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution (detection reagent 2) are mixed evenly, and then the initiator solution is added and shaken to mix evenly to obtain a gel mixture; the gel mixture is then added dropwise to the patterned hydrophilic detection area obtained in step (1), and then transferred to a vacuum environment for reaction, freeze-dried, and a copper ion colorimetric detection aerogel test paper is obtained, that is, the aerogel colorimetric diagnostic test paper with an ultra-long shelf life.

[0016] The pattern described in step (1) can be designed according to actual needs, such as a customized pattern.

[0017] The size and shape of the patterned hydrophilic detection area described in step (1) can be designed according to actual needs; preferably, the patterned hydrophilic detection area is circular, and its diameter is 2 to 6 mm.

[0018] The hydrophilic-hydrophobic patterned semi-enclosed paper substrate described in step (1) is prepared by a UV curing-screen printing method, and the specific steps are as follows:

[0019] Use a scraper to print the hydrophobic ink on the paper through a patterned screen. The ink penetrates into the paper to form a hydrophobic area, and the unpenetrated part is the detection area. It is then dried by UV light to complete the construction of the hydrophilic and hydrophobic boundary on the front side of the paper. Then turn the paper over and print the hydrophobic ink on the detection area through the screen using a scraper. The ink penetrates into the paper downward and is dried by UV light to form a patterned hydrophilic detection area with a closed bottom.

[0020] The conditions for UV light irradiation drying are: wavelength of 300nm, irradiation time of 2 to 10s.

[0021] The hydrophobic ink described in step (1) is UV light-curable ink or UV light-curable wax; preferably, it is UV light-curable transparent ink.

[0022] The paper described in step (1) is conventional paper in the art; preferably office paper, commercial filter paper or hand-made paper; more preferably double-circle qualitative filter paper 102#, Whatman 4# filter paper or hand-made paper; further preferably double-circle qualitative filter paper 102#.

[0023] The basis weight of the hand-made paper is 60-80 g / m 2 .

[0024] The volume percentage of glycerol in the glycerol aqueous solution described in step (2) is 0% to 80%, preferably 20% to 40%.

[0025] The concentration of acrylamide in the acrylamide prepolymer solution in step (2) is 480-960 g / L, and the concentration of N,N-methylenebisacrylamide is 10-20 g / L.

[0026] The volume percentage of glycerol in the glycerol aqueous solution in step (3) is 0% to 80%; preferably 60% to 80%; more preferably 60% by volume.

[0027] The concentration of the hydroxylamine hydrochloride glycerol aqueous solution in step (3) is 80-200 g / L, preferably 100-200 g / L, and more preferably 100 g / L.

[0028] The acrylamide prepolymer solution, the hydroxylamine hydrochloride glycerol aqueous solution and the saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution described in step (4) can be mixed in any volume ratio; the volume ratio is preferably 1:1:1.

[0029] The initiator described in step (4) is at least one of ammonium persulfate (APS), potassium persulfate, azobisisobutyramidine hydrochloride (AIBA) and azobisisobutyronitrile (AIBN).

[0030] The concentration of the initiator solution in step (4) is 5% to 20% by mass, preferably 10% by mass.

[0031] The volume ratio of the initiator solution to the acrylamide prepolymer solution in step (4) is 1:5 to 10, preferably 1:5.

[0032] In step (4), the gel mixture I is added to the patterned hydrophilic detection area according to the size of the detection area; the area ratio of the gel mixture I to the detection area is about 0.26L / m 2 (The diameter of the circular detection area is 3 to 6 mm, and the amount of gel mixture I is 5 to 30 μL).

[0033] The reaction conditions in step (4) are: reaction at room temperature under vacuum for 1 to 4 hours; preferably: reaction at room temperature under -1 MPa vacuum for 2 hours.

[0034] The freeze-drying temperature in step (4) is -40°C to -20°C.

[0035] The freeze-drying time in step (4) is 12 to 48 hours.

[0036] An aerogel colorimetric diagnostic test paper with an ultra-long shelf life is prepared by any of the methods described above.

[0037] The application of the ultra-long shelf life aerogel colorimetric diagnostic test paper in detecting divalent copper ions, wherein the application is for non-disease diagnosis purposes.

[0038] A method for detecting divalent copper ions for non-disease diagnosis purposes, comprising the following steps:

[0039] (A) at least 5 standard sample solutions with concentration gradients are respectively added dropwise to the detection area of ​​the above-mentioned ultra-long shelf life aerogel colorimetric diagnostic test paper for reaction, dried at room temperature after the reaction, and then the color intensity of the aerogel after the reaction is obtained by a scanner, and then a standard curve is drawn with the concentration of the standard sample solution; wherein the standard sample solution is a divalent copper ion solution;

[0040] (B) dropping the sample solution to be tested into the detection area of ​​the above-mentioned ultra-long shelf life aerogel colorimetric diagnostic test paper for reaction, drying at room temperature after the reaction, and then obtaining the color intensity of the aerogel after the reaction by a scanner, and then obtaining the concentration or content of the divalent copper ion solution in the sample solution to be tested by drawing a standard curve according to step (A).

[0041] The temperature range of the detection is 4°C to 65°C.

[0042] The concentration of the divalent copper ion solution in step (A) is in the range of 0 to 50 ppm, preferably 0 to 30 ppm; more preferably 0.3 to 30 ppm.

[0043] The reaction time in steps (A) and (B) is 4 to 30 minutes; preferably 4 to 10 minutes. The aerogel absorbs the solution faster, the solute exchange rate is faster, and the color reaction after complexation is more complete. Therefore, in a relatively unit time, for aerogels and hydrogels of equal area with the same concentration and volume of standard solution concentration, the color intensity of the aerogel is greater than that of the hydrogel. The wide time range is selected to ensure sufficient color reaction, but rapid detection generally does not exceed 30 minutes.

[0044] Compared with the prior art, the present invention has the following advantages and effects:

[0045] 1. In the present invention, acrylamide prepolymer solution and a detection reagent (a glycerol aqueous solution system composed of hydroxylamine hydrochloride and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) solution are mixed, and then an initiator or a cross-linking agent is added and shaken evenly, and quantitatively transferred to a patterned semi-enclosed paper substrate, and after a period of reaction at room temperature, a hydrogel three-dimensional network and a paper-based fiber array are entangled with each other to obtain a hydrogel, and then after freeze-drying, a copper ion colorimetric detection aerogel paper test paper with a prolonged shelf life is obtained.

[0046] 2. The present invention loads the detection reagent into the aerogel three-dimensional network through a one-pot method, and further combines it with the paper-based fiber array, so that the object to be detected reacts with the anchored detection reagent to develop color, thereby achieving uniform display of the colorimetric signal.

[0047] 3. The copper ion colorimetric detection aerogel paper test paper in the present invention is a paper-based detection aerogel obtained by loading the detection reagent in the hydrogel on the paper base, and freeze-drying the paper-based detection aerogel, that is, fixing the detection reagent in the aerogel network in the fiber array, and realizing rapid colorimetric detection after adding the test liquid dropwise. Under sealed and light-proof conditions, the influence of water, oxygen and light is isolated, and the detection reagent is evenly dispersed and protected in the polymer network of the aerogel, so the shelf life of the shelf colorimetric test paper is greatly extended. At the same time, due to the rapid swelling characteristics and excellent hydrophilic properties of the aerogel, it can quickly absorb the sample liquid to be tested, dissolve the detection reagent, and promote the establishment of the solution environment required for the detection, and finally realize the acquisition of uniform, rapid and stable color intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The present invention is a schematic diagram of the preparation process of the aerogel test paper for colorimetric detection of copper ions.

[0049] Figure 2 This is a colorimetric signal standard curve of the copper ion colorimetric detection aerogel test paper prepared in Example 1.

[0050] Figure 3 This is a test result diagram of the detection sensitivity of the copper ion colorimetric detection hydrogel test paper and aerogel test paper prepared in Example 1 under constant temperature and humidity.

[0051] Figure 4 The figure is the actual detection effect and colorimetric signal curve of the copper ion colorimetric detection aerogel test paper prepared in Example 4; wherein (a) is the actual detection color intensity of the copper ion colorimetric detection aerogel test paper at different test liquid drop amounts; (b) is the color intensity uniformity distribution at different concentrations; (c) is the color intensity curve at different test liquid drop amounts; and (d) is the three-dimensional distribution diagram of the detection signal under high concentration conditions.

[0052] Figure 5The figure is a graph showing the change and comparison of the colorimetric signal intensity of the copper ion colorimetric detection aerogel test paper and the conventional copper ion detection test paper as a function of storage time (1 to 14 days) prepared in Example 5; wherein (a) is the change of the detection effectiveness of the conventional paper-based detection test paper as a function of time; and (b) is the change of the detection effectiveness of the copper ion colorimetric detection aerogel test paper as a function of time.

[0053] Figure 6 It is a graph showing the change and comparison of the colorimetric signal intensity of the copper ion colorimetric detection hydrogel and aerogel test paper prepared in Example 5 and the conventional copper ion detection test paper with the storage time (1 to 180 days).

[0054] Figure 7 This is a graph showing the change in the colorimetric signal intensity of the copper ion colorimetric detection aerogel test paper prepared in Example 6 over the storage time (50 ppm). DETAILED DESCRIPTION

[0055] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art. The test methods for which specific experimental conditions are not specified in the following examples are usually in accordance with conventional experimental conditions. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained commercially.

[0056] The pattern-customized screen printing plate involved in the embodiment of the present invention was purchased from Kaimao Technology (Shenzhen) Co., Ltd.; UV light-curing transparent ink (hereinafter referred to as UV light-curing ink) was purchased from Guangzhou Shangcai Printing Materials Co., Ltd.; double-circle qualitative filter paper 102# was purchased from Si Tuofan Technology (Hangzhou) Co., Ltd.; Whatman4# filter paper was purchased from Hangzhou Wohua Filter Paper Co., Ltd.; the hand-made paper was obtained by copying commercially available pulp board (pulp board purchased from Guangzhou Paper Mill), with a basis weight of 60-80 g / m 2 .

[0057] The preparation method of the hydroxylamine hydrochloride glycerol aqueous solution involved in the embodiment of the present invention is as follows: dissolve hydroxylamine hydrochloride in a glycerol aqueous solution (the volume fraction of glycerol in the glycerol aqueous solution is 0 to 80%, preferably 40 to 80%) to obtain a hydroxylamine hydrochloride glycerol aqueous solution (concentration is 80 g / L to 200 g / L).

[0058] The preparation method of the saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution involved in the embodiment of the present invention is as follows: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline is dissolved in methanol to prepare a saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution.

[0059] The preparation method of the acrylamide glycerol aqueous solution involved in the embodiment of the present invention is as follows: dissolving acrylamide in a glycerol aqueous solution (the volume fraction of glycerol in the glycerol aqueous solution is 0-80%, preferably 20-40%) to obtain an acrylamide glycerol aqueous solution.

[0060] Example 1: Detection of divalent copper ions

[0061] (1) Preparation of hydrophilic and hydrophobic patterned semi-enclosed paper substrate: Figure 1 As shown, a circular hydrophilic pattern area with a clear hydrophilic-hydrophobic boundary and a closed bottom is printed on the double-circle qualitative filter paper 102# using pattern-customized screen printing and UV light-cured transparent ink, with a diameter of 6mm. Specifically, a hydrophobic UV light-cured ink is printed on the double-circle qualitative filter paper 102# through a patterned screen with a scraper, and the ink penetrates into the paper to form a hydrophobic area, and the unpenetrated part is the detection area. Further, under UV light irradiation, the UV light wavelength is 300nm, and the irradiation time is 10s. The ink dries and the construction of the hydrophilic-hydrophobic boundary on the front of the paper is completed; the paper is further turned over, and the UV light-cured ink is printed on the above-mentioned detection area through a scraper through a screen, and the ink infiltrates downward into the paper. After UV light irradiation, the UV light wavelength is 300nm, and the irradiation time is 2s, it is dried to form a patterned hydrophilic detection area with a closed bottom.

[0062] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 80 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 80%), 1 mL of acrylamide prepolymer solution (obtained by adding the crosslinking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 960 g / L acrylamide, the mass concentration of N,N-methylenebisacrylamide is 20 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 20%) are mixed evenly, and then 200 μL of 10% ammonium persulfate aqueous solution is added, after shaking evenly, 30 μL is drawn with a pipette and dropped into the circular unit detection area with a diameter of 6 mm prepared in step (1). Then transfer to a vacuum environment with a vacuum degree of -1 MPa, react at room temperature for 2 hours to obtain a hydrogel test paper for colorimetric detection of copper ions, and finally freeze-dry at -20°C for 24 hours to obtain aerogel test paper for colorimetric detection of copper ions.

[0063] (3) Detection of divalent copper ions: 15 μL of a prepared 10 ppm divalent copper ion standard solution (copper sulfate pentahydrate, the same below) was added dropwise to the 6 mm circular unit detection area filled with aerogel. After 10 minutes, the color intensity of the aerogel after the reaction was obtained by scanning (the scanner used was Epson Perfection V39 Epson scanner, the same below). Then input Figure 2The copper ion standard curve function shown (within the copper ion concentration range of 0 to 1000 ppm, various copper ion standard solutions with different concentration gradients are prepared, the color intensity on the paper-based aerogel test paper is measured, the curve is drawn, and the copper ion standard curve function is obtained after fitting), and the concentration of divalent copper ions is 9.8 ppm.

[0064] (4) Further test the detection sensitivity of copper ion colorimetric detection hydrogel test paper and aerogel test paper under constant temperature and humidity: 15 μL of prepared divalent copper ion standard solution of different concentrations was taken and the hydrogel was dripped onto the copper ion colorimetric detection hydrogel test paper and aerogel test paper respectively. The results are as follows Figure 3 As shown: The color intensity of the copper ion colorimetric detection aerogel is greater than that of the copper ion colorimetric detection hydrogel, and it has better detection sensitivity.

[0065] Example 2: Detection of divalent copper ions

[0066] (1) Preparation of hydrophilic-hydrophobic patterned semi-enclosed paper substrate: Using screen printing with customized patterns and UV light-curing ink, a circular hydrophilic pattern area with a diameter of 5 mm and a clear hydrophilic-hydrophobic boundary and a closed bottom was printed on Whatman 4#. The specific preparation method is the same as in Example 1.

[0067] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 150 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 60%), 1 mL of saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution, and 1 mL of acrylamide prepolymer solution (obtained by adding the cross-linking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 480 g / L, the mass concentration of N,N-methylenebisacrylamide is 10 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 40%) are mixed evenly, and then 200 μL of 8% ammonium persulfate aqueous solution is added, and after shaking evenly, 21 μL is taken with a pipette and dropped into the circular unit detection area with a diameter of 5 mm prepared in step (1). Then it was transferred to a vacuum environment (-1MPa), reacted at room temperature for 2 hours, and finally freeze-dried at -20°C for 36 hours to obtain copper ion colorimetric detection aerogel test paper.

[0068] (3) Detection of divalent copper ions: 10 μL of a prepared 10 ppm divalent copper ion standard solution was added dropwise to a 5 mm circular unit detection area filled with aerogel. After 6 minutes, the color intensity of the aerogel after the reaction was obtained by a scanner. Then, the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1), and the concentration of divalent copper ions was calculated to be 9.7 ppm.

[0069] Example 3: Detection of divalent copper ions

[0070] (1) Preparation of hydrophilic and hydrophobic patterned semi-enclosed paper substrate: Using screen printing and UV light-curing ink with customized patterns, the substrate was prepared with a basis weight of 60 g / m 2 The hand-made paper is printed with a circular hydrophilic pattern area having a clear hydrophilic-hydrophobic boundary and a closed bottom, with a diameter of 4 mm. The specific preparation method is the same as that of Example 1.

[0071] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 200 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 60%), 1 mL of saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution, and 1 mL of acrylamide prepolymer solution (obtained by adding the cross-linking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 480 g / L, the mass concentration of N,N-methylenebisacrylamide is 10 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 40%) are mixed evenly, and then 200 μL of 15% azobisisobutyronitrile aqueous solution is added, and after shaking evenly, 13.3 μL is taken with a pipette and dropped into the circular unit detection area with a diameter of 4 mm prepared in step (1). Then it was transferred to a vacuum environment (-1MPa), reacted at room temperature for 2 hours, and finally freeze-dried at -36°C for 48 hours to obtain copper ion colorimetric detection aerogel test paper.

[0072] (3) Detection of divalent copper ions: 4.3 μL of the prepared 10 ppm divalent copper ion standard solution was added dropwise to the 4 mm circular unit detection area filled with aerogel. After 5 minutes, the color intensity of the aerogel after the reaction was obtained by scanning. Then, the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1), and the concentration of divalent copper ions was calculated to be 9.5 ppm.

[0073] Example 4: Detection of divalent copper ions

[0074] (1) Preparation of hydrophilic-hydrophobic patterned semi-enclosed paper substrate: A circular hydrophilic pattern area with a clear hydrophilic-hydrophobic boundary and a closed bottom was printed on A4 office paper using screen printing with customized patterns and UV light-curing ink. The diameter was 3 mm. The specific preparation method was the same as in Example 1.

[0075] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 150 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 60%), 1 mL of saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution, and 1 mL of acrylamide prepolymer solution (obtained by adding the cross-linking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 960 g / L, the mass concentration of N,N-methylenebisacrylamide is 20 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 40%) are mixed evenly, and then 100 μL of 20% potassium persulfate aqueous solution is added, and after shaking evenly, 7.5 μL is taken with a pipette and dropped into the circular unit detection area with a diameter of 3 mm prepared in step (1). Then it was transferred to a vacuum environment (-1MPa), reacted at room temperature for 2 hours, and finally freeze-dried at -40°C for 12 hours to obtain copper ion colorimetric detection aerogel test paper.

[0076] (3) Detection of divalent copper ions: 2.5 μL of 10 ppm divalent copper ion standard solution was added dropwise to the 3 mm circular unit detection area filled with aerogel. After 5 min, the color intensity of the aerogel after the reaction was obtained by scanning. Then, the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1), and the concentration of divalent copper ions was calculated to be 9.5 ppm.

[0077] (4) Further testing the uniformity of the colorimetric signal of the copper ion colorimetric detection aerogel test paper in the circular detection area: taking different volumes (5, 10, 15, 20 μL) of divalent copper ion standard solution (concentration of 1, 5, 10, 20, 50, 100 ppm) respectively, and adding them dropwise to the circular unit detection area with a diameter of 3 mm prepared in the above step (1).

[0078] The results are as follows Figure 4 As shown: The copper ion colorimetric detection aerogel test paper achieves uniform color development at all standard solution concentrations and addition amounts, without the "coffee ring effect" ( Figure 4 (a)), as well as Figure 4 As shown in (b), within the radial color grayscale fluctuation range, the color intensity of the copper ion colorimetric detection aerogel test paper remains stable, which is consistent with Figure 4 The three-dimensional distribution of color intensity in (d) is consistent; and Figure 4 As shown in (c), as the volume of the sample solution added per unit drop increases, the sensitivity of the copper ion aerogel detection test paper increases.

[0079] Example 5: Detection of divalent copper ions

[0080] (1) Preparation of hydrophilic-hydrophobic patterned semi-enclosed paper substrate: Using screen printing with customized patterns and UV light-curing ink, a circular hydrophilic pattern area with a clear hydrophilic-hydrophobic boundary and a closed bottom was printed on double-circle qualitative filter paper 102#, with a diameter of 3 mm. The specific preparation method is the same as in Example 1.

[0081] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 120 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 60%), 1 mL of saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution, and 1 mL of acrylamide prepolymer solution (obtained by adding the cross-linking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 960 g / L, the mass concentration of N,N-methylenebisacrylamide is 20 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 40%) are mixed evenly, and then 100 μL of 20% potassium persulfate aqueous solution is added, and after shaking evenly, 7.5 μL is taken with a pipette and dropped into the circular unit detection area with a diameter of 3 mm prepared in step (1). Then it was transferred to a vacuum environment (-1MPa) and reacted at room temperature for 2 hours to obtain a copper ion colorimetric detection hydrogel test paper, which was further freeze-dried at -40°C for 24 hours to obtain a copper ion colorimetric detection aerogel test paper.

[0082] (3) Detection of divalent copper ions: 3.75 μL of 10 ppm divalent copper ion standard solution was added dropwise to the 3 mm circular unit detection area filled with aerogel of the copper ion colorimetric detection aerogel test paper. After 10 minutes, the color intensity of the aerogel after the reaction was obtained by scanning. Then the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1), and the concentration of divalent copper ions was calculated to be 10.2 ppm. The detection limit of the copper ion colorimetric detection aerogel test paper was 0.05 ppm, and the linear range was 0.3 to 50 ppm.

[0083] (4) To illustrate the shelf life of the aerogel, a conventional divalent copper ion colorimetric test paper was used for comparison. 3.75 μL of 100 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol was 60%) and 3.75 μL of saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution were mixed and then dropped into the circular unit detection area with a diameter of 3 mm prepared in step (1). After drying, a test paper that can be used for divalent copper ion detection was obtained. 3.75 μL of 10 ppm divalent copper ion standard solution was added to the detection area, and after drying at room temperature, the color intensity after the reaction was obtained by a scanner, and then the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1, except that the copper ion colorimetric detection aerogel test paper was replaced with a conventional divalent copper ion colorimetric detection test paper) to obtain the concentration information of the divalent copper ion. The detection limit of the conventional divalent copper ion colorimetric detection test paper was 1 ppm, and the linear range was 1 to 10 ppm.

[0084] (5) The hydrogel test paper for colorimetric detection of copper ions (referred to as hydrogel), the aerogel test paper for colorimetric detection of copper ions (referred to as aerogel), and the conventional divalent copper ion colorimetric test paper (referred to as conventional paper base) prepared in step (2) are sealed and stored away from light at room temperature, taken out at different time intervals (taken out on the 1st, 7th, 14th, 90th, and 180th days), and the colorimetric signal intensity of the three test papers to a standard test solution with a copper ion concentration of 50 ppm is tested under constant temperature and humidity conditions (20°C, 50RH%).

[0085] The results are as follows Figure 5 and 6 As shown: With the extension of storage time, the conventional divalent copper ion colorimetric test paper has the most obvious colorimetric signal intensity decrease after 90 days ( Figure 5 (a)), the detection ability was basically lost, and the sensitivity of copper ion detection hydrogel also gradually decreased ( Figure 6 ), while the copper ion colorimetric detection aerogel test paper of the present invention remains unchanged and has a longer shelf life ( Figure 5 (b) Figure 6 ).

[0086] Example 6: Detection of divalent copper ions

[0087] (1) Preparation of hydrophilic-hydrophobic patterned semi-enclosed paper substrate: Using screen printing with customized patterns and UV light-curing ink, a circular hydrophilic pattern area with a clear hydrophilic-hydrophobic boundary and a closed bottom was printed on double-circle qualitative filter paper 102#, with a diameter of 2 mm. The specific preparation method is the same as in Example 1.

[0088] (2) Preparation of aerogel test paper for colorimetric detection of copper ions: 1 mL of 100 g / L hydroxylamine hydrochloride glycerol aqueous solution (the volume fraction of glycerol is 60%), 1 mL of acrylamide prepolymer solution (obtained by adding the crosslinking agent N,N-methylenebisacrylamide to the acrylamide glycerol aqueous solution; wherein the mass concentration of acrylamide in the prepolymer solution is 480 g / L, the mass concentration of N,N-methylenebisacrylamide is 10 g / L, and the volume fraction of glycerol in the acrylamide glycerol aqueous solution is 40%) are mixed evenly, and then 100 μL of 5% ammonium persulfate aqueous solution is added, and after shaking evenly, 3.3 μL is taken with a pipette and dropped into the circular unit detection area with a diameter of 2 mm prepared in step (1). Then transfer to a vacuum environment (-1 MPa), react at room temperature for 2 hours, and finally freeze-dry at -20°C for 24 hours to obtain aerogel test paper for colorimetric detection of copper ions.

[0089] (3) Detection of divalent copper ions: 1.65 μL of a 10 ppm divalent copper ion standard solution was added dropwise to a 2 mm circular unit detection area filled with aerogel. After 4 minutes, the color intensity of the aerogel after the reaction was obtained by a scanner. Then, the corresponding copper ion standard curve function was input (the method for obtaining the standard curve function was the same as in Example 1), and the concentration of divalent copper ions was calculated to be 9.9 ppm.

[0090] (4) The copper ion colorimetric detection aerogel test paper was further sealed and stored away from light at room temperature, and taken out after different time intervals (taken out at 1, 7, 30, 90, 180, 365, and 730 days), and the colorimetric signal intensity of the test solution with a copper ion concentration of 50 ppm was tested under constant temperature and humidity conditions (20°C, 50RH%).

[0091] The results are as follows Figure 7 As shown: The detection sensitivity of the copper ion colorimetric detection aerogel test paper can remain basically unchanged after 730 days, indicating that the copper ion colorimetric detection aerogel test paper has a shelf life of up to two years.

[0092] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing an aerogel colorimetric diagnostic test paper with an ultra-long shelf life, characterized in that: The steps include: (1) Preparation of hydrophilic and hydrophobic patterned semi-enclosed paper substrate: A hydrophilic pattern area with a hydrophilic-hydrophobic boundary and a closed bottom is printed on paper by screen printing and ink, and a patterned hydrophilic detection area is obtained after UV curing; (2) Preparation of acrylamide prepolymer solution: Dissolve acrylamide in a glycerol aqueous solution, add a cross-linking agent N,N-methylenebisacrylamide, and stir until a clear and transparent state to obtain an acrylamide prepolymer solution; (3) Preparation of copper ion detection reagent: Dissolving hydroxylamine hydrochloride in glycerol aqueous solution to obtain hydroxylamine hydrochloride glycerol aqueous solution; dissolving 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline in methanol to prepare a saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution; (4) Preparation of aerogel test paper for copper ion colorimetric detection: The acrylamide prepolymer solution obtained in step (2), the hydroxylamine hydrochloride glycerol aqueous solution obtained in step (3) and the saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution are mixed evenly, and then the initiator solution is added and shaken to mix evenly to obtain a gel mixture; the gel mixture is then added dropwise to the patterned hydrophilic detection area obtained in step (1), and then transferred to a vacuum environment for reaction, freeze-dried, and a copper ion colorimetric detection aerogel test paper is obtained, that is, the aerogel colorimetric diagnostic test paper with an ultra-long shelf life.

2. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 1, characterized in that: The freeze-drying temperature in step (4) is -40°C to -20°C; The freeze-drying time in step (4) is 12 to 48 hours.

3. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 1, characterized in that: The hydrophilic-hydrophobic patterned semi-enclosed paper substrate described in step (1) is prepared by a UV curing-screen printing method, and the specific steps are as follows: Use a scraper to print the hydrophobic ink on the paper through a patterned screen. The ink penetrates into the paper to form a hydrophobic area, and the unpenetrated part is the detection area. Then it is dried by UV light to complete the construction of the hydrophilic and hydrophobic boundary on the front side of the paper. Then turn the paper over, and use a scraper to print the hydrophobic ink on the detection area through the screen. The ink will penetrate into the paper downwards, and after drying under UV light, a patterned hydrophilic detection area with a closed bottom will be formed. The conditions for UV light irradiation drying are: wavelength of 300nm, irradiation time of 2 to 10s.

4. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 1, characterized in that: The volume percentage of glycerol in the glycerol aqueous solution described in step (2) is 0% to 80%; The concentration of acrylamide in the acrylamide prepolymer solution in step (2) is 480-960 g / L, and the concentration of N,N-methylenebisacrylamide is 10-20 g / L; The volume percentage of glycerol in the glycerol aqueous solution described in step (3) is 0% to 80%; The concentration of the hydroxylamine hydrochloride glycerol aqueous solution described in step (3) is 80-200 g / L; The volume ratio of the acrylamide prepolymer solution, the hydroxylamine hydrochloride glycerol aqueous solution and the saturated 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline methanol solution described in step (4) is 1:1:

1.

5. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 4, characterized in that: The volume percentage of glycerol in the glycerol aqueous solution described in step (2) is 20-40%; The volume percentage of glycerol in the glycerol aqueous solution described in step (3) is 60% to 80%; The concentration of the hydroxylamine hydrochloride glycerol aqueous solution described in step (3) is 100-200 g / L.

6. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 1, characterized in that: The initiator described in step (4) is at least one of ammonium persulfate, potassium persulfate, azobisisobutyramidine hydrochloride and azobisisobutyronitrile; The concentration of the initiator solution in step (4) is 5% to 20% by mass; The volume ratio of the initiator solution to the acrylamide prepolymer solution in step (4) is 1:5-10.

7. The method for preparing the aerogel colorimetric diagnostic test paper with an ultra-long shelf life according to claim 1, characterized in that: The hydrophobic ink described in step (1) is UV light curing ink or UV light curing wax; The paper in step (1) is office paper, commercial filter paper or hand-made paper; The patterned hydrophilic detection area described in step (1) is a circular patterned hydrophilic detection area with a diameter of 2 to 6 mm; The reaction conditions in step (4) are: reaction at room temperature under vacuum for 1 to 4 hours.

8. An aerogel colorimetric diagnostic test paper with an ultra-long shelf life, characterized in that: It is prepared by the method according to any one of claims 1 to 7.

9. Use of the ultra-long shelf life aerogel colorimetric diagnostic test paper according to claim 8 in detecting divalent copper ions, characterized in that: The application is for non-disease diagnosis purposes.

10. A method for detecting divalent copper ions for non-disease diagnosis purposes, comprising the following steps: (A) at least 5 standard sample solutions with concentration gradients are respectively added dropwise to the detection area of ​​the ultra-long shelf life aerogel colorimetric diagnostic test paper of claim 8 for reaction, dried at room temperature after the reaction, and then the color intensity of the aerogel after the reaction is obtained by a scanner, and then a standard curve is drawn with the concentration of the standard sample solution; wherein, The standard sample solution is a divalent copper ion solution; (B) dropping the sample solution to be tested into the detection area of ​​the ultra-long shelf life aerogel colorimetric diagnostic test paper of claim 8 for reaction, drying at room temperature after the reaction, then obtaining the color intensity of the aerogel after the reaction by a scanner, and then obtaining the concentration or content of the divalent copper ion solution in the sample solution to be tested by drawing a standard curve according to step (A); The reaction time in steps (A) and (B) is 4 to 30 minutes.

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