Indicator composition for water body detection, water body detection method and application

Abstract

The invention provides an indicator composition for water body detection, a water body detection method and application. The indicator composition comprises an indicator and a water-absorbent polymer, the water-absorbing polymer does not react with the indicator. In the invention, the indicator composition does not need to be fixed on the surface of test paper, is used for water body detection, has high accuracy and sensitivity and good repeatability, and also can achieve the purposes of no waste liquid discharge, energy conservation and environmental protection.

Description

Technical Field

[0001] The present invention belongs to the technical field of water body detection, and in particular relates to an indicator composition for water body detection, a water body detection method and an application thereof. Background Art

[0002] Water is an important part of human life and production activities. The quality of water will affect human health, product quality, and equipment life. Therefore, water testing is particularly important in production and life. Water testing involves multiple indicators, such as water color, turbidity, residual chlorine, pH, hardness, chemical oxygen demand, bacteria, etc.

[0003] Most existing detection methods are to fix the indicator on the surface of filter paper to form a test paper, and detect the numerical changes of the corresponding index parameters in the water body by the color change of the test paper. However, for clean water sources such as tap water, swimming pool water, filtered water, etc., it was found during the test process that because the water body is relatively clean, the change range of multiple indicators is small. Taking tap water as an example, its pH changes in the range of 6.5-8.5, the residual chlorine changes in the range of 0-0.5mg / L, and the hardness changes in the range of 0-450mg / L. Such a change range forms a very weak color change on the surface of the test paper with the indicator fixed, resulting in low detection sensitivity. The reason is that the amount of indicator fixed on the test paper as a carrier is very small, and the water absorption capacity of the test paper is limited. The absolute content of the indicator to be tested in the water absorbed per unit area that can react with the test paper is very small, resulting in an unclear color change. In addition, due to the poor light transmittance of the test paper, only the color change of the indicator on the surface of the test paper can be obtained by the naked eye or visual recognition, so that only the color change of part of the indicator in the test paper is observed and used as the basis for reading judgment. Therefore, the sensitivity and accuracy of test paper detection are low.

[0004] Therefore, developing an indicator material that has high detection sensitivity, high accuracy, strong repeatability, and is easy to observe, and can complete the detection without being fixed to the surface of a test paper, is an urgent problem to be solved in this field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention aims to provide an indicator composition for water body detection, a water body detection method and application. The indicator composition does not need to be fixed to the surface of the test paper, is used for water body detection, has high accuracy and sensitivity, strong repeatability, and can also achieve no waste liquid discharge, energy saving and environmental protection.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an indicator composition for water body detection, wherein the indicator composition comprises an indicator and a water-absorbent polymer; the water-absorbent polymer does not react with the indicator.

[0008] In the present invention, the indicator composition does not need to be fixed to the surface of the test paper, is not limited by the thickness and area of ​​the test paper, improves the amount of the indicator, increases the effective content of the indicator that reacts with the water body to be tested, and is beneficial to improving the detection sensitivity and accuracy; and the water-absorbing polymer has a strong water absorption capacity, and can form a gel-like solid when it swells rapidly in water, and stores the water body to be tested inside the gel, thereby increasing the amount and volume of the water body to be tested, thereby increasing the effective content of the water body to be tested that reacts with the indicator, and increasing the contact area between the two, which is beneficial to improving the detection sensitivity and accuracy; in addition, the gel formed by the water-absorbing polymer is colorless and transparent, so that the color can be displayed, and the transparent gel can achieve color superposition, which is more convenient for observation, thereby improving the sensitivity and accuracy; in addition, the indicator composition is used for detection, which has strong repeatability.

[0009] Preferably, the indicator composition comprises 0.1 to 10 parts of indicator and 3.2 to 50 parts of water-absorbing polymer in parts by weight.

[0010] In the present invention, 0.1 to 10 parts of the indicator can be, for example, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, etc.

[0011] In the present invention, 3.2 to 50 parts of the water-absorbing polymer may be, for example, 3.2, 3.5, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, etc.

[0012] In the present invention, the indicator and the water-absorbing polymer are compounded in a specific content, which can more efficiently and sensitively detect the water body; if the content of the indicator is too little, the detection effect is poor, the accuracy and sensitivity are low, and the repeatability is poor; if the content is too much, the solubility is low; if the content of the water-absorbing polymer is too little, the solution to be tested cannot be fully absorbed, and a transparent gel cannot be formed, the detection effect is poor, the accuracy and sensitivity are low, and the repeatability is poor; if the content is too high, material waste is caused.

[0013] Preferably, the water absorption rate of the water-absorbent polymer is 500-8000%, for example, it can be 500%, 600%, 800%, 1000%, 1500%, 2000%, 2500%, 3000%, 3500%, 4000%, 4500%, 5000%, 5500%, 6000%, 6500%, 7000%, 7500%, 8000% and the like.

[0014] In the present invention, the water absorption rate refers to the weight percentage of the water absorption increase of the material under normal atmospheric pressure; the water absorption rate is within the above range, which can ensure that the water-absorbing polymer fully absorbs the water to be tested and forms a transparent gel-like substance, and under the condition of uniform premixing, the indicator will fully contact with the water to be tested and uniformly color inside the gel, thereby facilitating subsequent color discrimination.

[0015] Preferably, the water-absorbing polymer includes any one of polyacrylic acid, cellulose, polyacrylonitrile, polyvinyl alcohol or alginic acid, or a combination of at least two of them, more preferably cellulose and / or alginic acid.

[0016] In the present invention, the water-absorbing polymer does not undergo any chemical reaction with the indicator, thereby not affecting the response of the indicator to be measured in the water body to be measured; the water-absorbing polymer has extremely high water absorption and can instantly absorb water and form a uniform solid substance; the water-absorbing polymer is colorless and transparent after absorbing water and can show the color of the indicator.

[0017] Preferably, the cellulosics include cellulose and / or cellulose derivatives.

[0018] Preferably, the cellulose derivative includes any one of sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose or hydroxybutyl methyl cellulose, or a combination of at least two thereof.

[0019] Preferably, the alginic acid comprises any one of sodium alginate, potassium alginate, ammonium alginate, magnesium alginate or propylene glycol alginate, or a combination of at least two thereof.

[0020] In the present invention, sodium alginate will not affect the residual chlorine concentration, and thus will not interfere with the determination; therefore, when performing residual chlorine detection, the preferred water-absorbing polymer is sodium alginate.

[0021] Preferably, the water-absorbent polymer includes alginic acid and cellulose, and the mass ratio of alginic acid to cellulose is 100:(0.01-115), wherein the specific value in (0.01-115) can be, for example, 0.01, 0.05, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, etc.

[0022] In the present invention, cellulose and alginic acid are compounded in a specific ratio, which is beneficial to improving the stability of the gel during the detection process, thereby improving the detection sensitivity, accuracy and repeatability.

[0023] Preferably, the viscosity of the alginic acid is 200-550mPa.s, for example, it can be 200mPa.s, 210mPa.s, 220mPa.s, 230mPa.s, 240mPa.s, 250mPa.s, 260mPa.s, 270mPa.s, 280mPa.s, 300mPa.s, 320mPa.s, 340mPa.s, 360mPa.s, 380mPa.s, 400mPa.s, 420mPa.s, 440mPa.s, 460mPa.s, 480mPa.s, 500mPa.s, 520mPa.s, 540mPa.s, 550mPa.s, etc.

[0024] Preferably, the viscosity of the cellulose is 50 to 800 mPa.s, for example, 50 mPa.s, 60 mPa.s, 80 mPa.s, 100 mPa.s, 120 mPa.s, 140 mPa.s, 160 mPa.s, 180 mPa.s, 200 mPa.s, 210 mPa.s, 220 mPa.s, 230 mPa.s, 240 mPa.s, 250 mPa.s, 260 mPa.s, 270 mPa.s, 280 mPa.s, 300 mPa.s, 320 mPa.s, 340 mPa.s, 360mPa.s, 380mPa.s, 400mPa.s, 420mPa.s, 440mPa.s, 460mPa.s, 480mPa.s, 500mPa.s, 520mPa.s, 540mPa.s, 550mPa.s, 560mP a.s, 580mPa.s, 600mPa.s, 620mPa.s, 640mPa.s, 660mPa.s, 680mPa.s, 700mPa.s, 720mPa.s, 740mPa.s, 780mPa.s, 800mPa.s, etc.

[0025] In the present invention, the cellulose preferably includes cellulose A or cellulose B; the viscosity of the cellulose A is 50-200 mPa.s, and the mass ratio of the alginic acid to the cellulose is 100:(0.01-115); the viscosity of the cellulose B is 300-800 mPa.s, and the mass ratio of the alginic acid to the cellulose is 100:(0.01-78).

[0026] Preferably, the indicator composition further comprises a metal salt.

[0027] Preferably, the mass ratio of the water-absorbing polymer to the metal salt is 100:(0.5-9), wherein the specific value of (0.5-9) can be, for example, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, 5.2, 5.5, 5.8, 6, 6.2, 6.5, 6.8, 7, 7.2, 7.5, 7.8, 8, 8.2, 8.5, 8.8, 9, etc.

[0028] Preferably, the metal salt comprises anhydrous calcium chloride and / or anhydrous magnesium chloride.

[0029] In the present invention, by adding a specific amount of metal salt, it can be used as an accelerator to assist in the rapid formation of a uniform and stable gel.

[0030] Preferably, the indicator includes at least one of a residual chlorine indicator, a pH indicator or a hardness indicator.

[0031] In the present invention, the indicator is not limited to the above-mentioned indicators, and can be replaced with corresponding indicators according to the detection index.

[0032] Preferably, the residual chlorine indicator comprises an aniline reducing indicator.

[0033] In the present invention, the aniline reducing indicator includes but is not limited to N,N-diethyl-1,4-phenylenediamine, 3,3',5,5'-tetramethylbenzidine, dimethylaminobenzidine and the like.

[0034] In the present invention, the pH indicator includes but is not limited to thymol blue, methyl yellow, methyl orange, bromophenol blue, bromocresol green, methyl red, bromothymol blue, neutral red, phenol red, phenolphthalein, thymolphthalein, etc.; it can be specifically selected according to the detection range.

[0035] In the present invention, the indicator of water hardness includes but is not limited to chrome black-T, naphthol green, calcium red and the like.

[0036] Preferably, the indicator composition also includes 0.001 to 10 parts of other auxiliary agents, for example, 0.001, 0.005, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, etc.

[0037] Preferably, the other auxiliary agents include at least one of a buffer, a co-solvent, an auxiliary color developer, a redox protective agent or an ionic strength regulator.

[0038] In the present invention, suitable additives can be added according to actual needs.

[0039] In the present invention, the preparation method of the indicator composition comprises: mixing the indicator with the water-absorbing polymer, and grinding them uniformly to obtain the indicator composition.

[0040] In the present invention, the mixed materials also include metal salts and / or other additives.

[0041] In the present invention, when other auxiliary agents are included, the preparation method comprises premixing the indicator with the other auxiliary agents to obtain indicator powder; and then mixing the indicator powder with the water-absorbent polymer.

[0042] In a second aspect, the present invention provides a water body detection method, the water body detection method comprising the following steps:

[0043] At least one cavity is set on the surface of the substrate, and the indicator composition described in the first aspect is placed in the cavity, and the surface of the cavity is covered with a water-soluble film; then the liquid to be tested is added to the cavity through the water-soluble film, and the indicator composition forms a gel, and the color change and distribution in the gel are observed and compared with the standard color card, so as to obtain the specific value of the indicator to be tested.

[0044] In the present invention, the four walls of the cavity are perpendicular to the bottom surface, and the bottom surface is horizontal.

[0045] In the present invention, the volume of the indicator composition is less than the volume of the cavity.

[0046] In the present invention, the volume of the indicator composition refers to the volume of the substance formed when placed in the cavity.

[0047] Preferably, before placing the indicator composition in the cavity, the method further comprises placing a pre-gel in the cavity.

[0048] Preferably, the pregel is prepared from water and a water-absorbent polymer; the mass ratio of water to the water-absorbent polymer is (0.5-4.5):1, wherein the specific value in (0.5-4.5) can be, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.5, etc.

[0049] Preferably, the mass ratio of the pregel to the indicator composition is (1.5-800):1, wherein the specific value in (1.5-800) can be, for example, 1.5, 2, 4, 6, 8, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, etc.

[0050] In the present invention, by placing the pre-gel in the cavity in advance, it is beneficial for the indicator composition to quickly form a gel after contacting with water.

[0051] In the present invention, the water-soluble film can be selected from films that do not chemically react with any component in the test liquid and dissolve quickly in water, including but not limited to glutinous rice paper.

[0052] In the present invention, the content of the liquid to be tested added to the cavity does not exceed the maximum content that the indicator composition can absorb.

[0053] In the present invention, during detection, the liquid to be tested is dripped onto the surface of the water-soluble film, and the liquid to be tested dissolves the water-soluble film and then penetrates into the cavity, so that the water-absorbent polymer in the cavity quickly absorbs water to expand and form a gel. At the same time, the indicator contained in the indicator powder reacts with the corresponding substance in the liquid to be tested to develop color, and the color will be distributed in the gel, so that the color change and distribution can be observed and compared with the standard color card, and the specific value of the corresponding detection index of the liquid to be tested can be read.

[0054] Preferably, the method of observing the color change and distribution in the gel comprises visual observation and / or observation by a photodiode.

[0055] In the present invention, the visual observation includes observation with the naked eye or visual recognition using a camera.

[0056] In the present invention, the method of observing by means of a photodiode includes a transmission method and / or a reflection method.

[0057] In the present invention, through observation by a photodiode, the color can be identified by the reflectivity of the gel for light of different wavelengths, or by the transmittance or absorbance of the gel at a certain wavelength.

[0058] In the present invention, the transmission method is adopted for detection, and the photodiode and the corresponding illumination light source are located on both sides of the cavity; that is, the positional relationship between the photodiode, the corresponding illumination light source and the cavity is the photodiode, the cavity and the corresponding illumination light source placed in sequence; the photodiode and the corresponding illumination light source can be located on the front and back sides, left and right sides or upper and lower sides of the cavity.

[0059] In the present invention, the reflection method is used for detection, and the photodiode should be located on the same side of the cavity as the corresponding illumination light source; that is, the photodiode should be located on the upper side, lower side, front side, rear side, left side or right side of the cavity as the corresponding illumination light source.

[0060] Preferably, the visual observation or the detection by the reflection method has a thickness of the cavity ≤ 10 mm, for example, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.

[0061] Preferably, the transmission method is used for detection, and the thickness of the cavity is ≤50 mm, for example, it can be 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc.

[0062] In the present invention, a suitable cavity size can be selected according to actual needs; a cavity with a small bottom area and a large thickness is preferred; because the gel has a certain degree of transparency, when observed from above the gel, the saturation of the gel color will be enhanced as the thickness of the gel layer increases. The thickness of the gel layer is related to the total water absorption capacity of the indicator composition and the bottom area of ​​the cavity. The more total water absorption of the composition and the smaller the bottom area of ​​the cavity, the thicker the gel layer thickness formed, the higher the color saturation, and the better the detection sensitivity for the detection index in an extremely low range.

[0063] In the present invention, based on the observation method, when the color is identified by the reflection ability of the gel for light of different wavelengths, affected by the penetration and reflection ability of light, the thickness of the gel cavity does not need to exceed 10 mm. The excess part requires additional addition of absorbent polymer high molecular material and its corresponding amount of indicator and other additives, which causes waste; and when the transmittance or absorbance at a certain wavelength is used for identification, the thickness of the gel cavity is as large as possible, and the maximum should not exceed 50 mm. After exceeding the thickness, due to the decrease in transmittance and the background noise interference of electronic components, the accuracy of the detection result shows a reverse downward trend.

[0064] In the detection method provided by the present invention, compared with the conventional detection test paper with a thickness of about 0.5 mm (the indicator holding amount per unit area is about 2×10 -10 mol, the water absorption per unit area is 0.4μL), the indicator retention is significantly increased. Taking the actual cavity of 5mm*5mm*10mm as an example, the indicator content can be increased to 2×10 -9 -2×10 -8 mol; water absorption capacity is significantly enhanced, unit area (mm 2 ) The water absorption can reach 0.2-2μL / mm×the thickness of the gel layer after absorption.

[0065] In a third aspect, the present invention provides an application of the indicator composition according to the first aspect or the water body detection method according to the second aspect in detecting residual chlorine in water.

[0066] In the present invention, the concentration of residual chlorine detection is ≤10 mg / L, and has better resolution for low concentration residual chlorine (≤1 mg / L).

[0067] Preferably, the detection temperature of the residual chlorine is 0-40°C.

[0068] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] The indicator composition provided by the present invention is compounded with an indicator and a water-absorbing polymer. After absorbing a liquid to be tested, the water-absorbing polymer forms a gel, so that the indicator and the liquid to be tested complete a color development reaction in the gel, thereby realizing detection of corresponding indicators of the liquid to be tested. The indicator composition does not need to be fixed to the surface of a test paper, has a high indicator retention amount, strong water absorption capacity, and is easy to observe. It is used for water body detection, improves the sensitivity, accuracy and repeatability of water body detection, and does not discharge waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 It is a schematic diagram of the detection device described in Application Example 1 of the present invention;

[0072] Wherein: 1-substrate; 2-cavity containing indicator composition;

[0073] Figure 2 It is a schematic diagram of the composition of the cavity containing the indicator composition of the detection device described in Application Example 1 of the present invention;

[0074] Wherein: 21-water-soluble film; 22-indicator composition; 23-cavity. DETAILED DESCRIPTION

[0075] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0076] Example 1

[0077] This embodiment provides an indicator composition, which includes 5 parts of an indicator and 25 parts of a water-absorbent polymer, in parts by weight; the indicator is a residual chlorine indicator (N,N-diethyl-1,4-phenylenediamine); the water-absorbent polymer includes sodium alginate (viscosity of 350 mPa.s) and sodium carboxymethyl cellulose (viscosity of 400 mPa.s) in a mass ratio of 100:40; the indicator composition also includes anhydrous calcium chloride; the mass ratio of the water-absorbent polymer to the anhydrous calcium chloride is 100:5.

[0078] This embodiment provides a method for preparing the indicator composition, which specifically comprises the following steps:

[0079] The water-absorbing polymer and anhydrous calcium chloride are mixed, ground for 30 minutes, and then an indicator is added and ground for 1 minute in the dark to obtain the indicator composition.

[0080] Example 2

[0081] This embodiment provides an indicator composition, which includes 2 parts of an indicator and 8 parts of a water-absorbing polymer, in parts by weight; the indicator is a residual chlorine indicator (3,3',5,5'-tetramethylbenzidine); the water-absorbing polymer includes sodium alginate (viscosity of 420 mPa.s) and sodium carboxymethyl cellulose (viscosity of 600 mPa.s) in a mass ratio of 100:30; the indicator composition also includes anhydrous calcium chloride; the mass ratio of the water-absorbing polymer to anhydrous magnesium chloride is 100:2.

[0082] This embodiment provides a method for preparing the indicator composition, and the specific steps are the same as those in Embodiment 1.

[0083] Example 3

[0084] This embodiment provides an indicator composition, which includes 8 parts of an indicator and 45 parts of a water-absorbent polymer, in parts by weight; the indicator is a residual chlorine indicator (3,3',5,5'-tetramethylbenzidine); the water-absorbent polymer includes sodium alginate (viscosity of 540 mPa.s) and sodium carboxymethyl cellulose (viscosity of 150 mPa.s) in a mass ratio of 100:50; the indicator composition also includes anhydrous calcium chloride; the mass ratio of the water-absorbent polymer to the anhydrous calcium chloride is 100:8.

[0085] This embodiment provides a method for preparing the indicator composition, and the specific steps are the same as those in Embodiment 1.

[0086] Example 4

[0087] This embodiment provides an indicator composition, which is different from Example 3 only in that the total mass of sodium alginate and sodium carboxymethyl cellulose remains unchanged, the mass ratio is 100:10, and the other components, amounts and preparation methods are the same as those in Example 3.

[0088] Example 5

[0089] This embodiment provides an indicator composition, which is different from Example 3 only in that the total mass of sodium alginate and sodium carboxymethyl cellulose remains unchanged, the mass ratio is 100:90, and the other components, amounts and preparation methods are the same as those in Example 3.

[0090] Example 6

[0091] This embodiment provides an indicator composition, which is different from the embodiment 3 only in that the viscosity of the sodium alginate is 300 mPa.s, and the other components, dosages and preparation methods are the same as those in the embodiment 3.

[0092] Example 7

[0093] This embodiment provides an indicator composition, which is different from the embodiment 3 only in that the viscosity of sodium alginate is 657 mPa.s (Jiangsu Caiwei Biotechnology Co., Ltd.), and the other components, dosages and preparation methods are the same as those in the embodiment 3.

[0094] Example 8

[0095] This embodiment provides an indicator composition, which differs from the embodiment 3 only in that sodium alginate is replaced with polyvinyl alcohol of the same mass, and the other components, dosages and preparation methods are the same as those in the embodiment 3.

[0096] Example 9

[0097] This embodiment provides an indicator composition, which differs from the embodiment 3 only in that sodium alginate is replaced with starch of equal mass, and other components, dosages and preparation methods are the same as those in the embodiment 3.

[0098] Example 10

[0099] This embodiment provides an indicator composition, which differs from Embodiment 3 only in that the content of anhydrous calcium chloride is reduced so that the mass ratio of the water-absorbing polymer to anhydrous calcium chloride is 100:0.2, and the other components, amounts and preparation methods are the same as those in Embodiment 3.

[0100] Embodiment 11

[0101] This embodiment provides an indicator composition, which differs from Embodiment 3 only in that the content of anhydrous calcium chloride is increased so that the mass ratio of the water-absorbing polymer to anhydrous calcium chloride is 100:12, and the other components, dosages and preparation methods are the same as those in Embodiment 3.

[0102] Example 12

[0103] This embodiment provides an indicator composition, which is different from the embodiment 3 only in that the total mass of the water-absorbing polymer remains unchanged, sodium carboxymethyl cellulose is not included, and other components, amounts and preparation methods are the same as those in the embodiment 3.

[0104] Embodiment 13

[0105] This embodiment provides an indicator composition, which is different from the embodiment 3 only in that the indicator composition does not contain anhydrous calcium chloride, and the other components, dosages and preparation methods are the same as those of the embodiment 3.

[0106] Embodiment 14

[0107] This embodiment provides an indicator composition, which is different from Example 3 only in that the indicator composition does not contain anhydrous calcium chloride, the total mass of the water-absorbing polymer remains unchanged, and there is no sodium carboxymethyl cellulose. Other components, amounts, and preparation methods are the same as those in Example 3.

[0108] Application Example 1

[0109] This application example provides a method for detecting residual chlorine in water, and the detection method comprises the following steps:

[0110] At least one cavity is set on the surface of a polyethylene terephthalate (PET) substrate, the four walls of the cavity are perpendicular to the bottom surface, the bottom surface is horizontal, and the cavity size is 5 mm × 5 mm × 10 mm in length × width × height, then the indicator composition (the indicator composition provided in Example 1) is placed in the cavity, and the surface is covered with glutinous rice paper to obtain the following: Figure 1 The detection device of the structure shown in the figure comprises a substrate 1 and a cavity 2 containing an indicator composition; the composition of the cavity 2 containing the indicator composition is as follows Figure 2As shown, it includes a water-soluble film 21, an indicator composition 22 and a cavity 23; then 0.2 mL of the liquid to be tested (the liquid to be tested is a tap water sample, which spontaneously enters the sample collection pool through pressure and is accurately added by a pipette) is dropped onto the surface of the glutinous rice paper, and the liquid to be tested dissolves the glutinous rice paper and penetrates into the cavity, the water-absorbent polymer quickly absorbs water and expands, and at the same time, the indicator contained in the composition reacts with the corresponding substance in the liquid to be tested to develop color, and the color is distributed in the gel formed by the water-absorbent polymer, and the camera identifies its RGB color components and compares them with the standard card, thereby obtaining the residual chlorine content in the liquid to be tested.

[0111] Application Examples 2 to 14

[0112] Application Examples 2 to 14 respectively provide a method for detecting residual chlorine in water, which differs from Application Example 1 only in that, in the preparation method, the indicator composition provided in Example 1 is replaced by an indicator composition of equal mass provided in Examples 2 to 14, and the other steps are the same as those in Application Example 1.

[0113] Application Example 15

[0114] This application example provides a method for detecting residual chlorine in water, which differs from Application Example 1 only in that, in the detection method, before placing the indicator composition in the cavity, water and sodium alginate in a mass ratio of 3:1 are pre-added in the cavity to form a pregel, and then the indicator composition is placed. The mass ratio of the pregel to the indicator composition is 5:1; the other steps are the same as those in Application Example 1.

[0115] Application Example 16

[0116] This application example provides a method for detecting residual chlorine in water. The only difference between this method and application example 1 is that, in the detection method, camera recognition is replaced by photodiode observation, a photodiode and a corresponding light source are arranged above the cavity, and the reflective ability of the gel in the cavity for light of different wavelengths is measured to identify the color. The other steps are the same as those in application example 1.

[0117] Performance Testing

[0118] The residual chlorine content obtained by the detection method for residual chlorine in the water provided by the present invention is compared with the residual chlorine content obtained by the national standard DPD (N, N-diethyl-p-phenylenediamine) colorimetric method, and the difference between the two is calculated. The smaller the absolute value of the difference, the higher the accuracy of the detection method provided by the present invention; and the standard deviation of the residual chlorine content is calculated. The smaller the standard deviation, the stronger the repeatability of the detection method provided by the present invention. In addition, the gel color development time in the detection method provided by the present invention is observed and recorded. The shorter the color development time, the higher the sensitivity.

[0119] Among them, the method of using DPD colorimetric method to test the residual chlorine content in water according to national standard GB5749 includes: taking 10mL of water sample, adding phosphate buffer and appropriate amount of DPD powder, shaking well and measuring the absorbance at 515nm by spectrophotometry within 30s. The absorbance is compared with the absorbance curve of the standard residual chlorine solution to obtain the residual chlorine concentration of the water sample at this time. According to the required residual chlorine range, a typical measurement concentration such as 0.1mg / L, 0.2mg / L, 0.5mg / L, 0.8mg / L, 1mg / L, etc. is selected, and the solution is prepared and the true value of the residual chlorine of the prepared solution is measured and recorded using the national standard method.

[0120] The prepared solution was tested according to the method provided in the application example of the present invention to obtain the test results, and the test was conducted 6 times in parallel; the test results were compared with the true value of residual chlorine determined by the national standard method, and the accuracy and standard deviation of the 6 test results were calculated.

[0121] The specific test results are shown in Table 1:

[0122] Table 1

[0123] Accuracy Standard Deviation Reaction time Application Example 1 ±0.05ppm 0.028 30s Application Example 2 ±0.07ppm 0.043 30s Application Example 3 ±0.08ppm 0.045 30s Application Example 4 ±0.13ppm 0.089 30s Application Example 5 ±0.11ppm 0.078 30s Application Example 6 ±0.11ppm 0.094 30s Application Example 7 ±0.2ppm 0.128 45s Application Example 8 ±0.17ppm 0.101 30s Application Example 9 ±0.31ppm 0.288 30s Application Example 10 ±0.10ppm 0.066 40s Application Example 11 ±0.11ppm 0.054 20s Application Example 12 ±0.29ppm 0.143 30s Application Example 13 ±0.14ppm 0.075 45s Application Example 14 ±0.38ppm 0.301 45s Application Example 15 ±0.03ppm 0.011 15s Application Example 16 ±0.04ppm 0.017 30s

[0124] As can be seen from Table 1, the indicator composition provided by the present invention does not need to be fixed on the surface of the test paper, but forms a gel after absorbing the liquid to be tested, and the indicator and the liquid to be tested complete a color reaction in the gel, thereby realizing the detection of the index to be tested in the water body, and the detection accuracy is high, the repeatability is good, the color development time is short, and the sensitivity is high; taking the detection of residual chlorine in the water body as an example, the indicator composition provided by the present invention is used for detection, and the accuracy is ≤0.38ppm, the standard deviation is ≤0.301, the repeatability is good, and the reaction time is ≤45s, the color development is fast, and the sensitivity is high. In some embodiments, the detection accuracy of the detection method provided by the present invention can be as low as 0.2ppm, and can even reach below 0.08ppm, and the accuracy is extremely high; the standard deviation can reach below 0.2, or even below 0.094, and the repeatability is extremely good; the reaction time can also be ≤30s.

[0125] By comparing Application Examples 1, 2, 3 with Application Examples 4-14, it can be seen that the water-absorbing polymer adopts a specific composition, and the indicator composition also includes a metal salt, which can further improve the detection effect, with higher detection accuracy and stronger repeatability, among which Application Example 1 has the best effect.

[0126] As can be seen from Application Example 15, when the water-absorbent polymer is mixed with water in advance to form a pre-gel and then added to the cavity first, a uniform gel will be formed, which is conducive to shortening the reaction time and developing color quickly. The test results are similar to those in Application Example 1 and do not affect the test results. As can be seen from Application Example 16, the use of a photodiode for observation can directly replace the human eye for color card analysis, and the test results are similar to those in Application Example 1.

[0127] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. An indicator composition for water body detection, characterized in that: The indicator composition comprises an indicator and a water-absorbing polymer; The water-absorbing polymer does not react with the indicator.

2. The indicator composition according to claim 1, characterized in that In parts by weight, the indicator composition comprises 0.1 to 10 parts of an indicator and 3.2 to 50 parts of a water-absorbing polymer.

3. The indicator composition according to claim 1, characterized in that The water absorption rate of the water-absorbing polymer is 500 to 8000%.

4. The indicator composition according to claim 1, characterized in that The water-absorbing polymer includes any one of polyacrylic acid, cellulose, polyacrylonitrile, polyvinyl alcohol or alginic acid, or a combination of at least two of them.

5. The indicator composition according to claim 4, characterized in that The celluloses include cellulose and / or cellulose derivatives.

6. The indicator composition according to claim 5, characterized in that The cellulose derivative includes any one of sodium carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose or hydroxybutyl methyl cellulose, or a combination of at least two thereof.

7. The indicator composition according to claim 4, characterized in that The alginic acid comprises any one of sodium alginate, potassium alginate, ammonium alginate, magnesium alginate or propylene glycol alginate, or a combination of at least two thereof.

8. The indicator composition according to claim 4, characterized in that The water-absorbing polymer includes cellulose and alginic acid, and the mass ratio of the alginic acid to the cellulose is 100:(0.01-115).

9. The indicator composition according to claim 8, characterized in that The viscosity of the alginic acid is 200-550 mPa.s; The viscosity of the cellulose is 50 to 800 mPa.s.

10. The indicator composition according to claim 1, characterized in that The indicator composition also includes a metal salt.

11. The indicator composition according to claim 10, characterized in that The mass ratio of the water-absorbing polymer to the metal salt is 100:(0.5-9).

12. The indicator composition according to claim 10, characterized in that The metal salt includes anhydrous calcium chloride and / or anhydrous magnesium chloride.

13. The indicator composition according to claim 1, characterized in that The indicator includes at least one of a residual chlorine indicator, a pH indicator or a hardness indicator; The residual chlorine indicator comprises an aniline reducing indicator.

14. The indicator composition according to claim 1, characterized in that The indicator composition also includes 0.001 to 10 parts of other auxiliary agents; The other auxiliary agents include at least one of a buffer, a co-solvent, an auxiliary color developer, a redox protective agent or an ionic strength regulator.

15. A water body detection method, characterized in that: The water body detection method comprises the following steps: At least one cavity is arranged on the surface of the substrate, and the indicator composition according to any one of claims 1 to 14 is placed in the cavity, and the surface of the cavity is covered with a water-soluble film; then the liquid to be tested is added to the cavity through the water-soluble film, and the indicator composition forms a gel, and the color change and distribution in the gel are observed and compared with the standard color card, so as to obtain the specific value of the indicator to be tested.

16. The water body detection method according to claim 15, characterized in that: The volume of the indicator composition is less than the volume of the cavity.

17. The water body detection method according to claim 15, characterized in that: Prior to placing the indicator composition in the cavity, the method further includes placing a pre-gel in the cavity; The pregel is prepared from water and a water-absorbent polymer; the mass ratio of water to the water-absorbent polymer is (0.5-4.5):1; The mass ratio of the pregel to the indicator composition is (1.5-800):

1.

18. The water body detection method according to claim 15, characterized in that: The method of observing the color change and distribution in the gel includes visual observation and / or observation by a photodiode; The method of observing by means of a photodiode includes a transmission method and / or a reflection method; The transmission method is used for detection, and the photodiode and the corresponding illumination light source are located on both sides of the cavity; When the reflection method is used for detection, the photodiode and the corresponding illumination light source should be located on the same side of the cavity.

19. The water body detection method according to claim 18, characterized in that: The thickness of the cavity is ≤10mm when the visual observation or the reflection method is used for detection; The transmission method is used for detection, and the thickness of the cavity is ≤50mm.

20. Use of the indicator composition according to any one of claims 1 to 14 or the water body detection method according to any one of claims 15 to 19 in detecting residual chlorine in water.

21. The use according to claim 20, characterized in that The concentration of the residual chlorine detection is ≤10mg / L; The detection temperature of the residual chlorine is 0-40°C.

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