Concentration determining member, method for manufacturing the concentration determining member, and method for determining the concentration of hypochlorous acid

Abstract

A concentration determining element that can easily determine the concentration of hypochlorous acid in a test liquid, a method for manufacturing the concentration determining element, and a method for determining the concentration of hypochlorous acid are provided. [Solution] The concentration determining member of the present invention is a concentration determining member comprising a measurement substrate and a colored pattern provided on the surface of the measurement substrate, and is characterized in that the colored pattern contains an organic coating having a cationic group and an anionic dye.

Description

[Technical Field]

[0001] The present invention relates to a concentration determining member, a method for manufacturing a concentration determining member, and a method for determining the concentration of hypochlorous acid. [Background technology]

[0002] Currently, test papers are commercially available as analytical strips for measuring the concentration of various analytes, but they often have poor visibility due to their monotonous and lacking color change. For example, known test papers for measuring hypochlorous acid concentration use a direct reaction between a dye and hypochlorous acid or a direct method that utilizes a pH change caused by hypochlorous acid as the reaction principle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6871663 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional test papers for measuring hypochlorous acid concentration can only use specific dyes that react and change color. This limits the color options and the response color change. While there are concerns about the toxicity and durability of the dyes, synthesizing new dyes requires a great deal of effort, time, and complicated synthesis procedures.

[0005] Therefore, an object of the present invention is to provide a concentration determining element that can easily determine the concentration of hypochlorous acid in a test liquid based on a change in color tone, a method for manufacturing the concentration determining element, and a method for determining the concentration of hypochlorous acid. [Means for solving the problem]

[0006] In order to achieve the above object, the inventors have conducted extensive research and have found that by providing a colored pattern including an organic coating having a predetermined organic group and a dye, it is possible to obtain a concentration-determining element that can easily determine the concentration of hypochlorous acid, a method for manufacturing the concentration-determining element, and a method for determining the concentration of hypochlorous acid in a test liquid.

[0007] That is, the present invention is a concentration determining member comprising a measurement substrate and a colored pattern provided on the surface of the measurement substrate, wherein the colored pattern contains an organic coating having a cationic group and an anionic dye.

[0008] The present invention also provides a method for producing the aforementioned concentration-determining member, which comprises impregnating a measurement substrate with a raw material aqueous solution containing a polymer having a cationic group and an anionic dye, and drying the measurement substrate impregnated with the raw material aqueous solution to form a colored pattern containing an organic coating having a cationic group and an anionic dye.

[0009] Furthermore, the present invention provides a method for manufacturing the aforementioned concentration-determining member, which comprises forming an organic coating containing a polymer having cationic groups on a measurement substrate, and stencil printing a dye aqueous solution containing the anionic dye onto the surface of the organic coating to form a colored pattern containing the organic coating having cationic groups and the anionic dye.

[0010] Furthermore, the present invention provides a method for producing the aforementioned concentration-determining member, which comprises forming an organic coating containing a polymer having cationic groups on a measurement substrate, and ink-jet printing a dye aqueous solution containing the anionic dye in a predetermined shape on the surface of the organic coating, thereby forming a colored pattern containing the organic coating having cationic groups and the anionic dye.

[0011] Furthermore, the present invention is a method for determining the concentration of hypochlorous acid using the above-mentioned concentration determining member, which involves contacting a test liquid with the colored pattern, and if the colored pattern does not change after 1 to 10 minutes, determining that no hypochlorous acid is present in the test liquid. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a concentration determining member that can easily determine the concentration of hypochlorous acid in a test liquid, a method for manufacturing the concentration determining member, and a method for determining the concentration of hypochlorous acid. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a graph showing changes in absorbance of colored pattern 1. [Figure 2] FIG. 10 is a graph showing changes in absorbance of colored pattern 2. [Figure 3] FIG. 10 is a graph showing changes in absorbance of colored pattern 3. [Figure 4] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 1 minute. [Figure 5] FIG. 10 shows a comparison between coloring patterns of absorbance changes after an immersion time of 3 minutes. [Figure 6] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 10 minutes. [Figure 7] FIG. 10 shows a comparison of the absorbance change between colored patterns. [Figure 8] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 1 minute. [Figure 9] FIG. 10 shows a comparison between coloring patterns of absorbance changes after an immersion time of 3 minutes. [Figure 10] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 10 minutes. [Figure 11] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 1 minute. [Figure 12] FIG. 10 shows a comparison between coloring patterns of absorbance changes after an immersion time of 3 minutes. [Figure 13] FIG. 10 shows a comparison between coloring patterns of absorbance changes after immersion for 10 minutes. [Figure 14] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 1 minute. [Figure 15] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 3 minutes. [Figure 16] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 3 minutes. [Figure 17] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 10 minutes. [Figure 18] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 10 minutes. [Figure 19] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 1 minute. [Figure 20] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 3 minutes. [Figure 21] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 10 minutes. [Figure 22] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 1 minute. [Figure 23] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 3 minutes. [Figure 24] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength when a stencil-printed sample is immersed for 10 minutes. [Figure 25] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength for an inkjet print sample after immersion for 1 minute. [Figure 26] FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength for an inkjet print sample after an immersion time of 3 minutes. [Figure 27]FIG. 10 is a graph showing the rate of change in absorbance at the maximum absorption wavelength for an inkjet print sample after immersion for 10 minutes. DETAILED DESCRIPTION OF THE INVENTION

[0014] The concentration determining member, the method for manufacturing the concentration determining member, and the method for determining the concentration of hypochlorous acid of the present invention will be described in detail below. The concentration determining member of the present invention comprises a measurement substrate and a colored pattern coated on the surface of the measurement substrate. The measurement substrate may be made of, for example, a glass plate, an acrylic plate, a PET plate, or various types of filter paper. The size of the measurement substrate is not particularly limited and can be selected appropriately, but considering ease of handling, it is preferably about 3 cm x 3 cm.

[0015] The surface of the measurement substrate is provided with a colored pattern containing an organic coating having cationic groups and an anionic dye. This colored pattern remains unchanged when not in contact with hypochlorous acid, but tends to fade when in contact with hypochlorous acid. Examples of cationic groups include quaternary ammonium groups, tertiary ammonium groups, and primary ammonium groups, with quaternary ammonium groups being particularly preferred.

[0016] Examples of anionic dyes include Fast Green FCF (FG), Acid Red 18 (AR18), Sunset Yellow FCF (SY), Acid Red 27 (AR27), Brilliant Blue FCF (BB), Indigo Calamine (Indigo), Acid Red 112, Acid Red 114, Direct Yellow 50, indigotetrasulfonic acid, and chrysophenine.

[0017] The organic coating may further contain a boronic acid group. Examples of the boronic acid group include a phenylboronic acid group and an alkylboronic acid group, with a phenylboronic acid group being particularly preferred. When a boronic acid group is present in the organic coating, it becomes possible to control the response sensitivity. The hypochlorous acid concentration and reaction time at which decolorization occurs can be controlled. This will be explained in detail later.

[0018] The colored pattern in the present invention can be formed on the surface of the measurement substrate by various methods using a monomer having a cationic group, specifically, photopolymerization, dip coating, stencil printing, and inkjet printing. Each of the forming methods will be described below.

[0019] (Photopolymerization method) First, a monomer solution is prepared by dissolving a monomer having a cationic group, a crosslinking agent, and a polymerization initiator in a predetermined solvent. An example of the monomer having a cationic group is (3-acrylamidopropyl)trimethylammonium chloride. The monomer solution can be prepared, for example, by dissolving 10 to 100 mmol / L of (3-acrylamidopropyl)trimethylammonium chloride, 500 to 1000 mmol / L of dimethylacrylamide, 50 to 200 mmol / L of a crosslinking agent, and 20 to 100 mmol / L of a polymerization initiator in a solvent.

[0020] The crosslinking agent can be selected from methylene bisacrylamide, ethylene glycol dimethacrylate, etc. The polymerization initiator can be selected from 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-methyl-N-(2-hydroxymethyl)propionamide], etc.

[0021] As a solvent for preparing the monomer solution, for example, a mixture of dimethyl sulfoxide (DMSO) and water (volume ratio 1:1) can be used. In this case, distilled water, ion-exchanged water, etc. can be used as the water. Dimethylformamide, methanol, etc. can also be used as the solvent for the monomer solution.

[0022] To form an organic coating further containing a boronic acid group, the monomer solution contains a monomer containing a boronic acid group. Examples of the monomer containing a boronic acid group include 3-acrylamidophenylboronic acid and 4-vinylphenylboronic acid. It is desirable to further use (3-acrylamidopropyl)trimethylammonium chloride, N,N-dimethylacrylamide, etc. as the monomer in the first monomer solution.

[0023] For example, a monomer solution can be prepared by dissolving 20 to 200 mmol / L of 3-acrylamidophenylboronic acid as a monomer having a boronic acid group, 10 to 100 mmol / L of (3-acrylamidopropyl)trimethylammonium chloride, 500 to 1000 mmol / L of N,N-dimethylacrylamide, 50 to 200 mmol / L of a crosslinker, and 20 to 100 mmol / L of a polymerization initiator in a solvent. The content of the monomer having a boronic acid group is preferably about 0.2 to 20 times, and more preferably about 0.5 to 5 times, the content of the monomer having a cationic group.

[0024] In the above composition, 10 to 100 mmol / L of (3-acrylamidopropyl)trimethylammonium chloride may be replaced with a combination of 5 to 50 mmol / L of N-(3-aminopropyl)methacrylamide hydrochloride and 5 to 50 mmol / L of (3-acrylamidopropyl)trimethylammonium chloride.

[0025] To manufacture a concentration-determining member by photopolymerization, first, a monomer solution is applied to a measurement substrate, and then the substrate is irradiated with ultraviolet light for 1 to 3 hours through a photomask of a predetermined shape. Examples of ultraviolet light include g-line (wavelength 436 nm), h-line (wavelength 405 nm), i-line (wavelength 365 nm), KrF excimer laser light (wavelength 248 nm), and ArF excimer laser light (wavelength 193 nm). The exposure dose is usually 3 to 9 J / cm. 2 In this way, an organic coating having a predetermined shape is formed.

[0026] The measurement substrate on which the organic coating is formed is immersed in an aqueous dye solution and stirred. The aqueous dye solution can be a solution containing the above-mentioned anionic dye at a concentration of about 0.01 to 0.1 mmol / L. Examples of the solvent used here include a buffer solution with a pH of 7 to 8. Examples of the buffer solution that can be used include N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) (HEPES) at a concentration of about 1 to 20 mmol / L. After 1 to 10 minutes, the measurement substrate is removed, washed with pure water, and dried using a fan or the like to obtain the concentration-determining member of the present invention, which has a colored pattern containing an organic coating having cationic groups and an anionic dye.

[0027] When the concentration determining member is produced by dip coating, stencil printing, or inkjet printing, a polymer having a cationic group is first synthesized using a monomer solution containing a monomer having a cationic group.

[0028] The monomer solution can be prepared by dissolving, for example, 10 to 100 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 500 to 1000 (mmol / L) of dimethylacrylamide, and 20 to 100 (mmol / L) of a polymerization initiator in a solvent. The polymerization initiator and solvent can be those described above. The resulting monomer solution was freeze-degassed and then immersed in an oil bath at 50-70°C to carry out a polymerization reaction overnight under a nitrogen atmosphere. After the flask was cooled to room temperature, the contents were dropped into a poor solvent such as acetone to cause reprecipitation, and the recovered solid was dried in vacuum to obtain a polymer with cationic groups.

[0029] As described above, a polymer having a boronic acid group in addition to a cationic group can be synthesized by using a monomer solution further containing a monomer having a boronic acid group. In this case, the monomer solution can be prepared by dissolving, for example, 10 to 100 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 10 to 100 (mmol / L) of 3-acrylamidophenylboronic acid as a monomer having a boronic acid group, 500 to 1,000 (mmol / L) of dimethylacrylamide, and 20 to 100 (mmol / L) of a polymerization initiator in a solvent.

[0030] (Dip coating method) First, a raw material aqueous solution containing a polymer having a cationic group and an anionic dye is prepared. The polymer concentration can be about 1 to 10% by mass, and the anionic dye concentration can be about 0.01% by mass. A measurement substrate is immersed in the raw material aqueous solution to impregnate the measurement substrate with the raw material aqueous solution. The immersion time can be, for example, about 30 seconds.

[0031] The measurement substrate impregnated with the raw material aqueous solution is dried to form a colored pattern containing an organic coating having cationic groups and an anionic dye. The drying method is not particularly limited, and examples thereof include air drying.

[0032] (stencil printing method) An organic coating containing a polymer having cationic groups is formed on a measurement substrate, and an aqueous dye solution containing an anionic dye is stencil printed on the surface of the organic coating to form a colored pattern containing the organic coating having cationic groups and the anionic dye.

[0033] The organic coating can be formed by dropping a polymer solution onto the substrate for measurement, spreading it over the entire surface, and then drying it. Alternatively, the organic coating can be formed by immersing the substrate for measurement in the polymer solution and then drying it. Drying can be performed by any method.

[0034] To form a colored pattern, a stencil having openings of a predetermined shape is first placed on the organic coating. Stencil printing can be performed by spraying an aqueous dye solution containing an anionic dye onto the stencil and drying it. Drying can be performed by any method.

[0035] Two or more organic coatings can be formed on the measurement substrate using two or more polymer solutions with different compositions. For example, two types of organic coatings can be used: one containing only cationic groups, and the other containing both cationic groups and boronic acid groups. Three types of organic coatings can be formed by further providing organic coatings with different boronic acid group contents.

[0036] The concentration of the anionic dye in the aqueous dye solution to be sprayed onto a predetermined region of the organic coating can be, for example, about 1 to 10 mmol / L. The aqueous dye solution can be filled into an atomizer, for example, and sprayed. Two or more aqueous dye solutions containing different anionic dyes may be used. A colored pattern can be formed by stencil printing using any combination of a polymer solution for forming an organic coating and an aqueous dye solution.

[0037] (Inkjet printing method) An organic coating containing a polymer having cationic groups is formed on a measurement substrate, and a dye aqueous solution containing an anionic dye is inkjet printed in a predetermined shape on the surface of the organic coating to form a colored pattern containing the organic coating having cationic groups and the anionic dye. The organic coating can be formed on the measurement substrate by the same method as in the stencil printing method described above. The measurement substrate on which the organic coating has been formed is set in the paper tray of an inkjet printer.

[0038] The concentration of the anionic dye in the aqueous dye solution to be printed on the surface of the organic coating can be, for example, about 1 to 10 mmol / L. The aqueous dye solution is stored in an ink tank of the inkjet printer. In this way, by inkjet printing an aqueous dye solution onto the surface of the organic coating, a colored pattern containing an organic coating having cationic groups and an anionic dye can be formed.

[0039] When the above-mentioned dip coating method, stencil printing method, or ink jet printing method is employed, a large number of colored patterns can be formed in a short time, which allows for efficient production of concentration determining members.

[0040] The concentration determining member of the present invention can be suitably used for determining the concentration of hypochlorous acid or hypochlorite ions. As the test liquid, any solution that may contain hypochlorous acid or hypochlorite ions can be used.

[0041] In determining the concentration, the concentration-determining member of the present invention, which has a colored pattern containing an organic coating having a cationic group and an anionic dye, is immersed in the test liquid for about 1 to 10 minutes. The temperature of the test liquid is not particularly limited, but is preferably about 20 to 30°C.

[0042] When hypochlorous acid is not present in the test liquid, the color of the colored pattern does not change, but when hypochlorous acid is present, the color disappears. The mechanism behind this is as follows. The colored pattern in the concentration-determining member of the present invention is formed by adsorption of an anionic dye to the cationic groups of the organic coating. When the colored pattern comes into contact with hypochlorous acid, the positive charge of the organic coating disappears through a reaction with hypochlorous acid. As a result, the anionic dye is released from the organic coating, and the colored pattern becomes invisible (discolored). At the same time, the anionic dye is decomposed by the reaction with hypochlorous acid, and the color is discolored.

[0043] The change in color tone of the colored pattern can be confirmed by measuring the absorbance at a wavelength appropriate for the type of anionic dye. For example, in the case of Fast Green FCF, the absorbance is measured at 620 nm, and in the case of Acid Red 18, the absorbance is measured at 513 nm.

[0044] When boronic acid groups are present in addition to cationic groups in the organic coating of the colored pattern, hypochlorous acid reacts preferentially with the boronic acid groups as shown below.

[0045] [ka]

[0046] In this case, the charge state of the organic coating does not change at all, so there is no effect on the adsorption of the anionic dye. Until the boronic acid groups in the organic coating are consumed, the charge state of the organic coating does not change at all, so the anionic dye remains adsorbed to the cationic groups. Furthermore, the anionic dye does not decompose. In other words, the colored pattern does not fade with low concentrations of hypochlorous acid, and the higher the boronic acid content, the more the discolored region shifts toward the higher concentration side. By adjusting the content of boronic acid groups, the hypochlorous acid concentration and reaction time at which decolorization occurs can be controlled.

[0047] According to the concentration determination method of the present invention, it is possible to simply determine the concentration of hypochlorous acid in a test liquid by checking the color tone of the colored pattern. [Example]

[0048] The present invention will be specifically described below by way of examples, but the scope of the present invention should not be construed as being limited by the specific examples shown below.

[0049] A test piece for the concentration-determining member was prepared by forming a colored pattern containing an organic coating having a cationic group and an anionic dye on the surface of a measurement substrate. First, monomer solutions (monomer solution 1, monomer solution 2, and monomer solution 3) for forming the colored pattern were prepared according to the following formulations.

[0050] <Monomer solution 1> The polymer was prepared by dissolving 40 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 910 (mmol / L) of dimethylacrylamide, 100 (mmol / L) of a crosslinker, and 25 (mmol / L) of a polymerization initiator in a solvent. Monomer solution 1 is a monomer solution for forming a colored pattern having an organic coating having only cationic groups without boronic acid groups.

[0051] <Monomer solution 2> The polymer was prepared by dissolving 40 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 30 (mmol / L) of 3-acrylamidophenylboronic acid as a monomer having a boronic acid group, 860 (mmol / L) of dimethylacrylamide, 100 (mmol / L) of a crosslinker, and 25 (mmol / L) of a polymerization initiator in a solvent.

[0052] <Monomer solution 3> The polymer was prepared by dissolving 40 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 100 (mmol / L) of 3-acrylamidophenylboronic acid as a monomer having a boronic acid group, 810 (mmol / L) of dimethylacrylamide, 100 (mmol / L) of a crosslinker, and 25 (mmol / L) of a polymerization initiator in a solvent. Monomer solution 2 and monomer solution 3 are monomer solutions for forming a colored pattern having an organic coating having a boronic acid group in addition to a cationic group.

[0053] In both monomer solutions, methylenebisacrylamide was used as the cross-linking agent, 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) was used as the polymerization initiator, and a mixture of DMSO and HO (volume ratio 1:1) was used as the solvent.

[0054] As anionic dyes, Fast Green FCF (FG) and Acid Red 18 (AR18) were used to prepare the following two types of aqueous dye solutions. Dye aqueous solution a: 0.02 mmol / L aqueous solution of First Green FCF (FG) Dye aqueous solution b: 0.02 mmol / L aqueous solution of Acid Red 18 (AR18) The dye solution was prepared by dissolving it in 100 mL of a pH 7.4 buffer solution, 10 mmol / L HEPES (N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid)).

[0055] Using the monomer solution and the aqueous dye solution prepared as described above, a colored pattern was formed on a measurement substrate by the following procedure to prepare a test piece for the concentration-determining member. As the measurement substrate, a membrane filter (Y100, manufactured by Toyo Roshi Kaisha, Ltd.) cut into a size of 6 cm x 2 cm was used.

[0056] The monomer solutions and aqueous dye solutions were combined as shown in the table below to form five different colored patterns.

[0057] [Table 1]

[0058] The monomer solution of each composition was freeze-degassed and then dripped onto a substrate in a nitrogen-purged glove box to form a coating of the monomer solution. The coating was then irradiated with ultraviolet light (365 nm) for 1 hour through a photomask with a circular light-transmitting area. After irradiation, the substrate was immersed in a dye solution and stirred for 3 minutes, then removed and washed with pure water. The substrate was then dried with cold air from a hair dryer to produce a circular colored pattern.

[0059] The hypochlorous acid concentration in the test solution was determined using the test strips with each colored pattern formed. As the test solution, several aqueous solutions (hypochlorous acid water) with different hypochlorous acid (HClO) concentrations were prepared. The hypochlorous acid water (pH 6.5) was prepared by neutralizing sodium hypochlorite with 0.9 equivalents of hydrochloric acid and appropriately diluting it with water.

[0060] During the measurement, the test piece was immersed in 10 mL of the test solution measured in a glass screw tube and stirred with a stirrer. After the specified time, it was removed and washed with water, and the state of the colored pattern was observed. The immersion times after the specified time were 1 minute, 3 minutes, and 10 minutes. When FG was used as the anionic dye, the absorbance was measured at 620 nm, and when AR18 was used, the absorbance was measured at 513 nm. A UV-visible spectrophotometer (JASCO V-650) was used to measure the absorbance.

[0061] Figure 1 shows the results for coloration pattern 1. When the sample was immersed in hypochlorous acid water for 10 minutes, the color remained at a hypochlorous acid concentration of 0 to 0.1 mM, but became colorless at higher concentrations. When the sample was immersed for 3 minutes, some coloration was observed even at 0.3 mM, but became almost colorless at 0.6 mM. When the immersion time was shortened to 1 minute, coloration was observed even at 1 mM, and became colorless at concentrations of 3 mM or higher.

[0062] Figure 2 shows the results for coloring pattern 2. Coloring pattern 2 has boronic acid groups in addition to cationic groups in the organic coating. When the immersion time was 10 minutes, the sample became almost colorless at 3 mM and completely colorless at 10 mM. When the immersion time was 3 minutes, coloration was observed even at 3 mM and completely colorless at 10 mM. When the immersion time was 1 minute, some coloration was observed even at 10 mM. Compared to coloring pattern 1 (Figure 1), it can be seen that the response region has shifted overall to the higher concentration side.

[0063] Figure 3 shows the results for Coloring Pattern 3. Coloring Pattern 3 has an even higher content of boronic acid groups in the organic coating than Coloring Pattern 2. When the immersion time was 10 minutes, the sample became almost colorless at 6 mM and completely colorless at 10 mM. When the immersion time was 3 or 1 minute, the sample did not become colorless even at 10 mM, and remained colored. These results demonstrate that the response sensitivity can be controlled by changing the boronic acid content in the organic coating.

[0064] Figures 4 to 6 show the color change behavior of the three types of colored patterns for each immersion time. It can be seen that, regardless of the immersion time, there is a clear difference in the response characteristics between the colored patterns. If different colored patterns with different shapes are combined on a single piece of filter paper, it may be possible to create a test paper that can display hypochlorous acid concentration in a short, one-step measurement without the need for additives.

[0065] Figure 7 shows the results for coloring patterns 4 and 5. The immersion time in the test solution was 10 minutes. It was confirmed that when the red dye (AR18) was used as the anionic dye, response behavior similar to that of the blue dye (FG) was observed.

[0066] Next, a colored pattern is formed on the surface of the measurement substrate by a different method to prepare a test piece of the concentration-determining member. First, the polymers (Q1-2, B1Q) for preparing the colored pattern are 0.4 -2) was prepared according to the following recipe.

[0067] <q1-2> A monomer solution was prepared by dissolving 100 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 900 (mmol / L) of dimethylacrylamide, and 25 (mmol / L) of a polymerization initiator in a solvent. The resulting monomer solution was freeze-degassed and then immersed in an oil bath at 60°C to carry out a polymerization reaction overnight under a nitrogen atmosphere. After the flask was cooled to room temperature, the contents were dropped into a poor solvent such as acetone to cause reprecipitation. The recovered solid was dried in vacuum to obtain the polymer. <q1-2>obtained. polymer <q1-2>is a polymer for forming a colored pattern with an organic coating having only cationic groups without boronic acid groups.

[0068] <B1Q 0.4 -2> A monomer solution was prepared by dissolving 40 (mmol / L) of (3-acrylamidopropyl)trimethylammonium chloride as a monomer having a cationic group, 100 (mmol / L) of 3-acrylamidophenylboronic acid as a monomer having a boronic acid group, 860 (mmol / L) of dimethylacrylamide, and 25 (mmol / L) of a polymerization initiator in a solvent. A polymer was prepared by the same method as described above, except that the obtained monomer solution was used. <B1Q 0.4 -2> was obtained. polymer <B1Q 0.4 -2> is a polymer for forming a colored pattern having an organic coating having a boronic acid group in addition to a cationic group.

[0069] In the synthesis of all polymers, 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) was used as the polymerization initiator, and a mixture of DMSO and H2O (volume ratio 1:1) was used as the solvent.

[0070] A colored pattern was formed on a measurement substrate using the polymer prepared as described above and an anionic dye. The following anionic dyes were prepared. First Green FCF (FG) Acid Red 18 (AR18) Sunset Yellow FCF(SY) Acid Red 27 (AR27) Brilliant Blue FCF(BB) Indigo carmine

[0071] <Sample production by dip coating> First, polymers and anionic dyes were combined and dissolved in water as shown in the table below to prepare polymer inks 1 to 4. Distilled water was used. The polymer concentration was 5% by mass, and the dye concentration was 0.2 or 0.5 mmol / L.

[0072] [Table 2]

[0073] A test piece for the concentration determination component was prepared by immersing one end of litmus paper (cut into 1 x 5 cm pieces) in polymer ink for approximately 30 seconds, then removing it and allowing it to dry naturally. The resulting test piece was immersed in a test solution containing a predetermined concentration of hypochlorous acid water for a predetermined time, and the color change was observed. The immersion times were 1, 3, and 10 minutes. The test solution did not contain polyol or pH buffer.

[0074] The colored patterns of test pieces using polymer inks 1 and 2 were observed after immersion. Specifically, the absorbance of each colored pattern was measured at 626 nm using a UV-visible spectrophotometer (JASCO V-650). Figures 8, 9, and 10 show the results after immersion for 1 minute, 3 minutes, and 10 minutes, respectively.

[0075] As shown in Figure 8, when the immersion time was 1 minute, the sample using polymer ink 1 gradually faded as the hypochlorous acid concentration increased, becoming completely colorless at 3 mM. The polymer in polymer ink 1 does not contain boronic acid groups. On the other hand, the sample using polymer ink 2, which does have boronic acid groups, only showed a slight change, becoming slightly lighter at 3 mM.

[0076] After an immersion time of 3 minutes, the discoloration region shifted to the lower concentration side, as shown in Figure 9, and clear discoloration was observed even with Polymer Ink 2 at 3 mM. After an immersion time of 10 minutes, as shown in Figure 10, the discoloration region shifted even further to the lower concentration side, with Polymer Ink 1 becoming colorless at 0.3 mM. Polymer Ink 2 also became nearly colorless at 3 mM.

[0077] The colored patterns of test pieces using polymer inks 3 and 4 were observed after immersion. Specifically, the absorbance of each colored pattern was measured at 511 nm using a UV-visible spectrophotometer (JASCO V-650). Figures 11, 12, and 13 show the results after immersion for 1 minute, 3 minutes, and 10 minutes, respectively.

[0078] The behavior was generally similar to the results shown in Figures 8-10, but the response region tended to shift slightly toward higher concentrations. Specifically, as shown in Figure 11, when the immersion time was 1 minute, samples using polymer inks 3 and 4 gradually faded as the hypochlorous acid concentration increased, but complete colorlessness was not observed. In the case of polymer ink 3, when the immersion time was 3 minutes, it became colorless at 3 mM as shown in Figure 12, and when the immersion time was 10 minutes as shown in Figure 13, it became colorless at 1 mM.

[0079] From the above results, it was confirmed that in colored patterns obtained by the dip coating method using polymer ink, the response behavior (discoloration region) of the color change in response to hypochlorous acid can be controlled by the type and content of functional groups contained in the polymer.

[0080] <Sample creation by stencil printing (1 spot)> polymer <q1-2>and <B1Q 0.4 Each of the above-mentioned compounds was dissolved in water to prepare a polymer solution with a concentration of 5% by mass. Each of the anionic dyes (AR18, FG, SY, AR27, BB, and Indigo) was dissolved in water to prepare a dye solution with a concentration of 5 mmol / L. The polymer solution and the dye solution were combined to form a colored pattern using the following method.

[0081] First, 450 μL of the polymer solution was dropped onto a piece of litmus paper cut to a size of 4 × 5 cm, and after spreading, it was dried. An overhead projector sheet with four circular openings, each 1 cm in diameter, was used as a stencil to cover the coating surface, and the aqueous dye solution filled in the atomizer was sprayed onto it. The sprayed coating was then dried and cut into a size of 2 × 2.5 cm for measurement.

[0082] The obtained test piece was immersed in a test solution containing a predetermined concentration of hypochlorous acid water for a predetermined time, and the rate of absorbance change at the maximum absorption wavelength was measured. The rate of absorbance change was calculated by (absorbance A after a predetermined time / initial absorbance A0). The immersion time was 1 minute, 3 minutes, and 10 minutes. The test solution did not contain polyol or pH buffer.

[0083] Figure 14 shows the results of a colored pattern using polymer solution 1 (Q1-2) after immersion for 1 minute. When the immersion time was 1 minute, there was almost no change in color tone when the hypochlorous acid concentration was 3 mM or less. In the colored pattern using AR27, some degree of pale coloring was observed at 3 mM.

[0084] Figure 15 shows the results of immersion of the colored pattern using polymer solution 1 (Q1-2) for 3 minutes. Figure 15 shows that the colored patterns using AR18, AR27, and Indigo became almost colorless at 2 mM, and became colorless except for FB and BB at 3 mM. Figure 16 shows the polymer solution 2 (B1Q 0.4 Figure 15 shows the results after 3 minutes of immersion of the colored pattern using -2), and no significant changes were observed.

[0085] The results after 10 minutes of immersion are shown in Figures 17 and 18. Figure 17 shows the coloration pattern obtained using polymer solution 1 (Q1-2). It can be seen that the response region shifts to lower concentrations. At 1 mM, half of the dyes become colorless, and at 3 mM, all of the dyes become colorless. Polymer solution 2 (B1Q 0.4 In the case of the colored pattern using -2), only slight fading was observed at 3 mM, as shown in FIG.

[0086] <Sample creation by stencil printing (2 spots)> polymer <q1-2>and <B1Q 0.4 -2> was dissolved in water to prepare a polymer solution with a concentration of 5% by mass. Each anionic dye (AR18, FG) was dissolved in water to prepare a dye aqueous solution with a concentration of 5 mmol / L. The polymer solution and anionic dye were combined to form a colored pattern using the following method.

[0087] The combinations of polymer solutions and anionic dyes are shown in the table below.

[0088] [Table 3]

[0089] First, 200 μL of polymer solution (Q1-2) was dropped evenly onto half of the area (4 × 2.5 cm) of litmus paper cut into 4 × 5 cm, and then dried. 200 μL of polymer solution (B1Q) was dropped onto the remaining half of the area. 0.4 -2) was dripped evenly onto the surface of the resulting coating film and allowed to dry. An OHP sheet with four 1 cm diameter circular openings was placed on the surface of the resulting coating film as a stencil, and the aqueous dye solution filled in the atomizer was sprayed onto it. The coating film onto which the aqueous dye solution had been sprayed was then dried, producing a two-spot stencil print sample. This was then divided into two pieces and used for measurement.

[0090] The obtained test piece was immersed in a test solution containing a predetermined concentration of hypochlorous acid water for a predetermined time, and the absorbance was measured. The immersion time was 1 minute, 3 minutes, and 10 minutes. The test solution did not contain polyol or pH buffer.

[0091] Figure 19 shows the results when the immersion time was 1 minute. As shown in Figure 19(a), when colored with AR18, colored pattern 6 using polymer solution (Q1-2) became almost colorless at 3 mM, and colored pattern 6 using polymer solution (B1Q 0.4 Colored pattern 7 containing polymer solution (Q1-2) also became almost colorless at 10 mM. On the other hand, when colored with FG, as shown in Figure 19(b), all colored patterns remained colored up to 3 mM, and only colored pattern 8 using polymer solution (Q1-2) became colorless at 10 mM.

[0092] Figures 20 and 21 show the results for immersion times of 3 and 10 minutes, respectively. As the immersion time increases, the discoloration region shifts toward lower concentrations. In both cases, the colored patterns stained with AR18 (Figures 20(a) and 21(a)) tended to discolor at a slightly lower concentration than the colored patterns stained with FG (Figures 20(b) and 21(b)).

[0093] <Sample creation by stencil printing (3 spots)> polymer <q1-2>and <B1Q 0.4 -2> was dissolved in water to prepare a polymer solution with a concentration of 5% by mass. Each anionic dye (AR18, FG) was dissolved in water to prepare a dye aqueous solution with a concentration of 5 mmol / L. The polymer solution and the dye aqueous solution were combined to form a colored pattern using the following method.

[0094] The combinations of the polymer solution and the anionic dye are the same as coloring patterns 6, 7, and 9 shown in Table 3 above.

[0095] First, 140 μL of polymer solution (Q1-2) was evenly dropped onto approximately 1 / 3 of the area (4 × 1.75 cm) of a litmus paper cut into 4 × 5 cm pieces and allowed to dry. 260 μL of polymer solution (B1Q) was added to the remaining area. 0.4 -2) was dripped evenly onto the surface of the resulting coating film and allowed to dry. An OHP sheet (stencil 1) with four 1 cm diameter circular openings was placed on the surface of the resulting coating film, and the AR18 aqueous solution filled in the atomizer was sprayed onto it. An OHP sheet (stencil 2) with two 1 cm diameter circular openings was placed on the same coating film, and the FG aqueous solution was sprayed onto it. The coating film onto which the dye aqueous solution had been sprayed was then dried, and a three-spot stencil printing sample was prepared. This was then divided into two pieces for measurement.

[0096] The obtained test piece was immersed in a test solution containing a predetermined concentration of hypochlorous acid water for a predetermined time, and the absorbance was measured. The immersion time was 1 minute, 3 minutes, and 10 minutes. The test solution did not contain polyol or pH buffer.

[0097] Figure 22 shows the results when the immersion time was 1 minute. Colored pattern 6 containing Q1-2 and AR18 became almost colorless at 3 mM. 0.4 The response region of the staining patterns containing -2 (staining patterns 7 and 9) is shifted to the higher concentration side. Specifically, staining pattern 7 stained with AR18 became significantly lighter at 10 mM, while staining pattern 9 stained with FG showed clear coloration even at 10 mM.

[0098] Figure 23 shows the results when the immersion time was 3 minutes. Colored pattern 6 containing Q1-2 and AR18 became completely colorless at 2 mM, and B1Q 0.4 The colored pattern 7 containing B1Q-2 and AR18 became completely colorless at 10 mM. 0.4 Coloring pattern 9 containing -2 and FG showed slight coloring even at 10 mM. In both coloring patterns, the response region shifted significantly to the low concentration side when the immersion time was 10 minutes, as shown in Figure 24. Furthermore, the response concentration region differed for each region.

[0099] These results demonstrate that by changing the combination of polymer and dye, it is possible to create various printed patterns with different response concentration ranges using the stencil method, and that it is possible to create a detection chip with multiple display areas of any color tone and shape that change gradually depending on the hypochlorous acid concentration. Furthermore, compared with the response of the dip-coated sample, the response region of the stencil-printed sample appears to be slightly shifted to the higher density side, which is presumably because the association state between the polymer and dye in the substrate differs somewhat depending on the sample preparation method.

[0100] <Sample creation by inkjet printing> polymer <q1-2>and <B1Q 0.4 Each of the above-2> was dissolved in water to prepare a polymer solution with a concentration of 5% by mass. Each of the anionic dyes (AR18, Indigo) was dissolved in water to prepare a dye aqueous solution with a concentration of 5 mmol / L. The polymer solution and the dye aqueous solution were combined to form a colored pattern using the following method.

[0101] First, 1.8 mL of the polymer solution was dropped onto a piece of litmus paper cut to 8 x 10 cm, and after spreading it over the entire surface, it was allowed to dry. This was then placed in the paper tray of an inkjet printer (EPSON PX-105), and the ink tank was filled with a dye solution to print a circle. The piece was then cut into a 2 x 2.5 cm size for use in the measurement.

[0102] The obtained test strip was immersed in a test solution containing a predetermined concentration of hypochlorous acid water for a predetermined time, and the absorbance was measured. The immersion times were 1 minute, 3 minutes, and 10 minutes. When AR18 was used as the anionic dye, the absorbance was measured at 511 nm, and when Indigo was used, the absorbance was measured at 617 nm. Note that the test solution did not contain polyol or pH buffer.

[0103] Figure 25 shows the results when the immersion time was 1 minute. When colored with either AR18 or Indigo, the colored pattern using polymer solution (Q1-2) became almost colorless at 4 mM. 0.4 In the case of the coloring pattern using -2), when colored with AR18, it became almost colorless at 10 mM, but when colored with Indigo, it was confirmed that it did not become colorless even at 10 mM.

[0104] Figure 26 shows the results when the immersion time was 3 minutes. When colored with either AR18 or Indigo, the colored pattern using polymer solution (Q1-2) became almost colorless at 2 mM, and the colored pattern using polymer solution (B1Q 0.4 In the case of the colored pattern using -2), the color became almost colorless at 10 mM.

[0105] Figure 27 shows the results when the immersion time was 10 minutes. When colored with either AR18 or Indigo, the colored pattern using polymer solution (Q1-2) became almost colorless at 1 mM. 0.4 The coloring pattern using -2) was almost colorless at 4 mM when stained with AR18, and almost colorless at 10 mM when stained with Indigo.

[0106] According to the present invention, it has become possible to easily determine the concentration of hypochlorous acid in a test liquid from a change in color tone.

Claims

1. A measurement substrate; a colored pattern provided on the surface of the measurement substrate; A concentration determining member comprising: The coloring pattern is Contains an organic coating having cationic groups and an anionic dye A concentration determining member characterized by:

2. 2. The concentration determining member according to claim 1, wherein the organic coating further comprises a boronic acid group.

3. 3. The concentration determining member according to claim 1, wherein the cationic group is selected from the group consisting of a quaternary ammonium group, a tertiary ammonium group, and a primary ammonium group.

4. 4. The concentration determining member according to claim 3, wherein the boronic acid group is selected from the group consisting of a phenylboronic acid group and an alkylboronic acid group.

5. 3. The concentration-determining member according to claim 1, wherein the anionic dye is selected from the group consisting of Fast Green FCF (FG), Acid Red 18 (AR18), Sunset Yellow FCF (SY), Acid Red 27 (AR27), Brilliant Blue FCF (BB), Indigo Calamine (Indigo), Acid Red 112, Acid Red 114, Direct Yellow 50, Indigotetrasulfonic acid, and Chrysophenine.

6. A method for manufacturing the concentration determining member according to claim 1, comprising the steps of: A raw material aqueous solution containing a polymer having a cationic group and an anionic dye is impregnated into a measurement substrate; The measurement substrate impregnated with the raw material aqueous solution is dried to form a colored pattern containing an organic coating having a cationic group and an anionic dye. A manufacturing method characterized by:

7. A method for manufacturing the concentration determining member according to claim 1, comprising the steps of: forming an organic coating containing a polymer having a cationic group on a measurement substrate; A dye aqueous solution containing the anionic dye is stencil printed on the surface of the organic coating to form a colored pattern containing the organic coating having a cationic group and the anionic dye. A manufacturing method characterized by:

8. A method for manufacturing the concentration determining member according to claim 1, comprising the steps of: forming an organic coating containing a polymer having a cationic group on a measurement substrate; A dye aqueous solution containing the anionic dye is ink-jet printed in a predetermined shape on the surface of the organic coating to form a colored pattern containing the organic coating having a cationic group and the anionic dye. A manufacturing method characterized by:

9. 9. The method for producing a concentration determining member according to claim 6, wherein the polymer is synthesized by polymerizing a monomer having a cationic group in a solvent in the presence of a polymerization initiator.

10. 10. The method for manufacturing a concentration-determining member according to claim 9, wherein the monomer having a cationic group is selected from the group consisting of (3-acrylamidopropyl)trimethylammonium chloride, N-(3-dimethylaminopropyl)acrylamide, N-(3-dimethylaminopropyl)methacrylamide, N-(2-dimethylaminoethyl)acrylamide, N-(2-dimethylaminoethyl)methacrylamide, and N-(3-aminopropyl)methacrylamide hydrochloride.

11. 3. A method for manufacturing the concentration determining member according to claim 2, comprising the steps of: A raw material aqueous solution containing a polymer having a cationic group and a boronic acid group and an anionic dye is impregnated into a measurement substrate; The measurement substrate impregnated with the raw material aqueous solution is dried to form a colored pattern containing an organic coating having a cationic group and a boronic acid group and an anionic dye. A manufacturing method characterized by:

12. 3. A method for manufacturing the concentration determining member according to claim 2, comprising the steps of: forming an organic coating containing a polymer having a cationic group and a boronic acid group on a measurement substrate; A dye aqueous solution containing the anionic dye is stencil printed on the surface of the organic coating to form a colored pattern containing the organic coating having a cationic group and a boronic acid group and the anionic dye. A manufacturing method characterized by:

13. 3. A method for manufacturing the concentration determining member according to claim 2, comprising the steps of: forming an organic coating containing a polymer having a cationic group and a boronic acid group on a measurement substrate; A dye aqueous solution containing the anionic dye is ink-jet printed in a predetermined shape on the surface of the organic coating to form a colored pattern containing the organic coating having a cationic group and a boronic acid group and the anionic dye. A manufacturing method characterized by:

14. The method for manufacturing a concentration determining member according to any one of claims 11 to 13, wherein the polymer is synthesized by polymerizing a monomer having a cationic group and a monomer having a boronic acid group in a solvent in the presence of a polymerization initiator.

15. 15. The method for manufacturing a concentration-determining member according to claim 14, wherein the monomer having a cationic group is selected from the group consisting of (3-acrylamidopropyl)trimethylammonium chloride, N-(3-dimethylaminopropyl)acrylamide, N-(3-dimethylaminopropyl)methacrylamide, N-(2-dimethylaminoethyl)acrylamide, N-(2-dimethylaminoethyl)methacrylamide, and N-(3-aminopropyl)methacrylamide hydrochloride.

16. 15. The method for producing a concentration determining member according to claim 14, wherein the monomer having a boronic acid group is selected from the group consisting of 3-acrylamidophenylboronic acid and 4-vinylphenylboronic acid.

17. A method for determining a concentration of hypochlorous acid using the concentration determining member according to claim 1 or 2, The concentration determination method involves contacting a test liquid with the colored pattern, and determining that no hypochlorous acid is present in the test liquid if the colored pattern does not change after 1 to 10 minutes.

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