Test paper for detecting concentration of o-phthalaldehyde disinfectant and preparation method of test paper

Abstract

The invention discloses o-phthalaldehyde disinfectant concentration detection test paper and a preparation method thereof.The preparation method comprises the steps that S1, a color developing agent, a color developing accelerant and a stabilizer are dissolved in purified water, a solution A is prepared, and the color developing agent accounts for 0.1-10 wt%, the color developing accelerant accounts for 0.1-10 wt%, and the stabilizer accounts for 0.1-10 wt%; s2, the filter paper is completely soaked in the liquid A for 1-2 min, and the filter paper is dried after being completely soaked; s3, uniformly dissolving a film-forming agent in purified water to prepare 0.1-10wt% of a solution B; s4, immersing the filter paper dried in the step S2 into a solution B, continuing for 10-30s, and then drying; and S5, cutting the dried filter paper, and pasting the cut filter paper on a substrate paperboard to obtain the phthalic dicarboxaldehyde disinfectant concentration detection test paper. The test paper for detecting the concentration of the o-phthalaldehyde disinfectant has the advantages that the validity period is as long as 2 years, the color development effect is stable, and the concentration of the o-phthalaldehyde disinfectant can be effectively and accurately reflected.

Description

Technical Field

[0001] The invention relates to the technical field of chemical detection, and in particular to a test paper for detecting concentration of an o-phthalaldehyde disinfectant and a preparation method thereof. Background Art

[0002] The o-phthalaldehyde disinfectant concentration test paper is a test card specifically used to measure the effective content of o-phthalaldehyde disinfectant. It is often developed and produced in conjunction with the corresponding disinfectant. It can accurately measure the concentration of o-phthalaldehyde disinfectant at 0.2%, 0.3%, 0.4% and 0.5% through different color changes, enabling medical staff to monitor the concentration of o-phthalaldehyde disinfectant on-site, ensuring effective high-level disinfection of medical devices and avoiding the occurrence of hospital infection incidents due to incomplete disinfection of equipment.

[0003] The o-phthalaldehyde disinfectant concentration test paper currently on the market mainly includes four color development methods: the initial color is white, and the qualified color is yellow; the initial color is white, and the qualified color is pink; the initial color is blue, and the qualified color is green; the initial color is blue, and the qualified color is purple. There are two main color development principles: one is that the aldehyde group and sodium sulfite generate alkaline substances, which change the color of the phenolphthalein indicator, and the other is that o-phthalaldehyde reacts with amino acids to generate yellow substances. Chinese invention patent CN105548166A discloses a o-phthalaldehyde disinfectant concentration range detection test paper, which controls the color change by pulp modification. The main color change principle is that the aldehyde group and sodium sulfite generate alkaline substances, which change the color of the phenolphthalein indicator. However, the preparation of the test paper according to the method of the patent has cumbersome preparation steps for the filter paper in the early stage, and the color change principle of the latter part controls the color development by changing the pH, which is easily affected by the pH of the o-phthalaldehyde disinfectant, resulting in inaccurate concentration. Chinese invention patent CN106970075A discloses a test paper for detecting o-phthalaldehyde concentration and its preparation method, the color change is a blue-to-green indication mode, the main color change principle is that o-phthalaldehyde reacts with amino acids to generate yellow substances, and the mixed reaction with blue-dyed filter paper shows green, which enhances color recognition, but when the concentration of o-phthalaldehyde disinfectant is low, the color development is still not obvious. Chinese invention patent CN107024473A discloses a rapid detection test paper for o-phthalaldehyde disinfectant concentration and its preparation method and application, which accelerates the reaction rate of o-phthalaldehyde and amino acids by adding organic acids, so that the o-phthalaldehyde concentration color development test time only needs 20s, but the components added to its A solution and B solution are many, the operation is complicated, and the organic acid itself is unstable in nature and easily decomposed in a high temperature environment, losing its function of accelerating the reaction rate.

[0004] In addition, the existing technology does not involve the study of the shelf life of the test paper for detecting the concentration of o-phthalaldehyde disinfectant. The shelf life of the o-phthalaldehyde disinfectant on the market is currently 2 years, and the shelf life of the test paper matched with it is basically 1 year. The validity periods of the two do not match, and the concentration of the o-phthalaldehyde disinfectant cannot be effectively detected in real time, which brings inconvenience to hospitals. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a test paper for detecting the concentration of an o-phthalaldehyde disinfectant and a preparation method thereof. The prepared o-phthalaldehyde disinfectant concentration test paper has a validity period of up to 2 years, a stable color development effect, and can effectively and accurately reflect the concentration of an o-phthalaldehyde disinfectant.

[0006] The technical solution of the present invention is:

[0007] On the one hand, the present invention provides a method for preparing a test paper for detecting concentration of o-phthalaldehyde disinfectant, comprising the following steps:

[0008] S1: dissolving a color developer, a color accelerator and a stabilizer in purified water to prepare a solution A, wherein the color developer is 0.1-10wt.%, the color accelerator is 0.1-10wt.%, and the stabilizer is 0.1-10wt.%;

[0009] S2 completely immerses the filter paper in solution A for 1-2 minutes, and then dries it after it is completely soaked;

[0010] S3: uniformly dissolving the film-forming agent in purified water to prepare 0.1-10wt.% of liquid B;

[0011] S4: immerse the filter paper dried in step S2 into liquid B for 10-30 seconds and then dry;

[0012] S5 cuts the dried filter paper and sticks it on the base cardboard to obtain the o-phthalaldehyde disinfectant concentration detection test paper.

[0013] Preferably, in step S1, the developer is an amino acid ester compound.

[0014] Preferably, the developer is one or more of glycine methyl ester, glycine ethyl ester, glycine tert-butyl ester, alanine methyl ester, alanine ethyl ester, alanine tert-butyl ester, lysine methyl ester, lysine ethyl ester, lysine tert-butyl ester, proline methyl ester, proline ethyl ester, proline tert-butyl ester, glutamate methyl ester, glutamate ethyl ester, glutamate tert-butyl ester, tyrosine methyl ester, tyrosine ethyl ester, tyrosine tert-butyl ester, serine methyl ester, serine ethyl ester, serine tert-butyl ester, tryptophan methyl ester, tryptophan ethyl ester, tryptophan tert-butyl ester, aspartic acid methyl ester, aspartic acid ethyl ester, aspartic acid tert-butyl ester, sarcosine methyl ester, sarcosine ethyl ester, sarcosine tert-butyl ester, valine methyl ester, valine ethyl ester and valine tert-butyl ester.

[0015] Preferably, in step S1, the color development accelerator is one or more of hydrogen phosphate, hydrogen sulfate and carbonate.

[0016] Preferably, in step S1, the stabilizer is one or more of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butylene glycol and polybutylene glycol.

[0017] Preferably, in steps S2 and S4, the drying temperature is 40-60°C.

[0018] Preferably, in step S3, the film-forming agent is one or both of chitosan and chitosan derivatives.

[0019] Preferably, the chitosan is one or more of chitosan with a deacetylation degree of 85%, chitosan with a deacetylation degree of 90%, and chitosan with a deacetylation degree of 95%; and the chitosan derivative is one or both of N-carboxymethyl chitosan and carboxypropyl chitosan.

[0020] On the other hand, the present invention provides a test paper for detecting the concentration of o-phthalaldehyde disinfectant, which is prepared by the preparation method of the o-phthalaldehyde disinfectant concentration test paper.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The o-phthalaldehyde disinfectant concentration detection test paper prepared by the present invention has strong stability, can accurately react to the concentrations of 0.2%, 0.3%, 0.4% and 0.5% of the o-phthalaldehyde disinfectant by color change, and can maintain a validity period of 2 years. When preparing the o-phthalaldehyde disinfectant concentration detection test paper, the present invention adds a film-forming agent to liquid B, firstly, when the o-phthalaldehyde disinfectant contacts the color developer in liquid A, due to the barrier of the film-forming agent, when the concentration of the disinfectant is lower than 0.3%, the test paper basically displays colorless, improves the limit of the reaction between o-phthalaldehyde and amino acids, and avoids the problem of light yellow color development and misinterpretation caused by the disinfectant concentration lower than 0.3% in the prior art; secondly, the addition of the film-forming agent ensures that the components such as the color developer adsorbed on the filter paper are more stable, and the validity period of the test paper can be extended to 2 years. Avoid waste of test strips due to the mismatch between the validity period of test strips currently on the market and that of phthalaldehyde disinfectants, and avoid the difficulty in detecting the expiration of the test strips that come with phthalaldehyde disinfectants when they are used in medical environments. If expired test strips are used, the concentration of the disinfectant will be misinterpreted, making it impossible to ensure effective high-level disinfection of medical devices, which may lead to incomplete disinfection of the devices and hospital infection incidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the actual color development diagram of the o-phthalaldehyde disinfectant concentration detection test paper in each embodiment and comparative example of the present invention. DETAILED DESCRIPTION

[0024] In order to enable persons skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0025] The experimental methods used in the following examples are all conventional methods, and the reagents used are all analytically pure or industrial grade.

[0026] Example 1

[0027] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of the present embodiment comprises the following steps:

[0028] S1: Weigh 10 g of tert-butyl lysine, 4 g of potassium dihydrogen phosphate, and 2 g of polypropylene glycol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain liquid A;

[0029] S2 completely immerses the filter paper in solution A for 2 minutes. After the filter paper is completely soaked, put it into an oven and dry it at 50°C.

[0030] S3 Weigh 2 g of N-carboxymethyl chitosan, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain liquid B;

[0031] S4: immerse the filter paper dried in step S2 into solution B, soak for 15 seconds, then put it into an oven and dry it at 50°C;

[0032] S5 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0033] Example 2

[0034] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of the present embodiment comprises the following steps:

[0035] S1: Weigh 20 g of glycine methyl ester, 5 g of potassium hydrogen sulfate, and 6 g of polyethylene glycol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain solution A;

[0036] S2 completely immerses the filter paper in solution A for 1 min. After the filter paper is completely soaked, put it into an oven and dry it at 60°C.

[0037] S3: Weigh 40 g of carboxypropyl chitosan, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain liquid B;

[0038] S4: immerse the filter paper dried in step S2 in solution B, soak for 30 seconds, then put it into an oven and dry it at 60°C;

[0039] S5 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0040] Example 3

[0041] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of the present embodiment comprises the following steps:

[0042] S1: Weigh 30 g of ethyl aspartate, 2 g of sodium carbonate, and 4 g of butanediol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain solution A;

[0043] S2 completely immerses the filter paper in liquid A for 2 minutes. After the filter paper is completely soaked, put it into an oven and dry it at 40°C.

[0044] S3 Weigh 20 g of chitosan with a deacetylation degree of 90%, add 5 mL of analytical grade citric acid and 100 mL of purified water to completely dissolve the chitosan, then add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain liquid B;

[0045] S4: immerse the filter paper dried in step S2 in solution B, soak for 10 seconds, then put it into an oven and dry it at 40°C;

[0046] S5 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0047] Comparative Example 1

[0048] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 1 comprises the following steps:

[0049] S1: Weigh 10 g of tert-butyl lysine, 4 g of potassium dihydrogen phosphate, and 2 g of polypropylene glycol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain liquid A;

[0050] S2 completely immerses the filter paper in solution A for 2 minutes. After the filter paper is completely soaked, put it into an oven and dry it at 50°C.

[0051] S3 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0052] Comparative Example 2

[0053] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 2 comprises the following steps:

[0054] S1: Weigh 20 g of glycine methyl ester, 5 g of potassium hydrogen sulfate, and 6 g of polyethylene glycol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain solution A;

[0055] S2 completely immerses the filter paper in liquid A for 1 min. After the filter paper is completely soaked, put it into an oven and dry it at 50°C.

[0056] S3 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0057] Comparative Example 3

[0058] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 3 comprises the following steps:

[0059] S1: Weigh 30 g of ethyl aspartate, 2 g of sodium carbonate, and 4 g of butanediol, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain solution A;

[0060] S2 completely immerses the filter paper in solution A for 2 minutes. After the filter paper is completely soaked, put it into an oven and dry it at 50°C.

[0061] S3 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0062] Comparative Example 4

[0063] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 4 comprises the following steps:

[0064] S1 Pulp Modification

[0065] The elemental chlorine-free bleached softwood kraft pulp was first oxidized and modified by 2,2,6,6-tetramethylpiperidone-1-oxyl free radical, NaBr and NaClO. The modification conditions were as follows: pulp concentration 1%, 2,2,6,6-tetramethylpiperidone-1-oxyl free radical 0.1mmol / g, NaBr 1mmol / g, reaction at room temperature (15-25℃), system pH value 10-11, NaClO addition amount 2.5mmol / g, when the pH value no longer decreased, the oxidation reaction was considered to be complete, the oxidized pulp was separated by filtration, and washed with deionized water to neutrality, and then paper-coated into 100g / m 2 Paper is available for backup;

[0066] S2 soaking solution preparation:

[0067] Accurately prepare 15% sodium sulfite solution and mix it evenly with 1% phenolphthalein anhydrous ethanol solution to form a mother solution;

[0068] S3 test paper preparation:

[0069] Soak the prepared paper in the above solution for 10 minutes, take it out, dry it in vacuum at room temperature, cut it and fix it on a non-absorbent substrate with glue, the substrate is a white plastic sheet, and the o-phthalaldehyde disinfectant concentration detection test paper is obtained.

[0070] Comparative Example 5

[0071] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 5 comprises the following steps:

[0072] S1: Add 0.3 g sodium bisulfite, 5 g urea, 10 g diammonium phosphate, and 5 mL 0.4 g / L methylene blue aqueous solution into 45 mL deionized water and dissolve completely to obtain a mother solution with uniform color.

[0073] S2: Cut ordinary filter paper into small squares of 1 cm × 1 cm, soak them in ethanol and deionized water for 30 min respectively, take them out and dry them at 50 °C for later use;

[0074] S3: Add the pretreated filter paper into the mother liquor, then add 2 mL of ethanol, ultrasonically shake for 30 min, take out the filter paper, and dry it at 30 °C;

[0075] S4 fixes the prepared filter paper on a non-absorbent substrate with double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0076] Comparative Example 6

[0077] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 6 comprises the following steps:

[0078] S1: Prepare plain paper: prepare a fixative (carboxymethyl cellulose) solution with a mass concentration of 0.1%, the preparation method is as follows: weigh 1g of carboxymethyl cellulose and dissolve it in deionized water, and make the volume to 1000mL. Cut the filter paper into a size of 10cm×10cm, immerse it in the solution, and dry it at 50℃ after it is fully infiltrated;

[0079] Preparation of S2 A solution: A solution contains 0.2% adsorbent (white carbon black), 0.2% color indicator (glycine methyl ester), 0.1% p-toluenesulfonic acid as a catalyst, and 0.02% suspending dispersant (alkylphenol polyoxyethylene ether) at a mass concentration. The preparation method is as follows: weigh 1g white carbon black, 1g glycine methyl ester, 0.5g p-toluenesulfonic acid, and 0.1g alkylphenol polyoxyethylene ether, dilute to 500mL with deionized water, and stir evenly;

[0080] S3: immersing the plain paper prepared in step S1 into solution A to fully wet it, and drying it at 50°C;

[0081] Preparation of S4 B solution: The B solution contains 0.2% of adsorbent (white carbon black), 0.2% of binder (polyvinyl alcohol) and 0.1% of suspending dispersant (alkylphenol polyoxyethylene ether) by mass concentration. The preparation method is as follows: weigh 1g of white carbon black, 20g of 5% polyvinyl alcohol aqueous solution and 0.5g of alkylphenol polyoxyethylene ether, dilute to 500mL with deionized water, and stir evenly;

[0082] S5: immersing the paper prepared in step S3 into solution B to fully wet the paper, and drying the paper at 50° C.;

[0083] S6 cut the test paper into strips with a width of 0.5 cm, stick it on a non-absorbent substrate, and cut it into test strips with a width of 0.5 cm to obtain the test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0084] Comparative Example 7

[0085] The preparation method of the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 7 comprises the following steps:

[0086] S1: Weigh 10 g of tert-butyl lysine, 4 g of potassium dihydrogen phosphate, 2 g of polypropylene glycol, and 2 g of N-carboxymethyl chitosan, add purified water to a total mass of 500 g, stir until dissolved, and mix well to obtain a solution;

[0087] S2 completely immerses the filter paper in the solution for 2 minutes. After the filter paper is completely soaked, put it into an oven and dry it at 50°C;

[0088] S3 cuts the dried filter paper and sticks it on a waterproof base cardboard using 3M double-sided tape to obtain a test paper for detecting the concentration of o-phthalaldehyde disinfectant.

[0089] Comparative Example 8

[0090] The difference from Example 1 is that an equal amount of polyvinyl alcohol is used to replace the N-carboxymethyl chitosan in step S3.

[0091] Comparative Example 9

[0092] The difference from Example 1 is that in step S3, the added amount of N-carboxymethyl chitosan is 55 g.

[0093] Comparative Example 10

[0094] The difference from Example 1 is that in step S3, the added amount of N-carboxymethyl chitosan is 0.4 g.

[0095] Comparative Example 11

[0096] The difference from Example 3 is that in step S3, analytically pure citric acid is not added.

[0097] The method of using the o-phthalaldehyde disinfectant concentration detection test paper of Examples 1-3 and Comparative Examples 1-3 and Comparative Examples 7-11 is as follows: immerse the filter paper part completely in the o-phthalaldehyde disinfectant, keep it for 3 seconds, gently shake off the excess disinfectant on the surface, place it horizontally, wait for 1 minute for color to develop, and compare it with the standard colorimetric card. When the test paper shows yellow, the o-phthalaldehyde disinfectant concentration of the standard colorimetric card can be corresponded according to the degree of yellow; when the test paper shows colorless, the o-phthalaldehyde disinfectant concentration is less than 0.3%.

[0098] The method of using the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 4 is as follows: take about 30 ml of o-phthalaldehyde disinfectant, adjust the pH to 6.5-7.5, put in the test paper, immerse the test paper completely for 2 seconds and then take it out, put the test paper in vertical contact with the paper towel, absorb the remaining liquid, place it horizontally on the paper towel for 80 seconds, observe the color change of the test paper, and use a known concentration of o-phthalaldehyde disinfectant for testing. When the test paper turns red evenly, it means that the concentration of the disinfectant is greater than 0.3%; when the test paper turns red unevenly or does not change color, it means that the concentration of the disinfectant is less than 0.3%.

[0099] The method of using the o-phthalaldehyde disinfectant concentration detection test paper of Comparative Example 5 is as follows: insert the test paper into the o-phthalaldehyde disinfectant to be tested for 3 seconds, take it out, gently shake it dry, start timing, and read the color after 90 seconds. If the test paper is original color (light blue), it means that the concentration of the disinfectant is less than 0.3%; if the color changes but the color is lighter and uneven, it means that the concentration of the disinfectant is 0.3%; if the color is obviously yellow-green and the color is uniform, it means that the concentration of the disinfectant is greater than 0.3%.

[0100] The method of using the o-phthalaldehyde disinfectant concentration test paper of comparative example 6 is as follows: completely immerse the color block at the end of the test paper in the o-phthalaldehyde disinfectant, take it out after keeping it for 2 seconds, immediately scrape off the excess disinfectant on the back of the test paper, place it horizontally to allow it to develop color naturally, and compare it with the standard colorimetric card after 20 seconds to read the concentration of the o-phthalaldehyde disinfectant. When the concentration is within the range of 0.3-0.6%, the test paper shows a uniform yellow color; when the solution concentration is less than 0.3%, it shows a light yellow color or no color.

[0101] The validity period of the test paper for detecting the concentration of phthalaldehyde disinfectant is tested by natural placement. 24 bottles of test paper samples are made for each experimental treatment, and a new bottle is opened every month to test the color development.

[0102] The test results of the o-phthalaldehyde disinfectant concentration test paper of Examples 1-3 and Comparative Examples 1-11 are shown in Table 1:

[0103] Table 1 Test results of o-phthalaldehyde disinfectant concentration test paper of Examples 1-3 and Comparative Examples 1-11

[0104]

[0105]

[0106] The actual color development of the test paper of the embodiment and comparative example is as follows Figure 1 shown.

[0107] Embodiments 1-3 show easily distinguishable color development effects through different concentrations of o-phthalaldehyde disinfectant: colorless, yellow and dark yellow. In actual use in hospitals, as long as the test strips of Embodiments 1-3 show yellow, it indicates that the concentration of the disinfectant is ≥3%, and high-level disinfection can be performed; as long as it shows colorless, it indicates that the concentration of the disinfectant is <3%, and the o-phthalaldehyde disinfectant needs to be replaced; and the validity period of the test strips of Embodiments 1-3 is 24 months, which is the same as the shelf life of the o-phthalaldehyde disinfectant product, thereby avoiding the phenomenon of the test strips expiring and becoming invalid during daily use.

[0108] Compared with the embodiment, in Comparative Examples 1-3, no film-forming agent was added, and the color development results did not correspond to the standard colorimetric card after a validity period of about 12 or 13 months. Although there is a stabilizer in the formula, the stabilizer used in the test strips currently on the market maintains a validity period of about 12 months and cannot reach a validity period of 24 months.

[0109] The color change principle of Comparative Example 4 is that the aldehyde group and sodium sulfite generate alkaline substances, and the pH is changed to control the color development. When the validity period is close to 12 months, the sodium sulfite is unstable and the alkaline substances generated are insufficient. When the concentration of the o-phthalaldehyde disinfectant does not reach the minimum effective concentration of 0.3%, it already shows uneven red.

[0110] The color change principle of Comparative Example 5 is that o-phthalaldehyde reacts with amino acids to generate a yellow substance, which reacts with blue-dyed filter paper to display green. The overall color change principle is the same as that of Examples 1-3, but the color development is unstable when the shelf life is close to 12 months.

[0111] The color change principle of Comparative Example 6 is the same as that of Examples 1-3, except that an organic acid is added to promote the reaction rate. However, the organic acid itself is unstable. When it is close to 12 months, the color change rate is the same as usual, and the color development effect is a transition from unqualified to qualified, from light yellow to yellow, and it is difficult to distinguish the o-phthalaldehyde concentration range corresponding to the color.

[0112] Comparative Example 7: After mixing liquid A and liquid B in Example 1, the chitosan in liquid B can prevent the color-developing substance in liquid A from being adsorbed on the filter paper, resulting in a light overall color and failure to form a film. The components on the filter paper cannot avoid denaturation such as oxidation under the protection of the film, and the product shelf life is less than 24 months.

[0113] The polyvinyl alcohol in Comparative Example 8 has good film-forming properties, but during the test process, when a small amount is added, it still shows a slow color development reaction and a shallow color development degree. The overall film formed is more solid, and it is difficult to achieve the required short color development time and obvious difference in color development results of different phthalaldehyde concentrations.

[0114] The amount of film-forming agent added in Comparative Example 9 is too much, and the overall color development effect and principle are similar to the reaction in Comparative Example 8 using polyvinyl alcohol as a film-forming agent.

[0115] The amount of the film-forming agent added in Comparative Example 10 is too low, and the overall color development effect and principle are similar to the results of Comparative Examples 1-3 without using a film-forming agent, and no film is formed.

[0116] In Comparative Example 11, citric acid was not added when preparing Solution B, which reduced the solubility of the film-forming agent in water and prevented it from being fully adsorbed on the filter paper. This resulted in the overall test results of the test paper being similar to those of Comparative Example 10, and it was difficult to form a complete film.

Claims

1. A method for preparing a test paper for detecting concentration of o-phthalaldehyde disinfectant, characterized in that: The following steps are involved: S1: dissolving a color developer, a color accelerator and a stabilizer in purified water to prepare a solution A, wherein the color developer is 0.1-10wt.%, the color accelerator is 0.1-10wt.%, and the stabilizer is 0.1-10wt.%; S2 completely immerses the filter paper in solution A for 1-2 minutes, and then dries it after it is completely soaked; S3: uniformly dissolving the film-forming agent in purified water to prepare 0.1-10wt.% of liquid B; S4: immerse the filter paper dried in step S2 into liquid B for 10-30 seconds and then dry; S5 cuts the dried filter paper and sticks it on the base cardboard to obtain the o-phthalaldehyde disinfectant concentration detection test paper.

2. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 1, characterized in that, In step S1, the color developer is an amino acid ester compound.

3. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 2, characterized in that, The color developer is one or more of glycine methyl ester, glycine ethyl ester, glycine tert-butyl ester, alanine methyl ester, alanine ethyl ester, alanine tert-butyl ester, lysine methyl ester, lysine ethyl ester, lysine tert-butyl ester, proline methyl ester, proline ethyl ester, proline tert-butyl ester, glutamate methyl ester, glutamate ethyl ester, glutamate tert-butyl ester, tyrosine methyl ester, tyrosine ethyl ester, tyrosine tert-butyl ester, serine methyl ester, serine ethyl ester, serine tert-butyl ester, tryptophan methyl ester, tryptophan ethyl ester, tryptophan tert-butyl ester, aspartic acid methyl ester, aspartic acid ethyl ester, aspartic acid tert-butyl ester, sarcosine methyl ester, sarcosine ethyl ester, sarcosine tert-butyl ester, valine methyl ester, valine ethyl ester and valine tert-butyl ester.

4. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 1, characterized in that, In step S1, the color development accelerator is one or more of hydrogen phosphate, hydrogen sulfate and carbonate.

5. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 1, characterized in that, In step S1, the stabilizer is one or more of ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, butylene glycol and polybutylene glycol.

6. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 1, characterized in that, In steps S2 and S4, the drying temperature is 40-60°C.

7. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 1, characterized in that, In step S3, the film-forming agent is one or both of chitosan and chitosan derivatives.

8. The preparation method of o-phthalaldehyde disinfectant concentration detection test paper as claimed in claim 7, characterized in that, The chitosan is one or more of chitosan with a deacetylation degree of 85%, chitosan with a deacetylation degree of 90%, and chitosan with a deacetylation degree of 95%. The chitosan derivative is one or two of N-carboxymethyl chitosan and carboxypropyl chitosan.

9. A test paper for detecting concentration of o-phthalaldehyde disinfectant, characterized in that: The method is prepared by the preparation method of the o-phthalaldehyde disinfectant concentration detection test paper as described in any one of claims 1 to 8.

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