A method for preparing a polymer film for detecting sodium dehydroacetate and a method for detecting sodium dehydroacetate

Abstract

The application relates to the technical field of food safety detection, and particularly discloses a preparation method and a detection method of a polymer film for detecting sodium dehydroacetate. In the preparation method, ferric ammonium sulfate is used as a colorimetric agent and is encapsulated in a polymer film to prepare a polymer film doped with ferric ammonium sulfate. The detection method comprises the following steps: S1, preparing the polymer film doped with ferric ammonium sulfate; S2, cutting the prepared polymer film doped with ferric ammonium sulfate into a proper size and placing the polymer film into a centrifugal tube; S3, adding a to-be-detected solution containing unknown-concentration sodium dehydroacetate into the centrifugal tube to perform a color reaction; and S4, obtaining the concentration of the sodium dehydroacetate according to the color change caused by the color reaction in the centrifugal tube after the sodium dehydroacetate is added. When the sodium dehydroacetate content is detected, the application has the advantages of simple operation, no need of complex instruments, fast reaction time, visual observation by naked eyes and rapid detection results.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of food safety detection, in particular to a preparation method and detection method of a polymer film for sodium dehydroacetate detection. BACKGROUND

[0002] Sodium dehydroacetate (NADH for short) is a broad-spectrum, high-efficiency, low-toxicity preservative, mainly used as a preservative to prevent microbial proliferation and extend the shelf life of food, and is widely used in food, beverage, feed, cosmetics, medicine and other fields. Studies have shown that long-term excessive consumption of sodium dehydroacetate may cause damage to the liver, kidneys and central nervous system, manifesting as functional weakening of the liver and kidneys, and possible neurological symptoms such as convulsions, tremors, and ataxia. Currently, many countries and regions have strict regulatory restrictions on the use of sodium dehydroacetate. By detecting the content of sodium dehydroacetate, it can ensure that the use of food additives meets safety standards, avoid potential risks to consumer health from excessive use, and help food producers comply with these regulations to avoid legal sanctions for violations. Common methods for detecting sodium dehydroacetate include gas chromatography, microbiological method, titration method, liquid chromatography, micellar electrokinetic capillary chromatography, and spectrophotometric method. These methods have the problems of complex operation, long time-consuming, low sensitivity, and low detection efficiency, and the use of food is strictly limited. Therefore, developing a rapid, accurate, and sensitive detection method is crucial for ensuring food safety and quality.

[0003] Colorimetry is a common analytical method in chemical analysis, which is mainly based on the relationship between the color change of the sample solution and the concentration of the measured substance in the solution to quantitatively analyze the concentration of the measured substance. This method is simple to operate, easy to master, fast to detect, low in cost, and the results are directly displayed, suitable for routine analysis and on-site rapid detection. Currently, the commonly used colorimetric method for food safety detection is the gold nanoparticle colorimetric method, which is relatively complex to operate and relatively high in cost. It is of great significance to develop and design a low-cost, simple-to-operate colorimetric method for food safety detection. SUMMARY

[0004] To solve the problems of complex operation, long time-consuming, low sensitivity, and low detection efficiency in the existing technology for detecting the content of sodium dehydroacetate, the present application provides a preparation method and detection method of a polymer film for sodium dehydroacetate detection.

[0005] The technical solution adopted by the present application is:

[0006] A preparation method of a polymer film for sodium dehydroacetate detection, which uses ammonium ferric sulfate as a colorimetric agent and encapsulates it in a polymer film to prepare an ammonium ferric sulfate-doped polymer film.

[0007] A method for detecting sodium dehydroacetate, comprising the following steps:

[0008] S1, preparing an ammonium ferric sulfate doped polymer film;

[0009] S2, cutting the prepared ammonium ferric sulfate doped polymer film to a suitable size and placing it in a centrifuge tube;

[0010] S3, adding a solution containing unknown concentration of sodium dehydroacetate to be detected into the centrifuge tube to carry out a color reaction;

[0011] S4, obtaining the concentration of sodium dehydroacetate according to the color change caused by the color reaction in the centrifuge tube after adding sodium dehydroacetate.

[0012] Preferably, in step S4, the step of obtaining the concentration of sodium dehydroacetate is as follows:

[0013] According to the color change, the concentration value of the sodium dehydroacetate to be detected is read by comparing with a sodium dehydroacetate standard colorimetric card.

[0014] Preferably, in order to further improve the detection accuracy, in step S4, the step of obtaining the concentration of sodium dehydroacetate is as follows:

[0015] After the color reaction is completed, a photo of the reactants in the centrifuge tube after the color reaction is taken, and the RGB value of the photo is read;

[0016] The concentration of sodium dehydroacetate is obtained from the working curve according to the RGB value.

[0017] Preferably, in step S1, the ammonium ferric sulfate doped polymer film is prepared, comprising the following steps:

[0018] Ammonium ferric sulfate is used as a colorimetric agent and is encapsulated in a polymer film.

[0019] Preferably, in step S2, the size of the cut polymer film is 1 cm x 1.5 cm, and the volume of the centrifuge tube is 2 mL.

[0020] Preferably, in step S3, the amount of the solution containing unknown concentration of sodium dehydroacetate to be detected added is 1 mL, and the color reaction time is 2 min.

[0021] The beneficial effects of the present application are:

[0022] 1. The synthesis method of the ammonium ferric sulfate doped polymer film is simple, and the raw material cost is low;

[0023] 2. The operation is simple, no complex instruments are needed, the reaction time is fast, the detection result can be quickly obtained by visual observation with the naked eye;

[0024] 3. The amount of sample required for testing is small, and the experiment can be carried out in a centrifuge tube;

[0025] 4. Since it can be carried out in a centrifuge tube, it is easy to carry and can be used for on-site testing;

[0026] 5. Due to the short response time, multiple groups of samples can be tested in a short time;

[0027] 6. A variety of color reading methods are realized, such as naked eye observation and mobile phone photography. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A physical picture of the polymer film prepared according to the present invention;

[0029] Figure 2 This is a working curve diagram for obtaining the concentration of sodium dehydroacetate based on RGB values ​​in the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0031] Example

[0032] The present invention adopts the principle of colorimetry to detect sodium dehydroacetate in food additives:

[0033] The invention adopts ammonium ferric sulfate as a colorimetric agent and encapsulates the ammonium ferric sulfate-doped polymer film in a polymer film to quickly detect sodium dehydroacetate in food additives.

[0034] Specifically, when a sodium dehydroacetate solution comes into contact with an ammonium ferric sulfate-doped polymer film, the ammonium ferric sulfate and the sodium dehydroacetate form a yellow complex, Fe(NADH)3. The higher the concentration of sodium dehydroacetate, the higher the concentration of the Fe(NADH)3 complex generated, and the darker the color of the solution. Intuitively, the concentration of sodium dehydroacetate can be quantitatively detected using colorimetry with the naked eye to measure trace amounts of sodium dehydroacetate. To improve measurement accuracy, the RGB values ​​can also be read by taking a photo with a mobile phone.

[0035] The present invention uses ammonium ferric sulfate as a colorimetric agent and encapsulates it in a polymer film to prepare an ammonium ferric sulfate-doped polymer film. The method for detecting the concentration of sodium dehydroacetate in food additives by colorimetry comprises the following steps:

[0036] (1) Using polyvinyl alcohol and chitosan as raw materials, ammonium ferric sulfate is encapsulated in a film to prepare an ammonium ferric sulfate-doped polymer film;

[0037] (2) cutting the prepared ammonium ferric sulfate-doped polymer film into a suitable size and placing it in a centrifuge tube;

[0038] (3) Add 1 mL of the test solution containing unknown concentration of sodium dehydroacetate into the centrifuge tube in step (2), at this time, sodium dehydroacetate reacts with ferric ammonium sulfate to form yellow Fe(NADH)3 complex;

[0039] (4) Quantitatively detect trace amount of sodium dehydroacetate by naked eye colorimetry, i.e. read the concentration value of the test sodium dehydroacetate by comparison with sodium dehydroacetate standard colorimetric card;

[0040] Further or directly take a photo by mobile phone to further read the RGB value or use external standard method to make a working curve of sodium dehydroacetate standard solution by enzyme label instrument and ultraviolet absorption spectrum, and then calculate the concentration of sodium dehydroacetate in the test solution by the working curve.

[0041] Experimental Example

[0042] Step (1)

[0043] Weigh 0.1 g of chitosan in a glass bottle, and then add 5 mL of deionized water and 0.15 mL of 1 mol / L acrylic acid in sequence, stir at room temperature for 48 h, and reserve.

[0044] Step (2)

[0045] Add 0.6 g of polyvinyl alcohol into 4.23 mL of deionized water, and heat at 98 o C for 20 min. After the polyvinyl alcohol is completely dissolved, cool the liquid to 50 o C.

[0046] Step (3)

[0047] Add 0.77 mL of 1 mol / L ferric ammonium sulfate and 0.5 mL of chitosan solution prepared by step (1) into the polyvinyl alcohol solution prepared in step (2), mix uniformly, and heat at 50 o C for 2 h.

[0048] Step (4)

[0049] Add 0.6 mL of 60 mg / mL polyvinylpyrrolidone into the solution in step (3), and continue to react at 50 o C for 30 min.

[0050] Step (5)

[0051] After the reaction is completed, uniformly spread the formed viscous compound on a glass sheet, and vacuum dry at 60 o C for 3 h, and reserve.

[0052] Step (6)

[0053] The prepared ammonium iron sulfate doped polymer film was cut into a size of 1 cm x 1.5 cm and placed in a centrifuge tube. Then 1 mL of a solution containing a known different concentration of sodium dehydroacetate was added, mixed, and reacted for 2 min.

[0054] Step (7)

[0055] Pictures of the color change of the solution after adding sodium dehydroacetate of different concentrations were taken, and the RGB values of the pictures were recorded by a mobile phone.

[0056] Step (8)

[0057] The pictures of the mixed solution of different concentrations of sodium dehydroacetate were taken repeatedly according to the above steps (1) to (7) to obtain a standard color chart, and a working curve of the samples of different concentrations of sodium dehydroacetate was drawn as shown in Figure 2 . Figure 2 In the figure, the abscissa is the concentration of sodium dehydroacetate, and the ordinate is the numerical value of the three channels of RGB.

[0058] Step (9)

[0059] When determining the unknown concentration of sodium dehydroacetate sample, the color reaction solution is obtained according to the above steps (1) to (6), and the color of the unknown concentration sample can be compared with the color of the standard color chart obtained in step (8) by naked eye. If the color of the unknown concentration sample is the same as or similar to the color of the solution of a certain concentration in the standard color chart, it is considered that the two concentrations are the same, and if the color of the color reaction solution of the unknown concentration sample is between the colors of the color reaction solutions of two standard concentrations in the standard color chart, it is considered that the concentration of sodium dehydroacetate in the unknown sample is between the above two standard concentrations.

[0060] Step (10)

[0061] In order to further obtain the accurate concentration of sodium dehydroacetate in the unknown sample, the picture of the color reaction solution can be taken, the RGB value can be read by the software of the mobile phone, and the accurate concentration of sodium dehydroacetate can be obtained according to the standard curve in Figure 2 .

[0062] The above-described embodiments only express the specific implementation of the present application, which is described in detail and specifically, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which are within the protection scope of the present application.

Claims

1. A method for preparing a polymer film for detecting sodium dehydroacetate, characterized in that: Ammonium ferric sulfate is used as a colorimetric agent and encapsulated in a polymer film to prepare an ammonium ferric sulfate-doped polymer film, comprising the following steps: S1. Weigh chitosan into a glass bottle, add deionized water and acrylic acid in sequence, stir at room temperature, and set aside; S2. Add polyvinyl alcohol to deionized water, heat, and cool the liquid to 50° C. after the polyvinyl alcohol is completely dissolved; S3, adding ammonium ferric sulfate and the chitosan solution prepared in step S1 to the polyvinyl alcohol solution prepared in step S2, mixing evenly, and heating the mixture at 50° C. for 2 h; S4, adding polyvinyl pyrrolidone to the solution in step S3, and continuing the reaction at 50°C for 30 min; S5. After the reaction is completed, the formed viscous complex is evenly spread on a glass slide, vacuum dried and set aside.

2. The method for detecting sodium dehydroacetate using a polymer film according to claim 1, wherein The steps include: S1. preparing an ammonium ferric sulfate-doped polymer film; S2. Cutting the prepared ammonium ferric sulfate-doped polymer film into a suitable size and placing it into a centrifuge tube; S3. Add the test solution containing sodium dehydroacetate of unknown concentration into the centrifuge tube to perform a color reaction; S4. The concentration of sodium dehydroacetate is obtained according to the color change caused by the color development reaction in the centrifuge tube after the addition of sodium dehydroacetate.

3. The method for detecting sodium dehydroacetate using a polymer film according to claim 2, wherein: In step S4, the steps of obtaining the concentration of sodium dehydroacetate are as follows: According to the color change, the concentration of the sodium dehydroacetate to be tested can be read by comparing it with the sodium dehydroacetate standard colorimetric card.

4. The method for detecting sodium dehydroacetate using a polymer film according to claim 2, wherein: In step S4, the steps of obtaining the concentration of sodium dehydroacetate are as follows: After the color development reaction is completed, take a photo of the reactants in the centrifuge tube after the color development reaction and read the RGB value of the photo; The concentration of sodium dehydroacetate was obtained from the working curve according to the RGB value.

5. The method for detecting sodium dehydroacetate using a polymer film according to claim 4, wherein: In step S2, the size of the cut polymer film is 1 cm × 1.5 cm, and the volume of the centrifuge tube is 2 mL.

6. The method for detecting sodium dehydroacetate using a polymer film according to claim 5, wherein: In step S3, the amount of the test solution containing sodium dehydroacetate of unknown concentration added is 1 mL, and the color development reaction time is 2 minutes.

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