Preparation method and detection method of polymer film for sodium dehydroacetate detection

Abstract

The invention relates to the technical field of food safety detection, and particularly discloses a preparation method and a detection method of a polymer film for sodium dehydroacetate detection. According to the preparation method, ammonium ferric sulfate is used as a colorimetric agent and packaged in a polymer film to prepare the ammonium ferric sulfate doped polymer film. The detection method comprises the following steps: S1, preparing an ammonium ferric sulfate doped polymer membrane; s2, cutting the prepared ammonium ferric sulfate doped polymer membrane into a proper size, and putting the cut polymer membrane into a centrifugal tube; s3, adding a to-be-detected solution containing sodium dehydroacetate with unknown concentration into the centrifugal tube, and carrying out a chromogenic reaction; and S4, obtaining the concentration of the sodium dehydroacetate according to color change caused by chromogenic reaction in the centrifugal tube after the sodium dehydroacetate is added. When the content of sodium dehydroacetate is detected, the operation is simple, no complex instrument is needed, the reaction time is short, and the detection result can be quickly obtained through visual observation with naked eyes.

Description

Technical Field

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

[0002] Sodium dehydroacetate (NADH) is a broad-spectrum, high-efficiency, low-toxic preservative. It is mainly used as a preservative to prevent microbial proliferation and extend the shelf life of food. It is widely used in food, beverages, 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, manifested as weakened liver and kidney function, and may cause neurological symptoms such as convulsions, tremors, and ataxia. At present, many countries and regions have strict regulatory restrictions on the use of sodium dehydroacetate. By detecting the content of sodium dehydroacetate, it can be ensured that the use of food additives meets safety standards and avoids potential risks to consumer health caused by excessive use. Commonly used methods for detecting sodium dehydroacetate include gas chromatography, microbiological method, titration method, liquid chromatography, micellar electrokinetic capillary chromatography and spectrophotometric method. These methods have problems such as complex operation, long time consumption, low sensitivity, low detection efficiency, etc., and their use in food is strictly limited. Therefore, the development of a rapid, accurate and sensitive detection method is crucial to ensure food safety and quality.

[0003] Colorimetry is a commonly used analytical method in chemical analysis. It is mainly based on the relationship between the color change of the sample solution and the concentration of the substance to be tested contained in the solution to quantitatively analyze the concentration of the substance to be tested. This method is simple to operate, easy to master, fast to detect, low cost, and the results are intuitively displayed. It is suitable for routine analysis and rapid on-site detection. At present, the colorimetric method commonly used for food safety detection is mainly nanogold colorimetry, which is relatively cumbersome to operate and relatively expensive. It is of great significance to develop a low-cost, simple-to-operate colorimetric method for food safety detection. Summary of the invention

[0004] In order to solve the problems of complex operation, long time consumption, low sensitivity and low detection efficiency in the prior art methods for detecting the content of sodium dehydroacetate, the present invention provides a preparation method and a detection method of a polymer film for detecting sodium dehydroacetate.

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

[0006] A method for preparing a polymer membrane for detecting sodium dehydroacetate comprises using ammonium ferric sulfate as a colorimetric agent and encapsulating the ammonium ferric sulfate in a polymer membrane to prepare an ammonium ferric sulfate-doped polymer membrane.

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

[0008] S1. preparing a polymer film doped with ammonium ferric sulfate;

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

[0010] S3, adding a test solution containing sodium dehydroacetate of unknown concentration into a centrifuge tube for color development reaction;

[0011] 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.

[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 of the sodium dehydroacetate to be tested can be read by comparing with the 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 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;

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

[0017] Preferably, in step S1, preparing the ammonium ferric sulfate-doped polymer film comprises the following steps:

[0018] Ammonium ferric sulfate was used as a colorimetric reagent and encapsulated in a polymeric membrane.

[0019] Preferably, 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.

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

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

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

[0023] 2. Simple operation, no need for complex instruments, fast response time, and the test results can be quickly obtained through 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 have been realized, such as naked eye observation and mobile phone photography. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0029] Figure 2 The present invention is a working curve diagram for obtaining the concentration of sodium dehydroacetate according to the RGB value. 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 colorimetric agent in a polymer film to prepare an ammonium ferric sulfate-doped polymer film, which can quickly detect sodium dehydroacetate in food additives.

[0034] Specifically, when the sodium dehydroacetate solution contacts the polymer film doped with ammonium ferric sulfate, the ammonium ferric sulfate and the sodium dehydroacetate generate a yellow complex Fe(NADH)3 complex. The greater the concentration of sodium dehydroacetate, the greater the concentration of the generated Fe(NADH)3 complex, and the darker the color of the solution. Intuitively, the concentration of sodium dehydroacetate can be used to quantitatively detect trace copper by colorimetry with the naked eye. In order to improve the accuracy of the measurement, the RGB value 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 has the following specific steps:

[0036] (1) using polyvinyl alcohol and chitosan as raw materials, encapsulating ammonium ferric sulfate 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 an unknown concentration of sodium dehydroacetate to the centrifuge tube in step (2). At this time, sodium dehydroacetate reacts with ammonium ferric sulfate to generate a yellow Fe(NADH)3 complex;

[0039] (4) quantitatively detecting trace amounts of sodium dehydroacetate by naked eye colorimetry, i.e., reading the concentration of sodium dehydroacetate to be measured by comparing it with a sodium dehydroacetate standard colorimetric card;

[0040] Further, the RGB value can be read directly by taking a photo with a mobile phone, or a working curve of the sodium dehydroacetate standard solution can be made by using an external standard method, an enzyme marker, and an ultraviolet absorption spectrum, and the sodium dehydroacetate concentration in the test solution can be obtained by the working curve.

[0041] Experimental example

[0042] Step (1)

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

[0044] Step (2)

[0045] 0.6 g of polyvinyl alcohol was added to 4.23 mL of deionized water and heated at 98°C for 20 min. After the polyvinyl alcohol was completely dissolved, the liquid was cooled to 50°C.

[0046] Step (3)

[0047] To the polyvinyl alcohol solution prepared in step (2), add 0.77 mL (1 mol / L) of ammonium ferric sulfate and 0.5 mL of the chitosan solution prepared in step (1), mix well, and heat to react at 50° C. for 2 h.

[0048] Step (4)

[0049] Add 0.6 mL (60 mg / mL) of polyvinyl pyrrolidone to the solution in step (3), and continue the reaction at 50° C. for 30 min.

[0050] Step (5)

[0051] After the reaction is completed, the formed viscous complex is evenly spread on a glass slide, and vacuum dried at 60° C. for 3 h for later use.

[0052] Step (6)

[0053] The prepared ammonium ferric sulfate-doped polymer film was cut into pieces with a size of 1 cm×1.5 cm and placed in a centrifuge tube. Then, 1 mL of a solution containing known different concentrations of sodium dehydroacetate was added, mixed, and reacted for 2 minutes.

[0054] Step (7)

[0055] Take pictures to obtain the color change of the solution after adding different concentrations of sodium dehydroacetate, and use a mobile phone to record the RGB value of the picture.

[0056] Step (8)

[0057] Repeat the above steps (1) to (7) to take pictures of mixed solutions with different concentrations of sodium dehydroacetate to obtain a standard colorimetric card and draw the following Figure 2 The working curves of samples with different concentrations of sodium dehydroacetate are shown. Figure 2 In the figure, the horizontal axis is the concentration of sodium dehydroacetate, and the vertical axis is the sum of the values ​​of the three RGB channels.

[0058] Step (9)

[0059] When measuring a sodium dehydroacetate sample of unknown concentration, according to the above steps (1) to (6), a solution after color development reaction is obtained, and the color of the sample of unknown concentration can be compared with the color of the standard colorimetric card obtained in step (8) by naked eyes. If the color of the sample of unknown concentration is the same as or similar to the color of a solution of a certain concentration in the standard colorimetric card, it is considered that the two concentrations are the same. If the color of the sample of unknown concentration after color development reaction is between the colors of the samples of two standard concentrations in the standard colorimetric card, it can be considered that the concentration of the sodium dehydroacetate of the unknown concentration 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, you can take a picture of the solution after the color reaction and use the mobile phone's built-in software to read the RGB value. Figure 2 The standard curve in the table above can be used to obtain the accurate concentration of sodium dehydroacetate.

[0062] The above-mentioned embodiments only express the specific implementation of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

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 is encapsulated in a polymer film to prepare an ammonium ferric sulfate-doped polymer film.

2. A method for detecting sodium dehydroacetate, characterized in that: The steps include: S1. preparing a polymer film doped with ammonium ferric sulfate; S2, cutting the prepared ammonium ferric sulfate-doped polymer film into a suitable size and placing it in a centrifuge tube; S3, adding a test solution containing sodium dehydroacetate of unknown concentration into a centrifuge tube for color development 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 sodium dehydroacetate detection method 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 with the sodium dehydroacetate standard colorimetric card.

4. The sodium dehydroacetate detection method 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 according to claim 2, wherein: In step S1, preparing an ammonium ferric sulfate-doped polymer film comprises the following steps: Ammonium ferric sulfate was used as a colorimetric reagent and encapsulated in a polymeric membrane.

6. The method for detecting sodium dehydroacetate according to claim 5, characterized in that: 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.

7. The method for detecting sodium dehydroacetate according to claim 6, characterized in that: 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 min.

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