Method for rapidly identifying auramine in durian peel

Abstract

The invention discloses a method for rapidly identifying auramine in durian peel, which comprises the following steps: S1, selecting durian as a sample, and selecting an area at the deepest yellow part of the sample as a sampling area; s2, adhering acetonitrile to a wiping tool, wiping and sampling in the sampling area of the sample, soaking the wiping tool in acetonitrile, and shaking; s3, after the step S2 is completed, if the chromaticity of the test solution is greater than 150 black units, adding a strong acid solution, slightly shaking, observing color change, and if yellow becomes light or fades, judging that the sample contains alkaline bright yellow; if the chromaticity of the test solution is less than or equal to 150 black units, entering the step S4; and S4, scanning the acetonitrile solution at 191-600nm by using an ultraviolet visible spectrophotometer, and if an absorption peak exists at 440nm, judging that the sample contains the auramine. According to the method, whether the durian skin is subjected to alkaline bright yellow treatment or not is rapidly and preliminarily judged through an acid-adding visual method or a spectrophotometer method, the customs clearance efficiency of the durian is greatly improved, and the retention loss of goods is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food safety, and particularly relates to a rapid identification method of basic flavine in durian peel. BACKGROUND

[0002] Basic flavine is a yellow industrial dye, which is mainly used for dyeing various objects. Basic flavine has irritancy to human skin mucosa, can cause various symptoms, and can damage human kidney, liver and even cause cancer in long-term excessive consumption. Basic flavine is listed as a 2B carcinogen by the World Health Organization, and has been listed as a non-food substance in China. Some unscrupulous businessmen will use basic flavine to dye durians to improve the color of durian peel. At present, the detection methods for basic flavine on the surface of durian mainly include high performance liquid chromatography and liquid chromatography-mass spectrometry (LC-MS). The advantages of these detection methods are high sensitivity, and multiple components can be detected at the same time. However, special equipment is needed, and professional personnel are needed to operate, and the detection time is relatively long. In addition, sampling and sample preparation are also troublesome, and the detection efficiency is difficult to improve. The import volume of durians in China is large, in order to avoid the disturbance of inferior or illegally treated durians in the market, the customs needs to carry out sampling inspection on imported durians. The existing detection efficiency is difficult to improve, and it is easy to cause goods to be detained and cause losses. Therefore, the customs needs to improve the detection efficiency of imported durians while ensuring the accuracy of the detection results, and shorten the detection time. It is necessary to improve the existing detection method. SUMMARY

[0003] To solve the above technical problems, the purpose of the present application is to provide a rapid identification method of basic flavine in durian peel, which can quickly and preliminarily determine whether the surface of durian is treated with basic flavine by acid addition visual method or spectrophotometer method, effectively improve the supervision efficiency, greatly improve the durian customs clearance efficiency, and reduce the loss caused by goods detention.

[0004] To achieve the above-mentioned purpose of the application, the technical solutions adopted by the present application are as follows:

[0005] A rapid identification method of basic flavine in durian peel is as follows:

[0006] S1, one or more durians with yellow or dark yellow skin are selected as test samples, and the area with the deepest yellow color of the sample is selected as the sampling area;

[0007] S2, an acetone is adhered to a wiping tool, the sampling area of the sample is wiped, the wiping tool is immersed in acetone and shaken, the wiping tool is taken out to wipe other sampling areas, then the wiping tool is immersed in acetone again and shaken, and the operation is repeated until the sampling on all sampling areas of the durian sample skin is completed. Finally, the acetone in the wiping tool is completely squeezed out when the wiping tool is taken out, and a test solution is obtained;

[0008] S3, after completing step S2, compare the test solution with the standard colorimetric solution, and observe the color of the test solution;

[0009] If the color of the test solution is >150 Hazen units, add a strong acid solution, observe the color change after gently shaking, if the yellow color becomes lighter or fades, it is judged that the sample contains basic yellow; if there is no color change, it means that the sample does not contain basic yellow;

[0010] If the color of the test solution is ≤150 Hazen units, go to step S4;

[0011] S4, the test solution obtained after sampling in step S2 is scanned by ultraviolet visible spectrophotometer at 191-600nm, and it is observed whether there is an absorption peak of acetonitrile solution at 440nm;

[0012] If there is an absorption peak at 440nm, it is judged that the sample contains basic yellow;

[0013] If there is no absorption peak at 440nm, it is judged that the sample does not contain basic yellow.

[0014] Preferably, in step S1, the number of sampling areas is ≥1.

[0015] Preferably, in step S1, the area of each sampling area is ≥25cm 2 .

[0016] More preferably, the length and width of the sampling area are both ≥5cm.

[0017] Preferably, in step S2, the wiping tool includes a cotton swab.

[0018] More preferably, in step S2, 5mL of acetonitrile is added to a 10mL stoppered colorimetric tube, the cotton swab is inserted into the stoppered colorimetric tube to stick acetonitrile, and the sampling area of the durian sample is wiped. After wiping, the cotton swab is placed in the stoppered colorimetric tube for soaking and gently shaken, then the cotton swab is taken out and the excess acetonitrile is squeezed out on the tube wall, the same cotton swab is used to wipe the same sampling area or other sampling areas, and each time the wiping is completed, the cotton swab is soaked in acetonitrile and shaken, finally the cotton swab is taken out and the acetonitrile in the cotton swab is squeezed out, obtaining the test solution.

[0019] Preferably, in step S2, when the wiping tool is first soaked in acetonitrile, the shaking time is 4-6s.

[0020] More preferably, when the wiping tool is subsequently soaked in acetonitrile, the shaking time is ≥10s.

[0021] Preferably, in step S2, the number of times each sampling area is wiped is 1-2 times.

[0022] Preferably, in step S3, the strong acid comprises concentrated sulfuric acid.

[0023] Advantages:

[0024] The present application can quickly and preliminarily determine whether the durian skin is treated with alkaline tender yellow by adding acid visual method or spectrophotometer method. For durians that are not treated with alkaline tender yellow, after determination by adding acid visual method or spectrophotometer method, there is no need to send samples to the laboratory for detection, which effectively improves the supervision efficiency, greatly improves the durian customs clearance efficiency, and reduces the loss of goods detention.

[0025] The rapid identification method of the present application is simple to operate and can be used for on-site screening after simple training. It has the advantages of wide application range and can be combined with traditional laboratory detection and popularized in port, supermarket, and agricultural market scenes. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The scanning diagram of the blank matrix in Example 2 is shown

[0027] Figure 2 The scanning diagram of the durian skin alkaline tender yellow standard addition (50 μg / kg) in Example 2 is shown

[0028] Figure 3 The scanning diagram of the durian skin alkaline tender yellow standard addition (70 μg / kg) in Example 2 is shown

[0029] Figure 4 The scanning diagram of the durian skin alkaline tender yellow standard addition (100 μg / kg) in Example 2 is shown. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the specific embodiments of the present application will be described below with reference to the drawings. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creative labor, and other embodiments can also be obtained.

[0031] The present application provides a rapid identification method for alkaline tender yellow in durian skin, as follows:

[0032] S1, one or more durians with yellow or dark yellow skin are selected as test samples, and the area with the deepest yellow color of the sample is selected as the sampling area, and the number of sampling areas is ≥1; preferably, the area of the sampling area is ≥25 cm 2 More preferably, the length and width of the sampling area are both ≥5 cm.

[0033] S2, the wiping tool is stuck with acetonitrile, and the sample area is wiped; the wiping tool is immersed in acetonitrile and shaken, the wiping tool is taken out to wipe the same sampling area or wipe other sampling areas, and then the wiping tool is immersed in acetonitrile again and shaken, and the operation is repeated until sampling of all sampling areas on the surface of the durian sample is completed; and finally, when the wiping tool is taken out, the acetonitrile in the wiping tool is completely squeezed out to obtain a test solution;

[0034] S3, after step S2 is completed, the test solution is compared with a standard colorimetric solution, and the color of the test solution is observed;

[0035] If the test solution is obviously yellow, for example, the color of the test solution is greater than 150 Hazen units, a strong acid solution is added, the color change is observed after gentle shaking, if the yellow color becomes lighter or fades, it is judged that the sample contains basic yellow; if there is no color change, it means that the sample does not contain basic yellow;

[0036] If the color of the test solution is less than or equal to 150 Hazen units, step S4 is entered;

[0037] S4, the test solution obtained after sampling in step S2 is scanned by a UV-visible spectrophotometer at 191-600 nm, and whether the acetonitrile solution has an absorption peak at 440 nm is observed;

[0038] If there is an absorption peak at 440 nm, it is judged that the sample contains basic yellow;

[0039] If there is no absorption peak at 440 nm, it is judged that the sample does not contain basic yellow.

[0040] The step S3 of the present application is an acid addition visual method, which can be completed within 2 minutes, and the principle is that the acetonitrile solution of basic yellow fades after the addition of a strong acid; the step S4 is a spectrophotometer method, and the detection time is generally within 10 minutes, and the principle is that the acetonitrile solution of basic yellow has an absorption peak at 440 nm under ultraviolet-visible light wave scanning. For durians whose surface is not treated with basic yellow, if the solution dissolved in acetonitrile after wiping is yellow, it can be judged as not containing basic yellow after visual judgment after adding acid, and the detection can be completed within 2 minutes. Even if the yellow color of the test solution is not easy to be recognized by the naked eye, that is, the color of the test solution is between 50 and 150 Hazen units, the detection can also be completed within 10 minutes by the spectrophotometer method. Compared with the traditional liquid chromatography or liquid chromatography-mass spectrometry method which needs more than 2 days, the detection time of the present application is greatly shortened.

[0041] The application can combine visual judgment, rapid detection and laboratory accurate detection, which is equivalent to adding pre-fast identification operation before laboratory detection, reducing the workload of laboratory detection, and improving the detection efficiency. The application can preliminarily determine whether the durian skin is treated by alkaline tender yellow through the acid-adding visual method or the spectrophotometer method. The durian that is not treated by alkaline tender yellow does not need to be sent to the laboratory for detection after being determined by the acid-adding visual method or the spectrophotometer method, which effectively improves the supervision efficiency. For the customs, the durian customs clearance efficiency can be greatly improved, and the loss of goods detention can be reduced.

[0042] The fast identification operation of the application is simple, and can be detected after simple training. The application can be used in combination with traditional laboratory detection, and can be popularized to scenes such as ports, supermarkets, and farmers' markets.

[0043] The standard colorimetric solution related in the application is made by the existing conventional method, and the specific preparation steps are as follows:

[0044] Since the colorimetric solution prepared by potassium chloroplatinate and cobalt chloride hexahydrate is similar to the yellow color tone generated by wiping the durian skin with acetonitrile, according to the preparation of the colorimetric solution in GB / T 605-2006 'General method for colorimetric determination of chemical reagents', 0.100g of cobalt chloride hexahydrate and 0.124g of potassium chloroplatinate are weighed into a beaker, dissolved with 10mL of hydrochloric acid and an appropriate amount of water, transferred to a 100mL volumetric flask, diluted with water to constant volume, shaken well, and a standard colorimetric solution with a colorimetric value of 500 Hazen units is prepared. 0.5mL, 1.0mL, 1.5mL and 2.0mL of the standard colorimetric solution with a colorimetric value of 500 Hazen units are taken into 10mL stoppered colorimetric tubes, and 4.5mL, 4.0mL, 3.5mL and 3.0mL of water are added respectively, shaken well, and standard colorimetric solutions with colorimetric values of 50 Hazen units, 100 Hazen units, 150 Hazen units and 200 Hazen units are prepared.

[0045] Five alkaline tender yellow negative samples (durian skin) of common durian varieties such as Cat Mountain King, Black Thorn, Golden Pillow, Ganyao and Sultan are selected, and the parts with deeper yellow skin are selected. A part with an area of at least 5cm*5cm (25cm 2 ) is selected as the wiping area. 5mL of acetonitrile is added to a 10mL stoppered colorimetric tube, a cotton swab is inserted into the colorimetric tube to stick acetonitrile, and the selected durian skin area is repeatedly wiped. After wiping, the cotton swab is soaked in the colorimetric tube and shaken gently for about 5s, the cotton swab is taken out and the excess acetonitrile is squeezed out on the colorimetric tube wall, the cotton swab is repeatedly wiped on the same area for 1-2 times, each time the cotton swab is soaked in the colorimetric tube and shaken for at least 10s, finally the cotton swab is clamped out with tweezers and squeezed dry, and a negative sample acetonitrile wiping solution is obtained.

[0046] The negative sample acetonitrile wiping solution obtained above is visually compared with a standard colorimetric solution, and it is found that the colorimetric value of the negative sample acetonitrile solution is between 50 Hazen units and 150 Hazen units, so 150 Hazen units is selected as the boundary, and the sample with a colorimetric value greater than 150 Hazen units is identified by the acid-adding visual method of the present application, and the sample with a colorimetric value less than or equal to 150 Hazen units is identified by the spectrophotometer method of the present application.

[0047] Preferably, in step S2, the wiping tool comprises a cotton swab, and other materials capable of adsorbing acetonitrile and not dissolving or reacting with acetonitrile can also be used as the wiping tool of the present application, and the present application will not be repeated here.

[0048] More preferably, in step S2, 5 mL of acetonitrile is added to a 10 mL stoppered colorimetric tube, the cotton swab is inserted into the stoppered colorimetric tube to stick the acetonitrile, and the sample area of the durian sample is repeatedly wiped. After wiping, the cotton swab is placed in the stoppered colorimetric tube for soaking and gently shaken, then the cotton swab is taken out and the excess acetonitrile is squeezed out of the tube wall, the same cotton swab is used to repeatedly wipe the same sample area or other sample areas, and after each wiping, the cotton swab is soaked in acetonitrile and shaken, and finally the cotton swab is taken out and the acetonitrile in the cotton swab is squeezed dry to prepare a test solution.

[0049] Preferably, in step S2, when the wiping tool is first soaked in acetonitrile, the shaking time is 4-6 s, for example, the shaking time is 5 s. More preferably, when the wiping tool is subsequently soaked in acetonitrile, the shaking time is ≥10 s.

[0050] Preferably, in step S2, each sample area is wiped 1-2 times.

[0051] Preferably, in step S3, the strong acid comprises concentrated sulfuric acid.

[0052] Preferably, in steps S3 and S4, when it is determined that the sample contains basic auramine, the problem sample is finally detected and confirmed by liquid chromatography-mass spectrometry.

[0053] The technical solutions of the present application are described in detail below with specific examples.

[0054] Example 1

[0055] A negative sample (durian peel) was used as a matrix, and 25 cm 2 (about 30 g) of epidermis was taken for four groups of experiments. Among them, the first group of durian peel matrix was not treated, serving as a blank control group, and the last three groups of negative samples (durian peel) were tested for auramine O recovery, the second group added 600 μg / kg, the third group added 700 μg / kg, and the fourth group added 800 μg / kg.

[0056] Four groups of durian peel matrix were detected by acid addition visual method, and the steps were as follows:

[0057] 5 mL of acetonitrile was added to a 10 mL stoppered colorimetric tube, and a cotton swab was inserted into the stoppered colorimetric tube to stick acetonitrile, and the durian peel matrix was repeatedly wiped, and after wiping, the cotton swab was placed in the stoppered colorimetric tube for soaking and gently shaking for about 5 s, then the cotton swab was taken out and the excess acetonitrile was squeezed out on the tube wall, and the same cotton swab was used to wipe the durian peel matrix again, and after each wiping, the cotton swab was soaked in acetonitrile and shaken for at least 10 s, and finally the cotton swab was taken out and the acetonitrile in the cotton swab was squeezed dry;

[0058] Then 3-5 drops of concentrated sulfuric acid were added along the colorimetric tube wall with a glass dropper, gently shaken, and the color change of the solution was observed and recorded. Each group of durian peel matrix was tested six times according to the above method, and the repeatability test results are shown in Table 1.

[0059] Three groups of experiments were performed with 5 mL (about 3.9 g) of acetonitrile respectively. Three groups of acetonitrile were tested for alkaline litmus standard addition recovery, the first group was added at a level of 80 μg / kg, the second group was added at a level of 100 μg / kg, and the third group was added at a level of 150 μg / kg.

[0060] The acetonitrile group was set to verify that the addition of acid can cause the discoloration of alkaline litmus in the acetonitrile solution, and the minimum concentration of alkaline litmus in the acetonitrile solution was verified without the interference of durian samples.

[0061] The discoloration of each group of acetonitrile solution was tested: 5 mL of acetonitrile solution was added to a 10 mL stoppered colorimetric tube, concentrated sulfuric acid was taken with a glass dropper, 3-5 drops were carefully added along the colorimetric tube wall, gently shaken, and the color change of the solution was observed and recorded. Each group of acetonitrile solution was tested six times according to the above method, and the repeatability test results are shown in Table 1.

[0062] Table 1 Test results of acid addition visual method

[0063]

[0064] Based on Table 1, the minimum concentration of alkaline litmus in the acetonitrile solution is 100 μg / kg without the interference of durian samples, and the detection limit of the acid addition visual method of the present application is 700 μg / kg.

[0065] Example 2

[0066] A negative sample (durian peel) was used as the matrix, and 25 cm 2Four groups of experiments were carried out on the epidermis of about 30 g of the durian peel. Among them, the first group of durian peel matrix was not treated, serving as a blank control group, and the last three groups were respectively subjected to the recovery test of the negative sample (durian peel), the second group was added at a level of 50 μg / kg, the third group was added at a level of 70 μg / kg, and the fourth group was added at a level of 100 μg / kg.

[0067] The four groups of durian peel matrix were detected by the spectrophotometer method, and the steps were as follows:

[0068] 5 mL of acetonitrile was added to a 10 mL stoppered colorimetric tube, a cotton swab was inserted into the stoppered colorimetric tube to stick acetonitrile, and the durian peel matrix was repeatedly wiped, after wiping, the cotton swab was placed in the stoppered colorimetric tube to soak and gently shake for about 5 s, then the cotton swab was taken out and the excess acetonitrile was squeezed out on the tube wall, and the same cotton swab was used to repeatedly wipe the durian peel matrix, and after each wiping, the cotton swab was soaked in acetonitrile and shaken for at least 10 s, finally the cotton swab was taken out and the acetonitrile in the cotton swab was squeezed dry;

[0069] The acetonitrile solution was scanned by the ultraviolet-visible light spectrophotometer at 191-600 nm, and whether the acetonitrile solution had an absorption peak at 440 nm was observed and recorded. Each group of durian peel matrix was tested six times according to the above method, and the repeatability test results are shown in Table 2.

[0070] Table 2 Repeatability test results of the spectrophotometer method

[0071]

[0072] Based on Table 2, the detection limit of the spectrophotometer method of the present application is 70 μg / kg.

[0073] The acetonitrile solution was scanned by the ultraviolet-visible light spectrophotometer at 191-600 nm, and whether the acetonitrile solution had an absorption peak at 440 nm was observed and recorded. Each group of durian peel matrix was tested six times according to the above method, and the repeatability test results are shown in Table 2. Figure 1 Figure 2 Figure 3 Figure 4 Figures 1-4 As can be seen from Table 2, the detection limit of the spectrophotometer method of the present application is 70 μg / kg, and for the case of adding 100 μg / kg of basic light yellow, the spectrophotometer method can be obviously detected.

[0074] ​​​​The above has carried out the detailed elaboration to the example provided by the application. The principle and implementation mode of the application are described by applying specific examples in this paper, and the above example description is only used to help understand the core idea of the application. It should be pointed out that for ordinary skilled person in the art, without departing from the principle of the application, the application can be improved and modified, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A method for rapid identification of basic tender yellow in durian peel, characterized by, As follows: S1, select one or more durians as samples, and select an area at the deepest yellow part of the sample as a sampling area; S2, stick the wiping tool with acetonitrile, wipe the sampling area of the sample, immerse the wiping tool in acetonitrile and shake, take out the wiping tool to wipe other sampling areas, then immerse the wiping tool in acetonitrile again and shake, repeat the operation until sampling of all sampling areas on the surface of the durian sample is completed, and finally take out the wiping tool and squeeze out the acetonitrile in the wiping tool completely to obtain a test solution; S3, after completing step S2, compare the test solution with a standard colorimetric solution, and observe the color of the test solution; If the color of the test solution is >150 Hazen units, add a strong acid solution, shake gently and observe the color change, if the yellow color becomes lighter or fades, it is judged that the sample contains basic yellow; If there is no color change, it means that the sample does not contain basic yellow; If the color of the test solution is ≤150 Hazen units, proceed to step S4; S4, scan the acetonitrile solution obtained after sampling in step S2 by ultraviolet-visible spectrophotometer at 191-600 nm, and observe whether there is an absorption peak at 440 nm; If there is an absorption peak at 440 nm, it is judged that the sample contains basic yellow; If there is no absorption peak at 440 nm, it is judged that the sample does not contain basic yellow.

2. The method of rapid identification of basic tender yellow in jackfruit peel according to claim 1, characterized in that, In step S1, the number of sampling areas is ≥1.

3. The method of claim 1, wherein the method is characterized by, In step S1, the area of each sampling area is > 25 cm 2 .

4. The method of rapid identification of basic tender yellow in jackfruit peel according to claim 3, characterized in that, The length and width of the sampling area are both ≥5 cm.

5. The method of rapid identification of basic flavine in jackfruit peel according to any one of claims 1-4, characterized in that, In step S2, the wiping tool includes a cotton swab.

6. The method of rapid identification of basic tender yellow in jackfruit peel according to claim 5, characterized in that, In step S2, 5 mL of acetonitrile is added to a 10 mL stoppered colorimetric tube, the cotton swab is inserted into the stoppered colorimetric tube to stick acetonitrile, the sampling area of the durian sample is wiped, and after wiping, the cotton swab is immersed in the stoppered colorimetric tube and shaken, then the cotton swab is taken out and the excess acetonitrile is squeezed out on the tube wall, the same cotton swab is used to repeat wiping the same sampling area or other sampling areas, and after each wiping, it is immersed in acetonitrile and shaken, finally the cotton swab is taken out and the acetonitrile in the cotton swab is squeezed out to obtain a test solution.

7. The method of rapid identification of basic jaundice in jackfruit peel according to claim 1, characterized in that, In step S2, when the wiping tool is first immersed in acetonitrile, the shaking time is 4-6 s.

8. The method of rapid identification of basic tender yellow in jackfruit peel according to claim 7, characterized in that, In subsequent immersion of the wiping tool in acetonitrile, the shaking time is ≥10 s.

9. The method of rapid identification of basic tender yellow in jackfruit rind according to claim 1, characterized in that, In step S2, the number of times of wiping each sampling area is 1-2 times.

10. The method of rapid identification of basic tender yellow in jackfruit rind according to claim 1, characterized in that, In step S3, the strong acid includes concentrated sulfuric acid.

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