Rapid nitrite screening kit and use method thereof

Abstract

The invention discloses a rapid nitrite screening kit and a use method thereof, and relates to the field of detection kits.The kit comprises a reagent bottle A, a reagent bottle B, a centrifugal tube and a color gradation card, the reagent bottle A is filled with a p-aminobenzene sulfonic acid solution, and the reagent bottle B is filled with an N-(1-naphthyl) ethylenediamine hydrochloride aqueous solution. Taking supernate as sample liquid to be detected; according to the kit, nitrite and p-aminobenzene sulfonic acid are subjected to a diazo reaction and coupled with N-(1-naphthyl) ethylenediamine hydrochloride to form a purplish-red azo compound, the detection sensitivity and accuracy are remarkably improved, the kit is suitable for various food matrixes, and the detection sensitivity and accuracy are improved. Multiple defects existing in a traditional detection method are successfully overcome, an efficient solution is provided for rapid screening of illegal addition of nitrite, and the method has wide market application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of detection kits, and in particular to a nitrite rapid screening kit and a method for using the same. Background Art

[0002] Nitrite (NO2 - ) is a food additive widely used in meat processing. It can inhibit the growth of Clostridium botulinum and thus maintain the surface gloss of meat products. However, excessive intake of nitrite can lead to methemoglobinemia and react with secondary amines to form strong carcinogen nitrosamine compounds, which seriously endanger human life and health. my country's "National Food Safety Standard" sets strict limits for it (such as cured meat products ≤30mg / kg), but some unscrupulous businesses still add nitrite in violation of regulations. Therefore, the development of efficient and accurate nitrite detection technology is of great significance to ensuring food safety.

[0003] At present, the main methods for nitrite detection are spectrophotometry, ion chromatography, liquid chromatography-mass spectrometry, etc. Although the above methods are highly accurate, they have problems such as high equipment cost, complex operation, and poor timeliness. They are difficult to adapt to the needs of grassroots market supervision, self-inspection of food companies, and on-site rapid testing by consumers. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the purpose of the present invention is to provide a nitrite rapid screening kit and a method for using the same, which has the characteristics of high sensitivity, strong anti-interference ability and simple operation.

[0006] To achieve the above-mentioned purpose, the present invention proposes a nitrite rapid screening kit, which contains a reagent bottle A, a reagent bottle B, a centrifuge tube and a color scale card, wherein the reagent bottle A contains a p-aminobenzenesulfonic acid solution, and the reagent bottle B contains a naphthylethylenediamine hydrochloride aqueous solution.

[0007] Furthermore, the p-aminobenzenesulfonic acid solution is 0.15-0.3 g of p-aminobenzenesulfonic acid dissolved in 100 ml of hydrochloric acid buffer with a pH value of 4-5; the naphthylethylenediamine hydrochloride aqueous solution is 0.15-0.3 g of naphthylethylenediamine hydrochloride dissolved in 100 ml of aqueous solution.

[0008] Furthermore, the capacity of the centrifuge tube is 1.5 to 2 ml, and the number of the reagent bottle A, reagent bottle B, centrifuge tube and color scale card is 50 to 100.

[0009] Another object of the present invention is to provide a method for using a nitrite rapid screening kit, wherein the method comprises the following steps:

[0010] S1. Sample preparation: Weigh and chop the sample, add 5 to 15 times the sample volume of purified water, shake thoroughly, let it stand for 5 to 10 minutes, take the supernatant as the sample solution, and dilute it;

[0011] S2. Sample test: Take a centrifuge tube and add 1 to 3 drops of reagent A in the reagent bottle, add 1 ml of the sample solution to be tested; add 1 to 3 drops of reagent B in the reagent bottle, shake well, and let it stand for 5 to 10 minutes;

[0012] S3. Interpretation of results: Observe the color change of the liquid in the centrifuge tube, compare the color with the color scale card, and obtain the reading. Multiply the reading by the dilution factor to obtain the nitrite content in the sample to be tested. The dilution factor is the ratio of the original concentration of the sample to be tested to the concentration after dilution.

[0013] Furthermore, after S1 is allowed to stand, it is filtered or centrifuged. If the color after color development in S3 is very dark and a precipitate is produced, or if color develops immediately upon addition of reagent B but quickly fades to light yellow, indicating that the nitrite content in the sample is very high, the sample solution in S1 should be diluted more and retested.

[0014] Beneficial effects: The present invention diazotizes nitrite with aminobenzenesulfonic acid under weakly acidic conditions to generate a diazonium salt, which is then coupled with naphthylethylenediamine hydrochloride to form a purple-red azo compound, wherein the color depth is proportional to the nitrite concentration. Finally, semi-quantitative analysis is achieved through color scale card comparison. The present invention can effectively improve sensitivity, enhance anti-interference ability, and greatly improve operational convenience and wide application.

[0015] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0017] Figure 1 Schematic diagram of the structure of a nitrite rapid screening kit according to one embodiment of the present invention.

[0018] As shown in the figure: 1. Reagent kit; 2. Reagent bottle A; 3. Reagent bottle B; 4. Centrifuge tube; 5. Color scale card. DETAILED DESCRIPTION

[0019] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0020] The following describes the nitrite rapid screening kit and its use method according to the embodiment of the present invention in conjunction with the accompanying drawings.

[0021] Example 1

[0022] (1) Purchase beef, mince it, and weigh 2g of sample. Add 10ml of purified water, shake thoroughly, let it stand for 5 minutes, and collect the supernatant as the sample solution.

[0023] (2) Take a 1.5ml centrifuge tube, add 1 drop of reagent A from the reagent bottle, 1ml of the sample solution, and 1 drop of reagent B from the reagent bottle, shake well and let it stand for 5 minutes.

[0024] (3) Observe the color change of the liquid in the tube and compare the color with a color scale card. If the color is normal and there is no abnormality, multiply the reading by the dilution factor to obtain the nitrite content in the sample to be tested.

[0025] The following table shows the experimental data related to the treatment process of Example 1:

[0026] Sample Information

[0027] Sample name: beef

[0028] Sample status: Refrigerator fresh

[0029] Sampling part: Inside of beef

[0030] Pre-processing data

[0031]

[0032] Reaction system data

[0033]

[0034] Result interpretation data

[0035]

[0036] Example 2

[0037] (1) Purchase sausage, chop it into small pieces, and weigh 2 g of sample. Add 10 ml of purified water, shake thoroughly, and let it stand for 5 minutes. The supernatant is used as the sample solution.

[0038] (2) Take a 1.5ml centrifuge tube, add 1 drop of reagent A from the reagent bottle, 1ml of the sample solution, and 1 drop of reagent B from the reagent bottle, shake well and let it stand for 5 minutes.

[0039] (3) Observe the color change of the liquid in the tube and compare the color with a color scale card. If the color is normal and there is no abnormality, multiply the reading by the dilution factor to obtain the nitrite content in the sample to be tested.

[0040] The following table shows the experimental data related to the treatment process of Example 2:

[0041] Sample Information

[0042] Sample name: Sausage

[0043] Sample status: Refrigerator fresh

[0044] Sampling site: Inside the sausage

[0045] Pre-processing data

[0046]

[0047] Reaction system data

[0048]

[0049] Result interpretation data

[0050]

[0051] It should be noted that:

[0052] 1. If the color after development is very dark and there is precipitation; or if color develops immediately when reagent B is added but quickly fades to light yellow, it means that the nitrite content in the sample is very high and the dilution factor needs to be increased and retested, otherwise the result will be inaccurate.

[0053] 2. If there is a high content of sodium bisulfite, ascorbic acid or soy sauce in the sample to be tested, it will have a certain impact on the color development results of this method, and attention should be paid during testing.

[0054] In summary, the nitrite rapid screening kit and its use method of the embodiments of the present invention are characterized by diazotizing nitrite with aminobenzenesulfonic acid under weakly acidic conditions to form a diazonium salt, which is then coupled with naphthylethylenediamine hydrochloride to form a purple-red azo compound, the color depth of which is proportional to the nitrite concentration. Finally, semi-quantitative analysis is achieved through color scale card comparison. The present invention can effectively improve sensitivity, enhance anti-interference ability, and greatly improve operational convenience and wide application.

[0055] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and deform the above embodiments within the scope of the present invention.

Claims

1. A nitrite rapid screening kit, characterized in that: The reagent kit (1) is internally provided with a reagent bottle A (2), a reagent bottle B (3), a centrifuge tube (4) and a color scale card (5), wherein the reagent bottle A (2) is provided with a p-aminobenzenesulfonic acid solution, and the reagent bottle B (3) is provided with a naphthylethylenediamine hydrochloride aqueous solution.

2. The nitrite rapid screening kit according to claim 1, wherein The sulfanilic acid solution is 0.15-0.3 g of sulfanilic acid dissolved in 100 ml of hydrochloric acid buffer with a pH value of 4-5; The aqueous solution of naphthylethylenediamine hydrochloride is 0.15-0.3g of naphthylethylenediamine hydrochloride dissolved in 100ml of aqueous solution.

3. The nitrite rapid screening kit according to claim 1, wherein The capacity of the centrifuge tube is 1.5 to 2 ml, and the number of the reagent bottle A (2), the reagent bottle B (3), the centrifuge tube (4) and the color scale card (5) is 50 to 100.

4. A method for using a nitrite rapid screening kit, using the nitrite rapid screening kit according to any one of claims 1 to 3, characterized in that: The method includes the following steps: S1. Sample preparation: Weigh and chop the sample, add 5 to 15 times the sample volume of purified water, shake thoroughly, let it stand for 5 to 10 minutes, take the supernatant as the sample solution, and dilute it; S2. Sample test: Take a centrifuge tube and add 1 to 3 drops of reagent A in the reagent bottle, add 1 ml of the sample solution to be tested; add 1 to 3 drops of reagent B in the reagent bottle, shake well, and let it stand for 5 to 10 minutes; S3. Interpretation of results: Observe the color change of the liquid in the centrifuge tube, compare the color with the color scale card, and obtain the reading. Multiply the reading by the dilution factor to obtain the nitrite content in the sample to be tested. The dilution factor is the ratio of the original concentration of the sample to be tested to the concentration after dilution.

5. The method for using the nitrite rapid screening kit according to claim 4, wherein: After standing in S1, filtering or centrifugation is performed; If the color of S3 is very dark and precipitate is produced; or if color develops immediately when reagent B is added but quickly fades to light yellow, it means that the nitrite content in the sample is very high. In this case, the sample solution in S1 should be diluted more and retested.

Images