An oxidatively color-changing time indicator strip and a method for preparing the same

Abstract

The application discloses an oxidation discoloration time indicating strip and a preparation method thereof, and belongs to the technical field of indicating strips.The method comprises the following steps: preparing a buffer solution with a pH value of 11-12, a glucose aqueous solution and an alkaline methylene blue aqueous solution; mixing the three solutions to obtain an alkaline methylene blue-glucose solution; after the blue color of the solution disappears, mixing the solution with sodium ascorbate solid and a humectant to obtain an alkaline methylene blue-glucose-sodium ascorbate solution; and immersing a carrier in the solution, and packaging the carrier to obtain the indicating strip. The pH value of the solution is stabilized at 11-12, and the reducing property of sodium ascorbate is enhanced; the preparation method is simple, and the cost is low; the obtained indicating strip can change from colorless to blue after contacting oxygen, the discoloration time is stable, the indicating effect is obvious, and the indicating strip is suitable for time prompting after a sealed product is opened.

Description

Technical Field

[0001] This invention relates to the field of indicator strip technology, and in particular to an oxidation color change time indicator strip and its preparation method. Background Technology

[0002] Currently, most sealed products on the market use mechanical or electronic methods to indicate the time after opening. These methods are used for mass-produced, inexpensive everyday items such as bottled water, but are characterized by high cost, complex manufacturing, and susceptibility to damage. Similar indicator strips for oxygen are available, but they change color quickly or produce dull colors with inconspicuous changes, and are not used for indicating the time after opening in sealed products. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the problems of high cost, complex manufacturing and easy damage of the indication method in the prior art; and the problem of fast color change or dull color and unclear change of the indicator. The present invention provides an oxidation color change time indicator strip and its preparation method.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing an oxidation color change time indicator strip, comprising the following steps:

[0006] (1) Prepare a buffer solution with a pH of 11-12; prepare a glucose aqueous solution; prepare an alkaline methylene blue aqueous solution;

[0007] (2) The buffer solution, the basic methylene blue aqueous solution, and the glucose aqueous solution are mixed to obtain an basic methylene blue-glucose solution, wherein the pH value of the basic methylene blue-glucose solution is 11-12;

[0008] (3) After the blue color of the alkaline methylene blue-glucose solution fades, the alkaline methylene blue-glucose solution, sodium ascorbate solid, and humectant are mixed to obtain an alkaline methylene blue-glucose-sodium ascorbate solution.

[0009] (4) The carrier is immersed in the methylene blue-glucose-sodium ascorbate solution and then packaged to obtain an oxidation color change time indicator strip.

[0010] Preferably, the buffer solution is a mixed aqueous solution of tartaric acid, sodium chloride and sodium hydroxide, wherein the concentration of tartaric acid in the buffer solution is 0.03-0.05 mol / L and the concentration of sodium chloride is 0.03-0.05 mol / L.

[0011] Preferably, the glucose aqueous solution has a glucose concentration of 16% by mass.

[0012] Preferably, the mass concentration of methylene blue in the alkaline methylene blue aqueous solution is 0.1%.

[0013] Preferably, the methylene blue-glucose-sodium ascorbate solution has a mass concentration of 0.03-0.04%, a glucose mass concentration of 2.91%, and a sodium ascorbate mass concentration of 4.25%.

[0014] Preferably, the carrier is qualitative filter paper and the humectant is glycerin.

[0015] Preferably, the packaging material is an LDPE plastic film bag, and the LDPE plastic film bag has 6 sets of small holes with a diameter of 1mm-1.5mm on both the front and back surfaces.

[0016] The present invention also provides an oxidation color change time indicator strip, which is prepared by the preparation method described in the above technical solution.

[0017] The positive and progressive effects of this invention are as follows: the pH value of the alkaline methylene blue-glucose-sodium ascorbate solution is stabilized at 11-12, which increases the reducing power of sodium ascorbate. The preparation method is simple and low in cost. The resulting oxidation color change time indicator strip has high indication robustness. By changing from colorless to blue within a specified time after being exposed to oxygen, it can indicate the opening and sealing time of the product. Attached Figure Description

[0018] Figure 1 This is a top view of the structure of the present invention. Detailed Implementation

[0019] This invention provides an oxidation color change time indicator strip and its preparation method, comprising the following steps:

[0020] (1) Prepare a buffer solution with a pH value of 11-12;

[0021] Prepare an aqueous solution of sodium ascorbate;

[0022] Prepare a glucose solution;

[0023] Prepare an alkaline methylene blue aqueous solution;

[0024] (2) The buffer solution, the basic methylene blue aqueous solution, and the glucose aqueous solution are mixed to obtain an basic methylene blue-glucose solution, wherein the pH value of the basic methylene blue-glucose solution is 11-12;

[0025] (3) After the blue color of the alkaline methylene blue-glucose solution fades, the alkaline methylene blue-glucose solution and sodium ascorbate solid are mixed to obtain an alkaline methylene blue-glucose-sodium ascorbate solution.

[0026] In this invention, the buffer solution has a pH of 11-12 and is a mixed aqueous solution of tartaric acid, sodium chloride, and sodium hydroxide. The concentration of tartaric acid in the buffer solution is preferably 0.03-0.05 mol / L, and the concentration of sodium chloride is preferably 0.03-0.05 mol / L.

[0027] The present invention does not specifically limit the preparation method of the buffer solution, as long as a buffer solution with the required pH value can be obtained. The preparation of the buffer solution preferably includes the following steps: mixing tartaric acid-sodium chloride aqueous solution and sodium hydroxide aqueous solution to obtain a buffer solution; the concentration of tartaric acid and sodium chloride in the tartaric acid-sodium chloride aqueous solution is preferably 0.1 mol / L, and the concentration of sodium hydroxide aqueous solution is preferably 0.1 mol / L.

[0028] In this invention, the glucose concentration in the glucose aqueous solution is preferably 16%.

[0029] In this invention, the preferred mass concentration of methylene blue in the alkaline methylene blue aqueous solution is 0.1%, and the preferred pH value is 11-12. The pH of the alkaline methylene blue aqueous solution is preferably adjusted using a sodium hydroxide aqueous solution. There are no particular limitations on the preparation method; any method that yields an alkaline methylene blue solution with the desired pH value is acceptable.

[0030] In this invention, the mass concentration of methylene blue in the alkaline methylene blue-glucose-sodium ascorbate solution is preferably 0.03-0.04%, and most preferably 0.037%; the mass concentration of glucose is preferably 2.91%, and the mass concentration of sodium ascorbate is preferably 4.25%.

[0031] In this invention, the carrier is preferably qualitative filter paper, and the humectant is preferably glycerin. The packaging material is preferably an LDPE plastic film bag, and the LDPE plastic film bag has 6 sets of small holes with a diameter of 1mm-1.5mm on both the front and back surfaces.

[0032] (4) After the carrier is immersed in the methylene blue-glucose-sodium ascorbate solution, it is packaged to obtain an oxidation color change time indicator strip.

[0033] In this invention, the immersion time is preferably 60–120 seconds; the immersion temperature is not particularly limited, but in this embodiment, the immersion is preferably carried out at room temperature. After immersion, the carrier impregnated with the alkaline methylene blue-glucose-sodium ascorbate solution is preferably removed, and then the LDPE porous plastic film is heat-pressed and packaged using a compression molding machine.

[0034] The following detailed description, in conjunction with embodiments, illustrates an oxidation color change time indicator strip and its preparation method provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0035] (1) A tartaric acid-sodium chloride aqueous solution with a concentration of 0.1 mol / L and a sodium hydroxide aqueous solution with a concentration of 0.1 mol / L are mixed in a volume ratio of 2:1 to obtain a buffer solution with a pH value of 11-12.

[0036] (2) Prepare a 10% sodium ascorbate aqueous solution;

[0037] (3) Prepare a 16% glucose aqueous solution;

[0038] (4) Add 0.2g of sodium hydroxide solid to 100ml of methylene blue solution with a mass concentration of 0.1% to obtain an alkaline methylene blue solution;

[0039] (5) Mix 20ml of buffer solution, 9.5ml of glucose solution and 20.5ml of basic methylene blue solution to obtain 50ml of basic methylene blue-glucose solution with a pH of 11-12;

[0040] (6) After the color of the above alkaline methylene blue-glucose solution fades, add 2.12g of sodium ascorbate solid and 1ml of glycerol to obtain alkaline methylene blue-glucose-sodium ascorbate solution.

[0041] (7) Soak the qualitative filter paper strip in alkaline methylene blue-glucose-sodium ascorbate solution for 1 minute. After taking it out, complete the hot-press packaging of LDPE porous plastic film under the compression molding machine to obtain the oxidation color change time indicator strip.

[0042] Test response time: The oxidation color change time indicator strip in the example was placed in an air atmosphere (oxygen content 21%), and the color change time was recorded. A total of 5 groups were tested, and the indicator strip changed from colorless to blue, with the color change time ranging from 2.2h to 2.67h.

[0043] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for producing an oxidation discoloration time indicating strip, characterized by, It consists of the following steps: (1) Prepare a buffer solution with a pH of 11-12; the buffer solution is a mixed aqueous solution of tartaric acid, sodium chloride and sodium hydroxide; prepare a glucose aqueous solution; prepare an alkaline methylene blue aqueous solution; (2) The buffer solution, the basic methylene blue aqueous solution, and the glucose aqueous solution are mixed to obtain an basic methylene blue-glucose solution, wherein the pH value of the basic methylene blue-glucose solution is 11-12; (3) After the blue color of the alkaline methylene blue-glucose solution fades, the alkaline methylene blue-glucose solution, sodium ascorbate solid, and humectant are mixed to obtain an alkaline methylene blue-glucose-sodium ascorbate solution. (4) The carrier is immersed in the methylene blue-glucose-sodium ascorbate solution and then packaged to obtain an oxidation color change time indicator strip.

2. The production method according to claim 1, characterized by, The buffer solution is a mixed aqueous solution of tartaric acid, sodium chloride and sodium hydroxide, wherein the concentration of tartaric acid in the buffer solution is 0.03-0.05 mol / L and the concentration of sodium chloride is 0.03-0.05 mol / L.

3. The preparation method according to claim 1, characterized in that, The glucose aqueous solution has a glucose concentration of 16% by mass.

4. The preparation method according to claim 1, characterized in that, The mass concentration of methylene blue in the alkaline methylene blue aqueous solution is 0.1%.

5. The preparation method according to claim 1, characterized in that, The basic methylene blue-glucose-sodium ascorbate solution contains 0.03-0.04% methylene blue, 2.91% glucose, and 4.25% sodium ascorbate.

6. The preparation method according to claim 1, characterized in that, The carrier is qualitative filter paper, and the humectant is glycerin.

7. The preparation method according to claim 1, characterized in that, The packaging material is an LDPE plastic film bag, and the LDPE plastic film bag has 6 sets of small holes with a diameter of 1mm-1.5mm on both the front and back surfaces.

8. An oxidation color change time indicator strip, prepared by the preparation method according to any one of claims 1 to 7.

Images