A storage method and storage structure of ascorbic acid solution for microfluidic total phosphorus testing

Abstract

The present invention proposes a preservation method and preservation structure for an ascorbic acid solution for microfluidic total phosphorus test, the preservation method including adding dimercaptopropane sulfonic acid to the ascorbic acid solution, and then sealing the resulting mixed solution in a dark place for preservation. The preservation structure includes a shell and a sealing film, the shell including a hollow inner cavity and an opening, the opening communicating the hollow inner cavity and the outside of the shell, the sealing film being sealed and installed at the opening, and the inside of the hollow inner cavity being filled with ascorbic acid solution and dimercaptopropane sulfonic acid. The preservation method for the ascorbic acid solution for microfluidic total phosphorus test of the present invention can effectively alleviate the deterioration of the ascorbic acid solution and extend the storage period of the device, thereby enabling it to be more suitable for the operation requirements of the water quality detection system of microfluidics.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental monitoring, and in particular to a storage method and storage structure of an ascorbic acid solution for microfluidic total phosphorus testing. Background Art

[0002] When microfluidic chip technology is applied to total phosphorus water quality testing, according to the national standards for spectrophotometric methods for total phosphorus testing in water, the color developer ammonium molybdate solution contains sulfuric acid, which is not easy to make into a freeze-dried reagent. Therefore, in actual applications, it still needs to be stored directly in liquid form. However, there are major limitations when storing total phosphorus reagents in liquid form, especially the reducing agent ascorbic acid solution, which is extremely unstable and easily affected by factors such as light, temperature, air, and trace copper ions, causing it to become ineffective. The shelf life of this solution is usually 2-4 weeks when stored in a cool, dark place.

[0003] In the prior art, Chinese patent CN109596521A uses an improved preparation method to add glacial acetic acid or EDTA to the solution, or to pass nitrogen, but the stability of the ascorbic acid solution is still no more than 4 months. Therefore, neither the direct preparation method of the ascorbic acid reducing agent nor the improved method can meet the microfluidic chip requirement for a storage period of more than 6 months for the total phosphorus preformed reagent.

[0004] The main reason for the deterioration of ascorbic acid solution is that ascorbic acid is relatively stable in a dry state, but in solution, the structure of the enediol group in its molecular structure will be quickly oxidized and further oxidized to form a yellow diketone compound. When encountering oxygen, heat, light, alkaline substances and trace metal ions such as copper in the air, it will further oxidize and break rapidly to form a series of colored oxidized substances. At the same time, the structure of the inner ring ester is extremely easy to hydrolyze. Temperature, pH, copper ions, etc. are all factors that affect the stability of ascorbic acid.

[0005] How to provide a safe and reliable method for preserving ascorbic acid solution for microfluidic total phosphorus testing without affecting the total phosphorus test results has become a technical problem that urgently needs to be solved in the field of microfluidic water quality testing technology. Summary of the Invention

[0006] In view of this, the present invention proposes a storage method and storage structure for an ascorbic acid solution for microfluidic total phosphorus testing, which can be used in the field of microfluidic water quality detection technology.

[0007] The technical solution of the present invention is achieved as follows: The present invention provides a method for preserving an ascorbic acid solution for microfluidic total phosphorus testing, comprising: adding dimercaptopropanesulfonic acid to the ascorbic acid solution, and then sealing and preserving the resulting mixed solution in a light-proof place.

[0008] Based on the above technical solution, preferably, the concentration of the ascorbic acid solution is 100 g / L, and the ascorbic acid solution is at least analytically pure.

[0009] Based on the above technical solution, preferably, the mass of dimercaptopropanesulfonic acid added to each milliliter of ascorbic acid solution is 0.01-2 mg.

[0010] On the basis of the above technical solution, preferably, the water used to prepare the ascorbic acid solution is ultrapure oxygen-free water, and the resistance value of the ultrapure oxygen-free water is ≥18 MΩ·cm.

[0011] More preferably, the obtained mixed solution is sealed and stored under an inert gas atmosphere.

[0012] The present invention also provides a storage structure for ascorbic acid solution for microfluidic total phosphorus testing, comprising a shell and a sealing film. The shell comprises a hollow inner cavity and an opening, the opening connecting the hollow inner cavity and the outside of the shell. The sealing film is sealed and installed at the opening, and the interior of the hollow inner cavity is filled with ascorbic acid solution and dimercaptopropane sulfonic acid.

[0013] Based on the above technical solution, preferably, the concentration of the ascorbic acid solution filled in the hollow inner cavity is 100 g / L, and the ascorbic acid solution is at least analytically pure.

[0014] Based on the above technical solution, preferably, the mass of dimercaptopropanesulfonic acid added to each milliliter of ascorbic acid solution is 0.01-2 mg.

[0015] On the basis of the above technical solution, preferably, the water used to prepare the ascorbic acid solution is ultrapure oxygen-free water, and the resistance value of the ultrapure oxygen-free water is ≥18 MΩ·cm.

[0016] On the basis of the above technical solutions, preferably, the shell can be made of a polymer material such as polypropylene, polyvinyl chloride, polystyrene, etc., and the sealing film can be made of a polymer composite material such as aluminum-plastic film, polyvinyl alcohol, etc.

[0017] The storage method and storage structure of the ascorbic acid solution for microfluidic total phosphorus testing of the present invention have the following beneficial effects compared with the prior art:

[0018] (1) The storage method of the present invention uses the addition of stabilizing dimercaptopropanesulfonic acid to the ascorbic acid solution. Dimercaptopropanesulfonic acid has a strong complexing effect on trace amounts of metal ions such as copper ions. When combined with the ascorbic acid solution prepared with oxygen-free ultrapure water and stored in a sealed and light-proof environment, the shelf life of the ascorbic acid solution can be greatly extended.

[0019] (2) The present invention also provides a storage structure. This storage structure can provide a structural basis for the storage of ascorbic acid solution used for microfluidic total phosphorus testing. At the same time, this structure can also be directly applied to microfluidic water quality testing equipment.

[0020] (3) The preservation method provided by the present invention has almost no effect on the total phosphorus test results, and can effectively extend the storage time of the ascorbic acid solution used for microfluidic total phosphorus testing to six months. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 A side cross-sectional view of a storage structure of an ascorbic acid solution for microfluidic total phosphorus testing according to the present invention;

[0023] Figure 2 This is a side cross-sectional view of the explosion state of the storage structure of the ascorbic acid solution for microfluidic total phosphorus testing of the present invention.

[0024] In the figure: 1-shell, 2-sealing film, 11-hollow inner cavity, 12-opening. DETAILED DESCRIPTION

[0025] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] like Figure 1 As shown, combined Figure 2 The present invention provides a storage structure for an ascorbic acid solution for microfluidic total phosphorus testing and a storage method for an ascorbic acid solution for microfluidic total phosphorus testing. Specifically, the method comprises: adding dimercaptopropanesulfonic acid to the ascorbic acid solution, and then sealing and storing the resulting mixed solution in a light-proof place at a storage temperature of 0-30°C.

[0027] In the above embodiment, the obtained ascorbic acid solution with good shelf life is a detection reagent for total phosphorus detection in water quality.

[0028] As a specific embodiment, the concentration of the ascorbic acid solution is 100 g / L, and the ascorbic acid solution is at least analytically pure.

[0029] As a specific embodiment, the mass of dimercaptopropanesulfonic acid added to each milliliter of ascorbic acid solution is 0.01-2 mg.

[0030] As a specific embodiment, the water used to prepare the ascorbic acid solution is ultrapure oxygen-free water, and the resistance value of the ultrapure oxygen-free water is ≥18 MΩ·cm.

[0031] As a specific embodiment, the obtained mixed solution is sealed and stored under an inert gas atmosphere.

[0032] The storage structure of the ascorbic acid solution for microfluidic total phosphorus testing of the present invention includes a shell 1 and a sealing film 2. The shell 1 includes a hollow inner cavity 11 and an opening 12. The opening 12 connects the hollow inner cavity 11 and the outside of the shell 1. The sealing film 2 is sealed and installed at the opening 12. The interior of the hollow inner cavity 11 is filled with ascorbic acid solution and dimercaptopropane sulfonic acid.

[0033] As a specific embodiment, the shell 1 can be made of organic polymer materials such as polypropylene, polyvinyl chloride, polystyrene, etc., and the sealing film 2 can be made of polymer composite materials such as aluminum-plastic film, polyvinyl alcohol, etc.

[0034] Example 1

[0035] 100 ml of an ascorbic acid solution with a concentration of 100 g / L was prepared with ultrapure oxygen-free water having a resistance value of ≥18 MΩ·cm, 1 mg of dimercaptopropanesulfonic acid was added thereto, and the mixture was prepared into a mixed solution under a nitrogen atmosphere.

[0036] The mixed solution obtained by the above preparation was added into 9 polypropylene shells under nitrogen atmosphere, sealed with aluminum plastic film, and stored at 10° C. in the dark.

[0037] Example 2

[0038] 100 ml of an ascorbic acid solution with a concentration of 100 g / L was prepared with ultrapure oxygen-free water having a resistance value of ≥18 MΩ·cm, 10 mg of dimercaptopropanesulfonic acid was added thereto, and the mixture was prepared into a mixed solution under a nitrogen atmosphere.

[0039] The mixed solution obtained by the above preparation was added into 9 polypropylene shells under nitrogen atmosphere, sealed with aluminum plastic film, and stored at 4° C. in the dark.

[0040] Example 3

[0041] 100 ml of an ascorbic acid solution with a concentration of 100 g / L was prepared with ultrapure oxygen-free water having a resistance value of ≥18 MΩ·cm, 100 mg of dimercaptopropanesulfonic acid was added thereto, and the mixture was prepared into a mixed solution under a nitrogen atmosphere.

[0042] The mixed solution obtained by the above preparation was added into 9 polypropylene shells respectively under nitrogen atmosphere, sealed with aluminum plastic film, and stored at 20° C. in the dark.

[0043] Example 4

[0044] 100 ml of an ascorbic acid solution with a concentration of 100 g / L was prepared with ultrapure oxygen-free water having a resistance value of ≥18 MΩ·cm, to which 200 mg of dimercaptopropanesulfonic acid was added, and the mixture was prepared into a mixed solution under a nitrogen atmosphere.

[0045] The mixed solution obtained by the above preparation was added into 9 polypropylene shells respectively under nitrogen atmosphere, sealed with aluminum plastic film, and stored at 30° C. in the dark.

[0046] Comparative Example 1

[0047] Prepare 100 ml of a 100 g / L ascorbic acid solution using ultrapure oxygen-free water with a resistance value ≥ 18 MΩ·cm. Add the ascorbic acid solution to nine polypropylene shells under a nitrogen atmosphere, seal the shells with aluminum-plastic film, and store at 4°C in the dark.

[0048] Comparative Example 2

[0049] 100 ml of a 100 g / L ascorbic acid solution was prepared with purified water having a resistance value of less than 10 MΩ·cm, 10 mg of dimercaptopropanesulfonic acid was added thereto, and the mixture was prepared into a mixed solution under a nitrogen atmosphere.

[0050] The mixed solution obtained by the above preparation was added into 9 polypropylene shells under nitrogen atmosphere, sealed with aluminum plastic film, and stored at 4° C. in the dark.

[0051] A freshly prepared 0.4 mg / L KH2PO4 standard solution was taken. Every month, a shell encapsulated with ascorbic acid solution was taken from each of Examples 1-4 and the comparative example, and the ascorbic acid solution therein was subjected to a color stability test. The results are shown in the following table:

[0052]

[0053]

[0054] It is not difficult to see that the preservation method adopted in the technical solution of the present application has a significant effect on prolonging the effectiveness of the ascorbic acid solution. Compared with the conventional ascorbic acid solution, the effectiveness of the ascorbic acid solution preserved under the preservation method of the present application is significantly retained and prolonged. At the same time, the absorbance value level of the conventional ascorbic acid solution can reach the level of the ascorbic acid preserved by the preservation method of the present application after six months.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preserving ascorbic acid solution for microfluidic total phosphorus testing, characterized in that: include: Dimercaptopropanesulfonic acid is added to an ascorbic acid solution, and the resulting mixed solution is then sealed and stored in a dark place; the mass of dimercaptopropanesulfonic acid added per milliliter of ascorbic acid solution is 0.01-2 mg; the water used to prepare the ascorbic acid solution is ultrapure oxygen-free water, and the resistance value of the ultrapure oxygen-free water is ≥18 MΩ·cm; and the resulting mixed solution is sealed and stored under an inert gas atmosphere.

2. The method for preserving the ascorbic acid solution for microfluidic total phosphorus testing according to claim 1, wherein: The concentration of the ascorbic acid solution is 100 g / L, and the ascorbic acid solution is at least analytically pure.

3. The method for preserving the ascorbic acid solution for microfluidic total phosphorus testing according to claim 1, wherein: The preservation method is achieved through a structure comprising a shell (1) and a sealing film (2), wherein the shell (1) comprises a hollow inner cavity (11) and an opening (12), wherein the opening (12) communicates with the hollow inner cavity (11) and the outer side of the shell (1), and the sealing film (2) is sealed and installed at the opening (12), and the interior of the hollow inner cavity (11) is filled with ascorbic acid solution and dimercaptopropanesulfonic acid.

4. The method for preserving the ascorbic acid solution for microfluidic total phosphorus testing according to claim 3, wherein: The shell (1) is made of an organic polymer material, and the sealing film (2) is made of a polymer composite material.

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