Carbon dioxide concentration detection method based on carbon dioxide indicator

Abstract

The invention discloses a carbon dioxide concentration detection method based on a carbon dioxide indicator, and relates to the technical field of gas detection. The carbon dioxide indicator comprises a first part and a second part which are packaged in the breathable cavity and are mutually independent, and the first part comprises a fluorescent indicator; the second portion includes a color indicator. The detection method comprises the following steps: placing the carbon dioxide indicator in an environment to be detected, and measuring the fluorescence spectrum of the first part after the pH value of the second part is stable; according to the fluorescence spectrum and a preset carbon dioxide concentration-fluorescence intensity standard curve, the concentration of carbon dioxide in the environment to be detected is calculated, and the accurate quantitative effect is achieved. The method is simple and easy to operate, the carbon dioxide concentration in the environment to be detected can be quantitatively detected, the detection result of the carbon dioxide concentration is efficient and accurate, and the method has good application value.

Description

Technical Field

[0001] The present application relates to the technical field of gas detection, and in particular to a method for detecting carbon dioxide concentration based on a carbon dioxide indicator. Background Art

[0002] In the pharmaceutical and food fields, accurate monitoring and control of carbon dioxide concentration is crucial. Carbon dioxide is widely used in these fields in processes such as sterilization, preservation, fermentation and packaging, and changes in its concentration directly affect product quality, safety and shelf life. For example, in the pharmaceutical field, carbon dioxide is used for cell culture, anesthetic gas monitoring and drug packaging; in the food field, carbon dioxide is a key ingredient in modified atmosphere packaging and carbonated beverage production.

[0003] As a detection method based on chemical reactions, carbon dioxide indicators are gradually being used in the fields of medicine and food due to their advantages such as low cost, fast response, and easy operation. Carbon dioxide indicators are usually composed of pH-sensitive dyes and auxiliary components. Their working principle is based on the fact that carbon dioxide dissolves in water to form carbonic acid, which causes the pH value of the solution to change, thereby causing the color of the dye to change. The concentration of carbon dioxide can be detected by observing the color change or using spectral analysis technology.

[0004] However, the existing carbon dioxide indicator technology still has problems in the application of medicine and food fields, such as being mostly used for qualitative detection and difficulty in achieving high-precision quantitative detection.

[0005] A Chinese patent application with publication number CN 107179314 A discloses a composition for detecting carbon dioxide gas, a carbon dioxide gas indicator using the composition, and its application. The indicator is composed of a pH indicator, a solvent, and a self-adhesive sticker, and is used for a gas replacement package containing carbon dioxide gas. When the concentration of carbon dioxide gas in the package changes, the indicator may change color accordingly, which is used to verify and detect whether there are pores or poor sealing in the gas replacement package containing carbon dioxide. The indicator has a simple formula, does not contain any toxic or harmful solvents, and its color change reaction is sensitive and reliable. However, the application of the carbon dioxide gas indicator in the above patent application is still to use the carbon dioxide gas indicator to perform qualitative detection of carbon dioxide, rather than quantitative detection. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present application provides a method for detecting carbon dioxide concentration based on a carbon dioxide indicator. The detection method is based on a carbon dioxide indicator having a structure divided into two independent parts, and can quantitatively detect the carbon dioxide concentration in the environment where the indicator is located.

[0007] In order to achieve the above objectives, this application adopts the following technical solutions: The carbon dioxide indicator comprises a first part and a second part which are independent of each other and are encapsulated in a breathable cavity, wherein the first part comprises a fluorescent indicator; and the second part comprises a color indicator; and the carbon dioxide concentration detection method comprises: placing the carbon dioxide indicator in a test environment, and measuring the fluorescence spectrum of the first part after the pH value of the second part is stabilized; The concentration of carbon dioxide in the test environment is calculated based on the fluorescence spectrum and a preset carbon dioxide concentration-fluorescence intensity standard curve.

[0008] Beneficial technical effects: In the carbon dioxide concentration detection method provided by the present application, a simple but uniquely structured carbon dioxide indicator is used. The carbon dioxide indicator is divided into an independent first part and a second part, wherein the first part contains fluorescein isothiocyanate compounded with chitosan as a fluorescent indicator, which is used to reflect the change in fluorescence intensity of the carbon dioxide indicator under different environments with or without carbon dioxide. This change can be detected by an instrument and a carbon dioxide concentration-fluorescence intensity standard curve can be established to quantitatively detect carbon dioxide concentration. At the same time, since fluorescein isothiocyanate has been compounded with chitosan, the problem of pollution caused by the reaction of its isothiocyanate group with other substances is avoided. The second part contains a color indicator, which reflects the approximate situation of the carbon dioxide concentration in the environment where the carbon dioxide indicator is located through color changes, and the naked eye can easily detect this change. As a reminder or guidance, when the color of the second part is stable and the pH value test result of the second part is also stable, the fluorescence intensity of the first part that is not easily perceived by the naked eye can be detected again, and the test result is matched with the established carbon dioxide concentration-fluorescence intensity standard curve, and the specific value of the carbon dioxide concentration in the environment to be tested can be calculated to achieve a quantitative effect.

[0009] In addition, the structure in which the first part and the second part are independent of each other but combined together avoids the following situations that may occur after the two parts are mixed together: the change in color of the color indicator affects the change in fluorescence intensity of the fluorescent indicator and the test, and the fluorescent indicator may also change color and affect the color of the color indicator. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Schematic diagram of the structure of the carbon dioxide indicator.

[0011] Figure 2 It is a flow chart of a method for detecting carbon dioxide concentration based on a carbon dioxide indicator.

[0012] The meanings of the accompanying symbols: 1. first part; 2. second part; 3. heat-sealed structure; 4. breathable cavity; 5. fluorescent indicator; 6. color indicator. DETAILED DESCRIPTION

[0013] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the embodiments. However, this should not be understood as the scope of the present application being limited to the following examples. Without departing from the above-mentioned method ideas of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0014] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the application.

[0015] As used in this application, the singular forms "for", "or", "an", "any" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0016] The present application provides a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, wherein the structure of the carbon dioxide indicator is as follows: Figure 1 As shown, it includes a first part 1 and a second part 2 which are independent of each other and are enclosed in a breathable cavity 4, wherein the first part 1 includes a fluorescent indicator 5; and the second part 2 includes a color indicator 6. The first part 1 and the second part 2 are blocked by a heat-sealed structure 3; and the breathable cavity 4 includes a breathable visible packaging bag.

[0017] Among them, the fluorescence intensity of the fluorescent indicator 5 will change with the change of the carbon dioxide concentration in the environment, but the change needs to be characterized by corresponding fluorescence intensity detection. The color indicator 6 will change color with the change of the carbon dioxide concentration in the environment, and the change is easily noticeable by the naked eye. However, if the two are directly mixed and used, the color change of the color indicator 6 will affect the fluorescence intensity change and test of the fluorescent indicator 5, and the fluorescent indicator 5 may also change color and affect the color of the color indicator 6; therefore, the two need to be combined independently of each other, so that the color change of the color indicator 6 can prompt or guide the test of the fluorescence intensity change of the fluorescent indicator 5.

[0018] Figure 1 In the structural diagram of the heat-sealed structure 3, the air-permeable cavity 4, the fluorescent indicator 5 and the color indicator 6, the shapes are only for the convenience of describing the present application, and do not indicate or imply that the structure must have a specific shape; in addition, Figure 1 The orientation or positional relationship of the fluorescent indicator 5 in the first part 1 and the color indicator 6 in the second part 2 is also for the convenience of describing the present application, rather than indicating or implying that the structure referred to must have a specific orientation or positional relationship, and therefore cannot be understood as a limitation on the present application.

[0019] The carbon dioxide concentration detection method is as follows Figure 2 As shown, including: placing the carbon dioxide indicator in a test environment, and measuring the fluorescence spectrum of the first part 1 after the pH value of the second part 2 is stabilized; The concentration of carbon dioxide in the test environment is calculated based on the fluorescence spectrum and a preset carbon dioxide concentration-fluorescence intensity standard curve.

[0020] In a possible implementation, the carbon dioxide concentration-fluorescence intensity standard curve is obtained by deducting the fluorescence curve when the first part 1 does not absorb carbon dioxide from the fluorescence curve when the pH value is stable after the first part 1 absorbs carbon dioxide of a predetermined concentration.

[0021] In a possible implementation, the criterion for determining whether the pH value is stable is: the pH value is tested at least three times in a row, and the error between each result is no greater than 2%.

[0022] In a possible implementation, the predetermined concentration is 0 to 50000 ppm.

[0023] In a possible implementation, in the carbon dioxide indicator, the first part 1 and the second part 2 also include an alkaline agent, a surfactant, an antibacterial agent, an anti-ultraviolet agent and a diluent.

[0024] In a possible implementation, in the carbon dioxide indicator, the fluorescent indicator 5 of the first part 1 is modified fluorescein isothiocyanate; the modified fluorescein isothiocyanate compounded with chitosan, and its structure includes: , Where n is an integer in the range of 20 to 200.

[0025] In a possible implementation, in the carbon dioxide indicator, the color indicator 6 of the second part 2 includes any one of bromothymol blue, phenol red and cresol red.

[0026] In a possible implementation, in the carbon dioxide indicator, the alkaline reagent includes any one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate.

[0027] In a possible implementation, in the carbon dioxide indicator, the surfactant includes any one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and hexadecyltrimethylammonium bromide.

[0028] In a possible implementation, in the carbon dioxide indicator, the antibacterial agent includes any one or more of sodium benzoate, methylparaben and ethylparaben.

[0029] In a possible implementation, in the carbon dioxide indicator, the anti-ultraviolet agent includes any one or more of zinc oxide, titanium dioxide and phenyl salicylate.

[0030] In a possible implementation, in the carbon dioxide indicator, the diluent includes any one or both of ethanol and water.

[0031] In a possible implementation, in the carbon dioxide indicator, the mass ratio of the fluorescent indicator 5, the alkaline reagent, the surfactant, the antibacterial agent, the anti-ultraviolet agent and the diluent in the first part 1 is: (2~8): (0.5~10): (0.1~5): (0.5~2): (1~5): (80~90).

[0032] In a possible implementation, in the carbon dioxide indicator, the mass ratio of the color indicator 6, alkaline reagent, surfactant, antibacterial agent, anti-ultraviolet agent and diluent in the second part 2 is: (1-10): (0.1-10): (0.5-5): (0.5-5): (1-5): (80-90).

[0033] The experimental raw materials used in this application come from the following sources: Fluorescent indicator 5: Beijing Solebow Technology Co., Ltd.; Color indicator 6: Bashifu (Shanghai) Biopharmaceutical Technology Co., Ltd.; Alkaline reagent: Jiangsu Runfeng Synthetic Technology Co., Ltd.; Surfactant: Beijing Solebow Technology Co., Ltd.; Antimicrobial agent: Qianyan Chemical Technology (Wuhan) Co., Ltd. Anti-ultraviolet agent: Qianyan Chemical Technology (Wuhan) Co., Ltd.; Diluent: Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0034] The following will specifically describe a carbon dioxide concentration detection method based on a carbon dioxide indicator provided by the present application in combination with different examples.

[0035] Example 1: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and bromothymol blue like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 1000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, sodium hydroxide, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol; The mass ratio of modified fluorescein isothiocyanate, sodium hydroxide, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol is: 5:3:1:1:2:88; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of bromothymol blue, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water; The mass ratio of bromothymol blue, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water is: 6:4:1.5:1.5:2:85; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0036] Example 2: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and phenol red like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 5000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, potassium hydroxide, hexadecyltrimethylammonium bromide, ethylparaben, phenyl salicylate and water; The mass ratio of modified fluorescein isothiocyanate, potassium hydroxide, cetyltrimethylammonium bromide, ethylparaben, phenyl salicylate and water is: 4:5:2:1.5:3:84.5; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of phenol red, sodium bicarbonate, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol; The mass ratio of phenol red, sodium bicarbonate, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol is: 3:4:1.5:1:2:88.5; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0037] Example 3: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and cresol red like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 10000 ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, sodium carbonate, sodium dodecylbenzene sulfonate, methyl paraben, titanium dioxide and water; The mass ratio of modified fluorescein isothiocyanate, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water is: 8:5:3:2:2:80; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of cresol red, sodium hydroxide, cetyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol; The mass ratio of cresol red, sodium hydroxide, cetyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol is: 4:2:1.5:0.5:2:90; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0038] Example 4: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and phenol red like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 20000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, potassium hydroxide, sodium dodecyl sulfate, ethyl paraben, zinc oxide and water; The mass ratio of modified fluorescein isothiocyanate, potassium hydroxide, sodium dodecyl sulfate, ethylparaben, zinc oxide and water is: 6:4:2:1.5:2.5:84; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of phenol red, sodium bicarbonate, sodium dodecylbenzene sulfonate, sodium benzoate, titanium dioxide and ethanol; The mass ratio of phenol red, sodium bicarbonate, sodium dodecylbenzene sulfonate, sodium benzoate, titanium dioxide and ethanol is: 6:3:1.5:1:2:86.5; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0039] Example 5: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and cresol red like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 40000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, sodium hydroxide, cetyltrimethylammonium bromide, methylparaben, phenyl salicylate and water; The mass ratio of modified fluorescein isothiocyanate, sodium hydroxide, cetyltrimethylammonium bromide, methylparaben, phenyl salicylate and water is: 7:3:2:1:5:82; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of cresol red, sodium carbonate, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol; The mass ratio of cresol red, sodium carbonate, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol is: 6:3:1.5:1.5:2:86; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0040] Example 6: Detection of carbon dioxide concentration based on modified fluorescein isothiocyanate and bromothymol blue like Figure 2 As shown, a method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 50000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, potassium hydroxide, sodium dodecylbenzene sulfonate, ethyl paraben, titanium dioxide and water; The mass ratio of modified fluorescein isothiocyanate, potassium hydroxide, sodium dodecylbenzene sulfonate, ethyl paraben, titanium dioxide and water is: 8:3:1:1:2.5:84.5; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of bromothymol blue, sodium bicarbonate, cetyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol; The mass ratio of bromothymol blue, sodium bicarbonate, cetyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol is: 5:2:2:1:3:87; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0041] Comparative Example 1: A method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. The first part 1 is composed of sodium hydroxide, sodium lauryl sulfate, sodium benzoate, zinc oxide and ethanol; The mass ratio of sodium hydroxide, sodium dodecyl sulfate, sodium benzoate, zinc oxide and ethanol is: 3:1:1:2:93; 2. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of bromothymol blue, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water; The mass ratio of bromothymol blue, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water is: 6:4:1.5:1.5:2:85.

[0042] In this comparative example, since the first part 1 does not contain the fluorescent indicator 5, it is impossible to establish a standard curve of carbon dioxide concentration-fluorescence intensity, so the carbon dioxide concentration can only be preliminarily determined by observing the color change of the second part 2, but cannot be quantified.

[0043] Comparative Example 2: A method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 10000 ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, sodium carbonate, sodium dodecylbenzene sulfonate, methyl paraben, titanium dioxide and water; The mass ratio of modified fluorescein isothiocyanate, sodium carbonate, sodium dodecylbenzene sulfonate, methylparaben, titanium dioxide and water is: 8:5:3:2:2:80; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment and detect its pH value at regular intervals to determine the carbon dioxide concentration; The second part 2 is composed of sodium hydroxide, hexadecyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol; The mass ratio of sodium hydroxide, hexadecyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol is: 2:1.5:0.5:2:94; 4. After the pH value of the second part 2 is stabilized, the fluorescence spectrum of the first part 1 of the carbon dioxide indicator is further detected, and the concentration of carbon dioxide in the test environment is calculated using the established carbon dioxide concentration-fluorescence intensity standard curve.

[0044] In this comparative example, since the second part 2 does not contain the color indicator 6, although a standard curve of carbon dioxide concentration-fluorescence intensity can be established, the carbon dioxide concentration cannot be preliminarily determined by observing the color change of the second part 2; therefore, the detection process lacks intuitiveness, and the carbon dioxide concentration can only be determined by continuously detecting the pH value of the second part 2, which is costly and inefficient.

[0045] Comparative Example 3: A method for detecting carbon dioxide concentration based on a carbon dioxide indicator, the detection method comprising: 1. First, detect and record the fluorescence curve of the first part 1 in a carbon dioxide-free environment, and place the first part 1 in a 50000ppm carbon dioxide atmosphere. After the pH value stabilizes, detect and record the fluorescence curve after absorbing carbon dioxide; The first part 1 is composed of modified fluorescein isothiocyanate, sodium dodecylbenzene sulfonate, ethyl paraben, titanium dioxide and water; The mass ratio of modified fluorescein isothiocyanate, sodium dodecylbenzene sulfonate, ethylparaben, titanium dioxide and water is: 8:1:1:2.5:87.5; 2. Use the fluorescence curve after carbon dioxide absorption to deduct the fluorescence curve when carbon dioxide is not absorbed to establish a standard curve of carbon dioxide concentration-fluorescence intensity; 3. Place the second part 2 in the test environment, observe its color change, and preliminarily determine the carbon dioxide concentration; The second part 2 is composed of bromothymol blue, hexadecyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol; The mass ratio of bromothymol blue, hexadecyltrimethylammonium bromide, sodium benzoate, phenyl salicylate and ethanol is: 5:2:1:3:89; 4. After the color of the second part 2 is stable and the pH value is also stable, further detect the fluorescence spectrum of the first part 1 of the carbon dioxide indicator, and use the established carbon dioxide concentration-fluorescence intensity standard curve to calculate the concentration of carbon dioxide in the test environment.

[0046] In this comparative example, since neither the first part 1 nor the second part 2 contains an alkaline reagent, although a standard curve of carbon dioxide concentration-fluorescence intensity can be established, the carbon dioxide concentration can also be preliminarily determined by observing the color change of the second part 2; however, the lack of an alkaline reagent makes it difficult to ensure the correspondence between the pH change and the fluorescence intensity change, which greatly reduces the sensitivity and accuracy of quantitative detection.

[0047] The above detection method is used to detect the carbon dioxide concentration of the environment to be tested, the color change of the second part 2 is observed and the fluorescence intensity change of the first part 1 is detected. The results are shown in Table 1.

[0048] Table 1 Examples 1 to 6 and Comparative Examples 1 to 3 in CO 2 Changes in the color of the second part 2 and the fluorescence intensity of the first part 1 under the atmosphere

[0049] As can be seen from Table 1, in Examples 1 to 6, the second part 2 is 2 The color change caused by the increase in absorption can guide the detection of the change in the fluorescence intensity of the first part 1, so as to further calculate the concentration of carbon dioxide in the environment through the established carbon dioxide concentration-fluorescence intensity standard curve.

[0050] In comparative example 1, the first part 1 does not contain the fluorescent indicator 5, so it is impossible to establish a standard curve of carbon dioxide concentration-fluorescence intensity; in comparative example 2, the second part 2 does not contain the color indicator 6, so the detection process lacks intuitiveness, and the carbon dioxide concentration can only be determined by continuously detecting the pH value of the second part 2, which is costly and inefficient; in comparative example 3, neither the first part 1 nor the second part 2 contains an alkaline reagent, and the sensitivity and accuracy of quantitative detection are greatly reduced.

[0051] The above results show and describe the basic principles and main features of the present application as well as the advantages of the present application.

[0052] Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection sought in the present application is defined by the equivalents of the attached claims.

Claims

1. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator, characterized in that: The carbon dioxide indicator comprises a first part (1) and a second part (2) which are independent of each other and are encapsulated in a gas-permeable cavity (4); the first part (1) comprises a fluorescent indicator (5); the second part (2) comprises a color indicator (6); the carbon dioxide concentration detection method comprises: Placing the carbon dioxide indicator in a test environment, and measuring the fluorescence spectrum of the first part (1) after the pH value of the second part (2) is stabilized; The concentration of carbon dioxide in the test environment is calculated based on the fluorescence spectrum and a preset carbon dioxide concentration-fluorescence intensity standard curve.

2. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 1, characterized in that: The carbon dioxide concentration-fluorescence intensity standard curve is obtained by deducting the fluorescence curve when the first part (1) does not absorb carbon dioxide from the fluorescence curve when the pH value is stable after the first part (1) absorbs a predetermined concentration of carbon dioxide.

3. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 1, characterized in that: In the carbon dioxide indicator, the first part (1) and the second part (2) are separated by a heat-sealed structure (3); the first part (1) and the second part (2) also include an alkaline agent, a surfactant, an antibacterial agent, an anti-ultraviolet agent and a diluent.

4. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 1, characterized in that: In the carbon dioxide indicator, the fluorescent indicator (5) of the first part (1) is modified fluorescein isothiocyanate; The modified fluorescein isothiocyanate is fluorescein isothiocyanate compounded with chitosan, and its structure includes: ， wherein n is an integer in the range of 20 to 200; and the color indicator (6) of the second part (2) comprises any one of bromothymol blue, phenol red and cresol red.

5. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 3, characterized in that: In the carbon dioxide indicator, the alkaline reagent includes any one or more of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate.

6. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 3, characterized in that: In the carbon dioxide indicator, the surfactant includes any one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and hexadecyltrimethylammonium bromide.

7. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 3, characterized in that: In the carbon dioxide indicator, the antibacterial agent includes any one or more of sodium benzoate, methylparaben and ethylparaben.

8. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 3, characterized in that: In the carbon dioxide indicator, the anti-ultraviolet agent includes any one or more of zinc oxide, titanium dioxide and phenyl salicylate.

9. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator as claimed in claim 3, characterized in that: In the carbon dioxide indicator, the diluent includes any one or both of ethanol and water.

10. A method for detecting carbon dioxide concentration based on a carbon dioxide indicator according to any one of claims 1 to 9, characterized in that: In the carbon dioxide indicator, the mass ratio of the fluorescent indicator (5), alkaline agent, surfactant, antibacterial agent, anti-ultraviolet agent and diluent in the first part (1) is: (2-8): (0.5-10): (0.1-5): (0.5-2): (1-5): (80-90); the mass ratio of the color indicator (6), alkaline agent, surfactant, antibacterial agent, anti-ultraviolet agent and diluent in the second part (2) is: (1-10): (0.1-10): (0.5-5): (0.5-5): (1-5): (80-90).

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