Method for detecting coloring agent in children cosmetics based on biomass carbon quantum dot compound

Abstract

The invention discloses a method for detecting a coloring agent in children cosmetics based on a biomass carbon quantum dot compound. The method comprises the following specific steps: (1) adding a surfactant into a mixed solution composed of ethanol and water to prepare an extraction solvent containing the surfactant; (2) adding the colorant-containing children cosmetic sample into an extraction solvent containing a surfactant, carrying out microwave heating extraction, and carrying out centrifugal separation to obtain a colorant-containing sample extracting solution; (3) adding inorganic salt into the sample extracting solution containing the coloring agent to remove the surfactant so as to prepare a sample extracting solution without the surfactant; (4) filtering the sample from which the surfactant is removed to prepare a sample liquid to be detected; and (5) adding a carbon quantum dot compound into the sample to-be-detected liquid as a fluorescent probe, and performing fluorescence detection on the colorant. The method for detecting the coloring agent in the children cosmetics based on the biomass carbon quantum dot compound has the advantages of being high in sensitivity, low in cost, easy to operate and the like.

Description

Technical Field

[0001] The present invention belongs to the field of analysis and detection, and in particular relates to a method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds. Background Art

[0002] In 2023, with the release of the "Technical Guidelines for Children's Cosmetics" by the China Food and Drug Inspection Institute, stricter requirements were put forward for the use of colorants in children's cosmetics. For example, when using more than 4 (including 4) colorants, the scientific nature and necessity of the types and amounts of raw materials used should be explained, and relevant research should be carried out to ensure the safety of product use. If necessary, human safety test data should be submitted as evidence support; this is because children's skin is more delicate and sensitive than adults, and the skin barrier function has not yet fully developed, so they are more sensitive to colorants and other ingredients in cosmetics; in addition, since the ratio of children's body surface area to body weight is usually greater than that of adults, children's systemic exposure is higher than that of adults, so the actual safe use concentration of the same raw material in children's cosmetics is in principle lower than the safe use concentration in adult cosmetics. The safety assessment of children's cosmetics also needs to fully consider the characteristics of infants' and young children's behavioral development, such as the possibility that some behaviors (such as sucking, scratching, etc.) lead to higher exposure than adults, and the difference between infants' and young children's metabolic capacity and that of adults.

[0003] At present, the detection methods of colorants in children's cosmetics are mainly divided into the following categories: 1. High performance liquid chromatography (HPLC): HPLC is a commonly used detection method with high sensitivity and good separation effect, suitable for qualitative and quantitative analysis of colorants; however, this method has poor specificity and is difficult to detect trace compounds and distinguish compounds with similar structures. 2. Thin layer chromatography (TLC): TLC is a simple, fast and low-cost qualitative analysis method suitable for preliminary screening and identification of colorants; however, this method has relatively low sensitivity and quantitative ability and is not suitable for high-precision analysis. 3. Gas chromatography (GC):

[0004] GC is suitable for the analysis of volatile colorants and has high sensitivity and high separation efficiency; however, this method is not applicable to non-volatile or thermally unstable colorants, so the detection range is narrow.

[0005] (UV-Vis): UV-Vis is also a simple and low-cost detection method, which can be used for the quantitative analysis of some colorants; however, this method has poor selectivity and is easily interfered by other components in the sample, making it unsuitable for the analysis of complex samples. 5. Atomic absorption spectroscopy (AAS): AAS can provide high sensitivity and high selectivity analysis for certain metal colorants; however, this method usually requires complex pretreatment of the sample and can only analyze specific types of metal elements. 6. Mass spectrometry (MS): MS can provide accurate molecular mass and structural information, and is suitable for qualitative and quantitative analysis of trace colorants in complex samples; however, this method has high equipment costs, high operating technical requirements, and relatively high maintenance costs.

[0006] In summary, there is currently a lack of a detection method for colorants in children's cosmetics that is highly sensitive, simple to operate, and low in cost. In view of this, this patent application is hereby filed. Summary of the invention

[0007] In view of the shortcomings of the current methods for detecting colorants in children's cosmetics, the purpose of the present invention is to provide a method and application for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds.

[0008] In order to achieve the above object, the solution of the present invention is:

[0009] A method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds, the specific steps are as follows:

[0010] (1) adding a surfactant to a mixed solution of ethanol and water, and then adding a base to mix well to obtain an extraction solvent containing the surfactant;

[0011] (2) adding the children's cosmetic sample containing the colorant to the extraction solvent containing the surfactant prepared in step (1), then stirring the obtained mixture evenly and performing microwave heating extraction, and obtaining a sample extract containing the colorant after centrifugal separation;

[0012] (3) adding an inorganic salt to the sample extract containing the colorant obtained in step (2) to remove the surfactant, and obtaining a sample extract from which the surfactant has been removed after centrifugation;

[0013] (4) filtering the sample obtained in step (3) from which the surfactant has been removed to obtain a sample solution;

[0014] (5) Adding a carbon quantum dot compound as a fluorescent probe to the sample solution obtained in step (4), and then adjusting the pH value of the system to perform fluorescence detection of the colorant.

[0015] Preferably, the surfactant described in step (1) is one of long-chain fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether or fatty acid polyoxyethylene ester.

[0016] Preferably, the base in step (1) is one of ammonia, ethylenediamine, triethylamine, isopropylamine, cyclohexylamine or ethanolamine.

[0017] Preferably, the volume ratio of ethanol to water in step (1) is 4:1 to 5:1.

[0018] Preferably, the microwave heating extraction conditions in step (2) are: heating temperature is 60-80° C.; heating time is 15-50 min.

[0019] Preferably, the inorganic salt in step (3) is one of polyaluminium chloride, aluminium sulfate, polyferric sulfate or ferric chloride.

[0020] Preferably, the filtration in step (4) is through a water filter membrane.

[0021] Preferably, the pH value in step (5) is 4-9.

[0022] Preferably, the colorant described in step (5) includes at least one of solvent green 7, acid yellow 1, food yellow 3, orange yellow I, acid orange 7, food red 9, food red 7, food red 17, food red 1, acid red GR, acid orange II, acid red, amaranth, carmine, allura red, lemon yellow, sunset yellow or new red.

[0023] Preferably, the carbon quantum dot compound described in step (5) is a biomass carbon quantum dot compound or a modified biomass carbon quantum dot compound.

[0024] The principle of the method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds provided by the present invention is as follows:

[0025] The method for detecting colorants in children's cosmetics provided by the present invention is a fluorescence analysis detection method based on biomass carbon quantum dot compounds; however, since children's cosmetics have the characteristics of complex matrix composition, most of the target colorants to be detected also have the characteristics of similar structures; therefore, before the fluorescence analysis detection, the test samples need to be effectively pre-treated, which can effectively reduce the interference of complex substrate materials in cosmetic samples on fluorescence analysis tests on the one hand, and on the other hand, can effectively concentrate the colorants contained in the samples, thereby improving the accuracy of the analysis test. Specifically, the formulas of common children's cosmetics are very complex. For example, nail polish, eyeliner, powder and other makeup samples cannot obtain clear supernatant by conventional stirring and dissolving methods or even ultrasonic assisted extraction; therefore, it is difficult to achieve effective separation and accurate analysis of the contained colorants by conventional pretreatment methods. The method provided by the present invention uses a surfactant combined with microwave-assisted extraction, which mainly utilizes the special hydrophilic-lipophilic amphiphilic structure of the surfactant. Therefore, the addition of the surfactant can enhance the solubility of the colorant molecules in the extractant. At the same time, the use of microwave technology for synergistic extraction utilizes the microwave energy to quickly heat the extraction system in a very short time, thereby further enhancing the leaching efficiency and extraction rate of the colorant molecules.

[0026] Compared with the existing detection methods of colorants in children's cosmetics, the method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds provided by the present invention has the following advantages:

[0027] (1) The method for detecting colorants in children's cosmetics provided by the present invention has the advantages of high separation efficiency, high sensitivity and low cost; the detection limit of amaranth red is 23nmol / L, and the detection limit of sunset yellow is 36nmol / L.

[0028] (2) The method for detecting colorants in children's cosmetics provided by the present invention can realize rapid detection of colorants and has the advantages of simple operation and reliable analysis results.

[0029] (3) The method for detecting colorants in children's cosmetics provided by the present invention uses microwave technology for synergistic extraction during the pretreatment process, which not only has high extraction efficiency but also has the advantages of energy saving and environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1The fluorescence spectra of CS-CDs solution after adding different concentrations of amaranth standard solution are shown in Figure 5; wherein, the concentrations of amaranth standard solution corresponding to curves a to p are 0, 2.00, 3.33, 6.67, 10.00, 13.33, 16.67, 20.00, 23.33, 26.67, 30.00, 33.33, 36.67, 40.00, 43.33, 46.67, and 50.00 μmol / L, respectively.

[0033] Figure 2 The fluorescence spectra of the CDs solution after adding different concentrations of sunset yellow standard solution are shown in Figure 5; wherein, the concentrations of sunset yellow standard solution corresponding to curves a to p are 0, 2.00, 3.33, 6.67, 10.00, 13.33, 16.67, 20.00, 23.33, 26.67, 30.00, 33.33, 36.67, 40.00, 43.33, 46.67, and 50.00 μmol / L, respectively.

[0036] Figure 3 This is the UV-Vis spectrum of amaranth solution.

[0037] Figure 4 This is the UV-Vis spectrum of sunset yellow solution. DETAILED DESCRIPTION

[0038] The present invention is further described in detail below with reference to the accompanying drawings and examples. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. The specific mass, reaction time, temperature, process parameters, etc. in the examples are only examples within the appropriate range. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention belong to the scope of protection of the present invention.

[0039] All reagents used were commercial reagents unless otherwise specified and were not further purified before use.

[0040] The raw material ginkgo leaves used to prepare carbon quantum dots are collected from the fallen leaves of ginkgo trees in the applicant's unit. Any leaves can be used as raw materials; the ginkgo leaves need to be simply processed before use. The specific steps are as follows: the collected ginkgo leaves are washed with deionized water and then dried. The dried ginkgo leaves are put into a grinder and ground into powder and passed through a 1000-mesh sieve to obtain ginkgo leaf powder for later use.

[0041] The steps for preparing the carbon quantum dots used in the examples of the present invention are as follows:

[0042] 2.5g of ginkgo leaf powder and 150ml of deionized water were added to a 250ml round-bottom flask and stirred at room temperature for 0.5h. The round-bottom flask was sealed and moved into an ultrasonic reactor for ultrasonic oscillation reaction at 85℃ (80kHz, 100w) for 1h. After the reaction was completed, it was naturally cooled to room temperature. After standing for 45min, the above solution was taken into a centrifuge tube and centrifuged at a speed of 1500r / min for 0.5h. Then the obtained solution was passed through a dialysis membrane with a molecular cutoff of 3500Da to obtain a yellow transparent carbon quantum dot solution. Finally, the carbon quantum dot solution obtained after dialysis was freeze-dried to obtain a light yellow solid, which was carbon quantum dots, recorded as CDs. A certain amount of the obtained carbon quantum dot CDs was weighed and prepared into a solution with a mass concentration of 10mg / mL using deionized water for standby use.

[0043] The preparation steps of the water-soluble carboxymethyl chitosan modified carbon quantum dots used in the examples of the present invention are as follows:

[0044] 5g of ginkgo leaf powder, 3g of sodium hydroxide, 1.6g of water-soluble carboxymethyl chitosan and 300ml of deionized water were added to a 500ml round-bottom flask and stirred at room temperature for 0.5h. The round-bottom flask was sealed with a rubber stopper and moved into an ultrasonic reactor for ultrasonic oscillation reaction at 85℃ (80kHz, 100w) for 1.5h. After the reaction was completed, it was naturally cooled to room temperature. After standing for 45min, the above solution was taken into a centrifuge tube and centrifuged at a speed of 1500r / min for 0.5h. The obtained solution was then passed through a dialysis membrane with a molecular cutoff of 3500Da to obtain a yellow transparent carbon quantum dot solution. Finally, the carbon quantum dot solution obtained after dialysis was freeze-dried to obtain a light yellow solid, which was a water-soluble carboxymethyl chitosan-modified carbon quantum dot, recorded as CS-CDs. A certain amount of the obtained solid CS-CDs was weighed and prepared into a solution with a mass concentration of 10mg / mL using deionized water for standby use.

[0045] The samples used in the embodiments of the present invention are artificially simulated positive samples. This is because the colorant content in the commercially available children's cosmetics samples is different, and the actual samples are not suitable for detecting and analyzing the content of the colorant. Therefore, the specific preparation process of the positive children's cosmetics samples used in the embodiments of the present invention is: add a colorant (sunset yellow or amaranth red) to 5g of a negative children's cosmetics sample (children's nail polish) to ensure that the amount of colorant added in the positive sample is 100μmol / L.

[0046] The preparation and fluorescence test method of the sunset yellow standard solution used in the embodiment of the present invention are as follows:

[0047] Accurately weigh 1g of sunset yellow sample and dissolve it in distilled water to prepare a stock solution with a concentration of 100mg / kg, and dilute it appropriately when used. The determination method of sunset yellow sample is as follows: add sunset yellow solution of different concentrations to the sample tube, then add 1mL of disodium hydrogen phosphate-citrate buffer solution (0.1mol / L, pH=6.6) and 100μL of fluorescent CDs solution, and then add distilled water to a total volume of 4mL; after vortexing the mixture, let it stand at room temperature for 2 minutes to perform fluorescence testing, and perform fluorescence intensity F test under the conditions of maximum excitation wavelength of 345nm, maximum emission wavelength of 412nm, and slit width of 10nm; calculate the fluorescence quenching rate ΔF according to the formula ΔF=(F0-F) / F0, where F0 is the fluorescence intensity of the blank control group (sunset yellow standard solution); the fluorescence quenching of CDs was measured when the concentration of sunset yellow increased from 0 to 50μmol / L, and the results are as follows Figure 1 shown by Figure 1 It can be seen that the fluorescence intensity ratio of CDs before and after adding sunset yellow (F0 / F) is linearly related to the sunset yellow concentration c in the range of 0-50 μmol / L, the correlation coefficient (r) is 0.9993, and the linear regression equation is F0 / F=0.0754c+0.6947; then, based on the ratio of 3 times the blank standard deviation (σ) of 15 measurements and the slope of the linear regression equation, it is calculated that the detection limit of sunset yellow using CDs as a fluorescent probe is 36 nmol / L.

[0048] The preparation and fluorescence test method of the amaranth red standard solution used in the embodiment of the present invention are as follows:

[0049] Accurately weigh 1g of amaranth sample and dissolve it in distilled water to prepare a stock solution with a concentration of 100mg / kg, and dilute it appropriately when used. The determination method of amaranth sample is as follows: add amaranth solution of different concentrations and 100μL CS-CDs stock solution to the sample tube, then add 1mL disodium hydrogen phosphate-sodium dihydrogen phosphate solution (0.1mol / L, pH=6.0), and then add distilled water to a total volume of 4mL; after vortexing the mixture, let it stand at room temperature for 5 minutes before performing a fluorescence test. Under the conditions of maximum excitation wavelength of 380nm, maximum emission wavelength of 425nm, and slit width of 10nm, perform a fluorescence intensity F test; calculate the fluorescence quenching rate ΔF according to the formula ΔF=(F0-F) / F0, where F0 is the fluorescence intensity of the blank control group (amaranth standard solution); the fluorescence quenching of CS-CDs was measured when the amaranth concentration increased from 0 to 50μmol / L, and the results are as follows Figure 2 shown by Figure 2It can be seen that the fluorescence intensity ratio of CS-CDs before and after adding amaranth red (F0 / F) is linearly related to the amaranth red concentration c in the range of 0-50 μmol / L, the correlation coefficient (r) is 0.9995, and the linear regression equation is F0 / F=0.0871c+0.8122; then based on the ratio of 3 times the blank standard deviation (σ) of 15 measurements and the slope of the linear regression equation, it is calculated that the detection limit of amaranth red using CS-CDs as a fluorescent probe is 23 nmol / L.

[0050] Embodiment 1:

[0051] The detection steps for colorants (sunset yellow) in children's cosmetics are as follows:

[0052] (1) adding 0.2 g of long-chain fatty alcohol polyoxyethylene ether to a mixed solution consisting of 100 mL of ethanol and 20 mL of water, and then adding 0.1 g of ethylenediamine and mixing well to obtain an extraction solvent containing long-chain fatty alcohol polyoxyethylene ether;

[0053] (2) adding 2.0 g of a children's nail polish sample containing sunset yellow to the extraction solvent containing a surfactant prepared in step (1), and then stirring the resulting mixture evenly and performing microwave heating extraction, setting the microwave power to 400 W, the heating temperature to 65° C., the heating extraction time to 35 min, and obtaining a sample extract containing a colorant after centrifugal separation;

[0054] (3) adding 50 mg of polyaluminium chloride to the sample extract containing sunset yellow obtained in step (2), stirring the resulting mixture at room temperature for 0.5 h, and then centrifuging to remove insoluble matter to obtain a sample extract from which the surfactant has been removed;

[0055] (4) The sample obtained in step (3) from which the surfactant has been removed is filtered through a 0.45 μm water filter membrane to obtain a purified sample solution; 1 mL of the purified sample solution is diluted with a 0.1 mol / L hydrochloric acid solution and fixed to 10 mL, and then a sample is taken and the absorbance at 481 nm is measured using an ultraviolet-visible (UV-Vis) spectrophotometer, and then the extraction rate is calculated; the specific conditions of the UV-Vis test are as follows: the spectrophotometer used is a Shimadzu UV-VIS spectrophotometer UV-2500, the cuvette length is 1 cm, and the wavelength scanning range is 330-600 nm; the absorbance A0 of the sunset yellow standard solution is 0.337, and the absorbance A1 of the purified sample solution is 0.243; the extraction rate E = (A1 / A0) × 100%; the result E1 = 72%; Figure 3 This is the UV-Vis spectrum of the purified sunset yellow sample test solution. Figure 3 It can be seen that Sunset Yellow has absorption in the range of 350-550nm, and its maximum absorption peak is at 481nm;

[0056] (5) After diluting the purified sample solution obtained in step (4) by 10 times with water, 100 uL of carbon quantum dot CDs solution was added, and then the pH value was adjusted to 6.6 with disodium hydrogen phosphate-citric acid buffer solution. After mixing evenly for 5 minutes, the fluorescence intensity was measured. Three groups were measured in parallel, and the fluorescence analysis result was: 72.44 μmol / L.

[0057] Embodiment 2:

[0058] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the long-chain fatty alcohol polyoxyethylene ether in step (1) is replaced with alkylphenol polyoxyethylene ether; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E2=69%; fluorescence analysis result: 69.13μmol / L.

[0059] Embodiment 3:

[0060] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the ethylenediamine in step (1) is replaced with triethylamine; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E3 = 74%; fluorescence analysis result: 74.60 μmol / L.

[0061] Embodiment 4:

[0062] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the ethylenediamine in step (1) is replaced with ethanolamine; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E4=78%; fluorescence analysis result: 78.25μmol / L.

[0063] Embodiment 5:

[0064] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the conditions for microwave heating extraction in step (2) are changed to: setting the microwave power to 450 W, the heating temperature to 80° C., and the heating extraction time to 15 min; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E5=84%; fluorescence analysis result: 84.51 μmol / L.

[0065] Embodiment 6:

[0066] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the amount of long-chain fatty alcohol polyoxyethylene ether in step (1) is changed to 0 g; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E6 = 47%; fluorescence analysis result: 47.64 μmol / L.

[0067] Embodiment 7:

[0068] The detection steps of the colorant (sunset yellow) in children's cosmetics refer to Example 1, except that the ethylenediamine in step (1) is replaced with ethanolamine; the conditions of microwave heating extraction in step (2) are changed to: setting the microwave power to 450 W, the heating temperature to 80° C., and the heating extraction time to 15 min; the remaining steps are all referred to Example 1, and the results are as follows: extraction rate E7=91%; fluorescence analysis result: 91.96 μmol / L.

[0069] Embodiment 8:

[0070] The detection steps of the colorant (amaranth) in children's cosmetics refer to Example 1, except that the ethylenediamine in step (1) is replaced by ethanolamine; the children's nail polish sample containing sunset yellow in step (2) is replaced by a children's nail polish sample containing amaranth, and the microwave heating extraction conditions are changed to: setting the microwave power to 450 W, the heating temperature to 80° C., and the heating extraction time to 15 min; the CDs solution in step (5) is replaced by a CS-CDs solution, and the pH value is adjusted to 6.6 using a disodium hydrogen phosphate-citric acid buffer solution is changed to adjusting the pH value to 6.0 using a disodium hydrogen phosphate-sodium dihydrogen phosphate buffer solution; the remaining steps are all referred to Example 1, and the results are as follows: the amaranth extraction rate E8=89%; the fluorescence analysis result is: 89.73 μmol / L. Figure 4 The UV-Vis spectrum of the purified amaranth sample solution. Figure 4 It can be seen that amaranth has absorption in the range of 350-550nm, and its maximum absorption peak is at 528nm.

Claims

1. A method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds, characterized in that: The specific steps are as follows: (1) adding a surfactant to a mixed solution of ethanol and water, and then adding a base to mix well to obtain an extraction solvent containing the surfactant; (2) adding the children's cosmetic sample containing the colorant to the extraction solvent containing the surfactant prepared in step (1), then stirring the obtained mixture evenly and performing microwave heating extraction, and obtaining a sample extract containing the colorant after centrifugal separation; (3) adding an inorganic salt to the sample extract containing the colorant obtained in step (2) to remove the surfactant, and obtaining a sample extract from which the surfactant has been removed after centrifugation; (4) filtering the sample obtained in step (3) from which the surfactant has been removed to obtain a sample solution; (5) Adding a carbon quantum dot compound as a fluorescent probe to the sample solution obtained in step (4), and then adjusting the pH value of the system to perform fluorescence detection of the colorant.

2. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The surfactant described in step (1) is one of long-chain fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether or fatty acid polyoxyethylene ester.

3. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The base described in step (1) is one of ammonia water, ethylenediamine, triethylamine, isopropylamine, cyclohexylamine or ethanolamine.

4. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The volume ratio of ethanol to water in step (1) is 4:1 to 5:

1.

5. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The microwave heating extraction conditions described in step (2) are: heating temperature is 60-80° C.; heating time is 15-50 min.

6. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The inorganic salt described in step (3) is one of polyaluminium chloride, aluminium sulfate, polyferric sulfate or ferric chloride.

7. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The filtration described in step (4) is through a water filter membrane.

8. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The pH value described in step (5) is 4-9.

9. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The colorant described in step (5) includes at least one of solvent green 7, acid yellow 1, food yellow 3, orange yellow I, acid orange 7, food red 9, food red 7, food red 17, food red 1, acid red GR, acid orange II, acid red, amaranth, carmine, allura red, lemon yellow, sunset yellow or new red.

10. The method for detecting colorants in children's cosmetics based on biomass carbon quantum dot compounds according to claim 1, characterized in that: The carbon quantum dot compound described in step (5) is one of a biomass carbon quantum dot compound or a modified biomass carbon quantum dot compound.

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