A method for extracting and detecting polyaminopropyl biguanide in cosmetics and raw materials

Abstract

The application discloses a kind of cosmetics and raw material polyaminopropyl biguanide extraction method and detection method, the extraction method includes the following steps: step one, respectively, sodium tetraborate, sodium dodecyl sulfate is weighed, after dissolving with water, mix, as separation buffer solution;Separation buffer solution is diluted with water and used as sample extraction solution;Step two, sample extraction solution is used to process sample, and the sample solution to be measured is obtained.The detection method includes the following steps: step one, preparation standard stock solution, standard series solution;Step two, the sample solution to be measured and standard series solution are connected to capillary micellar electrokinetic chromatography system and detected.The extraction method and MEKC detection method provided by the application can greatly make up for the defects in the prior art, such as the difference between polyaminopropyl biguanide molecules with different polymerization degrees, which leads to multiple chromatographic peaks in liquid chromatography, and the response difference is close to 10 times, and the result is close to the true value, with wide application prospect and good market potential.

Description

Technical Field

[0001] This invention relates to the field of polyaminopropyl biguanide detection technology, and in particular to a method for extracting and detecting polyaminopropyl biguanide in cosmetics and raw materials. Background Technology

[0002] Polyaminopropyl biguanide (PAPB) is a biguanide cationic surfactant and is a permitted preservative under my country's "Cosmetic Safety Technical Specifications" (2015 edition), which stipulates a maximum permissible concentration of 0.3% for use in cosmetics. Annex V of the EU Cosmetic Regulation (EC) 1223 / 2009 specifies a maximum permissible amount of PAPB as a preservative in cosmetics of 0.3%. Japan's "Cosmetic Standards" specifies a maximum permissible amount of 0.1% for use as a preservative in cosmetics. On April 7, 2017, the EU's SCCS adopted a new opinion, stating that based on the provided data, a maximum permissible amount of PAPB as a preservative in cosmetics of no more than 0.1% is safe, but its use in sprayable formulations is not recommended.

[0003] Polyaminopropyl biguanide (PPBQ) possesses potent broad-spectrum bactericidal activity and is widely used in disinfectants, detergents, contact lens solutions, makeup remover wipes, toothpaste, toners, and makeup removers. It exhibits strong inhibitory effects against both difficult-to-treat Gram-positive and Gram-negative bacteria and shows good efficacy against citrus stem rot. Currently, the 2015 edition of my country's "Cosmetic Hygiene Standards" uses liquid chromatography for quantitative analysis of PPBQ. However, there are few domestic and international publications on the content determination of PPBQ, with only one article available. [1] Determination of polyaminopropyl biguanide in corneal contact lens solution using solid-phase extraction-high performance liquid chromatography (SPE-HPLC) (1 paper) [2] High-performance liquid chromatography (HPLC) was used to determine polyaminopropyl biguanide (PPBG) in cosmetics. In summary, current standards and related literature all employ HPLC. However, because PPBG is a mixture of polymers with varying degrees of polymerization, differences in average molecular weight and molecular weight distribution lead to multiple chromatographic peaks in HPLC from different sources, with response differences as high as 5-fold, making accurate quantification of PPBG in cosmetics impossible. Furthermore, cosmetic matrices are complex, and raw materials contain numerous impurities; no quantitative detection methods for PPBG in cosmetic raw materials have been reported in the literature.

[0004] [1] Liu Xi, Cui Yongping. Determination of polyaminopropyl biguanide in corneal contact lens solution by solid phase extraction-high performance liquid chromatography [J]. Capital Food and Medicine, 2015, 22(12):82-84.

[0005] [2] Chen Jing, Jian Longhai, Mao Beiping, et al. Quantitative determination of polyaminopropyl biguanide in cosmetics by high performance liquid chromatography [J]. Shanghai Journal of Preventive Medicine, 2021, 33(4):349-354. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for extracting and detecting polyaminopropyl biguanide in cosmetics and raw materials.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The first aspect is to provide a method for extracting polyaminopropyl biguanide from cosmetics and raw materials, including the following steps:

[0009] Step 1: Weigh out sodium tetraborate and sodium dodecyl sulfate separately, dissolve them in water, mix well, and use as a separation buffer solution; dilute the separation buffer solution with water and use it as the sample extraction solution.

[0010] Step 2, Liquid Sample Processing: Accurately weigh the sample, add the sample extract, make up to volume, mix well, and use as the sample solution to be tested;

[0011] Sample processing for creams, lotions, gels, and powders: Accurately weigh the sample, add the sample extract, vortex to mix thoroughly, extract by sonication, then make up to volume with the sample extract, shake well, centrifuge, take the supernatant and filter it through a filter membrane, and use the filtrate as the sample solution to be tested.

[0012] Furthermore, the separation buffer solution contains sodium tetraborate at a concentration of 20 mmol / L and sodium dodecyl sulfate at a concentration of 30 mmol / L; the separation buffer solution is diluted 10 times with water and then used as the sample extraction solution.

[0013] Furthermore, the vortex oscillation time is 30s, the ultrasonic extraction time is 20min, the centrifugation is performed at 10000r / min for 5min, and the average pore size of the filter membrane is 0.22μm.

[0014] The second aspect is to provide a method for detecting polyaminopropyl biguanide in cosmetics and raw materials, wherein the sample extraction method adopts the extraction method for polyaminopropyl biguanide in cosmetics and raw materials as described above, including the following steps:

[0015] Step 1: Accurately weigh polyurethane biguanide standard, dissolve and dilute to volume with water, shake well, and prepare standard stock solution; dilute the standard stock solution stepwise with sample extraction solution to prepare standard series solutions.

[0016] Step 2: Connect the sample solution to be tested and the standard series solutions to the capillary micelle electrochromatography system for detection.

[0017] Furthermore, the conditions for capillary micelle electrokinetic chromatography are as follows:

[0018] Capillary: Fused silica capillary, 40 / 50.2cm, 50μm inner diameter;

[0019] Operating temperature: 25℃;

[0020] Detection wavelength: 235nm;

[0021] Window slit: 100×800μm;

[0022] Separation voltage: 25kV;

[0023] Injection pressure and time: 0.5 psi, 20 s.

[0024] Furthermore, the capillary rinsing steps for capillary micelle electrokinetic chromatography are as follows: before using a new capillary, rinse it with sodium hydroxide solution for 20 min, water for 5 min, and separation buffer solution for 5 min; before each injection, rinse it with sodium hydroxide solution for 2 min, water for 2 min, and separation buffer solution for 2 min in sequence to ensure the reproducibility of migration time and correction peak area.

[0025] Furthermore, the concentration of the sodium hydroxide solution is 1 mol / L.

[0026] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0027] By using the novel extraction method designed in this invention, polyaminopropyl biguanide can be extracted quickly, completely, and accurately from cosmetics and raw materials for different matrix types. Compared with existing methods, this method has the following advantages: According to the results of previous market research on cosmetic samples, polyaminopropyl biguanide is mostly found in toners and makeup removers. According to the extraction method designed in this invention, liquid (water) matrices can be directly injected after dilution with the sample extract, which greatly saves the sample pretreatment time.

[0028] In addition, this method uses MEKC separation mode, which encapsulates polyurethane biguanide into large molecular clusters through micelles, reducing the differences between polyurethane biguanide molecules with different degrees of polymerization. This method can achieve the same result for polyurethane biguanide from different sources, with only one peak and no significant differences in retention time and response.

[0029] In summary, the method of this invention can achieve accurate quantification of polyaminopropyl biguanide, and the pretreatment operation is simple, easy to operate, highly versatile, and has good reproducibility, making it suitable for the popularization and application of the method among laboratories.

[0030] The extraction method and MEKC detection method provided by this invention can significantly overcome the shortcomings of existing technologies, such as the differences in polymerization degree of polyaminopropyl biguanide molecules leading to multiple chromatographic peaks in liquid chromatography and response differences approaching 10 times. In particular, it solves the technical problem that existing methods cannot accurately quantify polyaminopropyl biguanide in cosmetics and raw materials. The results of determining polyaminopropyl biguanide in cosmetics and raw materials using this method are close to the true values; therefore, it has broad application prospects and good market potential. Attached Figure Description

[0031] Figure 1 Capillary electrophoresis image of PAPB standard (30 μg / ml).

[0032] Figure 2 This is a capillary electrophoresis image of a positive sample containing polyurethane-propyl biguanide. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0034] The first aspect of this invention is to provide a method for extracting polyaminopropyl biguanide from cosmetics and raw materials, the specific technical solution of which is as follows:

[0035] 1. Reagents and Materials

[0036] Unless otherwise specified, all reagents used in this method are of analytical grade or higher, and the water is Grade I water as specified in GB / T 6682.

[0037] 1.1 Standard samples, see Appendix A (Table 1).

[0038] Table 1

[0039]

[0040] 1.2 Sodium hydroxide (NaOH), analytical grade.

[0041] 1.3 Sodium tetraborate (Na2B4O7), analytical grade.

[0042] 1.4 Sodium dodecyl sulfate (SDS), analytical grade.

[0043] 1.5 Separation buffer solution (20 mmol / L sodium tetraborate + 30 mmol / L sodium dodecyl sulfate): Weigh 4.02 g sodium tetraborate (1.3) and 8.65 g sodium dodecyl sulfate (1.4) respectively, dissolve them in an appropriate amount of water, and make up to 1 L. Mix well to prepare the separation buffer solution.

[0044] 1.6 Sample extraction solution: Dilute the separation buffer solution (1.5) with water 10 times.

[0045] 1.7 Sodium hydroxide solution (1 mol / L): Accurately weigh 40 g of sodium hydroxide (1.2), add 1000 mL of ultrapure water to dissolve and mix well.

[0046] 1.8 Standard stock solution: Accurately weigh 50 mg of polyaminopropyl biguanide standard, place it in a 10 mL volumetric flask, dissolve it in water and dilute to the mark, shake well, and prepare a standard stock solution with a concentration of 5 g / L. Store it in a refrigerator at 4 °C.

[0047] 1.9 Standard series solutions: The standard stock solution (1.8) was serially diluted with the sample extraction solution (1.6) to prepare standard series solutions of 1 mg / L, 5 mg / L, 10 mg / L, 30 mg / L, 60 mg / L and 120 mg / L respectively.

[0048] 2. Instruments and Equipment

[0049] 2.1 The SCIEX PA 800Plus drug analysis system features a diode array detector (PDA);

[0050] 2.2 Analytical balance: sensitivity 0.0001g and 0.00001g;

[0051] 2.3 High-speed centrifuge (speed ≥ 10000 rpm);

[0052] 2.4 Vortex mixer;

[0053] 2.5 Ultrasonic cleaner;

[0054] 2.6 Ultrapure water system.

[0055] 3. Sample processing

[0056] 3.1 Liquid (water)

[0057] Accurately weigh 1.0 g of sample (accurate to 0.0001 g), place it in a 10 ml stoppered colorimetric tube, add sample extract (1.6) to a final volume of 10 mL, shake well and inject directly, while simultaneously performing a blank test.

[0058] 3.2 Creams, lotions, gels, and powders

[0059] Accurately weigh 1.0 g of sample (accurate to 0.0001 g), place it in a 10 ml stoppered colorimetric tube, add 8 mL of sample extraction solution (1.6), vortex for 30 s to ensure the sample and extraction solvent are thoroughly mixed, sonicate for 20 min, dilute to 10 mL with sample extraction solution (1.6), shake well, centrifuge at 10000 r / min for 5 min, filter the solution through a 0.22 μm filter membrane, and use the filtrate as the test solution. At the same time, perform a blank test.

[0060] The second aspect of the present invention is to provide a capillary micelle electrochromatography (MEKC) detection method for polyaminopropyl biguanide in cosmetics and raw materials. The method first uses the extraction method described in the first aspect of the present invention to obtain a sample solution and a series of standard solutions containing polyaminopropyl biguanide, which are then connected to a capillary micelle electrochromatography system for detection.

[0061] Capillary micelle electrokinetic chromatography determination conditions:

[0062] Capillary: Fused silica capillary (PN.338451): 40 / 50.2cm (effective / total length), 50μm inner diameter;

[0063] Operating temperature: 25℃;

[0064] Detection wavelength: 235nm;

[0065] Window slit: 100×800μm;

[0066] Separation voltage: 25kV;

[0067] Injection pressure and time: 0.5 psi, 20 s.

[0068] Capillary flushing procedure: Before use, new capillaries are flushed with sodium hydroxide solution (1 mol / L) (1.7) for 20 min, water for 5 min, and separation buffer solution (1.5) for 5 min. Before each injection, the capillaries are flushed sequentially with sodium hydroxide solution (1 mol / L) (1.7) for 2 min, water for 2 min, and separation buffer solution (1.5) for 2 min to ensure the reproducibility of migration time and correction peak area.

[0069] Example 1

[0070] Positive sample spiked assay: Two cosmetics and raw materials containing polyaminopropyl biguanide (matrix types: liquid (water) and gel, respectively) were selected and subjected to positive spiked assay (standard source: CAS No. 133029-32-0, purity 99.3%, purchased from Yuanye Biotechnology Co., Ltd.). An equivalent amount of the analyte to be added to the raw material was added, and the recovery rate was determined. See Table 2 for sample information.

[0071] Table 2

[0072]

[0073] 1. Instruments and reagents

[0074] The system included a SCIEX PA 800Plus pharmaceutical analysis system with a diode array detector (PDA); Sartorius CP224S and 225D-1CN electronic balances (Sartorius); a 5800 ultrasonic analyzer (BRANSON); an MS3 vortex mixer (IKA); a 5810R benchtop centrifuge (Eppendof); and a Milli-Q Reference A+ ultrapure water system (Millipore).

[0075] Standard: CAS No. 133029-32-0, purity 99.3%, purchased from Yuanye Biotechnology Co., Ltd.

[0076] Sodium tetraborate (Na2B4O7, analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.), sodium hydroxide (NaOH, analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.), sodium dodecyl sulfate (SDS, analytical grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.).

[0077] 2. Methods

[0078] 2.1 Preparation of standard working solutions

[0079] Accurately weigh 50 mg of PAPB standard, place it in a 10 mL volumetric flask, dissolve it in water and dilute to the mark, shake well, and prepare a standard stock solution with a concentration of 5 g / L. Store in a refrigerator at 4 °C.

[0080] Preparation of standard working solutions: The standard stock solution was serially diluted with sample extraction solution (1.6) to prepare standard working solutions with concentrations of 1 mg / L, 5 mg / L, 10 mg / L, 30 mg / L, 60 mg / L and 120 mg / L respectively.

[0081] 2.2 Capillary micelle electrokinetic chromatography conditions

[0082] Capillary: Fused silica capillary (PN.338451): 40 / 50.2 cm (effective / total length), 50 μm inner diameter; Operating temperature: 25℃; Detection wavelength: 235 nm; Window slit: 100 × 800 μm. Separation voltage: 25 kV; Injection pressure and time: 0.5 psi, 20 s.

[0083] Capillary rinsing procedure: Before use, new capillaries should be rinsed with 1 mol / L NaOH for 20 min, water for 5 min, and separation buffer (1.5) for 5 min. Before each injection, the capillaries should be rinsed with 1 mol / L NaOH for 2 min, water for 2 min, and separation buffer (1.5) for 2 min to ensure the reproducibility of migration time and correction peak area.

[0084] Linear regression analysis was performed with peak area as the ordinate (y) and concentration as the abscissa (x, μg / mL), and the linear equation was obtained as follows.

[0085] Table 3

[0086]

[0087] Sample solution preparation for gel-positive sample spike recovery: Take 1 g of polyaminopropyl biguanide positive cosmetic sample (accurate to 0.001 g), and accurately add an equivalent amount of polyaminopropyl biguanide standard to the sample. Place the sample in a 10 mL stoppered colorimetric tube, add 8 mL of sample extract, vortex for 30 s to ensure thorough mixing, and sonicate for 20 min. Dilute to 10 mL with the sample extract, shake well, centrifuge at 10000 r / min for 5 min, and filter the solution through a 0.22 μm filter membrane. Use the filtrate as the test solution. Prepare the test solution according to the above method, and repeat the experiment 6 times for each spike level. Calculate the recovery rate and relative standard deviation (n = 6).

[0088] Sample solution preparation for positive control of liquid (water) raw materials: Take 1 g of raw material containing polyaminopropyl biguanide (accurate to 0.001 g), and accurately add an equivalent amount of polyaminopropyl biguanide standard to each sample. Place the solutions in a 10 mL stoppered colorimetric tube, add the sample extract to a final volume of 10 mL, and shake well. This is the test solution. Prepare the test solution according to the method, which is the recovery solution. Repeat the experiment 6 times for each spiking level, and calculate the recovery rate and relative standard deviation (n=6).

[0089] The calculation of polyaminopropyl biguanide in cosmetics and raw materials is performed according to formula (1):

[0090] (1)

[0091] In the formula: ω—the content of polyurethane-propyl biguanide in cosmetics, %;

[0092] m—sample amount, g;

[0093] ρ — the mass concentration of polyurethane-propyl biguanide calculated by substituting into the standard curve, in μg / mL;

[0094] V – Fixed volume, mL.

[0095] Under chromatographic conditions, the standard working curve solution and the sample solution are injected separately, and qualitative analysis is performed based on the retention time and the spectrum obtained from the diode array. The content of polyaminopropyl biguanide in the sample solution is then determined from the standard curve. The response value of polyaminopropyl biguanide in the sample solution should be within the linear range of the standard curve. If it exceeds the linear range, the extract should be diluted before testing or the volume of the extract should be increased before retesting.

[0096] The results of the positive spike recovery rate determination are shown in Table 4, indicating that the recovery rate determination yielded satisfactory results.

[0097] Table 4

[0098]

[0099] Example 2

[0100] Blank sample spiked determination: Take blank matrix samples of creams and powders without polyurethane biguanide and perform blank spiked tests on them (standard source: CAS No. 133029-32-0, purity 98.15%, purchased from AMP Company), and determine the recovery rate results.

[0101] The detection method is the same as in Example 1.

[0102] Linear regression analysis was performed with peak area as the ordinate (y) and concentration as the abscissa (x, μg / mL), and the linear equations are shown in Table 5 below.

[0103] Table 5

[0104]

[0105] Sample preparation for blank sample spike recovery: Weigh 1g (accurate to 0.001g) of blank matrix sample for creams, lotions, and powders into 10mL stoppered colorimetric tubes. Accurately add a certain amount of polyaminopropyl biguanide standard, then add 8mL of sample extract. Vortex for 30s to ensure thorough mixing of the sample and extraction solvent. Sonicate for 20min. Dilute to 10mL with the sample extract, shake well, and centrifuge at 10000r / min for 5min. Filter the solution through a 0.22μm filter membrane. Use the filtrate as the test solution. Repeat the experiment 6 times for each spike level and calculate the recovery rate and relative standard deviation (n=6).

[0106] The results of the recovery determination of the blank matrix spiked with spiked reagent are shown in Table 6. The results show that the recovery determination yielded satisfactory results.

[0107] Table 6

[0108]

[0109] Example 3

[0110] 1. Compare the differences in the responses of three different sources of polyurethane propyl biguanide standards in capillary micelle electrokinetic chromatography. The information on the standards is shown in Table 7.

[0111] Table 7

[0112]

[0113] Standards: 1. CAS No.: 133029-32-0, purity 99.3%, purchased from Yuanye Biotechnology Co., Ltd.; 2. CAS No.: 133029-32-0, purity 98.15%, purchased from Anpu Company; 3. CAS No.: 133029-32-0, purity 99.13%, purchased from Macklin Company.

[0114] 2. Extraction and testing were performed on cosmetic A (containing polyaminopropyl biguanide) from factory A and raw material B (containing polyaminopropyl biguanide) from factory B (Table 8): The labeled content of polyaminopropyl biguanide in cosmetic A was 0.2%; the labeled content of polyaminopropyl biguanide in raw material B was 0.2%.

[0115] Table 8

[0116]

[0117] Preparation of three different sources of polyaminopropyl biguanide standards: Accurately weigh 50 mg of each of the three different sources of polyaminopropyl biguanide standards, place them in 10 mL volumetric flasks, dissolve them in water and dilute to the mark, shake well, and prepare standard stock solutions with a concentration of 5 g / L for each standard. Store at 4°C. Dilute the standard stock solutions with sample extraction solutions to prepare standard working solutions with a concentration of 120 mg / L.

[0118] Sample processing

[0119] Cosmetic A: Accurately weigh 1.0g of sample (accurate to 0.0001g), place it in a 10ml stoppered colorimetric tube, add sample extract (1.6) to make up to 10mL, shake well and inject directly, while performing a blank test at the same time.

[0120] Raw material B: Accurately weigh 1.0 g of sample (accurate to 0.0001 g), place it in a 10 ml stoppered colorimetric tube, add 8 mL of sample extraction solution (1.6), vortex for 30 s to ensure the sample and extraction solvent are thoroughly mixed, sonicate for 20 min, dilute to 10 mL with sample extraction solution (1.6), shake well, centrifuge at 10000 r / min for 5 min, filter the solution through a 0.22 μm filter membrane, use the filtrate as the test solution, and perform a blank test at the same time.

[0121] The responses of polyurethane-propyl biguanide standards from different sources in CE are shown in Table 9. The detection method described in this invention can achieve no significant difference in response among different standards.

[0122] Table 9

[0123]

[0124] The sample determination results are shown in Table 10. The extraction method and rapid determination method described in this invention can accurately quantify the content of polyaminopropyl biguanide in cosmetics and raw materials.

[0125] Table 10

[0126]

[0127] In summary, the detection method for polyaminopropyl biguanide in cosmetics and raw materials of this invention is simple, rapid, and highly sensitive, with recovery rate and repeatability meeting the requirements of routine testing. This method features high sensitivity, high quality accuracy, and a feasible linear range, enabling accurate quantification of polyaminopropyl biguanide and significantly improving the monitoring capabilities of testing institutions for cosmetics.

[0128] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the content and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting polyaminopropyl biguanide in cosmetics and raw materials, characterized in that, Includes the following steps: Step 1: Weigh out sodium tetraborate and sodium dodecyl sulfate separately, dissolve them in water, and mix well to prepare a separation buffer solution; dilute the separation buffer solution 10 times with water to prepare the sample extraction solution; the concentration of sodium tetraborate in the separation buffer solution is 20 mmol / L and the concentration of sodium dodecyl sulfate is 30 mmol / L. Step 2, Liquid Sample Processing: Accurately weigh the sample, add the sample extract, make up to volume, mix well, and use as the sample solution to be tested; Creams, lotions, gels, and powders: Accurately weigh the sample, add the sample extraction solution, vortex to mix thoroughly, extract by sonication, then make up to volume with the sample extraction solution, shake well, centrifuge, take the supernatant and filter it through a filter membrane, and use the filtrate as the sample solution to be tested. Step 3: Accurately weigh the polyurethane-propyl biguanide standard, dissolve it in water and dilute to volume, shake well, and prepare the standard stock solution; The standard stock solution was diluted stepwise with the sample extraction solution to prepare a series of standard solutions; Step 4: Connect the sample solution to be tested and the standard series solutions to the capillary micelle electrochromatography system for detection; The conditions for capillary micelle electrokinetic chromatography determination are as follows: Capillary: Fused silica capillary, 40 / 50.2cm, 50μm inner diameter; Operating temperature: 25℃; Detection wavelength: 235nm; Window slit: 100×800μm; Separation voltage: 25kV; Injection pressure and time: 0.5 psi, 20 s.

2. The method for detecting polyaminopropyl biguanide in cosmetics and raw materials according to claim 1, characterized in that, The vortex oscillation time is 30s, the ultrasonic extraction time is 20min, the centrifugation is performed at 10000r / min for 5min, and the average pore size of the filter membrane is 0.22μm.

3. The method for detecting polyaminopropyl biguanide in cosmetics and raw materials according to claim 1, characterized in that, The capillary rinsing procedure for capillary micelle electrokinetic chromatography is as follows: before using a new capillary, rinse it with sodium hydroxide solution for 20 min, water for 5 min, and separation buffer solution for 5 min. Before each injection, rinse it with sodium hydroxide solution for 2 min, water for 2 min, and separation buffer solution for 2 min to ensure the reproducibility of migration time and correction peak area.

4. The method for detecting polyaminopropyl biguanide in cosmetics and raw materials according to claim 3, characterized in that, The concentration of the sodium hydroxide solution is 1 mol / L.

Images