A method for determining the fatty acid soap content in fatty acyl amino acid salt products

Abstract

The invention discloses a method for determining the fatty acid / soap content in a fatty acyl amino acid / salt product, and belongs to the technical field of quantitative analysis of components of fine chemical products. The method for determining the fatty acid / soap content in a fatty acyl amino acid / salt product of the invention comprises: using a cationic surfactant as an associating agent and bromocresol green as an indicator; using an indicator buffer, a low-carbon alcohol, an inorganic salt, and a chloroalkane as a mixed medium; under a pH of 10 to 12.5, dripping the associating agent into a mixed solution formed by a fatty acyl amino acid / salt product test solution and the mixed medium; shaking the mixed solution to quickly distribute and balance until the indicator is completely transferred from the aqueous phase to the chloroalkane phase and turns sky blue, recording the volume of the consumed associating agent solution, and calculating the fatty acid / soap content according to the concentration of the associating agent, the dilution ratio of the sample, and the molecular weight of the fatty acid / soap. The method has the advantages of being simple to operate, high in accuracy, convenient, and fast.

Description

Technical Field

[0001] The invention relates to a method for determining the fatty acid / soap content in a fatty acylamino acid / salt product, and belongs to the technical field of quantitative analysis of components of fine chemical products. Background Art

[0002] Fatty acyl amino acid salts are a type of bio-based surfactant synthesized from renewable resources such as fatty acids and amino acids. They have excellent surface and interfacial chemical properties and application performance and are widely used in food, medicine, daily chemicals and other industrial fields. Fatty acyl amino acid salts are usually produced using the Schotten-Baumann condensation process, which uses fatty acyl chloride as an acylating agent and undergoes an amidation reaction with sodium amino acid in an alkaline water / organic solvent system or an alkaline aqueous phase system. Since fatty acyl chloride is very easy to hydrolyze, it is inevitable that a hydrolysis side reaction will occur with water in the system during the reaction to generate fatty acid soaps, thereby affecting the quality of the product.

[0003] The method of synthesizing fatty acyl amino acid salts using fatty acids, fatty acid methyl esters and oils as amidation reaction reagents also inevitably generates fatty acid soaps. In order to reduce the content of fatty acid soaps in fatty acyl amino acid salt products, methods such as increasing the content of organic solvents to reduce the water activity in the system, increasing the content of amino acid sodium to promote the reaction of fatty acyl chlorides and amino acid salts to synthesize fatty acyl amino acid salts, optimizing the reaction temperature and system pH so that the competitive reaction proceeds in the direction of synthesizing fatty acyl amino acid salts, and removing fatty acid soaps in the reaction by extraction, etc. are often used.

[0004] However, no matter whether it is a product directly synthesized by Shotton-Bowman condensation or a product obtained by optimizing reaction or purifying products, the fatty acyl amino acid salt surfactant product contains more or less fatty acid soap. These residual fatty acid soaps greatly affect the product's solubility, surface tension, interfacial tension, efficiency and effectiveness of reducing surface tension, micellization, foaming, wetting, penetration, solubilization, emulsification and adsorption and other colloid and interfacial chemical properties, further affecting the product's appearance and application performance.

[0005] Since the adverse effects of fatty acid soaps on the colloid and interfacial chemical properties and application performance of fatty acyl amino acid surfactant products depend on their content, accurate quantitative analysis of the fatty acid soap content in the product is meaningful for production quality control, technology development, product performance and formulation application of fatty acyl amino acid surfactants.

[0006] At present, the fatty acids or fatty acid soaps in fatty acyl amino acid surfactant products are mainly quantitatively analyzed by gas chromatography and high performance liquid chromatography. However, the difficulty faced by gas chromatography quantitative analysis is the influence of high-boiling point fatty acyl amino acids. In order to reduce the contamination of gas chromatography columns by fatty acyl amino acids, Jiang Zhijie and others first extracted the fatty acids in the acidified fatty acyl amino acid salt products with petroleum ether, and then used gas chromatography to analyze the extracted fatty acids after methyl ester derivatization and infer the soap content therein. However, this method is affected by the extraction rate of fatty acid soap acidification products during the extraction process and the subsequent methyl esterification derivatization efficiency, so the accuracy of the results is questionable.

[0007] The advantage of quantitative analysis by HPLC is that it is not affected by the high boiling point of fatty acyl amino acids, and fatty acid soaps and fatty acyl amino acid salts are easy to separate, and even fatty acyl amino acid salts of different carbon chain lengths can be separated and quantified one by one. However, the signals of fatty acids and their soaps are weak in commonly used ultraviolet detectors. Li Zhongjun et al. used HPLC-UV detection to quantitatively analyze the content of different carbon chain length components in fatty acyl glutamate sodium products, and used sulfuric acid to adjust the pH of the mobile phase to reduce the unfavorable phenomenon of chromatographic peak tailing; these methods either have low detection limits, poor repeatability, or low separation efficiency due to the inability to use gradient elution.

[0008] Fatty acid soap is an anionic surfactant and can be quantitatively analyzed by the association reaction of anionic and cationic surfactants. However, since fatty acyl amino acid salt is also an anionic surfactant, the prior art does not use the method of anionic and cationic surfactant association to quickly and accurately quantitatively analyze the fatty acid soap therein.

[0009] Therefore, how to quickly, simply and accurately quantitatively determine the content of fatty acid soap in fatty acyl amino acid surfactants is an urgent problem to be solved in this field. Summary of the invention

[0010] In order to solve the problem of lack of a fast and simple volumetric method for determining fatty acid soaps in fatty acyl amino acid surfactants, the present invention provides a method for quantitatively determining fatty acid soaps in fatty acyl amino acid salt products. The method is simple, convenient, fast and highly accurate, and can quickly and accurately determine the content of fatty acid soaps in fatty acyl amino acid surfactants. It has broad application significance in production control, technology development, product performance and formula application.

[0011] The invention adopts a cationic surfactant as an associative agent, bromocresol green as an indicator, water, low-carbon alcohol, inorganic salt and chloroalkane as a mixed medium, drops an associative agent solution into a mixed sample containing a fatty acyl amino acid salt product dropwise under a pH value of 10 to 12.5, and vigorously shakes the sample to allow the active substance and the associative compound to be rapidly distributed and balanced in the two phases of the mixed medium until the indicator is completely transferred from the water phase to the chloroalkane phase, records the volume of the consumed associative agent, and infers the fatty acid soap content in the fatty acyl amino acid salt product according to information such as the concentration of the associative agent and the sample dilution ratio.

[0012] The first object of the present invention is to provide a method for determining the fatty acid / soap content in a fatty acylamino acid / salt product, the method comprising:

[0013] Cationic surfactant is used as an associating agent and bromocresol green is used as an indicator; indicator buffer, low-carbon alcohol, inorganic salt and chloroalkane are used as a mixed medium; under the condition of pH 10-12.5, the associating agent is dropped into a mixed solution formed by a fatty acyl amino acid / salt product test solution and the mixed medium; the mixed solution is shaken to quickly distribute and balance until the indicator is completely transferred from the aqueous phase to the chloroalkane phase and turns sky blue, the volume of the consumed associating agent solution is recorded, and the fatty acid / soap content in the fatty acyl amino acid salt product is calculated based on the concentration of the associating agent, the dilution ratio of the sample and the molecular weight of the fatty acid / soap.

[0014] In one embodiment, the general formula of the fatty acyl amino acid / salt is:

[0015]

[0016] is one or more of octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl, linoleoyl, arachidoyl, behenoyl, erucoyl, coconut oil, palm kernel oil, soybean oil, camellia oil, tallow oil, sunflower oil and sesame oil; M+ is H + 、Na + , K + NH4 + NH2 + (CH2CH2OH)2、NH + (CH2CH2OH)3、NH + (CH3)3 or NH + Any one of (CH2CH3)3; n is 1 or 2.

[0017] In one embodiment, the general formula of the fatty acid soap is:

[0018]

[0019] M is any one or more of octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl, linoleoyl, arachidoyl, behenoyl, erucoyl, coconut oil, palm kernel oil, soybean oil, camellia oil, tallow oil, sunflower oil and sesame oil; M + H + 、Na + , K + NH4 + NH2 + (CH2CH2OH)2、NH + (CH2CH2OH)3、NH + (CH3)3 or NH + Any one of (CH2CH3)3.

[0020] In one embodiment, the cationic surfactant includes one or more of Heming 1622, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium bromide, octadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, octadecyldimethylbenzylammonium chloride, and octadecyldimethylbenzylammonium bromide.

[0021] In one embodiment, the low-carbon alcohol includes one or more of methanol, ethanol, n-propanol, and isopropanol.

[0022] In one embodiment, the inorganic salt includes one or both of sodium chloride and sodium sulfate.

[0023] In one embodiment, the chloroalkane includes one or more of chloroform, dichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, and tetrachloroethane.

[0024] In one embodiment, the indicator buffer is a mixed solution of an indicator and a buffer.

[0025] In one embodiment, the buffer is sodium phosphate-sodium dihydrogen phosphate buffer.

[0026] In one embodiment, the mass ratio of the low-carbon alcohol to the inorganic salt in the mixed medium is (1:18) to (1:2).

[0027] In one embodiment, the mass fraction of the low-carbon alcohol is 1.8% to 11% based on the total mass of the mixed medium.

[0028] In one embodiment, the mass fraction of the inorganic salt is 0.7% to 4.4% based on the total mass of the mixed medium.

[0029] In one embodiment, the mass fraction of the chloroalkane is 11% to 32% of the total mass of the mixed medium.

[0030] In one embodiment, the concentration of the association agent solution is 0.5 mmol / L to 20 mmol / L.

[0031] In one embodiment, the volume ratio of the chloroalkane to the indicator buffer is (1:8) to (1:2).

[0032] In one embodiment, the fatty acyl amino acid salt product test solution is prepared by dissolving the fatty acyl amino acid salt solid product or liquid product in water, and then adjusting the pH to 10-12.5 with NaOH solution or KOH solution to make it transparent; and then fixing the volume to obtain the test solution.

[0033] In one embodiment, the process of dropping the associating agent into the mixed solution formed by the fatty acyl amino acid salt product to be tested and the mixed medium is to shake up and down 10 to 30 times after each drop, observe the colors of the water phase and the chloroalkane phase after rapid demulsification, and the titration endpoint is when the color of the indicator in the upper water phase is completely transferred to the lower chloroalkane phase and the chloroalkane phase is sky blue.

[0034] In one embodiment, the specific calculation process of the content of fatty acid soap in the fatty acyl amino acid salt product is as follows:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] Where, C is the concentration of the cationic surfactant solution, mol / L;

[0042] V1 is the volume of indicator buffer consumed in sample titration, mL;

[0043] V2 is the volume of indicator buffer consumed in blank titration, mL;

[0044] V is the volume of the liquid to be tested, mL;

[0045] M is the molecular weight of the fatty acid soap;

[0046] A is the volume dilution multiple of the fatty acylamino acid salt product to be prepared into the test solution;

[0047] w is the weight of the fatty acylamino acid salt product, g;

[0048] v0 is the volume of the fatty acylamino acid salt product weighing wg after constant volume;

[0049] x1 is the molar concentration of fatty acid soap in the test solution, mol / L;

[0050] x2 is the molar concentration of fatty acid soap in the fatty acyl amino acid salt liquid product, mol / L;

[0051] x3 is the amount of fatty acid soap in the fatty acylamino acid salt product per unit mass, mol / g;

[0052] w1 is the mass concentration of fatty acid soap in the test solution, g / L;

[0053] w2 is the mass concentration of fatty acid soap in the fatty acyl amino acid salt liquid product, g / L.

[0054] w3 is the mass percentage of fatty acid soap in the fatty acyl amino acid salt product, %.

[0055] The second object of the present invention is to provide a method for determining the fatty acid / soap content in a fatty acylamino acid / salt product and to apply the method to quantitative analysis of the components of fine chemical products.

[0056] Beneficial effects of the present invention:

[0057] (1) The method for determining the fatty acid / soap content in the fatty acyl amino acid / salt product of the present invention does not rely on expensive instruments such as high performance liquid chromatography and gas chromatograph, and does not require extraction and separation methods to obtain fatty acids / soaps for quantitative analysis; it has the advantages of simple operation, high accuracy, convenience and speed.

[0058] (2) The present invention does not require derivatization treatment of the sample to be tested to reduce the boiling point or increase the ultraviolet absorption or fluorescence absorption;

[0059] (3) The present invention solves the problems of severe emulsification and difficulty in determining the endpoint when quantitatively analyzing fatty acyl amino acid salt products and fatty acid soaps in the products using the existing method of using anion / cation association and its distribution equilibrium in water-soluble and water-insoluble phases. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is a diagram of the stratification and color development phenomenon of the mixed medium at the titration endpoint of Example 3 of the present invention;

[0061] Figure 2 This is the HPLC chromatogram of sodium lauroyl glutamate product A of Example 3 of the present invention; the substance corresponding to the chromatographic peak at a retention time of 8.56 min is lauroyl glutamate, and the substance corresponding to the chromatographic peak at 18.97 min is lauric acid. DETAILED DESCRIPTION

[0062] The present invention is further described below in conjunction with specific examples, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0063] Preparation of indicator solution: Accurately weigh 0.060 g of bromocresol green, dilute to 1000 mL with ultrapure water, shake well and let stand for 12 h to obtain bromocresol green mother solution I.

[0064] 1. Preparation of indicator phosphate buffer I: Accurately weigh 10.70g Na2HPO4·12H2O, 0.06g Na3PO4·12H2O, 8mL bromocresol green mother solution I and 100mL water in a 500mL beaker, stir to dissolve and transfer to a 500mL volumetric flask; wash the beaker several times with an appropriate amount of ultrapure water, and transfer all the washings to the volumetric flask; then make up to volume with ultrapure water to obtain 0.06mol / L pH 10 indicator phosphate buffer I.

[0065] 2. Preparation of indicator phosphate buffer II: Accurately weigh 9.43g Na2HPO4·12H2O, 1.39g Na3PO4·12H2O, 8mL bromocresol green mother solution I and 100mL water in a 500mL beaker, stir to dissolve and transfer to a 500mL volumetric flask; wash the beaker several times with an appropriate amount of ultrapure water, and transfer all the washings to the volumetric flask; then make up to volume with ultrapure water to obtain 0.06mol / L pH 11.5 indicator phosphate buffer II.

[0066] 3. Preparation of indicator phosphate buffer III: Accurately weigh 7.46g Na2HPO4·12H2O, 3.48g Na3PO4·12H2O, 8mL bromocresol green mother solution I and 100mL water into a 500mL beaker, stir to dissolve and transfer to a 500mL volumetric flask; wash the beaker several times with an appropriate amount of ultrapure water, and transfer all the washings to the volumetric flask; then make up to volume with ultrapure water to obtain 0.06mol / L pH 12 indicator phosphate buffer III.

[0067] 4. Preparation of indicator phosphate buffer IV: Accurately weigh 4.49 g Na2HPO4·12H2O, 6.64 g Na3PO4·12H2O, 8 mL bromocresol green mother solution I and 100 mL water into a 500 mL beaker, stir to dissolve and transfer to a 500 mL volumetric flask; wash the beaker several times with an appropriate amount of ultrapure water, and transfer all the washings to the volumetric flask; then make up to volume with ultrapure water to obtain 0.06 mol / L indicator phosphate buffer IV with a pH of 12.5.

[0068] Example 1

[0069] Determination of lauric acid content in lauroyl glutamate.

[0070] (1) Sample determination: Accurately weigh 0.3291 g of lauroyl glutamic acid and 0.0523 g of lauric acid, add 100 mL of ultrapure water and an appropriate amount of 30% KOH solution, adjust the pH to 12.0, transfer to a 250 mL volumetric flask and dilute to volume with ultrapure water to obtain the test solution.

[0071] Pipette 25.00mL of the test solution into a 100mL stoppered measuring cylinder, then add 20mL of indicator phosphate buffer III, 10mL of chloroform, 0.9g of Na2SO4 and 2.2g of ethanol, shake well and titrate with 2mmol / L Heming 1622 standard solution. Add about 2mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 42min.

[0072] (2) Blank test: Replace the above 25.00 mL of the test solution with 25.00 mL of ultrapure water for a blank test. That is, transfer 25.00 mL of ultrapure water into a 100 mL stoppered measuring cylinder, add 20 mL of indicator phosphate buffer III, 10 mL of chloroform, 0.9 g of Na2SO4 and 2.2 g of ethanol, shake well and titrate dropwise with 2 mmol / L of Heming 1622 standard solution. Shake vigorously 30 times after each drop, and take care to release air in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, the blank test titration endpoint is reached.

[0073] After deducting the volume of the blank consumed associating agent solution, the volume of the standard solution of hydrating 1622 consumed in the titration in the above sample is 13.29 mL. Combined with the concentration of the hydrating 1622 associating agent and the dilution ratio of the sample, the ratio of the amount of hydrating 1622 consumed in the titration to the amount of lauric acid in the system is 1.018:1, indicating that hydrating 1622 does not associate with lauroyl glutamate. Using this method, the mass fraction of lauric acid in the mixture can be measured to be 13.96%, and the mass fraction of lauric acid in the mixture calculated from the actual weighing value is 13.71%.

[0074] It can be seen that the value determined by the method of the present invention is comparable to the weighed value data and is within the error range, indicating that the method can be used for the quantitative determination of the lauric acid content in lauroyl glutamate.

[0075] Example 2

[0076] Determination of disodium palmitoyl aspartate content.

[0077] (1) Sample determination: Accurately weigh 0.3616 g of disodium palmitoyl aspartate, add 100 mL of deionized water, and then adjust the pH to 12.5 with 1 mol / L NaOH solution; transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0078] In a 100-mL stoppered measuring cylinder, 15.00 mL of disodium palmitoyl aspartate test solution, 15 mL of indicator phosphate buffer IV, 10 mL of dichloromethane, 0.9 g of NaCl and 1.1 g of ethanol were added respectively. After shaking, 4 mmol / L hamming 1622 associating agent solution was added dropwise. After each addition, the mixture was vigorously shaken 30 times. Note that air was released in the middle. After stratification, the color of the dichloromethane layer was observed. The titration endpoint was reached when the color of the indicator in the upper aqueous layer was completely transferred to the lower layer and turned sky blue. The total titration time was 63 min, and the volume of hamming 1622 associating agent solution consumed in the titration was 0.26 mL.

[0079] (2) Blank test: Replace the above 15.00 mL of the test solution with 15.00 mL of ultrapure water and conduct a blank test.

[0080] The titration of disodium palmitoyl aspartate test solution consumed 0.26 mL of hamming 1622 associating agent solution, and the titration of the blank consumed 0.25 mL of hamming 1622 associating agent solution. The volume of hamming 1622 associating agent solution consumed by the titration of disodium palmitoyl aspartate test solution was equivalent to that of the titration of the blank, indicating that disodium palmitoyl aspartate did not associate with hamming 1622 in the mixed medium.

[0081] Example 3

[0082] Determination of potassium myristic acid content.

[0083] (1) Sample determination: Accurately weigh 0.0131 g potassium myristic acid, add 20 mL deionized water, and then adjust the pH to 12.0 with 1 mol / L KOH solution; transfer to a 100 mL volumetric flask and dilute to obtain the test solution.

[0084] In a 100-mL stoppered measuring cylinder, add 10.00 mL of potassium myristic acid test solution, 20 mL of indicator phosphate buffer III, 15 mL of dichloroethane, 2.0 g of NaCl and 1.1 g of n-propanol. After shaking, add 0.5 mmol / L hexadecyldimethylbenzylammonium bromide associating agent solution drop by drop. Shake vigorously 30 times after each addition. After stratification, observe the color of the dichloroethane layer. The titration endpoint is when the color of the indicator in the upper aqueous layer is completely transferred to the lower layer and turns sky blue. The total titration time is 43 min.

[0085] (2) Blank test: Replace the above 10.00 mL of the test solution with 10.00 mL of ultrapure water and conduct a blank test.

[0086] The volume of hexadecyldimethylbenzylammonium bromide associating agent solution consumed in the titration is 10.31 mL. After deducting the volume of the blank associating agent solution consumed, combined with the concentration of the associating agent solution and the dilution ratio of potassium myristate, it can be calculated that the ratio of the amount of hexadecyldimethylbenzylammonium bromide consumed in the titration to the amount of potassium myristate is 1.049:1, that is, the two are associated in a nearly stoichiometric ratio.

[0087] Example 4

[0088] Determination of sodium laurate content in disodium lauroyl glutamate.

[0089] (1) Sample determination: Accurately weigh 0.3636 g of disodium lauroyl glutamate and 0.2215 g of sodium laurate, add 100 mL of deionized water and an appropriate amount of 30% NaOH solution until the system pH is 12.5, transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0090] Pipette 25.00mL of the test solution into a 100mL stoppered measuring cylinder, add 5mL of indicator phosphate buffer IV, 20mL of trichloroethane, 2.25g of NaCl and 1.1g of isopropanol, shake well and titrate with 20mmol / L hamming 1622 solution; add 2mL each time at the beginning, reduce the amount of each drop when the stratification speed becomes significantly faster, shake vigorously 30 times after each drop, pay attention to venting in the middle, observe the color of the lower trichloroethane layer after stratification, and the end point is when the color of the indicator is completely transferred from the upper layer to the lower layer and turns sky blue. The total titration time is 49min.

[0091] (2) Blank test: Replace the above 25.00 mL of the test solution with 25.00 mL of ultrapure water and conduct a blank test.

[0092] The volume of the associative agent solution of 1622 consumed in the titration is 4.99 mL. After deducting the volume of the associative agent solution consumed in the blank, combined with the concentration of the associative agent solution and the dilution ratio of the sample, it can be calculated that the ratio of the amount of 1622 consumed in the titration to the amount of sodium laurate in the system is 1.002:1.

[0093] The results of Example 1 show that the Heming 1622 associating agent does not associate with disodium lauroyl glutamate in the mixed medium of the present invention; the results of Example 4 further illustrate that the Heming 1622 associating agent does not associate with disodium lauroyl glutamate, and the consumed associating agent associates with the sodium laurate therein in a stoichiometric ratio, so this method can be used to quantitatively analyze the sodium laurate content in the disodium lauroyl glutamate product.

[0094] Example 5

[0095] Determination of potassium stearate content in dipotassium stearoyl aspartate.

[0096] (1) Sample determination: Accurately weigh 0.4660 g of dipotassium stearoyl aspartate and 0.2437 g of potassium stearate, add 100 mL of deionized water and an appropriate amount of 15% KOH solution until the pH of the system is 11.5, transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0097] Pipette 25.00mL of the test solution into a 100mL stoppered measuring cylinder, add 10mL of indicator phosphate buffer II and 15mL of tetrachloroethane, 0.5g of Na2SO4 and 2.2g of methanol, shake well and titrate with 3mmol / L hydrazine 1622 associating agent solution; add 2mL each time at the beginning, and reduce the amount of each drop when the stratification speed becomes significantly faster. Shake vigorously 30 times after each drop, and pay attention to venting in the middle. After stratification, observe the color of the lower tetrachloroethane layer. The end point is when the color of the indicator is completely transferred from the upper layer to the lower layer and turns sky blue. The total titration time is 57min.

[0098] (2) Blank test: Replace the above 15.00 mL of the test solution with 15.00 mL of ultrapure water and conduct a blank test.

[0099] The volume of the associative agent solution consumed in the titration is 25.43 mL. After deducting the volume of the associative agent solution consumed in the blank, combined with the concentration of the associative agent 1622 and the dilution ratio of the sample, it can be calculated that the ratio of the amount of hydrazine 1622 consumed in the titration to the amount of potassium stearate in the system is 1.010:1.

[0100] The results of Example 2 show that the Hemming 1622 associating agent does not associate with disodium palmitoyl aspartate in the mixed medium of the present invention, and the results of Example 5 further show that the Hemming 1622 associating agent does not associate with dipotassium stearoyl aspartate, and the consumed associating agent associates with the potassium stearate therein in a stoichiometric ratio. Therefore, this method can be used to quantitatively analyze the content of potassium stearate in dipotassium stearoyl aspartate.

[0101] Example 6

[0102] Determination of disodium lauroyl glutamate content.

[0103] (1) Sample determination: Accurately weigh 0.3766 g of disodium lauroyl glutamate, add 100 mL of deionized water, and then adjust the pH to 11.5 with 1 mol / L NaOH solution; transfer to a 250 mL volumetric flask and make up to volume to obtain the test solution.

[0104] In a 100mL stoppered measuring cylinder, add 25.00mL of disodium lauroyl glutamate test solution, 15mL of indicator phosphate buffer solution II, 10mL of chloroform, 0.5g of NaCl and 1.1g of methanol. After shaking, add 4mmol / L hydrazine 1622 associating agent solution drop by drop. Shake vigorously 30 times after each addition. Pay attention to degassing in the middle. After stratification, observe the color of the chloroform layer. When the color of the indicator in the upper water layer is completely transferred to the lower chloroform layer and turns sky blue, the titration end point is reached. The total titration time is 50min, and the titration consumes 0.23mL of hydrazine 1622 associating agent solution.

[0105] (2) Blank test: Replace the above 25.00 mL of the test solution with 25.00 mL of ultrapure water and conduct a blank test.

[0106] The titration of disodium lauroyl glutamate test solution consumed 0.23 mL of hydrating agent solution 1622, and the titration of the blank consumed 0.25 mL of hydrating agent solution 1622. The volume of hydrating agent solution consumed by the titration of disodium lauroyl glutamate test solution was equivalent to that of the titration of the blank, indicating that disodium lauroyl glutamate did not associate with hydrating agent 1622 in the mixed medium.

[0107] Example 7

[0108] Determination of erucic acid content in erucyl aspartic acid.

[0109] (1) Sample determination: Accurately weigh 0.4253 g of erucyl aspartic acid and 0.0872 g of erucic acid, add 100 mL of ultrapure water and an appropriate amount of 30% NaOH solution to adjust the pH to 12.0, transfer to a 250 mL volumetric flask and make up to volume with ultrapure water.

[0110] Pipette 25.00mL of the test solution into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer III, 5mL of chloroform, 2.0g of Na2SO4 and 2.2g of methanol. Shake well and titrate with 1mmol / L of Hemingway 1622 standard solution. Add about 2mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point.

[0111] (2) Blank test: Replace the above 25.00 mL of the test solution with 25.00 mL of ultrapure water and conduct a blank test.

[0112] After deducting the volume of the blank consumed associating agent solution, the volume of the standard solution of Heming 1622 consumed in the titration in the above sample is 26.01 mL. Combined with the concentration of the Heming 1622 associating agent and the dilution ratio of the sample, the ratio of the amount of Heming 1622 consumed in the titration to the amount of erucic acid in the system is 1.00:1.00, indicating that Heming 1622 does not associate with erucyl aspartic acid. This method can be used to measure the content of erucic acid in erucyl aspartic acid.

[0113] Example 8

[0114] Determination of sodium laurate content in sodium lauroyl glutamate products.

[0115] (1) Sample determination: Accurately weigh 8.7470 g of sodium lauroyl glutamate liquid product A, add 250 mL of deionized water, adjust the pH to 11.5 with 15% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution A2.

[0116] Pipette 25.00mL of the test solution A2 into a 100mL stoppered measuring cylinder, then add 10mL of indicator phosphate buffer II, 10mL of chloroform, 2.25g of Na2SO4 and 2.2g of n-propanol, shake well and titrate with 2mmol / L of Heming 1622 associating agent standard solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The titration time is 67min.

[0117] (2) Blank test: Replace the above 25.00 mL of the test solution with 25.00 mL of ultrapure water and perform a blank test.

[0118] The titration was repeated 5 times in total, and the volume of the blank consumed associative agent solution was deducted. According to the volume of the associative agent consumed in the titration, combined with the concentration of the associative agent 1622, the dilution ratio of the sodium lauroyl glutamate liquid product A and the molecular weight of sodium laurate, the sodium laurate contents calculated 5 times were 2.71%, 2.73%, 2.76%, 2.67% and 2.72%, respectively, indicating that the method of the present invention has good repeatability. The mass percentage of sodium laurate in product A was calculated to be 2.72%.

[0119] Result verification: Weigh 0.0523g of sodium lauroyl glutamate liquid product A, dilute to 10mL with chromatographic grade methanol to obtain test solution A3, and analyze by high performance liquid chromatography; chromatographic conditions: injection 20μL, C18 chromatographic column, 5% formic acid methanol solution mobile phase, isocratic elution, differential refractive index detector; measure the lauric acid content in the injection;

[0120] Combined with the dilution ratio of sample A and the molecular weights of sodium laurate and disodium lauroyl glutamate, the mass percentage of sodium laurate in the sodium lauroyl glutamate liquid product A is calculated to be 2.69%.

[0121] The above results show that the content of sodium laurate in product A measured by high performance liquid chromatography is consistent with the result measured in the present invention, indicating that the method for quantitative analysis of fatty acid soap in fatty acyl amino acid salt surfactant of the present invention can accurately determine the content of fatty acid soap.

[0122] Example 9

[0123] Determination of ammonium laurate content in ammonium lauroyl glutamate products.

[0124] (1) Sample determination: Accurately weigh 0.7973 g of ammonium lauroyl glutamate liquid product B, add 100 mL of deionized water, adjust the pH to 10.0 with 15% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution B2.

[0125] Pipette 25.00mL of the test solution into a 100mL stoppered measuring cylinder, then add 20mL of indicator phosphate buffer I, 15mL of chloroform, 0.5g of NaCl and 3.3g of methanol. Shake well and titrate with 2mmol / L of Heming 1622 associating agent solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 56min.

[0126] (2) Blank test: Replace the above 25.00 mL of the test solution B2 with 25.00 mL of ultrapure water for a blank test. Repeat the titration three times, deduct the volume of the associative agent solution consumed in the blank, and the average volume of the associative agent solution consumed by the titration is 4.57 mL. Combined with the concentration of the associative agent 1622, the dilution ratio of the ammonium lauroyl glutamate liquid product and the molecular weight of ammonium laurate, the mass percentage of ammonium laurate in product B is calculated to be 2.55%.

[0127] Example 10

[0128] Determination of lauric acid monoethanolamine salt content in lauroyl glutamic acid monoethanolamine salt products.

[0129] (1) Sample determination: Accurately weigh 0.3624 g of lauroyl glutamic acid monoethanolamine salt powder product C, add 100 mL of deionized water and adjust the pH to 12.0 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute to volume with deionized water to obtain the test solution C2.

[0130] Pipette 25.00mL of the test solution C2 into a 100mL stoppered measuring cylinder, then add 5mL of indicator phosphate buffer III, 20mL of chloroform, 0.9g of NaCl and 3.3g of ethanol. Shake well and titrate with 2mmol / L hexadecyldimethylbenzylammonium bromide associating agent solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 34min.

[0131] (2) Blank test: Replace the above 25.00 mL of the test solution C2 with 25.00 mL of ultrapure water and conduct a blank test.

[0132] The titration was repeated three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of the hexadecyldimethylbenzylammonium bromide associative agent solution consumed in the titration was 1.59 mL. Combined with the concentration of the hexadecyldimethylbenzylammonium bromide associative agent, the dilution ratio of the lauroyl glutamate monoethanolamine salt powdered product C and the molecular weight of lauric acid monoethanolamine salt, the mass percentage of lauric acid monoethanolamine salt in product C was calculated to be 0.59%.

[0133] Embodiment 11

[0134] Determination of the content of trimethylamine octanoate in trimethylamine octanoylglutamate products.

[0135] (1) Sample determination: Weigh 1.0899 g of octanoyl glutamic acid trimethylamine salt liquid product D, add 100 mL of deionized water and adjust the pH to 12.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution D2.

[0136] Accurately transfer 25.00mL of the test solution into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer IV, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol. Shake well and titrate with 2mmol / L dodecyldimethylbenzylammonium bromide associating agent solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 40min.

[0137] (2) Blank test: Replace the above 25.00 mL of the test solution D2 with 25.00 mL of ultrapure water and conduct a blank test.

[0138] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of dodecyldimethylbenzylammonium bromide associative agent solution consumed in the titration was 2.06 mL. Based on the concentration of the associative agent, the dilution ratio of the octanoylglutamate trimethylamine liquid product D and the molecular weight of octanoic acid trimethylamine, the mass percentage of octanoic acid trimethylamine salt in product D was calculated to be 0.78%.

[0139] Example 12

[0140] Determination of Sodium Nonanoate Content in Sodium Nonanoyl Glutamate Products.

[0141] (1) Sample determination: Accurately weigh 0.9124 g of solid product E of sodium nonanoyl glutamate, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution E2.

[0142] Pipette 25.00mL of the test solution E2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L tetradecyldimethylbenzylammonium bromide associating agent solution. Add about 1mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 67min.

[0143] (2) Blank test: Replace the above 25.00 mL of the test solution E2 with 25.00 mL of ultrapure water and conduct a blank test.

[0144] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of tetradecyldimethylbenzylammonium bromide associative agent solution consumed in the titration was 2.47 mL. Combined with the concentration of the associative agent, the dilution ratio of the sodium nonanoyl glutamate liquid product E and the molecular weight of sodium nonanoate, the mass content of sodium nonanoate in product E was calculated to be 1.95%.

[0145] Embodiment 13

[0146] Determination of Sodium Decanoate Content in Sodium Decanoyl Glutamate Products.

[0147] (1) Sample determination: Accurately weigh 0.8544 g of sodium decanoyl glutamate liquid product F, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution F2.

[0148] Pipette 25.00mL of the test solution F2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L octadecyldimethylbenzylammonium bromide associating agent solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each drop. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 55min.

[0149] (2) Blank test: Replace the above 25.00 mL of the test solution F2 with 25.00 mL of ultrapure water and conduct a blank test.

[0150] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of the octadecyldimethylbenzylammonium bromide associative agent solution consumed in the titration was 1.95 mL. Based on the concentration of the associative agent, the dilution ratio of the sodium decanoyl glutamate liquid product F and the molecular weight of sodium decanoate, the mass percentage of sodium decanoate in product F was calculated to be 0.88%.

[0151] Embodiment 14

[0152] Determination of sodium linoleate content in sodium linoleoyl glutamate products.

[0153] (1) Sample determination: Accurately weigh 0.9080 g of the solid product G of sodium linoleyl glutamate, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution G2.

[0154] Pipette 25.00mL of the test solution G2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L dodecyldimethylbenzylammonium chloride associating agent solution. Add about 1mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 43min.

[0155] (2) Blank test: Replace the above 25.00 mL of the test solution G2 with 25.00 mL of ultrapure water and conduct a blank test.

[0156] The titration was performed three times in total, and the volume of the blank consumed associative agent solution was deducted. The average volume of dodecyldimethylbenzylammonium chloride associative agent solution consumed in the titration was 1.79 mL. Combined with the concentration of the associative agent, the dilution ratio of the sodium linoleoyl glutamate liquid product G and the molecular weight of sodium linoleate, the mass percentage of sodium linoleate in product G was calculated to be 1.19%.

[0157] Embodiment 15

[0158] Determination of Sodium Arachidate Content in Sodium Arachidonyl Glutamate Products.

[0159] (1) Sample determination: Accurately weigh 0.8268 g of sodium arachidonyl glutamate liquid product H, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute to volume with deionized water to obtain the test solution H2.

[0160] Pipette 25.00mL of the test liquid H2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L tetradecyldimethylbenzylammonium chloride associating agent solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each drop. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 35min.

[0161] (2) Blank test: Replace the above 25.00 mL of the test solution H2 with 25.00 mL of ultrapure water and conduct a blank test.

[0162] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of tetradecyldimethylbenzylammonium chloride associative agent solution consumed in the titration was 2.42 mL. Based on the concentration of the associative agent, the dilution ratio of sodium arachidonate liquid product H and the molecular weight of sodium arachidonate, the mass percentage of sodium arachidonate in product H was calculated to be 0.49%.

[0163] Example 16

[0164] Determination of sodium behenate content in sodium behenyl glutamate products.

[0165] (1) Sample determination: Accurately weigh 0.9913 g of sodium behenyl glutamate liquid product I, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute to volume with deionized water to obtain the test solution I2.

[0166] Pipette 25.00mL of the test solution I2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L hexadecyldimethylbenzylammonium chloride associating agent solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each drop. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 45min.

[0167] (2) Blank test: Replace the above 25.00 mL of the test solution I2 with 25.00 mL of ultrapure water for a blank test. Titrate three times in total, deduct the volume of the associative agent solution consumed in the blank, and the average volume of the hexadecyl dimethyl benzyl ammonium chloride associative agent solution consumed in the titration is 3.36 mL. Combined with the concentration of the associative agent, the dilution ratio of the sodium behenyl glutamate liquid product I and the molecular weight of sodium behenate, the mass percentage of sodium behenate in the product I is calculated to be 1.23%.

[0168] Embodiment 17

[0169] Determination of Coconut Oil Diethanolamine Salt Content in Cocoyl Glutamic Acid Diethanolamine Salt Products:

[0170] (1) Sample determination: Accurately weigh 0.6129 g of cocoyl glutamic acid diethanolamine salt liquid product J, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution J2.

[0171] Pipette 25.00mL of the test solution J2 into a 100mL stoppered measuring cylinder, then add 10mL of indicator phosphate buffer II, 15mL of chloroform, 2.0g of NaCl and 3.3g of n-propanol, shake well and titrate with 2mmol / L octadecyldimethylbenzylammonium chloride associating agent solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each drop. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 49min.

[0172] (2) Blank test: Replace the above 25.00 mL of the test solution J2 with 25.00 mL of ultrapure water for a blank test. Titrate three times in total, deduct the volume of the associative agent solution consumed in the blank, and the average volume of the associative agent solution consumed by titration is 2.45 mL. Combined with the concentration of the associative agent, the dilution ratio of the coconut oil acyl glutamate diethanolamine salt liquid product J and the molecular weight of coconut oil diethanolamine salt, the mass percentage of coconut oil diethanolamine salt in product J is calculated to be 1.79%

[0173] Embodiment 18

[0174] Determination of palm kernel oleic acid diethylamine salt content in palm kernel oleoyl glutamate diethylamine salt product.

[0175] (1) Sample determination: Accurately weigh 0.9324 g of palm kernel oleoyl glutamic acid diethylamine salt liquid product K, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute to volume with deionized water to obtain the test solution K2.

[0176] Pipette 25.00mL of the test solution K2 into a 100mL stoppered measuring cylinder, then add 20mL of indicator phosphate buffer II, 10mL of chloroform, 2.25g of Na2SO4 and 3.3g of isopropanol, shake well and titrate with 2mmol / L dodecyltrimethylammonium chloride associating agent solution. Add about 1mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 50min.

[0177] (2) Blank test: Replace the above 25.00 mL of the test solution K2 with 25.00 mL of ultrapure water for a blank test. Titrate three times in total, deduct the volume of the associative agent solution consumed in the blank, and the average volume of the associative agent solution consumed in the titration is 1.28 mL. Combined with the concentration of the associative agent, the dilution ratio of the palm kernel oleoyl glutamic acid diethylamine salt liquid product K and the molecular weight of the palm kernel oleic acid diethylamine salt, the mass percentage of the palm kernel oleic acid diethylamine salt in the product K is calculated to be 0.45%.

[0178] Embodiment 19

[0179] Determination of soybean oleic acid triethanolamine salt content in soybean oleyl glutamic acid triethanolamine salt products.

[0180] (1) Sample determination: Accurately weigh 0.7653 g of soybean oil acyl glutamic acid triethanolamine salt liquid product L, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute to volume with deionized water to obtain the test solution L2.

[0181] Pipette 25.00mL of the test solution L2 into a 100mL stoppered measuring cylinder, then add 5mL of indicator phosphate buffer II, 5mL of chloroform, 0.5g of Na2SO4 and 4.4g of methanol. Shake well and titrate with 2mmol / L tetradecyltrimethylammonium chloride associating agent solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 33min.

[0182] (2) Blank test: Replace the above 25.00 mL of the test solution L2 with 25.00 mL of ultrapure water and conduct a blank test.

[0183] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of tetradecyltrimethylammonium chloride associative agent solution consumed in the titration was 1.02 mL. Based on the concentration of the associative agent, the dilution ratio of soybean oleoyl glutamate triethanolamine salt liquid product L and the molecular weight of soybean oleic acid triethanolamine salt, the mass percentage of soybean oleic acid triethanolamine salt in product L was calculated to be 0.96%.

[0184] Embodiment 20

[0185] Determination of soybean oleic acid triethylamine salt content in soybean oleyl glutamic acid triethylamine salt products.

[0186] (1) Sample determination: Weigh 0.8897 g of soybean oleoyl glutamic acid triethylamine salt liquid product M, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution M2.

[0187] Accurately transfer 25.00mL of the test solution M2 into a 100mL stoppered measuring cylinder, and then add 10mL of indicator phosphate buffer II, 10mL of chloroform, 0.9g of Na2SO4 and 4.4g of ethanol. Shake well and titrate with 2mmol / L hexadecyltrimethylammonium chloride associating agent solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 40min.

[0188] (2) Blank test: Replace the above 25.00 mL of the test solution M2 with 25.00 mL of ultrapure water for a blank test. Titrate three times in total, deduct the volume of the associative agent solution consumed in the blank, and the average volume of the hexadecyltrimethylammonium chloride associative agent solution consumed in the titration is 2.44 mL. Combined with the concentration of the associative agent, the dilution ratio of the soybean oleoyl glutamic acid triethylamine salt liquid product M and the molecular weight of soybean oleic acid triethylamine salt, the mass percentage of soybean oleic acid triethylamine salt in the product M is calculated to be 1.66%.

[0189] Embodiment 21

[0190] Determination of sodium camellia acid content in camellia acylglutamate products.

[0191] (1) Sample determination: Accurately weigh 0.6693 g of camellia acyl glutamate sodium liquid product N, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution N2.

[0192] Pipette 25.00mL of the test solution N2 into a 100mL stoppered measuring cylinder, then add 20mL of indicator phosphate buffer II, 15mL of chloroform, 2.0g of Na2SO4 and 4.4g of n-propanol, shake well and titrate with 2mmol / L octadecyltrimethylammonium chloride associating agent solution. Add about 1mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper layer indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 66min.

[0193] (2) Blank test: Replace the above 25.00 mL of the test liquid N2 with 25.00 mL of ultrapure water and conduct a blank test.

[0194] The titration was performed three times in total, and the average volume of octadecyltrimethylammonium chloride associative agent solution consumed in the titration was 3.02 mL. Based on the concentration of the associative agent, the dilution ratio of the sodium camellia acyl glutamate liquid product N and the molecular weight of sodium camellia acid, the mass content of sodium camellia acid in product N was calculated to be 0.0451 mmol / g.

[0195] Embodiment 22

[0196] Determination of sodium tallowate content in sodium tallowyl glutamate products.

[0197] (1) Sample determination: Accurately weigh 0.8650 g of sodium tallowyl glutamate liquid product O, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution O2.

[0198] Pipette 25.00mL of the test solution O2 into a 100mL stoppered measuring cylinder, then add 5mL of indicator phosphate buffer II, 10mL of chloroform, 2.25g of Na2SO4 and 4.4g of isopropanol, shake well and titrate with 2mmol / L dodecyltrimethylammonium bromide associating agent solution. Add about 1mL each time at the beginning, and reduce the amount of addition when the stratification speed becomes obviously faster. Shake vigorously 30 times after each addition, and pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 43min.

[0199] (2) Blank test: Replace the above 25.00 mL of the test liquid O2 with 25.00 mL of ultrapure water and conduct a blank test.

[0200] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of dodecyltrimethylammonium bromide associative agent solution consumed in the titration was 1.84 mL. Based on the concentration of the associative agent, the dilution ratio of the sodium tallowoyl glutamate liquid product O and the molecular weight of sodium tallowate, the mass content of sodium tallowate in product O was calculated to be 0.0213 mmol / g.

[0201] Embodiment 23

[0202] Determination of sodium sunflower seed acid content in sodium sunflower acylglutamate products.

[0203] (1) Sample determination: Accurately weigh 0.5656 g of sodium sunflower acyl glutamate liquid product P, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution P2.

[0204] Pipette 25.00mL of the test solution P2 into a 100mL stoppered measuring cylinder, then add 10mL of indicator phosphate buffer II, 15mL of chloroform, 0.5g of NaCl, 0.5g of Na2SO4 and 4.4g of methanol. Shake well and titrate with 2mmol / L octadecyltrimethylammonium bromide standard solution. Add about 1mL each time at the beginning. When the stratification speed becomes obviously faster, reduce the amount of addition. Shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 77min.

[0205] (2) Blank test: Replace the above 25.00 mL of the test solution P2 with 25.00 mL of ultrapure water and conduct a blank test.

[0206] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of the octadecyltrimethylammonium bromide standard solution consumed in the titration was 4.23 mL. Combined with the concentration of the titrant, the dilution ratio of the sodium sunflower acyl glutamate liquid product P and the molecular weight of sodium sunflower acid, the mass content of sodium sunflower acid in the product P was calculated to be 0.0748 mmol / g.

[0207] Embodiment 24

[0208] Determination of sodium sesame acid content in sodium sesame acid acyl glutamate products.

[0209] (1) Sample determination: Weigh 0.8167 g of sesame oil sodium glutamate liquid product Q, add 100 mL of deionized water and adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution Q2.

[0210] Accurately transfer 25.00mL of the test solution Q2 into a 100mL stoppered measuring cylinder, and then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.0g of NaCl, 1.0g of Na2SO4 and 2.2g of ethanol. Shake well and titrate with 2mmol / L tetradecyltrimethylammonium bromide standard solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 35min.

[0211] (2) Blank test: Replace the above 25.00 mL of the test solution Q2 with 25.00 mL of ultrapure water and conduct a blank test.

[0212] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of tetradecyltrimethylammonium bromide standard solution consumed in the titration was 2.76 mL. Combined with the concentration of the titrant, the dilution ratio of the sodium sesame oil acyl glutamate liquid product Q and the molecular weight of sodium sesame oil, the mass content of sodium sesame oil in product Q was calculated to be 0.0338 mmol / g.

[0213] Embodiment 25

[0214] Determination of sodium oleate content in sodium oleoyl glutamate products.

[0215] (1) Sample determination: Accurately weigh 0.8167 g of sodium oleoyl glutamate liquid product R, add 100 mL of deionized water, adjust the pH to 11.5 with 17% NaOH solution, transfer to a 250 mL volumetric flask and dilute with deionized water to obtain the test solution R2.

[0216] Pipette 25.00mL of the test solution R2 into a 100mL stoppered measuring cylinder, then add 15mL of indicator phosphate buffer II, 10mL of chloroform, 1.7g of NaCl, 0.5g of Na2SO4 and 3.3g of n-propanol, shake well and titrate with 2mmol / L hexadecyltrimethylammonium bromide standard solution. At the beginning, add about 1mL each time. When the stratification speed becomes obviously faster, reduce the amount of addition. During this period, shake vigorously 30 times after each addition. Pay attention to venting in the middle. After complete stratification, observe the color of the chloroform layer. When the upper indicator is completely transferred to the lower layer and turns sky blue, it is the titration end point. The total titration time is 48min.

[0217] (2) Blank test: Replace the above 25.00 mL of the test solution R2 with 25.00 mL of ultrapure water and conduct a blank test.

[0218] The titration was performed three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of the hexadecyltrimethylammonium bromide standard solution consumed in the titration was 2.76 mL. Combining the concentration of the associative agent, the dilution ratio of the sodium oleoyl glutamate liquid product R and the molecular weight of sodium oleate, the mass percentage of sodium oleate in the product R was calculated to be 1.03%.

[0219] Embodiment 26

[0220] Spiked recovery test: Determination of spiked recovery by adding sodium laurate to sodium lauroyl glutamate liquid sample A. 0.1074 g, 0.2009 g, 0.5109 g, 1.0103 g, 1.6242 g and 1.9589 g of sodium laurate were added to 6 1 g liquid samples A, respectively, deionized water and 30% sodium hydroxide solution were added to pH 10-12.5, transferred to a 250 mL volumetric flask and fixed to volume with deionized water; the sodium laurate therein was determined by the method of Example 8, and the calculated recoveries after deducting the sodium laurate in product A were 99.08%, 98.36%, 99.71%, 98.91%, 98.50% and 99.61%, respectively; the recovery rates met the analytical detection standards and could be used for quantitative detection and analysis.

[0221] Comparative Example 1

[0222] The content of sodium lauroyl glutamate was determined in the mixed medium without adding low-carbon alcohol.

[0223] (1) Sample determination: Accurately weigh 0.4574 g of disodium lauroyl glutamate, add 100 mL of deionized water, and then adjust the pH to 11.5 with NaOH; transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0224] In a 100mL stoppered measuring cylinder, add 25.00mL of disodium lauroyl glutamate test solution, 15mL of indicator phosphate buffer I, 10mL of chloroform, and 1.0g of NaCl, shake well, and then drop by drop 4mmol / L of Heming 1622 associating agent solution. Shake vigorously 30 times after each addition, and pay attention to degassing in the middle. After stratification, observe the color of the chloroform layer. The titration endpoint is when the color of the indicator in the upper water layer is completely transferred to the lower layer and turns sky blue.

[0225] (2) Blank test: replace the above 25.00 mL of disodium lauroyl glutamate test solution with 25.00 mL of ultrapure water, and the other conditions are the same as above.

[0226] Due to the slow stratification speed, it took about 10 hours to titrate until the color of the upper indicator was completely transferred to the lower layer. After deducting the volume of the blank consumed associative agent solution, 17.35 mL of the hydrazine 1622 associative agent solution was consumed in the titration. The above results showed that the molar ratio of the consumed hydrazine 1622 associative agent to disodium lauroyl glutamate was 0.5667:1, indicating that disodium lauroyl glutamate and hydrazine 1622 could associate in the mixed medium, and in a non-stoichiometric ratio, indicating that the mixed medium could not be used to determine the soap in fatty acyl amino acid type surfactants, nor could it accurately determine the total content of fatty acyl amino acid salts and fatty acid soaps in the system.

[0227] Comparative Example 2

[0228] Determination of sodium laurate content in sodium lauroyl glutamate in a mixed medium without adding inorganic salts.

[0229] (1) Sample determination: Weigh 0.3929 g of disodium lauroyl glutamate and 0.1788 g of sodium laurate, add 100 mL of deionized water, and adjust the pH to 11.5 with NaOH; transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0230] In a 100mL stoppered measuring cylinder, add 25.00mL of the test solution containing disodium lauroyl glutamate and sodium laurate, 10mL of indicator phosphate buffer II, 10mL of chloroform and 2.2g of n-propanol. After shaking, add 4mmol / L of Heming 1622 associating agent solution drop by drop. Shake vigorously 30 times after each addition. Pay attention to degassing in the middle. After stratification, observe the color of the chloroform layer. When the color of the indicator in the upper water layer is completely transferred to the lower layer and turns sky blue, the titration end point is reached. The titration time is 120min.

[0231] (2) Blank test: Replace the above 25.00 mL of disodium lauroyl glutamate and sodium laurate test solution with 25.00 mL of ultrapure water to conduct a blank test.

[0232] After deducting the volume of the blank consumed associative agent solution, the titration consumed 20.73 mL of Haiming 1622 associative agent solution, and the molar ratio of the Haiming 1622 associative agent consumed in the titration to sodium laurate and disodium lauroyl glutamate was 0.447, while theoretically sodium laurate accounts for 0.433 of the total and disodium lauroyl glutamate accounts for 0.567, indicating that disodium lauroyl glutamate and sodium laurate associate with Haiming 1622 in the mixed medium, and in a non-stoichiometric ratio, further illustrating that the mixed medium not of the present invention is not suitable for determining the soap in the fatty acyl amino acid type surfactant, nor is it suitable for accurately determining the total content of fatty acyl amino acid salts and fatty acid soaps in the system.

[0233] Comparative Example 3

[0234] The content of sodium laurate in sodium lauroyl glutamate product was determined using hexadecyltributylphosphonium bromide as an associating agent.

[0235] (1) Sample determination: 25.00 mL of the test solution A2 in Example 8 was transferred into a 100 mL stoppered measuring cylinder, and then 10 mL of the indicator phosphate buffer II, 10 mL of chloroform, 2.25 g of Na2SO4 and 2.2 g of n-propanol were added. After shaking, the solution was titrated with a 2 mmol / L hexadecyltributylphosphonium bromide associating agent solution. At the beginning, about 1 mL was added each time. When the stratification speed became significantly faster, the amount of addition was reduced. During this period, the solution was vigorously shaken 30 times after each addition. During this period, air was released. After complete stratification, the color of the chloroform layer was observed. When the upper layer indicator was completely transferred to the lower layer and turned sky blue, the titration endpoint was reached. The titration time exceeded 12 h.

[0236] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0237] The titration was repeated 3 times in total, and the volume of the associating agent solution consumed by the blank was deducted. The volume of the associating agent solution consumed by the titration exceeded 50.00 mL and did not reach the titration endpoint. Combined with the concentration of the associating agent of the hexadecyl tributyl phosphonium bromide, the dilution ratio of the sodium lauroyl glutamate liquid product, the molecular weight of the sodium lauroyl glutamate and the molecular weight of the sodium laurate, it can be seen that the consumption of the titrant has exceeded twice the total mass of the sodium lauroyl glutamate and the sodium laurate. The above results show that the volume of the titrant solution consumed by the titration has far exceeded the results in Example 8, indicating that the association of the hexadecyl tributyl phosphonium bromide with the fatty acid soap and the fatty acyl amino acid salt is not significant, further indicating that the hexadecyl tributyl phosphonium bromide is not suitable for accurately determining the soap in the fatty acyl amino acid type surfactant, nor is it suitable for accurately determining the total content of the fatty acyl amino acid salt and the fatty acid soap in the system.

[0238] Comparative Example 4

[0239] The content of sodium laurate in sodium lauroyl glutamate product was determined using N,N'-bis(dodecyldimethyl)-1,2-dibromide ethylenediammonium salt as an associating agent.

[0240] (1) Sample determination: 25.00 mL of the test solution A2 in Example 8 was transferred into a 100 mL stoppered measuring cylinder, and then 10 mL of the indicator phosphate buffer II, 10 mL of chloroform, 2.25 g of Na2SO4 and 2.2 g of n-propanol were added. After shaking, the solution was titrated with 2 mmol / L of N,N'-bis(dodecyldimethyl)-1,2-ethylenediammonium dibromide associating agent solution. At the beginning, about 1 mL was added each time. When the stratification speed became significantly faster, the amount of addition was reduced. During this period, the solution was vigorously shaken 30 times after each addition. During this period, air was released. After complete stratification, the color of the chloroform layer was observed. When the upper layer indicator was completely transferred to the lower layer and turned sky blue, the titration endpoint was reached. The titration time was 97 min.

[0241] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0242] The titration was repeated three times in total. After deducting the volume of the blank consumed associative agent solution, the average volume of N,N'-bis(dodecyldimethyl)-1,2-dibromide ethylenediammonium salt associative agent solution consumed in the titration was 6.92 mL. Combined with the concentration of N,N'-bis(dodecyldimethyl)-1,2-dibromide ethylenediammonium salt associative agent, the dilution ratio of sodium lauroyl glutamate liquid product A and the molecular weight of sodium laurate, the mass percentage of sodium laurate in the product was calculated to be 3.53%.

[0243] The results show that the measured value is much higher than the measurement results of the liquid chromatography method in Example 8 and the method of the present invention, indicating that N,N'-bis(dodecyldimethyl)-1,2-dibromide ethylenediammonium salt associates with the fatty acid soap and fatty acyl amino acid salt in the system in a non-stoichiometric ratio, further illustrating that N,N'-bis(dodecyldimethyl)-1,2-dibromide ethylenediammonium salt is not suitable for accurately determining the soap in fatty acyl amino acid type surfactants, nor is it suitable for accurately determining the total content of fatty acyl amino acid salts and fatty acid soaps in the system.

[0244] Comparative Example 5

[0245] The content of sodium laurate in sodium lauroyl glutamate product was determined using N,N,N-trimethyllauroylpropylenediamine bromide as an associative agent.

[0246] (1) Sample determination: 25.00 mL of the test solution A2 in Example 8 was transferred into a 100 mL stoppered measuring cylinder, and then 10 mL of the indicator phosphate buffer II, 10 mL of chloroform, 2.25 g of Na2SO4 and 2.2 g of n-propanol were added. After shaking, the solution was titrated with a 2 mmol / L N,N,N-trimethyllauroylpropylenediamine bromide associating agent solution. At the beginning, about 1 mL was added each time. When the stratification speed became significantly faster, the amount of addition was reduced. During this period, the solution was vigorously shaken 30 times after each addition. During this period, air was released. After complete stratification, the color of the chloroform layer was observed. When the upper layer indicator was completely transferred to the lower layer and turned sky blue, the titration endpoint was reached. The titration time was 100 min.

[0247] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0248] The titration was repeated three times in total. The average volume of N,N,N-trimethyl lauroyl propylenediamine bromide associating agent solution consumed in the titration was 3.19 mL. Based on the concentration of N,N,N-trimethyl lauroyl propylenediamine bromide associating agent, the dilution ratio of sodium lauroyl glutamate liquid product A and the molecular weight of sodium laurate, the mass percentage of sodium laurate in the product was calculated to be 1.63%.

[0249] The above results show that the measured value is much lower than the measurement results of the liquid chromatography method in Example 8 and the method of the present invention, indicating that N,N,N-trimethyl lauroyl propylenediamine bromide is associated with the fatty acid soap in a non-stoichiometric ratio, further illustrating that N,N,N-trimethyl lauroyl propylenediamine bromide is not suitable for quantitative analysis of the fatty acid soap content in the fatty acyl amino acid salt surfactant.

[0250] Comparative Example 6

[0251] Quantitative analysis of sodium laurate in sodium lauroyl glutamate products at pH 9.

[0252] (1) Sample determination: 25.00 mL of the test solution A2 in Example 8 was transferred into a 100 mL stoppered measuring cylinder and the pH was adjusted to 9 with 0.5 mol / L HCl. Then, 10 mL of 0.6 mol / L indicator phosphate buffer with a pH of 9, 10 mL of chloroform, 2.25 g of Na2SO4 and 2.2 g of n-propanol were added. After shaking, the solution was titrated dropwise with 2 mmol / L of Heming 1622 associating agent solution. After each drop, the solution was vigorously shaken 30 times, and air was released in between. After complete stratification, the color of the chloroform layer was observed. The titration endpoint was reached when the upper layer indicator was completely transferred to the lower layer and turned sky blue. The titration time was 54 min.

[0253] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0254] The titration was repeated three times in total, and the average volume of the Haiming 1622 associative agent solution consumed in the titration was 1.92 mL. Based on the concentration of the Haiming 1622 associative agent, the dilution ratio of the sodium lauroyl glutamate liquid product A and the molecular weight of sodium laurate, the mass percentage of sodium laurate in the product was calculated to be 0.98%.

[0255] The above results show that the measured value is much lower than the results of the liquid chromatography method in Example 8 and the method of the present invention, indicating that under this condition, the associating agent and sodium laurate are associated in a non-stoichiometric ratio, further indicating that pH 9 is not suitable for quantitative analysis of fatty acid soaps in fatty acyl amino acid salts.

[0256] Comparative Example 7

[0257] Determination of sodium laurate content in sodium lauroyl glutamate products in a mixed medium containing excess inorganic salts and low-carbon alcohols.

[0258] (1) Sample determination: 25.00 mL of the test solution A2 in Example 8 was transferred into a 100 mL stoppered measuring cylinder, and then 10 mL of the indicator phosphate buffer II, 10 mL of chloroform, 6.00 g of Na2SO4 and 6.00 g of n-propanol were added. After shaking, the solution was titrated with 2 mmol / L of Heming 1622 associating agent solution. At the beginning, about 1 mL was added each time. When the stratification speed became obviously faster, the amount of addition was reduced. During this period, the solution was vigorously shaken 30 times after each addition. Pay attention to degassing in the middle. After complete stratification, the color of the chloroform layer was observed. When the upper layer indicator was completely transferred to the lower layer and turned sky blue, the titration end point was reached. The titration time was more than 12 h.

[0259] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0260] The sample was titrated repeatedly for 3 times in total, and the average volume of the Haiming 1622 associating agent solution consumed in the titration was 4.16 mL. Based on the concentration of the Haiming 1622 associating agent, the dilution ratio of the sodium lauroyl glutamate liquid product A and the molecular weight of sodium laurate, the mass percentage of sodium laurate in the product was calculated to be 1.12%. The measured value was much lower than the results of the liquid chromatography method in Example 8 and the method of the present invention, indicating that in the mixed medium of excess inorganic salts and low-carbon alcohols, the associating agent and the fatty acid soap are associated in a non-stoichiometric ratio, and therefore is not suitable for quantitative analysis of fatty acid soaps in fatty acyl amino acid salts.

[0261] Comparative Example 8

[0262] Determination of sodium lauroylthreonate content.

[0263] (1) Sample determination: Weigh 0.3234 g of sodium lauroylthreonate, add 100 mL of deionized water, and adjust the pH to 11.0 with NaOH; transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0264] In a 100mL stoppered measuring cylinder, add 25.00mL of sodium lauroylthreonine test solution, 15mL of indicator phosphate buffer I, 10mL of chloroform and 3.3g of methanol respectively. After shaking well, add 4mmol / L of Heming 1622 associating agent solution drop by drop. Shake vigorously 30 times after each addition. Pay attention to degassing in the middle. After stratification, observe the color of the chloroform layer. When the color of the indicator in the upper water layer is completely transferred to the lower layer and turns sky blue, the titration end point is reached.

[0265] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0266] After deducting the volume of the blank consumed associative agent solution, the titration consumed 20.83 mL of Heming 1622 associative agent solution, and the stoichiometric ratio of consumed Heming 1622 associative agent to sodium lauroyl glycinate was 0.850, indicating that Heming 1622 associative agent can associate with sodium lauroyl threonate in a non-stoichiometric ratio. It can be deduced that it is not suitable for quantitative analysis of fatty acid soaps in fatty acyl threonate salts, nor is it suitable for quantitative analysis of the total amount of fatty acyl threonate salts and fatty acid soaps.

[0267] Comparative Example 9

[0268] Determination of sodium lauroyl-β-alanine and sodium laurate content.

[0269] (1) Sample determination: Weigh 0.3480 g of sodium lauroyl-β-alanine and 0.1788 g of sodium laurate, add 100 mL of deionized water, and adjust the pH to 11.5 with NaOH; transfer to a 250 mL volumetric flask and dilute to obtain the test solution.

[0270] In a 100mL stoppered measuring cylinder, add 10.00mL of sodium lauroyl-β-alanine test solution, 10mL of indicator phosphate buffer II, 10mL of chloroform, 2.25g of Na2SO4 and 2.2g of n-propanol. After shaking, add 4mmol / L of Heming 1622 associating agent solution drop by drop. Shake vigorously 30 times after each addition. Pay attention to degassing in the middle. After stratification, observe the color of the chloroform layer. When the color of the indicator in the upper water layer is completely transferred to the lower layer and turns sky blue, the titration end point is reached.

[0271] (2) Blank test: Replace the above 25.00 mL of the test solution A2 with 25.00 mL of ultrapure water and conduct a blank test.

[0272] After deducting the volume of the blank consumed associative agent solution, the titration consumed 49.29 mL of the associative agent solution of Haiming 1622. The ratio of the associative agent consumed by titration to the total amount of sodium laurate and sodium lauroyl-β-alanine was 0.9904, indicating that Haiming 1622 associates with sodium laurate and sodium lauroyl-β-alanine in a stoichiometric ratio. This method can be used to measure the total content of sodium lauroyl-β-alanine and sodium laurate, but the content of sodium laurate therein cannot be measured.

Claims

1. A method for determining the fatty acid / soap content in a fatty acylamino acid / salt product, characterized in that: The method comprises: using a cationic surfactant as an associative agent and bromocresol green as an indicator; using an indicator buffer, a low-carbon alcohol, an inorganic salt and a chloroalkane as a mixed medium; dropping the associative agent into a mixed solution consisting of a fatty acyl amino acid / salt product to be tested and the mixed medium under a pH condition of 10 to 12.5; shaking the mixed solution to allow rapid distribution equilibrium until the indicator is completely transferred from the aqueous phase to the chloroalkane phase and turns sky blue, recording the volume of the consumed associative agent solution, and calculating the fatty acid / soap content in the fatty acyl amino acid salt product according to the concentration of the associative agent, the dilution ratio of the sample and the molecular weight of the fatty acid / soap; The cationic surfactant includes one or more of Heming 1622, dodecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, dodecyldimethylbenzylammonium chloride, dodecyldimethylbenzylammonium bromide, tetradecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide, tetradecyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium bromide, hexadecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, hexadecyldimethylbenzylammonium chloride, hexadecyldimethylbenzylammonium bromide, octadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, octadecyldimethylbenzylammonium chloride, and octadecyldimethylbenzylammonium bromide; The mass ratio of the low-carbon alcohol to the inorganic salt in the mixed medium is (1:18) to (1:2); The low-carbon alcohol is one or more of methanol, ethanol, n-propanol, and isopropanol; The inorganic salt is one or both of sodium chloride and sodium sulfate; The general formula of the fatty acyl amino acid / salt is: M is one or more of octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl, linoleoyl, arachidoyl, behenoyl, erucoyl, coconut oil, palm kernel oil, soybean oil, camellia oil, tallow oil, sunflower oil and sesame oil; M + H + , Na + , K + NH4 + NH2 + (CH2CH2OH)2、NH + (CH2CH2OH)3、NH + (CH3)3 or NH + One or more of (CH2CH3)3; n is 1 or 2; The general formula of the fatty acid / soap is: M is one or more of octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, stearoyl, oleoyl, linoleoyl, arachidoyl, behenoyl, erucoyl, coconut oil, palm kernel oil, soybean oil, camellia oil, tallow oil, sunflower oil and sesame oil; M + H + , Na + , K + NH4 + NH2 + (CH2CH2OH)2、NH + (CH2CH2OH)3、NH + (CH3)3 or NH + (CH2CH3)3 or more.

2. The method according to claim 1, characterized in that The chlorinated alkane is one or more of chloroform, dichloromethane, carbon tetrachloride, dichloroethane, trichloroethane and tetrachloroethane.

3. The method according to claim 1, characterized in that The mass fraction of the chloroalkane is 11% to 32% based on the total mass of the mixed medium.

4. Use of the method according to any one of claims 1 to 3 in the quantitative analysis of the components of fine chemical products.

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