GB/T 5173-1995 Determination of anionic active matter in surfactants and detergents - Direct two-phase titration method
Some standard content:
National Standard of the People's Republic of China
Surface active agents and detergents
Determination of anionic-active matter by direct two-phase titration procedure Surface active agents and detergents-Determination of anionic-active matter by direct two-phase titration procedure GB/T5173-1995
Replaces GB5173--85
This standard equivalently adopts the international standard ISO2271:1989 "Surface active agents-detergents-Determination of anionic-active matter by manual or mechanical direct two-phase titration".
This standard only adopts the manual titration method specified in ISO2271, and adds ethidium bromide and dibromide to the mixed indicator for use in parallel, but dibromide is still used in arbitration. Subject content and scope of application
This standard specifies the two-phase titration method for the determination of anionic active matter in anionic surfactants and detergents. This standard is applicable to the analysis of solid or liquid products of alkylbenzene sulfonates, alkyl sulfonates, alkyl sulfates, alkyl hydroxysulfates, alkylphenol sulfates, fatty alcohol methoxy and ethoxy sulfates and dialkyl succinate sulfonates, as well as other anionic active substances containing one hydrophilic group per molecule.
This standard is not applicable to products with cationic surfactants. If the analysis results are expressed as mass percentage, the relative molecular weight of the anionic active substance must be known or determined in advance. Note: ① When the content of low relative molecular weight sulfonates (toluene and xylene sulfonates) used as water cosolvents in detergents is less than 15% of the anionic active substance, it will not interfere with the analysis results, but when it is higher than 15%, its influence should be estimated. ② Soap, urea, ethylenediaminetetraacetate and sodium carboxymethyl cellulose do not interfere. ③ When non-hyperionic surfactants are present, their influence needs to be estimated according to each special case. ③Typical inorganic components in detergent formulas, such as sodium fluoride, sodium sulfate, sodium borate, tripolyphosphate, sodium perborate, sodium silicate, etc., do not interfere, but bleaching agents other than sodium perborate should be destroyed before analysis, and the sample should be completely dissolved in water. 2 Reference Standards
GB/T13173.1 Detergent Sample Splitting Method
3 Principle
In a two-phase medium of water and trifluoromethane, in the presence of an acidic mixed indicator, titrate with a cationic surfactant [benzyl chloride (Ben-zethonium chloride) to determine the anionic active matter. Note: The titration reaction process is as follows: the anionic active matter and the cationic dye generate salt, which dissolves in chloroform, making the trifluoromethane layer pink. During the titration process, all anionic active substances in the aqueous solution react with ammonium thiourea, and benzylthiourea chloride replaces the cationic dye (bromobenzene) in the anionic active substance-cationic dye salt. The bromobenzene is transferred into the water layer, and the red color of the chloroform layer fades. A slightly excessive amount of thiourea chloride forms a salt with the anionic dye (acid blue-1), which dissolves in the chloroform layer and turns it blue. Approved by the State Administration of Technical Supervision on December 8, 1995 and implemented on August 1, 1996
4 Reagents
GB/T 5173-1995
Analytical reagents and distilled or deionized water should be used in the analysis. 4.1 Trifluoromethane (GB682).
4.2 Sulfuric acid (GB625), 245g/L solution.
HzSO) 0.5mol/L standard solution.
4.3 Sulfuric acid, c(-
4.4 Sodium hydroxide (GB629), c(NaOH)=0.5mol/L standard solution. 4.5 Sodium lauryl sulfate, c[CH,(CH,)nOSO,Na)=0.004mol/L standard solution. The sodium lauryl sulfate used is determined by gas-liquid chromatography, and the components less than C should be less than 1.0%. If drying is required before use, the temperature should not exceed 60℃.
Inspect the purity of sodium lauryl sulfate and prepare the standard solution at the same time. 4.5.1 Determination of the purity of sodium lauryl sulfate
Weigh 2.5±0.2g sodium lauryl sulfate (reagent grade), weigh to 1mg, put it in a 250mL round-bottom glass flask with a frosted neck, accurately add 25mL sulfuric acid standard solution (4.3), install a water condenser, and place the flask in a boiling water bath and heat for 60min. In the first 5 to 10 minutes, the solution will become thick and tend to foam strongly. This can be controlled by removing the flask from the heat source and swirling the contents of the flask. After another 10 minutes, the solution will become clear and stop foaming. Move it to the hot plate and heat it under reflux for 90 minutes. Remove the heat source, cool the flask, and carefully rinse the condenser with 30 mL of ethanol and then water. Add a few drops of phenolic acid solution (4.7) and titrate with sodium hydroxide standard solution (4.4). Use sodium hydroxide solution (4.4) to titrate 25 mL of sulfuric acid solution (4.3) for a blank test. The purity of sodium lauryl sulfate is expressed in millimole per gram (mmol/g) and is calculated according to formula (1): (V,-Vo)ci
Purity of sodium lauryl sulfate, mmol/g; where: P——
Volume of sodium hydroxide solution consumed in blank test, mL; Vi—Volume of sodium hydroxide solution consumed in sample, mL; c.---Concentration of sodium hydroxide solution, mol/L; mMass of sodium lauryl sulfate, g.
4.5.2 Preparation of 0.004mol/L sodium lauryl sulfate standard solution: (1)
Weigh 1.14-1.16g sodium lauryl sulfate, weigh to 1mg, and dissolve in 200mL water, transfer to a 1000mL volumetric flask, and dilute to the mark with water. The concentration c2 of the solution is expressed as (C12H2SO,Na) moles per liter (mol/L), calculated according to formula (2): C2
Wherein: m2---mass of sodium lauryl sulfate, g; P-purity of sodium lauryl sulfate, mmol/g. m2·P
4.6 Chlorinated taro c(CzHazCINO,)=0.004mol/L standard solution*(2)
Benzethonium Chloride-taro dimethyl-2[2-4(1,13,3-tetramethylbutyl)phenoxy-ethoxy}-ethylammonium chloride monohydrate [(CH,),C-CH2-C(CH,)2-CH,OCH2CH,OCH,CH2-N(CH),CH,C,Hs+CI-· H,O. Note: Hyamine 1622 is the applicable product. When this reagent is not available, other cationic reagents such as hexadecyltrimethylammonium bromide, dodecyldimethylammonium bromide or chloride may be used. However, only benzylthrene chloride is used for arbitration. 4.6.1° Preparation of solution
Weigh 1.75~1.85g of benzylthrene chloride, weigh to the nearest 1mg, dissolve in water and transfer quantitatively to a 1000mL volumetric flask, and dilute with water to the mark.
Note: To prepare a 0.004mol/L solution, dry benzylthrene chloride at 105℃, cool in a desiccator, weigh 1.792g, weigh to the nearest 1mg, dissolve in water, and dilute to 1000mL.
4.6.2 Solution calibration
GB/T5173-1995
4.6.2.1 Use a pipette (5.4) to transfer 25.0 mL of sodium lauryl sulfate standard solution (4.5) to a stoppered measuring cylinder (5.1), add 10 mL of water, 15 mL of chloroform (4.1), and 10 mL of acidic mixed indicator solution (4.8.2). 4.6.2.2 Titrate with benzyl chloride solution (4.6.1). At the beginning, add about 2 mL of titration solution each time, plug the stopper, shake thoroughly, let stand to separate the layers, and the lower layer will be pink. Continue titrating and shaking. When the titration end point is approaching, the emulsion formed by shaking is easier to break. Then titrate drop by drop and shake thoroughly. When the pink color of the chloroform layer completely fades and turns light gray-blue, the end point is reached. 4.6.3 Calculation of concentration
The concentration of benzyl chloride solution c3, expressed as (CzH42CINO2) moles per liter (mol/L), is calculated according to formula (3): C3
Wherein: c2---the concentration of sodium lauryl sulfate standard solution, mol/L, V2--the volume of benzyl chloride solution consumed during titration, mL. 4.7 Phenolphthalein (GB10729), 10g/L ethanol solution Dissolve 1g phenolphthalein in 100mL 95% ethanol (GB679). 4.8 Mixed indicator
4.8.1 Storage solution
Prepare from anionic dye - acid blue-1 and cationic dye - dimethicone or ethidium bromide.
4.8.1.1 Acid blue-1 [4,4'-bis(diethylamino)triphenylmethane-2\,4\-disulfonic acid disodium]. NaO,S
(C,H)2N
N+(C,H,)2
4.8.1.2 Dimidiumbromide (3,8-diamino-5-methyl-6-phenylphenanthridine bromide)]-NH2
4.8.1.3 Ethidiumbromide (3,8-diamino-5-ethyl-6-phenylphenanthridine bromide)) (3)
Instructions for use:
1] ISO2271 only specifies the use of dimidiumbromide, not ethidiumbromide. Tests show that the analysis results of ethidiumbromide and dimidiumbromide are the same, but dimidiumbromide should be used in arbitration.
4.8.1.4 Preparation of stock solution
GB/T 51731995
CH,CH,Br
Weigh 0.5±0.005g of ethidium bromide (4.8.1.2) or ethidium bromide (4.8.1.3) in a 50mL beaker, and weigh 0.25±0.005g of acid blue-1 (4.8.1.1) in another 50mL beaker, and weigh to the nearest 1mg. Add 20~30mL of 10% (V/V) hot ethanol to each beaker and stir to dissolve. Transfer the two solutions to a 250mL volumetric flask, rinse the beaker with 10% ethanol, add the washing solution into the volumetric flask, and dilute to the mark. 4.8.2 Acidic mixed indicator solution
Pipette 20mL of the stock solution (4.8.1) into a 500mL volumetric flask, add 200mL of water, then add 20mL of 245g/L sulfuric acid (4.2), dilute to the mark with water and mix. Store in a dark place. 5 Apparatus 1)
Ordinary laboratory apparatus, and:
5.1 Glass volume with stopper, 100mL,
5.2 Burette, 25mL and 50mL;
5.3 Volumetric flask, 250mL, 500mL and 1000mL; 5.4 Pipette, 25mL.
Preparation of test sample
Prepare and store laboratory samples in accordance with the provisions of GB/T13173.1. 7 Procedure
Precautions: Due to the toxicity of chloroform, the operation should be carried out in a fume hood or a well-ventilated environment. 7.1 Test portion
Weigh a laboratory sample containing 3~～5mmol of anionic active substances, weigh to the nearest 1 mg, and place it in a 150mL beaker. Table 1 shows the sample size calculated based on the relative molecular weight of 360, which can be used as a reference. Table 1 Test portion mass
Active substance content in sample, %(m/m)
Instructions for use:
Test portion mass, g
11IS(）2271 also specifies automatic burettes and titration cells for mechanical titration, which are not specified in this standard. 6
7.2 Determination
GB/T 5173—1995
Dissolve the test portion in water, add a few drops of phenolic acid solution (4.7), and neutralize with sodium hydroxide solution (4.4) or sulfuric acid solution (4.3) as needed until it turns light pink. Transfer quantitatively to a 1000mL volumetric flask (5.3), dilute to the mark with water, and mix. Use a pipette (5.4) to transfer 25mL of the sample solution to a stoppered measuring cylinder (5.1), add 10mL of water, 15mL of chloroform (4.1) and 10mL of acidic mixed indicator solution (4.8.2), and titrate to the endpoint with benzyl fluoride solution (4.6) as described in 4.6.2.2. 8 Expression of results
8.1 Calculation
The anionic active matter content X is expressed in mass percentage (%) and is calculated according to formula (4): X4×V, Xc,×M
The anionic active matter content mB is expressed in millimole per gram (mmol/g) and is calculated according to formula (5): mB = 40 × V,× cs
Wherein: X-
-anionic active matter content, %,
sample mass, name,
M,-average relative molecular weight of anionic active matter, C
-concentration of taro chloride solution, mol/L,-volume of taro chloride solution consumed during titration, mL, V3
mB-anionic active matter content, mmol/g. 8.2 Precision
8.2.1 Repeatability
For the same sample, the difference between two consecutive determinations by the same analyst using the same instrument shall not exceed 1.5% of the average value. 8.2.2 Reproducibility
For the same sample, the difference between the results obtained in two different laboratories shall not exceed 3% of the average value. 9 Test report
The test report shall include the following items:
The method used;
The results obtained and the method of expression;
Operations not specifically specified in the standard or added, and any unexpected phenomena that may affect the results; the name, type, grade status and manufacturer of the sample, the test date and the test personnel.
Additional remarks:
This standard is proposed by the China Light Industry General Association.
This standard is under the jurisdiction of the National Surfactant Detergent Standardization Center. This standard was drafted by the Shanghai Daily Chemical Industry Research Institute. The main drafters of this standard are: Pan Haiyan, Kong Jiahua, Gan Pingping. 4
（5）×M
The anionic active matter content mB is expressed in millimoles per gram (mmol/g) and is calculated according to formula (5): mB = 40 × V,× cs
Where: X-
-anionic active matter content, %,
sample mass, name,
M,-average relative molecular weight of anionic active matter, C
-concentration of taro chloride solution, mol/L,-volume of taro chloride solution consumed during titration, mL, V3
mB-anionic active matter content, mmol/g. 8.2 Precision
8.2.1 Repeatability
For the same sample, the difference between two consecutive determinations by the same analyst using the same instrument should not exceed 1.5% of the average value. 8.2.2 Reproducibility
For the same sample, the difference between the results obtained in two different laboratories should not exceed 3% of the average value. 9 Test report
The test report shall include the following items:
The method used;
The results obtained and the method of expression;
Operations not specified in the standard or added, and any unexpected phenomena that may affect the results; the name, type, grade status and manufacturer of the test specimen, the test date and the test personnel.
Additional remarks:
This standard is proposed by the China Light Industry General Association.
This standard is under the jurisdiction of the National Surfactant Detergent Standardization Center. This standard was drafted by the Shanghai Daily Chemical Industry Research Institute. The main drafters of this standard are: Pan Haiyan, Kong Jiahua, Gan Pingping. 4
(5)×M
The anionic active matter content mB is expressed in millimoles per gram (mmol/g) and is calculated according to formula (5): mB = 40 × V,× cs
Where: X-
-anionic active matter content, %,
sample mass, name,
M,-average relative molecular weight of anionic active matter, C
-concentration of taro chloride solution, mol/L,-volume of taro chloride solution consumed during titration, mL, V3www.bzxz.net
mB-anionic active matter content, mmol/g. 8.2 Precision
8.2.1 Repeatability
For the same sample, the difference between two consecutive determinations by the same analyst using the same instrument should not exceed 1.5% of the average value. 8.2.2 Reproducibility
For the same sample, the difference between the results obtained in two different laboratories should not exceed 3% of the average value. 9 Test report
The test report shall include the following items:
The method used;
The results obtained and the method of expression;
Operations not specified in the standard or added, and any unexpected phenomena that may affect the results; the name, type, grade status and manufacturer of the test specimen, the test date and the test personnel.
Additional remarks:
This standard is proposed by the China Light Industry General Association.
This standard is under the jurisdiction of the National Surfactant Detergent Standardization Center. This standard was drafted by the Shanghai Daily Chemical Industry Research Institute. The main drafters of this standard are: Pan Haiyan, Kong Jiahua, Gan Pingping. 4
(5)
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