ASTM D3049-89(2003)
(Test Method)Standard Test Method for Synthetic Anionic Ingredient by Cationic Titration
Standard Test Method for Synthetic Anionic Ingredient by Cationic Titration
SIGNIFICANCE AND USE
This test method offers a means of determining anionic detergents commonly found in laundry, dishwashing, and other cleaning materials. Accurate determination of the anionic active substance is highly important in assessing the cost and effectiveness of such cleaning substances.
This test method is not affected by low molecular weight sulfonates, such as those of toluene and xylene commonly found in detergent formulations, when these substances are present up to 15 weight % of active material.
SCOPE
1.1 This test method covers the determination of the amount of synthetic anionic ingredient in a surfactant by direct titration with a standardized cationic reagent. The test method is a simple and convenient means for the quantitative estimation of the anionic material. The end point is detected by the transfer of a colored complex from an organic solvent phase to an aqueous phase. The colored complex is formed by the addition of a solution of dye to a solution of the anionic surfactant. This complex is soluble in the organic-solvent phase and insoluble in the aqueous phase. When this solution is titrated with a standardized solution of a cationic reagent, the dye is displaced from the colored complex and, being water-soluble, migrates to the aqueous phase. Therefore, a cationic titrating solution that has been standardized against a characterized anionic agent can be used to analyze for other anionics of known molecular mass.
1.2 This test method is applicable to alkylaryl sulfonates, alkyl sulfonates, alkyl sulfates and hydroxy-sulfates, alkylphenol- and fatty alcohol ethoxy-sulfates and dialkylsulfosuccinates. It applies to active materials containing one hydrophilic group per molecule.
1.3 The analytical procedures appear in the following order:
SectionsReagents6Primary Standard8Purity8.2Alcohols8.3Free Acid or Alkali8.4Preparation of Mixed Indicator Solution9Preparation of Hyamine Solution10 Standardization of Hyamine Solution11General Procedure for Anionic-Active Material12
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. A precautionary statement appears in Section 7. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D3049–89(Reapproved2003)
Standard Test Method for
Synthetic Anionic Ingredient by Cationic Titration
This standard is issued under the fixed designation D3049; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 Thistestmethodcoversthedeterminationoftheamount 2.1 ASTM Standards:
of synthetic anionic ingredient in a surfactant by direct titration D1193 Specification for Reagent Water
with a standardized cationic reagent. The test method is a
3. Summary of Test Method
simple and convenient means for the quantitative estimation of
the anionic material. The end point is detected by the transfer 3.1 An aqueous solution of an anionic-type detergent, to
which is added a small amount of mixed indicator (dimidium
of a colored complex from an organic solvent phase to an
aqueous phase. The colored complex is formed by the addition bromideanddisulphineblue),isshakenwithaqueousHyamine
solutionandchloroform.Thepinkcomplexwhichisformedby
of a solution of dye to a solution of the anionic surfactant.This
complex is soluble in the organic-solvent phase and insoluble thereactionbetweentheanionicdetergentandthecationicdye,
dimidium bromide, is extracted into the chloroform. Incre-
in the aqueous phase. When this solution is titrated with a
standardized solution of a cationic reagent, the dye is displaced ments of additional Hyamine solution are added with a
thorough mixing after each addition.At first the reaction takes
fromthecoloredcomplexand,beingwater-soluble,migratesto
the aqueous phase. Therefore, a cationic titrating solution that place between the Hyamine and the excess anionic-type
detergent, during which there is no noticeable change in the
hasbeenstandardizedagainstacharacterizedanionicagentcan
beusedtoanalyzeforotheranionicsofknownmolecularmass. color (pink) of the chloroform phase.As the equivalence point
between the anionic and cationic materials is approached, the
1.2 This test method is applicable to alkylaryl sulfonates,
alkyl sulfonates, alkyl sulfates and hydroxy-sulfates, dimidium bromide portion of the anionic detergent active-
dimidium bromide complex (pink) is gradually released and
alkylphenol- and fatty alcohol ethoxy-sulfates and dialkylsul-
fosuccinates. It applies to active materials containing one transferred to the aqueous layer.As excess Hyamine is added it
reacts with the anionic dye, disulphine blue, to form a
hydrophilic group per molecule.
1.3 The analytical procedures appear in the following order: chloroform-soluble blue complex. During the transition at the
end point the chloroform layer, therefore, changes from pink to
Sections
Reagents 6
gray, to blue. The gray color is taken as the end point.
Primary Standard 8
Purity 8.2
4. Significance and Use
Alcohols 8.3
Free Acid or Alkali 8.4
4.1 This test method offers a means of determining anionic
Preparation of Mixed Indicator Solution 9
detergents commonly found in laundry, dishwashing, and other
Preparation of Hyamine Solution 10
cleaning materials. Accurate determination of the anionic
Standardization of Hyamine Solution 11
General Procedure for Anionic-Active Material 12
active substance is highly important in assessing the cost and
effectiveness of such cleaning substances.
1.4 This standard does not purport to address all of the
4.2 Thistestmethodisnotaffectedbylowmolecularweight
safety concerns, if any, associated with its use. It is the
sulfonates, such as those of toluene and xylene commonly
responsibility of the user of this standard to establish appro-
found in detergent formulations, when these substances are
priate safety and health practices and determine the applica-
present up to 15 weight % of active material.
bility of regulatory limitations prior to use. A precautionary
statementappearsinSection7.MaterialSafetyDataSheetsare
5. Interferences
available for reagents and materials. Review them for hazards
5.1 Normal inorganic components of detergent formula-
prior to usage.
tions, such as chloride, sulfate, borate, phosphates, perborate,
This test method is under the jurisdiction of ASTM Committee D12 on Soaps
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on
Analysis of Soaps and Synthetic Detergents. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 26, 1989. Published July 1989. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
published as D3049 – 72 T. Last previous edition D3049 – 88. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
D3049-89R03. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3049–89 (2003)
and silicates do not interfere. Soaps, urea, and ethylenedi- 6.14 Sulfuric Acid, Standard (1 N)—Prepare a 1 N solution
aminetetraacetic acid salts do not interfere. Bleaching agents of H SO .
2 4
other than perborate should be destroyed prior to performing
7. Safety Precaution
this analysis. Low molecular weight sulfonates, such as those
oftolueneandxylene,donotinterferewhenpresentupto15 %
7.1 This test method includes the use of small amounts of
(w) of active material. Since the titration is performed under
chloroform. Appropriate safety practices, such as those in-
acidic conditions (about pH 2.0), care should be exercised
cluded in the Material Safety Data Sheets for chloroform,
when using this procedure on products containing significant
should be employed. Good ventilation is especially important.
amounts of alkaline materials, such as carbonates and silicates,
8. Primary Standard
to ensure that the final solution is being titrated in the proper
pH range.
8.1 The primary standard used in this procedure is sodium
laurylsulfate. Threetestsaremadeonthisprimarystandardas
6. Reagents
follows:
6.1 Purity of Reagents—Reagent grade chemicals shall be
8.2 Purity:
used in all tests. Unless otherwise indicated, it is intended that
8.2.1 This test should be run in duplicate.
all reagents shall conform to the specifications of the Commit-
8.2.2 Weigh, to the nearest 0.1 mg, 10 6 0.2 g of the
tee onAnalytical Reagents of theAmerican Chemical Society,
primary standard into a 250-mL round-bottom flask.
where such specifications are available. Other grades may be
8.2.3 Addexactly25mLof0.5 NH SO .Itisnotnecessary
2 4
used, provided it is first ascertained that the reagent is of
to standardize this acid.
sufficiently high purity to permit its use without lessening the
8.2.4 Reflux under a water condenser for 2 h. Heat moder-
accuracy of the determination.
ately in the beginning until the solution clarifies and the
6.2 Purity of Water—Unless otherwise indicated, references
foaming ceases; then increase the heat input until a vigorous
to water shall be understood to mean reagent water conforming
reflux is attained.
to Specification D1193.
8.2.5 Remove the heat source, cool the flask, and then wash
6.3 Chloroform.
down the condenser with approximately 30 mL of ethanol
6.4 Ethanol.
followed by 50 mL of water.Add the washings to the reaction
6.5 Petroleum Ether, boiling range 30 to 50°C.
flask.
6.6 Phenolphthalein Indicator Solution (1 %)—Dissolve 1
8.2.6 Disconnect the condenser and wash the point and the
g of phenolphthalein in 95 % ethanol and dilute to 100 mL.
neck with water. Add these washings to the reaction flask.
6.7 Sodium Hydroxide, Standard Solution (0.1 N)—Prepare
8.2.7 Add a few drops of 1 % phenolphthalein indicator
a 0.1 N solution of sodium hydroxide (NaOH).
solution and titrate the H SO with standardized 1 N NaOH
2 4
6.8 Sodium Hydroxide, Standard Solution (1 N)—Prepare a
solution.
1 N solution of NaOH.
8.2.8 Determine a blank value by titrating 25 mL of the 0.5
6.9 Sodium Hydroxide, Standard Solution (50 %)—Prepare
N H SO with the standardized 1 N NaOH solution. This
2 4
a 50 % solution of NaOH.
should be done in duplicate and the average used.
6.10 Sodium Lauryl Sulfate, Standard Solution, (0.004 M).
8.2.9 Calculate the percent purity of the primary standard as
6.10.1 Weigh accurately between 1.14 and 1.16 g of sodium
follows:
lauryl sulfate and dissolve in 200 mL of water.
Purity, % 5 [28.84 3 ~A 2 B! 3 N]/W (2)
6.10.2 Transfertoastopperedgraduated1-Lflaskanddilute
to volume with water.
where:
6.10.3 Calculate the molarity of the solution as follows:
A = NaOH solution used in sample titration, mL,
Molarity 5 ~W 3 P!/~288.4 3 100! (1)
B = NaOH solution used in blank titration, mL,
N = normality of the NaOH solution, and
W = primary standard used, g.
where:
W = sodium lauryl sulfate, g, and 8.2.10 For best precision and accuracy, temperature and
P = purity of the sodium lauryl sulfate, %. buret corrections should be made when titrating the hydroly-
6.11 Sodium Sulfate (Na SO ), anhydrous. sate of the sodium lauryl sulfate with 1 N NaOH solution.
2 4
6.12 Sulfuric Acid, Standard (0.1 N)—Prepare a 0.1 N 8.3 Alcohols:
8.3.1 The primary standard, sodium lauryl sulfate, is sold as
solution of sulfuric acid (H SO ).
2 4
6.13 Sulfuric Acid, Standard (0.5 N)—Prepare a 0.5 N having not more than 1 weight % (Note 1) of a sum of decyl
and tetradecyl alcohol sulfates. The following test should be
solution of H SO .
2 4
run in duplicate.
NOTE 1—The term “weight” is temporarily used in this standard
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia Manufactured by British Drug House, Ltd. as Product No. 30176. It is sold as
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, being more than 99 % pure. It is available in the United States from Gallard-
MD. Schlesinger Chemical Manufacturing Corp., Carle Place, Long Island, NY 11514.
D3049–89 (2003)
because of established trade usage.The word is used to mean both “force”
the 1+10 ethanol-water solution and add the rinsings to the
and “mass,” and care must be taken to determine which is meant in each
volumetric flask. Dilute the stock solution to the mark with
case (SI unit for force = newton and for mass = kilogram).
deionized water. After 6 mont
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