ASTM D3049-89(1996)e1

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
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e1
Designation: D 3049 – 89 (Reapproved 1996)
Standard Test Method for
Synthetic Anionic Ingredient by Cationic Titration
This standard is issued under the fixed designation D 3049; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Keywords were added editorially in February 1996.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of the amount 2.1 ASTM Standards:
of synthetic anionic ingredient in a surfactant by direct titration D 1193 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
3.1 An aqueous solution of an anionic-type detergent, to
the anionic material. The end point is detected by the transfer
of a colored complex from an organic solvent phase to an which is added a small amount of mixed indicator (dimidium
aqueous phase. The colored complex is formed by the addition bromide and disulphine blue), is shaken with aqueous Hyamine
solution and chloroform. The pink complex which is formed by
of a solution of dye to a solution of the anionic surfactant. This
complex is soluble in the organic-solvent phase and insoluble the reaction between the anionic detergent and the cationic dye,
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
from the colored complex and, being water-soluble, migrates to
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
has been standardized against a characterized anionic agent can
be used to analyze for other anionics of known molecular mass. 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 This test method is not affected by low molecular weight
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
statement appears in Section 7. Material Safety Data Sheets are
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,
and silicates do not interfere. Soaps, urea, and ethylenedi-
This test method is under the jurisdiction of ASTM Committee D-12 on Soaps
aminetetraacetic acid salts do not interfere. Bleaching agents
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on
Analysis of Soaps and Synthetic Detergents.
Current edition approved May 26, 1989. Published July 1989. Originally
published as D 3049 – 72 T. Last previous edition D 3049 – 88. Annual Book of ASTM Standards, Vol 11.01.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 3049
other than perborate should be destroyed prior to performing 7. Safety Precaution
this analysis. Low molecular weight sulfonates, such as those
7.1 This test method includes the use of small amounts of
of toluene and xylene, do not interfere when present up to 15 %
chloroform. Appropriate safety practices, such as those in-
(w) of active material. Since the titration is performed under
cluded in the Material Safety Data Sheets for chloroform,
acidic conditions (about pH 2.0), care should be exercised
should be employed. Good ventilation is especially important.
when using this procedure on products containing significant
8. Primary Standard
amounts of alkaline materials, such as carbonates and silicates,
to ensure that the final solution is being titrated in the proper 8.1 The primary standard used in this procedure is sodium
pH range. lauryl sulfate. Three tests are made on this primary standard as
follows:
6. Reagents 8.2 Purity:
8.2.1 This test should be run in duplicate.
6.1 Purity of Reagents—Reagent grade chemicals shall be
8.2.2 Weigh, to the nearest 0.1 mg, 10 6 0.2 g of the
used in all tests. Unless otherwise indicated, it is intended that
primary standard into a 250-mL round-bottom flask.
all reagents shall conform to the specifications of the Commit-
8.2.3 Add exactly 25 mL of 0.5 N H SO . It is not necessary
2 4
tee on Analytical Reagents of the American Chemical Society,
to standardize this acid.
where such specifications are available. Other grades may be
8.2.4 Reflux under a water condenser for 2 h. Heat moder-
used, provided it is first ascertained that the reagent is of
ately in the beginning until the solution clarifies and the
sufficiently high purity to permit its use without lessening the
foaming ceases; then increase the heat input until a vigorous
accuracy of the determination.
reflux is attained.
6.2 Purity of Water—Unless otherwise indicated, references
8.2.5 Remove the heat source, cool the flask, and then wash
to water shall be understood to mean reagent water conforming
down the condenser with approximately 30 mL of ethanol
to Specification D 1193.
followed by 50 mL of water. Add the washings to the reaction
6.3 Chloroform.
flask.
6.4 Ethanol.
8.2.6 Disconnect the condenser and wash the point and the
6.5 Petroleum Ether, boiling range 30 to 50°C.
neck with water. Add these washings to the reaction flask.
6.6 Phenolphthalein Indicator Solution (1 %)—Dissolve 1
8.2.7 Add a few drops of 1 % phenolphthalein indicator
g of phenolphthalein in 95 % ethanol and dilute to 100 mL.
solution and titrate the H SO with standardized 1 N NaOH
2 4
6.7 Sodium Hydroxide, Standard Solution (0.1 N)—Prepare
solution.
a 0.1 N solution of sodium hydroxide (NaOH).
8.2.8 Determine a blank value by titrating 25 mL of the 0.5
6.8 Sodium Hydroxide, Standard Solution (1 N)—Prepare a
N H SO with the standardized 1 N NaOH solution. This
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1 N solution of NaOH.
should be done in duplicate and the average used.
6.9 Sodium Hydroxide, Standard Solution (50 %)—Prepare
8.2.9 Calculate the percent purity of the primary standard as
a 50 % solution of NaOH.
follows:
6.10 Sodium Lauryl Sulfate, Standard Solution, (0.004 M).
Purity, % 5 @28.84 3 ~A 2 B! 3 N#/W (2)
6.10.1 Weigh accurately between 1.14 and 1.16 g of sodium
lauryl sulfate and dissolve in 200 mL of water.
where:
6.10.2 Transfer to a stoppered graduated 1-L flask and dilute
A 5 NaOH solution used in sample titration, mL,
to volume with water.
B 5 NaOH solution used in blank titration, mL,
6.10.3 Calculate the molarity of the solution as follows:
N 5 normality of the NaOH solution, and
W 5 primary standard used, g.
Molarity 5 ~W 3 P!/~288.4 3 100! (1)
8.2.10 For best precision and accuracy, temperature and
where:
buret corrections should be made when titrating the hydroly-
W 5 sodium lauryl sulfate, g, and
sate of the sodium lauryl sulfate with 1 N NaOH solution.
P 5 purity of the sodium lauryl sulfate, %.
8.3 Alcohols:
6.11 Sodium Sulfate (Na SO ), anhydrous.
2 4
8.3.1 The primary standard, sodium lauryl sulfate, is sold as
6.12 Sulfuric Acid, Standard (0.1 N)—Prepare a 0.1 N
having not more than 1 weight % (Note 1) of a sum of decyl
solution of sulfuric acid (H SO ).
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and tetradecyl alcohol sulfates. The following test should be
6.13 Sulfuric Acid, Standard (0.5 N)—Prepare a 0.5 N
run in duplicate.
solution of H SO .
2 4
NOTE 1—The term “weight” is temporarily used in this standard
6.14 Sulfuric Acid, Standard (1 N)—Prepare a 1 N solution
because of established trade usage. The word is used to mean both “force”
of H SO .
2 4
and “mass,” and care must be taken to determine which is meant in each
case (SI unit for force 5 newton and for mass 5 kilogram).
8.3.2 Mix approximately5gof sodium lauryl sulfate with
Reagent Chemicals, American Chemical Society Specifications, American
25 mL of 1 N H SO in a 250-mL round-bottom flask.
2 4
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. Pharmaceutical 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.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest informat
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