ASTM D6173-97

Standard Test Method for Determination of Various Anionic Surfactant Actives by Potentiometric Titration

SCOPE
1.1 This test method is based on a potentiometric titration of common anionic surfactants and blends of anionic surfactant with a hydrotrope. This test method solely is intended for the analysis of active matter in the following surfactants: alcohol ether sulfate, alpha olefin sulfonate, alkylbenzene sulfonate/sodium xylene sulfonate blend (5:1), sodium alkylbenzene sulfonate/sodium xylene sulfonate blend (16:1), and sodium alkylbenzene sulfonate/sodium xylene sulfonate blend (22:1). It has not been tested for surfactant formulations.  
1.2 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. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to usage.

General Information

• Status: Historical
• Publication Date: 09-Sep-1997
• ICS: 71.040.99 - Other standards related to analytical chemistry
• Technical Committee: D12 - Soaps and Other Detergents
• Drafting Committee: D12.12 - Analysis and Specifications of Soaps, Synthetics, Detergents and their Components

Relations

• Replaced By: ASTM D6173-97(2005) - Standard Test Method for Determination of Various Anionic Surfactant Actives by Potentiometric Titration
• Effective Date: 01-May-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6173–97
Standard Test Method for
Determination of Various Anionic Surfactant Actives by
Potentiometric Titration
This standard is issued under the fixed designation D 6173; 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.
1. Scope 4. Summary of Test Method
4.1 This test method describes a potentiometric titration
1.1 Thistestmethodisbasedonapotentiometrictitrationof
common anionic surfactants and blends of anionic surfactant procedure for determining active matter in anionic surfactant.
with a hydrotrope. This test method solely is intended for the The anionic surfactant is first dissolved in water, and the pH of
analysis of active matter in the following surfactants: alcohol the solution is adjusted according to the type of anionic
ether sulfate, alpha olefin sulfonate, alkylbenzene sulfonic surfactant being measured. In the potentiometric titration the
acid, alcohol sulfate, sodium alkylbenzene sulfonate/sodium anionic surfactant is titrated with a standard solution of
xylene sulfonate blend (5:1), sodium alkylbenzene sulfonate/ Hyamineusingasurfactantelectrode,andthereactioninvolves
sodium xylene sulfonate blend (16:1), and sodium alkylben- the formation of a complex between the anionic surfactant and
zene sulfonate/sodium xylene sulfonate blend (22:1). It has not the cationic titrant (Hyamine), which then precipitates. At the
been tested for surfactant formulations. end point the surfactant electrode appears to respond to an
1.2 This standard does not purport to address all the safety excess of titrant with potential change large enough to give a
concerns, if any, associated with its use. It is the responsibility well defined inflection in the titration curve.
of the user of this standard to establish appropriate safety and
5. Significance and Use
health practices and determine the applicability of regulatory
limitations prior to use. Material Safety Data Sheets are 5.1 The most common anionic surfactants presented in this
test method are used widely in synthetic detergents and other
available for reagents and materials. Review them for hazards
prior to usage. household cleaners. Current analysis of the active matter in
these anionic surfactants involves the two-phase aqueous/
2. Referenced Documents
chloroform titration with a mixed indicator, organic dyes such
2.1 ASTM Standards: as disulphine blue/dimidium bromide (see Test Method
D 459 Terminology Relating to Soaps and Other Deter- D 3049), and methylene blue (see Test Method D 1681). This
gents test method eliminates the use of hazardous chloroform, the
D 1193 Specification for Reagent Water use of which is restricted for environmental and toxicological
D 1681 Test Method for Synthetic Anionic Active Ingredi- reasons.
ent in Detergents by Cationic Titration Procedure 5.2 This test method also describes the titration of various
D 3049 Test Method for Synthetic Anionic Ingredient by ratio blends of sodium alkylbenzene sulfonate and sodium
Cationic Titration xylene sulfonate. Active matter content in these blends is
E 180 Practice for Determining the Precision of ASTM attributable directly to sodium alkylbenzene sulfonate. There-
Methods forAnalysis and Testing of Industrial Chemicals fore, the presence of various amounts of sodium xylene
sulfonate in these blends does not interfere with the determi-
3. Terminology
nation of percent actives.
3.1 Definitions of Terms Specific to This Standard:
6. Apparatus
3.1.1 active matter, n—the organic surface-active material
present in the detergent.Also defined in Terminology D 459 as 6.1 Autotitration System, equipped with a delivery buret
,
5 6
active ingredient of detergents. system, 10 or 20-mL capacity.
This test method is under the jurisdiction ofASTM Committee D-12 on Soaps
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on The sole source of supply of the autotitration system and Phoenix electrode
Analysis of Soaps and Synthetic Detergents. known to the committee at this time is Brinkmann Instruments, Inc. Cantiague Rd.,
Current edition approved Sept. 10, 1997. Published February 1998. Westbury, NY 11590.
2 6
Annual Book of ASTM Standards, Vol 15.04. If you are aware of alternative suppliers, please provide this information to
Annual Book of ASTM Standards, Vol 11.01. ASTM headquarters.Your comments will receive careful consideration at a meeting
Annual Book of ASTM Standards, Vol 15.05. of the responsible technical committee, which you may attend.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6173
,
5 6
6.2 Phoenix Surfactant Combination Electrode , nitrate 0.1 mg. Dissolve in water and dilute to a final volume of 1L.
6,7
specific ion electrode, or surfactant electrode equipped with Calculate the normality of the solution according to the
silver/silver chloride reference electrode. The conditioning of following equation:
this type of electrode is essential for obtaining a good break in
W 3 P
Normality of Sodium Lauryl Sulfate 5 (1)
the titration curve. Therefore, each electrode should be condi-
~288.383 100!
tioned in sodium lauryl sulfate 0.0001M solution for 15 min.
where:
For other electrode requirements, follow the manufacturer’s
P 5 purity of the sodium lauryl sulfate, weight %, and
instruction manual.
W 5 weight of sodium lauryl sulfate, g.
6.3 Analytical Balance.
8.2 Keep the solution no longer than one month before
6.4 Standard Laboratory Glassware.
making a fresh solution.
-3
7. Reagents
8.3 Hyamine 1622 Solution,4 3 10 N—Dissolve 1.85 +
0.5 g of Hyamine 1622 in deionized water and dilute to a final
7.1 Hyamine 1622, diisobutylphenoxyethoxyethyl dimethyl
benzyl ammonium chloride monohydrate. volume of 1 L.
-3
7.2 Potassium Chloride, reagent grade.
8.4 Hyamine 1622 Solution Standardization,4 3 10
,
6 9
7.3 Triton X-100 , electrophoresis grade.
N—This determination shall be done in triplicate. Pipet 5.00
7.4 Potassium Chloride 4.0 M Solution—Prepare by weigh-
mL of the standard lauryl sulfate solution into a 150-mL
ing out 30.00 g to the nearest 0.01 g of potassium chloride into
beaker. Add 50 mL of dionized water, and, while stirring, add
a 100 mL volumetric glass and dissolving in deionized water.
1 mL of buffer solution pH 4 and 1 mL of Triton-X-100, 1 %
Dilute to the mark with deionized water.Add exactly one drop
solution. To minimize noise in the titration, make sure that the
of Triton X-100 to the solution and mix well. This is only a
buret tip is placed close to the center of the stir bar. Stir
reference electrode filling solution for the Phoenix electrode.
moderately. Erroneous results can occur if excessive foaming
7.5 Triton X-100, 1 % Solution—Prepare by weighing 1.00
takes place. Titrate potentiometrically with the Hyamine 1622
g of Triton X-100 into a 100-mL volumetric flask and diluting
solution and record the titration volume. The Titroprocessor
to the mark with deionized water.
will perform the titration, determine the inflection point and
6,10
7.6 Sodium Lauryl Sulfate , primary standard.
calculate the results according to the following equation:
N 3 5
NOTE 1—Sodium lauryl sulfate shall be analyzed for purity according
Normality of Hyamine 1622 5 (2)
to the reagent section of Test Method D 3049 before its use as primary V
standard.
where:
,
6 11
7.7 Buffer Solution pH 4.00
N 5 normality of sodium lauryl sulfate standard solution,
6,11
7.8 Buffer Solution pH 7.00 —Pipet 10 mL of buffer
5 5 sodium lauryl sulfate aliquot taken for titration, mL,
solution pH 7.00 and transfer to a 100-mL volumetric flask.
and
Dilute to volume and mix well.
V 5 Hyamine 1622 solution required to reach the endpoint,
7.9 Sodium Lauryl Sulfate 0.0001 m Solution, buffered at
mL.
pH 4.00, with a graduated cylinder transfer 2 mL of sodium
8.5 The electrode should be cleaned between each titration.
laurylsulfate0.004Msolutiontoa150-mLbeaker.Add80mL
A satisfactory procedure is to first rinse with the acid rinse
of deionized water and 1 mL of buffer solution pH 4.00 and
solution and then with deionized water. Bl
...