ASTM D6173-97(2005)
(Test Method)Standard Test Method for Determination of Various Anionic Surfactant Actives by Potentiometric Titration
Standard Test Method for Determination of Various Anionic Surfactant Actives by Potentiometric Titration
SIGNIFICANCE AND USE
The most common anionic surfactants presented in this test method are used widely in synthetic detergents and other household cleaners. Current analysis of the active matter in these anionic surfactants involves the two-phase aqueous/chloroform titration with a mixed indicator, organic dyes such as disulphine blue/dimidium bromide (see Test Method D 3049), and methylene blue (see Test Method D 1681). This test method eliminates the use of hazardous chloroform, the use of which is restricted for environmental and toxicological reasons.
This test method also describes the titration of various ratio blends of sodium alkylbenzene sulfonate and sodium xylene sulfonate. Active matter content in these blends is attributable directly to sodium alkylbenzene sulfonate. Therefore, the presence of various amounts of sodium xylene sulfonate in these blends does not interfere with the determination of percent actives.
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 sulfonic acid, alcohol sulfate, sodium 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 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
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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(Reapproved 2005)
Standard Test Method for
Determination of Various Anionic Surfactant Actives by
Potentiometric Titration
This standard is issued under the fixed designation D6173; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 active matter, n—the organic surface-active material
present in the detergent.Also defined in Terminology D459 as
1.1 Thistestmethodisbasedonapotentiometrictitrationof
active ingredient of detergents.
common anionic surfactants and blends of anionic surfactant
with a hydrotrope. This test method solely is intended for the
4. Summary of Test Method
analysis of active matter in the following surfactants: alcohol
ether sulfate, alpha olefin sulfonate, alkylbenzene sulfonic
4.1 This test method describes a potentiometric titration
acid, alcohol sulfate, sodium alkylbenzene sulfonate/sodium
procedure for determining active matter in anionic surfactant.
xylene sulfonate blend (5:1), sodium alkylbenzene sulfonate/
Theanionicsurfactantisfirstdissolvedinwater,andthepHof
sodium xylene sulfonate blend (16:1), and sodium alkylben-
the solution is adjusted according to the type of anionic
zenesulfonate/sodiumxylenesulfonateblend(22:1).Ithasnot
surfactant being measured. In the potentiometric titration the
been tested for surfactant formulations.
anionic surfactant is titrated with a standard solution of
1.2 This standard does not purport to address all the safety
Hyamineusingasurfactantelectrode,andthereactioninvolves
concerns, if any, associated with its use. It is the responsibility
the formation of a complex between the anionic surfactant and
of the user of this standard to establish appropriate safety and
the cationic titrant (Hyamine), which then precipitates. At the
health practices and determine the applicability of regulatory
end point the surfactant electrode appears to respond to an
limitations prior to use. Material Safety Data Sheets are
excess of titrant with potential change large enough to give a
available for reagents and materials. Review them for hazards
well defined inflection in the titration curve.
prior to usage.
5. Significance and Use
2. Referenced Documents
2.1 ASTM Standards:
5.1 The most common anionic surfactants presented in this
D459Terminology Relating to Soaps and Other Detergents
test method are used widely in synthetic detergents and other
D1681Test Method for SyntheticAnionicActive Ingredient
household cleaners. Current analysis of the active matter in
in Detergents by Cationic Titration Procedure
these anionic surfactants involves the two-phase aqueous/
D3049Test Method for Synthetic Anionic Ingredient by
chloroform titration with a mixed indicator, organic dyes such
Cationic Titration
as disulphine blue/dimidium bromide (see Test Method
D3049), and methylene blue (see Test Method D1681). This
3. Terminology
test method eliminates the use of hazardous chloroform, the
3.1 Definitions of Terms Specific to This Standard:
use of which is restricted for environmental and toxicological
reasons.
This test method is under the jurisdiction ofASTM Committee D12 on Soaps
and Other Detergents and is the direct responsibility of Subcommittee D12.12 on
5.2 This test method also describes the titration of various
AnalysisandSpecificationsofSoaps,Synthetics,DetergentsandtheirComponents.
ratio blends of sodium alkylbenzene sulfonate and sodium
Current edition approved May 1, 2005. Published June 2005. Originally
xylene sulfonate. Active matter content in these blends is
approved in 1997. Last previous edition approved in 1997 as D6173-97. DOI:
10.1520/D6173-97R05.
attributable directly to sodium alkylbenzene sulfonate.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Therefore, the presence of various amounts of sodium xylene
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
sulfonate in these blends does not interfere with the determi-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. nation of percent actives.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6173 − 97 (2005)
6. Apparatus 7.9 Sodium Lauryl Sulfate 0.0001 m Solution, buffered at
pH 4.00, with a graduated cylinder transfer 2 mL of sodium
6.1 Autotitration System, equipped with a delivery buret
3,4 laurylsulfate0.004Msolutiontoa150-mLbeaker.Add80mL
system, 10 or 20-mL capacity.
of deionized water and 1 mL of buffer solution pH 4.00 and
3,4
6.2 Phoenix Surfactant Combination Electrode , nitrate
mix well. This solution is use for conditioning the electrodes.
4,5
specific ion electrode, or surfactant electrode equipped with
5 7.10 Electrode Rinse Solution—Transfer approximately 50
silver/silver chloride reference electrode. The conditioning of
mLof0.1MHClsolutionto1Lvolumetricflaskanddiluteto
this type of electrode is essential for obtaining a good break in
volume.
the titration curve. Therefore, each electrode should be condi-
tioned in sodium lauryl sulfate 0.0001M solution for 15 min.
8. Preparation of Primary Standard Reagents
For other electrode requirements, follow the manufacturer’s
-3
8.1 Sodium Lauryl Sulfate Solution, 4×10 N. Weigh
instruction manual.
accurately 1.15 + 0.01 g of sodium lauryl sulfate to the nearest
6.3 Analytical Balance.
0.1 mg. Dissolve in water and dilute to a final volume of 1L.
6.4 Standard Laboratory Glassware. Calculate the normality of the solution according to the
following equation:
7. Reagents
W 3P
Normalityof SodiumLaurylSulfate 5 (1)
288.38 3100
7.1 Hyamine 1622, diisobutylphenoxyethoxyethyl dimethyl ~ !
benzyl ammonium chloride monohydrate.
where:
7.2 Potassium Chloride, reagent grade.
P = purity of the sodium lauryl sulfate, weight %, and
4,7
W = weight of sodium lauryl sulfate, g.
7.3 Triton X-100 , electrophoresis grade.
8.2 Keep the solution no longer than one month before
7.4 Potassium Chloride 4.0 M Solution—Prepare by weigh-
making a fresh solution.
ingout30.00gtothenearest0.01gofpotassiumchlorideinto
-3
a 100 mL volumetric glass and dissolving in deionized water.
8.3 Hyamine 1622 Solution,4×10 N—Dissolve 1.85 +
Dilute to the mark with deionized water.Add exactly one drop
0.5 g of Hyamine 1622 in deionized water and dilute to a final
of Triton X-100 to the solution and mix well. This is only a
volume of 1L.
reference electrode filling solution for the Phoenix electrode. -3
8.4 Hyamine 1622 Solution Standardization, 4×10
7.5 Triton X-100, 1 % Solution—Prepare by weighing 1.00
N—This determination shall be done in triplicate. Pipet 5.00
g of Triton X-100 into a 100-mLvolumetric flask and diluting
mL of the standard lauryl sulfate solution into a 150-mL
to the mark with deionized water.
beaker.Add 50 mL of dionized water, and, while stirring, add
4,8
1 mL of buffer solution pH 4 and 1 mL of Triton-X-100, 1%
7.6 Sodium Lauryl Sulfate , primary standard.
solution. To minimize noise in the titration, make sure that the
NOTE1—Sodiumlaurylsulfateshallbeanalyzedforpurityaccordingto
buret tip is placed close to the center of the stir bar. Stir
the reagent section of Test Method D3049 before its use as primary
moderately. Erroneous results can occur if excessive foaming
standard.
takes place. Titrate potentiometrically with the Hyamine 1622
4,9
7.7 Buffer Solution pH 4.00
solution and record the titration volume. The Titroprocessor
4,9
will perform the titration, determine the inflection point and
7.8 Buffer Solution pH 7.00 —Pipet 10 mL of buffer
calculate the results according to the following equation:
solution pH 7.00 and transfer to a 100-mL volumetric flask.
Dilute to volume and mix well.
N 35
NormalityofHyamine1622 5 (2)
V
where:
The sole source of supply of the autotitration system and Phoenix electrode
N = normality of sodium lauryl sulfate standard solution,
known to the committee at this time is Brinkmann Instruments, Inc. Cantiague Rd.,
5 = sodiumlaurylsulfatealiquottakenfortitration,mL,and
Westbury, NY 11590.
If you are aware of alternative suppliers, please provide this information to
V = Hyamine 1622 solution required to reach the endpoint,
ASTMheadquarters.Yourcommentswillreceivecarefulconsiderationatameeting
mL.
of the responsible technical committee, which yo
...
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