ASTM D1681-05(2014)
(Test Method)Standard Test Method for Synthetic Anionic Active Ingredient in Detergents by Cationic Titration Procedure (Withdrawn 2023)
Standard Test Method for Synthetic Anionic Active Ingredient in Detergents by Cationic Titration Procedure (Withdrawn 2023)
SIGNIFICANCE AND USE
4.1 This test method determines 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.
SCOPE
1.1 Direct titration of an anionic surfactant with a standardized cationic reagent is a simple and convenient method for the quantitative determination of the content of active ingredient. The end point is detffected by the transfer of a colored complex from an organic solvent phase to an aqueous phase. The relationship between anionic and cationic agents is not always stoichiometric, and for maximum accuracy the anionic type of interest should first be characterized and then used to standardize the cationic reagent. In most cases, however, the different anionic surfactants likely to be encountered react in the same proportions. That is, a cationic titrating solution standardized against a characterized anionic agent can be used to analyze other anionics of known molecular weights.
1.2 This test method is applicable to alkylaryl sulfonates and fatty alkyl sulfates. Low results are obtained with alkylbenzene sulfonates having the alkyl chain length less than eight carbon atoms. Low results are also obtained for alkyl sulfates with the alkyl chain length of less than twelve carbon atoms. The anionic surfactants characterized in accordance with Sections 17 – 23 should be the sodium salt and not amine, ammonium, or potassium salts. In case only amine or ammonium salts are available, they should be first converted to the sodium salt before proceeding with this analysis.
1.3 The analytical procedures appear in the following order:
Sections
Separation of Alcohol-Soluble Matter
8 and 9
Separation of Oil-Free Sulfonate
10 and 11
Determination of Sodium Chloride (NaCl) Content
12 – 17
Characterization of Anionic Surfactant Standard:
Part I. Determination of Surfactant, SO3 Content, and Solution
Molarity
18 – 20
Part II. Determination of Surfactant, SO3 and Active Ingredient
Contents Combining Weight, and Solution Molarity
21 – 24
Standardization of Cationic Reagent
25 – 29
Quantitative Determination of Anionic Surfactant by Cationic
Titration
30 – 33
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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. For a specific hazards statement, see Section 7.
WITHDRAWN RATIONALE
Direct titration of an anionic surfactant with a standardized cationic reagent is a simple and convenient method for the quantitative determination of the content of active ingredient. The end point is detffected by the transfer of a colored complex from an organic solvent phase to an aqueous phase. The relationship between anionic and cationic agents is not always stoichiometric, and for maximum accuracy the anionic type of interest should first be characterized and then used to standardize the cationic reagent. In most cases, however, the different anionic surfactants likely to be encountered react in the same proportions. That is, a cationic titrating solution standardized against a characterized anionic agent can be used to analyze other anionics of known molecular weights.
Formerly under the jurisdiction of Committee D12 on Soaps and Other Detergents, this practice was withdrawn in January 2023 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
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: D1681 − 05 (Reapproved 2014)
Standard Test Method for
Synthetic Anionic Active Ingredient in Detergents by
1
Cationic Titration Procedure
This standard is issued under the fixed designation D1681; 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 1.4 The values stated in SI units are to be regarded as
standard. No other units of measurement are included in this
1.1 Direct titration of an anionic surfactant with a standard-
standard.
ized cationic reagent is a simple and convenient method for the
1.5 This standard does not purport to address all of the
quantitative determination of the content of active ingredient.
safety concerns, if any, associated with its use. It is the
Theendpointisdetffectedbythetransferofacoloredcomplex
responsibility of the user of this standard to establish appro-
from an organic solvent phase to an aqueous phase. The
priate safety and health practices and determine the applica-
relationship between anionic and cationic agents is not always
bility of regulatory limitations prior to use. For a specific
stoichiometric, and for maximum accuracy the anionic type of
hazards statement, see Section 7.
interest should first be characterized and then used to standard-
ize the cationic reagent. In most cases, however, the different
2. Referenced Documents
anionic surfactants likely to be encountered react in the same
2
2.1 ASTM Standards:
proportions. That is, a cationic titrating solution standardized
D1193 Specification for Reagent Water
against a characterized anionic agent can be used to analyze
other anionics of known molecular weights.
3. Summary of Test Method
1.2 This test method is applicable to alkylaryl sulfonates
3.1 This test method involves isolating alkylaryl sulfonate
and fatty alkyl sulfates. Low results are obtained with alkyl-
orfattyalkylsulfatebyextractionwithethylalcoholtoremove
benzenesulfonateshavingthealkylchainlengthlessthaneight
inorganic salts, extracting the alcohol-soluble material with
carbon atoms. Low results are also obtained for alkyl sulfates
petroleum ether to remove unsulfonatable matter, correcting
with the alkyl chain length of less than twelve carbon atoms.
for sodium chloride present, and determining the active ingre-
The anionic surfactants characterized in accordance with
dientcombiningweight.Thecharacterizedsurfactantisusedto
Sections17–23 should be the sodium salt and not amine,
standardize a cationic reagent which in turn is used to titrate
ammonium, or potassium salts. In case only amine or ammo-
similar anionic surfactants.
nium salts are available, they should be first converted to the
sodium salt before proceeding with this analysis.
4. Significance and Use
1.3 The analytical procedures appear in the following order:
4.1 This test method determines anionic detergents com-
Sections
monly found in laundry, dishwashing, and other cleaning
Separation of Alcohol-Soluble Matter 8 and 9
materials. Accurate determination of the anionic active sub-
Separation of Oil-Free Sulfonate 10 and 11
stance is highly important in assessing the cost and effective-
Determination of Sodium Chloride (NaCl) Content 12–17
Characterization of Anionic Surfactant Standard:
ness of such cleaning substances.
Part I. Determination of Surfactant, SO Content, and Solution 18–20
3
Molarity
5. Interferences
Part II. Determination of Surfactant, SO and Active Ingredient 21–24
3
Contents Combining Weight, and Solution Molarity
5.1 With the exception of picrate, perchlorate, thiocyanate,
Standardization of Cationic Reagent 25–29
nitrate, dichromate, and chromate, common inorganic anions
Quantitative Determination of Anionic Surfactant by Cationic 30–33
and low molecular weight organic anions do not interfere with
Titration
this analysis. However, sulfonates of xylene, cunene, or tolu-
ene interfere positively. Since the cationic titration is con-
ducted under acidic conditions, soap does not interfere. Soap
1
This test method is under the jurisdiction of ASTM Committee D12 on Soaps
and Other Detergentsand is the direct responsibility of Subcommittee D12.12 on
2
Analysis and Specifications of Soaps, Synthetics, Detergents and their Components. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2014. Published February 2014. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1959. Last previous edition approved in 2005 as D1681 – 05. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1681-05R14. the ASTM website.
Copyr
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.