ASTM D2358-16

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Designation: D2358 − 89 (Reapproved 2009) D2358 − 16
Standard Test Method for
Separation of Active Ingredient from Surfactant and Syndet
Compositions
This standard is issued under the fixed designation D2358; 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
1.1 This test method covers the procedure for the separation and purification of active ingredient from surfactants and syndet
compositions. The separated active ingredient may be used for qualitative examinations. This test method also permits the
estimation of total active ingredient level present in the sample under test.
1.2 This test method yields the active ingredient together with other alcohol-soluble materials and therefore is useful only in
estimating the actual active ingredient level. Correction for the amount of the most common contaminant, sodium chloride, is
shown by a separate determination.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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. Material Safety Data Sheets are available for reagents and materials. Review them for hazards prior to
usage.
2. Referenced Documents
2.1 ASTM Standards:
D1681 Test Method for Synthetic Anionic Active Ingredient in Detergents by Cationic Titration Procedure
3. Summary of Test Method
3.1 The test method involves the extraction of the active ingredient with alcohol. Reprecipitation of the insolubles is specified
to remove the last traces of active ingredient. Dilution of the alcoholic extract to a known volume and the evaporation of a suitable
aliquot permits measurement of total alcohol-soluble matter. An estimation of sodium chloride content is made so that a corrected
total active ingredient level may be obtained. Provision is made for purification of the active ingredients in Section 1413.
3.2 Purity of Reagents:
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
and Specifications of Soaps, Synthetics, Detergents and their Components.
Current edition approved Oct. 1, 2009July 1, 2016. Published December 2009August 2016. Originally approved in 1965 as D2358 – 65 T. Last previous edition approved
in 20032009 as D2358 – 89 (2003).89 (2009). DOI: 10.1520/D2358-89R09.10.1520/D2358-16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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D2358 − 16
3.2.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform
to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are
available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use
without lessening the accuracy of the determination.
3.3 Unless otherwise indicated, references to water shall be understood to mean distilled water or water of equal purity.
4. Reagents
4.1 Purity of Reagents:
4.1.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform
to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are
available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use
without lessening the accuracy of the determination.
4.2 Unless otherwise indicated, references to water shall be understood to mean distilled water or water of equal purity.
SEPARATION OF TOTAL ALCOHOL-SOLUBLE MATTER
SEPARATION OF TOTAL ALCOHOL-SOLUBLE MATTER
4. Reagents
4.1 Ethyl Alcohol (95 percent)—Freshly boiled ethyl alcohol conforming to Formula No. 3A or No. 30 of the U. S. Bureau of
Internal Revenue. The alcohol should not be neutralized. Redistilled alcohol shall be used if alkali absorption is more than 0.2 mL
of 0.1 N NaOH solution/100 mL of alcohol.
4.2 Ethyl Alcohol (Absolute)—Freshly boiled 200-proof ethyl alcohol conforming to either Formulas No. 3A or No. 30 of the
U. S. Bureau of Internal Revenue.
4.3 Phenolphthalein Indicator Solution (10 g/L)—Dissolve 1 g of phenolphthalein in 50 mL of ethyl alcohol (95 %) and then
mix with 50 mL of water.
4.4 Sulfuric Acid (1 + 100)—Add 1 mL of concentrated sulfuric acid (H SO , sp gr 1.84) to 100 mL of water.
2 4
5. Safety Precautions
5.1 Formulas No. 3A and No. 30 ethyl alcohols are denatured alcohols. They are health hazards and flammable liquids. See
manufacturer’s label warning as to use, safe handling, and disposal.
5.2 Sulfuric acid is corrosive. Use proper protective equipment including adequate eye protection. If acid contacts the body or
is splashed in the eyes, flush the affected parts with water for at least 15 min. Obtain medical attention.
6. Procedure
6.1 Weigh out a sample, to the nearest 0.01 g, to correspond with the levels of active ingredient prescribed in Table 1 and
transfer to a 600-mL beaker. Liquid samples containing high levels of water should be evaporated to a pasty consistency after
weighing. Samples containing high levels of hydrated alkaline salts should be dried in an oven at 105°C for 1 h after weighing.
6.2 Add 300 to 350 mL of hot 95 % alcohol. Cover with a watch glass and heat on a steam bath for approximately 1 ⁄2 to 2 h,
stirring frequently to disperse the solids and break up any lumps.
6.3 Remove the beaker from the steam bath and permit the insolubles to settle for a few minutes. Add 2 drops of phenolphthalein
indicator solution. If the solution is pink, neutralize with 1 N H SO using no more than 1 mL. Samples containing high levels
...