Designation: D5352 − 95 (Reapproved 2026)Standard Test Method forDetermination of Organically Combined Sulfuric AnhydrideAsh-Gravimetric, Test Method C 1This standard is issued under the f i xed designation D5352; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the organi-cally combined sulfuric anhydride existing in a sample ofsulfonated or sulfated oil, or both, by extracting the undecom-posed sulfonated or sulfated fat and other fatty matter over anacidulated, concentrated salt solution, and ashing the purif i edextract. This test method is applicable to all types of sulfonatedand sulfated oils, including true sulfonic acid oils and thosecontaining sodium acetate or similar partially titratable com-pounds. This test method was derived from Test MethodsD500, Sections 25 through 28.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards: 2D500 Test Methods of Chemical Analysis of Sulfonated andSulfated Oils3. Signif i cance and Use3.1 This test method is intended for the determination oforganically combined sulfuric anhydride in sulfonated andsulfated fats and oils.4. Reagents4.1 Ethyl Ether.4.2 Hydrogen Peroxide (30 %)—Concentrated hydrogenperoxide (H 2 O 2 ).4.3 Methyl Orange Indicator Solution (1 g/L)—Dissolve0.1 g of methyl orange in 100 mL of water.4.4 Sodium Chloride (NaCl), solid.4.5 Sodium Sulfate (Na 2 SO 4 ), anhydrous.5. Procedure5.1 The procedure consists of isolating and purifying thefatty matter as it exists in the original oil by dissolving thesample in a solvent, acidifying and washing with saturatedbrine, and ashing the purif i ed extract. If the sample containsammonia, the ammonia shall f i rst be expelled before thedetermination is made on the sample.5.1.1 In the Absence of Ammonia—Proceed as described inthe separation of purif i ed oil (6.1.1 Method B), combining theether layers in the f i rst funnel rather than in the decompositionf l ask. Carefully remove any water that may settle and dehy-drate the ether layer as follows: add 5 g of anhydrous Na 2 SO 4 ,shake vigorously for 5 min, and f i lter directly into a 150 mLbeaker placed in a bath of warm water. Wash the f l ask and f i lterwith ether until free from fat (absence of oil stains on the f i lterpaper after drying) and add the f i ltrate to the beaker. To avoidcreeping of the oil, the volume in the beaker should at no timeduring the f i ltering and washing exceed 50 mL (one third full).Evaporate the ether solution until the volume has been reducedto about 20 mL and transfer the residue to a tared 50 mLcrucible (high form). Immerse the crucible in a 100 mL beakercontaining warm water until practically all of the ether hasevaporated. Rinse the beaker with two 10 mL and three 5 mLportions of ether, or until all of the oil has been transferred tothe crucible; allow each portion of rinsing ether to evaporatebefore the next rinsing is made. Burn gently the solvent-freeresidue, and f i nally ignite at a dull red heat to constant weight.1 This test method is under the jurisdiction of ASTM Committee D31 on Leatherand is the direct responsibility of Subcommittee D31.08 on Fats and OilsThis testmethod was developed in cooperation with the American Leather Chemists Assn.(Method H 44-1957).Current edition approved July 1, 2026. Published July 2026. Originally approvedin 1993. Last previous edition approved in 2019 as D5352 – 95 (2019). DOI:10.1520/D5352-95R26.2 For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at www.astm.org/contact. For Annual Book ofASTM Standards volume information, refer to the standard’s Document Summarypage on the ASTM website.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1
