ASTM D5351-93(2017)

1.1 This test method covers the determination of the organically combined sulfuric anhydride existing in a sample of sulfated oil by extracting the undecomposed sulfated fat and other fatty matter over an acidulated, concentrated salt solution, boiling the residue with sulfuric acid after evaporating the solvent, and titrating the products of reaction. This test method is applicable only to sulfated oils that split off their combined SO₃ upon boiling with mineral acids, including samples containing sodium acetate or other compounds that cannot be accurately titrated in water solution with methyl orange as the indicator. This test method was derived from Test Methods D500, Sections 20 through 24, and ALCA Method H-43.