ASTM D3339-12(2017)

1.1 This test method covers the determination of acidic constituents in new or used petroleum products and lubricants soluble or nearly soluble in mixtures of toluene, and isopropyl alcohol. The test method is especially intended for cases in which the amount of sample available to be analyzed is too small to allow accurate analysis by Test Methods D974 or D664. It is applicable for the determination of acids having dissociation constants in water larger than 10⁻⁹. Extremely weak acids having dissociation constants smaller than 10⁻⁹ do not interfere. Salts titrate if their hydrolysis constants are larger than 10⁻⁹.