ASTM D3341 Test Method for Lead in Gasoline-Iodine Monochloride Method
3. Summary of Test Method
3.1 A known volume of the sample is diluted with heavy distillate and shaken with aqueous iodine monochloride reagent. Any tetraalkyl lead compounds present react with the iodine monochloride and are extracted into the aqueous phase as the dialkyl lead compounds. The aqueous extract is separated from the gasoline and evaporated to low bulk to decompose free iodine monochloride. Any organic matter present is removed by oxidation with nitric acid, which also serves to convert the dialkyl lead compounds into inorganic lead compounds. The residue is dissolved in distilled water and buffered to pH 5 using sodium acetate-acetic acid buffer. The lead content of the buffered solution is determined by titration with EDTA using xylenol orange as indicator.
4. Significance and Use
4.1 This test method determines the concentration of lead alkyl additives in gasoline. These additives improve the antiknock properties.
