EXPLANATION
Ethanol is used as a blending agent added to gasoline. Sulfates are indicated in filter plugging deposits and fuel injector deposits. When fuel ethanol is burned, sulfates may contribute to sulfuric acid emissions. Ethanol acceptability for use depends on its sulfate content. This method is applicable to hydrous, anhydrous ethanol, and anhydrous denatured ethanol, which is added as a blending agent with spark ignition fuels. The range of determination is 1.0 to 20 mg/kg of total inorganic sulfate.
TEST SUMMARY
An ethanol sample is titrated in ethanolic medium with a standard lead nitrate solution. Lead sulfate precipitate is formed during the titration. Perchloric acid is added to remove possible interference from carbonate. The end point is signaled by an increase in lead ion activity as measured by a lead-selective electrode.
TEST PRECISION
where X is the results of two determinations.
Since there are no generally accepted reference materials for this property, bias of this method cannot be determined.