Sulfur Content
The requirements to lower the sulfur content of gasoline have led to the sulfur content of ethanol being an important issue. The ASTM has a sulfur specification for denatured ethanol in ASTM D4806 and California has its own applicable regulation regarding the sulfur content of denatured ethanol. Currently, industry consensus indicates the most appropriate ASTM test method for determining the sulfur content of ethanol to be "ASTM D5453 Standard Test Method for Determination of Total Sulfur in Light Hydrocarbons, Motor Fuels and Oils by Ultraviolet Fluorescence." This is the test method specified in California regulations. The most recent copy of ASTM D4806 should be consulted for applicable sulfur limitations and appropriate test procedures.
Small amounts of inorganic sulfates can, under some circumstances, contribute to deposits in meter and dispensing pumps as well as causing automotive fuel injectors to stick. Test methods to measure for total sulfates include ASTM D7318, ASTM D7319, and ASTM D7328.