Fuel ethanol is required to be denatured with gasoline in accordance with Specification D 4806. State and federal laws specify the concentration of ethanol in gasoline blends. The determination of the amount of denaturant is important to ensure the blended fuel complies with federal and state laws. This test method provides a method of determining the percentage of ethanol (purity) of the fuel ethanol that is blended into gasoline.

1.1 This test method covers the determination of the ethanol content of denatured fuel ethanol by gas chromatography.

1.2 Ethanol is determined from 93 to 97 mass % and methanol is determined from 0.01 to 0.6 mass %. Equations used to convert these individual alcohols from mass % to volume % are provided.

1.3 This test method does identify and quantify methanol but does not purport to identify all individual components that make up the denaturant.

1.4 Water cannot be determined by this test method and shall be measured by a procedure such as Test Method D 1364 and the result used to correct the chromatographic values.

1.5 This test method is inappropriate for impurities that boil at temperatures higher than 225°C or for impurities that cause poor or no response in a flame ionization detector, such as water.

1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.