5.1 This test method provides a method of determining the percentage of ethanol in an ethanol-gasoline fuel blend over the range of 20 to 100 mass% for compliance with fuel specifications and federal or local fuel regulations.

5.2 Ethanol content of denatured fuel ethanol for gasoline blending is required in accordance with Specification D4806.

5.3 Ethanol content of ethanol fuel blends for flexible-fuel automotive spark-ignition engines is required in accordance with Specification D5798.

1.1 This test method covers the determination of the ethanol content of hydrocarbon blends containing greater than 20% ethanol. This method is applicable to denatured fuel ethanol, ethanol fuel blends, and mid-level ethanol blends.

1.1.1 Ethanol is determined from 20 mass% to 100 mass% and methanol is determined from 0.01 mass% to 0.6 mass%. Equations used to convert these individual alcohols from mass% to volume% are provided.

1.2 This test method does not purport to identify all individual components common to ethanol production or those components that make up the denaturant or hydrocarbon constituent of the fuel.

1.3 Water cannot be determined by this test method and shall be measured by a procedure such as Test Method D1364 and the result used to correct the concentrations determined by this method.

1.4 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.

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are provided for information purposes only.

1.6 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.