ASTM D5501 Standard Test Method for Determination of Ethanol Content of Denatured Fuel Ethanol by Gas Chromatography
4. Summary of Test Method
4.1 A representative aliquot of the fuel ethanol sample is introduced into a gas chromatograph equipped with a polydimethylsilicoxane bonded phase fused silica capillary column. Helium carrier gas transports the vaporized aliquot through the column where the components are separated by the chromatographic process. Components are sensed by a flame ionization detector as they elute from the column. The detector signal is processed by an electronic data acquisition system. The ethanol and methanol components are identified by comparing their retention times to the ones identified by analyzing standards under identical conditions. The concentrations of all components are determined in mass percent area by normalization of the peak areas.
5. Significance and Use
5.1 Fuel ethanol is required to be denatured with gasoline in accordance with Specification D4806. 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.
