ASTM D6293-98(2003)e1

A knowledge of spark-ignition engine fuel composition is useful for regulatory compliance, process control, and quality assurance.

The quantitative determination of olefins and other hydrocarbon types in spark-ignition engine fuels is required to comply with government regulations.

This test method is not applicable to M85 and E85 fuels, which contain 85 % methanol and ethanol, respectively.

1.1 This test method provides for the quantitative determination of oxygenates, paraffins, olefins, naphthenes, and aromatics in low-olefin spark-ignition engine fuels by multidimensional gas chromatography. Each hydrocarbon type can be reported either by carbon number (see ) or as a total through C10, except for olefins, which can only be reported through C9. Higher boiling hydrocarbons cannot be reported by type and are reported as a composite group. The lower limit of detection for a single hydrocarbon component or carbon number type is 0.05 mass %.

Note 1—There can be an overlap between the C9 and C10 aromatics; however, the total is accurate. Isopropyl benzene is resolved from the C8 aromatics and is included with the other C9 aromatics. Naphthalene is determined with the C11+ components.

1.2 This test method is applicable for total olefins in the range from 0.05 to 13 mass %. The test method can quantitatively determine olefins in samples where the olefin concentration does not exceed 0.6 % C4 or 4.0 % C5 or 4.5 % of the combined C4 and C5. Although the precision for benzene was determined in the range from 0.3 to 1.0 mass %, this test method can be used to determine benzene concentrations up to 5.0 mass %.

1.3 This test method is not intended to determine individual hydrocarbon components except for those hydrocarbon types for which there is only one component within a carbon number. Individually determined hydrocarbons are benzene, toluene, cyclopentane, propane, propylene, and cyclopentene.

1.4 Precision data has only been obtained on samples containing MTBE. Application of this test method to determine other oxygenates shall be verified in the user's laboratory. Methanol cannot be determined and shall be quantitated by an appropriate oxygenate method such as Test Method D 4815 or D 5599. Methanol is fully resolved and does not interfere with the determination of other components or groups.

1.5 Although specifically written for spark-ignition engine fuels containing oxygenates, this test method can also be applied to other hydrocarbon streams having similar boiling ranges, such as naphthas and reformates.

1.6 The values stated in SI units are to be regarded as the 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.