1.1This test method covers the determination of benzene, toluene, ethylbenzene, the xylenes, C₉ and heavier aromatics, and total aromatics in finished motor gasoline by gas chromatography.

1.2The aromatic hydrocarbons are separated without interferences from other hydrocarbons in finished gasoline. Nonaromatic hydrocarbons having a boiling point greater than n-dodecane may cause interferences with the determination of the C₉ and heavier aromatics. For the C₈ aromatics, p-xylene and m-xylene co-elute while ethylbenzene and o-xylene are separated. The C₉ and heavier aromatics are determined as a single group.

1.3This test method covers the following concentration ranges, in liquid volume %, for the preceding aromatics: benzene, 0.1 to 5 %; toluene, 1 to 15 %; individual C₈ aromatics, 0.5 to 10 %; total C₉ and heavier aromatics, 5 to 30 %, and total aromatics, 10 to 80 %.

1.4Results are reported to the nearest 0.01 % by either mass or by liquid volume.

1.5This test method includes a relative bias section for U.S. EPA spark-ignition engine fuel regulations reporting for benzene based on Practice D6708 accuracy assessment between Test Method D5580 and Test Method D3606 as a possible Test Method D5580 alternative to Test Method D3606. The Practice D6708 derived correlation equation is only applicable for fuels in the benzene concentration range from 0.0 % to 2.31 % by volume as measured by Test Method D5580. The applicable Test Method D3606 range for benzene is from 0.0 % to 2.38 % by volume as reported by Test Method D3606.

1.6This test method includes a relative bias section for U.S. EPA spark-ignition engine fuel regulations for total aromatics reporting based on Practice D6708 accuracy assessment between Test Method D5580 and Test Method D5769 as a possible Test Method D5580 alternative to Test Method D5769. The Practice D6708 derived correlation equation(s) is only applicable for fuels in the total aromatic concentration range from 5.4 % to 31.6 % by volume as measured by Test Method D5580 and a distillation temperature T₉₅, at which 95 % of the sample has evaporated, as measured by Test Method D86 is in the range of 149.1 °C to 196.6 °C (300.4 °F to 385.9 °F).

1.7Many of the common alcohols and ethers that are added to gasoline to reduce carbon monoxide emissions and increase octane, do not interfere with the analysis. Ethers such as methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), and diisopropylether (DIPE) have been found to elute from the precolumn with the nonaromatic hydrocarbons to vent. Other oxygenates, including methanol and ethanol elute before benzene and the aromatic hydrocarbons. 1-Methylcyclopentene has also been found to elute from the precolumn to vent and does not interfere with benzene.

1.8The values stated in SI units are to be regarded as standard.

1.9This 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.