Translated Standard: Russian
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Significance and Use

Regulations limiting the concentration of benzene and the total aromatic content of finished gasoline have been established for 1995 and beyond in order to reduce the ozone reactivity and toxicity of automotive evaporative and exhaust emissions. Test methods to determine benzene and the aromatic content of gasoline are necessary to assess product quality and to meet new fuel regulations.

This test method can be used for gasolines that contain oxygenates (alcohols and ethers) as additives. It has been determined that the common oxygenates found in finished gasoline do not interfere with the analysis of benzene and other aromatics by this test method.

1. Scope

1.1 This test method covers the determination of benzene, toluene, ethylbenzene, the xylenes, C ₉ and heavier aromatics, and total aromatics in finished motor gasoline by gas chromatography.

1.2 The 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 C ₉ and heavier aromatics. For the C ₈ aromatics, p -xylene and m -xylene co-elute while ethylbenzene and o -xylene are separated. The C ₉ and heavier aromatics are determined as a single group.

1.3 This test method covers the following concentration ranges, in liquid volume %, for the preceding aromatics: benzene, 0.1 to 5 %; toluene, 1 to 15 %; individual C ₈ aromatics, 0.5 to 10 %; total C ₉ and heavier aromatics, 5 to 30 %, and total aromatics, 10 to 80 %.

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

1.5 Many 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.

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

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.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1298 Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method

D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter

D4057 Practice for Manual Sampling of Petroleum and Petroleum Products

D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards

E355 Practice for Gas Chromatography Terms and Relationships

Keywords

aromatics; benzene; ethylbenzene; gas chromatography; gasoline; toluene; xylenes; Aromatic compounds; Aromatic hydrocarbons (AHs); Benzene--petroleum products; Ethylbenzene; Finished motor/aviation gasoline; Gas chromatography (GC)--petroleum products; Gasoline; Toluene--petroleum products; Total aromatics; Xylene; ortho -Xylene;

ICS Code

ICS Number Code 75.160.20 (Liquid fuels)

DOI: 10.1520/D5580-02R07

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ASTM D5580