ASTM D4420 Determination of Aromatics in Finished Gasoline by Gas Chromatography
3. Summary of Test Method
3.1 A two-column chromatographic system connected to a dual-filament thermal conductivity detector (or two single-filament detectors) is used. A reproducible volume of sample is injected into the column containing a polar liquid phase. The nonaromatics are directed to the reference side of the detector (or single-filament Detector B) and vented to the atmosphere as they elute. The column is backflushed immediately before the elution of benzene, and the aromatic portion is directed into the second column containing a nonpolar liquid phase. The aromatic components elute in the order of their boiling points and are detected on the analytical side of the detector (or single-filament Detector A). Immediately after the C8 aromatics have eluted, the flow through the nonpolar column is reversed to backflush the C9 and heavier aromatics from the column through the detector. Quantitative results are obtained from the measured areas of the recorded aromatic peaks by utilizing factors obtained from the analysis of a blend of known aromatic content.
4. Significance and Use
4.1 A knowledge of aromatics in gasolines is helpful in assessing product quality. Such knowledge can also be an aid in evaluating the health hazard to persons handling and using gasoline.
