ASTM D 6839a:2021

1.1 This test method covers the quantitative determination of saturates, olefins, aromatics, and oxygenates in spark-ignition engine fuels by multidimensional gas chromatography. Each hydrocarbon type can be reported either by carbon number (see Note 1 ) or as a total. Note 1: There can be an overlap between the C 9 and C 10 aromatics; however, the total is accurate. Isopropyl benzene is resolved from the C 8 aromatics and is included with the other C 9 aromatics. 1.2 This test method is not intended to determine individual hydrocarbon components except benzene and toluene. 1.3 This test method is divided into two parts, Part A and Part B. 1.3.1 Part A is applicable to the concentration ranges for which precision (Table 10 and Table 11) has been obtained: Property Units Applicable range Total aromatics Volume % 19.32 to 46.29 Total saturates Volume % 26.85 to 79.31 Total olefins Volume % 0.40 to 26.85 Oxygenates Volume % 0.61 to 9.85 Oxygen Content Mass % 2.01 to 12.32 Benzene Volume % 0.38 to 1.98 Toluene Volume % 5.85 to 31.65 Methanol Volume % 1.05 to 16.96 Ethanol Volume % 0.50 to 17.86 MTBE Volume % 0.99 to 15.70 ETBE Volume % 0.99 to 15.49 TAME Volume % 0.99 to 5.92 TAEE Volume % 0.98 to 15.59 1.3.1.1 This test method is specifically developed for the analysis of automotive motor gasoline that contains oxygenates, but it also applies to other hydrocarbon streams having similar boiling ranges, such as naphthas and reformates. 1.3.2 Part B describes the procedure for the analysis of oxygenated groups (ethanol, methanol, ethers, C 3 to C 5 alcohols) in ethanol fuels containing an ethanol volume fraction between 50 % and 85 % (17 % to 29 % oxygen). The gasoline is diluted with an oxygenate-free component to lower the ethanol content to a value below 20 % before the analysis by GC. The diluting solvent should not be considered in the integration, this makes it possible to report the results of the undiluted sample after normalization to 100 %. 1.4 Oxygenates as specified in Test Method D4815 have been verified not to interfere with hydrocarbons. Within the round robin sample set, the following oxygenates have been tested: MTBE, ethanol, ETBE, TAME, iso -propanol, isobutanol, tert -butanol and methanol. Applicability of this test method has also been verified for the determination of n-propanol, acetone, and di -isopropyl ether (DIPE). However, no precision data have been determined for these compounds. 1.4.1 Other oxygenates can be determined and quantified using Test Method D4815 or D5599 . 1.5 The method is harmonized with ISO 22854. 1.6 This test method includes a relative bias section for U.S. EPA spark-ignition engine fuel regulations for total olefins reporting based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D1319 as a possible Test Method D6839 alternative to Test Method D1319 . The Practice D6708 derived correlation equation is only applicable for fuels in the total olefins concentration range from 0.2 % to 18.2 % by volume as measured by Test Method D6839 . The applicable Test Method D1319 range for total olefins is from 0.6 % to 20.6 % by volume as reported by Test Method D1319 . 1.7 This test method includes a relative bias section for reporting benzene based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D3606 (Procedure B) as a possible Test Method D6839 alternative to Test Method D3606 (Procedure B). The Practice D6708 derived correlation equation is only applicable for fuels in the benzene concentration range from 0.52 % to 1.67 % by volume as measured by Test Method D6839 . 1.8 This test method includes a relative bias section for reporting benzene based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D5580 as a possible Test Method D6839 alternative to Test Method D5580 . The Practice D6708 derived correlation equation is only applicable for fuels in the benzene concentration range from 0.52 % to 1.67 % by volume as measured by Test Method D6839 . 1.9 This test method includes a relative bias section for reporting benzene based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D5769 as a possible Test Method D6839 alternative to Test Method D5769 . The Practice D6708 derived correlation equation is only applicable for fuels in the benzene concentration range from 0.52 % to 1.67 % by volume as measured by Test Method D6839 . 1.10 This test method includes a relative bias section for reporting total aromatics based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D1319 as a possible Test Method D6839 alternative to Test Method D1319 . The Practice D6708 derived correlation equation is only applicable for fuels in the total aromatics concentration range from 14.3 % to 31.2 % by volume as measured by Test Method D6839 . 1.11 This test method includes a relative bias section for reporting total aromatics based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D5580 as a possible Test Method D6839 alternative to Test Method D5580 . The Practice D6708 derived correlation equation is only applicable for fuels in the total aromatics concentration range from 14.3 % to 31.2 % by volume as measured by Test Method D6839 . 1.12 This test method includes a relative bias section for reporting total aromatics based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D5769 as a possible Test Method D6839 alternative to Test Method D5769 . The Practice D6708 derived correlation equation is only applicable for fuels in the total aromatics concentration range from 14.3 % to 30.1 % by volume as measured by Test Method D6839 . 1.13 This test method includes a relative bias section for reporting total olefins based on Practice D6708 accuracy assessment between Test Method D6839 and Test Method D6550 as a possible Test Method D6839 alternative to Test Method D6550 . The Practice D6708 derived correlation equation is only applicable for fuels in the total olefins concentration range from 1.5 % to 17.2 % by volume as measured by Test Method D6839 . 1.14 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. ...

71.040.50