ASTM D6839-21a

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6839 − 21 D6839 − 21a
Standard Test Method for
Hydrocarbon Types, Oxygenated Compounds, Benzene, and
BenzeneToluene in Spark Ignition Engine Fuels by
Multidimensional Gas Chromatography
This standard is issued under the fixed designation D6839; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
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 and C aromatics; however, the total is accurate. Isopropyl benzene is resolved from the C aromatics
9 10 8
and is included with the other C aromatics.
1.2 This test method is not intended to determine individual hydrocarbon components except benzene.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 automotive motor gasolinethe concentration ranges for which precision (Table 9) (Table 10 and Table
11) has been obtained 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
for total volume fraction of aromatics of up to 50 %; a total volume fraction of olefins from about 1.5 % up to 30 %; a
volume fraction of oxygenates, from 0.8 % up to 15 %; a total mass fraction of oxygen from about 1.5 % to about 3.7 %; and
a volume fraction of benzene of up to 2 %. Although this test method can be used to determine higher-olefin contents of up to
50 % volume fraction, the precision for olefins was tested only in the range from about 1.5 % volume fraction to about 30 %
volume fraction. The method has also been tested for an ether content up to 22 % volume fraction but no precision data has
been determined.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0L on Gas Chromatography Methods.
Current edition approved April 1, 2021May 1, 2021. Published July 2021. Originally approved in 2002. Last previous edition approved in 20182021 as
D6839 – 18.D6839 – 21. DOI: 10.1520/D6839-21.10.1520/D6839-21A.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6839 − 21a
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 to C alcohols) in ethanol
3 5
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. The derived precision data for methanol do not comply with the precision calculation as presented in this International
Standard. 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.
D6839 − 21a
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.
1.15 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.16 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator Adsorption
D3606 Test Method for Determination of Benzene and Toluene in Spark Ignition Fuels by Gas Chromatography
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D4815 Test Method for Determination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C to C Alcohols in
1 4
Gasoline by Gas Chromatography
D5580 Test Method for Determination of Benzene, Toluene, Ethylbenzene, p/m-Xylene, o-Xylene, C and Heavier Aromatics,
and Total Aromatics in Finished Gasoline by Gas Chromatography
D5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective Flame
Ionization Detection
D5769 Test Method for Determination of Benzene, Toluene, and Total Aromatics in Finished Gasolines by Gas
Chromatography/Mass Spectrometry
D6550 Test Method for Determination of Olefin Content of Gasolines by Supercritical-Fluid Chromatography
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
2.2 Other Documents:
ISO 4259 Petroleum products—Determination and application of precision data in relation to methods of test
ISO 22854 Liquid petroleum products—Determination of hydrocarbon types and oxygenates in automotive-motor gasoline—
Multidimensional gas chromatography method
3. Terminology
3.1 Definitions:
3.1.1 oxygenate, n—an oxygen-containing organic compound, which may be used as a fuel or fuel supplement, for example,
various alcohols and ethers.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 hydrogenation, n—the process of adding hydrogen to olefin molecules as a result of a catalytic reaction.
3.2.1.1 Discussion—
Hydrogenation is accomplished when olefins in the sample contact platinum at a temperature of 180 °C in the presence of
hydrogen. The olefins are converted into hydrogen saturated compounds of the same carbon number and structure. Monoolefins
and diolefins convert to paraffins while cycloolefins and cyclodienes convert to cycloparaffins.
3.2.2 trap, n—a device utilized to selectively retain specific portions (individual or groups of hydrocarbons or oxygenates) of the
test sample and to release the retained components by changing the trap temperature.
3.3 Acronyms:
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volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
D6839 − 21a
3.3.1 ETBE—ethyl-tert-butylether
3.3.2 MTBE—methyl-tert-butylether
3.3.3 TAME—tert-amyl-methylether
3.3.4 DIPE—di-isopropylether
4. Summary of Test Method
4.1 A representative sample is introduced into a computer controlled gas chromatographic system consisting of switching valves,
columns, and an olefin hydrogenation catalyst, all operating at various temperatures. The valves are actuated at predetermined
times to direct portions of the sample to appropriate columns and traps. As the analysis proceeds, the columns separate these
sample portions sequentially into groups of different hydrocarbon types that elute to a flame ionization detector.
4.2 The mass concentration of each detected compound or hydrocarbon group is determined by the application of response factors
to the areas of the detected peaks followed by normalization to 100 %. For samples containing methanol or other oxygenates that
cannot be determined by this test method, the hydrocarbon results are normalized to 100 % minus the value of the oxygenates as
determined by another test method such as Test Method D4815 or D5599.
4.3 The liquid volume concentration of each detected compound or hydrocarbon group is determined by application of density
factors to the calculated mass concentration of the detected peaks followed by normalization to 100 %.
5. Significance and Use
5.1 A knowledge of spark-ignition engine fuel composition is useful for regulatory compliance, process control, and quality
assurance.
5.2 The quantitative determination of olefins and other hydrocarbon types in spark-ignition engine fuels is required to comply with
government regulations.
5.3 This test method is not applicable to M85 fuels, which contain 85 % methanol.
6. Interferences
6.1 Some types of sulfur-containing compounds are irreversibly adsorbed in the olefin trap reducing its capacity to retain olefins.
Sulfur containing compounds are also adsorbed in the alcohol and ether-alcohol-aromatic (EAA) traps. However, a variety of
spark-ignition engine fuels have been analyzed without significant performance deterioration of these traps.
6.2 Commercial dyes used to distinguish between grades and types of spark-ignition engine fuels have been found not to interfere
with this test method.
6.3 Commercial detergent additives utilized in spark-ignition engine fuels have been found not to interfere with this test method.
6.4 Dissolved water in spark-ignition engine fuels has been found not to interfere with this test method.
7. Apparatus
7.1 The complete system that was used to obtain the precision data shown in Section 14 is comprised of a computer controlled
gas chromatograph, automated sample injector, and specific hardware modifications. These modifications include columns, traps,
a hydrogenator, and valves, which are described in 7.7 and in Section 8. Fig. 1 illustrates a typical instrument configuration (see
Note 4). Other configurations, components, or conditions may be utilized provided they are capable of achieving the required
component separations and produce a precision that is equivalent to, or better than, that shown in the precision tables.
D6839 − 21a
FIG. 1 Typical Instrument Configuration
7.2 Gas Chromatograph, capable of temperature programmed operation at specified temperatures, equipped with a heated flash
vaporization inlet, a flame ionization detector, necessary flow controllers, and computer control.
7.3 Sample Introduction System, using an automatic liquid injector, the injection volume shall be chosen in a way such that the
capacity of the column is not exceeded and that the linearity of the detector is valid.
7.3.1 An injection volume of 0.1 μL has been found satisfactory.
7.4 Gas Flow and Pressure Controllers, with adequate precision to provide reproducible flow and pressure of the carrier gas to
the chromatographic system, hydrogen for the hydrogenator, and hydrogen and air for the flame ionization detector. Control of air
flow for cooling specific system components and for automated valve operation is also required.
7.5 Electronic Data Acquisition System, shall meet or exceed the following specifications (see Note 2):
7.5.1 Capacity for 150 peaks for each analysis.
7.5.2 Normalized area percent calculation with response factors.
7.5.2.1 Area summation of peaks that are split or of groups of components that elute at specific retention times.
7.5.3 Noise and spike rejection capability.
D6839 − 21a
TABLE 1 Temperature Control Ranges of System Components
Typical
Maximum Maximum
Operating
Component Heating Cooling
Temperature
Time, min Time, min
Range, °C
Alcohol trap 60–280 2 5
Polar column 130 isothermal
Non-polar column 130 isothermal
Olefin trap 120–280 1 5
Molsieve 13X column 90–430 Temperature
programmed, ~10°/min
Ether-alcohol-aromatic 70–280 1 5
(EAA) trap
Hydrogenation catalyst 180 isothermal
Column switching valves 130 isothermal
Sample lines 130 isothermal
7.5.4 Sampling rate for fast (<0.5 s) peaks (>20 Hz to give 10 points across peak).
7.5.5 Peak width detection for narrow and broad peaks.
7.5.6 Perpendicular drop and tangent skimming, as required.
NOTE 2—Standard supplied software is typically satisfactory.
7.6 Temperature Controllers of System Components—The independent temperature control of numerous columns and traps, the
hydrogenation catalyst, column switching valves, and sample lines is required. All of the system components that contact the
sample shall be heated to a temperature that will prevent condensation of any sample component. Table 1 lists the system
components and operating temperatures (see 7.6.1). Some of the components require isothermal operation, some require rapid
heating and cooling, while one requires reproducible temperature programming. The indicated temperatures are typical; however,
the control systems utilized shall have the capability of operating at temperatures 620 °C of those indicated to accommodate
specific systems. Temperature control may be by any means that will meet the requirements listed in Table 1.
7.6.1 The system components and temperatures listed in Any column and trap Table 1 and Section 8 are specific to the analyzer
used to obtain the precision data shown in Section 14. Other columns and traps that can adequately perform the required
separations are also satisfactory but may require different temperatures.is satisfactory. Test temperatures may differ between
analyzers.
7.7 Valves, Column and Trap Switching—Suitable automated switching valves are recommended. The valves shall be intended for
gas chromatographic usage and meet the following requirements:
7.7.1 The valves must be capable of continuous operation at operating temperatures that will prevent sample condensation.
7.7.2 The valves shall be constructed of materials that are nonreactive with the sample under analysis conditions. Stainless steel,
PFA, and Vespel are satisfactory.
7.7.3 The valves shall have a small internal volume but offer little restriction to carrier gas flow under analysis conditions.
7.7.4 New valves, tubing, catalyst, columns, traps, and other materials that contact the sample or gasses may require conditioning
prior to operation in accordance with the manufacturer’s recommendations.
7.8 Gas Purifiers, to remove moisture and oxygen from helium, moisture and hydrocarbons from hydrogen, and moisture and
hydrocarbons from air.
PFA and Vespel are trademarks of E. I. DuPont de Nemours and Co.
D6839 − 21a
8. Reagents and Materials
8.1 Air, compressed, <10 mg/kg each of total hydrocarbons and H O. (Warning—Compressed gas under high pressure that
supports combustion.)
8.2 Carrier Gas, Helium or Nitrogen, 99.999 % pure, <0.1 mg ⁄kg H O. (Warning—Compressed gas under high pressure.)
NOTE 3—The system’s operating parameters such as column & trap temperatures, carrier gas flows and valve switching times are depending on the type
of carrier gas used. The use of nitrogen as carrier gas may not be possible on all configurations. Contact the equipment manufacturer for specific
information or instructions on the use of nitrogen.
8.3 Hydrogen, 99.999 % pure, <0.1 mg/kg H O. (Warning—Extremely flammable gas under high pressure.)
8.4 Columns, Traps, and Hydrogenation Catalyst (System Components)—Suitable columns and traps for reversible absorption of
certain selected chemical groups must be used (an example is given in Table 1, see also 7.6.1). Each system component is
independently temperature controlled as described in 7.6 and Table 1. Refer to Fig. 1 for the location of the components in the
system (see Note 4). The following list of components contains guidelines that are to be used to judge suitability. The guidelines
describe temperatures and times as used in a typical system. Alternatives can be used provided that the separation as described is
obtained and the separation characteristics of the entire system are not limited.
NOTE 4—Fig. 1 shows an additional trap, Molsieve 5A, and rotary valve V4 that are not required for this test method. They are included in Fig. 1 because
they were present in the instrumentation used to generate the precision data. They can be used for more detailed analyses outside the scope of this test
method, where an iso-normal paraffin, iso-normal olefin determination is desired. There is no statistical data included in this test method relating to their
use.
8.4.1 Alcohol Trap—Within a temperature range from 140 °C to 160 °C, this trap must elute benzene, toluene, all paraffins, olefins,
naphthenes, and ethers within the first 2 min after sample injection while retaining C + aromatics, all alcohols, and any other
sample components.
8.4.1.1 At a temperature of 280 °C, all retained components from 8.4.1 shall elute within 2 min of when the trap is backflushed.
8.4.2 Polar Column—At a temperature of 130 °C, this column must retain all aromatic components in the sample longer than the
time required to elute all non-aromatic components boiling below 185 °C, within the first 5 min after sample injection.
8.4.2.1 The column shall elute benzene, toluene, and all non-aromatic components with a boiling point below 215 °C within 10
min of the introduction of these compounds into the column.
8.4.2.2 This column shall elute all retained aromatic components from 8.4.2 within 10 min of when this column is backflushed.
8.4.3 Non-Polar Column—At a temperature of 130 °C, this column shall elute and separate aromatics by carbon number boiling
below 200 °C. Higher boiling paraffins, naphthenes, and aromatics are backflushed.
8.4.4 Olefin Trap—Within a temperature range from 90 °C to 105 °C, this trap shall retain (trap) all olefins in the sample for at
least 6.5 min and elute all non-olefinic components up to C in less than 6.5 min after the sample is injected. Non-olefinic
components C and higher shall be retained during this time.
8.4.4.1 Within a temperature range from 140 °C to 150 °C this trap shall retain C and higher olefins and elute all non-olefinic
components in 3 min. Olefins up to C may or may not elute in this time.
8.4.4.2 At a temperature of 280 °C, this trap shall quantitatively elute all retained olefins.
8.4.5 Molsieve 13X Column—This column shall separate paraffin and naphthene hydrocarbons by carbon number when
temperature programmed from 90 °C to 430 °C at approximately 10 ° ⁄min.
8.4.6 Porapak Column—At a temperature from 130 °C to 140 °C, this column shall separate individual oxygenates, benzene, and
toluene.
D6839 − 21a
TABLE 2 System Validation Test Mixture
Approximate Approximate
Component Concentration Concentration Warning
Mass, % Volume, %
A
Cyclopentane 1.1 1.1
A
Pentane 1.1 1.4
A
Cyclohexane 2.1 2.1
A
2,3-Dimethylbutane 2.1 2.5
A
Hexane 2.1 2.5
A
1-Hexene 1.5 1.7
A
Methylcyclohexane 4.0 4.1
A
4-Methyl-1-hexene 1.6 1.8
B
Heptane 3.5 4.0
A
1- cis-2-Dimethylcyclohexane 5.0 5.0
A
1-cis-2-Dimethylcyclohexane 5.0 5.0
B
2,2,4-Trimethylpentane 5.0 5.5
B
Octane 5.0 5.5
B
1- cis-2- cis-4-Trimethylcyclohexane 4.0 4.0
B
1-cis-2-cis-4-Trimethylcyclohexane 4.0 4.0
B
Nonane 4.5 4.9
B
Decane 4.5 4.8
B
Undecane 3.5 3.7
B
Dodecane 3.5 3.7
B
Benzene 2.2 1.9
B
Methylbenzene (Toluene) 2.2 2.0
B
trans-Decahydronaphthalene (Decalin) 4.0 3.5
B
Tetradecane 4.5 4.7
A
Ethylbenzene 4.5 4.0
A
1,2-Dimethylbenzene (o-Xylene) 4.0 3.6
A
Propylbenzene 5.0 4.5
A
1,2,4-Trimethylbenzene 4.5 4.0
A
1,2,3-Trimethylbenzene 5.0 4.5
B
1,2,4,5-Tetramethylbenzene 5.0 4.5
C
Pentamethylbenzene 5.0 4.5
Group Totals
Total Aromatics 37.4 33.5
Total Olefins 3.1 3.5
Total Saturates 59.5 63.0
Benzene 2.20 1.90
A
(Warning—Extremely flammable. Harmful if inhaled.)
B
(Warning—Flammable. Harmful if inhaled.)
C
(Warning—Harmful if inhaled.)
NOTE 5—The use of a Porapak column is not required in all configurations. For more information on a specific system, contact the equipment
manufacturer.
8.4.7 Ether-Alcohol-Aromatic (EAA) Trap—Within a temperature range from 105 °C to 130 °C, this trap shall retain all of the
ethers in the sample and elute all non-aromatic hydrocarbons boiling below 175 °C within the first 6 min after sample injection.
8.4.7.1 At a temperature of 280 °C, this trap shall elute all retained components.
8.4.8 Hydrogenation Catalyst, platinum. At a temperature of 180 °C and an auxiliary hydrogen flow of 14 mL ⁄min 6 2 mL ⁄min,
this catalyst shall quantitatively hydrogenate all olefins to paraffinic compounds of the same structure without cracking.
8.5 Test Mixture—A quantitative synthetic mixture of pure hydrocarbons is required to verify that all instrument components,
temperatures, and cut times are satisfactory to produce accurate analyses and to aid in making operating adjustments as columns
and traps age. The mixture may be purchased or prepared according to Practice D4307. Each component used in the test mixture
preparations shall have a minimum purity of 99 %. The actual concentration levels are not critical but shall be accurately known.
8.5.1 System Validation Test Mixture, used to monitor and make adjustments to the total operation of the system. The composition
and approximate component concentrations are shown in Table 2.
8.6 Quality Control Sample, used to routinely monitor the operation of the chromatographic system and verify that reported
concentrations are within the precision of the test method. Depending on the range and composition of the samples to be analyzed,
more than one quality control sample may be necessary. Any sample that is similar in composition to samples typically analyzed
D6839 − 21a
TABLE 3 Typical Gas Flow Rates
Gas Flow Rate
He (Flow A) 22 ± 2 mL/min
He (Flow B) 12 ± 1 mL/min
H (hydrogenator) 14 ± 2 mL/min
H (FID) 30–35 mL/min
Air (FID) 400–450 mL/min
may be designated as the quality control (QC) sample. The QC sample shall be of sufficient volume to provide an ample supply
for the intended period of use and it shall be homogeneous and stable under the anticipated storage conditions.
8.6.1 The quality control sample should have similar composition and hydrocarbon distribution as the sample with highest olefin
concentration routinely analyzed.
8.6.2 The quality control sample should contain oxygenates as analyzed in routine samples. Separate standards could be used for
different oxygenates.
8.6.2.1 In the event that samples containing TAME or ethanol need to be analyzed, it is best to use separate standards since optimal
separation of these components requires different alcohol trap temperature conditions.
8.7 Diluting solvent, used in Part B, should not be interfering with any other component in gasoline being analyzed. Dodecane
(C H ) or tridecane (C H ) are recommended solvents.
12 26 13 28
9. Preparation of Apparatus
9.1 Assemble the analyzer system (gas chromatograph with independent temperature controlled components) as shown in Fig. 1
or with a similar flow system. If using a commercial system, install and place the system in service in accordance with the
manufacturer’s instructions.
9.2 Impurities in the carrier gas, hydrogen, or air will have a detrimental effect on the performance of the columns and traps.
Therefore, it is important to install efficient gas purifiers in the gas lines as close to the system as possible and to use good quality
gases. The carrier gas and hydrogen gas connection lines shall be made of metal. Check that all gas connections, both exterior and
interior to the system, are leak tight.
9.3 The gas flow rates on commercial instruments are normally set prior to shipment and normally require little adjustment.
Optimize flow rates on other systems to achieve the required separations. Typical flow rates for the commercial instrument used
in the precision study are given in Table 3; however, the flows can differ somewhat from system to system.
9.3.1 Set air flow rates for column/trap cooling and for operation of air actuated valves, if required.
9.4 System Conditioning—When gas connections have been disconnected or the flow turned off, as on initial start up, condition
the system by permitting carrier gas to flow through the system for at least 30 min while the system is at ambient temperature.
After the system has been conditioned, analyze the system validation test mixture, as described in Section 11, discarding the results.
10. Standardization
10.1 The elution of components from the columns and traps depends on the applied temperatures. The switching valves also need
to be actuated at exact times to make separations of compounds into groups, for example, to retain specific compounds in a column
or trap while permitting other compounds to elute. Therefore, the separation temperatures of the columns/traps and the valve timing
are critical for correct operation of the system. These parameters need to be verified on the start up of a new system (see Note 6)
for correctness. They also require evaluation and adjustment as necessary on a regular basis to correct for changes to columns and
traps as a result of aging. To do this, the analyst shall analyze several test mixtures and make changes, as required, based on an
evaluation of the resulting chromatograms and test reports.
10.2 Using the procedure outlined in Section 11, analyze the system validation test mixture. Carefully examine the chromatogram
obtained to verify that all the individual components of the test mixture are correctly identified as compared to the reference
chromatogram (Figs. 2 and 3). Test results for groups by hydrocarbon number and group totals shall agree with the known
D6839 − 21a
FIG. 2 Example of a Gravimetric Test Blend Analysis 1/2
FIG. 3 Example of a Gravimetric Test Blend Analysis 2/2
composition (see Table 2) within the 95 % confidence level or reproducibility of the group/component divided by the square root
of 2. Table 4 presents the calculated level for selected components or groups. If these specifications are met, proceed to the analysis
of the quality control samples (see 10.3).
10.2.1 If the specifications in 10.2 are not met, adjust the temperature of specific columns and traps or valve timing according to
the manufacturer’s guidelines and reanalyze the system validation test mixture until they are met.
10.3 Analyze quality control samples; see 8.6. Verify that results are consistent with those previously obtained and that the
separation of olefins and saturates is correct.
10.3.1 Breakthrough of olefins to the saturate fraction is indicated by a rising baseline under the C to C saturates region or
5 6
additional peaks between the C and C peaks. If breakthrough is observed, optimize the olefin trap temperature or, if necessary,
4 6
replace the trap.
10.3.2 If the fraction containing C to C olefins and C to C saturates shows peaks in the C region, optimize the olefin trap
4 6 7 10 7
temperatures or, if necessary, replace the trap.
D6839 − 21a
FIG. 4 Typical Gasoline Chromatogram 1/2
FIG. 5 Typical Gasoline Chromatogram 2/2
TABLE 4 Calculated Acceptance Levels for Validation Sample
Component Group Concentration Level Acceptance Level
Volume %
Aromatics 33.5 ±1.1
Olefins 3.5 ±0.9
Saturates 63.0 ±1.1
Benzene 1.9 ±0.11
10.3.3 Loadability limits for olefins are listed in 1.3. These limits depend on the condition of the olefin trap, and an aged trap may
not have this capacity. Use the quality control sample (see 8.6) to verify olefin capacity.
10.3.4 Check that the correct qualitative and quantitative analysis of oxygenates are achieved for the quality control sample. If
qualitative or quantitative specifications are not met, optimize the alcohol trap temperature and ether-alcohol-aromatic trap
temperature or replace the columns as necessary.
10.4 Reanalyze the system validation test mixture whenever the quality control sample does not conform to expected results (see
10.3) and make adjustments as necessary (see 10.2).
D6839 − 21a
A ,B
TABLE 5 Calculated Response Factors for Hydrocarbons
NOTE 1—Use a factor of 0.8830.874 for polynaphthenes.
No. of Mono-
Naph- Cyclo-
Carbon Paraffins Olefins and Aromatics
thenes Olefins
Atoms Diolefins
3 0.916 0.916
4 0.906 0.906
5 0.874 0.899 0.874 0.899
6 0.874 0.895 0.874 0.895 0.811
7 0.874 0.892 0.874 0.892 0.820
8 0.874 0.890 0.874 0.890 0.827
9 0.874 0.888 0.874 0.888 0.832
10 0.874 0.887 0.874 0.887 0.837
11+ 0.887 0.840
A
Based on percentage by mass of carbon, normalized to methane = 1.
B
Corrected for hydrogenation of olefins.
Part A—PROCEDURE APPLICABLE TO AUTOMOTIVE MOTOR GASOLINE AND HYDROCARBON STREAMS
WITH SIMILAR BOILING RANGES
11. Procedure
11.1 Load the necessary system setpoint conditions, which include initial component temperatures, times at which column and trap
temperature are changed, the initial positions of switching valves, and times when valve switches occur (see Note 6).
NOTE 6—Commercial systems will have all parameters predetermined and accessible through the software. Other constructed systems will require
experimentation and optimization of parameters to achieve the required component separation and precision.
11.2 When all component temperatures have stabilized at the analysis conditions, inject a representative aliquot of sample (or test
mixture) and start the analysis. Typically, 0.1 μL has been found to be suitable.
11.2.1 Starting the analysis should begin the data acquisition and should begin the timing function that controls all of the various
programmed temperature changes and valve switching.
11.2.2 Upon completion of its programmed cycle, the system should automatically stop, generate a chromatogram, and print a
report of concentrations.
12. Calculation
12.1 Calculations produce results that are reported in mass % and liquid volume %. Examine the report carefully to ensure that
all peaks have been properly identified and integrated.
12.1.1 Calculate the mass % of each identified hydrocarbon group of a particular carbon number and individual oxygenate using
Eq 1.
A 3F 3100
M 5 (1)
A 3F
(
where:
M = mass % of an identified hydrocarbon group of a particular carbon number or individual oxygenate,
A = integrated area of the hydrocarbon group of a particular carbon number or individual oxygenate,
F = relative response factor for the hydrocarbon group, RRf, calculated using Eq 2 or from Table 5. For oxygenates, use the
response factors from Table 6, or factors determined on the specific system (see 12.1.1.2), and
100 = factor to normalize corrected area % to 100 %.
12.1.1.1 Calculate the flame ionization detector response factor relative to methane, which is considered to have a response factor
of unity (1), for each hydrocarbon group type of a particular carbon number using Eq 2. Olefin response is calculated on a
hydrogenated basis.
D6839 − 21a
TABLE 6 Experimentally Determined Response Factors for
Oxygenates
Compound Response Factor
Ethanol 1.870
tert-Butanol 1.229
MTBE 1.334
ETBE 1.242
TAME 1.242
DIPE 1.317
Methanol 3.80
Methanol 3.000
n-Propanol 1.867
iso-Propanol 1.742
n-Butanol 1.546
iso-Butanol 1.390
sec-Butanol 1.390
C 3C 1 H 3H 30.7487
@~ ! ~ !#
aw n aw n
RRf 5 (2)
~C 3C !
aw n
where:
RRf = relative response factor for a hydrocarbon type group of a particular carbon number,
C = atomic mass of carbon, 12.011,
aw
C = number of carbon atoms in the hydrocarbon type group, of a particular carbon number,
n
H = atomic mass of hydrogen, 1.008,
aw
H = number of hydrogen atoms in the hydrocarbon type group of a particular carbon number, and
n
0.7487 = factor to normalize the result to a methane response of unity, (1).
12.1.1.2 Oxygenate flame ionization detector response factors used in the precision study were determined experimentally and are
listed in Table 6.
12.1.2 Calculate the liquid volume % of each identified hydrocarbon group and oxygenate using Eq 3.
M
D
V 5 (3)
M
(
D
where:
V = liquid volume % of an identified hydrocarbon group of a particular carbon number or individual oxygenate,
M = previously defined, Eq 1, and
D = average relative density, kg/L at 20 °C, (see Note 7) for the hydrocarbon group of a particular carbon number or individual
oxygenate. For hydrocarbons, use Table 7 and for oxygenates, use Table 8.
NOTE 7—Relative density of 15.5 °C can also be used but Tables 7 and 8 will not apply.
12.1.3 Calculate the oxygen content, w , from all identified oxygenate compounds, i, according to Eq 4:
O
n 3M
O O
w 5 Σ 3 w (4)
S D
O i
M
i i
where:
n = the number of oxygen atoms in the molecule, generally 1,
O
M = atomic mass of oxygen,
O
M = molecular mass of the oxygenated compound, and
i
w = percent mass fraction of the compound in the mixture.
i
12.1.3.1 Example—This example calculation uses MTBE (C H O) as the only oxygenate compound and the following atomic
5 12
masses:
D6839 − 21a
TABLE 7 Average Relative Density, kg/L at 20 °C, of Hydrocarbon
A
Type Groups
NOTE 1—Use an average relative density of 0.8832 for the polynaph-
thenes.
No. of Mono-
Naph- Cyclo-
Carbon Paraffins Olefins and Aromatics
thenes Olefins
Atoms Diolefins
3 0.5005 0.5139
4 0.5788 0.6037
5 0.7454 0.6262 0.7720 0.6474
6 0.7636 0.6594 0.7803 0.6794 0.8789
7 0.7649 0.6837 0.7854 0.7023 0.8670
8 0.7747 0.7025 0.8000 0.7229 0.8681
9 0.7853 0.7176 0.8073 0.7327 0.8707
10 0.8103 0.7300 0.8724
11+ 0.740 0.874
A
ASTM publication DS 4A, Physical Constants of Hydrocarbons. C11+ groups
utilize an average of data available from the Handbook of Chemistry and Physics,
69th Ed., 1988-1989. Available from ASTM International.
A
TABLE 8 Relative Density, kg/L at 20 °C, of Oxygenates
Oxygenate Relative Density
Ethanol 0.7967
tert-Butanol 0.7910
MTBE 0.7459
ETBE 0.7440
TAME 0.7710
DIPE 0.7240
Methanol 0.7965
n-Propanol 0.7925
iso-Propanol 0.7925
n-Butanol 0.8147
iso-Butanol 0.8052
sec-Butanol 0.8144
A
ASTM publication DS 4B, Physical Constants of Hydrocarbons, available from
ASTM International.
—C 12.011
—H 1.008
—O 16.000
n 3M
O O
w 5 Σ 3 w
S D
O i
M
i
1316.000
5 3w
i
5312.011112 31.00811316.000
5 0.1815 3w (5)
i
13. Report
13.1 Report the mass percent and liquid volume percent for each hydrocarbon group type to the nearest 0.1 % as listed in Table
9 and report the mass percent and liquid volume percent for individual carbon number components, each oxygenate, and the total
oxygen mass percent to the nearest 0.01 %.
13.1.1 Calculate the total for the saturates by summation of the C to C naphthenes, the C to C paraffins, the poly-naphthenes
5 10 3 10
and the C + saturates.
13.1.2 Calculate the total for the olefins by summation of the C to C cyclic olefins and the C to C mono and diolefins.
5 10 3 10
13.1.3 Calculate the total for the aromatics by summation of the C to C aromatics and the C + aromatics.
6 10 11
D6839 − 21a
TABLE 9 Reporting of Components
Hydrocarbon Group
Report, Mass % and LV %
Type and Oxygenates
Saturates Total, one decimal precision
Olefins Total, one decimal precision
Aromatics Total, one decimal precision
Oxygenates By Component, two decimals precision
Benzene Two decimals precision
Total Oxygen Two decimals precision
14. Precision and Bias
14.1 Precision—The precision of any individual measurement resulting from the application of this test method depends on
several factors related to the individual or group of components including the volatility, concentration, and degree to which the
component or group of components is resolved from closely eluting components or groups of components. As it is not practical
to determine the precision of measurement for every component or group of components at different levels of concentration
separated by this test method, Tables 10 and 11 present the repeatability and reproducibility values for selected, representative
components, and groups of components.
14.1.1 Repeatability—The difference between successive results obtained by the same operator with the same apparatus under
constant operating conditions on identical test materials would, in the long run, in the normal and correct operation of the test
method, exceed the repeatability values shown in Tables 10 and 11 only in one case in twenty.
14.1.2 Reproducibility—The difference between two single and independent results obtained by different operators working in
different laboratories on identical test materials would, in the long run, in the correct operation of the test method, exceed the values
shown in Tables 10 and 11 only in one case in twenty.
NOTE 8—Although the precision for benzene was determined in the range from 0.5 % to 1.6 % by mass, this test method can be used to determine a
mass fraction benzene concentration up to 5.0 %.
14.2 Bias—No information can be presented on the bias of the procedure in Test Method D6839 for measuring hydrocarbon types
because no material having an accepted reference value is available.
14.3 Relative Bias—A relative bias assessment of Test Method D6839 versus Test Method D1319 for the determination of total
olefins in spark-ignition engine fuel was conducted using data from the ASTM D02 Interlaboratory Crosscheck Program. The
assessment was performed in accordance with the requirements of Practice D6708 with a successful outcome. It was based on
measurements of total olefins in spark ignition fuels supplied between December 2010 and October 2014 by the Reformulated
Gasoline program of the ASTM Proficiency Testing Program (Interlaboratory Crosscheck Program) and is documented in Research
Report RR:D02-1818.
NOTE 9—In the United States, the EPA requires the measurement of total olefins in spark-ignition engine fuels by Test Method D1319. Effective Jan. 1,
2016, there is an allowance in the regulation to use other test methods if they are formally correlated with the specified test method by a consensus
organization, for example, ASTM. This relative bias statement is intended to satisfy the requirement and allow use of Test Method D6839 bias-corrected
results in the stated concentration ranges in place of Test Method D1319 for total olefins.
14.3.1 The degree of agreement between results from Test Method D6839 and Test Method D1319 can be further improved by
applying a correlation equation (Eq 6) (Research Report RR:D02-1818), and this correlation equation shall be utilized when
reporting compliance with EPA fuels program. There were no discernable sample-specific biases as defined in Practice D6708.
14.3.2 The correlation equation is:
Predicted Test Method D1319 = C (6)
D6839
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1544. Contact ASTM Customer
Service at service@astm.org.
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1818. Contact ASTM Customer
Service at service@astm.org.
D6839 − 21a
TABLE 10 Repeatability and Reproducibility for Selected
Oxygenate and Hydrocarbon Type Components and Groups of
Components
NOTE 1—The reporting unit for the covered range is in liquid volume
percent except for the level of oxygen, which is in weight percent.
Component or
Repeatability Reproducibility Covered Range
Group
Aromatics 0.012 (10 + X) 0.036· (10 + X) 20–45 v/v
0.46 0.46
Olefins 0.13 · X 0.72 · X 0–28 v/v
Saturates 0.5 1.6 25–80 v/v
Oxygen 0
...