ASTM D6379-21e1

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.
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Designation: D6379 − 21
Designation: 436/20
Standard Test Method for
Determination of Aromatic Hydrocarbon Types in Aviation
Fuels and Petroleum Distillates—High Performance Liquid
1,2
Chromatography Method with Refractive Index Detection
This standard is issued under the fixed designation D6379; 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.
ε NOTE—Editorially corrected 9.4.3.1 in October 2021.
INTRODUCTION
This test method is intended to be technically equivalent to IP 436-20 with an identical title. The
ASTM format for test methods has been used, and where possible, equivalent ASTM test methods
have replaced the IP or ISO standards.
The test method is intended to be used as one of several possible alternative instrumental test
methods that are aimed at quantitative determination of hydrocarbon types in fuels. This does not
imply that a correlation necessarily exists between this and any other test method intended to give this
information, and it is the responsibility of the user to determine such correlation if necessary.
1. Scope* 0.7 % to 50 % by mass total aromatics. Although this method
generates results in m/m, results may also be quoted in v/v.
1.1 This test method covers a high performance liquid
chromatographic test method for the determination of mono-
1.3 The precision of this test method has been established
aromatic and di-aromatic hydrocarbon contents in aviation
forkeroseneboilingrangedistillatescontainingfrom0.40 %to
kerosenes and petroleum distillates boiling in the range from
44.0 % by mass mono-aromatic hydrocarbons, 0.02 % to
50 °C to 300 °C, such as Jet A or Jet A-1 fuels. The total
6.20 % by mass di-aromatic hydrocarbons, and 0.40 % to
aromatic content is calculated from the sum of the individual
50.0 %bymasstotalaromatics.Ifresultsarequotedinvolume,
aromatic hydrocarbon-types.
the precision is 0.3 % to 41.4 % by volume mono-aromatics,
0.01 % to 5.00 % by volume di-aromatics, and 0.30 % to
NOTE 1—Samples with a final boiling point greater than 300 °C that
46.3 % by volume total aromatics. As calculated by IP 367-1.
contain tri-aromatic and higher polycyclic aromatic compounds are not
determined by this test method and should be analyzed by Test Method
1.4 Compounds containing sulfur, nitrogen, and oxygen are
D6591 or other suitable equivalent test methods.
possible interferents. Mono-alkenes do not interfere, but con-
1.2 This test method is applicable to distillates containing
jugated di- and poly-alkenes, if present, are possible interfer-
from 0.8 % to 44.0 % by mass mono-aromatic hydrocarbons,
ents.
0.23 % to 6.20 % by mass di-aromatic hydrocarbons, and
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
This test method is under the jurisdiction of ASTM Committee D02 on
responsibility of the user of this standard to establish appro-
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
priate safety, health, and environmental practices and deter-
Subcommittee D02.04.0C on Liquid Chromatography. The technically equivalent
standardasreferencedisunderthejurisdictionoftheEnergyInstituteSubcommittee
mine the applicability of regulatory limitations prior to use.
SC-G-2.
1.6 This international standard was developed in accor-
Current edition approved July 15, 2021. Published September 2021. Originally
dance with internationally recognized principles on standard-
approved in 1999. Last previous edition approved in 2019 as D6379 – 11 (2019).
DOI: 10.1520/D6379-21E01.
ization established in the Decision on Principles for the
This test method has been developed through the cooperative effort between
Development of International Standards, Guides and Recom-
ASTM and the Energy Institute, London.ASTM and IPstandards were approved by
mendations issued by the World Trade Organization Technical
ASTMandEItechnicalcommitteesasbeingtechnicallyequivalentbutthatdoesnot
imply both standards are identical. Barriers to Trade (TBT) Committee.
*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
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D6379 − 21
2. Referenced Documents thearomatichydrocarbonsareseparatedfromthenon-aromatic
3 hydrocarbons into distinct bands in accordance with their ring
2.1 ASTM Standards:
structure, that is, MAHs and DAHs.
D4052 Test Method for Density, Relative Density, and API
Gravity of Liquids by Digital Density Meter 4.2 The column is connected to a refractive index detector
D4057 Practice for Manual Sampling of Petroleum and that detects the components as they elute from the column.The
Petroleum Products electronic signal from the detector is continually monitored by
D4177 Practice for Automatic Sampling of Petroleum and a data processor. The amplitudes of the signals (peak areas)
Petroleum Products from the sample aromatics are compared with those obtained
D6591 Test Method for Determination of Aromatic Hydro- from previously-run calibration standards in order to calculate
carbon Types in Middle Distillates—High Performance the percent m/m MAHs and DAHs in the sample. The sum of
Liquid Chromatography Method with Refractive Index the MAHs and DAHs is reported as the total aromatic content
Detection (percent m/m) of the sample. Although this method generates
2.2 Energy Institute Standards: results in m/m, results can also be quoted in percent v/v either
by calibrating in v/v or by converting m/m to v/v by using the
IP 367–1 (EN ISO 4259 Part 1) Petroleum and related
products – Precision of measurement methods and re- densities of the sample and standards.
sults – Part 1: Determination of precision data in relation
5. Significance and Use
to methods of test
IP 436 Test method for determination of automatic hydro-
5.1 Accurate quantitative information on aromatic hydro-
carbon types in aviation fuels and petroleum distillates—
carbon types can be useful in determining the effects of
High performance liquid chromatography method with
petroleum processes on production of various finished fuels.
refractive index
Thisinformationcanalsobeusefulforindicatingthequalityof
fuels and for assessing the relative combustion properties of
3. Terminology
finished fuels.
3.1 Definitions of Terms Specific to This Standard:
3.1.1 di-aromatic hydrocarbons (DAHs), n—compounds 6. Apparatus
that have a longer retention time on the specified polar column
6.1 High Performance Liquid Chromatograph (HPLC)—
than the MAHs.
Any high performance liquid chromatograph capable of pump-
3.1.2 mono-aromatic hydrocarbons (MAHs),
ing the mobile phase at flow rates between 0.5 mL⁄min and
n—compounds that have a longer retention time on the
1.5 mL⁄min with a precision better than 0.5 % and a pulsation
specifiedpolarcolumnthanthenon-aromatichydrocarbonsbut
of<1 %fullscaledeflectionunderthetestconditionsdescribed
a shorter retention time than the di-aromatic hydrocarbons.
in Section 9. See Fig. 1.
3.1.3 non-aromatic hydrocarbons, n—compounds that have
6.2 Sample Injection System—The sample injection system
a shorter retention time on the specified polar column than the
capable of injecting 5 µL (nominal) of sample solution with a
mono-aromatic hydrocarbons.
repeatability better than 2 %.
6.2.1 An equal and constant volume of the calibration and
3.1.4 total aromatic hydrocarbons, n—sum of the MAHs
sample solutions shall be injected into the chromatograph.
and DAHs.
Both manual and automatic sample injection systems (using
NOTE 2—The elution characteristics of aromatic and non-aromatic
either complete or partial filling of the sample loop) will, when
compounds on the specified polar column have not been specifically
used correctly, meet the repeatability requirements laid down
determined for this test method. Published and unpublished data indicate
the major constituents for each hydrocarbon type as follows: (1) Non- in 6.2. When using the partial loop filling mode, it is recom-
aromatic hydrocarbons: acyclic and cyclic alkanes (paraffins and
mended that the injection volume should be less than half the
naphthenes), mono-alkenes (if present). (2) MAHs: benzenes, tetralins,
total loop volume. For complete filling of the loop, best results
indanes, thiophenes, conjugated poly-alkenes. (3) DAHs: naphthalenes,
are obtained by overfilling the loop at least six times.
biphenyls, indenes, fluorenes, acenaphthenes, benzothiophenes.
6.2.2 Sampleinjectionvolumesotherthan5 µL(typicallyin
4. Summary of Test Method the range from 3 µLto 20 µL) may be used provided they meet
the requirements laid down for injection repeatability (see 6.2),
4.1 The test portion is diluted 1:1 with the mobile phase,
refractive index sensitivity and linearity (see 9.4 and 10.1), and
such as heptane, and a fixed volume of this solution injected
column resolution (see 9.4)
into a high performance liquid chromatograph fitted with a set
of polar columns. These columns have little affinity for the 6.3 Sample Filter (Optional)—A microfilter of porosity
non-aromatic hydrocarbons and exhibits a pronounced selec-
0.45 µm or less, which is chemically-inert towards hydrocar-
tivity for aromatic hydrocarbons.As a result of this selectivity, bon solvents, is recommended for the removal of particulate
matter from the sample solutions.
6.4 Column System—Any stainless steel HPLC column(s)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
packed with an approved amino-bonded (or polar amino/
Standards volume information, refer to the standard’s Document Summary page on
cyano-bonded) silica stationary phase is suitable. The col-
the ASTM website.
umn(s)usedshallsatisfytheresolutionrequirementslaiddown
Available from Energy Institute, 61 New Cavendish St., London, W1G 7AR,
U.K., http://www.energyinst.org. in 9.4.3. Column lengths from 150 mm to 300 mm with an
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D6379 − 21
FIG. 1 Example Chromatogram of an Aviation Fuel Showing Integration Points and Aromatic Hydrocarbon Type Groups
internal diameter from 4 mm to 5 mm and packed with 3 µm or 6.7 Computer or Computing Integrator—Any data system
5 µm particle size stationary phase have been found to be can be used provided it is compatible with the refractive index
satisfactory. The use of a guard column (for example, 30 mm detector, has a minimum sampling rate of 1 Hz, and is capable
by 4.6 mm internal diameter) packed with silica or amino- of peak area and retention time measurement. The data system
bonded silica is recommended but not essential. It has been should also have minimum facilities for post-analysis data
found that the use of a 2-column set provides the required processing, such as baseline correction and reintegration. The
separation and resolution for this method. Those used for the ability to perform automatic peak detection and identification
Inter-Laboratory study to generate the precision statements and to calculate sample concentrations from peak area mea-
were SphereClone 5 µm NH2 (250 mm by 4.6 mm) coupled surements is recommended but not essential.
with the Zorbax SB-CN 5 µm (150 mm by 4.6 mm). Other
6.8 Volumetric Flasks, Grade A, of 10 mL and 100 mL
columns are known to work when the separation (9.4.1) and
capacity.
resolution (9.4.3) criteria are met or exceeded prior to use.
6.9 Analytical Balance, accurate to 60.0001 g.
When joining two columns together, minimize the dead-
volume between the columns.
7. Reagents
6.5 HPLC Column Oven—Any suitable HPLC column oven
7.1 Cyclohexane, ≥99 % pure.
(block heating or air circulating) capable of maintaining a
constant temperature (61 °C) within the range from 20 °C to
NOTE 5—Cyclohexane may contain benzene as an impurity.
40 °C.
7.2 Heptane, HPLC Grade. For use as HPLC mobile phase.
NOTE 3—The refractive index detector is sensitive to both sudden and
(Warning—Hydrocarbon solvents are highly flammable and
gradual changes in the temperature of the eluent. All necessary precau-
may cause irritation by inhalation, ingestion, or skin contact.)
tions should be taken to establish constant temperature conditions
throughout the liquid chromatograph system.
NOTE 6—It is recommended practice to degas the HPLC mobile phase
NOTE 4—Alternative forms of temperature control, for example,
before use.
temperature-controlled laboratories, are permitted.
7.3 1-Methylnaphthalene, ≥97 % pure. (Warning—Gloves
6.6 Refractive Index Detector—Any refractive index detec-
should be worn when handling aromatic compounds (for
tor may be used provided it is capable of being operated over
example, disposable vinyl gloves).)
the refractive index range from 1.3 to 1.6, meets the sensitivity
requirement specified in 9.4.2, gives a linear response over the
NOTE 7—Purity is determined by gas chromatography with flame
calibration range, and has a suitable output signal for the data ionization detection. The highest purity standards available should be
used. Standards of ≥98 % purity are commercially available from all
system. If the refractive index detector has a facility for
major suppliers.
independent temperature control, it is recommended that this is
set at the same temperature as the column oven. 7.4 o-Xylene (1,2-Dimethylbenzene), ≥98 % pure.
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D6379 − 21
TABLE 1 Concentration Standards
7.5 1-phenyldodecane ≥97 %.
Calibration Standard
7.6 hexamethylbenzene ≥97 %.
AB C D
Cyclohexane g/100 mL 5.0 2.0 0.5 0.1
8. Sampling o-xylene g/100 mL 15.0 5.0 1.0 0.1
1-Methylnaphthalene g/100 mL 5.0 1.0 0.2 0.05
8.1 The laboratory fuel sample from which an aliquot is
being drawn for the purposes of this test method shall be
representative of the lot of fuel. The laboratory sample should
be obtained by following Practice D4057 or D4177,ora
Cyclohexane, 1-phenyldo
...