ASTM D6591-00
(Test Method)Standard Test Method for Determination of Aromatic Hydrocarbon Types in Middle Distillates-High Performance Liquid Chromatography Method with Refractive Index Detection
Standard Test Method for Determination of Aromatic Hydrocarbon Types in Middle Distillates-High Performance Liquid Chromatography Method with Refractive Index Detection
SCOPE
1.1 This test method covers a high performance liquid chromatographic test method for the determination of mono-aromatic, di-aromatic, and polyaromatic hydrocarbon contents in diesel fuels and petroleum distillates boiling in the range from 150 to 400oC. The total aromatic content in % m/m is calculated from the sum of the individual aromatic hydrocarbon types.
Note 1--Aviation fuels and petroleum distillates with a boiling point range from 50 to 300oC are not determined by this test method and should be analyzed by Test Method, D6379 or other suitable equivalent test methods.
1.2 This test method is calibrated for distillates containing from 4 to 40 % (m/m) mono-aromatic hydrocarbons, 0 to 20 % (m/m) di-aromatic hydrocarbons, 0 to 6 % (m/m) polycyclic aromatic hydrocarbons, and 4 to 65 % (m/m) total aromatic hydrocarbons.
1.3 The precision of this test method has been established for diesel fuels and their blending components, containing from 4 to 40 % (m/m) mono-aromatic hydrocarbons, 0 to 20 % (m/m) di-aromatic hydrocarbons, 0 to 6 % (m/m) polycyclic aromatic hydrocarbons, and 4 to 65 % (m/m) total aromatic hydrocarbons.
1.4 Compounds containing sulfur, nitrogen, and oxygen are possible interferents. Mono-alkenes do not interfere, but conjugated di- and poly-alkenes, if present, are possible interferents.
1.5 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.
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An American National Standard
Designation: D 6591 – 00
Designation: 391/95
Standard Test Method for
Determination of Aromatic Hydrocarbon Types in Middle
Distillates—High Performance Liquid Chromatography
Method with Refractive Index Detection
This standard is issued under the fixed designation D 6591; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
This test method has the same title as IP 391-95 and is intended to be technically equivalent. 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 from 4 to 40 % (m/m) mono-aromatic hydrocarbons, 0 to 20 %
(m/m) di-aromatic hydrocarbons, 0 to 6 % (m/m) polycyclic
1.1 This test method covers a high performance liquid
aromatic hydrocarbons, and 4 to 65 % (m/m) total aromatic
chromatographic test method for the determination of mono-
hydrocarbons.
aromatic, di-aromatic, and polyaromatic hydrocarbon contents
1.4 Compounds containing sulfur, nitrogen, and oxygen are
in diesel fuels and petroleum distillates boiling in the range
possible interferents. Mono-alkenes do not interfere, but con-
from 150 to 400°C. The total aromatic content in % m/m is
jugated di- and poly-alkenes, if present, are possible interfer-
calculated from the sum of the individual aromatic hydrocar-
ents.
bon types.
1.5 This standard does not purport to address all of the
NOTE 1—Aviation fuels and petroleum distillates with a boiling point
safety concerns, if any, associated with its use. It is the
range from 50 to 300°C are not determined by this test method and should
responsibility of the user of this standard to establish appro-
be analyzed by Test Method, D 6379 or other suitable equivalent test
priate safety and health practices and determine the applica-
methods.
bility of regulatory limitations prior to use.
1.2 This test method is calibrated for distillates containing
from 4 to 40 % (m/m) mono-aromatic hydrocarbons, 0 to 20 %
2. Referenced Documents
(m/m) di-aromatic hydrocarbons, 0 to 6 % (m/m) polycyclic
2.1 ASTM Standards:
aromatic hydrocarbons, and 4 to 65 % (m/m) total aromatic
D 1319 Test Method for Hydrocarbon Types in Liquid
hydrocarbons.
Petroleum Products by Fluorescent Indicator Adsorption
1.3 The precision of this test method has been established
D 2425 Test Method for Hydrocarbon Types in Middle
for diesel fuels and their blending components, containing
Distillates by Mass Spectrometry
D 4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
This test method is under the jurisdiction of ASTM Committee D02 on
D 4177 Practice for Automatic Sampling of Petroleum and
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
Petroleum Products
D02.04 on Hydrocarbon Analysis.
This test method is based on material published in IP Standard Methods for
Analysis and Testing of Petroleum and Related Products and British Standard 2000
Parts, copyright The Institute of Petroleum, 61 New Cavendish Street, London
W1M 8AR. Adapted with permission of The Institute of Petroleum. Annual Book of ASTM Standards, Vol 05.01.
Current edition approved Dec. 10, 2000. Published February 2001. Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6591–00
D 5186 Test Method for Determination of Aromatic Con- after the elution of the DAHs, the column is backflushed to
tentandPolynuclearAromaticContentofDieselFuelsand elute the PAHs as a single sharp band.
Aviation Turbine Fuels by Supercritical Fluid Chromatog- 4.2 The column is connected to a refractive index detector
raphy that detects the components as they elute from the column.The
D 6379 Test Method for Determination ofAromatic Hydro- electronic signal from the detector is continually monitored by
carbonTypes inAviation Fuels and Petroleum Distillates – a data processor. The amplitudes of the signals (peak areas)
High Performance Liquid Chromatography Method With from the sample aromatics are compared with those obtained
Refractive Index Detection from previously-run calibration standards in order to calculate
2.2 IP Standard: percent m/m MAHs, DAHs, and PAHs in the sample. The sum
IP 391 Test Method for Determination of Aromatic Hydro- of MAHs, DAHs, and PAHs is reported as the total aromatic
carbon Types in Middle Distillates – High Performance content (percent m/m) of the sample.
Liquid Chromatography Method with Refractive Index
5. Significance and Use
Detection
5.1 The aromatic hydrocarbon content of motor diesel fuel
is a factor that can affect exhaust emissions and fuel combus-
3. Terminology
tion characteristics, as measured by cetane number.
3.1 Definitions of Terms Specific to This Standard:
5.2 The United States Environmental Protection Agency
3.1.1 di-aromatic hydrocarbons (DAHs), n—in this test
(US EPA) regulates the aromatic content of diesel fuels.
method, compounds that have a longer retention time on the
California Air Resources Board (CARB) regulations place
specified polar column than the mono-aromatic hydrocarbons.
limits on the total aromatics content and polynuclear aromatic
3.1.2 mono-aromatic hydrocarbons (MAHs), n—in this test
hydrocarbon content of motor diesel fuel, thus requiring an
method, compounds that have a longer retention time on the
appropriateanalyticaldeterminationtoensurecompliancewith
specifiedpolarcolumnthanthenon-aromatichydrocarbonsbut
the regulations.
a shorter retention time than the DAHs.
5.3 This test method is applicable to materials in the same
3.1.3 non-aromatic hydrocarbons, n—in this test method,
boiling range as motor diesel fuels and is unaffected by fuel
compounds that have a shorter retention time on the specified
coloration. Test Method D 1319, which has been mandated by
polar column than the mono-aromatic hydrocarbons.
the US EPAfor the determination of aromatics in motor diesel
3.1.4 polycyclic aromatic hydrocarbons (PAHs), n—in this
fuel, excludes materials with final boiling points greater than
testmethod,compoundsthathavelongerretentiontimesonthe
315°C (600°F) from its scope. Test Method D 2425 is appli-
specified polar column than the majority of DAHs.
cable to the determination of both total aromatics and poly-
3.1.5 total aromatic hydrocarbons, n—in this test method,
nuclear aromatic hydrocarbons in diesel fuel, but is much more
sum of the MAHs, DAHs, and PAHs.
costly and time-consuming to perform. Test Method D 5186,
3.1.5.1 Discussion—The elution characteristics of aromatic
currently specified by CARB, is also applicable to the deter-
and non-aromatic compounds on the specified polar column
mination of both total aromatics and polynuclear aromatic
have not been specifically determined for this test method.
hydrocarbons in diesel fuel. Test Method D 5186, however,
Published and unpublished data indicate the major constituents
specifies the use of supercritical fluid chromatography equip-
for each hydrocarbon type as follows: (1) non-aromatic hydro-
ment that may not be readily available.
carbons: acyclic and cyclic alkanes (paraffins and naphthenes),
mono-alkenes (if present), (2) MAHs: benzenes, tetralins,
NOTE 2—TestMethodD 5186waspreviouslyspecifiedbyCARBasan
indanes, thiophenes, and conjugated poly-alkenes, (3) DAHs: alternative to Test Method D 1319.
naphthalenes, biphenyls, indenes, fluorenes, acenaphthenes,
6. Apparatus
and benzothiophenes and dibenzothiophenes, (4) PAHs:
6.1 High Performance Liquid Chromatograph (HPLC)—
phenanthrenes, pyrenes, fluoranthenes, chrysenes, triph-
Any HPLC capable of pumping the mobile phase at flow rates
enylenes, and benzanthracenes.
between0.5and1.5mL/min,withaprecisionbetterthan0.5 %
4. Summary of Test Method and a pulsation of <1 % full scale deflection under the test
conditions described in Section 9.
4.1 Aknown mass of sample is diluted in the mobile phase,
6.2 Sample Injection System, capable of injecting 10 µL
and a fixed volume of this solution is injected into a high
(nominal) of sample solution with a repeatability >1 %.
performance liquid chromatograph, fitted with a polar column.
6.2.1 An equal and constant volume of the calibration and
This column has little affinity for the non-aromatic hydrocar-
sample solutions shall be injected into the chromatograph.
bons while exhibiting a pronounced selectivity for aromatic
Both manual and automatic sample injection systems (using
hydrocarbons. As a result of this selectivity, the aromatic
either complete or partial filling of the sample loop) will, when
hydrocarbons are separated from the non-aromatic hydrocar-
used correctly, meet the repeatability requirements laid down
bons into distinct bands in accordance with their ring structure,
in 6.2. When using the partial loop-filling mode, it is recom-
that is, MAHs, DAHs, and PAHs. At a predetermined time,
mended that the injection volume should be less than half the
total loop volume. For complete filling of the loop, best results
are obtained by overfilling the loop at least six times.
Annual Book of ASTM Standards, Vol 05.04.
6.2.2 Sample injection volumes other than 10 µL (typically
Available from Institute of Petroleum, 61 New Cavendish St., London, WIM
8AR, UK. in the range from 3 to 20 µL) may be used, provided they meet
D6591–00
the requirements laid down for injection repeatability (see 6.2), 7.2 Heptane, HPLC Grade. For use as HPLC mobile phase.
refractive index sensitivity and linearity (see 9.4.2 and 10.1.5), (WARNING—Heptane is highly flammable and may cause
and column resolution (see 9.4.3). irritation by inhalation, ingestion, or skin contact.)
6.3 Sample Filter, if required (see 10.2.1)—Amicrofilter of
NOTE 6—It is recommended practice to degas the HPLC mobile phase
porosity 0.45 µm or less, which is chemically-inert towards
before use.
hydrocarbon solvents, is recommended for the removal of
7.3 o-Xylene (1,2-Dimethylbenzene),$ 98 % pure.
particulate matter from the sample solutions.
7.4 1-Methylnaphthalene,$ 98 % pure.
6.4 Column System—Any stainless steel HPLC column(s)
7.5 Phenanthrene,$98 % pure.
packed with an approved amino-bonded (or polar amino/
7.6 Dibenzothiophene,$ 95 % pure.
cyano-bonded) silica stationary phase is suitable, provided it
7.7 9-Methylanthracene, $ 95 % pure. (WARNING—
meets the resolution requirements laid down in 9.4.3. Column
Gloves should be worn when handling aromatic compounds
lengths from 150 to 300 mm with an internal diameter from 4
(for example, disposable vinyl gloves).)
to 5 mm and packed with 3 or 5 µm particle size stationary
phase have been found to be satisfactory. The use of a guard NOTE 7—Purity is determined by gas chromatography with flame
ionization detection. The highest purity standards available should be
column (for example, 30 x 4.6-mm internal diameter) packed
used.
with silica or amino-bonded silica is recommended but not
essential.
8. Sampling
6.5 HPLC Column Oven—AnysuitableHPLCcolumnoven
8.1 The laboratory fuel sample from which an aliquot is
(block heating or air circulating) capable of maintaining a
being drawn for the purposes of this test method shall be
constant temperature (6 1°C) within the range from 20 to
representative of the lot of fuel. The laboratory sample should
40°C.
be obtained by following Practice D 4057 or D 4177, or a
NOTE 3—The refractive index detector is sensitive to both sudden and
similar standard.
gradual changes in the temperature of the eluent. All necessary precau-
tions should be taken to establish constant temperature conditions
9. Apparatus Preparation
throughout the liquid chromatograph system.
NOTE 4—Alternative forms of temperature control, for example, 9.1 Set up the chromatograph, injection system, column,
temperature-controlled laboratories, are permitted.
backflush valve, column oven, refractive index detector, and
computingintegratorinaccordancewiththeappropriateequip-
6.6 Backflush Valve—Any manual or automatic (air or
mentmanuals.InstalltheHPLCcolumnandbackflushvalvein
electrically actuated) flow-switching valve designed for use in
the column oven. Insert the backflush valve so that the detector
HPLC systems that is capable of operating at pressures up to 2
is always connected independently of the direction of flow
x10 kPa.
through the column (see Fig. 1). The sample injection valve
6.7 Refractive Index Detector—Any refractive index detec-
shall be maintained at the same temperature as the sample
tor may be used provided it is capable of being operated over
solution; in most cases this will be at room temperature.
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 8—The column oven is optional if alternative arrangements are
calibration range, and has a suitable output signal for the data
made to maintain a constant temperature environment, for example, a
system. If the refractive index detector has a facility for temperature-controlled laboratory (see 6.5).
independent temperature control, it is recommended that this
9.2 Adjusttheflowrateofthemobilephasetoaconstant1.0
be set at the same temperature as the column oven.
6 0.2 mL/min, and ensure the reference cell of the refractive
6.8 Computer or Computing Integrator—Any data system
indexdetectorisfullofmobilephase.Allowthetemperatureof
can be used provided it is compatible with the refractive index
the column oven (and refractive index detector, if equipped
detector, has a minimum sampling rate of 1 Hz, and is capable
with temperature control) to stabilize.
of peak area and retention time measurement. The data system
9.2.1 To minimize drift, it is essential to make sure the
should also have minimum facilities for post-analysis data
referencecellisfullofsolvent.Thebestwaytoaccomplishthis
processing, such as baseline correction and reintegration. The
iseither(1)toflushthemobilephasethroughthereferencecell
ability to perform automatic peak detection and identification
(then isolate the reference cell to prevent evaporation of the
and to calculate sam
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