ASTM D8144-22

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Designation: D8144 − 18 D8144 − 22
Standard Test Method for
Separation and Determination of Aromatics, Nonaromatics,
and FAME Fractions in Middle Distillates by Solid-Phase
Extraction and Gas Chromatography
This standard is issued under the fixed designation D8144; 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—Footnote 4 was updated editorially in June 2019.
1. Scope Scope*
1.1 This test method covers the separation and determination of representative aromatics, nonaromatics, and fatty acid methyl ester
(FAME) fractions in middle distillates that boil between 170 °C and 400 °C, including biodiesel blends with up to 20 % by volume
of FAME, by solid phase extraction and gas chromatography.
1.2 This test method provides two procedures, A and B. Procedure A is applicable to the petroleum-based middle distillates fuel,
and Procedure B is applicable to the biodiesel blends with up to 20 % by volume of FAME.
1.3 This test method is applicable to middle distillates samples with aromatics content ranging from 5 % to 50 % by mass and
biodiesel blends with FAME content in the range of 0.5 % to 20 % by volume. This test method may apply to concentrations
outside these ranges, but the precision has not been determined.
1.4 For Procedure B, biodiesels in the form of fatty acid ethyl ester (FAEE) can also fully elute into the FAME fraction, and they
have the similar FID (flame ionization detector) relative response factors with that of FAME. The determined content of FAME
fractions are the sum of concentrations of FAME and FAEE by this test method (see 3.1.53.2.5).
1.5 From the investigation results obtained for FAME determination, the low concentrations of monoglycerides (usually less than
0.5 % by mass in biodiesel blends) are not detectable under the gas chromatographic (GC) condition of this test method and will
not interfere with the determination of FAME by Procedure B. As a result, biodiesel blends, conforming to the requirements of
Specification D7467, containing up to 20 % by volume of biodiesel blendstock meeting the requirements in Specification D6751,
typically contain concentrations of monoglycerides of less than 0.1 % by mass. The diglycerides and triglycerides, if present, are
not detected under the GC condition of this test method due to their higher boiling points.
NOTE 1—If a sample is suspected of containing an abnormal FAME biodiesel feedstock than specified in Specification D6751, for example, a sample
contaminated with vegetable oil with a high level of total triglycerides, the content of mono-, di-, or tri-glycerides in the isolated FAME fraction may
be determined using Test Method D6584. Samples containing biodiesels with a high amount of glycerides than specified in Specification D6751 may
contaminate the GC column and not recommended for this test method.
1.6 The values stated in acceptable SI units are to be regarded as the standard. No other units of measurement are included in this
standard
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 March 1, 2018Nov. 1, 2022. Published April 2018November 2022. Originally approved in 2018. Last previous edition approved in 2018 as
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D8144 – 18 . DOI: 10.1520/D8144-18E01.10.1520/D8144-22.
*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
D8144 − 22
1.7 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.
1.8 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:
D2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass Spectrometry
D2549 Test Method for Separation of Representative Aromatics and Nonaromatics Fractions of High-Boiling Oils by Elution
Chromatography
D2887 Test Method for Boiling Range Distribution of Petroleum Fractions by Gas Chromatography
D4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6584 Test Method for Determination of Total Monoglycerides, Total Diglycerides, Total Triglycerides, and Free and Total
Glycerin in B-100 Biodiesel Methyl Esters by Gas Chromatography
D6751 Specification for Biodiesel Fuel Blend Stock (B100) for Middle Distillate Fuels
D7467 Specification for Diesel Fuel Oil, Biodiesel Blend (B6 to B20)
2.2 Other Standards:
EN 14103 Fat and oil derivatives—Fatty Acid Methyl Esters (FAME)—Determination of ester and linolenic acid methyl ester
contents
EN 14214 Automotive fuels—Fatty acid methyl esters (FAME) for diesel engines—Requirements and test methods
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 aromatics fraction, n—the portion of the sample desorbed with the dichloromethane-ethyl alcohol mixture eluants
(Procedure A) and dichloromethane-n-hexane eluants (Procedure B); the aromatics fraction may contain aromatics, condensed
naphthenic-aromatics, aromatic olefins, and compounds containing sulfur, nitrogen, and oxygen atoms.
3.2.2 biodiesel, n—a fuel comprised of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats,
designated B100.
3.2.3 biodiesel blend, n—a blend of biodiesel fuel with petroleum-based diesel fuel.
3.2.4 diesel fuel, n—petroleum-based middle distillate fuel.
3.2.5 fatty acid methyl ester fraction, n—the portion of the diesel fuels blends with fatty acid methyl ester (FAME) eluted with
dichloromethane-ethyl alcohol; the FAME fraction may contain FAEE and compounds containing nitrogen and oxygen atoms.
3.2.6 nonaromatics fraction, n—the portion of the sample eluted with n-hexane.
3.2.6.1 Discussion—
The nonaromatics fraction is a mixture of paraffinic and naphthenic hydrocarbons if the sample is a straight-run material. If the
sample is a cracked stock, the nonaromatics fraction will also contain aliphatic and cyclic olefins.
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from British Standards Institution (BSI), 389 Chiswick High Rd., London W4 4AL, U.K., http://www.bsigroup.com.
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3.2.7 solid phase extraction separating system, n—a solid-phase extraction cartridge packed with stationary phase material to
effectively separate the aromatics, nonaromatics, and other compounds (such as FAME) fractions in middle distillates based on the
mechanism of solid phase extraction (SPE).
4. Summary of Test Method
4.1 Procedure A—The sample is charged to the top of a SPE column and separated into aromatics and nonaromatics fractions by
eluants with different polarities. Two aliquots of internal standards are added to these two fractions and both fractions are analyzed
by the gas chromatograph equipped with hydrogen flame ionization detector (GC-FID). The content of the aromatics and
nonaromatics are calculated based on the peak areas of the aromatics, nonaromatics, and internal standards.
4.2 Procedure B—The sample is charged to the top of a SPE column and separated into aromatics, nonaromatics, and FAME
fractions by eluants with different polarities. Three aliquots of internal standards are added to these three fractions. All of these
fractions are analyzed by the gas chromatograph equipped with hydrogen flame ionization detector (GC-FID). The content of the
aromatics, nonaromatics, and FAME fractions are calculated based on the peak areas of the aromatics, nonaromatics, FAME, and
internal standards. The volume percent of FAME is calculated based on the density of sample and mass percent of FAME.
5. Significance and Use
5.1 For the middle distillates whose boiling range is between 170 °C and 400 °C by such distillation methods like Test Method
D2887, Procedure A can separate and determine the content of total aromatics and total nonaromatics by SPE and GC analysis of
the resulting fractions. The determination of the total content of saturates and aromatics in petroleum middle distillates is useful
to investigate the effects of petroleum processes on production of various finished fuels.
5.2 The total aromatics content and polycyclic aromatics content are important to characterize the quality of diesel fuels. This test
method is demonstrated to be time-saving and eco-friendly by reducing the amount of reagent consumption and avoiding the
necessity of solvent evaporation step as required, for example, in such Test Method D2549.
5.3 The determination of detailed hydrocarbon composition by mass spectrometry requires a preliminary separation of the sample
into representative aromatics and nonaromatics, as in Test Method D2425, where Test Method D2549 is used to separate the
distillate fuel. The SPE fractionation procedure described herein may provide a suitable fractionation alternative approach for these
mass spectrometric types of methods.
5.4 Biodiesel is a blendstock commodity primarily used as a value-added blending component with diesel fuel. Procedure B can
provide a separation and determination technique to monitor the FAME content for FAME biodiesel blends.
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6. Apparatus
6.1 Solid Phase Extraction Separating System:
6.1.1 Solid Phase Extraction (SPE) Column, as shown in Fig. 1. The SPE column used in Section 11 is 3 mL column packed
with 1.5 g stationary phase particles. The stationary phase is a mixture 90:10 by mass of 75 μm to 150 μm silica gel and 75 μm
to 150 μm neutral aluminum oxide. Appropriate separation efficiency and activity are required for the SPE column to obtain a
satisfactory separation and quantification results. The detailed verification procedure and criteria for SPE column separation
efficiency are described in 10.1.
NOTE 2—Any automated solid phase extraction instrument that can perform this separation procedure with the satisfied separation efficiency can also be
used.
NOTE 3—The SPE column may be stored in a dry atmosphere as long as its performance meets the specifications; the SPE column is disposable and is
used only once.
6.1.2 Erlenmeyer flask, 10 mL10 mL.
6.1.3 Syringe, 2 mL and 0.25 mL.
6.1.4 Pipette, 1 mL.
6.1.5 Analytical Balance, capable of weighing to the nearest 0.0001 g.
6.2 Gas Chromatographic (GC) System—The gas chromatographic system shall be equipped with sample inlet system, capillary
column, column temperature programmer, FID detector and data acquisition system. Recommended GC operating conditions are
1 Sample Inlet
2 Adapter
3 Solid Phase Extraction Cartridge
4 Sieve-plate
5 Stationary Phase Particles
6 Sample Outlet
FIG. 1 Solid Phase Extraction Column
The sole source of supply of the apparatus (Solid Phase Extraction (SPE) Column that meets the requirements for this test method) known to the committee at this time
is Research Institute of Petroleum Processing, China Petroleum and Chemical Corporation, 18 Xueyuan Road, Beijing 100083, P. R. China. North American distribution is
through Dikma Technologies Inc. 255 Shields Court, Unit A&B, Markham, ON L3R 8V2, Canada, Toll-Free: 1-866-889-9072 or http://www.dikmatech.com. If you are aware
of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend.
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given in Table 1. The GC system and operating conditions shall ensure baseline separation of the solvent, sample and internal
standard as shown in Fig. 2 and Fig. 3. Any other gas chromatograph instrument and operating conditions capable of yielding
equivalent results may be used.
6.2.1 Sample Introduction System—Manual or recommended automated liquid syringe injection into a splitting inlet may be
employed. The sample amount reaching the column (combination of injection volume and split ratio) should meet the requirement
of separation efficiency and linear response calibration range.
6.2.2 Capillary Column—This test method is limited to the use of non-polar silica capillary columns. The column and conditions
shall provide separation of typical petroleum hydrocarbons in order of increasing boiling point. See Fig. 2 and Fig. 3 for examples
of acceptable separation.
6.2.3 Detector—This test method requires a flame ionization detector (FID). The detector shall have enough sensitivity, linearity,
and stability to meet performance requirements.
6.2.4 Data Acquisition System—A computerized data acquisition and reporting system is required to acquire, display, and process
GC data. The areas of chromatographic peaks can be determined through either manual or automated peak integration.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used in this test. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
A
TABLE 1 Recommended Operating Conditions of GC
Column Fused silica WCOT capillary column
Size 30 m × 0.25 mm ID, film thickness 0.25 μm
Stationary phase Non-polar, such as 100 % dimethyl polysiloxane
or 5 % phenyl-methyl polysiloxane
Column Temperature Program Initial oven temperature 60 °C, initial hold 2 min,
program rate 40 °C ⁄min, final oven temperature
300 °C, final hold 5 min
Inlet
Temperature 300 °C
Split ratio 20:1
Sample size 0.5 μL
Carrier gas
Type Helium, Nitrogen, or Hydrogen
Constant Flow Mode 1 mL ⁄min
Detector
Type Flame ionization detector (FID)
Temperature 350 °C
Fuel gas Hydrogen (~30 mL/min)
Oxidizing gas Air (~300 mL/min)
Make-up gas ~25 mL/min
A
The operating conditions given in this table are typical and may vary. The length
of the WCOT column can be 15 m to 30 m; the inner diameter can be 0.15 mm to
0.32 mm. The suitable oven program can be selected to ensure baseline separa-
tion of the solvent, sample ,and internal standard. See Fig. 2 and Fig. 3 for
examples of suitable resolution.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference Materials, American Chemical Society, Washington, DC. For
suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and
the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
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FIG. 2 Chromatograms of Nonaromatics and Aromatics Fractions in Petroleum-based Middle Distillate Fuel
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
7.2 Ethyl Alcohol, anhydrous, reagent grade. (Warning—Flammable.)
7.3 Dichloromethane, reagent grade. (Warning—Toxic. Harmful if inhaled or skin contact.)
7.4 n-hexane, reagent grade. (Warning—Flammable.)
7.5 n-hexadecane, reagent grade.
7.6 n-triacontane, reagent grade.
7.7 n-dotriacontane, reagent grade.
7.8 Methyl oleate, >99 %.
7.9 Internal Standard Solution, n-triacontane or n-dotriacontane dissolved in n-hexane solvent to obtain the mass concentrations
of 0.001 g/mL to 0.005 g/mL.
7.10 Silica Gel, 75 μm to 150 μm.
7.11 Aluminum oxide (neutral), 75 μm to 150 μm.
7.12 Carrier gas, Nitrogen, Helium, or Hydrogen, 99.99 % pure. (Warning—Compressed gas under high pressure.)
7.13 Hydrogen, 99.9 % pure. (Warning—Extremely flammable gas under high pressure.)
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FIG. 3 Chromatograms of Nonaromatics, Aromatics, and FAME Fractions in FAME Biodiesel Blends
7.14 Air, compressed, 99.9% pure. (Warning—Compressed gas under high pressure that supports combustion.)
7.15 Column Fractionation Effıciency Evaluation Mixture (Procedure A), used to evaluate the separation efficiency of SPE column
in Procedure A. The mixture can be prepared by pure saturates in the range of 50 % to 95 % by mass and pure aromatics in the
range of 5 % to 50 % by mass. The pure saturates can be a qualitative mixture of at least three paraffins from n-C to n-C .The
10 20
pure aromatics can be a qualitative mixture of at least three alkylbenzenes, such as C to C -benzene, naphthalene, and
4 12
phenanthrene. It is recommended that the concentrations of alkylbenzene and polycyclic aromatics are similar with that in a diesel
fuel sample. The representative compositions and concentrations for the evaluation mixtures are listed in Table A1.1 in Annex A1.
7.16 Column Fractionation Effıciency Evaluation Mixture (Procedure B), used to evaluate the separation efficiency of SPE column
in Procedure B. The mixture can be prepared by pure saturates in the range of 30 % to 95 % by mass, pure aromatics in the range
of 5 % to 50 % by mass and FAME in the range of 0.5 % to 20 % by volume. The pure saturates can be a qualitative mixture of
at least three paraffins from n-C to n-C . The pure aromatics can be a qualitative mixture of at least three alkylbenzenes, such
10 20
as C to C -benzene, naphthalene, and phenanthrene. It is recommended that the concentrations of alkylbenzene and polycyclic
4 12
aromatics are similar with that in a diesel fuel sample. Any FAME standard or a mixture of FAME standards can be used to prepare
this mixture. The representative composition and concentrations for the evaluation mixtures are listed in Table A1.2 in Annex A1.
7.17 Relative Response Factor Mixture, used to calculate the relative response factor of FAME (relative to n-hexadecane). Prepare
D8144 − 22
a quantitative mixture of methyl oleate (see Note 4) and n-hexadecane at the weight ratio of 1:1. Use n-hexane as the solvent to
provide a solution with a mass percent of 1 %.
NOTE 4—Any FAME standard or a mixture of FAME standard can be used as the reference to calculate the relative response factor.
7.18 Quality Control Sample (Procedure A), used to routinely monitor the operation of the gas chromatographic system and verify
that the reported concentrations are within the precision of the test method. The quality control (QC) sample is prepared by
weighing and blending a certain mass of aromatics and nonaromatics fractions, which are separated from Test Method D2549. The
composition of QC sample shall be similar with that in test sample.
7.19 Quality Control Sample (Procedure B), used to routinely monitor the operation of the gas chromatographic system and verify
that the reported concentration are within the precision of the test method. The quality control (QC) sample is prepared by weighing
and blending a certain mass of FAME biodiesel with the aromatics and nonaromatics fractions, which are separated from Test
Method D2549. The composition of QC sample shall be similar with that in test sample.
7.20 Reference Sample of Middle Distillates, middle distillates with known content of aromatics and nonaromatics fractions, a
check standard meeting the requirement in Practice D6299 with accepted reference value (ARV) determined by Test Method
D2549.
7.21 Reference Sample blended with FAME, diesel fuel with known content of aromatics, nonaromatics, and FAME, a check
standard prepared by spiking the weighed FAME into the reference sample listed in 7.20. The ARV shall be determined in
accordance with their blended weight ratio.
8. Sampling
8.1 Unless otherwise specified, samples shall be obtained in accordance with Practices D4057, D4177, or other comparable
practices. Samples should be stored in sealed containers.
9. Preparation of Apparatus
9.1 Chromatograph—Place in service and maintain in accordance with the manufacturer’s instructions. Typical operating
conditions are shown in Table 1, but manufacturer’s recommendations should be followed when possible.
10. Standardization and Verification
10.1 Verification of the Separation Effıciency of the SPE Column:
10.1.1 For a new batch of SPE columns or a new stationary phase used in the SPE column, or when overall performance criteria
are not being met, it is necessary to determine the separation efficiency of the column in accordance with the procedure as follows.
10.1.2 Use the separation efficiency evaluation mixture listed in 7.15 and 7.16 to evaluate the separatio
...