ASTM D5186-24 用超临界流体色谱法测定柴油的芳香族化合物含量的试验方法

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Designation: D5186 −24
Standard Test Method for
Determination of the Aromatic Content and Polynuclear
Aromatic Content of Diesel Fuels By Supercritical Fluid
Chromatography
1
This standard is issued under the ﬁxed designation D5186; 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 determination of the total
amounts of monoaromatic and polynuclear aromatic hydrocar-
bon compounds in motor diesel fuels and blend stocks by
supercritical ﬂuid chromatography (SFC). The range of aro-
matics concentration to which this test method is applicable is
from 1 % to 75 % by mass. The range of polynuclear aromatic
hydrocarbon concentrations to which this test method is
applicable is from 0.5 % to 50 % by mass.
1.2 This test method includes relative bias for Test Method
D5186 versus Test Method D1319 and Test Method D6591
versus Test Method D5186 for diesel fuels. The applicable
ranges of the correlation ranges are presented in the Relative
Bias section. The correlations are applicable only in the stated
ranges and only to diesel fuels.
1.3 This test method and correlations were developed for
diesel samples not containing biodiesel; the presence of bio-
diesel will interfere with the results. The correlation equations
are only applicable between these concentration ranges and to
diesel fuels that do not contain biodiesel.
1.4 The values stated in SI units are to be regarded as
standard. The values stated in inch-pound units are for infor-
mation only.
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 appro-
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
2
D1319 Test Method for Hydrocarbon Types in Liquid Petro-
leum Products by Fluorescent Indicator Adsorption
D2425 Test Method for Hydrocarbon Types in Middle Dis-
tillates by Mass Spectrometry
D6299 Practice for Applying Statistical Quality Assurance
and Control Charting Techniques to Evaluate Analytical
Measurement System Performance
D6591 Test Method for Determination of Aromatic Hydro-
carbon Types in Middle Distillates—High Performance
Liquid Chromatography Method with Refractive Index
Detection
D6708 Practice for Statistical Assessment and Improvement
of Expected Agreement Between Two Test Methods that
Purport to Measure the Same Property of a Material
3. Terminology
3.1 Deﬁnitions of Terms Speciﬁc to This Standard:
3.1.1 critical pressure, n—that pressure needed to condense
a gas at the critical temperature.
3.1.2 critical temperature, n—the highest temperature at
which a gaseous ﬂuid may be converted to a liquid by means
of compression.
3.1.3 mononuclear aromatic hydrocarbons,
n—hydrocarbon compounds containing exactly one aromatic
ring. This group includes benzene, alkyl-substituted benzenes,
indans, tetralins, alkyl-substituted indans, and alkyl-substituted
tetralins.
3.1.4 polynuclear aromatic hydrocarbons, n—all hydrocar-
bon compounds containing two or more aromatic rings. These
rings may be fused as in naphthalene and phenanthrene, or
separate as in biphenyl.
1
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 D02.04.0C on Liquid Chromatography.
Current edition approved July 1, 2024. Published July 2024. Originally approved
in 1991. Last previous edition approved in 2022 as D5186 – 22. DOI: 10.1520/
D5186-24.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at www.astm.org/contact. For Annual Book of
ASTM Standards volume information, refer to the standard’s Document Summary
page on the ASTM website.
*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
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.
1

3.1.5 restrictor, n—a device, attached to the outlet of a

chromatographic column, to restrict the mobile phase ﬂow

such that the mobile phase is maintained in the supercritical

state throughout the chromatographic column.

3.1.6 supercritical ﬂuid, n—a ﬂuid maintained in a thermo-

dynamic state above its critical temperature and critical pres-

sure.

3.1.7 supercritical ﬂuid chromatography, n—a class of chro-

matography that employs supercritical ﬂuids as mobile phases.

4. Summary of Test Method

4.1 A small aliquot of the fuel sample is injected onto a

packed silica adsorption column and eluted using supercritical

carbon dioxide mobile phase. Monoaromatics and polynuclear

aromatics in the sample are separated from nonaromatics and

detected using a ﬂame ionization detector.

4.2 The detector response to hydrocarbons is recorded

throughout the analysis time. The chromatographic areas

corresponding to the monoaromatic, polynuclear aromatic, and

nonaromatic components are determined and the % by mass

content of each of these groups in the fuel is calculated by area

normalization.

5. Signiﬁcance and Use

5.1 The aromatic hydrocarbon content of motor diesel fuels

is a factor that can affect their cetane number and exhaust

emissions.

5.2 The United States Environmental Protection Agency

(USEPA) regulates the aromatic content of diesel fuels. Cali-

fornia Air Resources Board (CARB) regulations place limits on

the total aromatics content and polynuclear aromatic hydrocar-

bon content of motor diesel fuel, thus requiring an appropriate

analytical determination to ensure compliance with the regu-

lations. Producers of diesel fuels will require similar determi-

nations for process and quality control. This test method can be

used to make such determinations.

5.3 This test method is applicable to materials in the boiling

range of motor diesel fuels and is unaffected by fuel coloration.

Test Method D1319, which has been mandated by the USEPA

for the determination of aromatics in motor diesel fuel,

excludes materials with ﬁnal boiling points greater than 315 °C

(600 °F) from its scope. Test Method D2425 is applicable to

the determination of both total aromatics and polynuclear

aromatic hydrocarbons in diesel fuel, but is much more costly

and time consuming to perform.

5.4 Results obtained by this test method have been shown to

be statistically more precise than those obtained from Test

Method D1319 for typical diesel fuels, and this test method has

ashorter analysis time.

Results from this test method for total

polynuclear aromatic hydrocarbons are also expected to be at

least as precise as those of Test Method D2425.

6. Apparatus

6.1 Supercritical Fluid Chromatograph (SFC)—Any SFC

instrumentation can be used that has the following capabilities

and meets the performance requirements in Section 8.

6.1.1 Pump—The SFC instrumentation must include a

pump capable of delivering supercritical carbon dioxide to the

column without pressure ﬂuctuations and at constant ﬂow. The

pump is typically a single-stroke-type (syringe) pump or a

highly dampened reciprocating pump with pressure ﬂuctua-

tions not exceeding 60.3 % of the operating pressure.

6.1.2 Detector—This test method is limited to the use of the

ﬂame ionization detector (FID). The detector must have

sufficient sensitivity to detect 0.1 % by mass toluene in

hexadecane under instrument conditions employed in this test

method.

6.1.3 Column Temperature Control—The chromatograph

must be capable of column temperature control of at least

60.5 °C (1 °F) at the operating temperature.

6.1.4 Sample Inlet System—A liquid sample injection valve

is required, capable of reproducibly introducing samples in the

0.05 µL to 0.50 µL liquid volume range. The inlet system

should be operated at between 25 °C and 30 °C. The sample

inlet system must be connected to the chromatographic column

so that loss of chromatographic efficiency is avoided.

6.1.5 Post-column Restrictor—A device capable of main-

taining mobile phase supercritical conditions within the col-

umn and up to the detector inlet must be connected to the end

of the column.

6.1.6 Column—Any liquid or supercritical ﬂuid chromato-

graphic column may be used that provides separation of

nonaromatic, monoaromatic, and polynuclear aromatic hydro-

carbons and meets the performance requirements of Section 8.

6.1.7 Integrator—Means must be provided for the determi-

nation of both discrete chromatographic peak areas and the

accumulated area under the chromatogram. This can be done

by means of a computer or electronic integrator. The computer

or integrator must have the capability of correcting for baseline

shifts during the run.

6.1.8 Sample Filter—A microﬁlter of a porosity of 0.20 µm,

which is chemically-inert to hydrocarbon solvents, may be

used for the removal of microscopic particulate matter from the

sample solution that potentially may harm the injection valve

and affect system performance.

7. Reagents and Materials

7.1 Purity of Reagents—Reagent-grade chemicals shall be

used in all tests. Unless otherwise indicated, it is intended that

all reagents conform to the speciﬁcations of the Committee on

Analytical Reagents of the American Chemical Society where

such speciﬁcations are available.

Other grades may be used,

Supporting data (obtained in a comparison study of Test Methods D1319 and

D5186) have been ﬁled at ASTM International Headquarters and may be obtained

by requesting Research Report RR:D02-1276. Contact ASTM Customer Service at

www.astm.org/contact.

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. Pharma-

copeial Convention, Inc. (USPC), Rockville, MD.

D5186 − 24

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 Air—Zero grade (hydrocarbon-free) is used as the FID

oxidant. (Warning—Air is usually supplied as a compressed

gas under high pressure and supports combustion.)

7.3 Carbon Dioxide (CO

)—Supercritical ﬂuid chromato-

graphic grade, 99.99 % minimum purity, supplied pressurized

in a cylinder equipped with a dip tube for removal of liquid

. (Warning—Liquid at high pressure. Release of pressure

results in production of extremely cold solid CO

and gas,

which can dilute available atmospheric oxygen.)

7.4 Check Standard—A commercial standard reference

material, which has accepted reference values, in accordance

with Section 6 on Reference Materials in Practice D6299.

Alternatively, samples subjected to round robin may be used as

check standards. It is important that the standard deviation of

the values of the laboratory exchange program not be statisti-

cally greater than the reproducibility for the test method.

7.5 Hydrogen—Hydrogen of high quality (hydrocarbon-

free) is used as the fuel for the ﬂame ionization detector.

(Warning—Hydrogen is usually supplied under high pressure

and is extremely ﬂammable.)

7.6 Performance Mixture—A quantitative mixture of ap-

proximately 75 % by mass hexadecane (n-C

), 20 % by mass

toluene, 3 % by mass tetralin (1,2,3,4-tetrahydronaphthalene),

and 2 % by mass naphthalene is used for performance checks.

7.7 Quality Control Sample—A homogeneous material hav-

ing similar physical and chemical properties to the samples to

be analyzed. The choice of such material should be guided by

Section 6 on Reference Materials in Practice D6299. Examples

of such material can be motor diesel fuel or other typical

samples containing aromatics and polynuclear aromatics simi-

lar to the samples to be analyzed.

8. Preparation of Apparatus

8.1 Install the SFC instrumentation in accordance with the

manufacturer’s instructions. System operating conditions will

depend upon the column used and optimization of perfor-

mance. If the performance characteristics in terms of retention

and resolution, speciﬁed in 8.2, are not achieved, modify the

temperature, pressure, or mobile phase ﬂow rate to achieve

compliance. A column of low activity may be reactivated by

solvent rinsing using established liquid chromatography acti-

vation techniques.

NOTE 1—This temperature can be increased (up to 40 °C) if the

resolution between the monoaromatics and polynuclear aromatics is not

satisfactory. Lower temperatures are suggested to improve resolution

between nonaromatics and monoaromatics.

8.2 System Performance:

8.2.1 Resolution—Analyze the performance mixture pre-

pared in 7.6. The resolution between the nonaromatics and

monoaromatics (R

) must be at least four and resolution

between the monoaromatics and polynuclear aromatics (R

)

must be at least two when calculated in accordance with the

following equations:

52×

1.699 ×

(1)

52×

1.699 ×

(2)

where:

= time for the n-C

peak apex, s,

= time for the toluene peak apex, s,

= time for the tetralin peak apex, s,

= time for the naphthalene peak apex, s,

= peak width at half height of n-C

peak, s,

= peak width at half height of toluene, s,

= peak width at half height of tetralin, s, and

= peak width at half height of naphthalene, s.

8.2.2 Retention Time Reproducibility—Repeated injections

of the performance mixture must show a retention time

repeatability (maximum difference between duplicate runs) of

not more than 0.5 % for n-C

and toluene peaks.

8.2.3 Detector Accuracy Test—This test method assumes

that the FID response approximates the theoretical unit carbon

response. To verify this assumption, analyze the performance

mixture and calculate the response factors, relative to hexade-

cane (RRF

), for each of the components in the performance

mix, using the following equations:

(3)

RRF

5RF

C16

(4)

where:

= Component iin performance mix, % by area,

= Component i in performance mix, known % by

mass,

= response factor of Component i,

C16

= response factor of hexadecane in performance mix,

and

RRF

= relative response factor of Component i.

These values can then be compared to the theoretical

response factor for each component in the performance mix as

calculated by the following equation:

RRF

theo

12.01 ×n

226.4

12.01 ×16

(5)

where:

12.01 = atomic mass of carbon,

n= number of carbon atoms in component molecule,

MW = molecular mass of component,

226.4 = molecular mass of hexadecane, and

16 = number of carbon atoms in hexadecane molecule.

The measured RRF for each component in the test mixture

must be within 610 % of the theoretical value as calculated

with Eq 5 or summarized in Table 1. If this is not attained, it

will be necessary to vary the injection volume, restrictor

position, or detector gas ﬂows, or combination thereof, until

agreement is attained.

8.2.4 Detector Linearity Check:

8.2.4.1 The following procedure has been found to be useful

for verifying detector linearity. It is recommended that the

D5186 − 24

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标签： #超临界流体色谱法 #测定柴油 #芳香族化合物含量

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ASTM D5186-24 Standard Test Method for Determination of Aromatic Content and Polynuclear romatic Content of Diesel Fuels and Aviation Turbine Fuels by Supercritical Fluid Chromatography用超临界流体色谱法测定柴油的芳香族化合物含量的试验方法

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