ASTM D2268-21

Standard Test Method for Analysis of High-Purity <emph type="ital">n</emph>-Heptane and <emph type="ital">Iso</emph>octane by Capillary Gas Chromatography

SIGNIFICANCE AND USE
5.1 This test method is used for specification analysis of high-purity n-heptane and  isooctane, which are used as ASTM Knock Test Reference Fuels. Hydrocarbon impurities or contaminants, which can adversely affect the octane number of these fuels, are precisely determined by this method.
SCOPE
1.1 This test method covers and provides for the analysis of high-purity (greater than 99.5 % by volume) n-heptane and isooctane (2,2,4-trimethylpentane), which are used as primary reference standards in determining the octane number of a fuel. Individual compounds present in concentrations of less than 0.01 % can be detected. Columns specified by this test method may not allow separation of all impurities in reference fuels.  
1.2 The values stated in SI units are to be regarded as the standard.  
1.2.1 Exception—The values given in parentheses are for information only.  
1.3 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.  
1.4 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.

General Information

• Status: Published
• Publication Date: 30-Nov-2021
• ICS: 71.080.10 - Aliphatic hydrocarbons
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0L - Gas Chromatography Methods

Standards Content (Sample)

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.
Designation: D2268 − 21
Standard Test Method for
Analysis of High-Purity n-Heptane and Isooctane by
1
Capillary Gas Chromatography
This standard is issued under the fixed designation D2268; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* E594 Practice for Testing Flame Ionization Detectors Used
in Gas or Supercritical Fluid Chromatography
1.1 This test method covers and provides for the analysis of
high-purity (greater than 99.5 % by volume) n-heptane and
3. Terminology
isooctane (2,2,4-trimethylpentane), which are used as primary
3.1 Definitions:
referencestandardsindeterminingtheoctanenumberofafuel.
3.1.1 This test method makes reference to common gas
Individual compounds present in concentrations of less than
chromatographicprocedures,terms,andrelationships.Detailed
0.01 % can be detected. Columns specified by this test method
definitions of these can be found in Practices E355 and E594,
may not allow separation of all impurities in reference fuels.
and Terminology D4175.
1.2 The values stated in SI units are to be regarded as the
standard.
4. Summary of Test Method
1.2.1 Exception—The values given in parentheses are for
4.1 The sample is injected into a capillary gas chromato-
information only.
graphic column consisting of at least 61 m (200 ft) of stainless
1.3 This standard does not purport to address all of the
steel tubing (0.25 mm (0.010 in.) inside diameter), the inner
safety concerns, if any, associated with its use. It is the
walls of which are coated with a thin film of stationary liquid.
responsibility of the user of this standard to establish appro-
An inert gas transports the sample through the column, in
priate safety, health, and environmental practices and deter-
which it is partitioned into its individual components. As each
mine the applicability of regulatory limitations prior to use.
component is eluted from the column, it is detected with a
1.4 This international standard was developed in accor-
hydrogen flame ionization detector and recorded on a conven-
dance with internationally recognized principles on standard-
tional strip-chart recording potentiometer. The detector re-
ization established in the Decision on Principles for the
sponse from each impurity is then compared with that of a
Development of International Standards, Guides and Recom-
known quantity of an internal standard. After determining the
mendations issued by the World Trade Organization Technical
total impurity concentration, the n-heptane, or isooctane purity
Barriers to Trade (TBT) Committee.
is obtained by difference.
2. Referenced Documents
5. Significance and Use
2
2.1 ASTM Standards:
5.1 This test method is used for specification analysis of
D4175 Terminology Relating to Petroleum Products, Liquid
high-purity n-heptane and isooctane, which are used asASTM
Fuels, and Lubricants
Knock Test Reference Fuels. Hydrocarbon impurities or
E355 Practice for Gas Chromatography Terms and Relation-
contaminants, which can adversely affect the octane number of
ships
these fuels, are precisely determined by this method.
6. Apparatus
1
This test method is under the jurisdiction of ASTM Committee D02 on
6.1 Chromatograph—Gas chromatograph should be
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
equipped with a split-stream inlet device for introducing
Subcommittee D02.04.0L on Gas Chromatography Methods.
minute quantities of sample without fractionation, a capillary
Current edition approved Dec. 1, 2021. Published December 2021. Originally
column, and a hydrogen flame ionization detector. An elec-
approved in 1964. Last previous edition approved in 2017 as D2268 – 93 (2017).
DOI: 10.1520/D2268-21.
trometertoamplifythelowoutputsignalofthehydrogenflame
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
ionization detector, and a strip-chart recorder for recording the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
detector signal are needed. The time constant of neither the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. electrometernortherecordershouldexceed1 s.Aballanddisk
*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. Uni
...

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: D2268 − 93 (Reapproved 2017) D2268 − 21
Standard Test Method for
Analysis of High-Purity n-Heptane and Isooctane by
1
Capillary Gas Chromatography
This standard is issued under the fixed designation D2268; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method covers and provides for the analysis of high-purity (greater than 99.5 % by volume) n-heptane and isooctane
(2,2,4-trimethylpentane), which are used as primary reference standards in determining the octane number of a fuel. Individual
compounds present in concentrations of less than 0.01 % can be detected. Columns specified by this test method may not allow
separation of all impurities in reference fuels.
1.2 The values stated in SI units are to be regarded as the standard.
1.2.1 Exception—The values given in parentheses are for information only.
1.3 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.
1.4 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
2.1 ASTM Standards:
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
E355 Practice for Gas Chromatography Terms and Relationships
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
3. Terminology
3.1 Definitions:
3.1.1 This test method makes reference to common gas chromatographic procedures, terms, and relationships. Detailed definitions
of these can be found in Practices E355 and E594, and Terminology D4175.
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
D02.04.0L on Gas Chromatography Methods.
Current edition approved Oct. 1, 2017Dec. 1, 2021. Published November 2017December 2021. Originally approved in 1964. Last previous edition approved in 20132017
as D2268 – 93 (2013).(2017). DOI: 10.1520/D2268-93R17.10.1520/D2268-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
1

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D2268 − 21
4. Summary of Test Method
4.1 The sample is injected into a capillary gas chromatographic column consisting of at least 61 m (200 ft) of stainless steel tubing
(0.25 mm (0.010 in.) inside diameter), the inner walls of which are coated with a thin film of stationary liquid. An inert gas
transports the sample through the column, in which it is partitioned into its individual components. As each component is eluted
from the column, it is detected with a hydrogen flame ionization detector and recorded on a conventional strip-chart recording
potentiometer. The detector response from each impurity is then compared with that of a known quantity of an internal standard.
After determining the total impurity concentration, the n-heptane, or isooctane purity is obtained by difference.
5. Significance and Use
5.1 This test method is used for specification analysis of high-purity n-heptane and isooctane, which are used as ASTM Knock
Test Reference Fuels. Hydrocarbon impurities or contaminants, which can adversely affect the octane number of these fuels, are
precisely determined by this method.
6. Apparatus
6.1 Chromatograph—Gas chromatograph should be equipped with a split-stream inlet device for introducing minute quantities of
sample without fractionation, a capillary c
...