ASTM D6159-23

Standard Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography

SIGNIFICANCE AND USE
4.1 High-purity ethylene is required as a feedstock for some manufacturing processes and the presence of trace amounts of certain hydrocarbon impurities can have deleterious effects. This test method is suitable for setting specifications, for use as an internal quality control tool, and for use in development or research work.  
4.2 This test method does not detect such impurities as H2O, CO, CO2, and alcohols that may be present in the sample. Hydrocarbons higher than n-decane cannot be analyzed by this test method, if present in the sample. Test Method D2504 addresses the analysis of noncondensable gases and Test Method D2505 addresses the analysis of CO2. Guide D5234 describes all potential impurities present in ethylene. These standards should be consulted when determining the total concentration of impurities in ethylene.
SCOPE
1.1 This test method covers the determination of methane, ethane, propane, propene, acetylene, iso-butane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene and 1,3-butadiene in high-purity ethylene. The purity of the ethylene can be calculated by subtracting the total percentage of all impurities from 100.00 %. Since this test method does not determine all possible impurities such as CO, CO2, H2O, alcohols, nitrogen oxides, and carbonyl sulfide, as well as hydrocarbons higher than decane, additional tests may be necessary to fully characterize the ethylene sample.  
1.2 Data are reported in this test method as ppmV (parts per million by gaseous volume) and ppmMol (parts per million Mol). This test method was evaluated in an interlaboratory cooperative study in the concentration range of 4 ppmV to 340 ppmV (2 mg/kg to 204 mg/kg). The participants in the interlaboratory cooperative study reported the data in non-SI units. Wherever possible, SI units are included.  
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-Apr-2023
• ICS: 71.040.50 - Physicochemical methods of analysis
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.D0.02 - Ethylene

Relations

• Refers: ASTM F307-13(2020) - Standard Practice for Sampling Pressurized Gas for Gas Analysis
• Effective Date: 01-Apr-2020
• Refers: ASTM D2505-88(2015) - Standard Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography (Withdrawn 2024)
• Effective Date: 01-Jun-2015
• Refers: ASTM D2504-88(2015) - Standard Test Method for Noncondensable Gases in C<inf>2</inf> and Lighter Hydrocarbon Products by Gas Chromatography (Withdrawn 2024)
• Effective Date: 01-Jun-2015
• Refers: ASTM F307-13 - Standard Practice for Sampling Pressurized Gas for Gas Analysis
• Effective Date: 01-Jun-2013
• Refers: ASTM D5234-92(2012) - Standard Guide for Analysis of Ethylene Product
• Effective Date: 01-Dec-2012
• Refers: ASTM D2504-88(2010) - Standard Test Method for Noncondensable Gases in C₂ and Lighter Hydrocarbon Products by Gas Chromatography
• Effective Date: 01-May-2010
• Refers: ASTM D2505-88(2010) - Standard Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography
• Effective Date: 01-May-2010
• Refers: ASTM D5234-92(2007) - Standard Guide for Analysis of Ethylene Product
• Effective Date: 01-Nov-2007
• Refers: ASTM F307-02(2007) - Standard Practice for Sampling Pressurized Gas for Gas Analysis
• Effective Date: 01-Apr-2007
• Refers: ASTM D2504-88(2004)e1 - Standard Test Method for Noncondensable Gases in C₂ and Lighter Hydrocarbon Products by Gas Chromatography
• Effective Date: 01-Nov-2004
• Refers: ASTM D2505-88(2004)e1 - Standard Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography
• Effective Date: 01-Nov-2004
• Refers: ASTM D5234-92(2002) - Standard Guide for Analysis of Ethylene Product
• Effective Date: 10-Dec-2002
• Refers: ASTM F307-02 - Standard Practice for Sampling Pressurized Gas for Gas Analysis
• Effective Date: 10-Oct-2002
• Refers: ASTM D2505-88(1998) - Standard Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography
• Effective Date: 10-Nov-1998
• Refers: ASTM D2504-88(1998) - Standard Test Method for Noncondensable Gases in C₂ and Lighter Hydrocarbon Products by Gas Chromatography
• Effective Date: 10-Nov-1998

Overview

ASTM D6159-23 is the Standard Test Method for Determination of Hydrocarbon Impurities in Ethylene by Gas Chromatography. Developed by ASTM International, this standard provides a procedure for the qualitative and quantitative analysis of specific hydrocarbon impurities in high-purity ethylene using gas chromatography (GC) equipped with a flame ionization detector (FID).

High-purity ethylene is a critical feedstock in various manufacturing processes, especially in the chemical and polymer industries. Trace hydrocarbon impurities can adversely affect these processes, making precise impurity determination essential for quality assurance, process optimization, and compliance with industry specifications. This test method is widely adopted for specification setting, quality control, research, and development purposes.

Key Topics

• Target Compounds: The method detects and quantifies methane, ethane, propane, propene, acetylene, iso-butane, propadiene, butane, trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene, and 1,3-butadiene in ethylene gas samples.
• Analytical Technique: Gas chromatography is the principal analytical tool, using a capillary column setup and a flame ionization detector to achieve sensitive and specific hydrocarbon identification.
• Data Reporting: Impurity concentrations are reported in both parts per million by volume (ppmV) and parts per million by mole (ppmMol). Typical measurement ranges are between 4 ppmV and 340 ppmV.
• Sample Preparation and Calibration:
  • Use of standard gas mixtures for calibration.
  • Regular verification of the linearity and sensitivity of the GC system.
  • Sampling is performed according to established protocols (e.g., ASTM F307).
• Limitations: This test method does not detect certain substances such as water, carbon monoxide, carbon dioxide, alcohols, nitrogen oxides, carbonyl sulfide, or hydrocarbons heavier than n-decane. Analysis of noncondensable gases and CO₂ requires reference to additional ASTM methods.

Applications

• Quality Control in Ethylene Production: Ensures compliance with high-purity ethylene specifications required for downstream processing and polymer manufacturing.
• Specification Setting: Establishes impurity limits in purchase, sales, and transportation contracts of high-purity ethylene.
• Research and Development: Supports process optimization, new material development, and investigation of impurity impact on process yields and catalyst lifetimes.
• Safety and Regulatory Compliance: Assists manufacturers in meeting safety, health, and environmental regulations by providing accurate impurity profiling.

Industries and stakeholders that benefit from ASTM D6159-23 include:

• Petrochemical and chemical industries
• Polymer manufacturers
• Industrial gas suppliers
• Analytical laboratories
• Regulatory and certification bodies

Related Standards

Compliance and a comprehensive impurity profile may require consultation of additional ASTM standards:

• ASTM D2504 - Test Method for Noncondensable Gases in C₂ and Lighter Hydrocarbon Products by Gas Chromatography
• ASTM D2505 - Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography
• ASTM D5234 - Guide for Analysis of Ethylene Product
• ASTM F307 - Practice for Sampling Pressurized Gas for Gas Analysis

For a complete assessment of all potential impurities in ethylene, these related standards should be referenced as recommended by ASTM D6159-23.

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Keywords: ethylene, hydrocarbon impurities, gas chromatography, ASTM D6159-23, flame ionization detector, high-purity gases, chemical analysis, quality control, impurity determination

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: D6159 − 23
Standard Test Method for
Determination of Hydrocarbon Impurities in Ethylene by Gas
Chromatography
This standard is issued under the fixed designation D6159; 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* D2504 Test Method for Noncondensable Gases in C and
Lighter Hydrocarbon Products by Gas Chromatography
1.1 This test method covers the determination of methane,
D2505 Test Method for Ethylene, Other Hydrocarbons, and
ethane, propane, propene, acetylene, iso-butane, propadiene,
Carbon Dioxide in High-Purity Ethylene by Gas Chroma-
butane, trans-2-butene, butene-1, isobutene, cis-2-butene,
tography
methyl acetylene and 1,3-butadiene in high-purity ethylene.
D5234 Guide for Analysis of Ethylene Product
The purity of the ethylene can be calculated by subtracting the
F307 Practice for Sampling Pressurized Gas for Gas Analy-
total percentage of all impurities from 100.00 %. Since this test
sis
method does not determine all possible impurities such as CO,
CO , H O, alcohols, nitrogen oxides, and carbonyl sulfide, as
2 2
3. Summary of Test Method
well as hydrocarbons higher than decane, additional tests may
be necessary to fully characterize the ethylene sample.
3.1 A gaseous ethylene sample is analyzed as received. The
1.2 Data are reported in this test method as ppmV (parts per
gaseous sample is injected into a capillary gas chromatograph.
million by gaseous volume) and ppmMol (parts per million
Sample may be introduced by direct valve injection or by split
Mol). This test method was evaluated in an interlaboratory
valve injection. The gas chromatograph is provided with a
cooperative study in the concentration range of 4 ppmV to
6-port sampling valve and two wide bore capillary columns
340 ppmV (2 mg ⁄kg to 204 mg ⁄kg). The participants in the
connected in series. These columns are a dimethyl polysi-
interlaboratory cooperative study reported the data in non-SI
loxane column and a porous layer open tubular column (PLOT)
units. Wherever possible, SI units are included.
Al O /KCl column. (See Note 1.) A flame ionization detector is
2 3
1.3 This standard does not purport to address all of the used for detection. The integrated detector signal (peak areas)
safety concerns, if any, associated with its use. It is the are corrected for detector response. The hydrocarbon impuri-
responsibility of the user of this standard to establish appro-
ties are determined and the total impurities are used to
priate safety, health, and environmental practices and deter-
determine the ethylene content.
mine the applicability of regulatory limitations prior to use.
NOTE 1—This column is supplied by major column manufacturers.
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Significance and Use
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4.1 High-purity ethylene is required as a feedstock for some
mendations issued by the World Trade Organization Technical
manufacturing processes and the presence of trace amounts of
Barriers to Trade (TBT) Committee.
certain hydrocarbon impurities can have deleterious effects.
This test method is suitable for setting specifications, for use as
2. Referenced Documents
an internal quality control tool, and for use in development or
2.1 ASTM Standards:
research work.
4.2 This test method does not detect such impurities as H O,
CO, CO , and alcohols that may be present in the sample.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Hydrocarbons higher than n-decane cannot be analyzed by this
Subcommittee D02.D0.02 on Ethylene.
test method, if present in the sample. Test Method D2504
Current edition approved May 1, 2023. Published June 2023. Originally
addresses the analysis of noncondensable gases and Test
approved in 1997. Last previous edition approved in 2017 as D6159 – 17. DOI:
10.1520/D6159-23.
Method D2505 addresses the analysis of CO . Guide D5234
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
describes all potential impurities present in ethylene. These
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
standards should be consulted when determining the total
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. concentration of impurities in ethylene.
*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
D6159 − 23
5. Apparatus
5.1 Gas Chromatograph (GC), a gas chromatographic in-
strument provided with a temperature programmable column
oven and a flame ionization detector (FID). Carrier gas is
regulated by pressure control.
5.2 Detector—A flame ionization detector (FID) having a
sensitivity of approximately 2.0 ppmV (1.2 mg ⁄kg) or less for
the compounds listed in 1.1. An FID was exclusively used in
the interlaboratory cooperative study.
5.3 Column Temperature Programmer—The chromatograph
shall be capable of linear programmed temperature operation
over a range sufficient for separation of the components of
FIG. 1 Direct Valve Injection Sample Introduction: Valve Off—
interest. Section 8 lists the recommended operating conditions.
Sample Loading
The programming rate shall be sufficiently reproducible to
obtain retention repeatability of 0.05 min (3 s) throughout the
scope of this analysis.
5.4 Columns—Couple the two columns in series with either
a glass press tight connector or a mini-connector equipped with
graphite ferrules.
5.4.1 Column 1, 50 m, 0.53 mm inside diameter (ID) KCl
deactivated Al O PLOT column. Relative retention is depen-
2 3
dent on the deactivation method of the column. Other deacti-
vated Al O plot columns using sulfates as the deactivating
2 3
agent were also used in the interlaboratory comparison.
5.4.2 Column 2, 30 m, 0.53 mm ID, 5 μm film thickness
methyl polysiloxane. This column improves the separation of
methyl acetylene, iso-pentane, and n-pentane.
5.5 Sample Inlet System—Two injection modes were used FIG. 2 Direct Valve Injection Sample Introduction: Valve On—
Injection
for the interlaboratory cooperative study.
5.5.1 A gas sampling valve placed in an unheated zone of
the gas chromatograph injecting the sample directly into the
column.
5.5.2 A gas sampling valve placed in an unheated zone of
the gas chromatograph in conjunction with a splitter injector
heated with a variable temperature control.
5.5.3 A gas sampling valve maintained at a constant tem-
perature above ambient temperature may also be used, for
example, by installation in a valve oven or equivalent.
5.6 Gas Sampling Valve and Injection System:
5.6.1 Direct Valve Injection—Use a 6-port valve provided
with ⁄16 in. fittings as the sample injection system. A typical
valve arrangement is shown in Fig. 1 and Fig. 2. A 10 μL to
60 μL loop as shown in Fig. 1 has proven satisfactory to attain
FIG. 3 Split Valve Injection Sample Introduction: Valve Off—
the detection limits described in this test method and not
Sample Loading
overload the column. Use good valve piping techniques to
minimize dead volumes, cold spots, and long connections; as
tory study. When using a splitter it is important to check
well as to ensure uniform heated zones. The preferred carrier
linearity of the splitter. Inject the standard blend at 50:1, 75:1,
gas control for sample introduction is pressure regulation. It is
and 100:1 split ratios. Check the response factors of the listed
recommended that linearity for the impurity components be
impurities as determined in 9.1, and the factors shall not vary
verified either from multiple standards or careful dilution of the
more than 3 %. Linearity may be verified when the system is
single calibration standard.
placed into service and when major maintenance is performed,
5.6.2 Split Valve Injection—Use a 6-port valve in conjunc-
such as installation of new GC columns.
tion with a splitter injector. A typical arrangement is shown in
Fig. 3 and Fig. 4. Split ratios of 50:1 to 100:1 at split injector 5.7 Data Acquisition System—Use a computerized data
temperatures of 150 °C to 200 °C yield acceptable results. acquisition system for peak area integration, as well as for
Loop sizes of 200 μL to 500 μL were used in the interlabora- recording the chromatographic trace.
D6159 − 23
TABLE 1 Typical Compounds and Retention Times for Common
A
Hydrocarbon Impurities in Ethylene
Components Retention Time, min
Methane 7.02
Ethane 8.12
Ethene 9.00
Propane 12.41
Propene 16.93
Ethyne 19.52
Isobutane 19.76
Propadiene 20.48
Butane 20.78
t-2-Butene 24.99
Butene-1 25.23
Isobutylene 25.90
c-2-Butene 26.71
Propyne 29.14
1,3-Butadiene 30.37
FIG. 4 Split Valve Injection Sample Introduction: Valve On—
A
Injection
Conditions as specified in Section 8.
6. Reagent Materials
NOTE 3—Hydrogen is an extremely flammable gas under high pressure.
6.1 Standard Mixture—Use a gravimetrically blended gas
6.4 Compressed Air—Air having less than 1.0 ppmV of
standard containing levels of 2 mg ⁄kg to 204 mg ⁄kg (4 ppmV
hydrocarbon impurities for the operation of the FID is recom-
to 340 ppmV as a gas) of each of the trace components listed
mended.
in Table 1 to calibrate the detector’s response. The standard gas
mixture shall be prepared gravimetrically from known raw
NOTE 4—Compressed air is a gas under high pressure and supports
materials, and cross contaminants shall be taken into account.
combustion.
The mixtures should be certified analytically such that the
6.5 Compressed Nitrogen—Nitrogen having less than
gravimetric and analytically derived values agree to an accept-
1.0 ppmV of hydrocarbon impurities is used as make up gas in
able tolerance; that is 6 1 % or 6 2 %. The concentration of
order to increase the response of the FID.
the minor components in the calibration standard shall be
NOTE 5—Compressed nitrogen is a gas under high pressure.
within 20 % to 50 % above the concentration of the process
stream or samples. Convert the gravimetric concentrations to
7. Sampling
ppm
...

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: D6159 − 17 D6159 − 23
Standard Test Method for
Determination of Hydrocarbon Impurities in Ethylene by Gas
Chromatography
This standard is issued under the fixed designation D6159; 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 methane, ethane, propane, propene, acetylene, iso-butane, propadiene, butane,
trans-2-butene, butene-1, isobutene, cis-2-butene, methyl acetylene and 1,3-butadiene in high-purity ethylene. The purity of the
ethylene can be calculated by subtracting the total percentage of all impurities from 100.00 %. Since this test method does not
determine all possible impurities such as CO, CO , H O, alcohols, nitrogen oxides, and carbonyl sulfide, as well as hydrocarbons
2 2
higher than decane, additional tests may be necessary to fully characterize the ethylene sample.
1.2 Data are reported in this test method as ppmV (parts per million by gaseous volume) and ppmMol (parts per million Mol).
This test method was evaluated in an interlaboratory cooperative study in the concentration range of 4 ppmV to 340 ppmV
(2 mg ⁄kg to 204 mg ⁄kg). The participants in the interlaboratory cooperative study reported the data in non-SI units. Wherever
possible, SI units are included.
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 and healthsafety, 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
2.1 ASTM Standards:
D2504 Test Method for Noncondensable Gases in C and Lighter Hydrocarbon Products by Gas Chromatography
D2505 Test Method for Ethylene, Other Hydrocarbons, and Carbon Dioxide in High-Purity Ethylene by Gas Chromatography
D5234 Guide for Analysis of Ethylene Product
F307 Practice for Sampling Pressurized Gas for Gas Analysis
3. Summary of Test Method
3.1 A gaseous ethylene sample is analyzed as received. The gaseous sample is injected into a capillary gas chromatograph. Sample
may be introduced by direct valve injection or by split valve injection. The gas chromatograph is provided with a 6-port sampling
valve and two wide bore capillary columns connected in series. These columns are a dimethyl polysiloxane column and a porous
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.D0.02 on Ethylene.
Current edition approved Jan. 1, 2017May 1, 2023. Published February 2017June 2023. Originally approved in 1997. Last previous edition approved in 20122017 as
D6159 – 97 (2012).D6159 – 17. DOI: 10.1520/D6159-17.10.1520/D6159-23.
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
D6159 − 23
layer open tubular column (PLOT) Al O /KCl column. (See Note 1.) A flame ionization detector is used for detection. The
2 3
integrated detector signal (peak areas) are corrected for detector response. The hydrocarbon impurities are determined and the total
impurities are used to determine the ethylene content.
NOTE 1—This column is supplied by major column manufacturers.
4. Significance and Use
4.1 High-purity ethylene is required as a feedstock for some manufacturing processes and the presence of trace amounts of certain
hydrocarbon impurities can have deleterious effects. This test method is suitable for setting specifications, for use as an internal
quality control tool, and for use in development or research work.
4.2 This test method does not detect such impurities as H O, CO, CO , and alcohols that may be present in the sample.
2 2
Hydrocarbons higher than n-decane cannot be analyzed by this test method, if present in the sample. Test Method D2504 addresses
the analysis of noncondensable gases and Test Method D2505 addresses the analysis of CO . Guide D5234 describes all potential
impurities present in ethylene. These standards should be consulted when determining the total concentration of impurities in
ethylene.
5. Apparatus
5.1 Gas Chromatograph (GC), a gas chromatographic instrument provided with a temperature programmable column oven and
a flame ionization detector (FID). Carrier gas is regulated by pressure control.
5.2 Detector—A flame ionization detector (FID) having a sensitivity of approximately 2.0 ppmV (1.2 mg ⁄kg) or less for the
compounds listed in 1.1. An FID was exclusively used in the interlaboratory cooperative study.
5.3 Column Temperature Programmer—The chromatograph shall be capable of linear programmed temperature operation over a
range sufficient for separation of the components of interest. Section 8 lists the recommended operating conditions. The
programming rate shall be sufficiently reproducible to obtain retention repeatability of 0.05 min (3 s) throughout the scope of this
analysis.
5.4 Columns—Couple the two columns in series with either a glass press tight connector or a mini-connector equipped with
graphite ferrules.
5.4.1 Column 1, 50 m, 0.53 mm inside diameter (ID) KCl deactivated Al O PLOT column. Relative retention is dependent on
2 3
the deactivation method of the column. Other deactivated Al O plot columns using sulfates as the deactivating agent were also
2 3
used in the interlaboratory comparison.
5.4.2 Column 2, 30 m, 0.53 mm ID, 5 μm film thickness methyl polysiloxane. This column improves the separation of methyl
acetylene, iso-pentane, and n-pentane.
5.5 Sample Inlet System—Two injection modes were used for the interlaboratory cooperative study.
5.5.1 A gas sampling valve placed in an unheated zone of the gas chromatograph injecting the sample directly into the column.
5.5.2 A gas sampling valve placed in an unheated zone of the gas chromatograph in conjunction with a splitter injector heated with
a variable temperature control.
5.5.3 A gas sampling valve maintained at a constant temperature above ambient temperature may also be used, for example, by
installation in a valve oven or equivalent.
5.6 Gas Sampling Valve and Injection System:
5.6.1 Direct Valve Injection—Use a 6-port valve provided with ⁄16 in. fittings as the sample injection system. A typical valve
arrangement is shown in Fig. 1 and Fig. 2. A 10 μL to 60 μL loop as shown in Fig. 1 has proven satisfactory to attain the detection
limits described in this test method and not overload the column. Use good valve piping techniques to minimize dead volumes,
D6159 − 23
FIG. 1 Direct Valve Injection Sample Introduction: Valve Off—Sample Loading
FIG. 2 Direct Valve Injection Sample Introduction: Valve On—Injection
cold spots, and long connections; as well as to ensure uniform heated zones. The preferred carrier gas control for sample
introduction is pressure regulation. It is recommended that linearity for the impurity components be verified either from multiple
standards or careful dilution of the single calibration standard.
5.6.2 Split Valve Injection—Use a 6-port valve in conjunction with a splitter injector. A typical arrangement is shown in Fig. 3 and
Fig. 4. Split ratios of 50:1 to 100:1 at split injector temperatures of 150 °C to 200 °C yield acceptable results. Loop sizes of 200 μL
to 500 μL were used in the interlaboratory study. When using a splitter it is important to check linearity of the splitter. Inject the
standard blend at 50:1, 75:1, and 100:1 split ratios. Check the response factors of the listed impurities as determined in 9.1, and
the factors shall not vary more than 3 %. Linearity may be verified when the system is placed into service and when major
maintenance is performed, such as installation of new GC columns.
5.7 Data Acquisition System—Use a computerized data acquisition system for peak area integration, as well as for recording the
chromatographic trace.
6. Reagent Materials
6.1 Standard Mixture—Use a gravimetrically blended gas standard containing levels of 2 mg ⁄kg to 204 mg ⁄kg (4 ppmV to 340
ppmV as a gas) of each of the trace components listed in Table 1 to calibrate the detector’s response. The standard gas mixture
shall be prepared gravimetrically from known raw materials, and cross contaminants shall be taken into account. The mixtures
should be certified analytically such that the gravimetric and analytically derived values agree to an acceptable tolerance; that is
6 1 % or 6 2 %. The concentration of the minor components in the calibration standard shall be within 20 % to 50 % above the
concentration of the process stream or samples. Convert the gravimetric concentrations to ppmMol and its equivalent gaseous
volumes ppmV as follows:
Mol 5 g ⁄MW (1)
i i i
D6159 − 23
FIG. 3 Split Valve Injection Sample Introduction: Valve Off—Sample Loading
FIG. 4 Split Valve Injection Sample Introduction: Valve On—Injection
TABLE 1 Typical Compounds and Retention Times for Common
A
Hydrocarbon Impurities in Ethylene
Components Retention Time, min
Methane 7.02
Ethane 8.12
Ethene 9.00
Propane 12.41
Propene 16.93
Ethyne 19.52
Isobutane 19.76
Propadiene 20.48
Butane 20.78
t-2-Butene 24.99
Butene-1 25.23
Isobutylene 25.90
c-2-Butene 26.71
Propyne 29.14
1,3-Butadiene 30.37
A
Conditions as specified in Section 8.
where:
Mol = the absolute mole from gravimetric standard of compound ‘i’ including ethylene,
i
g = is the mass in grams of compound ‘i’ from the gravimetric standard, and
i
MW = is the molecular weight of compound ‘i’.
i
and the ppmMol and ppmV can then be calculated as follows:
ppmMol 5 ppmV 5 10E6 × Mol ⁄ ΣMol (2)
@ # @ #
i i i iton
where:
ppmMol = final ppmMol of component ‘i’ in the calibration standard,
i
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...