ASTM D5623-24

Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection

SIGNIFICANCE AND USE
5.1 Gas chromatography with sulfur selective detection provides a rapid means to identify and quantify sulfur compounds in various petroleum feeds and products. Often these materials contain varying amounts and types of sulfur compounds. Many sulfur compounds are odorous, corrosive to equipment, and inhibit or destroy catalysts employed in downstream processing. The ability to speciate sulfur compounds in various petroleum liquids is useful in controlling sulfur compounds in finished products and is frequently more important than knowledge of the total sulfur content alone.
SCOPE
1.1 This test method covers the determination of volatile sulfur-containing compounds in light petroleum liquids. This test method is applicable to distillates, gasoline motor fuels (including those containing oxygenates) and other petroleum liquids with a final boiling point of approximately 230 °C (450 °F) or lower at atmospheric pressure. The applicable concentration range will vary to some extent depending on the nature of the sample and the instrumentation used; however, in most cases, the test method is applicable to the determination of individual sulfur species at levels of 0.1 mg/kg to 100 mg/kg.  
1.2 The test method does not purport to identify all individual sulfur components. Detector response to sulfur is linear and essentially equimolar for all sulfur compounds within the scope (1.1) of this test method; thus both unidentified and known individual compounds are determined. However, many sulfur compounds, for example, hydrogen sulfide and mercaptans, are reactive and their concentration in samples may change during sampling and analysis. Coincidently, the total sulfur content of samples is estimated from the sum of the individual compounds determined; however, this test method is not the preferred method for determination of total sulfur.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.4 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.  
1.5 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: 29-Feb-2024
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0L - Gas Chromatography Methods

Relations

• Replaces: ASTM D5623-19 - Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection
• Effective Date: 01-Mar-2024
• Referred By: ASTM D7807-20 - Standard Test Method for Determination of Boiling Range Distribution of Hydrocarbon and Sulfur Components of Petroleum Distillates by Gas Chromatography and Chemiluminescence Detection
• Effective Date: 01-Mar-2024
• Referred By: ASTM D5273-23 - Standard Guide for Analysis of Propylene Concentrates
• Effective Date: 01-Mar-2024
• Referred By: ASTM D6733-01(2020) - Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 50-Metre Capillary High Resolution Gas Chromatography
• Effective Date: 01-Mar-2024
• Referred By: ASTM D7493-22 - Standard Test Method for Online Measurement of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatograph and Electrochemical Detection
• Effective Date: 01-Mar-2024
• Referred By: ASTM D6730-22 - Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100-Metre Capillary (with Precolumn) High-Resolution Gas Chromatography
• Effective Date: 01-Mar-2024
• Referred By: ASTM D1835-22 - Standard Specification for Liquefied Petroleum (LP) Gases
• Effective Date: 01-Mar-2024
• Referred By: ASTM D7995-19 - Standard Test Method for Total Water in Liquid Butane by Liquefied Gas Sampler and Coulometric Karl Fischer Titration
• Effective Date: 01-Mar-2024
• Referred By: ASTM D6729-20 - Standard Test Method for Determination of Individual Components in Spark Ignition Engine Fuels by 100 Metre Capillary High Resolution Gas Chromatography
• Effective Date: 01-Mar-2024

Overview

ASTM D5623-24: Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection is an internationally recognized method utilized for the rapid identification and quantification of volatile sulfur-containing compounds in light petroleum liquids. Issued by ASTM International, this standard is widely applied in the petroleum industry to analyze products such as gasoline, distillates, and other petroleum liquids with a final boiling point of approximately 230 °C (450 °F) or lower. The test method employs gas chromatography coupled with sulfur selective detection, enabling detailed analysis of both known and unknown sulfur species within concentrations ranging typically from 0.1 mg/kg to 100 mg/kg.

Key Topics

• Scope and Applicability: This method is suitable for the determination of volatile sulfur compounds in a broad range of light petroleum liquids, including gasoline motor fuels with or without oxygenates.
• Analytical Approach: The procedure uses gas chromatography (GC) with a sulfur selective detector (such as sulfur chemiluminescence or atomic emission) to provide both qualitative and quantitative results.
• Speciation of Sulfur Compounds: Instead of offering only a total sulfur content, the method allows for the identification and control of individual sulfur compounds, which is critical due to their varying odor, corrosivity, and catalytic effects.
• Concentration Range: The method reliably measures sulfur species at levels commonly found in petroleum products, from 0.1 mg/kg up to 100 mg/kg.
• Precision and Limitations: The method offers repeatability and reproducibility metrics for sulfur determination. It does not, however, identify all possible sulfur components, and is not designed for total sulfur quantification in all matrices, such as liquefied petroleum gases.
• Safety Considerations: Users must follow appropriate safety, health, and environmental practices due to the volatile and sometimes hazardous nature of the chemicals involved.

Applications

ASTM D5623-24 has practical applications across the petroleum supply chain, including:

• Quality Control: Monitoring and controlling sulfur compound content in refined petroleum products to meet regulatory and customer specifications.
• Catalyst Protection: Detecting sulfur compounds that may be corrosive or act as catalysts poisons, helping prevent equipment damage and process downtime.
• Odor Management: Identifying and quantifying odorous sulfur compounds to ensure product acceptability and compliance with environmental standards.
• Specification Compliance: Supporting the formulation and blending of fuels by providing accurate, detailed sulfur compound profiles for gasoline, diesel, and other light petroleum fractions.
• Research and Development: Enabling advanced analysis for process development, troubleshooting, and optimization of petroleum refining operations.

Related Standards

ASTM D5623-24 references and aligns with several related international standards and industry practices to ensure consistency and comparability of results, including:

• ASTM D2622: Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
• ASTM D3120: Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry
• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• ASTM D4307: Practice for Preparation of Liquid Blends for Use as Analytical Standards
• ASTM D4626: Practice for Calculation of Gas Chromatographic Response Factors
• ASTM D5504: Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and Chemiluminescence
• GPA 2199: Determination of Specific Sulfur Compounds by Capillary Gas Chromatography and Sulfur Chemiluminescence Detection

Keywords: ASTM D5623-24, sulfur compounds, light petroleum liquids, gas chromatography, sulfur selective detection, sulfur speciation, gasoline, distillates, quality control, refinery analysis, fuel standards.

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: D5623 − 24
Standard Test Method for
Sulfur Compounds in Light Petroleum Liquids by Gas
Chromatography and Sulfur Selective Detection
This standard is issued under the fixed designation D5623; 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* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers the determination of volatile
sulfur-containing compounds in light petroleum liquids. This
2. Referenced Documents
test method is applicable to distillates, gasoline motor fuels
(including those containing oxygenates) and other petroleum 2.1 ASTM Standards:
liquids with a final boiling point of approximately 230 °C D2622 Test Method for Sulfur in Petroleum Products by
(450 °F) or lower at atmospheric pressure. The applicable Wavelength Dispersive X-ray Fluorescence Spectrometry
concentration range will vary to some extent depending on the D3120 Test Method for Trace Quantities of Sulfur in Light
nature of the sample and the instrumentation used; however, in Liquid Petroleum Hydrocarbons by Oxidative Microcou-
most cases, the test method is applicable to the determination lometry
of individual sulfur species at levels of 0.1 mg ⁄kg to D4057 Practice for Manual Sampling of Petroleum and
100 mg ⁄kg. Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid
1.2 The test method does not purport to identify all indi-
Fuels, and Lubricants
vidual sulfur components. Detector response to sulfur is linear
D4307 Practice for Preparation of Liquid Blends for Use as
and essentially equimolar for all sulfur compounds within the
Analytical Standards
scope (1.1) of this test method; thus both unidentified and
D4626 Practice for Calculation of Gas Chromatographic
known individual compounds are determined. However, many
Response Factors
sulfur compounds, for example, hydrogen sulfide and
D5504 Test Method for Determination of Sulfur Compounds
mercaptans, are reactive and their concentration in samples
in Natural Gas and Gaseous Fuels by Gas Chromatogra-
may change during sampling and analysis. Coincidently, the
phy and Chemiluminescence
total sulfur content of samples is estimated from the sum of the
E355 Practice for Gas Chromatography Terms and Relation-
individual compounds determined; however, this test method is
ships
not the preferred method for determination of total sulfur.
2.2 Other Standard:
1.3 The values stated in SI units are to be regarded as
GPA 2199 Determination of Specific Sulfur Compounds by
standard. The values given in parentheses after SI units are
Capillary Gas Chromatography and Sulfur Chemilumines-
provided for information only and are not considered standard.
cence Detection
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety, health, and environmental practices and deter-
3.1.1 For definitions of terms used in this test method, refer
mine the applicability of regulatory limitations prior to use.
to Terminology D4175 and Practice E355.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Summary of Test Method
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4.1 The sample is analyzed by gas chromatography with an
appropriate sulfur selective detector. Calibration is achieved by
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. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2024. Published March 2024. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1994. Last previous edition approved in 2019 as D5623 – 19. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D5623-24. 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
D5623 − 24
the use of an appropriate internal or external standard. All equimolar response on a sulfur basis, (4) no interference or
sulfur compounds are assumed to produce equivalent response quenching from co-eluting hydrocarbons at the GC sampling
as sulfur. volumes used.
4.2 Sulfur Detection—As sulfur compounds elute from the 6.2 Column—Any column providing adequate resolution of
gas chromatographic column they are quantified by a sulfur the components of interest may be used. Using the column and
selective detector that produces a linear and equimolar re- typical operating conditions as specified in 6.2.1, the retention
sponse to sulfur compounds; for example, a sulfur chemilumi- times of some sulfur compounds will be those shown in Table
nescence detector or atomic emission detector used in the 1. The column must demonstrate a sufficiently low liquid phase
sulfur channel. bleed at high temperature, such that loss of the detector
response is not encountered while operating at the highest
5. Significance and Use
temperature required for the analysis.
6.2.1 Typical Operating Conditions:
5.1 Gas chromatography with sulfur selective detection
6.2.1.1 Column—30 m by 0.32 mm inside diameter fused
provides a rapid means to identify and quantify sulfur com-
silica wall coated open tube (WCOT) column, 4 μm thick film
pounds in various petroleum feeds and products. Often these
of methylsilicone.
materials contain varying amounts and types of sulfur com-
6.2.1.2 Sample size—0.1 μL to 2.0 μL.
pounds. Many sulfur compounds are odorous, corrosive to
6.2.1.3 Injector—Temperature 275 °C; Split ratio: 10:1
equipment, and inhibit or destroy catalysts employed in down-
(10 % to column).
stream processing. The ability to speciate sulfur compounds in
6.2.1.4 Column Oven—10 °C for 3 min, 10 °C ⁄min to
various petroleum liquids is useful in controlling sulfur com-
250 °C, hold as required.
pounds in finished products and is frequently more important
6.2.1.5 Carrier Gas—Helium, Head pressure: 70 kPa to
than knowledge of the total sulfur content alone.
86 kPa (10 psig to 13 psig).
6.2.1.6 Detector—Sulfur chemiluminescence detector.
6. Apparatus
6.3 Data Acquisition:
6.1 Chromatograph—Use a gas chromatograph (GC) that
6.3.1 Integrator—The use of an electronic integrating de-
has the following performance characteristics:
vice or computer is recommended for determining the detector
6.1.1 Column Temperature Programmer—The chromato-
response. The device and software must have the following
graph must be capable of linear programmed temperature
capabilities: (1) graphic presentation of the chromatogram, (2)
operation over a range sufficient for separation of the compo-
digital display of chromatographic peak areas, (3) identifica-
nents of interest. The programming rate must be sufficiently
tion of peaks by retention time or relative retention time, or
reproducible to obtain retention time repeatability of 0.05 min
both, (4) calculation and use of response factors, (5) internal
(3 s) throughout the scope of this analysis.
standardization, external standardization, and data presenta-
6.1.2 Sample Inlet System—The sample inlet system must
tion.
have variable temperature control capable of operating con-
tinuously at a temperature up to the maximum column tem-
perature employed. The sample inlet system must allow a
TABLE 1 Typical Retention Times for Common Sulfur
constant volume of liquid sample to be injected by means of a
A
Compounds
syringe or liquid sampling valve.
Sulfur Compounds Retention Time (min)
6.1.3 Carrier and Detector Gas Control—Constant flow
Hydrogen Sulfide 0.95
control of carrier and detector gases is critical to optimum and Carbonyl Sulfide 1.21
Sulfur Dioxide 1.34
consistent analytical performance. Control is best provided by
Methanethiol 3.43
the use of pressure regulators and fixed flow restrictors or mass
Ethanethiol 7.20
flow controllers capable of maintaining gas flow constant to Dimethyl Sulfide 7.76
Carbon Disulfide 8.24
61 % at the required flow rates. The gas flow rate is measured
2-Propanethiol 8.92
by any appropriate means. The supply pressure of the gas
2-methyl-2-propanethiol 10.04
delivered to the gas chromatograph must be at least 70 kPa 1-Propanethiol 10.42
Ethylmethyl sulfide 10.53
(10 psig) greater than the regulated gas at the instrument to
2-Butanethiol 12.01
compensate for the system back pressure of the flow control-
Thiophene 12.04
lers. In general, a supply pressure of 550 kPa (80 psig) is 2-methyl-1-propanethiol 12.18
Diethyl Sulfide 12.82
satisfactory.
1-Butanethiol 13.33
6.1.4 Cryogenic Column Cooling—An initial column start-
Dimethyl Disulfide 13.90
2-Methylthiophene 14.71
ing temperature below ambient temperature may be required to
3-Methylthiophene 14.84
provide complete separation of all of the sulfur gases when
Diethyl Disulfide 17.89
present in the sample. This is typically provided by adding a
Methylbenzothiophene 24.55
Methylbenzothiophene 24.66
source of either liquid carbon dioxide or liquid nitrogen,
Methylbenzothiophene 24.77
controlled through the oven temperature circuitry.
Methylbenzothiophene 24.88
6.1.5 Detector—A sulfur selective detector is used and shall
Diphenyl sulfide 28.64
meet or exceed the following specifications: (1) linearity of A
Conditions specified in 6.2.1.
10 , (2) 5 pg sulfur/s minimum detectability, (3) approximate
D5623 − 24
7. Reagents and Materials sulfur compounds in the sample. Use the highest purity
available (99 + % when possible). When purity is unknown or
7.1 Purity of Reagents—Reagent grade chemicals shall be
questionable, analyze the material by any appropriate means
used in all tests. Unless otherwise indicated, it is intended that
and use the result to provide accurate internal standard quan-
all reagents conform to the specifications of the Committee on
tities.
Analytical Reagents of the American Chemical Society where
7.1.6.1 An internal standard stock solution should be made
such specifications are available. Other grades may be used,
up in the range of 0.1 g to 1 g of the internal standard on a
provided it is first ascertained that the reagent is of sufficiently
sulfur basis to 1 kg of solvent.
high purity to permit its use without lessening the accuracy of
7.1.7 Sulfur Compound Standards—99 + % purity (if avail-
the determination.
able). Obtain pure standard material of all sulfur compounds of
7.1.1 Alkane Solvent—Such as, iso-octane (2,2,4-
interest (Warning—Sulfur compounds can be flammable and
trimethylpentane), Reagent grade, for use as solvent (diluent)
harmful or fatal when ingested or inhaled.). If purity is
in preparation of system test mixtures and for preparation of
unknown or questionable, analyze the individual standard
internal standard stock solution. (Warning—Iso-octane is
material by any appropriate means and use the result to provide
flammable and can be harmful when ingested or inhaled.)
accurate standard quantities.
7.1.2 Aromatic Solvent—Such as, toluene, Reagent grade,
7.1.8 System Test Mixture—Gravimetrically prepare a stock
for use as solvent (diluent) in preparation of system test
solution of sulfur compounds in accordance with Practice
mixtures. (Warning—Reagent grade toluene is flammable and
D4307. This solution should cover the volatility range encoun-
is toxic by inhalation, ingestion, and absorption through skin.)
tered in samples of interest; for example, dimethyl sulfide
7.1.3 Carrier Gas—Helium or nitrogen of high purity.
(;0.1 g ⁄kg), 2-propanethiol (;0.1 g ⁄kg), dimethyl disulfide
(Warning—Helium and nitrogen are compressed gases under
(;10 g ⁄kg), 3-methylthiophene (;100 g ⁄kg), and (;10 g ⁄kg)
high pressure.) Additional purification is recommended by the
benzothiophene. Prepare a working test mix solution by
use of molecular sieves or other suitable agents to remove
making a 1000:1 dilution of the stock solution in a mixture of
water, oxygen, and hydrocarbons. Available pressure must be
10 % toluene in iso-octane. Although 2-propanethiol is not
sufficient to ensure a constant carrier gas flow rate (see 6.1.3).
stable in the long term, peak asymmetry of a thiol (mercaptan)
7.1.4 Detector Gases—Hydrogen, nitrogen, air, and oxygen
is an indicator of GC system activity.
may be required as detector gases. These gases must be free of
interfering contaminants, especially sulfur compounds.
8. Sampling
(Warning—Hydrogen is an extremely flammable gas under
8.1 Appropriate sampling procedures are to be followed.
high pressure. Warning—Compressed air and oxygen are
This test method is not suitable for liquefied petroleum gases.
gases under high pressure and they support combustion.)
Volatile liquids to be analyzed by this test method shall be
7.1.5 External Standards—The sulfur compounds and ma-
sampled using the procedures outlined in Practice D4057. A
trices of external standards should be representative of the
sufficient quantity of sample should be taken for multiple
sulfur compounds and sample matrices being analyzed. Test
analyses to be performed (at least 10 g to 20 g for quantitation
...

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: D5623 − 19 D5623 − 24
Standard Test Method for
Sulfur Compounds in Light Petroleum Liquids by Gas
Chromatography and Sulfur Selective Detection
This standard is issued under the fixed designation D5623; 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 volatile sulfur-containing compounds in light petroleum liquids. This test method
is applicable to distillates, gasoline motor fuels (including those containing oxygenates) and other petroleum liquids with a final
boiling point of approximately 230 °C (450 °F) or lower at atmospheric pressure. The applicable concentration range will vary to
some extent depending on the nature of the sample and the instrumentation used; however, in most cases, the test method is
applicable to the determination of individual sulfur species at levels of 0.1 mg ⁄kg to 100 mg ⁄kg.
1.2 The test method does not purport to identify all individual sulfur components. Detector response to sulfur is linear and
essentially equimolar for all sulfur compounds within the scope (1.1) of this test method; thus both unidentified and known
individual compounds are determined. However, many sulfur compounds, for example, hydrogen sulfide and mercaptans, are
reactive and their concentration in samples may change during sampling and analysis. Coincidently, the total sulfur content of
samples is estimated from the sum of the individual compounds determined; however, this test method is not the preferred method
for determination of total sulfur.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.4 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.
1.5 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:
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D3120 Test Method for Trace Quantities of Sulfur in Light Liquid Petroleum Hydrocarbons by Oxidative Microcoulometry
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
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 July 1, 2019March 1, 2024. Published August 2019March 2024. Originally approved in 1994. Last previous edition approved in 20142019 as
D5623 – 94 (2014).D5623 – 19. DOI: 10.1520/D5623-19.10.1520/D5623-24.
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
D5623 − 24
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D4626 Practice for Calculation of Gas Chromatographic Response Factors
D5504 Test Method for Determination of Sulfur Compounds in Natural Gas and Gaseous Fuels by Gas Chromatography and
Chemiluminescence
E355 Practice for Gas Chromatography Terms and Relationships
2.2 Other Standard:
GPA 2199 Determination of Specific Sulfur Compounds by Capillary Gas Chromatography and Sulfur Chemiluminescence
Detection
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175 and Practice E355.
4. Summary of Test Method
4.1 The sample is analyzed by gas chromatography with an appropriate sulfur selective detector. Calibration is achieved by the
use of an appropriate internal or external standard. All sulfur compounds are assumed to produce equivalent response as sulfur.
4.2 Sulfur Detection—As sulfur compounds elute from the gas chromatographic column they are quantified by a sulfur selective
detector that produces a linear and equimolar response to sulfur compounds; for example, a sulfur chemiluminescence detector or
atomic emission detector used in the sulfur channel.
5. Significance and Use
5.1 Gas chromatography with sulfur selective detection provides a rapid means to identify and quantify sulfur compounds in
various petroleum feeds and products. Often these materials contain varying amounts and types of sulfur compounds. Many sulfur
compounds are odorous, corrosive to equipment, and inhibit or destroy catalysts employed in downstream processing. The ability
to speciate sulfur compounds in various petroleum liquids is useful in controlling sulfur compounds in finished products and is
frequently more important than knowledge of the total sulfur content alone.
6. Apparatus
6.1 Chromatograph—Use a gas chromatograph (GC) that has the following performance characteristics:
6.1.1 Column Temperature Programmer—The chromatograph must be capable of linear programmed temperature operation over
a range sufficient for separation of the components of interest. The programming rate must be sufficiently reproducible to obtain
retention time repeatability of 0.05 min (3 s) throughout the scope of this analysis.
6.1.2 Sample Inlet System—The sample inlet system must have variable temperature control capable of operating continuously at
a temperature up to the maximum column temperature employed. The sample inlet system must allow a constant volume of liquid
sample to be injected by means of a syringe or liquid sampling valve.
6.1.3 Carrier and Detector Gas Control—Constant flow control of carrier and detector gases is critical to optimum and consistent
analytical performance. Control is best provided by the use of pressure regulators and fixed flow restrictors or mass flow controllers
capable of maintaining gas flow constant to 61 % at the required flow rates. The gas flow rate is measured by any appropriate
means. The supply pressure of the gas delivered to the gas chromatograph must be at least 70 kPa (10 psig) greater than the
regulated gas at the instrument to compensate for the system back pressure of the flow controllers. In general, a supply pressure
of 550 kPa (80 psig) is satisfactory.
6.1.4 Cryogenic Column Cooling—An initial column starting temperature below ambient temperature may be required to provide
complete separation of all of the sulfur gases when present in the sample. This is typically provided by adding a source of either
liquid carbon dioxide or liquid nitrogen, controlled through the oven temperature circuitry.
6.1.5 Detector—A sulfur selective detector is used and shall meet or exceed the following specifications: (1) linearity of 10 , (2)
5 pg sulfur/s minimum detectability, (3) approximate equimolar response on a sulfur basis, (4) no interference or quenching from
co-eluting hydrocarbons at the GC sampling volumes used.
D5623 − 24
6.2 Column—Any column providing adequate resolution of the components of interest may be used. Using the column and typical
operating conditions as specified in 5.2.16.2.1, the retention times of some sulfur compounds will be those shown in Table 1. The
column must demonstrate a sufficiently low liquid phase bleed at high temperature, such that loss of the detector response is not
encountered while operating at the highest temperature required for the analysis.
6.2.1 Typical Operating Conditions:
6.2.1.1 Column—30 m by 0.32 mm inside diameter fused silica wall coated open tube (WCOT) column, 4 μm thick film of
methylsilicone.
6.2.1.2 Sample size—0.1 μL to 2.0 μL.
6.2.1.3 Injector—Temperature 275 °C; Split ratio: 10:1 (10 % to column).
6.2.1.4 Column Oven—10 °C for 3 min, 10 °C ⁄min to 250 °C, hold as required.
6.2.1.5 Carrier Gas—Helium, Head pressure: 70 kPa to 86 kPa (10 psig to 13 psig).
6.2.1.6 Detector—Sulfur chemiluminescence detector.
6.3 Data Acquisition:
6.3.1 Integrator—The use of an electronic integrating device or computer is recommended for determining the detector response.
The device and software must have the following capabilities: (1) graphic presentation of the chromatogram, (2) digital display
of chromatographic peak areas, (3) identification of peaks by retention time or relative retention time, or both, (4) calculation and
use of response factors, (5) internal standardization, external standardization, and data presentation.
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
TABLE 1 Typical Retention Times for Common Sulfur
A
Compounds
Sulfur Compounds Retention Time (min)
Hydrogen Sulfide 0.95
Carbonyl Sulfide 1.21
Sulfur Dioxide 1.34
Methanethiol 3.43
Ethanethiol 7.20
Dimethyl Sulfide 7.76
Carbon Disulfide 8.24
2-Propanethiol 8.92
2-methyl-2-propanethiol 10.04
1-Propanethiol 10.42
Ethylmethyl sulfide 10.53
2-Butanethiol 12.01
Thiophene 12.04
2-methyl-1-propanethiol 12.18
Diethyl Sulfide 12.82
1-Butanethiol 13.33
Dimethyl Disulfide 13.90
2-Methylthiophene 14.71
3-Methylthiophene 14.84
Diethyl Disulfide 17.89
Methylbenzothiophene 24.55
Methylbenzothiophene 24.66
Methylbenzothiophene 24.77
Methylbenzothiophene 24.88
Diphenyl sulfide 28.64
A
Conditions specified in 5.2.16.2.1.
D5623 − 24
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.
7.1.1 Alkane Solvent—Such as, iso-octane (2,2,4-trimethylpentane), Reagent grade, for use as solvent (diluent) in preparation of
system test mixtures and for preparation of internal standard stock solution. (Warning—Iso-octane is flammable and can be
harmful when ingested or inhaled.)
7.1.2 Aromatic Solvent—Such as, toluene, Reagent grade, for use as solvent (diluent) in preparation of system test mixtures.
(Warning—Reagent grade toluene is flammable and is toxic by inhalation, ingestion, and absorption through skin.)
7.1.3 Carrier Gas—Helium or nitrogen of high purity. (Warning—Helium and nitrogen are compressed gases under high
pressure.) Additional purification is recommended by the use of molecular sieves or other suitable agents to remove water, oxygen,
and hydrocarbons. Available pressure must be sufficient to ensure a constant carrier gas flow rate (see 5.1.36.1.3).
7.1.4 Detector Gases—Hydrogen, nitrogen, air, and oxygen may be required as detector gases. These gases must be free of
interfering contaminants, especially sulfur compounds. (Warning—Hydrogen is an extremely flammable gas under high pressure.
Warning—Compressed air and oxygen are gases under high pressure and they support combustion.)
7.1.5 External Standards—The sulfur compounds and matrices of external standards should be representative of the sulfur
compounds and sample matrices being analyzed. Test Methods D2622 and D3120 can be used to analyze materials for calibration
of this test method. The internal standardization procedure can also be used for generating external standards. Alternatively,
primary standards prepared as described in 6.1.47.1.4 can be used for method calibration when it is demonstrated that the matrix
does not affect calibration. Only one external standard is necessary for calibration, provided that the system performance
specification (8.39.3) is met. An external standard must contain at least one sulfur compound at a concentration level similar, for
example, within an order of magnitude to those in samples to be analyzed.
7.1.6 Internal Standards—Diphenyl sulfide, 3-chlorothiophene, and 2-bromothiophene are examples of sulfur compounds that
have been used successfully as internal standards for samples within the scope of this test method (Warning—Sulfur compounds
can be flammable and harmful or fatal when ingested or inhaled.). Any sulfur compound is suitable for use as an internal standard
provided that it is not originally present in the sample, and is resolved from other sulfur compounds in the sample. Use the highest
purity available (99 + % when possible). When purity is unknown or questionable, analyze the material by any appropriate means
and use the result to provide accurate internal standard quantities.
7.1.6.1 An internal standard stock solution should be made up in the range of 0.1 g to 1 g of the internal standard on a sulfur basis
to 1 kg of solvent.
7.1.7 Sulfur Compound Standards—99 + % purity (if available). Obtain pure standard material of all sulfur compounds of interest
(Warning—Sulfur compounds can be flammable and harmful or fatal when ingested or inhaled.). If purity is unknown or
questionable, analyze the individual standard material by any appropriate means and use the result to provide accurate standard
quantities.
7.1.8 System Test Mixture—Gravimetrically prepar
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