ASTM D5623-94(1999)e1
(Test Method)Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection
Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection
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 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 the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
An American National Standard
e1
Designation: D 5623 – 94 (Reapproved 1999)
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 D 5623; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Warning statements were placed in the text in November 1999.
1. Scope D 3120 Test Method for Trace Quantities of Sulfur in Light
Liquid Petroleum Hydrocarbons by Oxidative Microcou-
1.1 This test method covers the determination of volatile
lometry
sulfur-containing compounds in light petroleum liquids. This
D 4057 Practice for Manual Sampling of Petroleum and
test method is applicable to distillates, gasoline motor fuels
Petroleum Products
(including those containing oxygenates) and other petroleum
D 4307 Practice for Preparation of Liquid Blends for Use as
liquids with a final boiling point of approximately 230°C
Analytical Standards
(450°F) or lower at atmospheric pressure. The applicable
D 4626 Practice for Calculation of Gas Chromatographic
concentration range will vary to some extent depending on the
Response Factors
nature of the sample and the instrumentation used; however, in
most cases, the test method is applicable to the determination
3. Summary of Test Method
of individual sulfur species at levels of 0.1 to 100 mg/kg.
3.1 The sample is analyzed by gas chromatography with an
1.2 The test method does not purport to identify all indi-
appropriate sulfur selective detector. Calibration is achieved by
vidual sulfur components. Detector response to sulfur is linear
the use of an appropriate internal or external standard. All
and essentially equimolar for all sulfur compounds within the
sulfur compounds are assumed to produce equivalent response
scope (1.1) of this test method; thus both unidentified and
as sulfur.
known individual compounds are determined. However, many
3.2 Sulfur Detection—As sulfur compounds elute from the
sulfur compounds, for example, hydrogen sulfide and mercap-
gas chromatographic column they are quantified by a sulfur
tans, are reactive and their concentration in samples may
selective detector that produces a linear and equimolar re-
change during sampling and analysis. Coincidently, the total
sponse to sulfur compounds; for example sulfur chemilumi-
sulfur content of samples is estimated from the sum of the
nescence detector or atomic emission detector (AED ) used in
individual compounds determined; however, this test method is
the sulfur channel.
not the preferred method for determination of total sulfur.
1.3 The values stated in SI units are to be regarded as the
4. Significance and Use
standard. The values given in parentheses are for information
4.1 Gas chromatography with sulfur selective detection
only.
provides a rapid means to identify and quantify sulfur com-
1.4 This standard does not purport to address all of the
pounds in various petroleum feeds and products. Often these
safety concerns, if any, associated with its use. It is the
materials contain varying amounts and types of sulfur com-
responsibility of the user of this standard to establish appro-
pounds. Many sulfur compounds are odorous, corrosive to
priate safety and health practices and determine the applica-
equipment, and inhibit or destroy catalysts employed in down-
bility of regulatory limitations prior to use.
stream processing. The ability to speciate sulfur compounds in
2. Referenced Documents various petroleum liquids is useful in controlling sulfur com-
pounds in finished products and is frequently more important
2.1 ASTM Standards:
than knowledge of the total sulfur content alone.
D 2622 Test Method for Sulfur in Petroleum Products
(X-Ray Spectrographic Method)
5. Apparatus
5.1 Chromatograph—Use a gas chromatograph (GC) that
has the following performance characteristics:
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.04.0L on Gas Chromatography. Annual Book of ASTM Standards, Vol 05.02.
Current edition approved Dec. 15, 1994. Published February 1995. The AED is manufactured by Hewlett-Packard Co., 2850 Centerville Rd.,
Annual Book of ASTM Standards, Vol 05.01. Wilmington, DE 19808-1610.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
e1
D 5623 – 94 (1999)
5.1.1 Column Temperature Programmer—The chromato- 5.3.1 Recorder—The use ofa0to1mV recording poten-
graph must be capable of linear programmed temperature tiometer, or equivalent, with a full-scale response time of 2 s,
operation over a range sufficient for separation of the compo- or less, is suitable to monitor detector signal.
nents of interest. The programming rate must be sufficiently 5.3.2 Integrator—The use of an electronic integrating de-
reproducible to obtain retention time repeatability of 0.05 min vice or computer is recommended for determining the detector
(3 s) throughout the scope of this analysis. response. The device and software must have the following
capabilities: (a) graphic presentation of the chromatogram, (b)
5.1.2 Sample Inlet System—The sample inlet system must
digital display of chromatographic peak areas, (c) identification
have variable temperature control capable of operating con-
of peaks by retention time or relative retention time, or both,
tinuously at a temperature up to the maximum column tem-
(d) calculation and use of response factors, (e) internal stan-
perature employed. The sample inlet system must allow a
dardization, external standardization, and data presentation.
constant volume of liquid sample to be injected by means of a
syringe or liquid sampling valve.
6. Reagents and Materials
5.1.3 Carrier and Detector Gas Control—Constant flow
6.1 Purity of Reagents—Reagent grade chemicals shall be
control of carrier and detector gases is critical to optimum and
used in all tests. Unless otherwise indicated, it is intended that
consistent analytical performance. Control is best provided by
all reagents conform to the specifications of the Committee on
the use of pressure regulators and fixed flow restrictors or mass
Analytical Reagents of the American Chemical Society where
flow controllers capable of maintaining gas flow constant to
such specifications are available. Other grades may be used,
61 % at the required flow rates. The gas flow rate is measured
provided it is first ascertained that the reagent is of sufficiently
by any appropriate means. The supply pressure of the gas
high purity to permit its use without lessening the accuracy of
delivered to the gas chromatograph must be at least 70 kPa (10
the determination.
psig) greater than the regulated gas at the instrument to
6.1.1 Alkane Solvent—Such as, iso-octane (2,2,4-
compensate for the system back pressure of the flow control-
trimethylpentane), Reagent grade, for use as solvent (diluent)
lers. In general, a supply pressure of 550 kPa (80 psig) is
in preparation of system test mixtures and for preparation of
satisfactory.
internal standard stock solution (Warning—Iso-octane is
5.1.4 Cryogenic Column Cooling—An initial column start-
flammable and can be harmful when ingested or inhaled.).
ing temperature below ambient temperature may be required to
6.1.2 Aromatic Solvent—Such as, toluene, Reagent grade,
provide complete separation of all of the sulfur gases when
for use as solvent (diluent) in preparation of system test
present in the sample. This is typically provided by adding a
mixtures (Warning—Reagent grade toluene is flammable and
source of either liquid carbon dioxide or liquid nitrogen,
is toxic by inhalation, ingestion, and absorption through skin.).
controlled through the oven temperature circuitry.
6.1.3 Carrier Gas—Helium or nitrogen of high purity
5.1.5 Detector—A sulfur selective detector is used and shall
(Warning—Helium and nitrogen are compressed gases under
meet or exceed the following specifications: (a) linearity of
high pressure.). Additional purification is recommended by the
10 ,(b) 5 pg sulfur/s minimum detectability, (c) approximate
use of molecular sieves or other suitable agents to remove
equimolar response on a sulfur basis, (d) no interference or
water, oxygen, and hydrocarbons. Available pressure must be
quenching from co-eluting hydrocarbons at the GC sampling
sufficient to ensure a constant carrier gas flow rate (see 5.1.3).
volumes used.
6.1.4 Detector Gases—Hydrogen, nitrogen, air, and oxygen
5.2 Column—Any column providing adequate resolution of
may be required as detector gases. These gases must be free of
the components of interest may be used. Using the column and
interferring contaminants, especially sulfur compounds.
typical operating conditions as specified in 5.2.1, the retention
(Warning—Hydrogen is an extremely flammable gas under
times of some sulfur compounds will be those shown in Table
high pressure. Warning—Compressed air and oxygen are
1. The column must demonstrate a sufficiently low liquid phase
gases under high pressure and they support combustion.).
bleed at high temperature, such that loss of the detector
6.1.5 External Standards—The sulfur compounds and ma-
response is not encountered while operating at the highest
trices of external standards should be representative of the
temperature required for the analysis.
sulfur compounds and sample matrices being analyzed. Test
5.2.1 Typical Operating Conditions:
Methods D 2622 and D 3120 can be used to analyze materials
5.2.1.1 Column—30 m by 0.32 mm inside diameter fused for calibration of this test method. The internal standardization
silica wall coated open tube (WCOT) column, 4-μm thick film
procedure can also be used for generating external standards.
of methylsilicone. Alternatively, primary standards prepared as described in 6.1.4
can be used for method calibration when it is demonstrated that
5.2.1.2 Sample size—0.1 to 2.0-μL.
the matrix does not affect calibration. Only one external
5.2.1.3 Injector—Temperature 275°C; Split ratio: 10:1
standard is necessary for calibration, provided that the system
(10 % to column).
5.2.1.4 Column Oven—10°C for 3 min, 10°C/min to 250°C,
hold as required.
Reagent Chemicals, American Chemical Society Specifications, American
5.2.1.5 Carrier Gas—Helium, Head pressure: 70 to 86 kPa
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
(10 to 13 psig).
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
5.2.1.6 Detector—Sulfur chemiluminescence detector.
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
5.3 Data Acquisition: MD.
e1
D 5623 – 94 (1999)
performance specification (8.3) is met. An external standard signal for several minutes to verify compliance with the
must contain at least one sulfur compound at a concentration specified signal noise and drift.
level similar, for example, within an order of magnitude to 8.3 System Performance Specification—The inlet system
those in samples to be analyzed. should be evaluated for compatibility with trace quantities of
6.1.6 Internal Standards—Diphenyl sulfide, reactive sulfur compounds. Inject and analyze a suitable
3-chlorothiophene, and 2-bromothiophene are examples of amount (for example, 0.1 to 2.0-μL) of the system test mixture
sulfur compounds that have been used successfully as internal (6.1.8). All sulfur compounds should give essentially equimo-
standards for samples within the scope of this test method lar response and should exhibit symmetrical peak shapes.
(Warning—Sulfur compounds can be flammable and harmful Relative response factors should be calculated for each sulfur
or fatal when ingested or inhaled.). Any sulfur compound is compound in the test mixture (relative to a referenced compo-
suitable for use as an internal standard provided that it is not nent) in accordance with Practice D 4626 or Eq 1:
originally present in the sample, and is resolved from other
C 3 A
n r
R 5 (1)
sulfur compounds in the sample. Use the highest purity rn
C 3 A
r n
available (99 + % when possible). When purity is unknown or
questionable, analyze the material by any appropriate means
where:
and use the result to provide accurate internal standard quan-
R = relative response factor for a given sulfur compound,
rn
tities.
C = concentration of the sulfur compound as sulfur,
n
6.1.6.1 An internal standard stock solution should be made
A = peak area of the sulfur compound,
n
up in the range of 0.1 to1gofthe internal standard on a sulfur
C = concentration of referenced sulfur standard as sulfur,
r
basis to 1 kg of solvent.
and
6.1.7 Sulfur Compound Standards—99 + % purity (if avail-
A = peak area of the referenced sulfur standard.
r
able). Obtain pure standard material of all sulfur compounds of
The relative response factor (R ) for each sulfur compound
rn
interest (Warning—Sulfur compounds can be flammable and
should not deviate from unity by more than 610 %. Deviation
harmful or fatal when ingested or inhaled.). If purity is
of response by more than 610 % or severe peak asymmetry
unknown or questionable, analyze the individual standard
indicates a chromatography or detector problem that must be
material by any appropriate means and use the result to provide
corrected to ensure proper selectivity, sensitivity, linearity, and
accurate standard quantities.
integrity of the system. If necessary, optimize the system
6.1.8 System Test Mixture—Gravimetrically prepare a stock
according to instructions from the manufacturers.
solution of sulfur compounds in accordance with Practice
D 4307. This solution should cover the volatility range encoun-
9. Procedure
tered in samples of interest; for example, dimethyl sulfide
9.1 A list of typical apparatus and conditions is provided in
(;0.1 g/kg), 2-propanethiol (;0.1 g/kg), dimethyl disulfide
5.2.1. Table 2 provides a listing of the retention times for
(;10 g/kg), 3-methylthiophene (;100 g/kg), and (;10 g/kg)
common sulfur compounds that are typical for the column and
benzothiophene. Prepare a working test mix solution by
conditions specified in 5.2.1. Whenever possible, the retention
making a 1000:1 dilution of the stock solution in a mixture of
times of sulfur compounds of interest should be determined
10 % toluene in iso-octane. Although 2-propanethiol is not
experimentally. Fig. 1 shows a
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.