ASTM D5623-94(2009)
(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
SIGNIFICANCE AND USE
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 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.
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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
Designation: D5623 − 94(Reapproved 2009)
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.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method covers the determination of volatile
D2622Test Method for Sulfur in Petroleum Products by
sulfur-containing compounds in light petroleum liquids. This
Wavelength Dispersive X-ray Fluorescence Spectrometry
test method is applicable to distillates, gasoline motor fuels
D3120Test Method for Trace Quantities of Sulfur in Light
(including those containing oxygenates) and other petroleum
Liquid Petroleum Hydrocarbons by Oxidative Microcou-
liquids with a final boiling point of approximately 230°C
lometry
(450°F) or lower at atmospheric pressure. The applicable
D4057Practice for Manual Sampling of Petroleum and
concentration range will vary to some extent depending on the
Petroleum Products
natureofthesampleandtheinstrumentationused;however,in
D4307Practice for Preparation of Liquid Blends for Use as
most cases, the test method is applicable to the determination
Analytical Standards
of individual sulfur species at levels of 0.1 to 100 mg/kg.
D4626Practice for Calculation of Gas Chromatographic
1.2 The test method does not purport to identify all indi-
Response Factors
vidual sulfur components. Detector response to sulfur is linear
3. Summary of Test Method
and essentially equimolar for all sulfur compounds within the
3.1 The sample is analyzed by gas chromatography with an
scope (1.1) of this test method; thus both unidentified and
appropriatesulfurselectivedetector.Calibrationisachievedby
known individual compounds are determined. However, many
the use of an appropriate internal or external standard. All
sulfur compounds, for example, hydrogen sulfide and
sulfur compounds are assumed to produce equivalent response
mercaptans, are reactive and their concentration in samples
as sulfur.
may change during sampling and analysis. Coincidently, the
totalsulfurcontentofsamplesisestimatedfromthesumofthe
3.2 Sulfur Detection—As sulfur compounds elute from the
individualcompoundsdetermined;however,thistestmethodis
gas chromatographic column they are quantified by a sulfur
not the preferred method for determination of total sulfur.
selective detector that produces a linear and equimolar re-
sponse to sulfur compounds; for example, a sulfur chemilumi-
1.3 The values stated in SI units are to be regarded as the
nescence detector or atomic emission detector used in the
standard. The values given in parentheses are for information
sulfur channel.
only.
4. Significance and Use
1.4 This standard does not purport to address all of the
4.1 Gas chromatography with sulfur selective detection
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- provides a rapid means to identify and quantify sulfur com-
pounds in various petroleum feeds and products. Often these
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. materials contain varying amounts and types of sulfur com-
pounds. Many sulfur compounds are odorous, corrosive to
equipment, and inhibit or destroy catalysts employed in down-
stream processing.The ability to speciate sulfur compounds in
This test method is under the jurisdiction of ASTM Committee D02 on
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
D02.04.0L on Gas Chromatography Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 15, 2009. Published July 2009. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
´1
approved in 1994. Last previous edition approved in 2004 as D5623–94(2004) . Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D5623-94R09. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5623 − 94 (2009)
TABLE 1 Typical Retention Times for Common Sulfur
various petroleum liquids is useful in controlling sulfur com-
A
Compounds
pounds in finished products and is frequently more important
Sulfur Compounds Retention Time (min)
than knowledge of the total sulfur content alone.
Hydrogen Sulfide 0.95
Carbonyl Sulfide 1.21
Sulfur Dioxide 1.34
5. Apparatus
Methanethiol 3.43
5.1 Chromatograph— Use a gas chromatograph (GC) that
Ethanethiol 7.20
Dimethyl Sulfide 7.76
has the following performance characteristics:
Carbon Disulfide 8.24
5.1.1 Column Temperature Programmer —The chromato-
2-Propanethiol 8.92
graph must be capable of linear programmed temperature 2-methyl-2-propanethiol 10.04
1-Propanethiol 10.42
operation over a range sufficient for separation of the compo-
Ethylmethyl sulfide 10.53
nents of interest. The programming rate must be sufficiently
2-Butanethiol 12.01
reproducible to obtain retention time repeatability of 0.05 min Thiophene 12.04
2-methyl-1-propanethiol 12.18
(3 s) throughout the scope of this analysis.
Diethyl Sulfide 12.82
5.1.2 Sample Inlet System—The sample inlet system must
1-Butanethiol 13.33
Dimethyl Disulfide 13.90
have variable temperature control capable of operating con-
2-Methylthiophene 14.71
tinuously at a temperature up to the maximum column tem-
3-Methylthiophene 14.84
perature employed. The sample inlet system must allow a
Diethyl Disulfide 17.89
constant volume of liquid sample to be injected by means of a Methylbenzothiophene 24.55
Methylbenzothiophene 24.66
syringe or liquid sampling valve.
Methylbenzothiophene 24.77
5.1.3 Carrier and Detector Gas Control —Constant flow
Methylbenzothiophene 24.88
Diphenyl sulfide 28.64
control of carrier and detector gases is critical to optimum and
A
consistent analytical performance. Control is best provided by
Conditions specified in 5.2.1.
theuseofpressureregulatorsandfixedflowrestrictorsormass
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
5.2.1.4 Column Oven—10°Cfor3min,10°C/minto250°C,
deliveredtothegaschromatographmustbeatleast70kPa(10
hold as required.
psig) greater than the regulated gas at the instrument to
5.2.1.5 Carrier Gas—Helium, Head pressure: 70 to 86 kPa
compensate for the system back pressure of the flow control-
(10 to 13 psig).
lers. In general, a supply pressure of 550 kPa (80 psig) is
5.2.1.6 Detector—Sulfur chemiluminescence detector.
satisfactory.
5.1.4 Cryogenic Column Cooling—An initial column start- 5.3 Data Acquisition:
ingtemperaturebelowambienttemperaturemayberequiredto 5.3.1 Recorder—The use of a 0 to 1 mV recording
provide complete separation of all of the sulfur gases when potentiometer, or equivalent, with a full-scale response time of
present in the sample. This is typically provided by adding a 2 s, or less, is suitable to monitor detector signal.
source of either liquid carbon dioxide or liquid nitrogen, 5.3.2 Integrator—The use of an electronic integrating de-
controlled through the oven temperature circuitry. vice or computer is recommended for determining the detector
5.1.5 Detector—Asulfurselectivedetectorisusedandshall response. The device and software must have the following
meet or exceed the following specifications: (1) linearity of capabilities:(1)graphicpresentationofthechromatogram,( 2)
10,( 2) 5 pg sulfur/s minimum detectability, (3) approximate digital display of chromatographic peak areas, ( 3) identifica-
equimolar response on a sulfur basis, (4) no interference or tion of peaks by retention time or relative retention time, or
both, (4) calculation and use of response factors, (5) internal
quenching from co-eluting hydrocarbons at the GC sampling
volumes used. standardization, external standardization, and data presenta-
tion.
5.2 Column—Any column providing adequate resolution of
thecomponentsofinterestmaybeused.Usingthecolumnand
6. Reagents and Materials
typical operating conditions as specified in 5.2.1, the retention
times of some sulfur compounds will be those shown in Table 6.1 Purity of Reagents—Reagent grade chemicals shall be
used in all tests. Unless otherwise indicated, it is intended that
1.Thecolumnmustdemonstrateasufficientlylowliquidphase
all reagents conform to the specifications of the Committee on
bleed at high temperature, such that loss of the detector
Analytical Reagents of theAmerican Chemical Society where
response is not encountered while operating at the highest
such specifications are available. Other grades may be used,
temperature required for the analysis.
5.2.1 Typical Operating Conditions:
5.2.1.1 Column—30 m by 0.32 mm inside diameter fused
silica wall coated open tube (WCOT) column, 4-µm thick film
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
of methylsilicone.
listed by the American Chemical Society, see Annual Standards for Laboratory
5.2.1.2 Sample size— 0.1 to 2.0-µL.
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
5.2.1.3 Injector—Temperature 275°C; Split ratio: 10:1
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
(10% to column). MD.
D5623 − 94 (2009)
provided it is first ascertained that the reagent is of sufficiently unknown or questionable, analyze the individual standard
high purity to permit its use without lessening the accuracy of materialbyanyappropriatemeansandusetheresulttoprovide
the determination. accurate standard quantities.
6.1.8 System Test Mixture—Gravimetrically prepare a stock
6.1.1 Alkane Solvent— Such as, iso-octane (2,2,4-
solution of sulfur compounds in accordance with Practice
trimethylpentane), Reagent grade, for use as solvent (diluent)
D4307.Thissolutionshouldcoverthevolatilityrangeencoun-
in preparation of system test mixtures and for preparation of
tered in samples of interest; for example, dimethyl sulfide
internal standard stock solution. (Warning—Iso-octane is
(;0.1 g/kg), 2-propanethiol (;0.1 g/kg), dimethyl disulfide
flammable and can be harmful when ingested or inhaled.)
(;10 g/kg), 3-methylthiophene (;100 g/kg), and (;10 g/kg)
6.1.2 Aromatic Solvent— Such as, toluene, Reagent grade,
benzothiophene. Prepare a working test mix solution by
for use as solvent (diluent) in preparation of system test
making a 1000:1 dilution of the stock solution in a mixture of
mixtures.(Warning—Reagentgradetolueneisflammableand
10% toluene in iso-octane. Although 2-propanethiol is not
is toxic by inhalation, ingestion, and absorption through skin.)
stable in the long term, peak asymmetry of a thiol (mercaptan)
6.1.3 Carrier Gas— Helium or nitrogen of high purity.
is an indicator of GC system activity.
(Warning—Helium and nitrogen are compressed gases under
high pressure.)Additional purification is recommended by the
7. Sampling
use of molecular sieves or other suitable agents to remove
7.1 Appropriate sampling procedures are to be followed.
water, oxygen, and hydrocarbons. Available pressure must be
This test method is not suitable for liquefied petroleum gases.
sufficient to ensure a constant carrier gas flow rate (see 5.1.3).
Volatile liquids to be analyzed by this test method shall be
6.1.4 Detector Gases—Hydrogen, nitrogen, air, and oxygen
sampled using the procedures outlined in Practice D4057.A
may be required as detector gases.These gases must be free of
sufficient quantity of sample should be taken for multiple
interfering contaminants, especially sulfur compounds.
analysestobeperformed(atleast10to20gforquantitationby
(Warning—Hydrogen is an extremely flammable gas under
internalstandardization).Storeallsamplesandstandardblends
high pressure. Warning—Compressed air and oxygen are
at a temperature of 7 to 15°C (45 to 60°F). Do not open the
gases under high pressure and they support combustion.)
sample or standard container at temperatures above 15°C
6.1.5 External Standards—The sulfur compounds and ma-
(60°F).
trices of external standards should be representative of the
sulfur compounds and sample matrices being analyzed. Test
8. Preparation of Apparatus
Methods D2622 and D3120 can be used to analyze materials
8.1 Chromatograph— Place in service in accordance with
for calibration of this test method.The internal standardization
the manufacturer’s instructions. Typical chromatograph and
procedure can also be used for generating external standards.
detector operating conditions are shown in 5.2.1.
Alternatively, primary standards prepared as described in 6.1.4
canbeusedformethodcalibrationwhenitisdemonstratedthat 8.2 Detector—Place in service in accordance with the
the matrix does not affect calibration. Only one external manufacturer’s instructions. After sufficient equilibration time
standard is necessary for calibration, provided that the system (for example, 5 to 10 min), adjust the detector output signal or
performance specification (8.3) is met. An external standard integrator input signal to approximately zero. Monitor the
must contain at least one sulfur compound at a concentration signal for several minutes to verify compliance with the
level similar, for example, within an order of magnitude to specified signal noise and drift.
those in samples to be analyzed.
8.3 System Performance Specification— The inlet system
6.1.6 Internal Standards—Diphenyl sulfide,
should be evaluated for compatibility with trace quantities of
3-chlorothiophene, and 2-bromothiophene are examples of
reactive sulfur compounds. Inject and analyze a suitable
sulfur compounds that have been used successfully as internal
amount (for example, 0.1 to 2.0-µL) of the system test mixture
standards for samples within the scope of this test method
(6.1.8).All sulfur compounds should give essentially equimo-
(Warning—Sulfur compounds can be flammable and harmful
lar response and should exhibit symmetrical peak shapes.
or fatal when ingested or inhaled.). Any sulfur compound is
Relative response factors should be calculated for each sulfur
suitable for use as an internal standard provided that it is not
compound in the test mixture (relative to a referenced compo-
originally present in the sample, and is resolved from other
nent) in accordance with Practice D4626 or Eq 1:
sulf
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