ASTM D5623-94(2004)e1

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An American National Standard
e1
Designation:D5623–94 (Reapproved 2004)
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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Footnote 4 no longer applied, and it was removed editorially in June 2004.
1. Scope 2. Referenced Documents
1.1 This test method covers the determination of volatile 2.1 ASTM Standards:
sulfur-containing compounds in light petroleum liquids. This D2622 Test Method for Sulfur in Petroleum Products
test method is applicable to distillates, gasoline motor fuels (X-Ray Spectrographic Method)
(including those containing oxygenates) and other petroleum D3120 Test Method forTrace Quantities of Sulfur in Light
liquids with a final boiling point of approximately 230°C Liquid Petroleum Hydrocarbons by Oxidative Microcou-
(450°F) or lower at atmospheric pressure. The applicable lometry
concentration range will vary to some extent depending on the D4057 Practice for Manual Sampling of Petroleum and
natureofthesampleandtheinstrumentationused;however,in Petroleum Products
most cases, the test method is applicable to the determination D4307 PracticeforPreparationofLiquidBlendsforUseas
of individual sulfur species at levels of 0.1 to 100 mg/kg. Analytical Standards
1.2 The test method does not purport to identify all indi- D4626 Practice for Calculation of Gas Chromatographic
vidual sulfur components. Detector response to sulfur is linear Response Factors
and essentially equimolar for all sulfur compounds within the
3. Summary of Test Method
scope (1.1) of this test method; thus both unidentified and
known individual compounds are determined. However, many 3.1 The sample is analyzed by gas chromatography with an
appropriatesulfurselectivedetector.Calibrationisachievedby
sulfur compounds, for example, hydrogen sulfide and mercap-
tans, are reactive and their concentration in samples may the use of an appropriate internal or external standard. All
change during sampling and analysis. Coincidently, the total sulfur compounds are assumed to produce equivalent response
as sulfur.
sulfur content of samples is estimated from the sum of the
individualcompoundsdetermined;however,thistestmethodis 3.2 Sulfur Detection—As sulfur compounds elute from the
gas chromatographic column they are quantified by a sulfur
not the preferred method for determination of total sulfur.
1.3 The values stated in SI units are to be regarded as the selective detector that produces a linear and equimolar re-
sponse to sulfur compounds; for example, a sulfur chemilumi-
standard. The values given in parentheses are for information
only. nescence detector or atomic emission detector used in the
sulfur channel.
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
4. Significance and Use
responsibility of the user of this standard to establish appro-
4.1 Gas chromatography with sulfur selective detection
priate safety and health practices and determine the applica-
provides a rapid means to identify and quantify sulfur com-
bility of regulatory limitations prior to use.
pounds in various petroleum feeds and products. Often these
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 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
D02.04 on Hydrocarbon Analysis. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved May 1, 2004. Published June 2004. Originally Standards volume information, refer to the standard’s Document Summary page on
e1
approved in 1994. Last previous edition approved in 1999 as D5623–94(1999) . the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D5623–94 (2004)
various petroleum liquids is useful in controlling sulfur com- 5.2.1.4 Column Oven—10°Cfor3min,10°C/minto250°C,
pounds in finished products and is frequently more important hold as required.
than knowledge of the total sulfur content alone. 5.2.1.5 Carrier Gas—Helium, Head pressure: 70 to 86 kPa
(10 to 13 psig).
5.2.1.6 Detector—Sulfur chemiluminescence detector.
5. Apparatus
5.3 Data Acquisition:
5.1 Chromatograph—Use a gas chromatograph (GC) that
5.3.1 Recorder—Theuseofa0to1mV recording poten-
has the following performance characteristics:
tiometer, or equivalent, with a full-scale response time of 2 s,
5.1.1 Column Temperature Programmer—The chromato-
or less, is suitable to monitor detector signal.
graph must be capable of linear programmed temperature
5.3.2 Integrator—The use of an electronic integrating de-
operation over a range sufficient for separation of the compo-
vice or computer is recommended for determining the detector
nents of interest. The programming rate must be sufficiently
response. The device and software must have the following
reproducible to obtain retention time repeatability of 0.05 min
capabilities: (1) graphic presentation of the chromatogram, (2)
(3 s) throughout the scope of this analysis.
digital display of chromatographic peak areas, (3) identifica-
5.1.2 Sample Inlet System—The sample inlet system must
tion of peaks by retention time or relative retention time, or
have variable temperature control capable of operating con-
both, (4) calculation and use of response factors, (5) internal
tinuously at a temperature up to the maximum column tem-
standardization, external standardization, and data presenta-
perature employed. The sample inlet system must allow a
tion.
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
theuseofpressureregulatorsandfixedflowrestrictorsormass
Analytical Reagents of theAmerican 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
deliveredtothegaschromatographmustbeatleast70kPa(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.)
ingtemperaturebelowambienttemperaturemayberequiredto
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—Reagentgradetolueneisflammableand
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—Asulfurselectivedetectorisusedandshall
(Warning—Helium and nitrogen are compressed gases under
meet or exceed the following specifications: (1) linearity of
high pressure.)Additional purification is recommended by the
10,(2) 5 pg sulfur/s minimum detectability, (3) approximate
use of molecular sieves or other suitable agents to remove
equimolar response on a sulfur basis, (4) 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
thecomponentsofinterestmaybeused.Usingthecolumnand
interfering 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.Thecolumnmustdemonstrateasufficientlylowliquidphase
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:
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.
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D5623–94 (2004)
Methods D2622 and D3120 can be used to analyze materials 8. Preparation of Apparatus
for calibration of this test method.The internal standardization
8.1 Chromatograph—Place in service in accordance with
procedure can also be used for generating external standards.
the manufacturer’s instructions. Typical chromatograph and
Alternatively, primary standards prepared as described in 6.1.4
detector operating conditions are shown in 5.2.1.
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
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 D4626 or Eq 1:
originally present in the sample, and is resolved from other
sulfur compounds in the sample. Use the highest purity C 3 A
n r
R 5 (1)
rn
C 3 A
available (99+% when possible). When purity is unknown or
r n
questionable, analyze the material by any appropriate means
and use the result to provide accurate internal standard quan-
where:
tities.
R = relativeresponsefactorforagivensulfurcompound,
rn
6.1.6.1 An internal standard stock solution should be made
C = concentration of the sulfur compound as sulfur,
n
upintherangeof0.1to1goftheinternalstandardonasulfur A = peak area of the sulfur compound,
n
C = concentration of referenced sulfur standard as sulfur,
basis to 1 kg of solvent.
r
and
6.1.7 Sulfur Compound Standards—99+% purity (if avail-
A = peak area of the referenced sulfur standard.
r
able).Obtainpurestandardmaterialofallsulfurcompoundsof
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
materialbyanyappropriatemeansandusetheresulttoprovide
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
D4307.Thissolutionshouldcoverthevolatilityrangeencoun-
9. Procedure
tered in samples of interest; for example, dimethyl sulfide
9.1 Alist 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 compou
...