1、Designation: D 5623 94 (Reapproved 2009)Standard Test Method forSulfur Compounds in Light Petroleum Liquids by GasChromatography and Sulfur Selective Detection1This standard is issued under the fixed designation D 5623; the number immediately following the designation indicates the year oforiginal a
2、doption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of volatilesulfur-containin
3、g compounds in light petroleum liquids. Thistest method is applicable to distillates, gasoline motor fuels(including those containing oxygenates) and other petroleumliquids with a final boiling point of approximately 230C(450F) or lower at atmospheric pressure. The applicableconcentration range will
4、 vary to some extent depending on thenature of the sample and the instrumentation used; however, inmost cases, the test method is applicable to the determinationof individual sulfur species at levels of 0.1 to 100 mg/kg.1.2 The test method does not purport to identify all indi-vidual sulfur componen
5、ts. Detector response to sulfur is linearand essentially equimolar for all sulfur compounds within thescope (1.1) of this test method; thus both unidentified andknown individual compounds are determined. However, manysulfur compounds, for example, hydrogen sulfide and mercap-tans, are reactive and t
6、heir concentration in samples maychange during sampling and analysis. Coincidently, the totalsulfur content of samples is estimated from the sum of theindividual compounds determined; however, this test method isnot the preferred method for determination of total sulfur.1.3 The values stated in SI u
7、nits are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health p
8、ractices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2622 Test Method for Sulfur in Petroleum Products byWavelength Dispersive X-ray Fluorescence SpectrometryD 3120 Test Method for Trace Quantities of Sulfur in LightLiquid Petr
9、oleum Hydrocarbons by Oxidative Microcou-lometryD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD 4626 Practice for Calculation of Gas ChromatographicResponse Factors3. Summary of Test Method3.1 The
10、sample is analyzed by gas chromatography with anappropriate sulfur selective detector. Calibration is achieved bythe use of an appropriate internal or external standard. Allsulfur compounds are assumed to produce equivalent responseas sulfur.3.2 Sulfur DetectionAs sulfur compounds elute from thegas
11、chromatographic column they are quantified by a sulfurselective detector that produces a linear and equimolar re-sponse to sulfur compounds; for example, a sulfur chemilumi-nescence detector or atomic emission detector used in thesulfur channel.4. Significance and Use4.1 Gas chromatography with sulf
12、ur selective detectionprovides a rapid means to identify and quantify sulfur com-pounds in various petroleum feeds and products. Often thesematerials contain varying amounts and types of sulfur com-pounds. Many sulfur compounds are odorous, corrosive toequipment, and inhibit or destroy catalysts emp
13、loyed in down-stream processing. The ability to speciate sulfur compounds invarious petroleum liquids is useful in controlling sulfur com-pounds in finished products and is frequently more importantthan knowledge of the total sulfur content alone.5. Apparatus5.1 ChromatographUse a gas chromatograph
14、(GC) thathas the following performance characteristics:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved April 15, 2009. Published July
15、 2009. Originallyapproved in 1994. Last previous edition approved in 2004 as D 562394(2004)1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document
16、Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.1 Column Temperature ProgrammerThe chromato-graph must be capable of linear programmed temperatureoperation over a range sufficient for separation of
17、 the compo-nents of interest. The programming rate must be sufficientlyreproducible to obtain retention time repeatability of 0.05 min(3 s) throughout the scope of this analysis.5.1.2 Sample Inlet SystemThe sample inlet system musthave variable temperature control capable of operating con-tinuously
18、at a temperature up to the maximum column tem-perature employed. The sample inlet system must allow aconstant volume of liquid sample to be injected by means of asyringe or liquid sampling valve.5.1.3 Carrier and Detector Gas ControlConstant flowcontrol of carrier and detector gases is critical to o
19、ptimum andconsistent analytical performance. Control is best provided bythe use of pressure regulators and fixed flow restrictors or massflow controllers capable of maintaining gas flow constant to61 % at the required flow rates. The gas flow rate is measuredby any appropriate means. The supply pres
20、sure of the gasdelivered to the gas chromatograph must be at least 70 kPa (10psig) greater than the regulated gas at the instrument tocompensate for the system back pressure of the flow control-lers. In general, a supply pressure of 550 kPa (80 psig) issatisfactory.5.1.4 Cryogenic Column CoolingAn i
21、nitial column start-ing temperature below ambient temperature may be required toprovide complete separation of all of the sulfur gases whenpresent in the sample. This is typically provided by adding asource of either liquid carbon dioxide or liquid nitrogen,controlled through the oven temperature ci
22、rcuitry.5.1.5 DetectorAsulfur selective detector is used and shallmeet or exceed the following specifications: (1) linearity of104,(2) 5 pg sulfur/s minimum detectability, (3) approximateequimolar response on a sulfur basis, (4) no interference orquenching from co-eluting hydrocarbons at the GC samp
23、lingvolumes used.5.2 ColumnAny column providing adequate resolution ofthe components of interest may be used. Using the column andtypical operating conditions as specified in 5.2.1, the retentiontimes of some sulfur compounds will be those shown in Table1. The column must demonstrate a sufficiently
24、low liquid phasebleed at high temperature, such that loss of the detectorresponse is not encountered while operating at the highesttemperature required for the analysis.5.2.1 Typical Operating Conditions:5.2.1.1 Column30 m by 0.32 mm inside diameter fusedsilica wall coated open tube (WCOT) column, 4
25、-m thick filmof methylsilicone.5.2.1.2 Sample size0.1 to 2.0-L.5.2.1.3 InjectorTemperature 275C; Split ratio: 10:1(10 % to column).5.2.1.4 Column Oven10C for 3 min, 10C/min to 250C,hold as required.5.2.1.5 Carrier GasHelium, Head pressure: 70 to 86 kPa(10 to 13 psig).5.2.1.6 DetectorSulfur chemilumi
26、nescence detector.5.3 Data Acquisition:5.3.1 RecorderTheuseofa0to1mVrecording poten-tiometer, or equivalent, with a full-scale response time of 2 s,or less, is suitable to monitor detector signal.5.3.2 IntegratorThe use of an electronic integrating de-vice or computer is recommended for determining
27、the detectorresponse. The device and software must have the followingcapabilities: (1) graphic presentation of the chromatogram, (2)digital display of chromatographic peak areas, (3) identifica-tion of peaks by retention time or relative retention time, orboth, (4) calculation and use of response fa
28、ctors, (5) internalstandardization, external standardization, and data presenta-tion.6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytic
29、al Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.1.1 Alkane SolventSuch as, iso-octane (
30、2,2,4-trimethylpentane), Reagent grade, for use as solvent (diluent)in preparation of system test mixtures and for preparation ofinternal standard stock solution. (WarningIso-octane isflammable and can be harmful when ingested or inhaled.)6.1.2 Aromatic SolventSuch as, toluene, Reagent grade,for use
31、 as solvent (diluent) in preparation of system testmixtures. (WarningReagent grade toluene is flammable andis toxic by inhalation, ingestion, and absorption through skin.)6.1.3 Carrier GasHelium or nitrogen of high purity.(WarningHelium and nitrogen are compressed gases underhigh pressure.) Addition
32、al purification is recommended by theuse of molecular sieves or other suitable agents to removewater, oxygen, and hydrocarbons. Available pressure must besufficient to ensure a constant carrier gas flow rate (see 5.1.3).6.1.4 Detector GasesHydrogen, nitrogen, air, and oxygenmay be required as detect
33、or gases. These gases must be free ofinterfering contaminants, especially sulfur compounds.(WarningHydrogen is an extremely flammable gas underhigh pressure. WarningCompressed air and oxygen aregases under high pressure and they support combustion.)6.1.5 External StandardsThe sulfur compounds and ma
34、-trices of external standards should be representative of thesulfur compounds and sample matrices being analyzed. TestMethods D 2622 and D 3120 can be used to analyze materialsfor calibration of this test method. The internal standardizationprocedure can also be used for generating external standard
35、s.Alternatively, primary standards prepared as described in 6.1.4can be used for method calibration when it is demonstrated thatthe matrix does not affect calibration. Only one external3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggest
36、ions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D 5623 94 (2009)2standard is nec
37、essary for calibration, provided that the systemperformance specification (8.3) is met. An external standardmust contain at least one sulfur compound at a concentrationlevel similar, for example, within an order of magnitude tothose in samples to be analyzed.6.1.6 Internal StandardsDiphenyl sulfide,
38、3-chlorothiophene, and 2-bromothiophene are examples ofsulfur compounds that have been used successfully as internalstandards for samples within the scope of this test method(WarningSulfur compounds can be flammable and harmfulor fatal when ingested or inhaled.). Any sulfur compound issuitable for u
39、se as an internal standard provided that it is notoriginally present in the sample, and is resolved from othersulfur compounds in the sample. Use the highest purityavailable (99 + % when possible). When purity is unknown orquestionable, analyze the material by any appropriate meansand use the result
40、 to provide accurate internal standard quan-tities.6.1.6.1 An internal standard stock solution should be madeup in the range of 0.1 to1goftheinternal standard on a sulfurbasis to 1 kg of solvent.6.1.7 Sulfur Compound Standards99 + % purity (if avail-able). Obtain pure standard material of all sulfur
41、 compounds ofinterest (WarningSulfur compounds can be flammable andharmful or fatal when ingested or inhaled.). If purity isunknown or questionable, analyze the individual standardmaterial by any appropriate means and use the result to provideaccurate standard quantities.6.1.8 System Test MixtureGra
42、vimetrically prepare a stocksolution of sulfur compounds in accordance with PracticeD 4307.This solution should cover the volatility range encoun-tered in samples of interest; for example, dimethyl sulfide(;0.1 g/kg), 2-propanethiol (;0.1 g/kg), dimethyl disulfide(;10 g/kg), 3-methylthiophene (;100
43、g/kg), and (;10 g/kg)benzothiophene. Prepare a working test mix solution bymaking a 1000:1 dilution of the stock solution in a mixture of10 % toluene in iso-octane. Although 2-propanethiol is notstable in the long term, peak asymmetry of a thiol (mercaptan)is an indicator of GC system activity.7. Sa
44、mpling7.1 Appropriate sampling procedures are to be followed.This test method is not suitable for liquefied petroleum gases.Volatile liquids to be analyzed by this test method shall besampled using the procedures outlined in Practice D 4057.Asufficient quantity of sample should be taken for multiple
45、analyses to be performed (at least 10 to 20 g for quantitation byinternal standardization). Store all samples and standard blendsat a temperature of 7 to 15C (45 to 60F). Do not open thesample or standard container at temperatures above 15C(60F).8. Preparation of Apparatus8.1 ChromatographPlace in s
46、ervice in accordance withthe manufacturers instructions. Typical chromatograph anddetector operating conditions are shown in 5.2.1.8.2 DetectorPlace in service in accordance with themanufacturers instructions. After sufficient equilibration time(for example, 5 to 10 min), adjust the detector output
47、signal orintegrator input signal to approximately zero. Monitor thesignal for several minutes to verify compliance with thespecified signal noise and drift.8.3 System Performance SpecificationThe inlet systemshould be evaluated for compatibility with trace quantities ofreactive sulfur compounds. Inj
48、ect and analyze a suitableamount (for example, 0.1 to 2.0-L) of the system test mixture(6.1.8). All sulfur compounds should give essentially equimo-lar response and should exhibit symmetrical peak shapes.Relative response factors should be calculated for each sulfurcompound in the test mixture (rela
49、tive to a referenced compo-nent) in accordance with Practice D 4626 or Eq 1:Rrn5Cn3 ArCr3 An(1)where:Rrn= relative response factor for a given sulfur compound,Cn= concentration of the sulfur compound as sulfur,An= peak area of the sulfur compound,Cr= concentration of referenced sulfur standard as sulfur,andAr= peak area of the referenced sulfur standard.The relative response factor (Rrn) for each sulfur compoundshould not deviate from unity by more than 610 %. Deviationof response by more than 610 % or severe peak asymmetryindicates
