1、Designation: D 5623 94 (Reapproved 2004)e1An American National StandardStandard 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
2、indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEFootnote 4 no longer applied, and it was re
3、moved editorially in June 2004.1. Scope1.1 This test method covers the determination of volatilesulfur-containing compounds in light petroleum liquids. Thistest method is applicable to distillates, gasoline motor fuels(including those containing oxygenates) and other petroleumliquids with a final bo
4、iling point of approximately 230C(450F) or lower at atmospheric pressure. The applicableconcentration range will 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 specie
5、s at levels of 0.1 to 100 mg/kg.1.2 The test method does not purport to identify all indi-vidual sulfur components. 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
6、are determined. However, manysulfur compounds, for example, hydrogen sulfide and mercap-tans, are reactive and their concentration in samples maychange during sampling and analysis. Coincidently, the totalsulfur content of samples is estimated from the sum of theindividual compounds determined; howe
7、ver, this test method isnot the preferred method for determination of total sulfur.1.3 The values stated in SI units 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
8、with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices 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(X-Ray Spectr
9、ographic Method)D 3120 Test Method for Trace Quantities of Sulfur in LightLiquid Petroleum 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 fo
10、r Calculation of Gas ChromatographicResponse Factors3. Summary of Test Method3.1 The 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 eq
11、uivalent responseas sulfur.3.2 Sulfur DetectionAs sulfur compounds elute from thegas 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 detec
12、tor used in thesulfur channel.4. Significance and Use4.1 Gas chromatography with sulfur 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 sulf
13、ur compounds are odorous, corrosive toequipment, and inhibit or destroy catalysts employed in down-stream processing. The ability to speciate sulfur compounds in1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of S
14、ubcommitteeD02.04 on Hydrocarbon Analysis.Current edition approved May 1, 2004. Published June 2004. Originallyapproved in 1994. Last previous edition approved in 1999 as D 562394(1999)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service
15、astm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.various petroleum liquids is useful in controlling sulfur
16、com-pounds in finished products and is frequently more importantthan knowledge of the total sulfur content alone.5. Apparatus5.1 ChromatographUse a gas chromatograph (GC) thathas the following performance characteristics:5.1.1 Column Temperature ProgrammerThe chromato-graph must be capable of linear
17、 programmed temperatureoperation over a range sufficient for separation of 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
18、 musthave 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 aconstant volume of liquid sample to be injected by means of asyringe or liquid sampling valve.5.1.3 Carrier and Detector Gas
19、ControlConstant flowcontrol of carrier and detector gases is critical to optimum 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 rat
20、es. The gas flow rate is measuredby any appropriate means. The supply pressure 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 press
21、ure of 550 kPa (80 psig) issatisfactory.5.1.4 Cryogenic Column CoolingAn initial 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 ca
22、rbon dioxide or liquid nitrogen,controlled through the oven temperature circuitry.5.1.5 DetectorA sulfur 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,
23、(4) no interference orquenching from co-eluting hydrocarbons at the GC samplingvolumes 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
24、 will be those shown in Table1. The column must demonstrate a sufficiently 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
25、 0.32 mm inside diameter fusedsilica wall coated open tube (WCOT) column, 4-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,
26、Head pressure: 70 to 86 kPa(10 to 13 psig).5.2.1.6 DetectorSulfur chemiluminescence detector.5.3 Data Acquisition:5.3.1 RecorderThe use ofa0to1mVrecording 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
27、an electronic integrating de-vice or computer is recommended for determining 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 ti
28、me or relative retention time, orboth, (4) calculation and use of response factors, (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 intend
29、ed thatall reagents conform to the specifications of the Committee onAnalytical 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 lesseni
30、ng the accuracy ofthe determination.6.1.1 Alkane SolventSuch as, iso-octane (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 inges
31、ted or inhaled.)6.1.2 Aromatic SolventSuch as, toluene, Reagent grade,for use 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.(
32、WarningHelium and nitrogen are compressed gases underhigh pressure.) Additional 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
33、.4 Detector GasesHydrogen, nitrogen, air, and oxygenmay be required as detector 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
34、 they support combustion.)6.1.5 External StandardsThe sulfur compounds and ma-trices of external standards should be representative of thesulfur compounds and sample matrices being analyzed. Test3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. F
35、or suggestions 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 (2004)e12Met
36、hods 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 standards.Alternatively, primary standards prepared as described in 6.1.4can be used for method calibration when it is demonstrat
37、ed thatthe matrix does not affect calibration. Only one externalstandard is necessary 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 magnit
38、ude tothose in samples to be analyzed.6.1.6 Internal StandardsDiphenyl sulfide,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 h
39、armfulor fatal when ingested or inhaled.). Any sulfur compound issuitable for use 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
40、orquestionable, analyze the material by any appropriate meansand use the result 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 Stan
41、dards99 + % purity (if avail-able). Obtain pure standard material of all sulfur 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
42、 the result to provideaccurate standard quantities.6.1.8 System Test MixtureGravimetrically 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-
43、propanethiol (;0.1 g/kg), dimethyl disulfide(;10 g/kg), 3-methylthiophene (;100 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,
44、peak asymmetry of a thiol (mercaptan)is an indicator of GC system activity.7. Sampling7.1 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 outline
45、d in Practice D 4057. Asufficient quantity of sample should be taken for multipleanalyses 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 t
46、emperatures above 15C(60F).8. Preparation of Apparatus8.1 ChromatographPlace in service 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 suf
47、ficient equilibration time(for example, 5 to 10 min), adjust the detector output 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 e
48、valuated for compatibility with trace quantities ofreactive sulfur compounds. Inject 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 respon
49、se factors should be calculated for each sulfurcompound in the test mixture (relative 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 6
