1、Designation: D5623 94 (Reapproved 2014)Standard Test Method forSulfur Compounds in Light Petroleum Liquids by GasChromatography and Sulfur Selective Detection1This standard is issued under the fixed designation D5623; the number immediately following the designation indicates the year oforiginal ado
2、ption 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-containing
3、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 v
4、ary 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 components
5、. 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 andmercaptans, are reactive and their
6、 concentration in samplesmay change during sampling and analysis. Coincidently, thetotal sulfur 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 units
7、 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 pract
8、ices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2622 Test Method for Sulfur in Petroleum Products byWavelength Dispersive X-ray Fluorescence SpectrometryD3120 Test Method for Trace Quantities of Sulfur in LightLiquid Petroleum
9、Hydrocarbons by Oxidative Microcou-lometryD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4626 Practice for Calculation of Gas ChromatographicResponse Factors3. Summary of Test Method3.1 The sample is
10、 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 Detection As sulfur compounds elute from thegas chromato
11、graphic 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 sulfur selec
12、tive 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 employed in
13、 down-stream processing. The ability to speciate sulfur compounds in1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Ja
14、n. 15, 2014. Published February 2014. Originallyapproved in 1994. Last previous edition approved in 2009 as D562394(2009).DOI: 10.1520/D5623-94R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandard
15、s volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1various petroleum liquids is useful in controlling sulfur com-pounds in finished products and is fre
16、quently more importantthan knowledge of the total sulfur content alone.5. Apparatus5.1 Chromatograph Use a gas chromatograph (GC) thathas the following performance characteristics:5.1.1 Column Temperature Programmer The chromato-graph must be capable of linear programmed temperatureoperation over a
17、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 musthave variable temperature control c
18、apable 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 Control Constant flowcontrol of carrier
19、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 rates. The gas flow rate is measuredby any
20、 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 pressure of 550 kPa (80 psig) issatisfactory
21、.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 carbon dioxide or liquid nitrogen,control
22、led through the oven temperature circuitry.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-
23、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 will be those shown in Table1. The colu
24、mn 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 0.32 mm inside diameter fusedsilica wal
25、l coated open tube (WCOT) column, 4-m thick filmof methylsilicone.5.2.1.2 Sample size 0.1 to 2.0-L.5.2.1.3 InjectorTemperature 275C; Split ratio: 10:1(10 % to column).5.2.1.4 Column Oven 10C 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 p
26、sig).5.2.1.6 DetectorSulfur chemiluminescence detector.5.3 Data Acquisition:5.3.1 RecorderThe use of a 0 to 1 mV recordingpotentiometer, or equivalent, with a full-scale response time of2 s, or less, is suitable to monitor detector signal.5.3.2 IntegratorThe use of an electronic integrating de-vice
27、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 time or relative retention time, o
28、rboth, (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 intended thatall reagents conform to t
29、he specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be used,3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagent
30、s 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.TABLE 1 Typical Retention Times for Common SulfurCompoundsASul
31、fur Compounds Retention Time (min)Hydrogen Sulfide 0.95Carbonyl Sulfide 1.21Sulfur Dioxide 1.34Methanethiol 3.43Ethanethiol 7.20Dimethyl Sulfide 7.76Carbon Disulfide 8.242-Propanethiol 8.922-methyl-2-propanethiol 10.041-Propanethiol 10.42Ethylmethyl sulfide 10.532-Butanethiol 12.01Thiophene 12.042-m
32、ethyl-1-propanethiol 12.18Diethyl Sulfide 12.821-Butanethiol 13.33Dimethyl Disulfide 13.902-Methylthiophene 14.713-Methylthiophene 14.84Diethyl Disulfide 17.89Methylbenzothiophene 24.55Methylbenzothiophene 24.66Methylbenzothiophene 24.77Methylbenzothiophene 24.88Diphenyl sulfide 28.64AConditions spe
33、cified in 5.2.1.D5623 94 (2014)2provided 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 Solvent Such as, iso-octane (2,2,4-trimethylpentane), Reagent grade, for use as solvent (diluent)in prepar
34、ation 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 Solvent Such as, toluene, Reagent grade,for use as solvent (diluent) in preparation of system testmixtures. (WarningReagent
35、 grade toluene is flammable andis toxic by inhalation, ingestion, and absorption through skin.)6.1.3 Carrier Gas Helium or nitrogen of high purity.(WarningHelium and nitrogen are compressed gases underhigh pressure.) Additional purification is recommended by theuse of molecular sieves or other suita
36、ble 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 detector gases. These gases must be free ofinterfering contaminants, especially s
37、ulfur 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-trices of external standards should be representative of thesulfur compoun
38、ds and sample matrices being analyzed. TestMethods D2622 and D3120 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
39、for method calibration when it is demonstrated 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 sim
40、ilar, for example, within an order of magnitude 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(Wa
41、rningSulfur compounds can be flammable and harmfulor 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
42、 + % when possible). When purity is unknown 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 t
43、o 1 kg of solvent.6.1.7 Sulfur Compound Standards99 + % 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 stand
44、ardmaterial by any appropriate means and use the result to provideaccurate standard quantities.6.1.8 System Test MixtureGravimetrically prepare a stocksolution of sulfur compounds in accordance with PracticeD4307. This solution should cover the volatility range encoun-tered in samples of interest; f
45、or example, dimethyl sulfide(;0.1 g/kg), 2-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-p
46、ropanethiol is notstable in the long term, 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 s
47、hall besampled using the procedures outlined in Practice D4057.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
48、open thesample or standard container at temperatures above 15C(60F).8. Preparation of Apparatus8.1 Chromatograph Place 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 wit
49、h themanufacturers instructions. After sufficient 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 Specification The inlet systemshould be evaluated 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
