1、Designation: D 6733 01 (Reapproved 2006)An American National StandardStandard Test Method forDetermination of Individual Components in Spark IgnitionEngine Fuels by 50-Metre Capillary High Resolution GasChromatography1This standard is issued under the fixed designation D 6733; the number immediately
2、 following the designation 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.1. Scope1.1 This test
3、method covers the determination of individualhydrocarbon components of spark-ignition engine fuels withboiling ranges up to 225C. Other light liquid hydrocarbonmixtures typically encountered in petroleum refining opera-tions, such as, blending stocks (naphthas, reformates, alkylates,and so forth) ma
4、y also be analyzed; however, statistical datawas obtained only with blended spark-ignition engine fuels.The tables in Annex A1 enumerate the components reported.Component concentrations are determined in the range from0.10 to 15 mass %. The procedure may be applicable to higherand lower concentratio
5、ns for the individual components; how-ever, the user must verify the accuracy if the procedures areused for components with concentrations outside the specifiedranges.1.2 This test method is applicable also to spark-ignitionengine fuel blends containing oxygenated components. How-ever, in this case,
6、 the oxygenate content must be determined byTest Methods D 5599 or D 4815.1.3 Benzene co-elutes with 1-methylcyclopentene. Benzenecontent must be determined by Test Method D 3606 or D 5580.1.4 Toluene co-elutes with 2,3,3-trimethylpentane. Toluenecontent must be determined by Test Method D 3606 or D
7、 5580.1.5 Although a majority of the individual hydrocarbonspresent are determined, some co-elution of compounds isencountered. If this procedure is utilized to estimate bulkhydrocarbon group-type composition (PONA) the user of suchdata should be cautioned that error may be encountered due toco-elut
8、ion and a lack of identification of all componentspresent. Samples containing significant amounts of naphthenic(for example, virgin naphthas) constituents above n-octanemay reflect significant errors in PONA type groupings. Basedon the interlaboratory cooperative study, this procedure isapplicable t
9、o samples having concentrations of olefins less than20 mass %. However, significant interfering coelution with theolefins above C7is possible, particularly if blending compo-nents or their higher boiling cuts such as those derived fromfluid catalytic cracking (FCC) are analyzed, and the total olefin
10、content may not be accurate. Many of the olefins in sparkignition fuels are at a concentration below 0.10 %; they are notreported by this test method and may bias the total olefinresults low.1.5.1 Total olefins in the samples may be obtained orconfirmed, or both, by Test Method D 1319 (volume %) oro
11、ther test methods, such as those based on multidimensionalPONA type of instruments.1.6 If water is or is suspected of being present, its concen-tration may be determined, if desired, by the use of TestMethod D 1744. Other compounds containing sulfur, nitrogen,and so forth, may also be present, and m
12、ay co-elute with thehydrocarbons. If determination of these specific compounds isrequired, it is recommended that test methods for these specificmaterials be used, such as Test Method D 5623 for sulfurcompounds.1.7 The values stated in SI units are to be regarded as thestandard. The values given in
13、parentheses are provided forinformation only.1.8 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 practices and determine the applica-bility of regula
14、tory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1319 Test Method for Hydrocarbon Types in LiquidPetroleum Products by Fluorescent Indicator AdsorptionD 1744 Standard Test Method for Determination of Waterin Liquid Petroleum Products by Karl Fischer Reagent3D 3606 Test Meth
15、od for Determination of Benzene andToluene in Finished Motor and Aviation Gasoline by GasChromatography1This 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
16、 edition approved Nov. 1, 2006. Published January 2007. Originallyapproved in 2001. Last previous edition approved in 2001 as D 6733 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
17、formation, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4420 Test Method for Determ
18、ination of Aromatics inFinished Gasoline by Gas Chromatography3D 4815 Test Method for Determination of MTBE, ETBE,TAME, DIPE, tertiary-Amyl Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD 5580 Test Method for Determination of Benzene, Tolu-ene, Ethylbenzene, p/m-Xylene, o-Xylene, C9a
19、nd HeavierAromatics, and Total Aromatics in Finished Gasoline byGas ChromatographyD 5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionD 5623 Test Method for Sulfur Compounds in Light Petro-leum Liquids by Gas Chromatograph
20、y and Sulfur Selec-tive DetectionE 355 Practice for Gas Chromatography Terms and Rela-tionships3. Terminology3.1 DefinitionsThis test method makes reference to manycommon gas chromatographic procedures, terms, and relation-ships. Detailed definitions can be found in Practice E 355.4. Summary of Test
21、 Method4.1 Representative samples of the petroleum liquid areintroduced into a gas chromatograph equipped with an opentubular (capillary) column coated with specified stationaryphase(s). Helium carrier gas transports the vaporized samplethrough the column in which it is partitioned into individualco
22、mponents, which are sensed with a flame ionization detectoras they elute from the end of the column. The detector signalis recorded digitally by way of an integrator or integratingcomputer. Each eluting component is identified by comparingits retention time to those established by analyzing referenc
23、estandards or samples under identical conditions. The concen-tration of each component in mass % is determined by normal-ization of the peak areas after correction of selected compo-nents with detector response factors. The unknowncomponents are reported individually as well as a summarytotal.5. Sig
24、nificance and Use5.1 Knowledge of the individual component composition(speciation) of gasoline fuels and blending stocks is useful forrefinery quality control and product specification. Processcontrol and product specification compliance for many indi-vidual hydrocarbons may be determined through th
25、e use of thistest method.6. Apparatus6.1 InstrumentationA gas chromatograph capable of op-erating under the conditions outlined in Table 1, equipped witha split injector, a carrier gas pressure control, and a flameionization detector which are required.6.2 Sample Introduction SystemManual or automat
26、ic liq-uid syringe sample injection may be employed.6.3 Data Acquisition SystemAny data system can be usedwith a requirement:6.3.1 Sampling rate of 10 Hz or more with a storage ofsampling data for later processing.6.3.2 Capacity for at least 400 peaks/analysis.6.3.3 Identification of individual comp
27、onents from retentiontime; software can be used to automatically identify the peakswith the index system determined from Table A1.1 or TableA1.2.6.4 SamplingTwo millilitres or more crimp-top vials andaluminum caps with polytetrafluoroethylene (PTFE)-linedsepta are used to transfer the sample.6.5 Cap
28、illary ColumnA 50 m fused silica capillary col-umn with an internal diameter of 0.2 mm, containing a 0.5 mfilm thickness of bonded dimethylpolysiloxane phase is used.The features must be respected to reproduce the separation ofthe reference chromatogram. The column must meet thecriteria of efficienc
29、y, resolution, and polarity defined in Section10.7. Reagents and Materials7.1 Carrier Gas and Make-up, helium, 99.99 mol % pure.(WarningCompressed gas under high pressure.)7.2 Fuel Gas, hydrogen, hydrocarbon free, 99.99 mol %pure. (WarningCompressed gas under high pressure. Ex-tremely flammable.)7.3
30、 Oxidizing Gas, air, 99 mol %. (WarningCompressedgas under high pressure.)7.4 n-Pentane, 99+ mol % pure. (WarningExtremelyflammable. Harmful if inhaled.)7.5 n-Hexane, 99+ % mol % pure. (WarningExtremelyflammable. Harmful if inhaled.)7.6 n-Heptane, 99+ mol % pure. (WarningExtremelyflammable. Harmful
31、if inhaled.)7.7 2-Methylheptane, 99+ mol % pure. (WarningExtremely flammable. Harmful if inhaled.)7.8 4-Methylheptane, 99+ mol % pure. (WarningExtremely flammable. Harmful if inhaled.)7.9 n-Octane, 99+ mol % pure. (WarningExtremelyflammable. Harmful if inhaled.)7.10 n-Dodecane, 99+ mol % pure. (Warn
32、ingExtremelyflammable. Harmful if inhaled.)TABLE 1 Operating ConditionsTemperatures Method 1 Method 2Column initial isotherm, C 35 10Initial hold time, min. 10 15Rate 1, C/min. 1.1 1.3Final temperature 1, C 114 70Hold time 2, min. 0 0Rate 2, C/min 1.7 1.7Final temperature 2, C 250 250Final hold time
33、 2, min. 5 20Injector, C 250 250Detector, C 280 280Carrier gas helium pressure, kPA (psi) 207 (30) 190 (27)Flow rate (initial isotherm), mL/min. 0.9 0.7Average linear velocity, cm/s 22 21.5InjectionSample size, L 0.5 0.3Splitter ventflow out, mL/min. 250 200D 6733 01 (2006)27.11 Toluene, 99+ mol % p
34、ure. (WarningExtremelyflammable. Harmful if inhaled.)7.12 System Performance MixtureWeigh an equal amountof n-pentane, n-heptane, n-octane, n-dodecane,2-methylheptane, 4-methylheptane, and toluene. Dilute thismixture in n-hexane to obtain a concentration of 2 mass % foreach compound.8. Sampling8.1 C
35、ontainer SamplingSamples shall be taken as de-scribed in Practice D 4057 for instructions on manual samplinginto open container.8.2 The sample and a 2mL vial must be cooled at 4C. Partof the sample is transferred to the vial up to 80 % of its volume,and aluminum cap with septum is crimped.9. Prepara
36、tion of Apparatus9.1 InstallationInstall and condition column in accor-dance with the suppliers instruction.9.2 Operating ConditionsTwo sets of operating condi-tions are proposed in Table 1, the first with an initial columntemperature above the ambient temperature, the second with asub-ambient colum
37、n temperature profile. Adjust the operatingconditions of the gas chromatograph to conform to the first orsecond method.9.3 Carrier Gas PressureSet a correct carrier gas pressureusing the system performance mixture such that the retentiontime of n-Heptane, n-Octane and n-Dodecane are between thevalue
38、s given in Table 2.10. System Performance Evaluation10.1 Evaluation of the column and linearity of the splitinjection are carried out with a system performance mixturedefined in 7.12 and with the column temperature conditionsdefined in the following table.Initial temperature 35CHold time 50 min.Fina
39、l temperature 220CHold time 20 min.Rate 3C/min.10.2 Column EvaluationTo perform the required separa-tion, the column must meet three criteria of separation:efficiency, resolution, and polarity.10.2.1 EffciencyThe number of theoretical plates is cal-culated with the normal octane peak using Eq 1:n 5
40、5.545Rt/W0.5!2(1)where:n = number of theoretical plates,Rt = retention time of normal octane, andW0.5= mid-height peak width of normal octane in thesame unit as retention time.10.2.1.1 The number of theoretical plates must be greaterthan 200 000.10.2.2 ResolutionResolution is determined between thep
41、eaks of 2-methylheptane and 4-methylheptane using Eq 2:R 52Rta! Rtb!1.699W0.5a!1 W0.5b!(2)where:Rt(a)= retention time of 4-methylheptane,Rt(b)= retention time of 2-methylheptane,W0.5(a)= mid-height peak width of 4-methylheptane inthe same unit as retention time, andW0.5(b)= mid-height peak width of
42、2-methylheptane inthe same unit as retention time.10.2.2.1 The resolution must be equal to 4or greater than1.20.10.2.3 PolarityPolarity is defined by the McReynoldsconstant of toluene, using Eq 3:Rntol5 Kiana Kisqualane(3)where:Kisqualane= toluene Kovats index on Squalane at35C = 742.6, andKiana= to
43、luene Kovats index on the analytical col-umn at 35C.10.2.3.1 Toluene Kovats index is calculated using Eq 4:Kiana5 700 1 100Slog T8Rt! log T8Rh!log T8Ro! log T8Rh!D(4)where:T8R(t)= adjusted retention time for toluene,T8R(h)= adjusted retention time for n-heptane, andT8R(o)= adjusted retention time fo
44、r n-octane.10.2.3.2 Adjusted retention time of a peak is determined bysubtracting the retention time of an unretained compound (airor methane) from the retention time of the peak. The McRey-nolds constant must be less than 10.10.2.4 Base Line StabilityBase line stability is calculatedwith the differ
45、ence between area slices at the beginning and atthe end of analysis, divided by the maximum area slice ofN-octane obtained with the system performance mixture.10.2.4.1 Measurement of the StabilityCarry out one tem-perature programming defined in 10.1 without injecting anysample. Subtract the area sl
46、ices at the start of the analysis withthose corresponding to 120 min (average of three slices).10.2.4.2 Stability StandardizationStandardization is car-ried out using the system performance mixture defined in 7.12with the column temperature conditions defined in 10.1. Thevalue obtained in 10.2.4.1 i
47、s divided by the maximum areaslice of N-octane and multiplied by 100. The value obtainedmust be less than 2 %. If this is not the case, check for possibleleaks, or recondition the column according to the manufactur-ers recommendations.TABLE 2 Reference Retention Times of Normal ParaffinsNOTEMinutes
48、and tenths of a minute.Method 1 Method 1 Method 1 Method 2 Method 2 Method 2n-Paraffins LowerTimeReferenceTimeUpperTimeLowerTimeReferenceTimeUpperTimen-Heptane 18.5 19.4 20.3 39.5 40.7 42.0n-Octane 32.0 33.0 34.0 57.0 57.8 59.0n-Dodecane 92.8 94.0 95.2 106.4 107.6 108.8D 6733 01 (2006)310.3 Evaluati
49、on of the Linearity of the Split InjectorEvaluation is carried out using the system performance mixturedefined in 7.12 with the column temperature conditions definedin 10.1. The % (m/m) of each compound is determined fromthe corrected area % using the response factors for eachcompound given in Table A1.1 or Table A1.2. The relativepercent error is determined from the known mixture concen-trations according to Eq 5:Relative % error 5100 calculated concentration known concentration!known concentration(5)10.3.1 Th
