1、Designation: D6730 01 (Reapproved 2016)Standard Test Method forDetermination of Individual Components in Spark IgnitionEngine Fuels by 100Metre Capillary (with Precolumn) High-Resolution Gas Chromatography1This standard is issued under the fixed designation D6730; the number immediately following th
2、e 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers
3、the determination of individualhydrocarbon components of spark-ignition engine fuels andtheir mixtures containing oxygenate blends (MTBE, ETBE,ethanol, and so forth) with boiling ranges up to 225 C. Otherlight liquid hydrocarbon mixtures typically encountered inpetroleum refining operations, such as
4、 blending stocks(naphthas, reformates, alkylates, and so forth) may also beanalyzed; however, statistical data was obtained only withblended spark-ignition engine fuels.1.2 Based on the cooperative study results, individual com-ponent concentrations and precision are determined in therange from 0.01
5、 % to approximately 30 % by mass. The testmethod may be applicable to higher and lower concentrationsfor the individual components; however, the user must verifythe accuracy if the test method is used for components withconcentrations outside the specified ranges.1.3 This test method also determines
6、 methanol, ethanol,t-butanol, methyl t-butyl ether (MTBE), ethyl t-butyl ether(ETBE), and t-amyl methyl ether (TAME) in spark ignitionengine fuels in the concentration range from 1 % to 30 % bymass. However, the cooperative study data provided insuffi-cient statistical data for obtaining a precision
7、 statement forthese compounds.1.4 Although a majority of the individual hydrocarbonspresent are determined, some co-elution of compounds isencountered. If this test method is utilized to estimate bulkhydrocarbon group-type composition (PONA), the user of suchdata should be cautioned that some error
8、will be encountereddue to co-elution 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 gasoline samples in the interla
9、boratory cooperativestudy, this test method is applicable to samples containing lessthan 25 % by mass of olefins. However, some interferingco-elution with the olefins above C7is possible, particularly ifblending components or their higher boiling cuts such as thosederived from fluid catalytic cracki
10、ng (FCC) are analyzed, andthe total olefin content may not be accurate. Annex A1 of thistest method compares results of the test method with other testmethods for selected components, including olefins, and sev-eral group types for several interlaboratory cooperative studysamples. Although benzene,
11、toulene, and several oxygenatesare determined, when doubtful as to the analytical results ofthese components, confirmatory analyses can be obtained byusing the specific test methods listed in the reference section.1.4.1 Total olefins in the samples may be obtained orconfirmed, or both, if necessary,
12、 by Test Method D1319(percent by volume) or other test methods, such as those basedon multidimentional PONA-type of instruments.1.5 If water is or is suspected of being present, its concen-tration may be determined, if desired, by the use of TestMethod D1744 or equivalent. Other compounds containing
13、oxygen, sulfur, nitrogen, and so forth, may also be present, andmay co-elute with the hydrocarbons. If determination of thesespecific compounds is required, it is recommended that testmethods for these specific materials be used, such as TestMethods D4815 and D5599 for oxygenates, and Test MethodD56
14、23 for sulfur compounds, or equivalent.1.6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the
15、user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofS
16、ubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved April 1, 2016. Published May 2016. Originallyapproved in 2001. Last previous edition approved in 2011 as D6730 01 (2011).DOI: 10.1520/D6730-01R16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
17、hocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:2D1319 Test Method for Hydrocarbon Types in Liquid Petro-leum Products by Fluorescent Indicator AdsorptionD1744 Test Method for Determination of Water in LiquidPetroleum Products by Karl Fischer Reagent (Withdrawn2016)3D3
18、700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4626 Pra
19、ctice for Calculation of Gas ChromatographicResponse FactorsD4815 Test Method for Determination of MTBE, ETBE,TAME, DIPE, tertiary-Amyl Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD5580 Test Method for Determination of Benzene, Toluene,Ethylbenzene, p/m-Xylene, o-Xylene, C9and Heav
20、ierAromatics, and Total Aromatics in Finished Gasoline byGas ChromatographyD5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionD5623 Test Method for Sulfur Compounds in Light Petro-leum Liquids by Gas Chromatography and Sul
21、fur Selec-tive DetectionE355 Practice for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs3. Terminology3.1 De
22、finitionsThis test method makes reference to manycommon gas chromatographic procedures, terms, and relation-ships. Detailed definitions can be found in Practice E355.4. Summary of Test Method4.1 A representative sample of the petroleum liquid isintroduced into a gas chromatograph equipped with an op
23、entubular (capillary) column coated with a methyl silicone liquidphase, modified with a capillary precolumn. Helium carrier gastransports the vaporized sample through the column, in whichit is partitioned into individual components which are sensedwith a flame ionization detector as they elute from
24、the end ofthe column. The detector signal is presented on a strip chartrecorder or digitally, or both, by way of an integrator orintegrating computer. Each eluting component is identified bycomparing its retention time to that established by analyzingreference standards or samples under identical co
25、nditions. Theconcentration of each component in percent by mass isdetermined by normalization of the peak areas after correctionwith detector response factors. Unknown components arereported as a total unknown percent by mass.5. Significance and Use5.1 Knowledge of the individual component compositi
26、on(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 can be determined through the use of thistest method.5.2 This test method is adopted from earlie
27、r developmentand enhancement.4,5,6,7The chromatographic operating condi-tions and column tuning process, included in this test method,were developed to provide and enhance the separation andsubsequent determination of many individual components notobtained with previous single-column analyses. The c
28、olumntemperature program profile is selected to afford the maximumresolution of possible co-eluting components, especially wherethese are of two different compound types (for example, aparaffin and a naphthene).5.3 Although a majority of the individual hydrocarbonspresent in petroleum distillates ar
29、e determined, some co-elution of compounds is encountered. If this test method isutilized to determine bulk hydrocarbon group-type composi-tion (PONA), the user of such data should be cautioned thatsome error will be encountered due to co-elution and a lack ofidentification of all components present
30、. Samples containingsignificant amounts of olefinic or naphthenic, or both, constitu-ents above octane may reflect significant errors in PONA-typegroupings.5.4 If water is or is suspected of being present, its concen-tration is determined by the use of Test Method D1744. Othercompounds containing ox
31、ygen, sulfur, nitrogen, and so forthmay also be present, and may co-elute with the hydrocarbons.When known co-elution exists, these are noted in the testmethod data tables. If determination of these specific com-pounds is required, it is recommended that test methods forthese specific materials be u
32、sed, such as Test Method D4815and D5599 for oxygenates, Test Method D5580 for aromatics,and Test Method D5623 for sulfur compounds.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
33、tion, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Johansen, N.G., and Ettre, L.S., “Retention Index Values of Hydrocarbons onOpen Tubular Columns Coated with Methyl Silicone Liquid Phases,”Chroma
34、tographia, Vol 5, No. 10, October 1982.5Johansen, N.G., Ettre, L.S., and Miller, R.L., “Quantitative Analysis ofHydrocarbons by Structural Group Type in Gasolines and Distillates. Part 1,”Journal of Chromatography, Vol 256, 1983, pp. 393417.6Kopp, V.R., Bones, C.J., Doerr, D.G., Ho, S.P., and Schube
35、rt, A.J., “HeavyHydrocarbon/Volatility Study: Fuel Blending and Analysis for the Auto/Oil AirQuality Improvement Research Program,” SAE Paper No. 930143, March 1993.7Schubert, A.J. and Johansen, N.J., “Cooperative Study to Evaluate a StandardTest Method for the Speciation of Gasolines by Capillary G
36、as Chromatography,”SAE Paper No. 930144, March 1993.D6730 01 (2016)26. Apparatus6.1 Gas ChromatographInstrumentation capable of col-umn oven temperature programming, from subambient (5 C)to at least 200 C, in 0.1 Cmin or less rate increments, isrequired. Multi-step column oven temperature programmin
37、g isrequired, consisting of an initial hold time, an initial tempera-ture program followed by an isothermal temperature hold andanother programmed temperature rise. A heated flash vaporiz-ing injector designed to provide a linear sample split injection(that is, 200:1) is required for proper sample i
38、ntroduction. Theassociated carrier gas controls must be of sufficient precision toprovide reproducible column flows and split ratios in order tomaintain analytical integrity. A hydrogen flame ionizationdetector, with associated gas controls and electronics, designedfor optimum response with open tub
39、ular columns, shall con-form to the specifications as described in Practice E594, as wellas having an operating temperature range of up to at least250 C.6.2 Sample IntroductionManual or automatic liquidsample injection to the splitting injector may be employed.Automated injections are highly recomme
40、nded. Micro-syringes, auto-syringe samplers, or valves capable of 0.1 L to0.5 L. injections are suitable. It should be noted that somesyringes and improper injection techniques as well as inad-equate splitter design could result in sample fractionation. Thismust be determined in accordance with Sect
41、ion 10.6.3 Electronic IntegratorAny electronic integration de-vice used for quantitating these analyses shall meet or exceedthese minimum requirements:6.3.1 Capacity to handle 400 or more peaks per analysis.6.3.2 Normalized area percent calculation with responsefactors.6.3.3 Noise and spike rejectio
42、n.6.3.4 Accurate area determination of fast (1 s to 2 s) peaks(10 Hz or greater sampling rate).6.3.5 Maintain peak detection sensitivity for narrow andbroad peaks.6.3.6 Positive and negative sloping baseline correction.6.3.7 Perpendicular drop and tangent skimming as needed.6.3.8 Display of baseline
43、 used to ensure correct peak areadetermination.6.4 Open Tubular ColumnThe column used for this testmethod consists of a primary (100 m) analytical column and aprecolumn. The ability to provide the required componentseparations is dependent on the precise control of the columnselectivity, which is ty
44、pically slightly more than that exhibitedby current commercially available columns. Some oldercolumns, and columns that have a sample residue fromrepeated use without conditioning, may exhibit the requiredpolarity. Until adequate columns are commercially available,the currently used methyl silicone
45、columns can be modified ortuned to meet the method column specifications. See Section11 for a description of the column performance specificationsand Annex A1 for a description of the column modificationprocedure.6.4.1 The primary gas chromatographic column used forthis test method will meet the fol
46、lowing specifications.Material fused silicaLength 100 mInternal diameter 0.25 mmLiquid phase methyl siliconeFilm thickness 0.50 mTheoretical plates, n, pentane at 35 C ; 400 000 to 500 000Retention factor, k, pentane at 35 C 0.45 to 0.50Resolution, R, t-butanol and 2-methylbutene-2 at35 C3.25 to 5.2
47、5Peak symmetry, t-butanol at 35 C 1.0 to sample: 0.2 L, 0.5 L, 1.0 Linjector temperature: 300 C sample: 0.2 L, 0.5 L, 1.0 L10.3 Compare the calculated concentrations to the knownstandard concentrations after calculating the corrected areanormalization using the response factors from 13.2 and TableA1
48、.1.% relative error5 (2)100 3 concentration determined2concentration known)/concentration known10.4 Report and use only those combinations of conditionsfrom 10.2 that result in 3 % or less relative error. This is thesplitter linearity range.11. Column Evaluation11.1 In order to establish that a colu
49、mn will perform asrequired, the following specifications shall be determined fornew column acceptability and are useful for periodic evalua-tion of column deterioration. These specification determina-tions can be made with or without a precolumn, since theprecolumn will have little effect on their values. See AnnexA1,Fig.A1.1, for examples of these determinations.After perform-ing the steps in Sections 9 and 10, analyze the columnperformance mixture (7.5.5) at 35 C isothermal, at leastthrough heptane. The remainder of the analysis may beignored, but the
