1、Designation: D6591 11 (Reapproved 2017)Designation: 548/06Standard Test Method forDetermination of Aromatic Hydrocarbon Types in MiddleDistillatesHigh Performance Liquid ChromatographyMethod with Refractive Index Detection1This standard is issued under the fixed designation D6591; the number immedia
2、tely 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 () indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis te
3、st method has the same title as IP 548-06 and is intended to be technically equivalent. TheASTM format for test methods has been used, and where possible, equivalent ASTM test methodshave replaced the IP or ISO standards.The test method is intended to be used as one of several possible alternative i
4、nstrumental testmethods that are aimed at quantitative determination of hydrocarbon types in fuels. This does notimply that a correlation necessarily exists between this and any other test method intended to give thisinformation, and it is the responsibility of the user to determine such correlation
5、 if necessary.1. Scope1.1 This test method covers a high performance liquidchromatographic test method for the determination of mono-aromatic, di-aromatic, tri+-aromatic, and polycyclic aromatichydrocarbon contents in diesel fuels and petroleum distillatesboiling in the range from 150 C to 400 C. Th
6、e total aromaticcontent in % m/m is calculated from the sum of the corre-sponding individual aromatic hydrocarbon types.NOTE 1Aviation fuels and petroleum distillates with a boiling pointrange from 50 C to 300 C are not determined by this test method andshould be analyzed by Test Method, D6379 or ot
7、her suitable equivalenttest methods.1.2 The precision of this test method has been establishedfor diesel fuels and their blending components, containingfrom 4 % to 40 % (m/m) mono-aromatic hydrocarbons, 0 % to20 % (m/m) di-aromatic hydrocarbons, 0 % to 6 % (m/m)tri+-aromatic hydrocarbons, 0 % to 26
8、% (m/m) polycyclicaromatic hydrocarbons, and 4 % to 65 % (mm) total aromatichydrocarbons.1.3 Compounds containing sulfur, nitrogen, and oxygen arepossible interferents. Mono-alkenes do not interfere, but con-jugated di- and poly-alkenes, if present, are possible interfer-ents.1.4 By convention, this
9、 standard defines the aromatic hy-drocarbon types on the basis of their elution characteristicsfrom the specified liquid chromatography column relative tomodel aromatic compounds. Quantification is by externalcalibration using a single aromatic compound, which may ormay not be representative of the
10、aromatics in the sample, foreach aromatic hydrocarbon type. Alternative techniques andmethods may classify and quantify individual aromatic hydro-carbon types differently.1.5 Fatty Acid Methyl Esters (FAME), if present, interferewith tri+-aromatic hydrocarbons. If this method is used fordiesel conta
11、ining FAME, the amount of tri+-aromatics will beover estimated.1.6 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 applic
12、a-bility of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by t
13、he World Trade Organization TechnicalBarriers to Trade (TBT) Committee.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0C on Liquid Chromatography.This test method is based on
14、material published in IP Standard Methods forAnalysis and Testing of Petroleum and Related Products and British Standard 2000Parts, copyright The Institute of Petroleum, 61 New Cavendish Street, LondonW1M 8AR. Adapted with permission of The Institute of Petroleum.Current edition approved May 1, 2017
15、. Published July 2017. Originally approvedin 2000. Last previous edition approved in 2011 as D6591 11. DOI: 10.1520/D6591-11R17.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance wit
16、h internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.12. Referenced Documents2.1 ASTM Standards
17、:2D1319 Test Method for Hydrocarbon Types in Liquid Petro-leum Products by Fluorescent Indicator AdsorptionD2425 Test Method for Hydrocarbon Types in Middle Dis-tillates by Mass SpectrometryD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of
18、Petroleum andPetroleum ProductsD5186 Test Method for Determination of the AromaticContent and Polynuclear Aromatic Content of DieselFuels and Aviation Turbine Fuels By Supercritical FluidChromatographyD6379 Test Method for Determination of Aromatic Hydro-carbon Types in Aviation Fuels and PetroleumD
19、istillatesHigh Performance Liquid ChromatographyMethod with Refractive Index Detection2.2 Energy Institute Standard:3IP 548 Test Method for Determination of Aromatic Hydro-carbon Types in Middle Distillates High PerformanceLiquid Chromatography Method with Refractive IndexDetection3. Terminology3.1
20、Definitions of Terms Specific to This Standard:3.1.1 di-aromatic hydrocarbons (DAHs), nin this testmethod, compounds that have a longer retention time on thespecified polar column than the majority of mono-aromatichydrocarbons, but a shorter retention time than the majority oftri+-aromatic hydrocarb
21、ons.3.1.2 mono-aromatic hydrocarbons (MAHs), nin this testmethod, compounds that have a longer retention time on thespecified polar column than the majority of non-aromatichydrocarbons but a shorter retention time than the majority ofDAHs.3.1.3 non-aromatic hydrocarbons, nin this test method,compoun
22、ds that have a shorter retention time on the specifiedpolar column than the majority of mono-aromatic hydrocar-bons.3.1.4 polycyclic aromatic hydrocarbons (POLY-AHs), ninthis test method, sum of the di-aromatic hydrocarbons andtri+-aromatic hydrocarbons.3.1.5 total aromatic hydrocarbons, nin this te
23、st method,sum of the MAHs, DAHs, and T+AHs.3.1.6 tri+-aromatic hydrobons (T+AHs), nin this testmethod, compounds that have a longer retention time on thespecified polar column than the majority of DAHs.3.1.6.1 DiscussionThe elution characteristics of aromaticand non-aromatic compounds on the specifi
24、ed polar columnhave not been specifically determined for this test method.Published and unpublished data indicate the major constituentsfor each hydrocarbon type as follows: (1) non-aromatic hydro-carbons: acyclic and cyclic alkanes (paraffins and naphthenes),mono-alkenes (if present), (2) MAHs: ben
25、zenes, tetralins,indanes, thiophenes, and conjugated poly-alkenes, (3) DAHs:naphthalenes, biphenyls, indenes, fluorenes, acenaphthenes,and benzothiophenes and dibenzothiophenes, (4) T+AHs:phenanthrenes, pyrenes, fluoranthenes, chrysenes,triphenylenes, and benzanthracenes.4. Summary of Test Method4.1
26、 A known mass of sample is diluted in the mobile phase,and a fixed volume of this solution is injected into a highperformance liquid chromatograph, fitted with a polar column.This column has little affinity for the non-aromatic hydrocar-bons while exhibiting a pronounced selectivity for aromatichydr
27、ocarbons. As a result of this selectivity, the aromatichydrocarbons are separated from the non-aromatic hydrocar-bons into distinct bands in accordance with their ring structure,that is, MAHs, DAHs, and T+AHs. At a predetermined time,after the elution of the DAHs, the column is backflushed toelute t
28、he T+AHs as a single sharp band.4.2 The column is connected to a refractive index detectorthat detects the components as they elute from the column. Theelectronic signal from the detector is continually monitored bya data processor. The amplitudes of the signals (peak areas)from the sample aromatics
29、 are compared with those obtainedfrom previously measured calibration standards in order tocalculate percent m/m MAHs, DAHs, and T+AHs in thesample. The sum of the percentages by mass of DAHs andT+AHs is reported as the percent m/m POLY-AH. The sum ofMAHs, DAHs, and T+AHs is reported as the total ar
30、omaticcontent (percent m/m) of the sample.5. Significance and Use5.1 The aromatic hydrocarbon content of motor diesel fuelis a factor that can affect exhaust emissions and fuel combus-tion characteristics, as measured by cetane number.5.2 The United States Environmental Protection Agency(US EPA) reg
31、ulates the aromatic content of diesel fuels.California Air Resources Board (CARB) regulations placelimits on the total aromatics content and polynuclear aromatichydrocarbon content of motor diesel fuel, thus requiring anappropriate analytical determination to ensure compliance withthe regulations.5.
32、3 This test method is applicable to materials in the sameboiling range as motor diesel fuels and is unaffected by fuelcoloration. Test Method D1319, which has been mandated bythe US EPA for the determination of aromatics in motor dieselfuel, excludes materials with final boiling points greater than3
33、15 C (600 F) from its scope. Test Method D2425 is appli-cable to the determination of both total aromatics and poly-nuclear aromatic hydrocarbons in diesel fuel, but is much morecostly and time-consuming to perform. Test Method D5186,currently specified by CARB, is also applicable to the deter-minat
34、ion of both total aromatics and polynuclear aromatichydrocarbons in diesel fuel. Test Method D5186, however,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 stan
35、dards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.D6591 11 (2017)2specifies the use of supercritical fluid chromatography equip-ment that may not be readily available.NOTE 2Test Method D5186 was previ
36、ously specified by CARB as analternative to Test Method D1319.6. Apparatus6.1 High Performance Liquid Chromatograph (HPLC)Any HPLC capable of pumping the mobile phase at flow ratesbetween 0.5 mLmin and 1.5 mLmin, with a precision betterthan 0.5 % and a pulsation of 99 % pure.NOTE 7Cyclohexane may co
37、ntain benzene as an impurity.7.2 Heptane, HPLC Grade. For use as HPLC mobile phase.(WarningHeptane is highly flammable and may causeirritation by inhalation, ingestion, or skin contact.)NOTE 8Batch to batch variation of the solvent quality in terms ofwater content, viscosity, refractive index and pu
38、rity could cause unpre-dictable column behavior. Drying and filtering the mobile phase couldhelp to reduce the effect of the trace impurities in the solvent.NOTE 9It is recommended practice to degas the HPLC mobile phasebefore use; this can be done conveniently, on-line, or off-line by heliumspargin
39、g, vacuum degassing or ultrasonic agitation.Afailure to de-gas themobile phase may lead to negative peaks.7.3 o-Xylene (1,2-Dimethylbenzene), 98 % pure.7.4 1-Methylnaphthalene, 98 % pure.7.5 Phenanthrene, 98 % pure.7.6 Dibenzothiophene, 95 % pure.7.7 9-Methylanthracene, 95 % pure. (WarningGlovesshou
40、ld be worn when handling aromatic compounds (forexample, disposable vinyl gloves).)NOTE 10Purity is determined by gas chromatography with flameionization detection. The highest purity standards available should beused.8. Sampling8.1 Unless otherwise specified in the commodityspecification, samples a
41、re taken by following Practice D4057or D4177, or a similar standard. In certain situations, samplingis done in accordance with the requirements of nationalstandards or regulations for the sampling of the product undertest.D6591 11 (2017)39. Apparatus Preparation9.1 Set up the chromatograph, injectio
42、n system, column,backflush valve, column oven, refractive index detector, andcomputing integrator in accordance with the appropriate equip-ment manuals. Install the HPLC column and backflush valve inthe column oven. Insert the backflush valve so that the detectoris always connected independently of
43、the direction of flowthrough the column (see Fig. 1). Maintain the sample injectionvalve at the same temperature as the sample solution; in mostcases this will be at room temperature.NOTE 11The column oven is optional if alternative arrangements aremade to maintain a constant temperature environment
44、, for example, atemperature-controlled laboratory (see 6.5). It is recommended to installthe backflush valve in the column oven and to install the apparatus awayfrom drafts (that is, not near air-conditioning unit or fume cupboard).Pipework and/or valving which is not temperature controlled should b
45、einsulated.NOTE 12Regular maintenance of the liquid chromatograph and itscomponents is important to ensure consistent performance. Leakages andpartial blockage of filters, frits, injector needles and valve rotors canproduce flow rate inconsistencies and poor injector performance.9.2 Adjust the flow
46、rate of the mobile phase to a constant1.0 mLmin 6 0.2 mLmin, and ensure the reference cell ofthe refractive index detector is full of mobile phase. Allow thetemperature of the column oven (and refractive index detector,if equipped with temperature control) to stabilize.9.2.1 To minimize drift, it is
47、 essential to make sure thereference cell is full of solvent.The best way to accomplish thisis either (1) to flush the mobile phase through the reference cell(then isolate the reference cell to prevent evaporation of thesolvent) immediately prior to analysis, or (2) to continuouslymake up for solven
48、t evaporation by supplying a steady flowthrough the reference cell. The make-up flow is optimized sothat reference and analytical cell miss-match due to drying-out,temperature, or pressure gradients are minimized. Typically,this can be accomplished with a make-up flow set at one tenthof the analytic
49、al flow.NOTE 13The flow rate may be adjusted (typically within the rangefrom 0.8 mL min to 1.2 mL min) to an optimum value in order to meetthe resolution requirements specified in 9.4.3.9.3 Prepare a system performance standard (SPS) by weigh-ing cyclohexane (1.0 g 6 0.1 g), o-xylene (0.5 g 6 0.05 g),dibenzothiophene (0.05 g 6 0.005 g) and 9-methylanthracene(0.05 g 6 0.005 g) into a 100 mL volumetric flask and makingup to the mark with heptane. Ensure that the dibenzothiopheneand 9-methylanthracene are dissolved in the o-xylene-cyclohe
