ASTM D6591-2006 Standard Test Method for Determination of Aromatic Hydrocarbon Types in Middle Distillates-High Performance Liquid Chromatography Method with Refractive Index Detec.pdf

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1、Designation: D 6591 06Designation: 548/06An American National StandardStandard Test Method forDetermination of Aromatic Hydrocarbon Types in MiddleDistillatesHigh Performance Liquid ChromatographyMethod with Refractive Index Detection1This standard is issued under the fixed designation D 6591; the n

2、umber immediately 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.INTRO

3、DUCTIONThis test 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

4、 alternative instrumental 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 su

5、ch correlation if necessary.1. Scope*1.1 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

6、 to 400C. The 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 to 300C are not determined by this test method and shouldbe analyzed by Test Method, D

7、6379 or other suitable equivalent testmethods.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 to 20 %(m/m) di-aromatic hydrocarbons, 0 to 6 % (m/m) tri+-aromatichydrocarbons, 0 to 2

8、6 % (m/m) polycyclic aromatic hydrocar-bons, and 4 to 65 % (m/m) total aromatic hydrocarbons.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,

9、this 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

10、the 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 c

11、ontaining 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 ap

12、plica-bility of regulatory limitations prior to use.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0C on Liquid Chromatography.This test method is based on material published in IP Standard

13、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 Nov. 1, 2006. Published December 2006. Origin

14、allyapproved in 2000. Last previous edition approved in 2000 as D 6591 00.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2. Referenced Documents2.1 ASTM Standards:2D

15、1319 Test Method for Hydrocarbon Types in LiquidPetroleum Products by Fluorescent Indicator AdsorptionD 2425 Test Method for Hydrocarbon Types in MiddleDistillates by Mass SpectrometryD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petr

16、oleum andPetroleum ProductsD 5186 Test Method for Determination of the AromaticContent and PolynuclearAromatic Content of Diesel Fuelsand Aviation Turbine Fuels By Supercritical Fluid Chro-matographyD 6379 Test Method for Determination of Aromatic Hydro-carbon Types in Aviation Fuels and PetroleumDi

17、stillatesHigh Performance Liquid ChromatographyMethod with Refractive Index Detection2.2 IP Standard:3IP 548 Test Method for Determination of Aromatic Hydro-carbon Types in Middle Distillates High PerformanceLiquid Chromatography Method with Refractive IndexDetection3. Terminology3.1 Definitions of

18、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 hydrocarbons.3.1.2 mono-

19、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,compounds that have a

20、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 test method,sum o

21、f 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 specified polar column

22、have 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: benzenes, tetralin

23、s,indanes, thiophenes, and conjugated poly-alkenes, (3) DAHs:naphthalenes, biphenyls, indenes, fluorenes, acenaphthenes,and benzothiophenes and dibenzothiophenes, (4) T+AHs:phenanthrenes, pyrenes, fluoranthenes, chrysenes, triph-enylenes, and benzanthracenes.4. Summary of Test Method4.1 A known mass

24、 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 aromatichydrocarbons. As

25、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 the T+AHs as a

26、 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 are compared

27、 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 aromaticcontent

28、 (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) regulates the ar

29、omatic 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.5.3 This test m

30、ethod is applicable to materials in the sameboiling range as motor diesel fuels and is unaffected by fuelcoloration. Test Method D 1319, which has been mandated bythe US EPA for the determination of aromatics in motor dieselfuel, excludes materials with final boiling points greater than315C (600F) f

31、rom its scope. Test Method D 2425 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 D 5186,currently specified by CARB, is also applicable to the deter-mination of both

32、total aromatics and polynuclear aromatichydrocarbons in diesel fuel. Test Method D 5186, however,specifies the use of supercritical fluid chromatography equip-ment that may not be readily available.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service

33、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Institute of Petroleum, 61 New Cavendish St., London, WIM8AR, UK.D6591062NOTE 2Test Method D 5186 was previously specified by CARB as analternative

34、 to Test Method D 1319.6. Apparatus6.1 High Performance Liquid Chromatograph (HPLC)Any HPLC capable of pumping the mobile phase at flow ratesbetween 0.5 and 1.5 mL/min, with a precision better than 0.5 %and a pulsation of 1 %.6.2.1 An equal and constant volume of the calibration andsample solutions

35、shall be injected into the chromatograph.Both manual and automatic sample injection systems (usingeither complete or partial filling of the sample loop) will, whenused correctly, meet the repeatability requirements laid downin 6.2. When using the partial loop-filling mode, it is recom-mended that th

36、e injection volume should be less than half thetotal loop volume. For complete filling of the loop, best resultsare obtained by overfilling the loop at least six times.NOTE 3The repeatability of the injection system may be checked bycomparing peak areas from at least four injections of the systemper

37、formance standard (see 9.3).6.2.2 Sample and calibration injection volumes other than10 L (typically in the range from 3 to 20 L) may be used,provided they meet the requirements laid down for injectionrepeatability (see 6.2), refractive index sensitivity and linearity(see 9.4.2 and 10.1.5), and colu

38、mn resolution (see 9.4.3).6.3 Sample Filter, if required (see 10.2.1)A microfilter ofporosity 0.45 m or less, which is chemically-inert towardshydrocarbon solvents, is recommended for the removal ofparticulate matter from the sample solutions.6.4 Column SystemAny stainless steel HPLC column(s)packed

39、 with an approved amino-bonded (or polar amino/cyano-bonded) silica stationary phase is suitable, provided itmeets the resolution requirements laid down in 9.4.3. SeeAppendix X1 for guidance on the selection and use of suitablecolumn systems.6.5 HPLC Column OvenAny suitable HPLC column oven(block he

40、ating or air circulating) capable of maintaining aconstant temperature (6 1C) within the range from 20 to40C.NOTE 4The refractive index detector is sensitive to both sudden andgradual changes in the temperature of the eluent. All necessary precau-tions should be taken to establish constant temperatu

41、re conditionsthroughout the liquid chromatograph system. The temperature should beoptimized depending on the stationary phase.NOTE 5Alternative forms of temperature control, for example,temperature-controlled laboratories, are permitted.6.6 Backflush ValveAny manual or automatic (air orelectrically

42、actuated) flow-switching valve designed for use inHPLC systems that is capable of operating at pressures up to2 3 104kPa.6.7 Refractive Index DetectorAny refractive index detec-tor may be used provided it is capable of being operated overthe refractive index range from 1.3 to 1.6, meets the sensitiv

43、ityrequirement specified in 9.4.2, gives a linear response over thecalibration range, and has a suitable output signal for the datasystem.NOTE 6If the refractive index detector has a facility for independenttemperature control, it is recommended that this be set at the sametemperature as the column

44、oven.6.8 Computer or Computing IntegratorAny data systemcan be used provided it is compatible with the refractive indexdetector, has a minimum sampling rate of 1 Hz, and is capableof peak area and retention time measurement. The data systemshould also have minimum facilities for post-analysis datapr

45、ocessing, such as baseline correction and reintegration. Theability to perform automatic peak detection and identificationand to calculate sample concentrations from peak area mea-surements is recommended but not essential.6.9 Volumetric Flasks, Grade B or better, of 10 and 100 mLcapacity.6.10 Analy

46、tical Balance, accurate to 60.0001 g.7. Reagents7.1 Cyclohexane, 99 % pure.NOTE 7Cyclohexane may contain 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

47、batch variation of the solvent quality in terms ofwater content, viscosity, refractive index and purity 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 th

48、e HPLC mobile phasebefore use; this can be done conveniently, on-line, or off-line by heliumsparging, vacuum degassing or ultrasonic agitation. A failure 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 Phen

49、anthrene, $98 % pure.7.6 Dibenzothiophene, $ 95 % pure.7.7 9-Methylanthracene, $ 95 % pure. (WarningGlovesshould 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 commodity specifica-tion, samples are taken by following Practice D 4057 orD 4177, or a similar standard. In certain situations, sampling isdone in accordance with the require