ASTM D6379-2004 Standard Test Method for Determination of Aromatic Hydrocarbon Types in Aviation Fuels and Petroleum Distillates&8212 High Performance Liquid Chromatography Method .pdf

1、Designation: D 6379 04Designation: 436/01An American National StandardStandard Test Method forDetermination of Aromatic Hydrocarbon Types in AviationFuels and Petroleum DistillatesHigh Performance LiquidChromatography Method with Refractive Index Detection1This standard is issued under the fixed des

2、ignation D 6379; the number 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 revisi

3、on or reapproval.INTRODUCTIONThis test method is intended to be technically equivalent to IP 436-01 with an identical title. 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

4、one of several possible 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 t

5、he user to determine such correlation if necessary.1. Scope*1.1 This test method covers a high performance liquidchromatographic test method for the determination of mono-aromatic and di-aromatic hydrocarbon contents in aviationkerosines and petroleum distillates boiling in the range from 50to 300C,

6、 such as Jet A or Jet A-1 fuels. The total aromaticcontent is calculated from the sum of the individual aromatichydrocarbon-types.NOTE 1Samples with a final boiling point greater than 300C thatcontain tri-aromatic and higher polycyclic aromatic compounds are notdetermined by this test method and sho

7、uld be analyzed by Test MethodD 6591 or other suitable equivalent test methods.1.2 This test method is calibrated for distillates containingfrom 10 to 25 % m/m mono-aromatic hydrocarbons and from0 to 7 % m/m di-aromatic hydrocarbons.1.3 The precision of this test method has been establishedfor keros

8、ine boiling range distillates containing from 10 to25 % m/m mono-aromatic hydrocarbons and from 0 to 7 %m/m di-aromatic hydrocarbons.1.4 Compounds containing sulfur, nitrogen, and oxygen arepossible interferents. Mono-alkenes do not interfere, but con-jugated di- and poly-alkenes, if present, are po

9、ssible interfer-ents.1.5 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. Re

10、ferenced Documents2.1 ASTM Standards:2D 4052 Test Method for Density and Relative Density ofLiquids by Digital Density MeterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 6591 Test Method for Determinat

11、ion of Aromatic Hydro-carbon Types in Middle DistillatesHigh PerformanceLiquid Chromatography Method with Refractive IndexDetection1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarb

12、on Analysis.Current edition approved May 1, 2004. Published June 2004. Originallyapproved in 1999. Last previous edition approved in 1999 as D 637999.In the IP, this test method is under the jurisdiction of the StandardizationCommittee.2For referenced ASTM standards, visit the ASTM website, www.astm

13、.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Bo

14、x C700, West Conshohocken, PA 19428-2959, United States.2.2 Energy Institute Standards:3IP 436 Test Method for Determination of Automatic Hydro-carbon Types in Aviation Fuels and Petroleum Distillates-High Performance Liquid Chromatography Method withRefractive Index3. Terminology3.1 Definitions of

15、Terms Specific to This Standard:3.1.1 di-aromatic hydrocarbons (DAHs), ncompoundsthat have a longer retention time on the specified polar columnthan the MAHs.3.1.2 mono-aromatic hydrocarbons (MAHs),ncompounds that have a longer retention time on thespecified polar column than the non-aromatic hydroc

16、arbons buta shorter retention time than the di-aromatic hydrocarbons.3.1.3 non-aromatic hydrocarbons, ncompounds that havea shorter retention time on the specified polar column than themono-aromatic hydrocarbons.3.1.4 total aromatic hydrocarbons, nsum of the MAHsand DAHs.NOTE 2The elution characteri

17、stics of aromatic and non-aromaticcompounds on the specified polar column have not been specificallydetermined for this test method. Published and unpublished data indicatethe major constituents for each hydrocarbon type as follows: (1) Non-aromatic hydrocarbons: acyclic and cyclic alkanes (paraffin

18、s and naph-thenes), mono-alkenes (if present). (2) MAHs: benzenes, tetralins, in-danes, thiophenes, conjugated poly-alkenes. (3) DAHs: naphthalenes,biphenyls, indenes, fluorenes, acenaphthenes, benzothiophenes.4. Summary of Test Method4.1 The test portion is diluted 1:1 with the mobile phase,such as

19、 heptane, and a fixed volume of this solution injectedinto a high performance liquid chromatograph fitted with apolar column. This column has little affinity for the non-aromatic hydrocarbons and exhibits a pronounced selectivityfor aromatic hydrocarbons. As a result of this selectivity, thearomatic

20、 hydrocarbons are separated from the non-aromatichydrocarbons into distinct bands in accordance with their ringstructure, that is, MAHs and DAHs.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

21、 is continually monitored bya data processor. The amplitudes of the signals (peak areas)from the sample aromatics are compared with those obtainedfrom previously-run calibration standards in order to calculatethe percent m/m MAHs and DAHs in the sample. The sum ofthe MAHs and DAHs is reported as the

22、 total aromatic content(percent m/m) of the sample.5. Significance and Use5.1 Accurate quantitative information on aromatic hydro-carbon types can be useful in determining the effects ofpetroleum processes on production of various finished fuels.This information can also be useful for indicating the

23、 quality offuels and for assessing the relative combustion properties offinished fuels.6. Apparatus6.1 High Performance Liquid Chromatograph (HPLC)Any high performance liquid chromatograph capable of pump-ing the mobile phase at flow rates between 0.5 and 1.5 mL/min3Available from Energy Institute,

24、61 New Cavendish St., London, WIG 7AR,U.K.FIG. 1 Example Chromatogram of an Aviation Fuel Showing Integration Points and Aromatic Hydrocarbon Type GroupsD6379042with a precision better than 0.5 % and a pulsation of 99 % pure.NOTE 5Cyclohexane may contain benzene as an impurity.7.2 Heptane, HPLC Grad

25、e. For use as HPLC mobile phase.(WarningHydrocarbon solvents are highly flammable andmay cause irritation by inhalation, ingestion, or skin contact.)NOTE 6It is recommended practice to degas the HPLC mobile phasebefore use.7.3 1-Methylnaphthalene, $ 98 % pure. (WarningGloves should be worn when hand

26、ling aromatic compounds(for example, disposable vinyl gloves).)NOTE 7Purity is determined by gas chromatography with flameionization detection. The highest purity standards available should beused. Standards of $ 98 % purity are commercially available from allmajor suppliers.7.4 o-Xylene (1,2-Dimeth

27、ylbenzene), $ 98 % pure.8. Sampling8.1 The laboratory fuel sample from which an aliquot isbeing drawn for the purposes of this test method shall berepresentative of the lot of fuel. The laboratory sample shouldbe obtained by following Practice D 4057 or D 4177, or asimilar standard.9. Apparatus Prep

28、aration9.1 Set up the chromatograph, injection system, column andcolumn oven, refractive index detector, and computing inte-grator in accordance with the appropriate equipment manuals.The HPLC column shall be installed in the column oven.NOTE 8The column oven is optional if alternative arrangements

29、aremade to maintain a constant temperature environment, for example, atemperature-controlled laboratory (see 6.5).9.2 Adjust the flow rate of the mobile phase to a constant 1.06 0.2 mL/min and ensure that the reference cell of therefractive index detector is full of mobile phase (see 6.6.1).Allow th

30、e temperature of the column oven (and refractiveindex detector if equipped with temperature control) to stabi-lize.9.2.1 To minimize drift, it is essential to make sure that thereference cell is full of solvent. The best way to accomplish thisis either to (1) flush the mobile phase through the refer

31、ence cell(then isolate the reference cell to prevent evaporation of thesolvent) immediately prior to analysis, or (2) continuouslymake up for solvent evaporation by supplying a steady flowthrough the reference cell. The makeup flow is optimized sothat reference and analytical cell mismatch due to dr

32、ying-out,temperature, or pressure gradients are minimized. Typically4Stationary phases known to give suitable results include Spherisorb 3NH2,Spherisorb 5NH2, Partisil 5 PAC, and Partisphere 5 PAC.D6379043this can be accomplished with a makeup flow set at one tenthof the analytical flow.NOTE 9The fl

33、ow rate may be adjusted (typically within the rangefrom 0.8 to 1.2 mL/min) to an optimum value to meet the resolutionrequirements specified in 9.4.3.9.3 Prepare a system resolution standard (SRS) by weighingcyclohexane (1.0 6 0.1 g), o-xylene (0.5 6 0.05 g), and1-methylnaphthalene (0.05 6 0.005 g) i

34、nto a 100 mL volumet-ric flask and making up to the mark with heptane.NOTE 10The SRS may be kept for up to one year if stored in a tightlystoppered bottle in a dark place between 5 and 25C.9.4 When operating conditions are steady, as indicated by astable horizontal baseline, inject 10 L of the SRS (

35、see 9.3) andrecord the chromatogram using the data system.NOTE 11Baseline drift over the period of the HPLC analysis runshould be less than 0.5 % of the peak height for cyclohexane. A baselinedrift greater than this indicates problems with the temperature control ofthe column/refractive index or pol

36、ar material eluting from the column, orboth. A period of up to 1 h may be required before the liquid chromato-graph reaches steady state conditions.9.4.1 Ensure that baseline separation is obtained between allthree components of the SRS.9.4.2 Ensure that the data system can accurately measure thepea

37、k area of 1-methylnaphthalene.NOTE 12The S/N (signal to noise) ratio for 1-methylnaphthaleneshould be 3:1 or greater.9.4.3 Ensure that the resolution between cyclohexane ando-xylene is not less than five.9.4.3.1 Column ResolutionCalculate the resolution be-tween cyclohexane and o-xylene as follows:R

38、esolution 52 3 t2 t1!1.699 3 y21 y1!(1)where:t1= retention time of cyclohexane peak in seconds,t2= retention time of o-xylene peak in seconds,y1= half-height peak width of cyclohexane in seconds, andy2= half-height peak width of o-xylene in seconds.If the resolution is less than five, check to see t

39、hat all systemcomponents are functioning correctly and that the chromato-graphic dead volume has been minimized. Adjust the flow rateto see if this improves the resolution, and make sure that themobile phase is of sufficiently high quality. Finally, regenerateor replace the column.9.5 Repeat 9.4, an

40、d ensure that the repeatabilities for peakarea measurements of o-xylene and 1-methylnaphthalene arewithin the precision of this test method.NOTE 13If peak area repeatabilities are poor, check to see that theinjection system is working optimally and that the baseline is stable(minimal drift) and nois

41、e-free.10. Procedure10.1 Calibration:10.1.1 Prepare four calibration standards (A, B, C, and D),in accordance with the concentrations given in Table 1, byweighing, to the nearest 0.0001 g, the appropriate materialsinto 100 mL volumetric flasks and making up to the mark withheptane.NOTE 14The recomme

42、nded concentrations in Table 1 will cover mostpetroleum materials distilling in the kerosine boiling range. Other standardconcentrations may be used provided they meet the requirements of thetest method (that is, linearity, detector sensitivity, and column resolution).NOTE 15The calibration standard

43、 solutions should be stored in tightlystoppered bottles (for example, 100 mL volumetric flasks) in a dark placebetween 5 and 25C. Under these conditions, the solutions are viable forat least six months.10.1.2 When operating conditions are steady (see 9.4),inject 10 L of Calibration Standard A. Recor

44、d the chromato-gram, and measure the peak areas for each aromatic standard.Ensure that baseline separation is obtained between all threecomponents.10.1.3 Repeat 10.1.2 using Calibration Standards B, C, andD.10.1.4 Plot percent m/v (g/100 mL) concentration againstarea counts for each aromatic standar

45、d, that is, o-xylene and1-methylnaphthalene. Calibration plots should be linear with acorrelation coefficient greater than 0.999 and an intercept ofless than 60.01. A computer or data system may be used tointerpret these calibrations.NOTE 16It should only be necessary to calibrate the refractive ind

46、exdetector on a daily basis.NOTE 17It is recommended that a reference kerosine or one of thefour calibration standards be run after every five samples to check thestability of the system.NOTE 18To determine % (V/V) aromatic hydrocarbon types, estab-lish % (V/V) calibration plots (mL/100 mL versus pe

47、ak area) in place of% (m/V) calibration plots (g/100 mL versus peak area). Divide the %(m/V) concentrations of o-xylene and 1-methylnaphthalene by theirrespective densities at 20C to convert to % (V/V) (mL/100 mL). See alsoNote 19 and Note 22.10.2 Analysis of Samples:10.2.1 Weigh, to the nearest 0.0

48、01 g, between 4.9 and 5.1 gof test portion into a 10 mL volumetric flask, and make up tothe mark with heptane. Shake thoroughly to mix. Allowsolution to stand for 10 min and filter (see 6.3), if necessary, toremove insoluble material.10.2.1.1 For products in which the concentration of one ormore aro

49、matic hydrocarbon types fall outside the calibrationrange, prepare a more concentrated (for example, 10 g/10 mL)or more dilute (2 g/10 mL) test portion solution as appropriate.NOTE 19To determine % (V/V) aromatic hydrocarbon types, preparea V/V dilution of the test portion by either (1) accurately pipetting 5 mLof test portion into a 10 mL volumetric flask and making up to the markwith heptane, or (2) dividing the test portion weight by its densitydetermined using Test Method D 4052 to convert to a volume. See alsoNote 18 and Note 22.TABLE 1 Concen