1、Designation: D5186 03 (Reapproved 2009)D5186 15Standard Test Method forDetermination of the Aromatic Content and PolynuclearAromatic Content of Diesel Fuels and Aviation Turbine FuelsBy Supercritical Fluid Chromatography1This standard is issued under the fixed designation D5186; the number immediate
2、ly 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.1. Scope Scope*1.1 Th
3、is test method covers the determination of the total amounts of monoaromatic and polynuclear aromatic hydrocarboncompounds in motor diesel fuels, aviation turbine fuels, and blend stocks by supercritical fluid chromatography (SFC). The rangeof aromatics concentration to which this test method is app
4、licable is from 1 to 75 mass %. The range of polynuclear aromatichydrocarbon concentrations to which this test method is applicable is from 0.5 to 50 mass %.1.2 The values stated in SI units are to be regarded as standard. The values stated in inch-pound units are for information only.1.3 This stand
5、ard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM
6、 Standards:2D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator AdsorptionD1655 Specification for Aviation Turbine FuelsD2425 Test Method for Hydrocarbon Types in Middle Distillates by Mass SpectrometryD6299 Practice for Applying Statistical Quality Assuranc
7、e and Control Charting Techniques to Evaluate Analytical Measure-ment System Performance3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 critical pressure, nthat pressure needed to condense a gas at the critical temperature.3.1.2 critical temperature, nthe highest temperature a
8、t which a gaseous fluid may be converted to a liquid by means ofcompression.3.1.3 mononuclear aromatic hydrocarbons, nhydrohydrocarboncarbon compounds containing exactly one aromatic ring. Thisgroup includes benzene, alkyl-substituted benzenes, indans, tetralins, alkyl-substituted indans, and alkyl-
9、substituted tetralins.3.1.4 polynuclear aromatic hydrocarbons, nall hydrocarbon compounds containing two or more aromatic rings. These ringsmay be fused as in naphthalene and phenanthrene, or separate as in biphenyl.3.1.5 restrictor, na device, attached to the outlet of a chromatographic column, to
10、restrict the mobile phase flow such that themobile phase is maintained in the supercritical state throughout the chromatographic column.3.1.6 supercritical fluid, na fluid maintained in a thermodynamic state above its critical temperature and critical pressure.3.1.7 supercritical fluid chromatograph
11、y, na class of chromatography that employs supercritical fluids as mobile phases.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0C on Liquid Chromatography.Current
12、edition approved April 15, 2009April 1, 2015. Published July 2009June 2015. Originally approved in 1991. Last previous edition approved in 20032009 asD5186D5186 03 (2009).03. DOI: 10.1520/D5186-03R09.10.1520/D5186-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM
13、 Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made
14、to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Sum
15、mary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A small aliquot of the fuel sample is injected onto a packed silica adsorption column and eluted u
16、sing supercritical carbondioxide mobile phase. Monoaromatics and polynuclear aromatics in the sample are separated from nonaromatics and detectedusing a flame ionization detector.4.2 The detector response to hydrocarbons is recorded throughout the analysis time. The chromatographic areas correspondi
17、ngto the monoaromatic, polynuclear aromatic, and nonaromatic components are determined and the mass % content of each of thesegroups in the fuel is calculated by area normalization.5. Significance and Use5.1 The aromatic hydrocarbon content of motor diesel fuels is a factor that can affect their cet
18、ane number and exhaust emissions.The aromatic hydrocarbon content and the naphthalenes content of aviation turbine fuels affect their combustion characteristics andsmoke-forming tendencies. These properties represent specifications for aviation turbine fuels (see Specification D1655).5.2 The United
19、States Environmental Protection Agency (USEPA) regulates the aromatic content of diesel fuels. California AirResources Board (CARB) regulations place limits on the total aromatics content and polynuclear aromatic hydrocarbon contentof motor diesel fuel, thus requiring an appropriate analytical deter
20、mination to ensure compliance with the regulations. Producersof diesel fuels will require similar determinations for process and quality control. This test method can be used to make suchdeterminations.5.3 This test method is applicable to materials in the boiling range of motor diesel fuels and is
21、unaffected by fuel coloration.Test Method D1319, which has been mandated by the USEPA for the determination of aromatics in motor diesel fuel, excludesmaterials with final boiling points greater than 315C (600F)315 C (600 F) from its scope. Test Method D2425 is applicable tothe determination of both
22、 total aromatics and polynuclear aromatic hydrocarbons in diesel fuel, but is much more costly andtime-consuming to perform.5.4 Results obtained by this test method have been shown to be statistically more precise than those obtained from Test MethodD1319 for typical diesel fuels, and this test meth
23、od has a shorter analysis time.3 Cooperative study data4 have found this testmethod to be more precise than the published precision of Test Method D1319 when applied to aviation turbine fuels and dieselfuels. Results from this test method for total polynuclear aromatic hydrocarbons are also expected
24、 to be at least as precise as thoseof Test Method D2425.6. Apparatus6.1 Supercritical Fluid Chromatograph (SFC)Any SFC instrumentation can be used that has the following capabilities andmeets the performance requirements in Section 8.6.1.1 PumpThe SFC instrumentation must include a pump capable of d
25、elivering supercritical carbon dioxide to the columnwithout pressure fluctuations and at constant flow. The pump is typically a single-stroke-type (syringe) pump or a highly dampenedreciprocating pump with pressure fluctuations not exceeding 60.3 % of the operating pressure.6.1.2 DetectorThis test m
26、ethod is limited to the use of the flame ionization detector (FID). The detector must have sufficientsensitivity to detect 0.1 mass % toluene in hexadecane under instrument conditions employed in this test method.6.1.3 Column Temperature ControlThe chromatograph must be capable of column temperature
27、 control of at least 60.5C(1F)60.5 C (1 F) at the operating temperature.6.1.4 Sample Inlet SystemA liquid sample injection valve is required, capable of reproducibly introducing samples in the0.050.05 Lto 0.50-L0.50 Lliquid volume range. The inlet system should be operated at between 2525 C and 30C.
28、30 C. Thesample inlet system must be connected to the chromatographic column so that loss of chromatographic efficiency is avoided.6.1.5 Post-column RestrictorAdevice capable of maintaining mobile phase supercritical conditions within the column and upto the detector inlet must be connected to the e
29、nd of the column.6.1.6 ColumnAny liquid or supercritical fluid chromatographic column may be used that provides separation of nonaromatic,monoaromatic, and polynuclear aromatic hydrocarbons and meets the performance requirements of Section 8. Some columns andconditions that have been used successful
30、ly are shown in Table 1.6.1.7 IntegratorMeans must be provided for the determination of both discrete chromatographic peak areas and theaccumulated area under the chromatogram. This can be done by means of a computer or electronic integrator. The computer orintegrator must have the capability of cor
31、recting for baseline shifts during the run.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Soc
32、iety where such3 Supporting data (obtained in a comparison study of Test Methods D1319 and D5186) have been filed at ASTM International Headquarters and may be obtained byrequesting Research Report RR:D02-1276.4 Supporting data have been filed at ASTM International Headquarters and may be obtained b
33、y requesting Research Report RR:D02-1388.D5186 152specifications are available.5 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto permit its use without lessening the accuracy of the determination.7.2 AirZero grade (hydrocarbon-free) is use
34、d as the FID oxidant. (WarningAir is usually supplied as a compressed gasunder high pressure and supports combustion.)7.3 Carbon Dioxide (CO2) Supercritical fluid chromatographic grade, 99.99 % minimum purity, supplied pressurized in acylinder equipped with a dip tube for removal of liquid CO2. (War
35、ningLiquid at high pressure. Release of pressure results inproduction of extremely cold solid CO2 and gas, which can dilute available atmospheric oxygen.)7.4 Check StandardA commercial standard reference material, which has accepted reference values, in accordance with inSection 6 on Reference Mater
36、ials in Practice D6299. Alternatively, samples subjected to round robin may be used as checkstandards. It is important that the standard deviation of the values of the laboratory exchange program not be statistically greaterthan the reproducibility for the test method.7.5 HydrogenHydrogen of high qu
37、ality (hydrocarbon-free) is used as the fuel for the flame ionization detector. (WarningHydrogen is usually supplied under high pressure and is extremely flammable.)7.6 Performance MixtureAquantitative mixture of approximately 75 mass % hexadecane (n-C16), 20 mass % toluene, 3 mass% tetralin (1,2,3,
38、4-tetrahydronaphthalene), and 2 mass % naphthalene is used for performance checks.7.7 Quality Control SampleA homogeneous material having similar physical and chemical properties to the samples to beanalyzed. The choice of such material should be guided by Section 6 on Reference Materials in Practic
39、e D6299. Examples of suchmaterial can be motor diesel fuel, aviation turbine fuel or other typical samples containing aromatics and polynuclear aromaticssimilar to the samples to be analyzed.8. Preparation of Apparatus8.1 Install the SFC instrumentation in accordance with the manufacturers instructi
40、ons. System operating conditions will dependupon the column used and optimization of performance. Conditions listed in Table 1 have been used successfully. If theperformance characteristics in terms of retention and resolution, specified in 8.2, are not achieved, modify the temperature,pressure, or
41、mobile phase flow rate to achieve compliance. A column of low activity may be reactivated by solvent rinsing usingestablished liquid chromatography activation techniques.NOTE 1This temperature can be increased (up to 40C)40 C) if the resolution between the monoaromatics and polynuclear aromatics is
42、notsatisfactory. Lower temperatures are suggested to improve resolution between nonaromatics and monoaromatics.8.2 System Performance:8.2.1 ResolutionAnalyze the performance mixture prepared in 7.6. The resolution between the nonaromatics and monoaro-matics (RNM) must be at least four and resolution
43、 between the monoaromatics and polynuclear aromatics (RMD) must be at leasttwo when calculated in accordance with the following equations:RNM5 23t22t1!1.6993y21y 1!(1)RMD523t 42t3!1.6993y 41y3! (2)where:t 1 = time for the n-C16 peak apex, s,t2 = time for the toluene peak apex, s,t3 = time for the te
44、tralin peak apex, s,t4 = time for the naphthalene peak apex, s,y 1 = peak width at half height of n-C16 peak, s,y 2 = peak width at half height of toluene, s,y3 = peak width at half height of tetralin, s, andy4 = peak width at half height of naphthalene, s.8.2.2 Retention Time Reproducibility Repeat
45、ed injections of the performance mixture must show a retention time repeatability(maximum difference between duplicate runs) of not more than 0.5 % for n-C16 and toluene peaks.8.2.3 Detector Accuracy TestThis test method assumes that the FID response approximates the theoretical unit carbonresponse.
46、 To verify this assumption, analyze the performance mixture and calculate the response factors, relative to hexadecane( RRFi), for each of the components in the performance mix, using the following equations:5 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Wa
47、shington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D5186
48、 153RFi 5 AiMi(3)RRFi 5RF iRFC16 (4)where:Ai = Component i in performance mix, area %,Mi = Component i in performance mix, known mass %,RFi = response factor of Component i,RFC16 = response factor of hexadecane in performance mix, andRRFi = relative response factor of Component i.These values can th
49、en be compared to the theoretical response factor for each component in the performance mix as calculatedby the following equation:RRFtheo5S12.013nMW D 3S 226.412.01316D (5)where:12.01 = atomic mass of carbon,n = number of carbon atoms in component molecule,MW = molecular mass of component,226.4 = molecular mass of hexadecane, and16 = number of carbon atoms in hexadecane molecule.The measured RRF for each component in the test mixture must be within 610 % of the theoretical value as calculated withEq 5 or summarized in Table 21.
