1、Designation: D 7398 07An American National StandardStandard Test Method forBoiling Range Distribution of Fatty Acid Methyl Esters(FAME) in the Boiling Range from 100 to 615C by GasChromatography1This standard is issued under the fixed designation D 7398; the number immediately following the designat
2、ion 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.1. Scope1.1 This test method covers the deter
3、mination of the boilingrange distribution of fatty acid methyl esters (FAME). This testmethod is applicable to FAMES (biodiesel, B100) having aninitial boiling point greater than 100C and a final boiling pointless than 615C at atmospheric pressure as measured by thistest method.1.2 The test method c
4、an also be applicable to blends ofdiesel and biodiesel (B1 through B100), however precision forthese samples types has not been evaluated.1.3 The test method is not applicable for analysis ofpetroleum containing low molecular weight components (forexample naphthas, reformates, gasolines, crude oils)
5、.1.4 Boiling range distributions obtained by this test methodare not equivalent to results from low efficiency distillationsuch as those obtained with Test Method D86 or D 1160,especially the initial and final boiling points.1.5 This test method uses the principles of simulated distil-lation methodo
6、logy. See Test Methods D 2887, D 6352, andD 7213.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibil
7、ity of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD 1160 Test Method fo
8、r Distillation of Petroleum Productsat Reduced PressureD 2887 Test Method for Boiling Range Distribution ofPetroleum Fractions by Gas ChromatographyD 2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Plate Column)D 4626 Practice for Calculation of Gas ChromatographicResponse Factor
9、sD 6352 Test Method for Boiling Range Distribution ofPetroleum Distillates in Boiling Range from 174 to 700Cby Gas ChromatographyD 6751 Specification for Biodiesel Fuel Blend Stock(B100) for Middle Distillate FuelsD 7213 Test Method for Boiling Range Distribution ofPetroleum Distillates in the Boili
10、ng Range from 100 to615C by Gas ChromatographyE 355 Practice for Gas Chromatography Terms and Rela-tionshipsE 594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE 1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatog
11、raphs3. Terminology3.1 Definitions:3.1.1 This test method makes reference to many commongas chromatographic procedures, terms, and relationships.Detailed definitions of these can be found in Practices E 355,E 594, and E 1510.3.1.2 biodiesel, nfuel composed of mono-alkyl esters oflong chain fatty aci
12、ds derived from vegetable oils or animalfats, designated B100.3.2 Definitions of Terms Specific to This Standard:3.2.1 area slice, narea resulting from the integration ofthe chromatographic detector signal within a specified reten-tion time interval. In area slice mode (6.4.2), peak detection1This t
13、est method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0H on Chromatographic Distribution Methods.Current edition approved Nov. 1, 2007. Published December 2007.2For referenced ASTM standards, visit the AS
14、TM website, www.astm.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unit
15、ed States.Copyright by ASTM Intl (all rights reserved); Wed May 20 03:18:30 EDT 2009Downloaded/printed byGuo Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.parameters are bypassed and the detector signal integral isrecorded as area slices of consecutive, fixed durati
16、on timeintervals.3.2.2 atmospheric equivalent temperature (AET),ntemperature converted from the measured vapor tempera-ture obtained at sub-ambient pressure to atmospheric equiva-lent temperature (AET) corresponding to the equivalent boilingpoint at atmospheric pressure, 101.3 kPa (760 mm Hg), TheAE
17、T is the expected distillate temperature if the distillationwas performed at atmospheric pressure and there was nothermal decomposition.3.2.3 corrected area slice, narea slice corrected for base-line offset, by subtraction of the exactly corresponding areaslice in a previously recorded blank (non-sa
18、mple) analysis.3.2.4 cumulative corrected area, naccumulated sum ofcorrected area slices from the beginning of the analysis througha given retention time, ignoring any non-sample area (forexample, solvent).3.2.5 initial boiling point (IBP), ntemperature (corre-sponding to the retention time) at whic
19、h a cumulative correctedarea count equal to 0.5 % of the total sample area under thechromatogram is obtained.3.2.6 final boiling point (FBP), ntemperature (corre-sponding to the retention time) at which a cumulative correctedarea count equal to 99.5 % of the total sample area under thechromatogram i
20、s obtained.3.2.7 slice rate, nfrequency of data sampling or thefrequency of data bunching provided that the frequency of dataacquisition is larger than the frequency of bunching. The unitof frequency is points/seconds or Hz.3.2.8 slice time, ncumulative slice rate (analysis time)associated with each
21、 area slice throughout the chromatographicanalysis. The slice time is the time at the end of eachcontiguous area slice.3.2.9 total sample area, ncumulative corrected area, fromthe initial point to the final area point.3.3 Abbreviations:3.3.1 Acommon abbreviation of hydrocarbon compounds isto designa
22、te the number of carbon atoms in the compound. Aprefix is used to indicate the carbon chain form, while asubscripted suffix denotes the number of carbon atoms (forexample, normal decane n-C10; iso-tetradecane = i-C14).3.3.2 A common abbreviation for FAME compounds is todesignate the number of carbon
23、 atoms and number of doublebonds in the compound. The number of carbon atoms isdenoted by a number after the “C” and the number followinga colon indicates the number of double bonds (for example,C16:2; FAME with 16 carbon atoms and 2 double bonds).4. Summary of Test Method4.1 The boiling range distr
24、ibution by distillation is simu-lated by the use of gas chromatography. A non-polar opentubular (capillary) gas chromatographic column is used to elutethe hydrocarbon and FAME components of the sample in orderof increasing boiling point.4.2 A sample aliquot is diluted with a viscosity reducingsolven
25、t and introduced into the chromatographic system. Thesolvent shall be apolar and not interfere with measurement ofthe sample in the 100 to 615C range. Sample vaporization isprovided by separate heating of the point of injection or inconjunction with column oven heating.4.3 The column oven temperatur
26、e is raised at a reproduciblelinear rate to effect separation of the FAME components inorder of increasing boiling point relative to a n-paraffincalibration mixture. The elution of sample components isquantitatively determined using a flame ionization detector.The detector signal integral is recorde
27、d as area slices forconsecutive retention time intervals during the analysis.4.4 Retention times of known normal paraffin hydrocarbons,spanning the scope of the test method (C5C60), are deter-mined and correlated to their boiling point temperatures. Thenormalized cumulative corrected sample areas fo
28、r each con-secutive recorded time interval are used to calculate the boilingrange distribution. The boiling point temperature at eachreported percent off increment is calculated from the retentiontime calibration.4.5 The retention time versus boiling point curve is cali-brated with normal paraffin h
29、ydrocarbons since these boilingpoints are well defined. A mixture of FAMEs is analyzed tocheck column resolution. A triglyceride is analyzed to verifythe systems ability to detect unreacted oil.5. Significance and Use5.1 The boiling range distribution of FAMES provides aninsight into the composition
30、 of product related to the transes-terification process. This gas chromatographic determination ofboiling range can be used to replace conventional distillationmethods for product specification testing with the mutualagreement of interested parties.5.2 Biodiesel (FAMES) exhibits a boiling point rath
31、er thana distillation curve. The fatty acid chains in the raw oils andfats from which biodiesel is produced are mainly comprised ofstraight chain hydrocarbons with 16 to 18 carbons that havesimilar boiling temperatures. The atmospheric boiling point ofbiodiesel generally ranges from 330 to 357C. The
32、 Specifica-tion D 6751 value of 360C max at 90 % off by Test MethodD 1160 was incorporated as an precaution to ensure the fuelhas not been adulterated with high boiling contaminants.6. Apparatus6.1 ChromatographThe following gas chromatographicsystem performance characteristics are required:6.1.1 Co
33、lumn OvenCapable of sustained and linear pro-grammed temperature operation from near ambient (for ex-ample 35 to 50C) up to 400C.6.1.2 Column Temperature ProgrammerThe chromato-graph must be capable of linear programmed temperatureoperation up to 400C at selectable linear rates up to 20C/min.The pro
34、gramming rate must be sufficiently reproducible toobtain the retention time repeatability of 0.03 min (3 s) for eachcomponent in the calibration mixture described in 7.3.6.1.3 DetectorThis test method requires a flame ioniza-tion detector (FID). The detector must meet or exceed thefollowing specific
35、ations as detailed in Practice E 594. Thespecification of flame jet orifice is approximately 0.45 mm(0.018 in.).6.1.3.1 Operating Temperature, 400C.6.1.3.2 Sensitivity, 0.005 coulombs/ g carbon.D7398072Copyright by ASTM Intl (all rights reserved); Wed May 20 03:18:30 EDT 2009Downloaded/printed byGuo
36、 Dehua (CNIS) pursuant to License Agreement. No further reproductions authorized.6.1.3.3 Minimum Detectability,13 10-11g carbon / s.6.1.3.4 Linear Range, 1066.1.3.5 Connection of the column to the detector must besuch that no temperature below the column temperature exists.Refer to Practice E 1510 f
37、or proper installation and condition-ing of the capillary column.6.1.4 Sample Inlet SystemAny sample inlet system ca-pable of meeting the performance specification in 6.1.5 and 7.3may be used. Programmed temperature vaporization (PTV)and programmable cool on-column injection systems havebeen used su
38、ccessfully.6.1.5 Carrier Gas Flow ControlThe chromatograph shallbe equipped with carrier flow control capable of maintainingconstant carrier gas flow control through the column through-out the column temperature program cycle as measured withthe use of flow a sensor. Flow rate must be maintained wit
39、hin1 % through out the temperature program.6.2 MicrosyringeA microsyringe with a 23 gauge orsmaller stainless steel needle is used for on-column sampleintroduction. Syringes of 0.1 to 10 L capacity are available.6.2.1 Automatic syringe injection is recommended toachieve best precision.6.3 ColumnThis
40、 test method is limited to the use ofnon-polar wall coated open tubular (WCOT) columns of highthermal stability. Glass, fused silica, and stainless steel col-umns, with a 0.53 mm diameter have been successfully used.Cross-linked or bonded 100 % dimethyl-polysiloxane station-ary phases with film thic
41、kness of 0.5 to 1.0 m have been used.The column length and liquid phase film thickness shall allowthe elution of at least C60n-paraffin (BP = 615C) and triolein.The column and conditions shall provide separation of typicalpetroleum hydrocarbons and saturated FAMES in order ofincreasing boiling point
42、 and meet the column resolutionrequirements of 8.2.1. The column shall provide a resolutionbetween five (5) and fifteen (15) using the test methodoperating conditions.6.4 Data Acquisition System:6.4.1 RecorderA 0 to 1 mV range recording potentiom-eter or equivalent, with a full-scale response time o
43、f2sorlessmay be used to provide a graphical display.6.4.2 IntegratorMeans shall be provided for determiningthe accumulated area under the chromatogram. This can bedone by means of an electronic integrator or computer basedchromatography data system. The integrator/computer systemshall have normal ch
44、romatographic software for measuring theretention time and areas of eluting peaks (peak detectionmode). In addition, the system shall be capable of convertingthe continuously integrated detector signal into area slices offixed duration (area slice mode). These contiguous area slices,collected for th
45、e entire analysis, are stored for later processing.The electronic range of the integrator/computer (for example, 1V, 10 V) shall be operated within the linear range of thedetector/electrometer system used.NOTE 1Some gas chromatographs have an algorithm built into theiroperating software that allows
46、a mathematical model of the baselineprofile to be stored in memory. This profile is automatically subtractedfrom the detector signal on subsequent sample runs to compensate for thecolumn bleed. Some integration systems also store and automaticallysubtract a blank analysis from subsequent analytical
47、determinations.7. Reagents and Materials7.1 GasesThe following compressed gases are utilized forthe operation of the gas chromatograph.7.1.1 Helium, 99.999 %. (WarningCompressed gas un-der high pressure.) This gas can be used as carrier gas. Ensuresufficient pressure for a constant carrier gas flow
48、rate. It is notto contain more than 5 mL/m3of oxygen and the total amountof impurities are not to exceed 10 mL/m3.7.1.2 Nitrogen, 99.999 %. (WarningCompressed gas un-der high pressure.) This gas can be used as carrier gas. Ensuresufficient pressure for a constant carrier gas flow rate. It is notto c
49、ontain more than 5 mL/m3of oxygen and the total amountof impurities are not to exceed 10 mL/m3.7.1.3 Hydrogen, 99.999 %. (WarningExtremely flam-mable gas under high pressure.) The total impurities are not toexceed 10 mL/m3. This gas can be used as carrier gas. Ensuresufficient pressure for a constant carrier gas flow rate. It is alsoused as fuel for the flame ionization detector (FID).7.1.4 Air, 99.999 %. (WarningCompressed gas underhigh pressure and supports combustion.) Total impurities arenot to exceed 10 mL/m3. This gas is used to sustai
