1、Designation: D7974 15Standard Test Method forDetermination of Farnesane, Saturated Hydrocarbons, andHexahydrofarnesol Content of Synthesized Iso-Paraffins(SIP) Fuel for Blending with Jet Fuel by GasChromatography1This standard is issued under the fixed designation D7974; the number immediately follo
2、wing 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. Scope1.1 This test method
3、covers the determination of farnesane(2,6,10-trimethyldodecane), saturated hydrocarbons, and hexa-hydrofarnesol content in synthesized iso-paraffins (SIP) fuelfor blending with jet fuel by gas chromatography.1.2 Farnesane is determined from 96 % to 99.9 % by mass.Sum of saturated hydrocarbons includ
4、ing farnesane is deter-mined from 97 % to 99.9 % by mass, and hexahydrofarnesol isdetermined from 0.02 % to 2.0 % by mass.1.3 This test method does identify and quantify mainimpurities or group type of impurities but does not purport toidentify all individual components that can be present insynthes
5、ized iso-paraffins (SIP) fuel for jet fuel blending.1.4 This test method is inappropriate for impurities that boilat temperatures higher than 460 C or for impurities that causepoor or no response in a flame ionization detector.1.5 The values stated in SI units are to be regarded asstandard. No other
6、 units of measurement are included in thisstandard.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 applica-bility of
7、regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD7566 Specification for Aviation Turbine Fuel ContainingSynthesized Hydroc
8、arbonsE355 Practice for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid Chromatography3. Terminology3.1 Definitions:3.1.1 This test method makes reference to many commongas chromatographic procedures, terms, and relati
9、onships.Detailed definitions can be found in Practices E355 and E594.3.1.2 saturated hydrocarbons, nparaffinic and naphtheniccompounds.4. Summary of Test Method4.1 A representative aliquot of the synthesized iso-paraffins(SIP) fuel sample is introduced into a gas chromatographequipped with a 5 % phe
10、nyl-methylpolysiloxane bonded phasecapillary column. Helium or hydrogen carrier gas transportsthe vaporized aliquot through the column where the compo-nents are separated by the chromatographic process. Compo-nents are sensed by a flame ionization detector as they elutefrom the column. The detector
11、signal is processed by anelectronic data acquisition system. The farnesane and itsimpurities are identified by comparing their relative retentiontimes to the ones reported in the method. Identification hasbeen previously performed analyzing reference samples bymass spectrometry under identical condi
12、tions. The concentra-tions of all components are determined in mass percent area bynormalization of the peak areas.5. Significance and Use5.1 Synthesized iso-paraffins (SIP) fuel are being approvedfor blending with jet fuel provided that they meet a purityspecification of more than 97 % farnesane, m
13、ore than 98 %saturated hydrocarbons, and less than 1.5 % hexahydrofarnesolin accordance with Specification D7566. This test method1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.0
14、4.0L on Gas Chromatography Methods.Current edition approved March 15, 2015. Published June 2015. DOI: 10.1520/D7974-15.2For 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
15、to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1provides a method of determining the percentage of farnesane(purity) in the synthesized iso-paraffins (SIP) fuel for blendingwit
16、h jet fuel.6. Apparatus6.1 Gas Chromatograph, capable of operating at the condi-tions listed in Table 1. A heated flash vaporizing injectordesigned to provide a linear sample split injection (forexample, 100:1) is required for proper sample introduction.Carrier gas controls shall be of adequate prec
17、ision to providereproducible column flows and split ratios in order to maintainanalytical integrity. A hydrogen flame ionization detector withassociated gas controls and electronics, designed for optimumresponse with open tubular columns, is required.6.2 Sample IntroductionManual or automatic liquid
18、 sy-ringe sample injection to the splitting injector is employed.Devices capable of 1.0 L injections are suitable.6.3 ColumnThis test method utilizes a fused silica opentubular column with non-polar 5 % phenyl-methylpolysiloxanebonded (cross-linked) phase internal coating.6.3.1 Open tubular column w
19、ith a non-polar 5 % phenyl-methylpolysiloxane bonded (cross-linked) phase internal coat-ing; a 30 m long by 0.25 mm internal diameter column with a0.25 m film thickness has been found to be suitable.6.4 Electronic Data Acquisition SystemAny data acquisi-tion and integration device used for quantific
20、ation of theseanalyses shall meet or exceed these minimum requirements:6.4.1 Normalized percent calculation based on peak area,6.4.2 Identification of individual components based on re-tention time,6.4.3 Noise and spike rejection capability,6.4.4 Sampling rate of 5 Hz.7. Reagents and Materials7.1 Ca
21、rrier Gas, Helium or hydrogen, with a minimumpurity of 99.9 % mol. Oxygen removal systems and gaspurifiers should be used. (WarningHelium, compressed gasunder high pressure.) (WarningHydrogen, extremely flam-mable gas under high pressure.) The use of hydrogen sensors inthe oven is strongly recommend
22、ed that can shutoff the hydro-gen source in case the hydrogen leaks.7.2 Detector Gases, Hydrogen, air, nitrogen, and helium.The minimum purity of the gases used should be 99.9 % molfor the hydrogen, nitrogen, and helium. The air should behydrocarbon-free grade with a minimum purity of 99.0 % mol.Gas
23、 purifiers are recommended for the detector gases.(WarningHydrogen, extremely flammable gas under highpressure.) (WarningAir and helium, compressed gases un-der high pressure.)7.3 Blank of Solvent, n-Hexane with a minimum purity of99.0 %.7.4 Validation Mixture for Apparatus Performance Checks:7.4.1
24、Solvent, n-Octane with a minimum purity of 99.0 %.7.4.2 Standards, n-decane, n-dodecane, n-tetradecane,n-hexadecane with a minimum purity of 99.0 %.8. Sampling8.1 See Practice D4057 for general sampling. Transfer analiquot of synthesized iso-paraffins (SIP) fuel sample into aseptum vial and seal. Ob
25、tain the test sample for analysisdirectly from the sealed septum vial, for either manual orautomatic syringe injection.9. Preparation of Apparatus9.1 Install and condition column in accordance with manu-facturers or suppliers instructions. After conditioning, attachcolumn outlet to flame ionization
26、detector inlet and check forleaks throughout the system. When leaks are found, tighten orreplace fittings before proceeding.9.1.1 When using hydrogen as carrier gas, column condi-tioning shall be performed after connecting the column to thedetector.9.2 Adjust the operating conditions of the gas chro
27、mato-graph (Table 1) and allow the system to equilibrate.9.3 Performance ChecksThe apparatus shall be checkedin regular intervals to make sure that it is in perfect workingcondition. Performance checks are realized by analyzing acalibration mixture in the analytical conditions defined in Table1.9.3.
28、1 Linearity VerificationVerify linearity by analyzing aseries of diluted standards or equivalent spread across thefarnesane content range of the method in order to have at theminimums 15 degrees of freedom. Standard deviation of theresiduals shall be less than 0.5 % which corresponds to a 95 %confid
29、ence interval of 1 %. AnnexA1 gives an example of howlinearity may be confirmed.9.3.2 Calibration Mixture PreparationWeigh the sameamount of n-decane, n-dodecane, n-tetradecane, andn-hexadecane. Dilute the mixture in n-octane in order to obtaina concentration of 2 % mass of each component. See Pract
30、iceD4307.9.3.3 Column EffciencyCalculate the number of theoreti-cal plates on n-tetradecane peak using Eq 1:n 5 5.545Rt W0.5!2(1)TABLE 1 Typical Operating ConditionsColumn Temperature ProgramColumn length 30 mColumn inner diameter 0.25 mmFilm thickness 0.25 mInitial temperature 50 CInitial hold time
31、 0 minProgram rate 3 C minFinal temperature 270 CFinal hold time 20 minInjectorTemperature 300 CSplit ratio 100:1Sample size 1.0 LDetectorType Flame ionizationTemperature 300 CFuel gas Hydrogen (40 mL/min)Oxidizing gas Air (400 mL/min)Make-up gases Helium (45 mL/min) orNitrogen (45 mL/min)Carrier Ga
32、sType Helium or HydrogenFlow rate 1 mL/min (Constant)D7974 152where:n = the number of theoretical plates,Rt = the retention time of n-tetradecane, andW0.5= the peak width at half maximun of n-tetradecane,expressed in the same unit as the retention time.9.3.3.1 The determined Number of theoretical pl
33、ates shallbe 500 000.9.3.4 Apparatus Performance EvaluationPercent mass ofeach component of the calibration mixture is determined frompeak area percentages. Relative error percentage is determinedfrom the known concentrations of the mixture using Eq 2:percent relative error=100?calculated concentrat
34、ion 2 known concentration?!known concentration(2)9.3.4.1 Relative error shall be 5%.9.3.5 Minimum Detectable Level (MDL)Minimum detect-able level is determined by injecting the validation mixturepreparation diluted in n-octane in order to obtain a concentra-tion of 10 mg/kg of each component. The si
35、gnal/noise ratio ofeach component shall be higher than 3. (S/N ratio = S (signalpeak height)/N (noise in peak to peak).10. Gas Chromatographic Analysis Procedure10.1 Set the instrument operating variables. See Table 1 fortypical operating conditions.10.2 Inject 1.0 L of sample into the injection por
36、t and startthe analysis. Obtain a chromatogram and peak integrationreport. Sample chromatograms are shown in Figs. 1-6.10.3 A blank of solvent (for example n-hexane) shall beinjected in between samples to remove memory effects.11. Identification11.1 Before execution of the final calculations, check
37、thechromatogram for correct peak identification by comparisonwith those reported in Table 2 (see also Figs. 1-6, the referencechromatogram associated to those data).12. Calculation12.1 Determine the relative mass percent of the individualcomponents by using the following Eq 3:RMi5AiAt3100 (3)where:R
38、Mi= relative mass percentof the individual components,Ai= area of the individual peak, andAt= total area of all detected peaks.NOTE 1There is no use of specific mass relative response factors thatdepend on the chemical nature or the molecular weight of the identifieddetected components.NOTE 2The lar
39、ge farnesane component being included in the calcu-lation and its response linearity has been verified within the scope of themethod to ensure that there is no column and/or detector overload whichwould lead to its purity underestimation. The results obtained are given inAnnex A1.12.2 Determine the
40、relative mass percent of saturated hy-drocarbon group by summing the corresponding individualcomponents determined as in 12.1, respecting the groupassignment from Table 2.FIG. 1 Chromatogram of a Reference Distillated FarnesaneD7974 15313. Report13.1 Report the purity of farnesane, hexahydrofarnesol
41、, andsum of the saturated hydrocarbons(paraffins+naphthenes+saturated dimers) to the nearest 0.01 %mass, and reference this test method.14. Precision and Bias14.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of gas chromatographictest results from a single
42、 laboratory as follows:14.1.1 RepeatabilityThe difference between successiveresults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialswouldnt, in the long run, in the normal and correct operationof the test method exceed the following
43、 values only in one casein twenty.ComponentsRepeatability, r(Mass percent)Farnesane 0.06Saturated hydrocarbons 0.07Hexahydrofarnesol 0.02NOTE 3Repeatability (95 % probability) has been calculated from 11injections over a period of 2 weeks of a reference distilled farnesanesample.14.1.2 Reproducibili
44、tyReproducibility was not deter-mined for this test method at this time.14.1.3 BiasBias was not determined for this test methodat this time.15. Keywords15.1 farnesane; gas chromatography; hexahydrofarnesol; jetfuel grade; saturated hydrocarbons; synthesized iso-paraffins(SIP) fuelA Light compounds F
45、arnesane regionB Farnesane regionC Hexahydrofarnesol regionD Farnesane dimers regionFIG. 2 Chromatogram Identification RegionsD7974 1541C10Paraffine (C10H22)FIG. 3 Zoom Chromatogram of Region A (0 min to 26 min)D7974 1551 Farnesane (C15H32)2C15Olefins (C15H30)3C15Naphthenes (C15H28)4C15Naphthene (C1
46、5H30)5C15Olefins (C15H26)6C15Naphthene (C15H30)7C15Olefins (C15H26)8 Farnesene (C15H24)9C15Olefins (C15H26)10 C16Paraffin (C16H34)FIG. 4 Zoom Chromatogram of Region B (26.5 min to 31.2 min)D7974 1561 Oxygenated compound (C15H30O)2 Oxygenated compound (C15H30O)3 Hexahydrofarnesol (C15H32O)FIG. 5 Zoom
47、 Chromatogram of Region C (30.5 min to 41.5 min)D7974 1571 Unidentified compounds2C30Saturated Dimers (C30H60)FIG. 6 Zoom Chromatogram of Region D (41 min to 73 min)TABLE 2 List of Compounds in Distilled Farnesane and their Retention Times (Rt)Components Rt (min)SaturatedHydrocarbonsLight compounds
48、unidentified Farnesane 27.6C10Paraffin (C10H22) 8.1 xFarnesane (C15H32)A27.6 xC15Olefins (C15H30) from 27.7 to 28.7C15Naphthenes (C15H28) from 28.7 to 29.1C15Naphthene (C15H30) 29.2 xC15Olefins (C15H26) from 29.3 to 29.5C15Naphthene (C15H30) 29.6 xC15Olefins (C15H26) from 29.7 to 29.8Farnesene (C15H
49、24)B29.9C15Olefins (C15H26) from30to30.35C16Paraffin (C16H34) 31.4 xOxygenated compound C15H30O (1) 34.6Oxygenated compound C15H30O (2) 35.4Hexahydrofarnesol (C15H32O)C37.0Unidentified compound 51.4C30Saturated Dimers (C30H60) from 62.5 to 72.5 xSum of the other unidentified compoundsAFarnesane is an iso-paraffin with chemical formula: C15H32, chemical name: 2,6,10-trimethyldodecane and CAS Registry Number: 3891-98-3.BFarnesene is a branched alkene with chemical formula: C15H24, chemical name: (6E)-7,11-dimethyl-3-methylene-1,6,
