1、Designation: D6729 04 (Reapproved 2009)D6729 14Standard Test Method forDetermination of Individual Components in Spark IgnitionEngine Fuels by 100 Metre Capillary High Resolution GasChromatography1This standard is issued under the fixed designation D6729; the number immediately following the designa
2、tion 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 This test method covers th
3、e determination of individual hydrocarbon components of spark-ignition engine fuels and theirmixtures containing oxygenate blends (MTBE, ETBE, ethanol, and so forth) with boiling ranges up to 225C.225 C. Other lightliquid hydrocarbon mixtures typically encountered in petroleum refining operations, s
4、uch as blending stocks (naphthas, reformates,alkylates, and so forth) may also be analyzed; however, statistical data was obtained only with blended spark-ignition engine fuels.1.2 Based on the cooperative study results, individual component concentrations and precision are determined in the range o
5、f0.01 0.01 % mass to approximately 30 mass %.% mass. The procedure may be applicable to higher and lower concentrations forthe individual components; however, the user must verify the accuracy if the procedure is used for components with concentrationsoutside the specified ranges.1.3 The test method
6、 also determines methanol, ethanol, t-butanol, methyl t-butyl ether (MTBE), ethyl t-butyl ether (ETBE),t-amyl methyl ether (TAME) in spark ignition engine fuels in the concentration range of 1 to 30 mass %. 1 % mass to 30 % mass.However, the cooperative study data provided sufficient statistical dat
7、a for MTBE only.1.4 Although a majority of the individual hydrocarbons present are determined, some co-elution of compounds is encountered.If this test method is utilized to estimate bulk hydrocarbon group-type composition (PONA) the user of such data should becautioned that some error will be encou
8、ntered due to co-elution and a lack of identification of all components present. Samplescontaining significant amounts of olefinic or naphthenic (for example, virgin naphthas), or both, constituents above n-octane mayreflect significant errors in PONA type groupings. Based on the gasoline samples in
9、 the interlaboratory cooperative study, thisprocedure is applicable to samples containing less than 2525 % mass % of olefins. However, some interfering coelution with theolefins above C7 is possible, particularly if blending components or their higher boiling cuts such as those derived from fluidcat
10、alytic cracking (FCC) are analyzed, and the total olefin content may not be accurate. Caution should also be exercised whenanalyzing olefin-free samples using this test method as some of the paraffins may be reported as olefins since analysis is basedpurely on retention times of the eluting componen
11、ts.1.4.1 Total olefins in the samples may be obtained or confirmed, or both, if necessary, by Test Method D1319 (volume%)(percent volume) or other test methods, such as those based on multidimensional PONA type of instruments.instruments (TestMethod D6839).1.5 If water is or is suspected of being pr
12、esent, its concentration may be determined, if desired, by the use of Test MethodD1744, or equivalent. Other compounds containing oxygen, sulfur, nitrogen, and so forth, may also be present, and may co-elutewith the hydrocarbons. If determination of these specific compounds is required, it is recomm
13、ended that test methods for thesespecific materials be used, such as Test Methods D4815 and D5599 for oxygenates, and D5623 for sulfur compounds, orequivalent.1.6 Annex A1 of this test method compares results of the test procedure with other test methods for selected components,including olefins, an
14、d several group types for several interlaboratory cooperative study samples. Although benzene, toluene, andseveral oxygenates are determined, when doubtful as to the analytical results of these components, confirmatory analyses can beobtained by using specific test methods.1.7 The values stated in S
15、I units are to be regarded as the standard. The values given in parentheses are provided for informationpurposes only.standard. No other units of measurement are included in this standard.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels,
16、 and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved April 15, 2009Oct. 1, 2014. Published July 2009February 2015. Originally approved in 2001. Last previous edition approved in 20042009 asD6729D6729 04 (2009).041. DOI: 10.1
17、520/D6729-04R09.10.1520/D6729-14.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 to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recomm
18、ends 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 Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700
19、, West Conshohocken, PA 19428-2959. United States11.8 This standard 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 re
20、gulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1319 Test Method for Hydrocarbon Types in Liquid Petroleum Products by Fluorescent Indicator AdsorptionD1744 Test Method for Determination of Water in Liquid Petroleum Products by Karl Fischer ReagentD4815 Test Method for D
21、etermination of MTBE, ETBE, TAME, DIPE, tertiary-Amyl Alcohol and C1 to C4 Alcohols inGasoline by Gas ChromatographyD5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective FlameIonization DetectionD5623 Test Method for Sulfur Compounds in Light Petrol
22、eum Liquids by Gas Chromatography and Sulfur Selective DetectionD6839 Test Method for Hydrocarbon Types, Oxygenated Compounds, and Benzene in Spark Ignition Engine Fuels by GasChromatographyE355 Practice for Gas Chromatography Terms and Relationships3. Terminology3.1 DefinitionsThis test method make
23、s reference to many common gas chromatographic procedures, terms, and relationships.Detailed definitions can be found in Practice E355.4. Summary of Test Method4.1 Representative samples of the petroleum liquid are introduced into a gas chromatograph equipped with an open tubular(capillary) column c
24、oated with the specified stationary phase. Helium carrier gas transports the vaporized sample through thecolumn, in which it is partitioned into individual components which are sensed with a flame ionization detector as they elute fromthe end of the column. The detector signal is recorded digitally
25、by way of an integrator or integrating computer. Each elutingcomponent is identified by comparing its retention time to that established by analyzing reference standards or samples underidentical conditions. The concentration of each component in mass %percent is determined by normalization of the p
26、eak areas aftercorrection of selected components with detector response factors. The unknown components are reported individually and as asummary total.5. Significance and Use5.1 Knowledge of the specified individual component composition (speciation) of gasoline fuels and blending stocks is usefulf
27、or refinery quality control and product specification. Process control and product specification compliance for many individualhydrocarbons may be determined through the use of this test method.6. Apparatus6.1 Gas Chromatograph, a gas chromatograph equipped with cryogenic column oven cooling and cap
28、able of producingrepeatable oven ramps from 00 C to at least 300C300 C is required. The following features are useful during the sampleanalysis phase: electronic flow readout, electronic sample split-ratio readout, and electronic pneumatic control of flow. Thoughtheir use is not required, careful re
29、view of this test method will demonstrate the usefulness of a gas chromatograph equipped withthese features. These features will replace the need to carry out the manual calculations that must be performed as listed in 8.1 and8.2.6.2 Inleta capillary split/splitless inlet system operated in the spli
30、t mode is recommended. It must be operated in its linearrange. Refer to 8.4 to determine the proper split ratio.6.2.1 Carrier Gas Pneumatic Control Constant carrier gas pressure control was used by all cooperative study participants.This may be either direct pressure to the inlet (injector) or by us
31、ing a total flow/back pressure system.6.2.2 Pneumatic Operation of the ChromatographThe use of constant pressure was the mode of operating the gaschromatography used by the participants in the interlaboratory cooperative study. Other carrier gas control methods such asconstant flow (pressure program
32、ming) may be used, but this may change the chromatography elution pattern unless the temperatureprogramming profile is also adjusted to compensate for the flow differences.6.2.3 Temperature ControlThe injector operated in the split mode shall be heated by a separate heating zone and heated totempera
33、tures of 200200 C to 275C.275 C.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.D6729 1426.3 Column, a fused
34、silica capillary column, 100 m in length by 0.25 mm inside diameter, coated with a 0.5 m film of bondeddimethylpolysiloxane. The column must meet the resolution requirements expressed in 8.3. Columns from two differentcommercial sources were used in the interlaboratory cooperative study.6.4 Data Sys
35、tem, a computer based chromatography data system capable of accurately and repeatedly measuring the retentiontime and areas of eluting peaks. The system shall be able to acquire data at a rate of at least 10 Hz. Although it is not mandatory,a data system which calculates column resolution (R) is ext
36、remely useful as it will replace the need to carry out the manualcalculations which must be performed as listed in 8.3.6.4.1 Electronic Integrators, shall be capable of storing up to 400 components in the peak table and shall be able to acquire thedata at 10 Hz or faster speeds. They shall be capabl
37、e of integrating peaks having peak widths at half height which are 1.0s wide.The integrator must be capable of displaying the integration mode of partially resolved peaks. In addition, these integrators shouldbe able to download a commonly readable format of data (that is, ASCII) to a computer in or
38、der to facilitate data processing.6.5 Sample IntroductionSample introduction by way of a valve, automatic injection device, robotic arm or other automaticmeans is highly recommended.An automatic sample introduction device is essential to the reproducibility of the analysis. Manualinjections are not
39、recommended.All of the reproducibility data reported by this test method for the samples analyzed were gatheredusing automatic injection devices.6.6 Flame Ionization Detector (FID) The gas chromatograph should possess a FID having a sensitivity of 0.005 coulombs/gfor n-butane. The linear dynamic ran
40、ge of the detector should be 106 or better. The detector is heated to 300C.300 C.7. Reagents and Materials7.1 Calibrating Standard MixtureAspark ignition engine fuel standard of known composition and concentration by mass canbe used. In order to corroborate the identification of the sample, a typica
41、l chromatogram (Fig. 1) was obtained from referencesample ARC96OX.37.2 Gas Chromatograph GasesAll of the following gases shall have a purity of 99.999 % (V/V) or greater.NOTE 1Warning: Gases are compressed. Some are flammable and all gases are under high pressure.7.2.1 HeliumThe test data was develo
42、ped with helium as the carrier gas. It is possible that other carrier gases may be usedfor this test method. At this time, no data is available from this test method with other carrier gases.7.2.2 Air, Hydrogen and Make-up Gas (Helium or Nitrogen), shall have a purity of 99.999 % (V/V) or greater.8.
43、 Instrument Check Out Prior to Analysis8.1 Setting:8.1.1 Linear Gas VelocityIf the gas chromatograph is equipped with an electronic flow readout device, set the flow to 1.8mL/min. This is achieved by setting the carrier gas flow rate by injection of cm/s methane or natural gas at 35C.35 C. Ensuretha
44、t the retention time is 7.007.00 min 6 0.05 min. This corresponds to a linear velocity of 25 cm/s to 26 cm/s. This is equivalentto retention times of methane at 0C0 C ranging from 6.5 min to 6.8 min.8.1.2 If the gas chromatograph is not equipped with an electronic flow readout device, calculate the
45、linear gas velocity in cm/susing Eq 1.linear gas velocity5V 5 column lengthcm!retention time of methanes! (1)8.1.3 The typical retention times for methane and linear gas velocity for helium are 6.56.5 cms to 6.86.8 cms and 2424 cmsto 2626 cm cm/s, s, respectively.8.2 Setting the Split RatioIf the ga
46、s chromatograph is equipped with an electronic split-ratio readout device, set the split ratioto a sample split of 200:1. If the gas chromatograph is not equipped with an electronic split-ratio readout device, one must firstcalculate column flow rate and then proceed to calculating split ratio using
47、 Eq 2 and 3.column flow rate5F 560 pi r2!LTref! 2Pi 2Po!T!3Pref!Pi22Po2! (2)where:F = flow rate as calculated by using the equation,r = column radius, cm,L = column length, cm,Pi = inlet pressure,Po = outlet pressure,Pref = reference pressure, 1 atm,3 Reference spark ignition sample No. ARC 960X obt
48、ained from the Alberta Research Council, Edmonton, Alberta, Canada. Other samples are available from suppliers.D6729 143FIG. 1 Chromatogram for Reference Spiked GasolineD6729 144T = temperature of the column oven,Tref = temperature at the column outlet, and = linear velocity, cm/s.split ratio5S 5spl
49、it vent flow1FF (3)FIG. 1 Chromatogram for Reference Spiked Gasoline (continued)D6729 145FIG. 1 Chromatogram for Reference Spiked Gasoline (continued)D6729 1468.2.1 The column flow rate is calculated by the use of Eq 2. Use the results obtained from Eq 3 to adjust the split flow untila split flow of approximately 200:1 is achieved.8.3 Evaluation of Column Performance : Performance:8.3.1 Prior to using the column described in Table 1, measure the resolution of the column under the conditions of Table 2.Check that the resolution f
