1、Designation: D5599 00 (Reapproved 2010)Standard Test Method forDetermination of Oxygenates in Gasoline by GasChromatography and Oxygen Selective Flame IonizationDetection1This standard is issued under the fixed designation D5599; the number immediately following the designation indicates the year of
2、original 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 covers a gas chromatographic proce-dure fo
3、r the quantitative determination of organic oxygenatedcompounds in gasoline having a final boiling point not greaterthan 220C and oxygenates having a boiling point limit of130C. It is applicable when oxygenates are present in the 0.1to 20 % by mass range.1.2 This test method is intended to determine
4、 the massconcentration of each oxygenate compound present in a gaso-line. This requires knowledge of the identity of each oxygenatebeing determined (for calibration purposes). However, theoxygen-selective detector used in this test method exhibits aresponse that is proportional to the mass of oxygen
5、.Itis,therefore, possible to determine the mass concentration ofoxygen contributed by any oxygenate compound in the sample,whether or not it is identified. Total oxygen content in agasoline may be determined from the summation of theaccurately determined individual oxygenated compounds. Thesummed ar
6、ea of other, uncalibrated or unknown oxygenatedcompounds present, may be converted to a mass concentrationof oxygen and summed with the oxygen concentration of theknown oxygenated compounds.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in
7、 thisstandard.1.4 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 regulatory limitations prior to use.2
8、. Referenced Documents2.1 ASTM Standards:2D1744 Test Method for Determination of Water in LiquidPetroleum Products by Karl Fischer Reagent3D4175 Terminology Relating to Petroleum, PetroleumProducts, and LubricantsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsE594 Prac
9、tice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE1064 Test Method for Water in Organic Liquids by Cou-lometric Karl Fischer TitrationE1510 Practice for Installing Fused Silica Open TubularCapillary Columns in Gas Chromatographs3. Terminology3.1 Definitions
10、:3.1.1 independent reference standardscalibration samplesof the oxygenates which are purchased or prepared frommaterials independent of the quality control check standardsand used for intralaboratory accuracy.3.1.2 oxygenate, nan oxygen-containing compound, suchas an alcohol or ether, which may be u
11、sed as a fuel or fuelsupplement. D41753.1.3 quality control check standardscalibration samplesof the oxygenates for intralaboratory repeatability.4. Summary of Test Method4.1 An internal standard of a noninterfering oxygenate, forexample, 1,2-dimethoxyethane (ethylene glycol dimethyl1This test metho
12、d is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1994. Last previous edition approved in
13、2005 as D559900(2005).DOI: 10.1520/D5599-00R10.2For 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 to the standards Document Summary page onthe ASTM website.3Withdrawn. Th
14、e last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.ether) is added in quantitative proportion to the gasolinesample. A representative aliquot of the sample
15、 and internalstandard is injected into a gas chromatograph equipped with acapillary column operated to ensure separation of the oxygen-ates. Hydrocarbons and oxygenates are eluted from the col-umn, but only oxygenates are detected with the oxygen-selective flame ionization detector (OFID).Adiscussio
16、n of thisdetector is presented in Section 6.4.2 Calibration mixtures are used for determining the reten-tion times and relative mass response factors of the oxygenatesof interest. Suggested calibrant materials are listed in 8.2.4.3 The peak area of each oxygenate in the gasoline ismeasured relative
17、to the peak area of the internal standard. Aquadratic least-squares fit of the calibrated data of eachoxygenate is applied and the concentration of each oxygenatecalculated.NOTE 1While 1,2-dimethoxyethane has been found to be an appro-priate internal standard, other oxygenates may be used provided t
18、hey arenot present in the sample and do not interfere with any compound ofinterest.5. Significance and Use5.1 In gasoline blending, the determination of organicoxygenated compounds is important. Alcohols, ethers, andother oxygenates are added to gasoline to increase the octanenumber and to reduce ta
19、ilpipe emissions of carbon monoxide.They must be added in the proper concentration and ratios tomeet regulatory limitations and to avoid phase separation andproblems with engine performance or efficiency.5.2 This test method provides sufficient oxygen-to-hydro-carbon selectivity and sensitivity to a
20、llow determination ofoxygenates in gasoline samples without interference from thebulk hydrocarbon matrix.6. Theory of OFID Operation6.1 The detection system selective for organic oxygenconsists of a cracking reactor, hydrogenating reactor (metha-nizer), and a flame ionization detector (FID). The cra
21、ckingreactor, connected immediately after the gas chromatographiccapillary column, consists of a Pt/Rh capillary tube. Carbonmonoxide (CO) is formed from compounds containing oxygenaccording to the following reaction:CxHyOzzCO 1y/2!H21x 2 z!C (1)6.2 An excess layer of carbon is created in the Pt/Rh
22、tube ofthe cracking reactor from the introduction of hydrocarbonsfrom the sample or, if so designed, from a hydrocarbon (forexample, pentane or hexane) doping system, or both. This layerof carbon facilitates the cracking reaction and suppresseshydrocarbon response.6.3 The carbon monoxide formed in t
23、he cracking reactor isconverted to methane in the hydrogenating reactor according tothe following reaction:CO 1 3H2CH41 H2O (2)The CH4is subsequently detected with an FID.6.4 The methanizer consists either of a short porous layeropen tubular (PLOT) glass capillary tube internally coated withaluminum
24、 oxide with adsorbed nickel catalyst or stainless steeltubing containing a nickel-based catalyst. It is installed withinor before the FID and is operated in the range from 350 to450C, depending on the instruments manufacturer.NOTE 2Gasolines with high sulfur content may cause a loss indetector sensi
25、tivity thereby limiting the number of samples that can beanalyzed before the catalyst needs replacement.7. Apparatus7.1 Gas ChromatographAny gas chromatograph can beused having the following performance characteristics:7.1.1 Column Temperature ProgrammerThe chromato-graph must be capable of reproduc
26、ible linear temperatureprogramming over a range sufficient for separation of thecomponents of interest.7.1.2 Sample Introduction SystemAny system capable ofintroducing a representative 0.1 to 1.0-L liquid sample intothe split inlet device of the gas chromatograph. Microlitresyringes, autosamplers, a
27、nd liquid sampling valves have beenused successfully. The split injector should be capable ofaccurate split control in the range from 10:1 to 500:1.7.1.3 Carrier and Detector Gas ControlConstant flowcontrol of carrier and detector gases is critical to optimum andconsistent analytical performance. Co
28、ntrol is best provided bythe use of pressure regulators and fixed flow restrictors. Thegas flow rates are measured by any appropriate means. Thesupply pressure of the gas delivered to the gas chromatographmust be at least 70 kPa (10 psig) greater than the regulated gasat the instrument to compensate
29、 for the system back pressure.In general, a supply pressure of 550 kPa (80 psig) will besatisfactory.7.2 OFID Detector System, consisting of a cracking reactor,methanizer, and FID. A schematic of a typical OFID system isshown in Fig. 1.7.2.1 The detector must meet or exceed the typical specifi-catio
30、ns given in Table 1 of Practice E594 while operating in thenormal FID mode as specified by the manufacturer.7.2.2 In the OFID mode, the detector shall meet or exceedthe following specifications: (a) equal to or greater than 103linearity, (b) less than 100-ppm mass oxygen (1-ng O/s)sensitivity, (c) g
31、reater than 106selectivity for oxygen com-pounds over hydrocarbons, (d) no interference from coelutingcompounds when 0.1 to 1.0-L sample is injected, (e) equimo-lar response for oxygen.7.3 ColumnA 60-m by 0.25-mm inside diameter fusedsilica open tubular column containing a 1.0-m film thicknessof bon
32、ded methyl silicone liquid phase is used. Equivalentcolumns which provide separation of all oxygenates of interestmay be used.7.4 IntegratorUse of an electronic integrating device orcomputer is required. The device and software should have thefollowing capabilities:7.4.1 Graphic presentation of the
33、chromatogram,7.4.2 Digital display of chromatographic peak areas,7.4.3 Identification of peaks by retention time,7.4.4 Calculation and use of response factors, and7.4.5 Internal standard calculation and data presentation.8. Reagents and Materials8.1 Purity of ReagentsReagents grade chemicals shall b
34、eused in all tests. Unless otherwise indicated, it is intended thatD5599 00 (2010)2all reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascerta
35、ined that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.8.2 Calibrant MaterialsThe following compounds maybe used for calibrating the detector: methanol, ethanol,n-propanol, iso-propanol, n-butanol, tert-butanol, sec-butanol,iso-butano
36、l, tert-pentanol, methyl tert-butylether (MTBE),tert-amylmethylether (TAME), ethyl tert-butylether (ETBE),di-iso-propylether (DIPE). (WarningThese materials arevery flammable and may be harmful or fatal when ingested,inhaled, or allowed to be absorbed through the skin.)8.3 Internal StandardUse one o
37、f the compounds listed in8.2 that is not present in the sample. If all of the materials in 8.2are likely to be present in the test sample, use another organicoxygenate of high-grade purity that is separated from all otheroxygenates present (for example, 1,2-dimethoxyethane).8.4 DopantIf the OFID is
38、so designed, reagent-gradepentane is used as a hydrocarbon dopant for the crackingreactor. (WarningPentane is extremely flammable andharmful when inhaled.)8.5 Instrument GasesThe gases supplied to the gas chro-matograph and detector are:8.5.1 Air, zero grade. (WarningCompressed air is a gasunder hig
39、h pressure and supports combustion.)8.5.2 Hydrogen, pure grade, 99.9 mol % minimum purity.(WarningHydrogen is an extremely flammable gas underhigh pressure.)8.5.3 Helium or nitrogen as column carrier gas, 99.995 mol% minimum purity, or a blend of 95 % helium/5 % hydrogen,depending on the instruments
40、 manufacturer. (WarningHelium and nitrogen are compressed gases under high pres-sure.)8.5.4 Additional purification of the carrier, air, and hydro-gen is recommended. Use molecular sieves, Drierite, charcoal,or other suitable agents to remove water, oxygen, and hydro-carbons from the gases.8.6 Sampl
41、e ContainerGlass vials with crimp-on or screw-down sealing caps with self-sealing polytetrafluoroethylene(PTFE)-faced rubber membranes are used to prepare calibra-tion standards and samples for analysis.9. Preparation of Apparatus9.1 Chromatograph and OFIDPlace instrument and de-tector into operatio
42、n in accordance with the manufacturersinstructions. Install the capillary column according to PracticeE1510. Adjust the operating conditions to provide for separa-tion of all oxygenates of interest. Typical conditions used withthe column specified in 7.3 are listed in Table 1.9.2 System PerformanceA
43、t the beginning of each day ofoperation, inject an oxygenate-free gasoline sample into thechromatograph to ensure minimum hydrocarbon response. Ifhydrocarbon response is detected, the OFID is not operatingeffectively and must be optimized according to the manufac-turers instructions before the sampl
44、e can be analyzed.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United
45、 States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Schematic of an OFIDTABLE 1 Typical Operating ConditionsTemperatures, CInjector 250Column 50C (hold 10 min), ramp 8/min to 250CDetector Methanizer 350450Reactor 8501300Flows, mL/minColumn carr
46、ier gas 1Detector gases Air: 300H2:30Auxiliary (for dopant, if available) H2:0.6Sample Size 0.11.0 LASplit Ratio 1001ASample size and split ratio must be adjusted so that the oxygenates in therange from 0.1 to 20.0 mass % are eluted from the column and measured linearlyat the detector. Each laborato
47、ry must establish and monitor the conditions that areneeded to maintain linearity with their individual instruments. Nonlinearity is mostcommonly observed when using an OFID with samples containing high levels ofindividual oxygenates and can be compensated for by either decreasing thesample size, in
48、creasing the split ratio, or diluting the sample with an oxygenate-free gasoline. A sample size of 0.5 L and a split ratio of 100:1 has been usedsuccessfully in most cases.D5599 00 (2010)310. Calibration and Standardization10.1 Retention Time Identification Determine the reten-tion time of each oxyg
49、enate component by injecting smallamounts either separately or in known mixtures. Table 2 givestypical retention times for the oxygenates eluting from a 60-mmethyl silicone column temperature programmed according toconditions given in Table 1. A chromatogram of a blend ofoxygenates is given in Fig. 2.10.2 Preparation of Calibration SamplesThe calibrationsamples are prepared gravimetrically in accordance with Prac-tice D4307 by blending known weights of organic oxygenatecompounds (such as listed in 8.2) with a known weight internalst
