1、Designation: D4815 15Standard Test Method forDetermination of MTBE, ETBE, TAME, DIPE, tertiary-AmylAlcohol and C1to C4Alcohols in Gasoline by GasChromatography1This standard is issued under the fixed designation D4815; the number immediately following the designation indicates the year oforiginal ad
2、option 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.This standard has been approved for use by agencies of the U.S. Department of Defe
3、nse.1. Scope*1.1 This test method covers the determination of ethers andalcohols in gasolines by gas chromatography. Specific com-pounds determined are methyl tert-butylether (MTBE), ethyltert-butylether (ETBE), tert-amylmethylether (TAME), diiso-propylether (DIPE), methanol, ethanol, isopropanol,n-
4、propanol, isobutanol, tert-butanol, sec -butanol, n-butanol,and tert-pentanol (tert-amylalcohol).1.2 Individual ethers are determined from 0.20 to 20.0mass %. Individual alcohols are determined from 0.20 to 12.0mass %. Equations used to convert to mass % oxygen and tovolume % of individual compounds
5、 are provided. At concen-trations 10 volume % olefins, the interference may be0.20 mass %. Annex A1 gives a chromatogram showing theinterference observed with a gasoline containing 10 volume %olefins.1.3 Alcohol-based fuels, such as M-85 and E-85, MTBEproduct, ethanol product, and denatured alcohol,
6、 are specifi-cally excluded from this test method. The methanol content ofM-85 fuel is considered beyond the operating range of thesystem.1.4 Benzene, while detected, cannot be quantified using thistest method and must be analyzed by alternate methodology(see Test Method D3606).1.5 The values stated
7、 in SI units are to be regarded asstandard. Alternate units, in common usage, are also providedto increase clarity and aid the users of this test method.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 th
8、is 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:2D1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hyd
9、rometer MethodD1744 Test Method for Water in Liquid Petroleum Productsby Karl Fischer Reagent3D3606 Test Method for Determination of Benzene andToluene in Finished Motor and Aviation Gasoline by GasChromatographyD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital De
10、nsity MeterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4420 Test Method for Determination of Aromatics inFinished Gasoline by Gas Chromatography (Withdrawn2004)33. Terminology3.1 Definitions of Te
11、rms Specific to This Standard:3.1.1 low volume connectora special union for connectingtwo lengths of tubing 1.6-mm inside diameter and smaller.Sometimes this is referred to as zero dead volume union.3.1.2 oxygenateany oxygen-containing organic compoundthat can be used as a fuel or fuel supplement, f
12、or example,various alcohols and ethers.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Feb. 1, 2015. Published March 20
13、15. Originallyapproved in 1989. Last previous edition approved in 2013 as D4815 13. DOI:10.1520/D4815-15.2For 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 to the standar
14、ds Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary 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
15、States13.1.3 split ratioin capillary gas chromatography, the ratioof the total flow of carrier gas to the sample inlet versus theflow of the carrier gas to the capillary column, expressed bysplit ratio 5 S1C!/C (1)where:S = flow rate at the splitter vent, andC = flow rate at the column outlet.3.1.4
16、tert-amyl alcoholtert -pentanol.3.2 Acronyms:3.2.1 DIPEdiisopropylether.3.2.2 ETBEethyl tert-butylether.3.2.3 MTBEmethyl tert-butylether.3.2.4 TAMEtert-amyl methylether.3.2.5 TCEP1,2,3-tris-2-cyanoethoxypropanea gaschromatographic liquid phase.3.2.6 WCOTa type of capillary gas chromatographic col-um
17、n prepared by coating the inside of the capillary with a thinfilm of stationary phase.4. Summary of Test Method4.1 An appropriate internal standard, such as 1,2-dimethoxyethane (ethylene glycol dimethyl ether), is added tothe sample, which is then introduced into a gas chromatographequipped with two
18、 columns and a column switching valve. Thesample first passes onto a polar TCEP column, which eluteslighter hydrocarbons to vent and retains the oxygenated andheavier hydrocarbons.4.2 After methylcyclopentane, but before DIPE and MTBEelute from the polar column, the valve is switched to backflushthe
19、 oxygenates onto a WCOT nonpolar column. The alcoholsand ethers elute from the nonpolar column in boiling pointorder, before elution of any major hydrocarbon constituents.4.3 After benzene and TAME elute from the nonpolarcolumn, the column switching valve is switched back to itsoriginal position to
20、backflush the heavy hydrocarbons.4.4 The eluted components are detected by a flame ioniza-tion or thermal conductivity detector. The detector response,proportional to the component concentration, is recorded; thepeak areas are measured; and the concentration of eachcomponent is calculated with refer
21、ence to the internal standard.5. Significance and Use5.1 Ethers, alcohols, and other oxygenates can be added togasoline to increase octane number and to reduce emissions.Type and concentration of various oxygenates are specified andregulated to ensure acceptable commercial gasoline quality.Drivabili
22、ty, vapor pressure, phase separation, exhaust, andevaporative emissions are some of the concerns associated withoxygenated fuels.5.2 This test method is applicable to both quality control inthe production of gasoline and for the determination ofdeliberate or extraneous oxygenate additions or contami
23、nation.6. Apparatus6.1 ChromatographWhile any gas chromatographicsystem, which is capable of adequately resolving the individualethers and alcohols that are presented in Table 1, can be usedfor these analyses, a gas chromatographic instrument, whichcan be operated at the conditions given in Table 2
24、and has acolumn switching and backflushing system equivalent to Fig.1, has been found acceptable. Carrier gas flow controllers shallbe capable of precise control where the required flow rates arelow (see Table 2). Pressure control devices and gages shall becapable of precise control for the typical
25、pressures required.6.1.1 DetectorA thermal conductivity detector or flameionization detector can be used. The system shall have suffi-cient sensitivity and stability to obtain a recorder deflection ofat least 2 mm at a signal-to-noise ratio of at least 5 to 1 for0.005 volume % concentration of an ox
26、ygenate.6.1.2 Switching and Backflushing ValveA valve, to belocated within the gas chromatographic column oven, capableof performing the functions described in Section 11 andillustrated in Fig. 1. The valve shall be of low volume designand not contribute significantly to chromatographic deteriora-ti
27、on.6.1.2.1 Valco Model No. A 4C10WP, 1.6-mm (116-in.) fit-tings. This particular valve was used in the majority of theanalyses used for the development of Section 15.TABLE 1 Pertinent Physical Constants and RetentionCharacteristics for TCEP/WCOT Column Set Conditionsas in Table 2ComponentRetentionTi
28、me, Min.Relative RetentionTimeMolecularMassRelativeDensity at15.56/15.56C(MTBE =1.00)(DME =1.00)Water 2.90 0.58 0.43 18.0 1.000Methanol 3.15 0.63 0.46 32.0 0.7963Ethanol 3.48 0.69 0.51 46.1 0.7939Isopropanol 3.83 0.76 0.56 60.1 0.7899tert-Butanol 4.15 0.82 0.61 74.1 0.7922n-Propanol 4.56 0.90 0.67 6
29、0.1 0.8080MTBE 5.04 1.00 0.74 88.2 0.7460sec-Butanol 5.36 1.06 0.79 74.1 0.8114DIPE 5.76 1.14 0.85 102.2 0.7282Isobutanol 6.00 1.19 0.88 74.1 0.8058ETBE 6.20 1.23 0.91 102.2 0.7452tert-Pentanol 6.43 1.28 0.95 88.1 0.81701,2-Dimethoxyethane(DME)6.80 1.35 1.00 90.1 0.8720n-Butanol 7.04 1.40 1.04 74.1
30、0.8137TAME 8.17 1.62 1.20 102.2 0.7758TABLE 2 Chromatographic Operation ConditionsTemperatures Flows, mL/min Carrier Gas: HeliumColumn Oven 60 to injector 75 Sample size, LA1.03.0Injector, C 200 Column 5 Split ratio 15:1DetectorTCD, C 200 Auxiliary 3 Backflush, min 0.20.3FID, C 250 Makeup 18 Valve r
31、eset time 810 minValve C 60 Total Analysis time 1820 minASample size must be adjusted so that alcohols in the range of 0.1 to 12.0 mass% and ethers in the range of 0.1 to 20.0 mass % are eluted from the column andmeasured linearly at the detector. A sample size of 1.0 L has been introduced inmost ca
32、ses.D4815 1526.1.2.2 Valco Model No. C10W, 0.8-mm (132-in.) fittings.This valve is recommended for use with columns of 0.32-mminside diameter and smaller.6.1.2.3 Some gas chromatographs are equipped with anauxiliary oven, which can be used to contain the valve andpolar column. In such a configuratio
33、n, the nonpolar column islocated in the main oven and the temperature can be adjustedfor optimum oxygenates resolution.6.1.3 An automatic valve switching device must be used toensure repeatable switching times. Such a device should besynchronized with injection and data collection times.6.1.4 Inject
34、ion SystemThe chromatograph should beequipped with a splitting-type inlet device if capillary columnsor flame ionization detection are used. Split injection isnecessary to maintain the actual chromatographed sample sizewithin the limits of column and detector optimum efficiencyand linearity.6.1.4.1
35、Some gas chromatographs are equipped with on-column injectors and autosamplers, which can inject smallsamples sizes. Such injection systems can be used providedthat sample size is within the limit of the column and detectorsoptimum efficiency and linearity.6.1.4.2 Microlitre syringes, automatic syri
36、nge injectors, andliquid sampling valves have been used successfully for intro-ducing representative samples into the gas chromatographicinlet.6.2 Data Presentation or Calculation, or Both:6.2.1 RecorderA recording potentiometer or equivalentwith a full-scale deflection of 5 mV or less can be used t
37、omonitor detector signal. Full-scale response time should be 1 sor less with sufficient sensitivity and stability to meet therequirements of 6.1.1.6.2.2 Integrator or ComputerMeans shall be provided fordetermining the detector response. Peak heights or areas can bemeasured by computer, electronic in
38、tegration, or manual tech-niques.6.3 Columns, Two as Follows:6.3.1 Polar ColumnThis column performs a preseparationof the oxygenates from volatile hydrocarbons in the sameboiling point range. The oxygenates and remaining hydrocar-bons are backflushed onto the nonpolar column in 6.3.2. Anycolumn with
39、 equivalent or better chromatographic efficiencyand selectivity to that described in 6.3.1.1 can be used. Thecolumn shall perform at the same temperature as required forthe column in 6.3.2, except if located in a separate auxiliaryoven as in 6.1.2.3.6.3.1.1 TCEP Micro-Packed Column, 560 mm (22 in.)
40、by1.6-mm (116-in.) outside diameter by 0.76-mm (0.030-in.)inside diameter stainless steel tube packed with 0.14 to 0.15 gof 20 % (mass/mass) TCEP on 80/100 mesh ChromosorbP(AW). This column was used in the cooperative study toprovide the precision and bias data referred to in Section 15.6.3.2 Nonpol
41、ar (Analytical) ColumnAny column withequivalent or better chromatographic efficiency and selectivityto that described in 6.3.2.1 and illustrated in Fig. 2 can be used.6.3.2.1 WCOT Methyl Silicone Column, 30-m (1181-in.)long by 0.53-mm (0.021-in.) inside diameter fused silicaWCOT column with a 2.6-m
42、film thickness of cross-linkedmethyl siloxane. This column was used in the cooperativestudy to provide the precision and bias data referred to inSection 15.NOTE 1Detector B is optional and used to simplify setting cut times.FIG. 1 Analysis of Oxygenates in Gasoline Schematic of Chromatographic Syste
43、mD4815 1537. Reagents and Materials7.1 Carrier GasCarrier gas appropriate to the type ofdetector used. Helium has been used successfully. The mini-mum purity of the carrier gas used must be 99.95 mol %.7.2 Standards for Calibration and IdentificationStandardsof all components to be analyzed and the
44、internal standard arerequired for establishing identification by retention time as wellas calibration for quantitative measurements. These materialsshall be of known purity and free of the other components to beanalyzed. (WarningThese materials are flammable and canbe harmful or fatal if ingested or
45、 inhaled.)7.3 Methylene Chloride, used for column preparation, re-agent grade, free of nonvolatile residue. (WarningHarmfulif inhaled. High concentrations may cause unconsciousness ordeath.)8. Preparation of Column Packings8.1 TCEP Column Packing:8.1.1 Any satisfactory method used in the practice of
46、 the artthat will produce a column capable of retaining the C1 to C4alcohols and MTBE, ETBE, DIPE, and TAME from compo-nents of the same boiling point range in a gasoline sample. Thefollowing procedure has been used successfully.8.1.2 Completely dissolve 10 g of TCEP in 100 mL ofmethylene chloride.
47、Next add 40 g of 80/100 mesh Chromo-sorb P(AW) to the TCEPsolution. Quickly transfer this mixtureto a drying dish, in a fume hood, without scraping any of theresidual packing from the sides of the container. Constantly,but gently, stir the packing until all of the solvent hasevaporated. This column
48、packing can be used immediately toprepare the TCEP column.9. Sampling9.1 Every effort should be made to ensure that the sample isrepresentative of the fuel source from which it is taken. Followthe recommendations of Practice D4057, or its equivalent,when obtaining samples from bulk storage or pipeli
49、nes.9.2 Upon receipt in the laboratory, chill the sample in itsoriginal container to 0 to 5C (32 to 40F) before anysubsampling is performed.9.3 If necessary, transfer the chilled sample to a vapor tightcontainer and store at 0 to 5C (32 to 40F) until needed foranalysis.10. Preparation of Micro-Packed TCEP Column10.1 Wash a straight 560-mm length of 1.6-mm outsidediameter (0.76-mm inside diameter) stainless steel tubing withmethanol and dry with compressed nitrogen.10.2 Insert six to twelve strands of silvered wire, a smallmesh screen,
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