1、Designation: D 4815 04An American National StandardStandard Test Method forDetermination of MTBE, ETBE, TAME, DIPE, tertiary-AmylAlcohol and C1to C4Alcohols in Gasoline by GasChromatography1This standard is issued under the fixed designation D 4815; the number immediately following the designation i
2、ndicates 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.This standard has been approved for use by agencie
3、s of the Department of Defense.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), methan
4、ol, ethanol, isopropanol,n-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
5、 % of individual compounds 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 produ
6、ct, and denatured alcohol, 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 D
7、3606).1.5 The values stated 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 therespo
8、nsibility 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:2D 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude
9、Petroleum and LiquidPetroleum Products by Hydrometer MethodD 1744 Test Method for Water in Liquid Petroleum Prod-ucts by Karl Fischer Reagent3D 3606 Test Method for the Determination of Benzene andToluene in Finished Motor and Aviation Gasoline by GasChromatographyD 4052 Test Method for Density and
10、Relative Density ofLiquids by Digital Density MeterD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD 4420 Test Method for Determination of Aromatics inFinished Gasoline by Gas Chromatography33. Termi
11、nology3.1 Definitions of Terms 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 com-pound that can be used as
12、 a fuel or fuel supplement, forexample, various alcohols and ethers.3.1.3 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 S 1 C!/C (1)1This test method is un
13、der the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04 on Hydrocarbon Analysis.Current edition approved Nov. 1, 2004. Published February 2005. Originallyapproved in 1989. Last previous edition approved in 2003 as D 4815 0
14、3.2For 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.1*A Summary of Changes section appears at the en
15、d of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.where:S = flow rate at the splitter vent, andC = flow rate at the column outlet.3.1.4 tert-amyl alcoholtert-pentanol.3.2 Acronyms:3.2.1 DIPEdiisopropylether.3.2.2 ETBE
16、ethyl 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-umn prepared by coating the inside of the capillary with a thinfilm of stationary ph
17、ase.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 columns and a column switching valve. Thesample first passes onto a polar TCEP co
18、lumn, 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 oxygenates onto a WCOT nonpolar column. The alcoholsand ethers elute from the non
19、polar 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 backflush the heavy hydrocarbons.4.4 The eluted components are detected by a flame
20、 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 reference to the internal standard.5. Significance and Use5.1 Ethers, alcohols, and oth
21、er 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.Drivability, vapor pressure, phase separation, exhaust, andevaporative emissions are some o
22、f 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 contamination.6. Apparatus6.1 ChromatographWhile any gas chromatographic sys-tem, which i
23、s 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 and has acolumn switching and backflushing system equivalent to Fig.1, has been
24、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 pressures required.6.1.1 DetectorA thermal conductivity detector or flameionizat
25、ion 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 oxygenate.6.1.2 Switching and Backflushing ValveA valve, to belocated within the g
26、as 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-tion.6.1.2.1 Valco Model No. A 4C10WP, 1.6-mm (116-in.)fittings. This particular v
27、alve was used in the majority of theanalyses used for the development of Section 15.6.1.2.2 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 c
28、an be used to contain the valve andpolar column. In such a configuration, 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 shou
29、ld besynchronized with injection and data collection times.TABLE 1 Pertinent Physical Constants and RetentionCharacteristics for TCEP/WCOT Column Set Conditionsas in Table 2ComponentRetentionTime, Min.Relative RetentionTimeMolecularMassRelativeDensity at15.56/15.56C(MTBE =1.00)(DME =1.00)Water 2.90
30、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 60.1 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.
31、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 0.8137TAME 8.17 1.62 1.20 102.2 0.7758TABLE 2 Chromatographic Operation ConditionsTemperatures Flows, mL/mi
32、n 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 reset time 810 minValve C 60 Total Analysis time 1820 minASample size must be adjusted so that alcohols in t
33、he 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 cases.D48150426.1.4 Injection SystemThe chromatograph should beequipped with a splitting-type inlet device if
34、 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 Some gas chromatographs are equipped with on-column injectors and autosamplers, whi
35、ch 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 syringe injectors, andliquid sampling valves have been used successfully for intro-duci
36、ng 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 tomonitor detector signal. Full-scale response time should be 1 sor less with suffic
37、ient 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 integration, or manual tech-niques.6.3 Columns, Two as Follows:6.3.1 Polar ColumnThis
38、 column performs a presepara-tion of 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 equivalent or better chromatographic efficiencyand selectivity to that described
39、 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,4560 mm (22 in.) by1.6-mm (116-in.) outside diameter by 0.76-mm (0.030-in.)inside diameter stainle
40、ss 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 Nonpolar (Analytical) ColumnAny column withequivalent or better chromatographic efficie
41、ncy 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 film thickness of cross-linkedmethyl siloxane. This column was used in the cooper
42、ativestudy to provide the precision and bias data referred to inSection 15.7. 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
43、 IdentificationStandards of all components to be analyzed and the internalstandard are required for establishing identification by reten-tion time as well as calibration for quantitative measurements.These materials shall be of known purity and free of the othercomponents to be analyzed. (WarningThe
44、se materials areflammable and can be harmful or fatal if ingested or inhaled.)4The sole source of supply of the micro-packed column known to the committeeat this time is Hewlett Packard Co., Avondale, PA. If you are aware of alternativesuppliers, please provide this information to ASTM International
45、 Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee1, which you may attend.FIG. 1 Analysis of Oxygenates in Gasoline Schematic ofChromatographic SystemD48150437.3 Methylene Chloride, used for column preparation, re-agent grade, free of no
46、nvolatile 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 the artthat will produce a column capable of retaining the C1 to C4alcohols and MTBE, ET
47、BE, 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. Next add 40 g of 80/100 mesh Chro-mosorb P(AW) to the TCEP solution. Quickly transfer thi
48、smixture to a drying dish, in a fume hood, without scraping anyof the residual packing from the sides of the container.Constantly, but gently, stir the packing until all of the solventhas evaporated. This column packing can be used immediatelyto prepare the TCEP column.9. Sampling9.1 Every effort sh
49、ould be made to ensure that the sample isrepresentative of the fuel source from which it is taken. Followthe recommendations of Practice D 4057, or its equivalent,when obtaining samples from bulk storage or pipelines.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 straigh
