1、Designation: D4815 15aD4815 15bStandard Test Method forDetermination of MTBE, ETBE, TAME, DIPE, tertiary-AmylAlcohol and C1 to C4 Alcohols in Gasoline by GasChromatography1This standard is issued under the fixed designation D4815; the number immediately following the designation indicates the year o
2、foriginal 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.This standard has been approved for use by agencies of the U.S. Depart
3、ment of Defense.1. Scope*1.1 This test method covers the determination of ethers and alcohols in gasolines by gas chromatography. Specific compoundsdetermined are methyl tert-butylether (MTBE), ethyl tert-butylether (ETBE), tert-amylmethylether (TAME), diisopropylether(DIPE), methanol, ethanol, isop
4、ropanol, n-propanol, isobutanol, tert-butanol, sec -butanol, n-butanol, and tert-pentanol (tert-amylalcohol).1.2 Individual ethers are determined from 0.20 mass % to 20.0 mass %. Individual alcohols are determined from 0.20 mass %to 12.0 mass %. Equations used to convert to mass % oxygen and to volu
5、me % of individual compounds are provided. Atconcentrations 10 volume % olefins, the interference may be 0.20 mass %. Annex A1 gives a chromatogram showing theinterference observed with a gasoline containing 10 volume % olefins.1.3 This test method includes a relative bias correlation for ethanol in
6、 spark-ignition engine fuels for the U.S. EPA regulationsreporting based on Practice D6708 accuracy assessment between Test Method D4815 and Test Method D5599 as a possible TestMethod D4815 alternative to Test Method D5599. The Practice D6708 derived correlation equation is only applicable for ethan
7、olin fuels in the concentration range from 2.28 % to 14.42 % by mass as measured by Test Method D4815. The applicable TestMethod D5599 range for ethanol is from 2.16 % to14.39 % by mass as reported by Test Method D5599.1.4 Alcohol-based fuels, such as M-85 and E-85, MTBE product, ethanol product, an
8、d denatured alcohol, are specificallyexcluded from this test method. The methanol content of M-85 fuel is considered beyond the operating range of the system.1.5 Benzene, while detected, cannot be quantified using this test method and must be analyzed by alternate methodology (seeTest Method D3606).
9、1.6 The values stated in SI units are to be regarded as standard.Alternate units, in common usage, are also provided to increaseclarity and aid the users of this test method.1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsib
10、ilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1298 Test Method for Density, Relative Density, or API Gravity of Crude Petroleum and Liquid Petrol
11、eum Products byHydrometer MethodD1744 Test Method for Water in Liquid Petroleum Products by Karl Fischer Reagent31 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.04.0L on Gas Chro
12、matography Methods.Current edition approved April 1, 2015Dec. 1, 2015. Published May 2015December 2015. Originally approved in 1989. Last previous edition approved in 2015 asD4815 15.D4815 15a. DOI: 10.1520/D4815-15A.10.1520/D4815-15B.2 For referencedASTM standards, visit theASTM website, www.astm.o
13、rg, 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.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what chang
14、es have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends 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 offici
15、al document.*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 States1D3606 Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chr
16、omatog-raphyD4052 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use as Analytical StandardsD4420 Test Method for Determination of
17、Aromatics in Finished Gasoline by Gas Chromatography (Withdrawn 2004)3D5599 Test Method for Determination of Oxygenates in Gasoline by Gas Chromatography and Oxygen Selective FlameIonization DetectionD6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Met
18、hods that Purportto Measure the Same Property of a Material3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 low volume connectora special union for connecting two lengths of tubing 1.6 mm inside diameter and smaller.Sometimes this is referred to as zero dead volume union.3.1.2
19、oxygenateany oxygen-containing organic compound that can be used as a fuel or fuel supplement, for example, variousalcohols and ethers.3.1.3 split ratioin capillary gas chromatography, the ratio of the total flow of carrier gas to the sample inlet versus the flowof the carrier gas to the capillary c
20、olumn, expressed bysplit ratio5S1C!/C (1)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 ETBEethyl tert-butylether.3.2.3 MTBEmethyl tert-butylether.3.2.4 TAMEtert-amyl methylether.3.2.
21、5 TCEP1,2,3-tris-2-cyanoethoxypropanea gas chromatographic liquid phase.3.2.6 WCOTa type of capillary gas chromatographic column prepared by coating the inside of the capillary with a thin filmof stationary phase.4. Summary of Test Method4.1 An appropriate internal standard, such as 1,2-dimethoxyeth
22、ane (ethylene glycol dimethyl ether), is added to the sample,which is then introduced into a gas chromatograph equipped with two columns and a column switching valve. The sample firstpasses onto a polar TCEPcolumn, which elutes lighter hydrocarbons to vent and retains the oxygenated and heavier hydr
23、ocarbons.4.2 After methylcyclopentane, but before DIPE and MTBE elute from the polar column, the valve is switched to backflush theoxygenates onto a WCOT nonpolar column. The alcohols and ethers elute from the nonpolar column in boiling point order, beforeelution of any major hydrocarbon constituent
24、s.4.3 After benzene and TAME elute from the nonpolar column, the column switching valve is switched back to its originalposition to backflush the heavy hydrocarbons.4.4 The eluted components are detected by a flame ionization or thermal conductivity detector. The detector response,proportional to th
25、e component concentration, is recorded; the peak areas are measured; and the concentration of each componentis calculated with reference to the internal standard.5. Significance and Use5.1 Ethers, alcohols, and other oxygenates can be added to gasoline to increase octane number and to reduce emissio
26、ns. Typeand concentration of various oxygenates are specified and regulated to ensure acceptable commercial gasoline quality. Drivability,vapor pressure, phase separation, exhaust, and evaporative emissions are some of the concerns associated with oxygenated fuels.3 The last approved version of this
27、 historical standard is referenced on www.astm.org.D4815 15b25.2 This test method is applicable to both quality control in the production of gasoline and for the determination of deliberateor extraneous oxygenate additions or contamination.6. Apparatus6.1 ChromatographWhile any gas chromatographic s
28、ystem, which is capable of adequately resolving the individual ethersand alcohols that are presented in Table 1, can be used for these analyses, a gas chromatographic instrument, which can be operatedat the conditions given in Table 2 and has a column switching and backflushing system equivalent to
29、Fig. 1, has been foundacceptable. Carrier gas flow controllers shall be capable of precise control where the required flow rates are low (see Table 2).Pressure control devices and gages shall be capable of precise control for the typical pressures required.6.1.1 DetectorA thermal conductivity detect
30、or or flame ionization detector can be used. The system shall have sufficientsensitivity and stability to obtain a recorder deflection of at least 2 mm at a signal-to-noise ratio of at least 5 to 1 for 0.005 volume% concentration of an oxygenate.6.1.2 Switching and Backflushing ValveA valve, to be l
31、ocated within the gas chromatographic column oven, capable ofperforming the functions described in Section 11 and illustrated in Fig. 1. The valve shall be of low volume design and notcontribute significantly to chromatographic deterioration.6.1.2.1 Valco Model No. A 4C10WP, 1.6 mm (116 in.) fitting
32、s. This particular valve was used in the majority of the analyses usedfor 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 mm insidediameter and smaller.6.1.2.3 Some gas chromatographs are equipped with an a
33、uxiliary oven, which can be used to contain the valve and polarcolumn. In such a configuration, the nonpolar column is located in the main oven and the temperature can be adjusted for optimumoxygenates resolution.6.1.3 An automatic valve switching device must be used to ensure repeatable switching t
34、imes. Such a device should besynchronized with injection and data collection times.TABLE 1 Pertinent Physical Constants and RetentionCharacteristics for TCEP/WCOT Column Set Conditionsas in Table 2Component RetentionTime, Min.Relative RetentionTime MolecularMassRelativeDensity at15.56/15.5 6C(MTBE =
35、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 60.1 0.8080MTBE 5.04 1.00 0.74 88.2 0.7460sec-Butanol 5.36 1.06 0.79 74.1 0.8114D
36、IPE 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 0.8137TAME 8.17 1.62 1.20 102.2 0.7758TABLE 2 Chromatographic Operation Conditio
37、nsTemperatures Flows, mL/min Carrier Gas: HeliumColumn Oven 60 to injector 75 Sample size, LA 1.03.0Injector, 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 minA Sample size must be a
38、djusted so that alcohols in the range of 0.1 mass % to12.0 mass % and ethers in the range of 0.1 mass % to 20.0 mass % are elutedfrom the column and measured linearly at the detector.Asample size of 1.0 Lhasbeen introduced in most cases.D4815 15b36.1.4 Injection SystemThe chromatograph should be equ
39、ipped with a splitting-type inlet device if capillary columns or flameionization detection are used. Split injection is necessary to maintain the actual chromatographed sample size within the limits ofcolumn and detector optimum efficiency and linearity.6.1.4.1 Some gas chromatographs are equipped w
40、ith on-column injectors and autosamplers, which can inject small samplessizes. Such injection systems can be used provided that sample size is within the limit of the column and detectors optimumefficiency and linearity.6.1.4.2 Microlitre syringes, automatic syringe injectors, and liquid sampling va
41、lves have been used successfully for introducingrepresentative samples into the gas chromatographic inlet.6.2 Data Presentation or Calculation, or Both:6.2.1 RecorderA recording potentiometer or equivalent with a full-scale deflection of 5 mV or less can be used to monitordetector signal. Full-scale
42、 response time should be 1 s or less with sufficient sensitivity and stability to meet the requirements of6.1.1.6.2.2 Integrator or ComputerMeans shall be provided for determining the detector response. Peak heights or areas can bemeasured by computer, electronic integration, or manual techniques.6.
43、3 Columns, Two as Follows:6.3.1 Polar ColumnThis column performs a preseparation of the oxygenates from volatile hydrocarbons in the same boilingpoint range. The oxygenates and remaining hydrocarbons are backflushed onto the nonpolar column in 6.3.2. Any column withequivalent or better chromatograph
44、ic efficiency and selectivity to that described in 6.3.1.1 can be used. The column shall performat the same temperature as required for the column in 6.3.2, except if located in a separate auxiliary oven as in 6.1.2.3.6.3.1.1 TCEP Micro-Packed Column, 560 mm (22 in.) by 1.6 mm (116 in.) outside diam
45、eter by 0.76 mm (0.030 in.) insidediameter stainless steel tube packed with 0.14 g to 0.15 g of 20 % (mass/mass) TCEP on 80/100 mesh Chromosorb P(AW). Thiscolumn was used in the cooperative study to provide the precision and bias data referred to in Section 15.6.3.2 Nonpolar (Analytical) ColumnAny c
46、olumn with equivalent or better chromatographic efficiency and selectivity to thatdescribed 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 silica WCOTcolumn with a 2.6 m film thickness of cross-l
47、inked methyl siloxane. This column was used in the cooperative study to providethe precision and bias data referred to in Section 15.NOTE 1Detector B is optional and used to simplify setting cut times.FIG. 1 Analysis of Oxygenates in Gasoline Schematic of Chromatographic SystemD4815 15b47. Reagents
48、and Materials7.1 Carrier GasCarrier gas appropriate to the type of detector used. Helium has been used successfully. The minimum purityof the carrier gas used must be 99.95 mol %.7.2 Standards for Calibration and IdentificationStandards of all components to be analyzed and the internal standard arer
49、equired for establishing identification by retention time as well as calibration for quantitative measurements. These materials shallbe of known purity and free of the other components to be analyzed. (WarningThese materials are flammable and can beharmful or fatal if ingested or inhaled.)7.3 Methylene Chloride, used for column preparation, reagent grade, free of nonvolatile residue. (WarningHarmful ifinhaled. High concentrations may cause unconsciousness or death.)8. Preparation of Column Packings8.1 TCEP Column Packing:8.1.1 Any sa
