1、Designation: D4815 09D4815 13Standard 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 ofo
2、riginal 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 Department of
3、 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, isopropanol
4、, n-propanol, isobutanol, tert-butanol, sec -butanol, n-butanol, and tert-pentanol (tert-amylalcohol).1.2 Individual ethers are determined from 0.20 to 20.0 mass %. Individual alcohols are determined from 0.20 to 12.0 mass %.Equations used to convert to mass % oxygen and to volume % of individual co
5、mpounds are provided. At concentrations 10 volume %olefins, the interference may be 0.20 mass %. AnnexA1 gives a chromatogram showing the interference observed with a gasolinecontaining 10 volume % olefins.1.3 Alcohol-based fuels, such as M-85 and E-85, MTBE product, ethanol product, and denatured a
6、lcohol, are specificallyexcluded from this test method. The methanol content of M-85 fuel is considered beyond the operating range of the system.1.4 Benzene, while detected, cannot be quantified using this test method and must be analyzed by alternate methodology (seeTest Method D3606).1.5 The value
7、s 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.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the u
8、ser 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 Petroleum Products
9、byHydrometer MethodD1744 Test Method for Water in Liquid Petroleum Products by Karl Fischer Reagent3D3606 Test Method for Determination of Benzene and Toluene in Finished Motor and Aviation Gasoline by Gas Chromatog-raphyD4052 Test Method for Density, Relative Density, and API Gravity of Liquids by
10、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 Aromatics in Finished Gasoline by Gas Chromatography (Withdrawn 2004)31 This test method is
11、 under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Oct. 1, 2009Oct. 1, 2013. Published November 2009October 2013. Originally approve
12、d in 1989. Last previous edition approved in 20042009as D4815D4815 09.04. DOI: 10.1520/D4815-09.10.1520/D4815-13.2 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
13、standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.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 ve
14、rsion. 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 official document.*A Summary of Changes se
15、ction appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 low volume connectora special union for connecting two lengths of tubing 1
16、.6-mm inside diameter and smaller.Sometimes this is referred to as zero dead volume union.3.1.2 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 to
17、tal flow of carrier gas to the sample inlet versus the flowof the carrier gas to the capillary column, 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
18、 ETBEethyl tert-butylether.3.2.3 MTBEmethyl tert-butylether.3.2.4 TAMEtert-amyl methylether.3.2.5 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 stationa
19、ry phase.4. Summary of Test Method4.1 An appropriate internal standard, such as 1,2-dimethoxyethane (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 T
20、CEPcolumn, which elutes lighter hydrocarbons to vent and retains the oxygenated and heavier hydrocarbons.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 fro
21、m the nonpolar column in boiling point order, beforeelution of any major hydrocarbon constituents.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
22、by a flame ionization or thermal conductivity detector. The detector response,proportional to the 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, alcohol
23、s, and other oxygenates can be added to gasoline to increase octane number and to reduce emissions. Typeand concentration of various oxygenates are specified and regulated to ensure acceptable commercial gasoline quality. Drivability,vapor pressure, phase separation, exhaust, and evaporative emissio
24、ns are some of the concerns associated with oxygenated fuels.5.2 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
25、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
26、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
27、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
28、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.D4815 1326.1.2.1 Valco Model No. A 4C10WP, 1.6-mm (116-in.
29、) fittings.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 w
30、ith an auxiliary 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 swi
31、tching times. Such a device should besynchronized with injection and data collection times.6.1.4 Injection SystemThe chromatograph should be equipped with a splitting-type inlet device if capillary columns or flameionization detection are used. Split injection is necessary to maintain the actual chr
32、omatographed sample size within the limits ofcolumn and detector optimum efficiency and linearity.6.1.4.1 Some gas chromatographs are equipped with on-column injectors and autosamplers, which can inject small samplessizes. Such injection systems can be used provided that sample size is within the li
33、mit of the column and detectors optimumefficiency and linearity.6.1.4.2 Microlitre syringes, automatic syringe injectors, and liquid sampling valves have been used successfully for introducingrepresentative samples into the gas chromatographic inlet.6.2 Data Presentation or Calculation, or Both:6.2.
34、1 RecorderA recording potentiometer or equivalent with a full-scale deflection of 5 mV or less can be used to monitordetector signal. Full-scale 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 p
35、rovided for determining the detector response. Peak heights or areas can bemeasured by computer, electronic integration, or manual techniques.6.3 Columns, Two as Follows:6.3.1 Polar ColumnThis column performs a preseparation of the oxygenates from volatile hydrocarbons in the same boilingpoint range
36、. The oxygenates and remaining hydrocarbons are backflushed onto the nonpolar column in 6.3.2. Any column withTABLE 1 Pertinent Physical Constants and RetentionCharacteristics for TCEP/WCOT Column Set Conditionsas in Table 2Component RetentionTime, Min.Relative RetentionTime MolecularMassRelativeDen
37、sity 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 60.1 0.8080MTBE 5.04 1.00 0.74 88.2 0.7460sec-Butanol 5
38、.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 0.8137TAME 8.17 1.62 1.20 102.2 0.7758TABLE 2 Chromato
39、graphic Operation ConditionsTemperatures 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
40、minA Sample 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 cases.D4815 133equivalent or better chromatographic ef
41、ficiency 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 diameter
42、by 0.76-mm (0.030-in.) insidediameter stainless steel tube packed with 0.14 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 column w
43、ith 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-linked m
44、ethyl 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 1347. Reagents and Mate
45、rials7.1 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 arerequired
46、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 Chlo
47、ride, 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 satisfactory method used in the practice of the art that will produce a
48、 column capable of retaining the C1 to C4alcohols and MTBE, ETBE, DIPE, and TAME from components 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 of methylene chloride. Next add 40 g of 80/100 mes
49、h Chromosorb P(AW)to the TCEP solution. Quickly transfer this mixture to a drying dish, in a fume hood, without scraping any of the residual packingfrom the sides of the container. Constantly, but gently, stir the packing until all of the solvent has evaporated. This column packingcan be used immediately to prepare the TCEP column.9. Sampling9.1 Every effort should be made to ensure that the sample is representative of the fuel source from which it is taken. Followthe recommendations of Practice D4057, or its equivalent, when obtainin
