1、Designation: D4815 15D4815 15aStandard 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 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.This standard has been approved for use by agencies of the U.S. Departm
3、ent 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, isopr
4、opanol, n-propanol, isobutanol, tert-butanol, sec -butanol, n-butanol, and tert-pentanol (tert-amylalcohol).1.2 Individual ethers are determined from 0.200.20 mass % to 20.0 mass %. Individual alcohols are determined from0.200.20 mass % to 12.0 mass %. Equations used to convert to mass % oxygen and
5、to volume % of individual compounds areprovided. At concentrations 10 volume % olefins, the interference may be 0.20 mass %. Annex A1 gives a chromatogram showingthe interference observed with a gasoline containing 10 volume % olefins.1.3 Alcohol-based fuels, such as M-85 and E-85, MTBE product, eth
6、anol product, and denatured alcohol, are specificallyexcluded from this test method. The methanol content of M-85 fuel is considered beyond the operating range of the system.1.4 Benzene, while detected, cannot be quantified using this test method and must be analyzed by alternate methodology (seeTes
7、t Method D3606).1.5 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.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It
8、is the responsibilityof 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 a
9、nd Liquid Petroleum Products 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, a
10、nd 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 Aromatics in Finished Gasoline by Gas Chromatography (Withdraw
11、n 2004)31 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of SubcommitteeD02.04.0L on Gas Chromatography Methods.Current edition approved Feb. 1, 2015April 1, 2015. Published March 2015May 2015. Origi
12、nally approved in 1989. Last previous edition approved in 20132015 asD4815 13.D4815 15. DOI: 10.1520/D4815-15.10.1520/D4815-15A.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information
13、, refer to the 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
14、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 official document.*A Summar
15、y 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 States13. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 low volume connectora special union for connecting two leng
16、ths of tubing 1.6-mm1.6 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
17、, the ratio of the total 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 DIPEd
18、iisopropylether.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 gas chromatographic liquid phase.3.2.6 WCOTa type of capillary gas chromatographic column prepared by coating the inside of the capillary with a
19、 thin filmof stationary 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 first
20、passes onto a polar TCEPcolumn, 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
21、 and ethers elute from 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 com
22、ponents are detected 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 U
23、se5.1 Ethers, alcohols, 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, an
24、d evaporative emissions 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
25、gas chromatographic system, 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
26、system equivalent to 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 therma
27、l conductivity detector or flame ionization detector can be used. The system shall have sufficientsensitivity and stability to obtain a recorder deflection of at least 2 mm 2 mm at a signal-to-noise ratio of at least 5 to 1 for 0.005volume % concentration of an oxygenate.6.1.2 Switching and Backflus
28、hing ValveA valve, to be located 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 15a26.1.2.1 Valco Model No
29、. A 4C10WP, 1.6-mm1.6 mm (116-in.) in.) fittings. This particular valve was used in the majority of theanalyses used for the development of Section 15.6.1.2.2 Valco Model No. C10W, 0.8-mm0.8 mm (132-in.) in.) fittings. This valve is recommended for use with columns of0.32-mm0.32 mm inside diameter a
30、nd smaller.6.1.2.3 Some gas chromatographs are equipped with 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 val
31、ve switching device must be used to ensure repeatable switching 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
32、. 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 with on-column injectors and autosamplers, which can inject small samplessizes. Such injection syste
33、ms 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 valves have been used successfully for introducingrepresentative samples into the gas chromatographic
34、 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 5 mV or less can be used tomonitor detector signal. Full-scale response time should be 1 s 1 s or less with sufficient sensitivity and stability to meet the
35、requirements of 6.1.1.6.2.2 Integrator or ComputerMeans shall be provided for determining the detector response. Peak heights or areas can bemeasured by computer, electronic integration, or manual techniques.6.3 Columns, Two as Follows:6.3.1 Polar ColumnThis column performs a preseparation of the ox
36、ygenates 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 withTABLE 1 Pertinent Physical Constants and RetentionCharacteristics for TCEP/WCOT Column Set Conditionsas in Table 2Component
37、RetentionTime, Min.Relative RetentionTime MolecularMassRelativeDensity at15.56/15.56C15.56/15.5 6C(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-
38、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 0.7282Isobutanol 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-But
39、anol 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/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 0.20.3FI
40、D, C 250 Makeup 18 Valve reset time 810 minValve C 60 Total Analysis time 1820 minA Sample size must be adjusted so that alcohols in the range of 0.1 to 12.0 mass0.1 mass % to 12.0 mass % and ethers in the range of 0.1 0.1 mass % to 20.0mass % are eluted from the column and measured linearly at the
41、detector. Asample size of 1.0 L 1.0 L has been introduced in most cases.D4815 15a3equivalent or better chromatographic 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 sepa
42、rate auxiliary oven as in 6.1.2.3.6.3.1.1 TCEP Micro-Packed Column, 560 mm (22 in.) by 1.6-mm560 mm (22 in.) by 1.6 mm (116-in.) in.) outside diameter by0.76-mm (0.030-in.)0.76 mm (0.030 in.) inside diameter stainless steel tube packed with 0.140.14 g to 0.15 g 0.15 g of 20 %(mass/mass) TCEP on 80/1
43、00 mesh Chromosorb P(AW). This column was used in the cooperative study to provide the precisionand bias data referred to in Section 15.6.3.2 Nonpolar (Analytical) ColumnAny column with equivalent or better chromatographic efficiency and selectivity to thatdescribed in 6.3.2.1 and illustrated in Fig
44、. 2 can be used.6.3.2.1 WCOT Methyl Silicone Column, 30-m (1181-in.)30 m (1181 in.) long by 0.53-mm (0.021-in.)0.53 mm (0.021 in.) insidediameter fused silica WCOT column with a 2.6-m2.6 m film thickness of cross-linked methyl siloxane. This column was usedin the cooperative study to provide the pre
45、cision 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 15a47. Reagents and Materials7.1 Carrier GasCarrier gas appropriate to the type of detector used. Heli
46、um 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 for establishing identification by retention time as well as calibration for q
47、uantitative 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.
48、 (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 column capable of retaining the C1 to C4alcohols and MTBE, ETBE, DIPE, and TA
49、ME 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 10 g of TCEP in 100 mL 100 mL of methylene chloride. Next add 40 g 40 g of 80/100 meshChromosorb P(AW) to the TCEP solution. Quickly transfer this mixture 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 solvent hasevaporated. This column packing can be used imm
