1、Designation: D5845 01 (Reapproved 2011)Standard Test Method forDetermination of MTBE, ETBE, TAME, DIPE, Methanol,Ethanol and tert-Butanol in Gasoline by InfraredSpectroscopy1This standard is issued under the fixed designation D5845; the number immediately following the designation indicates the year
2、 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of methanol,et
3、hanol, tert-butanol, methyl tert-butyl ether (MTBE), ethyltert-butyl ether (ETBE), tert-amyl methyl ether (TAME), anddiisopropyl ether (DIPE) in gasoline by infrared spectroscopy.The test method is suitable for determining methanol from 0.1to 6 mass %, ethanol from 0.1 to 11 mass %, tert-butanol fro
4、m0.1 to 14 mass %, and DIPE, MTBE, ETBE and TAME from0.1 to 20 mass %.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
5、It is theresponsibility 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:2D1298 Test Method for Density, Relative Density (SpecificGravity), or API Grav
6、ity of Crude Petroleum and LiquidPetroleum Products by Hydrometer MethodD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4307 Practice for Preparation of Liquid Blends for Use asAn
7、alytical StandardsD4815 Test Method for Determination of MTBE, ETBE,TAME, DIPE, tertiary-Amyl Alcohol and C1to C4Alco-hols in Gasoline by Gas ChromatographyD5599 Test Method for Determination of Oxygenates inGasoline by Gas Chromatography and Oxygen SelectiveFlame Ionization DetectionE1655 Practices
8、 for Infrared Multivariate QuantitativeAnalysis2.2 Other Standard:3GC/OFID EPA Test MethodOxygen and Oxygenate Con-tent Analysis (by way of gas chromatography withoxygen-selective flame ionization detection)3. Terminology3.1 Definitions:3.1.1 multivariate calibration, na process for creating acalibr
9、ation model in which multivariate mathematics is appliedto correlate the absorbances measured for a set of calibrationsamples to reference component concentrations or propertyvalues for the set of samples. The resultant multivariatecalibration model is applied to the analysis of spectra ofunknown sa
10、mples to provide an estimate of the componentconcentration or property values for the unknown sample.3.1.2 oxygenate, nan oxygen-containing organic com-pound, which may be used as a fuel or fuel supplement, forexample, various alcohols or ethers.4. Summary of Test Method4.1 A sample of gasoline is i
11、ntroduced into a liquid samplecell. A beam of infrared light is imaged through the sampleonto a detector, and the detector response is determined.Regions of the infrared spectrum are selected for use in theanalysis by either placing highly selective bandpass filtersbefore or after the sample or math
12、ematically selecting theregions after the whole spectrum is obtained. A multivariatemathematical analysis is carried out which converts the detec-tor response for the selected regions in the spectrum of anunknown to a concentration for each component.5. Significance and Use5.1 Alcohols and ethers ar
13、e added to gasoline to produce areformulated lower emissions gasoline. Alcohols and ethers1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.04.0F on Absorption Spectroscopic Methods.Current editio
14、n approved Oct. 1, 2011. Published November 2011. Originallyapproved in 1995. Last previous edition approved in 2006 as D584501(2006).DOI: 10.1520/D5845-01R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
15、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Code of Federal Regulations, Part 80 of Title 40, Section 80.46(g); alsopublished in the Federal Register, Volume 59, No. 32, February 16, 1994, p 7828.1Copyright ASTM International, 100 Barr Harbor Dr
16、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.may also be added to gasoline to increase the octane number.Type and concentration of various oxygenates are specified andregulated to ensure acceptable commercial gasoline quality.Driveability, vapor pressure, phase separation, and e
17、vaporativeemissions are some of the concerns associated with oxygenatedfuels.5.2 This test method is faster, simpler, less expensive andmore portable than current methods.5.3 This test method may be applicable for quality control inthe production of gasoline.5.4 This test method is not suitable for
18、testing for compli-ance with federal regulations.35.5 False positive readings for some of the samples tested inthe round robin were sometimes observed. As only extremebase gasolines were tested in the round robin, no definitivestatement can be made as to the expected frequency ormagnitude of false p
19、ositives expected in a wider range of basegasolines.6. Apparatus6.1 Mid-IR Spectrometric Analyzer, of one of the followingtypes:6.1.1 Filter-based Mid-IR Test ApparatusThe type ofapparatus suitable for use in this test method minimallyemploys an IR source, an infrared transmission cell or a liquidat
20、tenuated total internal reflection cell, wavelength discrimi-nating filters, a chopper wheel, a detector, an A-D converter, amicroprocessor, and a sample introduction system.6.1.2 Fourier Transform Mid-IR Test ApparatusThe typeof apparatus suitable for use in this test method employs an IRsource, an
21、 infrared transmission cell or a liquid attenuated totalinternal reflection cell, a scanning interferometer, a detector, anA-D converter, a microprocessor and a sample introductionsystem.6.1.3 Dispersive Mid-IR Test ApparatusThe type of appa-ratus suitable for use in this test method minimally emplo
22、ys anIR source, an infrared transmission cell or a liquid attenuatedtotal internal reflection cell, a wavelength dispersive elementsuch as a grating or prism, a chopper wheel, a detector, an A-Dconverter, a microprocessor and a sample introduction system.7. Reagents and Materials7.1 Samples for Cali
23、bration and Quality Control CheckSolutionsUse of chemicals of at least 99 % purity is highlyrecommended when preparing calibration and quality controlcheck samples. If reagents of high purity are not available, anaccurate assay of the reagent must be performed using aproperly calibrated GC or other
24、techniques (for example, waterdetermination).7.1.1 Base gasolines containing no oxygenates,7.1.2 Methanol,7.1.3 Ethanol,7.1.4 tert-Butanol,7.1.5 Methyl tert-butyl ether, MTBE,7.1.6 Ethyl tert-butyl ether, ETBE,7.1.7 tert-Amyl methyl ether, TAME, and7.1.8 Diisopropyl ether, DIPE.7.2 WarningThese mate
25、rials are flammable and may beharmful if ingested or inhaled.8. Sampling and Sample Handling8.1 General Requirements:8.1.1 Gasoline samples must be handled with meticulouscare to prevent evaporative loss and composition changes.8.1.2 Gasoline samples to be analyzed by the test methodshall be obtaine
26、d using method(s) specified by governmentalregulatory agencies or by the procedures outlined in PracticeD4057 (or equivalent). Do not use the “Sampling by WaterDisplacement” method as some alcohols or ethers might beextracted into the water phase.8.1.3 Protect samples from excessive temperatures pri
27、or totesting. This can be accomplished by storage in an appropriateice bath or refrigerator at 0 to 5C.8.1.4 Do not test samples stored in leaky containers. Discardand obtain a new sample if leaks are detected.8.1.5 Perform the oxygenate determination on fresh samplesfrom containers that are at leas
28、t 80 % full. If sample containersare less than 80 % full or have been opened and sampledmultiple times, a new sample shall be obtained.8.2 Sample Handling During Analysis:8.2.1 Prior to the analysis of samples by infrared spectros-copy, the samples should be allowed to equilibrate to thetemperature
29、at which they should be analyzed (15 to 38C).8.2.2 After withdrawing the sample, reseal the container,and store the sample in an ice bath or a refrigerator at 0 to 5C.9. Preparation, Calibration, and Qualification of theInfrared Test Apparatus9.1 PreparationPrepare the instrument for operation inacc
30、ordance with the manufacturers instructions.9.2 CalibrationEach instrument must be calibrated by themanufacturer or user in accordance with Practice E1655. Thispractice serves as a guide for the multivariate calibration ofinfrared spectrometers used in determining the physical char-acteristics of pe
31、troleum and petrochemical products. Theprocedures describe treatment of the data, development of thecalibration, and qualification of the instrument. Note that biasand slope adjustments are specifically not recommended toimprove calibration or prediction statistics for IR multivariatemodels.9.3 Qual
32、ification of InstrumentThe instrument must bequalified according to the procedure inAnnexA1 to ensure thatthe instrument accurately and precisely measures each oxygen-ate in the presence of typical gasoline compounds or otheroxygenates that, in typical concentrations, present spectralinterferences.
33、General classes of compounds that will causeinterferences include aromatics, branched aliphatic hydrocar-bons, and other oxygenates.10. Quality Control Standards10.1 Confirm the proper operation of the instrument eachday it is used by analyzing at least one quality control standardof known oxygenate
34、 content for each oxygenate to be deter-mined. These standards should be made up by mass accordingto Practice D4307 and should be at the expected concentrationlevel for that oxygenate. The recommended quality controlstandard concentrations are found in Table 1.10.2 The individual oxygenate values ob
35、tained must agreewithin 6 5 % relative of the values in the prepared qualityD5845 01 (2011)2control standard (for example, MTBE 14.0 6 0.7 mass %) orto within 6 0.3 mass % absolute, whichever is greater (forexample, methanol 4.0 6 0.3 mass % ). If the individual valuesare outside the specified range
36、, recalibrate the instrumentaccording to the procedures in 9.2. The quality control stan-dards should not be used for the calibration or recalibration ofthe instrument. Do not analyze samples without meeting thequality control specifications.11. Procedure11.1 Equilibrate the samples to between 15 an
37、d 38C beforeanalysis.11.2 Follow the manufacturers instructions for establishinga baseline for the instrument, introducing a sample into thesample cell and operating the instrument. If the instructionscall for a non-oxygenated gasoline to be used in establishingthe baseline, use a non-oxygenated gas
38、oline that is differentfrom the non-oxygenated gasolines used in the preparation ofeither calibration standards, validation of qualification samples,or quality control standards.11.3 Thoroughly clean the sample cell by introducingenough sample to the cell to ensure the cell is washed aminimum of thr
39、ee times with the test solution.11.4 Establish that the equipment is running properly byrunning the quality control standards prior to the analysis ofunknown test samples (see Section 10).11.5 Introduce the sample in the manner established by themanufacturer. Obtain the concentration reading produce
40、d bythe instrument.12. Calculation12.1 Conversion to Mass Concentration of OxygenatesIfthe instrument readings are in volume % for each component,convert the results to mass % according to Eq 1:mi5 ViDi/Df! (1)where:mi= mass % for each oxygenate to be determined,Vi= volume % of each oxygenate,Di= re
41、lative density at 15.56C of the individual oxygen-ate as found in Table 2,Df= relative density of the fuel at 15.56C under study asdetermined by Practice D1298 or Test Method D4052.If the density has not been measured, an assumeddensity of 0.742 should be used.12.2 Total Mass % OxygenTo determine th
42、e total oxygencontent of the fuel, sum the mass % oxygen contents of alloxygenate components determined above according to Eq 2:Wtot5 ( mi3 16.0 3 Ni!/Mi# (2)where:Wtot= total mass % oxygen in the fuel,mi= mass % for each oxygenate,16.0 = atomic mass of oxygen,Ni= number of oxygen atoms in the oxyge
43、nate mol-ecule, andMi= molecular mass of the oxygenate molecule as givenin Table 2.13. Report13.1 Report results of each oxygenate and the total oxygento the nearest 0.1 mass %.14. Precision and Bias414.1 The precision of the method as obtained by statisticalexamination of interlaboratory results is
44、 as follows:14.2 RepeatabilityThe difference between successive testresults, obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe test method exceed the following values on
45、ly in one case intwenty:Oxygenate Repeatability (mass %)MTBE 0.13TAME 0.13ETBE 0.15Ethanol 0.13Methanol 0.07t-Butanol 0.10DIPE 0.14Total Oxygen Content 0.0514.3 ReproducibilityThe difference between two singleand independent results, obtained by different operators work-ing in different laboratories
46、 on identical test materials would, inthe long run, exceed the following values only in one case intwenty:Oxygenate Reproducibility (mass %)MTBE 0.98TAME 1.36ETBE 0.77Ethanol 0.59Methanol 0.37t-Butanol 0.59DIPE 0.79Total Oxygen Content 0.304Supporting data have been filed at ASTM International Headq
47、uarters and maybe obtained by requesting Research Report RR:D02-1374.TABLE 1 Recommended Concentrations for Individual QualityControl StandardsOxygenateConcentration to Attain2.0 mass % O 2.7 mass % O 3.5 mass % OMethanol 4.00 mass % 5.41 mass %Ethanol 5.76 mass % 7.77 mass % 10.1 mass %tert-Butanol
48、 9.26 mass % 12.5 mass %MTBE 11.0 mass % 14.9 mass %TAME 12.8 mass % 17.2 mass %DIPE 12.8 mass % 17.2 mass %ETBE 12.8 mass % 17.2 mass %TABLE 2 Pertinent Physical ConstantsComponent CAS Number Molecular MassRelative Density,15.56CMethanol 67-56-1 32.04 0.7963Ethanol 64-17-5 46.07 0.7939tert-Butanol
49、75-65-0 74.12 0.7922MTBE 1634-04-4 88.15 0.7460DIPE 108-20-3 102.18 0.7300ETBE 637-92-3 102.18 0.7452TAME 994-05-8 102.18 0.7758D5845 01 (2011)314.4 BiasNo consistent bias was observed with thesamples tested in the round robin and since a wide range ofbase gasolines was not tested, it is not possible to offer adefinitive statement of bias except to note that biases wereobserved in the round robin.15. Keywords15.1 alcohols; diisopropyl ether; ethanol; ethers; ethyl tert-butyl ether; methanol; methyl tert-butyl ether; motor gasoline;oxygenate;tert-amyl met
