1、Designation: D7920 15Standard Test Method forDetermination of Fuel Methanol (M99) and Methanol FuelBlends (M10 to M99) by Gas Chromatography1This standard is issued under the fixed designation D7920; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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 the metha-nol content, by gas chromatography
3、, of M10 to M99 inmethanol fuel blends, including fuel methanol (M99).1.1.1 Methanol may be determined from 10 % to 99 % byvolume.1.2 This test method is designed to measure not onlymethanol in the blended gasoline but also the impurities in fuelmethanol (M99) itself in the range of 5 mg/kg to 1000
4、mg/kg.However, not all impurities are measured nor detected by thistest method.1.2.1 Water cannot be determined by this test method andshall be measured by a procedure such as Test Method D1364and the result used to correct the concentrations determined bythis test method.1.3 The values stated in SI
5、 units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health
6、practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1364 Test Method for Water in Volatile Solvents (KarlFischer Reagent Titration Method)D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology R
7、elating to Petroleum, PetroleumProducts, and LubricantsD4307 Practice for Preparation of Liquid Blends for Use asAnalytical StandardsD4814 Specification for Automotive Spark-Ignition EngineFuelD4626 Practice for Calculation of Gas ChromatographicResponse FactorsD5797 Specification for Fuel Methanol
8、(M70-M85) for Au-tomotive Spark-Ignition EnginesD6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE355 Practice
9、 for Gas Chromatography Terms and Relation-shipsE594 Practice for Testing Flame Ionization Detectors Usedin Gas or Supercritical Fluid ChromatographyE1064 Test Method for Water in Organic Liquids by Coulo-metric Karl Fischer TitrationE1510 Practice for Installing Fused Silica Open TubularCapillary C
10、olumns in Gas Chromatographs3. Terminology3.1 This test method makes reference to many commonchromatographic procedures, terms, and relationships. Detaileddefinitions can be found in Terminology D4175 and PracticesD4626, E355, and E594.3.2 Definitions:3.2.1 analyte, na specific compound to be measur
11、edquantitatively in a mixture of compounds.3.2.2 analytical column, na chromatographic column usedto further separate a specific analyte from a mixture ofcompounds which can coelute in the primary column.3.2.3 analytical detector, na device used to quantify thecompounds of interest after they elute
12、from the analyticalcolumn.3.2.4 fuel methanol (M99), nmethyl alcohol produced forthe purpose of blending with gasoline to make a fuel forspark-ignition internal combustion engines.3.2.4.1 DiscussionFuel methanol is typically producedwith 99 % by volume methyl alcohol.1This test method is under the j
13、urisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0L on Gas Chromatography Methods.Current edition approved Aug. 1, 2015. Published September 2015. DOI:10.1520/D7920-15.2For referenced ASTM standards, visit the
14、 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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Un
15、ited States13.2.5 gasoline, na volatile mixture of liquidhydrocarbons, generally containing small amounts ofadditives, suitable for use as a fuel in spark-ignition internalcombustion engines. D48143.2.6 heart-cut, nin gas chromatography, a procedure inwhich the analyte in question is transferred fro
16、m one column toa different column, usually of the opposite polarity.3.2.7 internal standard (IS), na high purity compound notpresent in the sample which is added to the sample and used tocalculate quantitatively the component of interest.3.2.7.1 DiscussionThe internal standard is added in aconstant
17、amount to all calibration standards, see 7.4.2.1.3.2.8 mass response factor (MRF), na constant of propor-tionality that converts area percent to mass percent.3.2.9 methanol, nmethyl alcohol, the chemical compoundCH3OH.3.2.10 methanol fuel blend, na fuel consisting primarily ofa mixture of methanol w
18、ith gasoline.3.2.10.1 DiscussionTypically methanol fuel blends are70 % to 85 % by volume, identified as M70 to M85.3.2.11 microfluidic device, na chromatographic switchingvalve constructed with micro channels, usually having fiveports and to which the columns, restrictors and auxiliarypressure devic
19、es are connected in order to carry out a heart-cut.3.2.11.1 DiscussionAn auxiliary carrier gas is fed to thedevice which has two ports of entry such that switching thecarrier gas from one port to the other results in changing thedirection of the flow of the primary column to either a restrictoror to
20、 the analytical column.3.2.12 monitor detector, na device used to measure theelution of the analyte from the primary column.3.2.12.1 DiscussionThe monitor detector is used to deter-mine the heart-cut time (see 6.1.1), that is, the time where thepeak of interest begins and where the peak of interest
21、ends.3.2.13 MXX, nan abbreviation that represents a fuel con-sisting primarily of methanol (methyl alcohol) and hydrocar-bons in which XXis the percent by volume of methanol in theblended fuel.3.2.14 primary column, nin chromatography, a deviceused to perform a primary separation of a mixture of com
22、-pounds.3.2.14.1 DiscussionThe primary column, also known as amonitor column, is used to separate the analyte of interest andto determine the start time and the end time of the heart-cut.4. Summary of Test Method4.1 The sample is injected in to the gas chromatographwhere components are separated in
23、the primary column andsubsequently are eluted through the restrictor and detected bythe monitor detector. The methanol is identified and theheart-cut window is determined. The instrument settings are setto transfer the methanol from the primary column to theanalytical column. A further separation ta
24、kes place in theanalytical polar column suitable for the polarity of methanol.After elution from the secondary column, the methanol isanalyzed by the analytical detector. Fuel methanol (M99) isanalyzed by the primary column only without the execution ofa heart-cut. Analysis is made in the monitor de
25、tector. In thecase of fuel methanol (M99) the mass percent is determined bydifference.5. Significance and Use5.1 Methanol is used in blends with gasoline at levels of70 % to 85 % by volume, as specified in Specification D5797.This test method provides a quantitative approach to measurethe methanol c
26、ontent in methanol fuel blends, from 10 % to99 % by volume. The usual concentration is 70 % to 85 % byvolume (M70 to M85). The method is also used to analyze fuelmethanol (M99) prior to blending.6. Apparatus6.1 Gas Chromatograph, capable of operating at the condi-tions listed in Table 1 and Table 2.
27、 A heated flash vaporizinginlet, also known as a split inlet, is designed to provide a linearsample split injection (for example, 500:1). This inlet isrequired for proper sample introduction. Carrier gas controlsshall be of adequate precision to provide reproducible columnflows and split ratios in o
28、rder to maintain analytical integrity.Pressure and flow control devices used shall be designed toattain the linear velocity required for optimum operation of thecolumns. Two separate flame ionization detectors are requiredfor this test method. The use of one detector alone is notpossible as the sett
29、ing of the heart-cut times will be difficultand the reliability of the exact cut time determination may becompromised. Detectors should meet the sensitivity criteria ofPractice E594.6.1.1 A heart-cut is a technique which utilizes a switchingdevice to which the following five (5) components are con-n
30、ected: (1) a primary column, usually non-polar which spansfrom the inlet to the device, (2) an analytical column, usuallya polar column, that spans from the device to the analyticaldetector, (3) a restrictor or a tubing of small diameter whichconnects from the device to a second detector whose funct
31、ionis to serve as the monitor detector, (4) an external pressuredevice which controls the pressure at the point where the twoTABLE 1 Conditions for Analysis of Methanol Fuel BlendCarrier HeliumValve ON interval, min 2.372.60 3.253.36Inlet temperature, C 250Split ratio 500/1Primary column pressure, k
32、Pa 259.2Primary column flow, mL/min 2Analytical column pressure, kPa 190.1Analytical column, flow, mL/min 3Oven, initial T C 50Initial hold time, min 5.5Oven temperature rate, C /min 15Final oven temperature, C 190Final hold time, min 3Analytical FID, T C 300Hydrogen, mL/min 45Air, mL/min 450Make up
33、, N2mL/min 25Monitor, FID, T C 300Hydrogen, mL/min 45Air, mL/min 450Make up, N2mL/min 25Volume injected, L 0.2D7920 152columns coincide, and finally, (5), a solenoid that directs thepressure to the two points of the device. By switching theapplied pressure, the components eluting from the primarycol
34、umn can either be sent to the monitor detector or to theanalytical column where further separation occurs and thus thecompounds of interest elute at the analytical detector.6.2 Sample Introduction SystemAutomated liquid injec-tion to the split inlet is required. Devices capable of 0.2 L to2.0 L inje
35、ctions is suitable.6.3 ColumnsThe precision for this test method was devel-oped utilizing fused silica open tubular columns with non-polarpolydimethylsiloxane bonded (cross-linked) phase coating anda polyethylene glycol coated fused silica column.6.3.1 Primary ColumnAn open tubular column with anon-
36、polar polydimethylsiloxane bonded (cross-linked) phasecoating, having 30 m by 0.25 mm with a 0.25 m filmthickness, is used as primary column. This column is installedfrom the split inlet to the microfluidic device. Follow PracticeE1510 for column installation at the split inlet. The column isalso in
37、serted to the proper port of the microfluidic device withan appropriate ferrule. Follow the instructions of the manufac-turer of the microfluidic device when inserting the column andsetting the ferrule to the column. Utmost care is required whenmaking the connection of the ferrule to the device in o
38、rder notto crack the fused silica column.6.3.2 Analytical ColumnA second open tubular column,30 m by 0.25 mm with a film thickness 0.25 m, containing apolyethylene glycol phase which is a polar phase. One end ofthis analytical column is inserted into the microfluidic deviceand the opposite end is co
39、nnected to the analytical detector.Observe the same precautions in making the connections asdescribed in 6.3.1.6.3.3 A balance restrictor is required; composed of inertdeactivated fused silica whose dimensions provide the sameflow resistance as that of the analytical column while minimiz-ing the hol
40、dup time of peaks eluting from the primary columnto the monitor detector. A typical sized restrictor will be ofapproximately1minlength and 0.1 mm internal diameter. Itis connected from the device to the monitor detector. Thislength is sufficient to accommodate the equivalent pneumaticresistance of t
41、he analytical column. The dimensions of therestrictor facilitate the fast transfer of the eluents from theprimary column so as to provide negligible delay in reachingthe monitor detector. Thus accurate cut times can be deter-mined.6.4 Microfluidic DeviceThe microfluidic device shall betreated to bec
42、ome inert in order to avoid adsorption of anycomponents in the sample. It shall be manufactured withextremely small volumes and grooves so as not to introducepeak broadening or dead volumes. These devices are availablefrom several manufacturers.6.5 Electronic Pressure ControlAn electronic means ofco
43、ntrolling the auxiliary pressure is required to cause thetransfer of the components from the primary column to theanalytical column. This controller is connected to the micro-fluidic device through a solenoid. The pressure controller mustbe capable of controlling pressures to within at least 0.069 k
44、Pa.6.6 SolenoidDevice required to switch the direction of theflow from the restrictor point to the analytical column point.Typical solenoids should be capable of executing more thanone million cycles. The solenoid should be free of componentsthat may interfere with the analysis. When the solenoid is
45、 in theoff position the flow of the primary column is sent to theTABLE 2 Conditions for Analysis of Methanol Fuel BlendCarrier HydrogenValve ON interval, min 1.42-1.52 1.942.06Inlet temperature, C 250Split ratio 500/1Primary column pressure, kPa 172.6Primary column flow, mL/min 2.5Analytical column
46、pressure, kPa 120.7Analytical column, flow, mL/min 3.5Oven, initial T C 50Initial hold time, min 5.5Oven temperature rate, C /min 15Final oven temperature, C 190Final hold time, min 3Analytical FID, T C 300Hydrogen, mL/min 45Air, mL/min 450Make up, N2mL/min 25Monitor, FID, T C 300Hydrogen, mL/min 45
47、Air, mL/min 450Make up, N2mL/min 25Volume injected, L 0.2FIG. 1 (a) Heart-cut System Flow to Monitor DetectorD7920 153monitor detector (Fig. 1(a). When the solenoid is in the onposition, the flow of the primary column is sent to theanalytical column and subsequently to the analytical detector(Fig. 1
48、(b). A shunt restrictor is placed across the output of thesolenoid which provides a trickle of flow to the unsweptsection.6.7 The gas chromatograph requires a means to program thepressures required for the transfer of components from theprimary to the analytical column as well as to control the inle
49、tpressure during the analysis so as to perform backflush. It isessential that the gas chromatograph be provided with accurateand reproducible oven temperature control. Control may bethrough hardware or software of the gas chromatograph. Inaddition software is required to integrate the signals andperform internal standard and or external standard calculationsas required.6.8 A data system is required to acquire data and to controlthe gas chromatographs operational variables.Adata system isrequired to perform calibrations and analy
