ASTM D7920-21

Standard Test Method for Determination of Fuel Methanol (M99) and Methanol Fuel Blends (M10 to M99) by Gas Chromatography

SIGNIFICANCE AND USE
5.1 Methanol is used in blends with gasoline at levels of 70 % to 85 % by volume, as specified in Specification D5797. This test method provides a quantitative approach to measure the methanol content in methanol fuel blends, from 10 % to 99 % by volume. The usual concentration is 70 % to 85 % by volume (M70 to M85). The method is also used to analyze fuel methanol (M99) prior to blending.
SCOPE
1.1 This test method covers the determination of the methanol content, by gas chromatography, of M10 to M99 in methanol fuel blends, including fuel methanol (M99).  
1.1.1 Methanol may be determined from 10 % to 99 % by volume.  
1.2 This test method is designed to measure not only methanol in the blended gasoline but also the impurities in fuel methanol (M99) itself in the range of 5 mg/kg to 1000 mg/kg. However, not all impurities are measured nor detected by this test method.  
1.2.1 Water cannot be determined by this test method and shall be measured by a procedure such as Test Method D1364 and the result used to correct the concentrations determined by this test method.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Dec-2020
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0L - Gas Chromatography Methods

Relations

• Refers: ASTM D4814-24 - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Jan-2024
• Refers: ASTM E1064-24 - Standard Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration
• Effective Date: 01-Jan-2024
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D6299-23a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Dec-2023
• Refers: ASTM D4814-23a - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Dec-2023
• Refers: ASTM D4626-23 - Standard Practice for Calculation of Gas Chromatographic Response Factors
• Effective Date: 01-Oct-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D4814-20 - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Feb-2020
• Refers: ASTM D4626-95(2019) - Standard Practice for Calculation of Gas Chromatographic Response Factors
• Effective Date: 01-Dec-2019
• Refers: ASTM D4814-19a - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Dec-2019
• Refers: ASTM E594-96(2019) - Standard Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
• Effective Date: 01-Sep-2019
• Refers: ASTM D4814-18c - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Oct-2018
• Refers: ASTM D4814-18a - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Apr-2018
• Refers: ASTM D4814-18 - Standard Specification for Automotive Spark-Ignition Engine Fuel
• Effective Date: 01-Jan-2018
• Refers: ASTM D6299-17b - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Dec-2017

Overview

ASTM D7920-21 is an important international standard developed by ASTM International, entitled Standard Test Method for Determination of Fuel Methanol (M99) and Methanol Fuel Blends (M10 to M99) by Gas Chromatography. This document outlines the procedures for accurately determining the methanol content in fuel methanol (M99) and a range of methanol-gasoline blends (M10 to M99), using gas chromatography (GC) techniques. The standard is vital for industries focused on fuel quality, regulatory compliance, and research regarding alternative fuels.

Methanol is frequently used as an alternative fuel and as a high-blend component with gasoline, particularly at concentrations from 70% to 85% by volume (M70 to M85). ASTM D7920-21 supports the automotive industry, fuel producers, laboratories, and regulatory bodies by providing a robust method to confirm the methanol content and detect select impurities in these fuel blends.

Key Topics

• Scope and Coverage: The method applies to the determination of methanol concentrations ranging from 10% to 99% by volume in methanol-gasoline fuel blends.
• Instrumental Approach: Utilizes gas chromatography with particular column and detector arrangements to separate and quantify methanol and certain impurities.
• Impurity Analysis: Enables quantification of major impurities in fuel methanol (M99) from 5 mg/kg up to 1000 mg/kg, though not all possible impurities are detectable by this technique.
• Calibration and Quality Control: Specifies the preparation of calibration standards and internal standards, including the use of ethyl acetate, for precise methanol quantification.
• Sample Handling: Provides guidance on sample collection, preparation, and system verification to ensure analytical accuracy and repeatability.
• Limitations: The method does not measure water content in fuels; a separate standard, such as ASTM D1364, is recommended for determining water concentrations.

Applications

Implementing ASTM D7920-21 delivers practical benefits for several sectors:

• Fuel Producers and Blenders: Ensures methanol fuel blends comply with regulatory requirements regarding composition, supporting quality control during production and blending operations.
• Regulatory Compliance: Assists laboratories in verifying fuel compositions as mandated by national regulations and emission standards.
• Automotive Industry: Provides accurate methanol content data for manufacturers of methanol-compatible and flexible-fuel vehicles, aiding in engine calibration and warranty compliance.
• Research and Development: Facilitates studies into fuel behavior, emissions performance, and optimization of methanol-gasoline blends for alternative energy solutions.
• Quality Assurance: Supports ongoing monitoring through statistical quality control practices, critical for maintaining fuel consistency across batches.

Related Standards

Professionals utilizing ASTM D7920-21 may also benefit from familiarity with these related standards:

• ASTM D5797: Specification for Methanol Fuel Blends (M51–M85) for Methanol-Capable Automotive Spark-Ignition Engines.
• ASTM D1364: Test Method for Water in Volatile Solvents (for complementary water determination in fuels).
• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products.
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants.
• ASTM D4626: Practice for Calculation of Gas Chromatographic Response Factors.
• ASTM D4814: Specification for Automotive Spark-Ignition Engine Fuel.

Conclusion

Adopting ASTM D7920-21 is essential for accurate methanol measurement in fuel methanol and methanol fuel blends using gas chromatography. This standard enhances analytical integrity, regulatory compliance, and quality control for those involved in the production and use of methanol-based fuels, promoting reliability and safety in the evolving fuel landscape.

Keywords: ASTM D7920-21, methanol fuel blends, M99, M10, gas chromatography, fuel quality, fuel methanol, impurity analysis, calibration standards, automotive fuel testing, regulatory compliance.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7920 − 21
Standard Test Method for
Determination of Fuel Methanol (M99) and Methanol Fuel
Blends (M10 to M99) by Gas Chromatography
This standard is issued under the fixed designation D7920; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* D1364 Test Method for Water in Volatile Solvents (Karl
Fischer Reagent Titration Method)
1.1 This test method covers the determination of the metha-
D4057 Practice for Manual Sampling of Petroleum and
nol content, by gas chromatography, of M10 to M99 in
Petroleum Products
methanol fuel blends, including fuel methanol (M99).
D4175 Terminology Relating to Petroleum Products, Liquid
1.1.1 Methanol may be determined from 10 % to 99 % by
Fuels, and Lubricants
volume.
D4307 Practice for Preparation of Liquid Blends for Use as
1.2 This test method is designed to measure not only
Analytical Standards
methanol in the blended gasoline but also the impurities in fuel
D4814 Specification for Automotive Spark-Ignition Engine
methanol (M99) itself in the range of 5 mg/kg to 1000 mg/kg.
Fuel
However, not all impurities are measured nor detected by this
D4626 Practice for Calculation of Gas Chromatographic
test method.
Response Factors
1.2.1 Water cannot be determined by this test method and
D5797 Specification for Methanol Fuel Blends (M51–M85)
shall be measured by a procedure such as Test Method D1364
forMethanol-CapableAutomotiveSpark-IgnitionEngines
and the result used to correct the concentrations determined by
D6299 Practice for Applying Statistical Quality Assurance
this test method.
and Control Charting Techniques to Evaluate Analytical
1.3 The values stated in SI units are to be regarded as Measurement System Performance
E29 Practice for Using Significant Digits in Test Data to
standard. No other units of measurement are included in this
standard. Determine Conformance with Specifications
E355 Practice for Gas Chromatography Terms and Relation-
1.4 This standard does not purport to address all of the
ships
safety concerns, if any, associated with its use. It is the
E594 Practice for Testing Flame Ionization Detectors Used
responsibility of the user of this standard to establish appro-
in Gas or Supercritical Fluid Chromatography
priate safety, health, and environmental practices and deter-
E1064 Test Method for Water in Organic Liquids by Coulo-
mine the applicability of regulatory limitations prior to use.
metric Karl Fischer Titration
1.5 This international standard was developed in accor-
E1510 Practice for Installing Fused Silica Open Tubular
dance with internationally recognized principles on standard-
Capillary Columns in Gas Chromatographs
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3. Terminology
mendations issued by the World Trade Organization Technical
3.1 This test method makes reference to many common
Barriers to Trade (TBT) Committee.
chromatographicprocedures,terms,andrelationships.Detailed
2. Referenced Documents definitions can be found in Terminology D4175 and Practices
D4626, E355, and E594.
2.1 ASTM Standards:
3.2 Definitions:
3.2.1 analyte, n—a specific compound to be measured
This test method is under the jurisdiction of ASTM Committee D02 on
quantitatively in a mixture of compounds.
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.04.0L on Gas Chromatography Methods.
3.2.2 analyticalcolumn,n—achromatographiccolumnused
Current edition approved Jan. 1, 2021. Published January 2021. Originally
to further separate a specific analyte from a mixture of
ɛ1
approved in 2015. Last previous edition approved in 2015 as D7920 – 15 . DOI:
compounds which can coelute in the primary column.
10.1520/D7920-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
3.2.3 analytical detector, n—a device used to quantify the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
compounds of interest after they elute from the analytical
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. column.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7920 − 21
3.2.4 fuel methanol (M99), n—methyl alcohol produced for to transfer the methanol from the primary column to the
the purpose of blending with gasoline to make a fuel for analytical column. A further separation takes place in the
spark-ignition internal combustion engines. analytical polar column suitable for the polarity of methanol.
3.2.4.1 Discussion—Fuel methanol is typically produced After elution from the secondary column, the methanol is
with 99 % by volume methyl alcohol. analyzed by the analytical detector. Fuel methanol (M99) is
analyzed by the primary column only without the execution of
3.2.5 gasoline, n—a volatile mixture of liquid
a heart-cut. Analysis is made in the monitor detector. In the
hydrocarbons, generally containing small amounts of
case of fuel methanol (M99) the mass percent is determined by
additives, suitable for use as a fuel in spark-ignition internal
difference.
combustion engines. D4814
3.2.6 heart-cut, n—in gas chromatography, a procedure in
5. Significance and Use
whichtheanalyteinquestionistransferredfromonecolumnto
5.1 Methanol is used in blends with gasoline at levels of
a different column, usually of the opposite polarity.
70 % to 85 % by volume, as specified in Specification D5797.
3.2.7 internal standard (IS), n—a high purity compound not
This test method provides a quantitative approach to measure
present in the sample which is added to the sample and used to
the methanol content in methanol fuel blends, from 10 % to
calculate quantitatively the component of interest.
99 % by volume. The usual concentration is 70 % to 85 % by
3.2.7.1 Discussion—The internal standard is added in a
volume (M70 to M85).The method is also used to analyze fuel
constant amount to all calibration standards, see 7.4.2.1.
methanol (M99) prior to blending.
3.2.8 mass response factor (MRF), n—a constant of propor-
6. Apparatus
tionality that converts area percent to mass percent.
6.1 Gas Chromatograph, capable of operating at the condi-
3.2.9 methanol, n—methyl alcohol, the chemical compound
tions listed in Table 1 and Table 2. A heated flash vaporizing
CH OH.
inlet, also known as a split inlet, is designed to provide a linear
3.2.10 methanolfuelblend,n—afuelconsistingprimarilyof
sample split injection (for example, 500:1). This inlet is
a mixture of methanol with gasoline.
required for proper sample introduction. Carrier gas controls
3.2.10.1 Discussion—Typically methanol fuel blends are
shall be of adequate precision to provide reproducible column
70 % to 85 % by volume, identified as M70 to M85.
flows and split ratios in order to maintain analytical integrity.
3.2.11 microfluidic device, n—a chromatographic switching
Pressure and flow control devices used shall be designed to
valve constructed with micro channels, usually having five
attain the linear velocity required for optimum operation of the
ports and to which the columns, restrictors and auxiliary
columns. Two separate flame ionization detectors are required
pressuredevicesareconnectedinordertocarryoutaheart-cut.
for this test method. The use of one detector alone is not
3.2.11.1 Discussion—An auxiliary carrier gas is fed to the
possible as the setting of the heart-cut times will be difficult
device which has two ports of entry such that switching the
and the reliability of the exact cut time determination may be
carrier gas from one port to the other results in changing the
compromised. Detectors should meet the sensitivity criteria of
directionoftheflowoftheprimarycolumntoeitherarestrictor
Practice E594.
or to the analytical column.
6.1.1 A heart-cut is a technique which utilizes a switching
3.2.12 monitor detector, n—a device used to measure the
device to which the following five (5) components are con-
elution of the analyte from the primary column. nected: (1) a primary column, usually non-polar which spans
3.2.12.1 Discussion—The monitor detector is used to deter-
from the inlet to the device, (2) an analytical column, usually
mine the heart-cut time (see 6.1.1), that is, the time where the
peak of interest begins and where the peak of interest ends.
TABLE 1 Conditions for Analysis of Methanol Fuel Blend—
Carrier Helium
3.2.13 MXX, n—an abbreviation that represents a fuel con-
Valve ON interval, min 2.37–2.60 3.25–3.36
sisting primarily of methanol (methyl alcohol) and hydrocar-
Inlet temperature, °C 250
bonsinwhich‘XX’isthepercentbyvolumeofmethanolinthe
Split ratio 500/1
blended fuel.
Primary column pressure, kPa 259.2
Primary column flow, mL/min 2
3.2.14 primary column, n—in chromatography, a device
Analytical column pressure, kPa 190.1
used to perform a primary separation of a mixture of com-
Analytical column, flow, mL/min 3
Oven, initial T °C 50
pounds.
Initial hold time, min 5.5
3.2.14.1 Discussion—The primary column, also known as a
Oven temperature rate, °C /min 15
monitor column, is used to separate the analyte of interest and Final oven temperature, °C 190
Final hold time, min 3
to determine the start time and the end time of the heart-cut.
Analytical FID, T °C 300
Hydrogen, mL/min 45
4. Summary of Test Method
Air, mL/min 450
Make up, N mL/min 25
4.1 The sample is injected in to the gas chromatograph
Monitor, FID, T °C 300
where components are separated in the primary column and Hydrogen, mL/min 45
Air, mL/min 450
subsequently are eluted through the restrictor and detected by
Make up, N mL/min 25
the monitor detector. The methanol is identified and the
Volume injected, µL 0.2
heart-cutwindowisdetermined.Theinstrumentsettingsareset
D7920 − 21
TABLE 2 Conditions for Analysis of Methanol Fuel Blend—
6.3.3 A balance restrictor is required; composed of inert
Carrier Hydrogen
deactivated fused silica whose dimensions provide the same
Valve ON interval, min 1.42-1.52 1.94–2.06
flow resistance as that of the analytical column while minimiz-
Inlet temperature, °C 250
ing the holdup time of peaks eluting from the primary column
Split ratio 500/1
to the monitor detector. A typical sized restrictor will be of
Primary column pressure, kPa 172.6
Primary column flow, mL/min 2.5
approximately1min length and 0.1 mm internal diameter. It
Analytical column pressure, kPa 120.7
is connected from the device to the monitor detector. This
Analytical column, flow, mL/min 3.5
Oven, initial T °C 50 length is sufficient to accommodate the equivalent pneumatic
Initial hold time, min 5.5
resistance of the analytical column. The dimensions of the
Oven temperature rate, °C /min 15
restrictor facilitate the fast transfer of the eluents from the
Final oven temperature, °C 190
Final hold time, min 3 primary column so as to provide negligible delay in reaching
Analytical FID, T °C 300
the monitor detector. Thus accurate cut times can be deter-
Hydrogen, mL/min 45
mined.
Air, mL/min 450
Make up, N mL/min 25
6.4 Microfluidic Device—The microfluidic device shall be
Monitor, FID, T °C 300
treated to become inert in order to avoid adsorption of any
Hydrogen, mL/min 45
Air, mL/min 450
components in the sample. It shall be manufactured with
Make up, N mL/min 25
extremely small volumes and grooves so as not to introduce
Volume injected, µL 0.2
peak broadening or dead volumes. These devices are available
from several manufacturers.
6.5 Electronic Pressure Control—An electronic means of
controlling the auxiliary pressure is required to cause the
a polar column, that spans from the device to the analytical
transfer of the components from the primary column to the
detector, (3) a restrictor or a tubing of small diameter which
analytical column. This controller is connected to the micro-
connects from the device to a second detector whose function
fluidic device through a solenoid. The pressure controller must
is to serve as the monitor detector, (4) an external pressure
becapableofcontrollingpressurestowithinatleast0.069kPa.
device which controls the pressure at the point where the two
6.6 Solenoid—Device required to switch the direction of the
columns coincide, and finally, (5), a solenoid that directs the
flow from the restrictor point to the analytical column point.
pressure to the two points of the device. By switching the
Typical solenoids should be capable of executing more than
applied pressure, the components eluting from the primary
one million cycles. The solenoid should be free of components
column can either be sent to the monitor detector or to the
thatmayinterferewiththeanalysis.Whenthesolenoidisinthe
analytical column where further separation occurs and thus the
off position the flow of the primary column is sent to the
compounds of interest elute at the analytical detector.
monitor detector (Fig. 1(a)). When the solenoid is in the on
6.2 Sample Introduction System—Automated liquid injec-
position, the flow of the primary column is sent to the
tion to the split inlet is required. Devices capable of 0.2 µL to
analytical column and subsequently to the analytical detector
2.0 µL injections is suitable.
(Fig. 1(b)).Ashunt restrictor is placed across the output of the
6.3 Columns—The precision for this test method was devel-
solenoid which provides a trickle of flow to the unswept
opedutilizingfusedsilicaopentubularcolumnswithnon-polar
section.
polydimethylsiloxane bonded (cross-linked) phase coating and
6.7 The gas chromatograph requires a means to program the
a polyethylene glycol coated fused silica column.
pressures required for the transfer of components from the
6.3.1 Primary Column—An open tubular column with a
primary to the analytical column as well as to control the inlet
non-polar polydimethylsiloxane bonded (cross-linked) phase
pressure during the analysis so as to perform backflush. It is
coating, having 30 m by 0.25 mm with a 0.25 µm film
essential that the gas chromatograph be provided with accurate
thickness, is used as primary column. This column is installed
and reproducible oven temperature control. Control may be
from the split inlet to the microfluidic device. Follow Practice
through hardware or software of the gas chromatograph. In
E1510 for column installation at the split inlet. The column is
addition software is required to integrate the signals and
also inserted to the proper port of the microfluidic device with
perform internal standard and or external standard calculations
an appropriate ferrule. Follow the instructions of the manufac-
as required.
turer of the microfluidic device when inserting the column and
6.8 A data system is required to acquire data and to control
setting the ferrule to the column. Utmost care is required when
thegaschromatograph’soperationalvariables.Adatasystemis
making the connection of the ferrule to the device in order not
required to perform calibrations and analysis in the internal
to crack the fused silica column.
standard mode. The data systems require that sample mass and
6.3.2 Analytical Column—A second open tubular column,
internal standard mass be entered. The calculation of response
30 m by 0.25 mm with a film thickness 0.25 µm, containing a
factors are described in Practice D4626.
polyethylene glycol phase which is a polar phase. One end of
this analytical column is inserted into the microfluidic device
7. Reagents and Materials
and the opposite end is connected to the analytical detector.
Observe the same precautions in making the connections as 7.1 Reagent grade chemicals shall be used in all tests.
described in 6.3.1. Unless otherwise indicated, it is intended that all reagents shall
D7920 − 21
FIG. 1 (a) Heart-cut System Flow to Monitor Detector
FIG. 1 (b) Heart-cut System Flow to Analytical Detector (continued)
conform to the specifications of the committee on Analytical 7.3 Detector Gases—Hydrogen,air,andnitrogen.Themini-
Reagents of the American Chemical Society, where such mum purity of the gases used should be 99.95 % for the
specifications are available. Consult Practice D4307 in the hydrogen and nitrogen. The air should be hydrocarbon-free
preparation of standard blends. grade. Gas purifiers are recommended for the detector gases.
7.4 Standards for Calibration and Identification—Standards
7.2 Carrier Gas—Helium or hydrogen having at least a
of all components to be analyzed are required for establishing
minimum purity of 99.95 % can be used as carrier gas. Oxygen
identification by retention time as well as for the preparation of
removalsystemsandgaspurifiersshouldbeused.(Warning—
calibration standards for quantitative measurements. These
Helium and hydrogen are compressed gases under high pres-
materials shall be of known purity and free of the other
sure). (Warning—Hydrogen carrier gas requires additional
components to be analyzed.
safety considerations due to its high flammability and potential
7.4.1 Methanol—(Warning—Flammableandmaybeharm-
forexplosions.Theuseofhydrogensensorsforthedetectionof
fulorfatal,ifingestedorinhaled.)Minimumpurityrequiredof
hydrogen leaks in the GC oven is highly recommended. These
atleast99%byvolumeandfreeofethanol.Itisrecommended
devices should be capable of shutting the hydrogen flow to the
that the methanol used in calibration blends be stored over
gas chromatograph.)
anhydrous sodium sulfate. Water content of the methanol is
required for the analysis. Refer to Test Method E1064.
7.4.2 Ethyl Acetate—(Warning—Flammable and may be
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
harmful or fatal, if ingested or inhaled.)This compound is used
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
as the internal standard.
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
7.4.2.1 The internal standard is added in a constant amount
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
copeial Convention, Inc. (USPC), Rockville, MD. to all calibration standards containing the analyte of interest.A
D7920 − 21
plot of the ratio of the area of analyte to internal standard 7.7 Preparation of Standards for Fuel Methanol (M99):
versustheamountofanalytetointernalstandardyieldsalinear
7.7.1 Response Factor Solution—For the analysis of fuel
relationship. The ensuing linear relationship is used to deter-
methanol, prepare a standard solution containing the compo-
mine the concentration of the analyte in the sample.
nents in 7.4.5 at approximately 50 mg/kg. First prepare a stock
7.4.3 Diluent—1,2-Dimethoxy ethane (>99 % and
solution by weighing, to the nearest 0.1 mg, approximately
anhydrous), methanol free, is used for preparation of calibra-
0.100 g of each component listed in 7.4.5 into a 100 mL
tionstandards.Thisdiluentshallbefreeofanycompoundsthat
volumetric flask. Add reagent grade methanol as the solvent
coelute with methanol and ethyl acetate. (Warning—
and record the mass of methanol. This will yield a stock
Flammableandmaybeharmfulorfatal,ifingestedorinhaled.)
solution of approximately 1260 mg/kg of each component.
7.4.4 Gasoline—Used alternatively as a diluent and as
Further prepare a second solution by pipetting 1.0 mL of the
verification of the absence of interfering compounds. The
stock solution and diluting with methanol in a 25 mLvolumet-
gasoline shall be free of methanol and ethyl acetate. This can ric flask. Record the mass in each step so as to determine the
be accomplished by analyzing the diluent gasoline as a sample.
concentrations by mass. The second solution is approximately
Verifythatthechromatogramsdonotshowthepresenceofany 50 mg/kg and is used to determine the response factors of the
other component that coelutes with methanol or ethyl acetate.
impurities. Calculate the concentration of the impurity in the
7.4.5 Impurities in Fuel Methanol (M99)—The following
final solution (C) in mg/kg using the following equation:
i
additional chemicals are required to determine the response
~C ! 5 ~@w ⁄ ~w 1 wm !# 3 w 3 10 !⁄~w 1 wm ! (1)
i 1 1 1 2 2 2
factors of the impurities in the fuel methanol. These chemicals
where:
should be at least of the purity defined in 7.1: ethanol, acetone,
isopropanol, n-propanol, 2-butanol, isobutanol, and 1-butanol.
w = mass of the impurity in the first solution,
(Warning—All of these chemicals are flammable and may be wm = the mass of methanol in the first solution,
w = the mass of the aliquot of the first solution, and
harmful or fatal, if ingested or inhaled.)
wm = is the mass of methanol of the second solution.
7.5 Calibration Mixtures—There are two types of calibra-
tion procedures required. One set of calibration mixtures is
8. Sampling
used for the analysis of fuel methanol (M99). The other
calibrationmixturesareusedfortheanalysisofmethanolinthe 8.1 Fuel methanol may be sampled into an open container
methanol fuel blends. since a vapor pressure of less than 21 kPa (3 psi) is expected.
7.5.1 Glassware—Volumetric flasks 25 mL and 100 mL Refer to Practice D4057 for instructions on manual sampling
class A are requ
...

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 version. Because
it 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 version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D7920 − 15 D7920 − 21
Standard Test Method for
Determination of Fuel Methanol (M99) and Methanol Fuel
Blends (M10 to M99) by Gas Chromatography
This standard is issued under the fixed designation D7920; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Section 16 was corrected editorially in September 2015.
1. Scope Scope*
1.1 This test method covers the determination of the methanol content, by gas chromatography, of M10 to M99 in methanol fuel
blends, including fuel methanol (M99).
1.1.1 Methanol may be determined from 10 % to 99 % by volume.
1.2 This test method is designed to measure not only methanol in the blended gasoline but also the impurities in fuel methanol
(M99) itself in the range of 5 mg/kg to 1000 mg/kg. However, not all impurities are measured nor detected by this test method.
1.2.1 Water cannot be determined by this test method and shall be measured by a procedure such as Test Method D1364 and the
result used to correct the concentrations determined by this test method.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D1364 Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D4814 Specification for Automotive Spark-Ignition Engine Fuel
D4626 Practice for Calculation of Gas Chromatographic Response Factors
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.04.0L on Gas Chromatography Methods.
Current edition approved Aug. 1, 2015Jan. 1, 2021. Published September 2015January 2021. Originally approved in 2015. Last previous edition approved in 2015 as
ɛ1
D7920 – 15 . DOI: 10.1520/D7920-15E01.10.1520/D7920-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D5797 Specification for Methanol Fuel Blends (M51–M85) for Methanol-Capable Automotive Spark-Ignition Engines
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E355 Practice for Gas Chromatography Terms and Relationships
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
E1064 Test Method for Water in Organic Liquids by Coulometric Karl Fischer Titration
E1510 Practice for Installing Fused Silica Open Tubular Capillary Columns in Gas Chromatographs
3. Terminology
3.1 This test method makes reference to many common chromatographic procedures, terms, and relationships. Detailed definitions
can be found in Terminology D4175 and Practices D4626, E355, and E594.
3.2 Definitions:
3.2.1 analyte, n—a specific compound to be measured quantitatively in a mixture of compounds.
3.2.2 analytical column, n—a chromatographic column used to further separate a specific analyte from a mixture of compounds
which can coelute in the primary column.
3.2.3 analytical detector, n—a device used to quantify the compounds of interest after they elute from the analytical column.
3.2.4 fuel methanol (M99), n—methyl alcohol produced for the purpose of blending with gasoline to make a fuel for spark-ignition
internal combustion engines.
3.2.4.1 Discussion—
Fuel methanol is typically produced with 99 % by volume methyl alcohol.
3.2.5 gasoline, n—a volatile mixture of liquid hydrocarbons, generally containing small amounts of additives, suitable for use as
a fuel in spark-ignition internal combustion engines. D4814
3.2.6 heart-cut, n—in gas chromatography, a procedure in which the analyte in question is transferred from one column to a
different column, usually of the opposite polarity.
3.2.7 internal standard (IS), n—a high purity compound not present in the sample which is added to the sample and used to
calculate quantitatively the component of interest.
3.2.7.1 Discussion—
The internal standard is added in a constant amount to all calibration standards, see 7.4.2.1.
3.2.8 mass response factor (MRF), n—a constant of proportionality that converts area percent to mass percent.
3.2.9 methanol, n—methyl alcohol, the chemical compound CH OH.
3.2.10 methanol fuel blend, n—a fuel consisting primarily of a mixture of methanol with gasoline.
3.2.10.1 Discussion—
Typically methanol fuel blends are 70 % to 85 % by volume, identified as M70 to M85.
3.2.11 microfluidic device, n—a chromatographic switching valve constructed with micro channels, usually having five ports and
to which the columns, restrictors and auxiliary pressure devices are connected in order to carry out a heart-cut.
3.2.11.1 Discussion—
An auxiliary carrier gas is fed to the device which has two ports of entry such that switching the carrier gas from one port to the
other results in changing the direction of the flow of the primary column to either a restrictor or to the analytical column.
3.2.12 monitor detector, n—a device used to measure the elution of the analyte from the primary column.
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3.2.12.1 Discussion—
The monitor detector is used to determine the heart-cut time (see 6.1.1), that is, the time where the peak of interest begins and
where the peak of interest ends.
3.2.13 MXX, n—an abbreviation that represents a fuel consisting primarily of methanol (methyl alcohol) and hydrocarbons in
which ‘XX’ is the percent by volume of methanol in the blended fuel.
3.2.14 primary column, n—in chromatography, a device used to perform a primary separation of a mixture of compounds.
3.2.14.1 Discussion—
The primary column, also known as a monitor column, is used to separate the analyte of interest and to determine the start time
and the end time of the heart-cut.
4. Summary of Test Method
4.1 The sample is injected in to the gas chromatograph where components are separated in the primary column and subsequently
are eluted through the restrictor and detected by the monitor detector. The methanol is identified and the heart-cut window is
determined. The instrument settings are set to transfer the methanol from the primary column to the analytical column. A further
separation takes place in the analytical polar column suitable for the polarity of methanol. After elution from the secondary column,
the methanol is analyzed by the analytical detector. Fuel methanol (M99) is analyzed by the primary column only without the
execution of a heart-cut. Analysis is made in the monitor detector. In the case of fuel methanol (M99) the mass percent is
determined by difference.
5. Significance and Use
5.1 Methanol is used in blends with gasoline at levels of 70 % to 85 % by volume, as specified in Specification D5797. This test
method provides a quantitative approach to measure the methanol content in methanol fuel blends, from 10 % to 99 % by volume.
The usual concentration is 70 % to 85 % by volume (M70 to M85). The method is also used to analyze fuel methanol (M99) prior
to blending.
6. Apparatus
6.1 Gas Chromatograph, capable of operating at the conditions listed in Table 1 and Table 2. A heated flash vaporizing inlet, also
known as a split inlet, is designed to provide a linear sample split injection (for example, 500:1). This inlet is required for proper
sample introduction. Carrier gas controls shall be of adequate precision to provide reproducible column flows and split ratios in
order to maintain analytical integrity. Pressure and flow control devices used shall be designed to attain the linear velocity required
for optimum operation of the columns. Two separate flame ionization detectors are required for this test method. The use of one
detector alone is not possible as the setting of the heart-cut times will be difficult and the reliability of the exact cut time
determination may be compromised. Detectors should meet the sensitivity criteria of Practice E594.
TABLE 1 Conditions for Analysis of Methanol Fuel Blend—
Carrier Helium
Valve ON interval, min 2.37–2.60 3.25–3.36
Inlet temperature, °C 250
Split ratio 500/1
Primary column pressure, kPa 259.2
Primary column flow, mL/min 2
Analytical column pressure, kPa 190.1
Analytical column, flow, mL/min 3
Oven, initial T °C 50
Initial hold time, min 5.5
Oven temperature rate, °C /min 15
Final oven temperature, °C 190
Final hold time, min 3
Analytical FID, T °C 300
Hydrogen, mL/min 45
Air, mL/min 450
Make up, N mL/min 25
Monitor, FID, T °C 300
Hydrogen, mL/min 45
Air, mL/min 450
Make up, N mL/min 25
Volume injected, μL 0.2
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TABLE 2 Conditions for Analysis of Methanol Fuel Blend—
Carrier Hydrogen
Valve ON interval, min 1.42-1.52 1.94–2.06
Inlet temperature, °C 250
Split ratio 500/1
Primary column pressure, kPa 172.6
Primary column flow, mL/min 2.5
Analytical column pressure, kPa 120.7
Analytical column, flow, mL/min 3.5
Oven, initial T °C 50
Initial hold time, min 5.5
Oven temperature rate, °C /min 15
Final oven temperature, °C 190
Final hold time, min 3
Analytical FID, T °C 300
Hydrogen, mL/min 45
Air, mL/min 450
Make up, N mL/min 25
Monitor, FID, T °C 300
Hydrogen, mL/min 45
Air, mL/min 450
Make up, N mL/min 25
Volume injected, μL 0.2
6.1.1 A heart-cut is a technique which utilizes a switching device to which the following five (5) components are connected: (1)
a primary column, usually non-polar which spans from the inlet to the device, (2) an analytical column, usually a polar column,
that spans from the device to the analytical detector, (3) a restrictor or a tubing of small diameter which connects from the device
to a second detector whose function is to serve as the monitor detector, (4) an external pressure device which controls the pressure
at the point where the two columns coincide, and finally, (5), a solenoid that directs the pressure to the two points of the device.
By switching the applied pressure, the components eluting from the primary column can either be sent to the monitor detector or
to the analytical column where further separation occurs and thus the compounds of interest elute at the analytical detector.
6.2 Sample Introduction System—Automated liquid injection to the split inlet is required. Devices capable of 0.2 μL to 2.0 μL
injections is suitable.
6.3 Columns—The precision for this test method was developed utilizing fused silica open tubular columns with non-polar
polydimethylsiloxane bonded (cross-linked) phase coating and a polyethylene glycol coated fused silica column.
6.3.1 Primary Column—An open tubular column with a non-polar polydimethylsiloxane bonded (cross-linked) phase coating,
having 30 m by 0.25 mm with a 0.25 μm film thickness, is used as primary column. This column is installed from the split inlet
to the microfluidic device. Follow Practice E1510 for column installation at the split inlet. The column is also inserted to the proper
port of the microfluidic device with an appropriate ferrule. Follow the instructions of the manufacturer of the microfluidic device
when inserting the column and setting the ferrule to the column. Utmost care is required when making the connection of the ferrule
to the device in order not to crack the fused silica column.
6.3.2 Analytical Column—A second open tubular column, 30 m by 0.25 mm with a film thickness 0.25 μm, containing a
polyethylene glycol phase which is a polar phase. One end of this analytical column is inserted into the microfluidic device and
the opposite end is connected to the analytical detector. Observe the same precautions in making the connections as described in
6.3.1.
6.3.3 A balance restrictor is required; composed of inert deactivated fused silica whose dimensions provide the same flow
resistance as that of the analytical column while minimizing the holdup time of peaks eluting from the primary column to the
monitor detector. A typical sized restrictor will be of approximately 1 m in length and 0.1 mm internal diameter. It is connected
from the device to the monitor detector. This length is sufficient to accommodate the equivalent pneumatic resistance of the
analytical column. The dimensions of the restrictor facilitate the fast transfer of the eluents from the primary column so as to
provide negligible delay in reaching the monitor detector. Thus accurate cut times can be determined.
6.4 Microfluidic Device—The microfluidic device shall be treated to become inert in order to avoid adsorption of any components
in the sample. It shall be manufactured with extremely small volumes and grooves so as not to introduce peak broadening or dead
volumes. These devices are available from several manufacturers.
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6.5 Electronic Pressure Control—An electronic means of controlling the auxiliary pressure is required to cause the transfer of the
components from the primary column to the analytical column. This controller is connected to the microfluidic device through a
solenoid. The pressure controller must be capable of controlling pressures to within at least 0.069 kPa.
6.6 Solenoid—Device required to switch the direction of the flow from the restrictor point to the analytical column point. Typical
solenoids should be capable of executing more than one million cycles. The solenoid should be free of components that may
interfere with the analysis. When the solenoid is in the off position the flow of the primary column is sent to the monitor detector
(Fig. 1(a)). When the solenoid is in the on position, the flow of the primary column is sent to the analytical column and
subsequently to the analytical detector (Fig. 1(b)). A shunt restrictor is placed across the output of the solenoid which provides a
trickle of flow to the unswept section.
6.7 The gas chromatograph requires a means to program the pressures required for the transfer of components from the primary
to the analytical column as well as to control the inlet pressure during the analysis so as to perform backflush. It is essential that
the gas chromatograph be provided with accurate and reproducible oven temperature control. Control may be through hardware
or software of the gas chromatograph. In addition software is required to integrate the signals and perform internal standard and
or external standard calculations as required.
6.8 A data system is required to acquire data and to control the gas chromatograph’s operational variables. A data system is
required to perform calibrations and analysis in the internal standard mode. The data systems require that sample mass and internal
standard mass be entered. The calculation of response factors are described in Practice D4626.
7. Reagents and Materials
7.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform
to the specifications of the committee on Analytical Reagents of the American Chemical Society, where such specifications are
available. Consult Practice D4307 in the preparation of standard blends.
7.2 Carrier Gas—Helium or hydrogen having at least a minimum purity of 99.95 % can be used as carrier gas. Oxygen removal
systems and gas purifiers should be used. (Warning—Helium and hydrogen are compressed gases under high pressure).
(Warning—Hydrogen carrier gas requires additional safety considerations due to its high flammability and potential for
explosions. The use of hydrogen sensors for the detection of hydrogen leaks in the GC oven is highly recommended. These devices
should be capable of shutting the hydrogen flow to the gas chromatograph.)
FIG. 1 (a) Heart-cut System Flow to Monitor Detector
Reagent Chemicals, American Chemical Society Specifications,ACS Reagent Chemicals, Specifications and Procedures for Reagents and Standard-Grade Reference
Materials, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by the American Chemical Society, see Analar Standards for
Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC),
Rockville, MD.
D7920 − 21
FIG. 1 (b) Heart-cut System Flow to Analytical Detector (continued)
7.3 Detector Gases—Hydrogen, air, and nitrogen. The minimum purity of the gases used should be 99.95 % for the hydrogen and
nitrogen. The air should be hydrocarbon-free grade. Gas purifiers are recommended for the detector gases.
7.4 Standards for Calibration and Identification—Standards of all components to be analyzed are required for establishing
identification by retention time as well as for the preparation of calibration standards for quantitative measurements. These
materials shall be of known purity and free of the other components to be analyzed.
7.4.1 Methanol—(Warning—Flammable and may be harmful or fatal, if ingested or inhaled.) Minimum purity required of at least
99 % by volume and free of ethanol. It is recommended that the methanol used in calibration blends be stored over anhydrous
sodium sulfate. Water content of the methanol is required for the analysis. Refer to Test Method E1064.
7.4.2 Ethyl Acetate—(Warning—Flammable and may be harmful or fatal, if ingested or inhaled.) This compound is used as the
internal standard.
7.4.2.1 The internal standard is added in a constant amount to all calibration standards containing the analyte of interest. A plot
of the ratio of the area of analyte to internal standard versus the amount of analyte to internal standard yields a linear relationship.
The ensuing linear relationship is used to determine the concentration of the analyte in the sample.
7.4.3 Diluent—1,2-Dimethoxy ethane (>99 % and anhydrous), methanol free, is used for preparation of calibration standards. This
diluent shall be free of any compounds that coelute with methanol and ethyl acetate. (Warning—Flammable and may be harmful
or fatal, if ingested or inhaled.)
7.4.4 Gasoline—Used alternatively as a diluent and as verification of the absence of interfering compounds. The gasoline shall be
free of methanol and ethyl acetate. This can be accomplished by analyzing the diluent gasoline as a sample. Verify that the
chromatograms do not show the presence of any other component that coelutes with methanol or ethyl acetate.
7.4.5 Impurities in Fuel Methanol (M99)—The following additional chemicals are required to determine the response factors of
the impurities in the fuel methanol. These chemicals should be at least of the purity defined in 7.1: ethanol, acetone, isopropanol,
n-propanol, 2-butanol, isobutanol, and 1-butanol. (Warning—All of these chemicals are flammable and may be harmful or fatal,
if ingested or inhaled.)
7.5 Calibration Mixtures—There are two types of calibration procedures required. One set of calibration mixtures is used for the
analysis of fuel methanol (M99). The other calibration mixtures are used for the analysis of methanol in the methanol fuel blends.
7.5.1 Glassware—Volumetric flasks 25 mL and 100 mL class A are required. In addition, a 25 mL burette (tolerance 0.03 mL class
A TD) with 0.1 mL divisions is needed to prepare the calibration standards. A 10 mL burette (graduated in 0.05 mL) is required
to pipette the ethyl acetate.
D7920 − 21
7.5.2 Check for other impurities such as water. Water cannot be determined with sufficient accuracy by most GC methods and shall
be measured by other procedures such as Test Methods D1364 or E1064 and the result used to normalize the chromatographic
value. If any of the impurities found are components which are also present in the blend, determine their concentrations and make
the appropriate corrections.
7.6 Preparation of Standards for Methanol in Fuel Analysis—A guide for the preparation of the methanol fuel blend calibration
standards is provided in Table 3. The solutions are prepared in 25 mL volumetric flasks. Final volume is fixed to 25 mL by the
addition of 1,2-dimethoxyethane or gasoline (described in 7.4.4) as the diluent.
7.6.1 In a separate 25 mL volumetric flask, pipette 1.0 mL of ethyl acetate and dilute to the mark with the solutions prepared in
7.6. These solutions are used to determine the calibration curve.
7.7 Preparation of Standards for Fuel Methanol (M99):
7.7.1 Response Factor So
...