ASTM D5441-21

Standard Test Method for Analysis of Methyl Tert-Butyl Ether (MTBE) by Gas Chromatography

SIGNIFICANCE AND USE
5.1 The presence of impurities in MTBE product can have a deleterious effect upon the value of MTBE as a gasoline additive. Oxygenate and olefin contents are of primary concern. This test method provides a knowledge of the composition of MTBE product. This is useful in the evaluation of process operations control, in the valuation of the product, and for regulatory purposes.  
5.2 Open tubular column gas chromatography with a flame ionization detector, used by the test method, is a technique that is sensitive to the contaminants commonly found in MTBE, and a technique that is widely used.
SCOPE
1.1 This test method covers the determination of the purity of methyl tert-butyl ether (MTBE) by gas chromatography. It also provides a procedure to measure impurities in MTBE such as C4 to C12 olefins, methyl, isopropyl and tert-butyl alcohols, methyl sec-butyl and methyl tert-amyl ethers, acetone, and methyl ethyl ketone. Impurities are determined to a minimum concentration of 0.02 % by mass.  
1.2 This test method is not applicable to the determination of MTBE in gasoline.  
1.3 Water cannot be determined by this test method and must be measured by a procedure such as Test Method D1364 and the result used to normalize the chromatographic values.  
1.4 A majority of the impurities in MTBE is resolved by the test method, however, some co-elution is encountered.  
1.5 This test method is inappropriate for impurities that boil at temperatures higher than 180 °C or for impurities that cause poor or no response in a flame ionization detector, such as water.  
1.6 The values stated in SI (metric) units of measurement are preferred and used throughout the standard.  
1.6.1 Exception—Alternate units, in common usage, are also provided to improve clarity and aid the user of this test method.  
1.7 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.  
1.8 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: 30-Nov-2021
• ICS: 71.080.60 - Alcohols. Ethers
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0L - Gas Chromatography Methods

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-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 D4626-95(2019) - Standard Practice for Calculation of Gas Chromatographic Response Factors
• 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 D4307-99(2015) - Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards
• Effective Date: 01-Oct-2015
• Refers: ASTM D3700-12 - Standard Practice for Obtaining LPG Samples Using a Floating Piston Cylinder
• Effective Date: 01-Nov-2012
• Refers: ASTM E594-96(2011) - Standard Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
• Effective Date: 01-Nov-2011
• Refers: ASTM D4057-06(2011) - Standard Practice for Manual Sampling of Petroleum and Petroleum Products
• Effective Date: 01-Jun-2011
• Refers: ASTM D4307-99(2010) - Standard Practice for Preparation of Liquid Blends for Use as Analytical Standards
• Effective Date: 01-May-2010
• Refers: ASTM D1364-02(2007) - Standard Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method)
• Effective Date: 01-Jun-2007
• Refers: ASTM E355-96(2007) - Standard Practice for Gas Chromatography Terms and Relationships
• Effective Date: 01-Mar-2007
• Refers: ASTM D3700-07 - Standard Practice for Obtaining LPG Samples Using a Floating Piston Cylinder
• Effective Date: 15-Feb-2007
• Refers: ASTM E594-96(2006) - Standard Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
• Effective Date: 01-Mar-2006
• Refers: ASTM D4626-95(2005) - Standard Practice for Calculation of Gas Chromatographic Response Factors
• Effective Date: 01-May-2005

Overview

ASTM D5441-21 is the established standard for the analysis of Methyl Tert-Butyl Ether (MTBE) purity and impurity profiling using gas chromatography. Developed by ASTM International, this test method is primarily used to determine the composition of MTBE, a critical oxygenate additive in gasoline. Accurate identification and quantification of impurities are essential because they can affect the value and performance of MTBE in fuel applications, influence processing control, and meet regulatory compliance.

This standard outlines procedures utilizing open tubular column gas chromatography with a flame ionization detector (FID), a sensitive and widely adopted technique suitable for detecting common contaminants in MTBE. The method enables the detection of impurities at concentrations as low as 0.02% by mass.

Key Topics

• Scope and Applicability

  • Determines the purity of MTBE and quantifies impurities such as C4 to C12 olefins, alcohols (methyl, isopropyl, tert-butyl), other ethers, acetone, and methyl ethyl ketone.
  • Not intended for the determination of MTBE in gasoline or for impurity compounds boiling above 180 °C or those not responsive to FID (e.g., water).

• Sampling and Preparation

  • MTBE samples are collected using standard practices to ensure representativeness and are preserved at low temperatures until analysis.
  • Apparatus setup and column conditioning adhere to best practices to maintain analytical integrity.

• Gas Chromatography Procedure

  • Utilizes fused silica open tubular columns with methyl silicone phases and helium as the carrier gas.
  • Employs a temperature-programmed analysis for optimal resolution of MTBE and its impurities.
  • Relies on response factors and normalization procedures for accurate quantitative results.

• Result Calculation and Reporting

  • Concentrations of detected components are corrected and normalized based on validated response factors.
  • Water content, which cannot be directly measured, must be determined by other ASTM methods and factored into the final calculation.
  • Reports component concentrations by mass (and optionally by volume) to two decimal places.

• Precision and Quality Control

  • The method specifies repeatability and reproducibility metrics for key components, supporting interlaboratory consistency.
  • Column and system suitability checks are integral to ensure reliable impurity separation.

Applications

ASTM D5441-21 is utilized across the petroleum, petrochemical, and fuel industries for:

• Product Quality Control

  • Ensuring that MTBE meets purity specifications for use as a gasoline additive.
  • Identifying and quantifying impurities to assess batch-to-batch consistency.

• Process Optimization

  • Monitoring and adjusting manufacturing processes based on impurity profiles.
  • Troubleshooting production deviations affecting MTBE composition.

• Regulatory Compliance

  • Supporting documentation required by regulatory bodies for fuel additives.
  • Providing a standardized approach to safeguard public and environmental interests.

• Research and Development

  • Characterizing new MTBE production technologies.
  • Enhancing formulations and fuel compositions.

Related Standards

Organizations referencing ASTM D5441-21 should consider the following related standards for comprehensive analysis and best practices:

• ASTM D1364 - Test Method for Water Content in Volatile Solvents
• ASTM D3700 - Practice for Obtaining LPG Samples
• ASTM D4057 - Practice for Manual Sampling of Petroleum Products
• ASTM D4175 - Terminology Relating to Petroleum Products and Liquid Fuels
• ASTM D4307 - Practice for Preparation of Liquid Blends for Analytical Standards
• ASTM D4626 - Practice for Calculation of Gas Chromatographic Response Factors
• ASTM E355 - Practice for Gas Chromatography Terms and Relationships
• ASTM E594 - Practice for Testing Flame Ionization Detectors

By following ASTM D5441-21 and the referenced methods, laboratories and producers can achieve high-precision MTBE analysis, ensuring product integrity and regulatory alignment. This standard plays a crucial role in quality assurance for gasoline additive manufacturers and the broader fuel and chemical industries.

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: D5441 − 21
Standard Test Method for
Analysis of Methyl Tert-Butyl Ether (MTBE) by Gas
Chromatography
This standard is issued under the fixed designation D5441; 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* mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers the determination of the purity
of methyl tert-butyl ether (MTBE) by gas chromatography. It
2. Referenced Documents
alsoprovidesaproceduretomeasureimpuritiesinMTBEsuch
2.1 ASTM Standards:
as C to C olefins, methyl, isopropyl and tert-butyl alcohols,
4 12
D1364 Test Method for Water in Volatile Solvents (Karl
methyl sec-butyl and methyl tert-amyl ethers, acetone, and
Fischer Reagent Titration Method) (Withdrawn 2021)
methyl ethyl ketone. Impurities are determined to a minimum
D3700 Practice for Obtaining LPG Samples Using a Float-
concentration of 0.02 % by mass.
ing Piston Cylinder
1.2 This test method is not applicable to the determination
D4057 Practice for Manual Sampling of Petroleum and
of MTBE in gasoline.
Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid
1.3 Water cannot be determined by this test method and
must be measured by a procedure such as Test Method D1364 Fuels, and Lubricants
D4307 Practice for Preparation of Liquid Blends for Use as
and the result used to normalize the chromatographic values.
Analytical Standards
1.4 Amajority of the impurities in MTBE is resolved by the
D4626 Practice for Calculation of Gas Chromatographic
test method, however, some co-elution is encountered.
Response Factors
1.5 This test method is inappropriate for impurities that boil
E355 Practice for Gas ChromatographyTerms and Relation-
at temperatures higher than 180 °C or for impurities that cause
ships
poor or no response in a flame ionization detector, such as
E594 Practice for Testing Flame Ionization Detectors Used
water.
in Gas or Supercritical Fluid Chromatography
1.6 The values stated in SI (metric) units of measurement
3. Terminology
are preferred and used throughout the standard.
3.1 Definitions—This test method makes reference to many
1.6.1 Exception—Alternate units, in common usage, are
common gas chromatographic procedures, terms, and relation-
also provided to improve clarity and aid the user of this test
ships. Detailed definitions of these and other terms used in this
method.
test method can be found in Practices E355 and E594, and
1.7 This standard does not purport to address all of the
Terminology D4175.
safety concerns, if any, associated with its use. It is the
3.2 Definitions of Terms Specific to This Standard:
responsibility of the user of this standard to establish appro-
3.2.1 C to C olefins, n—common olefin impurities in
priate safety, health, and environmental practices and deter-
4 12
MTBE are unreacted feedstock and dimers or trimers of feed
mine the applicability of regulatory limitations prior to use.
such as trimethylpentene or pentamethylheptene.
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4. Summary of Test Method
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- 4.1 Arepresentative aliquot of the MTBE product sample is
introduced into a gas chromatograph equipped with a methyl
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Subcommittee D02.04.0L on Gas Chromatography Methods. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 1, 2021. Published December 2021. Originally the ASTM website.
approved in 1993. Last previous edition approved in 2017 as D5441 – 98 (2017). The last approved version of this historical standard is referenced on
DOI: 10.1520/D5441-21. www.astm.org.
*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
D5441 − 21
silicone bonded phase fused silica open tubular column. duction. Carrier gas controls must be of adequate precision to
Helium carrier gas transports the vaporized aliquot through the provide reproducible column flows and split ratios in order to
column where the components are separated by the chromato- maintain analytical integrity. Pressure control devices and
graphic process. Components are sensed by a flame ionization gauges must be designed to attain the linear velocity required
detector as they elute from the column. in the column used (for example, if a 150 m column is used, a
pressure of approximately 550 kPa (80 psig) is required). A
4.2 The detector signal is processed by an electronic data
hydrogenflameionizationdetectorwithassociatedgascontrols
acquisition system or integrating computer. Each eluting com-
and electronics, designed for optimum response with open
ponent is identified by comparing its retention time to those
tubular columns, is required.
established by analyzing standards under identical conditions.
7.2 Sample Introduction—Manual or automatic liquid sy-
4.3 The concentration of each component in mass percent is
ringe sample injection to the splitting injector is employed.
determined by normalization of the peak areas after each peak
Devices capable of 0.1 µL to 0.5 µL injections are suitable. It
area has been corrected by a detector response multiplication
should be noted that inadequate splitter design, or poor
factor. The detector response factors are determined by ana-
injection technique, or both can result in poor resolution.
lyzing prepared standards with concentrations similar to those
Overloadingofthecolumncanalsocauselossofresolutionfor
encountered in the sample.
some components and, since overloaded peaks are skewed,
variation in retention times. Watch for any skewed peaks that
5. Significance and Use
indicate overloading during column evaluation. Observe the
5.1 The presence of impurities in MTBE product can have a
component size and where possible, avoid conditions leading
deleterious effect upon the value of MTBE as a gasoline
to this problem during the analyses.
additive. Oxygenate and olefin contents are of primary con-
7.3 Open Tubular Column —This test method utilizes a
cern. This test method provides a knowledge of the composi-
fused silica open tubular column with non-polar methyl sili-
tion of MTBE product. This is useful in the evaluation of
cone bonded (cross-linked) phase internal coating such as one
process operations control, in the valuation of the product, and
of the following:
for regulatory purposes.
Column length 50 m 100 m 150 m
5.2 Open tubular column gas chromatography with a flame
Film thickness 0.5 µm 0.5 µm 1.0 µm
ionization detector, used by the test method, is a technique that
Internal diameter 0.20 mm 0.25 mm 0.25 mm
is sensitive to the contaminants commonly found in MTBE,
Othercolumnswithequalorgreaterresolvingpowermaybe
and a technique that is widely used.
used. A minimum resolution between trans-2-pentene and
tert-butanol, and between cis-2-pentene and tert-butanol of 1.3
6. Interferences
is required. The 150 m column is expected to decrease the
6.1 Cyclopentane and 2,3-dimethylbutane have been ob-
likelihood of co-elution of impurities.
served to co-elute with MTBE. However, these are not com-
7.4 Electronic Data Acquisition System—Any data acquisi-
monly found impurities in MTBE.
tion and integration device used for quantification of these
analyses must meet or exceed these minimum requirements:
7. Apparatus
7.4.1 Capacity for at least 50 peaks per analysis,
7.1 Gas Chromatograph—Instrumentation capable of oper-
7.4.2 Normalized area percent calculations with response
ating at the conditions listed in Table 1. A heated flash
factors,
vaporizing injector designed to provide a linear sample split
7.4.3 Identification of individual components based on re-
injection (that is, 200:1) is required for proper sample intro-
tention time,
7.4.4 Noise and spike rejection capability,
TABLE 1 Typical Operating Conditions 7.4.5 Sampling rate for fast (<1 s) peaks,
7.4.6 Positive and negative sloping baseline correction,
Column Temperature Program
Column length 50 m 100 m 150 m
7.4.7 Peak detection sensitivity compensation for narrow
Initial temperature 40 °C 50 °C 60 °C
and broad peaks, and
Initial hold time 13 min 13 min 13 min
7.4.8 Non-resolved peaks separated by perpendicular drop
Program rate 10 °C ⁄min 10 °C ⁄min 10 °C ⁄min
Final temperature 180 °C 180 °C 180 °C
or tangential skimming as needed.
Final hold time 3 min 7 min 20 min
Injector
8. Reagents and Materials
Temperature 200 °C
Split ratio 200:1
8.1 Carrier Gas, helium, 99.99 % pure. (Warning—
Sample size 0.1 to 0.5 µL
Compressed gas under high pressure.)
Detector
Type flame ionization
8.2 Fuel Gas, hydrogen, 99.99 % pure. (Warning—
Temperature 250 °C
Fuel gas hydrogen ('30 mL/min) Extremely flammable gas under pressure.)
Oxidizing gas air ('300 mL/min)
Make-up gas nitrogen ('30 mL/min)
Carrier Gas
Petrocol DH series columns from Supelco, Inc., Bellefonte, PA were used to
Type helium
Average linear velocity 20 cm ⁄s to 24 cm ⁄s obtain the retention data and example chromatogram shown in this standard. Other
suitable columns are available commercially.
D5441 − 21
8.3 Oxidant, air, oil free. (Warning—Compressed gas un- 9. Sampling
der high pressure.)
9.1 MTBE can be sampled either in a floating piston
8.4 Make-Up Gas, nitrogen, 99.99 % pure. (Warning— cylinder or into an open container since vapor pressures less
Compressed gas under high pressure.)
than 70 kPa (10 psi) are expected.
9.1.1 Cylinder Sampling—Refer to Practice D3700 for in-
8.5 Reference Standards:
5,6
structionsontransferringarepresentativesamplefromasource
8.5.1 tert-Amyl methyl ether, (Warning—Flammable
into a floating piston cylinder.Add inert gas to the ballast side
liquid. Harmful if inhaled.)
of the piston to achieve a pressure of 310 kPa (45 psi) above
8.5.2 Butane, (Warning—Flammable liquid. Harmful if
the vapor pressure of the sample.
inhaled.)
9.1.2 Open Container Sampling—Refer to Practice D4057
8.5.3 tert-Butanol, (Warning—Flammable liquid. Harmful
for instructions on manual sampling from bulk storage into
if inhaled.)
7,6
open containers. Stopper container immediately after drawing
8.5.4 sec-Butyl methyl ether, (Warning—Flammable
sample.
liquid. Harmful if inhaled.)
8,6
8.5.5 4,4-Dimethyl-2-neopentyl-1-pentene, (Warning—
9.2 Preserve the sample by cooling to approximately 4 °C
Flammable liquid. Harmful if inhaled.)
and by maintaining that temperature until immediately prior to
8.5.6 Isobutylene, (Warning—Flammable liquid. Harmful
analysis.
if inhaled.)
9.3 Transfer an aliquot of the cooled sample into a pre-
8.5.7 Methanol, (Warning—See Note 1.)
cooled septum vial, then seal appropriately. Obtain the test
NOTE 1—Warning: Toxic Flammable Liquid. Harmful if inhaled or specimen for analysis directly from the sealed septum vial, for
ingested.
either manual or automatic syringe injection.
8,6
8.5.8 2-Methyl-2-butene, (Warning—Flammable liquid.
Harmful if inhaled.) 10. Preparation of Apparatus
9,6
8.5.9 Methyl tert-butyl ether, 99 + % pure, (Warning—
10.1 Installandconditioncolumninaccordancewithmanu-
Flammable liquid. Harmful if inhaled.)
facturer’s or supplier’s instructions. After conditioning, attach
8,6
8.5.10 2,2,4,6,6-Pentamethyl-3-heptene, (Warning—
column outlet to flame ionization detector inlet and check for
Flammable liquid. Harmful if inhaled.)
leaks throughout the system. When leaks are found, tighten or
8.5.11 n-Pentane, (Warning—Flammable liquid. Harmful
replace fittings before proceeding.
if inhaled.)
10.2 Adjust the carrier gas flow rate so that an average
8.5.12 cis-2-Pentene,(Warning—Flammableliquid.Harm-
linear velocity at the starting temperature of the run is between
ful if inhaled.)
21 and 24 cm/s, as determined in Eq 1. Flow rate adjustment is
8.5.13 trans-2-Pentene, (Warning—Flammable liquid.
made by raising or lowering the carrier gas pressure (head
Harmful if inhaled.)
pressure) to the injector. The following starting point pressures
8.5.14 2,4,4-Trimethyl-1-pentene, (Warning—Flammable
can be useful to adjust the carrier gas flow:
liquid. Harmful if inhaled.)
Column length 50 m 100 m 150 m
8.5.15 2,4,4-Trimethyl-2-pentene, (Warning—Flammable
Starting point pressure, kPa (psig) 262 (38) 275 (40) 552 (80)
liquid. Harmful if inhaled.)
10,6
10.2.1 Average Linear Gas Velocity:
8.5.16 1 % Contaminant Standard, contains 1.0 % of
some of the contaminants in MTBE, (Warning—Flammable
u 5 L/t (1)
ave m
liquid. Harmful if inhaled.)
10,6
where:
8.5.17 0.1 % Contaminant Standard, contains 0.1 % of
L = the length of the column in cm, and
some of the contaminants in MTBE, (Warning—Flammable
t = the retention time in seconds of methane.
m
liquid. Harmful if inhaled.)
10.3 Adjust the operating conditions of the gas chromato-
graph to conform to the list in Table 1. Turn on the detector,
ignite the flame, and allow the system to equilibrate.
The sole source of supply of the apparatus known to the committee at this time
is Sigma-Aldrich Chemical Company, Inc., Milwaukee, WI. A 96 % pure sample
10.4 When the method is first set up, ensure that the FID is
obtained from Sigma-Aldrich was the highest purity found.
not saturated. Plot the peak area versus MTBE concentration
If you are aware of alternative suppliers, please provide this information to
ASTM International Headquarters. Your comments will receive careful consider-
for prepared standards in the concentration range of interest. If
ation at a meeting of the responsible technical committee, which you may attend.
the plot is not linear, increase the split ratio, or use a less
The sole source of
...

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.
Designation: D5441 − 98 (Reapproved 2017) D5441 − 21
Standard Test Method for
Analysis of Methyl Tert-Butyl Ether (MTBE) by Gas
Chromatography
This standard is issued under the fixed designation D5441; 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 Scope*
1.1 This test method covers the determination of the purity of methyl tert-butyl ether (MTBE) by gas chromatography. It also
provides a procedure to measure impurities in MTBE such as C to C olefins, methyl, isopropyl and tert-butyl alcohols, methyl
4 12
sec-butyl and methyl tert-amyl ethers, acetone, and methyl ethyl ketone. Impurities are determined to a minimum concentration
of 0.02 mass %.0.02 % by mass.
1.2 This test method is not applicable to the determination of MTBE in gasoline.
1.3 Water cannot be determined by this test method and must be measured by a procedure such as Test Method D1364 and the
result used to normalize the chromatographic values.
1.4 A majority of the impurities in MTBE is resolved by the test method, however, some co-elution is encountered.
1.5 This test method is inappropriate for impurities that boil at temperatures higher than 180 °C or for impurities that cause poor
or no response in a flame ionization detector, such as water.
1.6 The values stated in SI (metric) units of measurement are preferred and used throughout the standard.
1.6.1 Exception—Alternate units, in common usage, are also provided to improve clarity and aid the user of this test method.
1.7 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.
1.8 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:
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 Oct. 1, 2017Dec. 1, 2021. Published November 2017December 2021. Originally approved in 1993. Last previous edition approved in 20132017
as D5441–98(2013).D5441 – 98 (2017). DOI: 10.1520/D5441-98R17.10.1520/D5441-21.
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
D5441 − 21
D1364 Test Method for Water in Volatile Solvents (Karl Fischer Reagent Titration Method) (Withdrawn 2021)
D3700 Practice for Obtaining LPG Samples Using a Floating Piston Cylinder
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
D4626 Practice for Calculation of Gas Chromatographic Response Factors
E355 Practice for Gas Chromatography Terms and Relationships
E594 Practice for Testing Flame Ionization Detectors Used in Gas or Supercritical Fluid Chromatography
3. Terminology
3.1 Definitions—This test method makes reference to many common gas chromatographic procedures, terms, and relationships.
Detailed definitions of these and other terms used in this test method can be found in Practices E355 and E594, and Terminology
D4175.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 C to C olefins—olefins, n—common olefin impurities in MTBE are unreacted feedstock and dimers or trimers of feed such
4 12
as trimethylpentene or pentamethylheptene.
4. Summary of Test Method
4.1 A representative aliquot of the MTBE product sample is introduced into a gas chromatograph equipped with a methyl silicone
bonded phase fused silica open tubular column. Helium carrier gas transports the vaporized aliquot through the column where the
components are separated by the chromatographic process. Components are sensed by a flame ionization detector as they elute
from the column.
4.2 The detector signal is processed by an electronic data acquisition system or integrating computer. Each eluting component is
identified by comparing its retention time to those established by analyzing standards under identical conditions.
4.3 The concentration of each component in mass percent is determined by normalization of the peak areas after each peak area
has been corrected by a detector response multiplication factor. The detector response factors are determined by analyzing prepared
standards with concentrations similar to those encountered in the sample.
5. Significance and Use
5.1 The presence of impurities in MTBE product can have a deleterious effect upon the value of MTBE as a gasoline additive.
Oxygenate and olefin contents are of primary concern. This test method provides a knowledge of the composition of MTBE
product. This is useful in the evaluation of process operations control, in the valuation of the product, and for regulatory purposes.
5.2 Open tubular column gas chromatography with a flame ionization detector, used by the test method, is a technique that is
sensitive to the contaminants commonly found in MTBE, and a technique that is widely used.
6. Interferences
6.1 Cyclopentane and 2,3-dimethylbutane have been observed to co-elute with MTBE. However, these are not commonly found
impurities in MTBE.
7. Apparatus
7.1 Gas Chromatograph—Instrumentation capable of operating at the conditions listed in Table 1. A heated flash vaporizing
injector designed to provide a linear sample split injection (that is, 200:1) is required for proper sample introduction. Carrier gas
controls must be of adequate precision to provide reproducible column flows and split ratios in order to maintain analytical
integrity. Pressure control devices and gauges must be designed to attain the linear velocity required in the column used (for
The last approved version of this historical standard is referenced on www.astm.org.
D5441 − 21
TABLE 1 Typical Operating Conditions
Column Temperature Program
Column length 50 m 100 m 150 m
Initial temperature 40 °C 50 °C 60 °C
Initial hold time 13 min 13 min 13 min
Program rate 10 °C ⁄min 10 °C ⁄min 10 °C ⁄min
Final temperature 180 °C 180 °C 180 °C
Final hold time 3 min 7 min 20 min
Injector
Temperature 200 °C
Split ratio 200:1
Sample size 0.1 to 0.5 μL
Detector
Type flame ionization
Temperature 250 °C
Fuel gas hydrogen ('30 mL/min)
Oxidizing gas air ('300 mL/min)
Make-up gas nitrogen ('30 mL/min)
Carrier Gas
Type helium
Average linear velocity 20 cm ⁄s to 24 cm ⁄s
example, if a 150 m column is used, a pressure of approximately 550 kPa (80 psig) is required). A hydrogen flame ionization
detector with associated gas controls and electronics, designed for optimum response with open tubular columns, is required.
7.2 Sample Introduction—Manual or automatic liquid syringe sample injection to the splitting injector is employed. Devices
capable of 0.1 μL to 0.5 μL injections are suitable. It should be noted that inadequate splitter design, or poor injection technique,
or both can result in poor resolution. Overloading of the column can also cause loss of resolution for some components and, since
overloaded peaks are skewed, variation in retention times. Watch for any skewed peaks that indicate overloading during column
evaluation. Observe the component size and where possible, avoid conditions leading to this problem during the analyses.
7.3 Open Tubular Column —This test method utilizes a fused silica open tubular column with non-polar methyl silicone bonded
(cross-linked) phase internal coating such as one of the following:
Column length 50 m 100 m 150 m
Film thickness 0.5 μm 0.5 μm 1.0 μm
Internal diameter 0.20 mm 0.25 mm 0.25 mm
Other columns with equal or greater resolving power may be used. A minimum resolution between trans-2-pentene and
tert-butanol, and between cis-2-pentene and tert-butanol of 1.3 is required. The 150 m column is expected to decrease the
likelihood of co-elution of impurities.
7.4 Electronic Data Acquisition System—Any data acquisition and integration device used for quantification of these analyses
must meet or exceed these minimum requirements:
7.4.1 Capacity for at least 50 peaks per analysis,
7.4.2 Normalized area percent calculations with response factors,
7.4.3 Identification of individual components based on retention time,
7.4.4 Noise and spike rejection capability,
7.4.5 Sampling rate for fast (<1 s) peaks,
7.4.6 Positive and negative sloping baseline correction,
7.4.7 Peak detection sensitivity compensation for narrow and broad peaks, and
Petrocol DH series columns from Supelco, Inc., Bellefonte, PA were used to obtain the retention data and example chromatogram shown in this standard. Other suitable
columns are available commercially.
D5441 − 21
7.4.8 Non-resolved peaks separated by perpendicular drop or tangential skimming as needed.
8. Reagents and Materials
8.1 Carrier Gas, helium, 99.99 % pure. (Warning—Compressed gas under high pressure.)
8.2 Fuel Gas, hydrogen, 99.99 % pure. (Warning—Extremely flammable gas under pressure.)
8.3 Oxidant, air, oil free. (Warning—Compressed gas under high pressure.)
8.4 Make-Up Gas, nitrogen, 99.99 % pure. (Warning—Compressed gas under high pressure.)
8.5 Reference Standards:
5,6
8.5.1 tert-Amyl methyl ether, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.2 Butane, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.3 tert-Butanol, (Warning—Flammable liquid. Harmful if inhaled.)
7,6
8.5.4 sec-Butyl methyl ether, (Warning—Flammable liquid. Harmful if inhaled.)
8,6
8.5.5 4,4-Dimethyl-2-neopentyl-1-pentene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.6 Isobutylene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.7 Methanol, (Warning—See Note 1.)
NOTE 1—Warning: Toxic Flammable Liquid. Harmful if inhaled or ingested.
8,6
8.5.8 2-Methyl-2-butene, (Warning—Flammable liquid. Harmful if inhaled.)
9,6
8.5.9 Methyl tert-butyl ether, 99 + % pure, (Warning—Flammable liquid. Harmful if inhaled.)
8,6
8.5.10 2,2,4,6,6-Pentamethyl-3-heptene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.11 n-Pentane, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.12 cis-2-Pentene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.13 trans-2-Pentene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.14 2,4,4-Trimethyl-1-pentene, (Warning—Flammable liquid. Harmful if inhaled.)
8.5.15 2,4,4-Trimethyl-2-pentene, (Warning—Flammable liquid. Harmful if inhaled.)
The sole source of supply of the apparatus known to the committee at this time is AldrichSigma-Aldrich Chemical Company, Inc., Milwaukee, WI. A 96 % pure sample
obtained from AldrichSigma-Aldrich was the highest purity found.
If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
The sole source of supply of the apparatus known to the committee at this time is Farcham Laboratories, Gainesville, FL.
The sole source of supply of the apparatus known to the committee at this time is Organic Technologies (formerly Wiley Organics), P.O. Box 640, 1245 S. 6th St.,
Coshocton, OH 43812.
The sole source of supply of the apparatus, HPLC grade MTBE, known to the committee at this time is from Aldrich Chemical Company, Inc., Milwaukee, WI.
D5441 − 21
10,6
8.5.16 1 % Contaminant Standard, contains 1.0 % of some of the contaminants in MTBE, (Warning—Flammable liquid.
Harmful if inhaled.)
10,6
8.5.17 0.1 % Contaminant Standard, contains 0.1 % of some of the contaminants in MTBE, (Warning—Flammable liquid.
Harmful if inhaled.)
9. Sampling
9.1 MTBE can be sampled either in a floating piston cylinder or into an open container since vapor pressures less than 70 kPa
(10 psi) are expected.
9.1.1 Cylinder Sampling—Refer to Practice D3700 for instructions on transferring a representative sample from a source into a
floating piston cylinder. Add inert gas to the ballast side of the piston to achieve a pressure of 310 kPa (45 psi) above the vapor
pressure of the sample.
9.1.2 Open Container Sampling—Refer to Practice D4057 for instructions on manual sampling from bulk storage into open
containers. Stopper container immediately after drawing sample.
9.2 Preserve the sample by cooling to approximately 4 °C and by maintaining that temperature until immediately prior to analysis.
9.3 Transfer an aliquot of the cooled sample into a precooled septum vial, then seal appropriately. Obtain the test specimen for
analysis directly from the sealed septum vial, for either manual or automatic syringe injection.
10. Preparation of Apparatus
10.1 Install and condition column in accordance with manufacturer’s or supplier’s instructions. After conditioning, attach column
outlet to flame ionization detector inlet and check for leaks throughout the system. When leaks are found, tighten or replace fittings
before proceeding.
10.2 Adjust the carrier gas flow rate so that an average linear velocity at the starting temperature of the run is between 21 and 24
cm/s, as determined in Eq 1. Flow rate adjustment is made by raising or lowering the carrier gas pressure (head pressure) to the
injector. The following starting point pressures can be useful to adjust the carrier gas flow:
Column length 50 m 100 m 150 m
Starting point pressure, kPa (psig) 262 (38) 275 (40) 552 (80)
10.2.1 Average
...