ASTM D8086-20

Standard Test Method for Determination of Methanol and Ethanol in Electrical Insulating Liquids of Petroleum Origin by Headspace (HS)-Gas Chromatography (GC) Using Mass Spectrometry (MS) or Flame Ionization Detection (FID)

SIGNIFICANCE AND USE
5.1 Methanol and ethanol are generated by the degradation of cellulosic materials used in the solid insulation systems of electrical equipment. More particularly, methanol comes from the depolymerization of cellulosic materials.3, 4, 5, 6  
5.2 Methanol and ethanol, which are soluble in an insulating liquid to an appreciable degree, will proportionally migrate to that liquid after being produced from the cellulose.  
5.3 High concentrations or unusual increases in the concentrations of methanol or ethanol, or both, in an insulating liquid may indicate cellulose degradation from aging or incipient fault conditions. Testing for these alcohols may be used to complement dissolved gas-in-oil analysis and furanic compounds as performed in accordance with Test Methods D3612 and D5837 respectively.
SCOPE
1.1 This test method describes the determination of by-products of cellulosic materials degradation found in electrical insulation systems that are immersed in insulating liquid. Such materials include paper, pressboard, wood and cotton materials. This test method allows the analysis of methanol and ethanol from the sample matrix by headspace GC-MS or GC-FID.  
1.2 This test method has been used to test for methanol and ethanol in mineral insulating liquids and less flammable electrical insulating liquids of mineral origin as defined in D3487 and D5222 respectively. Currently, this method is not a practical application for ester liquids.  
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: 30-Nov-2020
• ICS: 29.040.10 - Insulating oils
• Technical Committee: D27 - Electrical Insulating Liquids and Gases
• Drafting Committee: D27.03 - Analytical Tests

Relations

• Refers: ASTM D5837-15(2023) - Standard Test Method for Furanic Compounds in Electrical Insulating Liquids by High-Performance Liquid Chromatography (HPLC)
• Effective Date: 01-Dec-2023
• Refers: ASTM D923-15(2023) - Standard Practices for Sampling Electrical Insulating Liquids
• Effective Date: 01-Dec-2023
• Refers: ASTM D3612-02(2017) - Standard Test Method for Analysis of Gases Dissolved in Electrical Insulating Oil by Gas Chromatography
• Effective Date: 15-Nov-2017
• Refers: ASTM D3487-16e1 - Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus
• Effective Date: 15-Jun-2016
• Refers: ASTM D3487-16 - Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus
• Effective Date: 15-Jun-2016
• Refers: ASTM D5837-15 - Standard Test Method for Furanic Compounds in Electrical Insulating Liquids by High-Performance Liquid Chromatography (HPLC)
• Effective Date: 01-Oct-2015
• Refers: ASTM D923-15 - Standard Practices for Sampling Electrical Insulating Liquids
• Effective Date: 01-Oct-2015
• Refers: ASTM D5837-12 - Standard Test Method for Furanic Compounds in Electrical Insulating Liquids by High-Performance Liquid Chromatography (HPLC)
• Effective Date: 01-Feb-2012
• Refers: ASTM D3487-09 - Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus
• Effective Date: 01-Dec-2009
• Refers: ASTM D3612-02(2009) - Standard Test Method for Analysis of Gases Dissolved in Electrical Insulating Oil by Gas Chromatography
• Effective Date: 15-May-2009
• Refers: ASTM D3487-08 - Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus
• Effective Date: 01-Nov-2008
• Refers: ASTM D5222-08 - Standard Specification for High Fire-Point Mineral Electrical Insulating Oils
• Effective Date: 01-Jan-2008
• Refers: ASTM D923-07 - Standard Practices for Sampling Electrical Insulating Liquids
• Effective Date: 15-Jul-2007
• Refers: ASTM D3487-00(2006) - Standard Specification for Mineral Insulating Oil Used in Electrical Apparatus
• Effective Date: 01-Sep-2006
• Refers: ASTM D5837-99(2005) - Standard Test Method for Furanic Compounds in Electrical Insulating Liquids by High- Performance Liquid Chromatography (HPLC)
• Effective Date: 01-Oct-2005

Overview

ASTM D8086-20 standardizes a method for the determination of methanol and ethanol in electrical insulating liquids of petroleum origin using headspace gas chromatography (GC) coupled with either mass spectrometry (MS) or flame ionization detection (FID). These alcohols are important chemical markers, generated by the degradation of cellulosic insulation found in equipment such as transformers and electrical apparatus. Monitoring their concentrations helps assess the condition and safety of electrical insulation systems.

This test method is essential for utilities, laboratories, and manufacturers that need to ensure the long-term reliability and integrity of mineral oil-based electrical insulation systems.

Key Topics

• Methanol and Ethanol Detection: Focuses on the identification and quantification of methanol and ethanol, which are produced as by-products of cellulose decomposition in insulating materials.
• Headspace Gas Chromatography: Utilizes headspace (HS) extraction to enhance sensitivity by isolating volatile components from the liquid sample without direct injection, minimizing contamination and loss.
• Detection Systems: Offers analysis by GC coupled with either MS or FID, providing flexibility to laboratories with varying instrumentation.
• Significance for Asset Health: Elevated or increasing concentrations of alcohols are indicative of cellulose insulation aging, deterioration, or incipient fault conditions.
• Sample Handling: Emphasizes careful sample collection and handling using glass syringes and appropriate vials to avoid volatility losses of methanol and ethanol.
• Complement to Other Diagnostics: Can be used alongside dissolved gas analysis (ASTM D3612) and furanic compound analysis (ASTM D5837) for comprehensive transformer health monitoring.
• Calibration and Quality Assurance: Describes preparation of calibration standards and establishment of calibration curves to ensure result accuracy and reliability.
• Test Limitations: Designed for insulating liquids of petroleum origin (mineral oils and similar), not suitable for ester-based liquids.

Applications

• Power Transformer and Electrical Equipment Maintenance: Enables conditioning monitoring of cellulose-based insulation within transformers, circuit breakers, and other high-voltage apparatus.
• Aging Assessment: Methanol and ethanol levels help diagnose aging, degradation state, or failure risks in insulating systems.
• Quality Control in Manufacturing: Used by manufacturers of electrical insulating oils to ensure product purity and detect early signs of material degradation.
• Forensic Analysis: Supports root-cause investigations following insulation or equipment failure events.
• Routine Condition Monitoring: Forms part of preventive maintenance schedules in the power sector, aligning with transformer health assessment best practices.

Related Standards

• ASTM D3487: Specification for mineral insulating oil used in electrical apparatus, providing the base oil type for this test method.
• ASTM D3612: Test method for analysis of gases dissolved in electrical insulating oil by gas chromatography, often used in conjunction for fault diagnosis.
• ASTM D5222: Specification for high fire-point mineral electrical insulating oils relevant to certain less flammable liquid types.
• ASTM D5837: Test method for furanic compounds in electrical insulating liquids by high-performance liquid chromatography (HPLC), another key indicator of cellulose degradation.
• ASTM D923: Practices for sampling electrical insulating liquids, critical for ensuring sample integrity in alcohols analysis.

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Keywords: Methanol detection, ethanol testing, transformer oil, electrical insulating liquids, headspace gas chromatography, mass spectrometry, flame ionization detector, cellulose degradation, asset health monitoring, ASTM D8086-20.

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: D8086 − 20
Standard Test Method for
Determination of Methanol and Ethanol in Electrical
Insulating Liquids of Petroleum Origin by Headspace (HS)-
Gas Chromatography (GC) Using Mass Spectrometry (MS)
or Flame Ionization Detection (FID)
This standard is issued under the fixed designation D8086; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D3487Specification for Mineral Insulating Oil Used in
Electrical Apparatus
1.1 This test method describes the determination of by-
D3612Test Method for Analysis of Gases Dissolved in
products of cellulosic materials degradation found in electrical
Electrical Insulating Oil by Gas Chromatography
insulation systems that are immersed in insulating liquid. Such
D5222Specification for High Fire-Point Mineral Electrical
materials include paper, pressboard, wood and cotton materi-
Insulating Oils
als. This test method allows the analysis of methanol and
D5837Test Method for Furanic Compounds in Electrical
ethanol from the sample matrix by headspace GC-MS or
Insulating Liquids by High-Performance Liquid Chroma-
GC-FID.
tography (HPLC)
1.2 This test method has been used to test for methanol and
ethanol in mineral insulating liquids and less flammable
3. Terminology
electrical insulating liquids of mineral origin as defined in
D3487 and D5222 respectively. Currently, this method is not a
3.1 Definitions:
practical application for ester liquids.
3.1.1 extract ion mass spectrum, n—a record that shows a
1.3 The values stated in SI units are to be regarded as specific mass-to-charge ratio (m/z) extracted from a mass
standard. No other units of measurement are included in this spectrum.
standard.
3.1.2 mass spectrum, n—a record that shows the relative
1.4 This standard does not purport to address all of the
numberofionsofvariousmassthatareproducedwhenagiven
safety concerns, if any, associated with its use. It is the
substance is processed in a mass spectrometer.
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter-
4. Summary of Test Method
mine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accor- 4.1 Analysis of methanol (CH OH) and ethanol (C H OH)
3 2 5
dance with internationally recognized principles on standard- inelectricalinsulatingliquidsconsistsofbringinganinsulating
ization established in the Decision on Principles for the liquid sample in contact with a gas phase (headspace) in a
Development of International Standards, Guides and Recom- closedvessel.Thedissolvedspeciescontainedintheinsulating
mendations issued by the World Trade Organization Technical
liquid are then equilibrated between the two phases in contact
Barriers to Trade (TBT) Committee.
under controlled conditions (according to Henry’s law). At
equilibrium, the headspace is over-pressurized with a carrier
2. Referenced Documents
gas and then the content of a loop is filled by the depressur-
2.1 ASTM Standards:
ization of the headspace against the ambient atmospheric
D923Practices for Sampling Electrical Insulating Liquids
pressure (see Note 1).
NOTE 1—Other headspace principles may also be used but need to be
This test method is under the jurisdiction of ASTM Committee D27 on
verified and the analytical performance may be somewhat different than
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
listed.
mittee D27.03 on Analytical Tests.
CurrenteditionapprovedDec.1,2020.PublishedFebruary2021.DOI:10.1520/
4.2 The gases contained in the loop or in the syringe are
D8086-20.
2 introduced into a gas chromatograph.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
4.3 Methanolandethanolinthetestspecimenarequantified
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. using calibration curves.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8086 − 20
TABLE 1 Instrumental Conditions for MS Detection
5. Significance and Use
Headspace Sampler parameters
5.1 Methanol and ethanol are generated by the degradation
Test Specimen Loop volume 0.5 mL
of cellulosic materials used in the solid insulation systems of
Shaking Power Maximum Level
Temperatures Sample 90 °C
electrical equipment. More particularly, methanol comes from
3,4,5,6 Injection loop 150 °C
the depolymerization of cellulosic materials.
Transfer line 175 °C
Pressure Vial over-pressure 138 kPa
5.2 Methanolandethanol,whicharesolubleinaninsulating
Times Equilibration 40 min
liquid to an appreciable degree, will proportionally migrate to
Pressurization 0.2 min
that liquid after being produced from the cellulose. Loop fill 0.12 min
Loop equilibration 0.25 min
5.3 High concentrations or unusual increases in the concen-
Injection 6 min
trations of methanol or ethanol, or both, in an insulating liquid
Direct Injection Headspace System parameters
Test Specimen 2.5 mL
may indicate cellulose degradation from aging or incipient
Oven Temperature 90 °C
fault conditions. Testing for these alcohols may be used to
Oven Parameters Shaking for 40 min
complement dissolved gas-in-oil analysis and furanic com-
Syringe Temperature 100 °C
pounds as performed in accordance with Test Methods D3612 Gas Chromatograph parameters
He carrier gas flow 1.0 mL/min for 55 min
and D5837 respectively.
Injector Split/Splitless: 275 °C at 138 kPa
Split ratio 5 : 1
6. Interferences
Column 60m VF-624ms
0.250 mm dia., 1.4 µm film thickness
6.1 Vessels used for this test need to be prepared with
Oven Temp Initial 40 °C for 10 min
solvents containing no trace of methanol and ethanol. Ramp 1 40 to 275 °C at 20 °C/min
Hold 275 °C for 33.25 min
Additionally, solvents that can break down into these alcohols
Detector
must not be used.
Mass Spectrometer Ionization energy 70 eV
Interface at 280 °C
7. Apparatus m/z = 30-300 in TIC mode at 0.35
scans/s
7.1 Analytical balance capable of weighing to the nearest
0.0001g.
TABLE 2 Instrumental Conditions for FID Detection
7.2 Headspace sampler either equipped with an injection
loop and a transfer line or direct injection with gas-tight Headspace Sampler parameters
Test Specimen Loop volume 0.5 mL
syringe connected to the injection port of the gas chromato-
Shaking Power Maximum Level
graph. The sampler must be capable of equilibrating the
Temperatures Sample 90 °C
speciesofinterestinaspecifictime.Therequiredequilibration Injection loop 150 °C
Transfer line 175 °C
time can be minimized by mixing the sample during the
Pressure Vial over-pressure 138 kPa
equilibration period and this can be achieved by using a
Times Equilibration 40 min
Pressurization 0.2 min
sampler equipped with mechanical shaking. A direct injection
Loop fill 0.12 min
headspace vial system may also be used.
Loop equilibration 0.25 min
Injection 6 min
7.3 Gas chromatograph equipped with a mass spectrometer
Direct Injection Headspace System parameters
as described in Table 1 or equipped with FID detector as
Test Specimen 2.5 mL
described in Table 2 (see Note 2).
Oven Temperature 90 °C
NOTE 2—This method was developed with He as the carrier gas. Other
Oven Parameters Shaking for 40 min
carrier gases may also be used with this method but must be verified.
Syringe Temperature 100 °C
Analytical performance may be somewhat different than that listed in this Gas Chromatograph parameters
method. He carrier gas flow: 11 mL/min for 20 min
Injector Splitless 110 °C megabore direct
7.4 VF-624ms capillary column (60 m × 0.25 mm diameter
Column DB-624
with a film thickness of 1.4 µm) or DB-624 (60 m × 0.53 mm 60m×0.53mmID3µmfilm thickness
Oven Temp Initial 35 °C for 10 min
Ramp 1 35 to 250 °C at 5 °C/min
Hold 250 °C for 5 min
Jalbert, J., Gilbert, R., Tétreault, P., Morin, B., Lessard- Déziel, D., “Identifi-
Detector
cation of a chemical indicator of the rupture of 1,4-β-glycosidic bonds of cellulose
FID Temperature 300 °C
in an oil-impregnated insulating paper system,” Cellulose, 14:295-309, 2007.
4 Hydrogen 40 mL/min
Gilbert, R., Jalbert, J., Tétreault, P., Morin, B., and Denos, Y., “Kinetics of the
Air 400 mL/min
production of chain-end groups and methanol from the depolymerization of
He Makeup 5 mL/min
cellulose during the ageing of paper/oil systems,” Part 1: Standard wood kraft
insulation, Cellulose, 16: 327-338, 2009.
Gilbert, R., Jalbert, J., Duchesne, S., Tétreault, P., Morin, B., and Denos, Y.,
“Kinetics of the production of chain-end groups and methanol from the depolymer-
ization of cellulose during the ageing of paper/oil systems,” Part 2: Thermally-
ID with a film thickness of 3 µm) for the separation of
upgraded insulating papers, Cellulose, 17: 253-269, 2010.
methanol and ethanol. Other columns have been found to be
Jalbert, J., Rodriguez-Celis, E., Duchesne, S., Morin, B., Ryadi, M., and
suitable (see Note 3).
Gilbert, R., “Kinetics of the production of chain-end groups and methanol from the
NOTE3—Columnsthatgiveadequatepeakseparationmayalsobeused
depolymerization of cellulose during the ageing of paper/oil systems,” Part 3:
extension of the study under temperature conditions over 120 °C, Cellulose, 22: with this method but must be verified. Analytical performance may be
829-848, 2015. somewhat different than that listed in this method.
D8086 − 20
7.5 Headspace glass vials of 20 mL nominal capacity. The 7.8 Polytetrafluoroethylene (PTFE) faced butyl septa for
same batch of vials must be used for calibration and the headspace vials.
analysis of test specimens from samples (see Note 4).
7.9 30mLor50mLglasssyringesequippedwiththree-way
NOTE 4—Other vessel volumes may also be used but the analytical
plastic stopcocks for sampling.
performance would have to be verified and may be somewhat different
than that specified in the method.
7.10 The instrumental conditions for the analysis by
7.6 Crimping system, including crimp head and decapper
GC-MSaregiveninTable1andatotalionandextraction(m/z
head.
= 31) mass spectrums obtained under these conditions are
7.7 Perforated alumi
...