ASTM E3146-20

Standard Test Method for Determination of Carbonyls in Pyrolysis Bio-Oils by Potentiometric Titration

SIGNIFICANCE AND USE
5.1 While pyrolysis bio-oils are comprised of a large variety of compounds and chemical functional groups, quantification of carbonyl groups is especially important. Carbonyls are known to be responsible for the instability of bio-oil during both storage and processing. This method can be used to quantify the total carbonyl content of bio-oils.
SCOPE
1.1 This test method covers the determination of the carbonyl content of bio-oils derived from thermochemical decomposition of lignocellulosic biomass and their deoxygenated products. This method is used for determination of carbonyls between 0.5 and 8 mol/kg.  
1.2 Review the current and appropriate Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid procedures, and safety precautions and proper personal protective equipment.  
1.3 Units—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-Apr-2020
• ICS: 75.080 - Petroleum products in general
• Technical Committee: E48 - Bioenergy and Industrial Chemicals from Biomass
• Drafting Committee: E48.05 - Biomass Conversion

Relations

• Replaces: ASTM E3146-18a - Standard Test Method for Determination of Carbonyls in Pyrolysis Bio-Oils by Potentiometric Titration
• Effective Date: 01-May-2020
• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-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 D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• 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
• Refers: ASTM D6299-17a - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 15-Nov-2017
• Refers: ASTM D664-11a(2017) - Standard Test Method for Acid Number of Petroleum Products by Potentiometric Titration
• Effective Date: 01-May-2017
• Refers: ASTM D6299-17 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Jan-2017
• Refers: ASTM D6300-16 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Apr-2016
• Refers: ASTM D6300-15 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2015
• Refers: ASTM D6300-14ae1 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-May-2014
• Refers: ASTM D6300-13a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2013

Overview

ASTM E3146-20 is the internationally recognized standard test method for the determination of carbonyl content in pyrolysis bio-oils through potentiometric titration. Developed by ASTM International, this method plays a critical role in quantifying carbonyl groups (specifically aldehydes and ketones) in bio-oils obtained from the thermochemical decomposition of lignocellulosic biomass and their deoxygenated products. Accurate measurement of carbonyls is essential, as these compounds significantly impact the stability and performance of bio-oils during storage, handling, and processing.

Key Topics

• Bio-Oil Composition: Pyrolysis bio-oils are complex mixtures derived from the rapid thermal decomposition of biomass. Quantifying reactive carbonyl groups is crucial because their presence affects the chemical reactivity and long-term stability of the oil.
• Carbonyl Groups: Includes aldehydes and ketones, which are responsible for undesirable changes in bio-oil over time.
• Potentiometric Titration: This method involves the reaction of bio-oil samples with hydroxylamine hydrochloride, forming oximes, and the subsequent titration to determine total carbonyl content.
• Range of Determination: Applicable for samples with carbonyl content between 0.5 and 8 mol/kg, expressed in SI units.
• Interference and Precautions: Careful sample preparation, proper electrode calibration, and avoidance of interfering substances (e.g., certain alcohols, mineral acids) ensure accurate results.
• Quality Control: Regular analysis of validation samples and adherence to control charting practices maintain method precision and reliability.

Applications

• Bio-Oil Quality Assurance: Industrial producers and researchers rely on this standard to certify the quality of bio-oils intended for fuel, chemical feedstock, and other applications. Monitoring carbonyl content is vital for predicting shelf-life and processing performance.
• Process Development and Optimization: The test method assists in refining pyrolysis operations and upgrading strategies, enabling process engineers to evaluate the effectiveness of catalytic fast pyrolysis, hydrotreatment, or other deoxygenation techniques based on changes in carbonyl concentration.
• Research and Regulatory Compliance: Laboratories and regulatory bodies use the ASTM E3146-20 method for standardized reporting and to fulfill requirements for trade, safety, and environmental compliance related to bio-derived fuels and chemicals.
• Comparative Studies: The method provides a consistent basis for comparing carbonyl content across different bio-oil batches, feedstocks, and conversion technologies.

Related Standards

• ASTM D664: Acid Number of Petroleum Products by Potentiometric Titration - referenced for determining strong acid content and correcting for mineral acid interference.
• ASTM D1193: Specification for Reagent Water - specifies the quality of water used in analytical procedures.
• ASTM D6299: Statistical Quality Assurance and Control Charting Techniques - supports ongoing quality control for analytical labs.
• ASTM D6300: Determination of Precision and Bias Data - provides recommended procedures for validating the accuracy of testing methods.
• CEN/TR 17103:2017 and EN 16900:2017: European standards for the quality determination of fast pyrolysis bio-oils for engines and industrial boilers, respectively.

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Relevant keywords: ASTM E3146-20, carbonyl determination, pyrolysis bio-oil, potentiometric titration, biomass, biofuel quality, aldehydes, ketones, bio-oil analysis, standardized method, bioenergy standards, chemical stability, analytical chemistry, process optimization, quality control.

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: E3146 − 20
Standard Test Method for
Determination of Carbonyls in Pyrolysis Bio-Oils by
Potentiometric Titration
This standard is issued under the fixed designation E3146; 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 Measurement System Performance
D6300 Practice for Determination of Precision and Bias
1.1 This test method covers the determination of the carbo-
Data for Use in Test Methods for Petroleum Products,
nyl content of bio-oils derived from thermochemical decom-
Liquid Fuels, and Lubricants
position of lignocellulosic biomass and their deoxygenated
products. This method is used for determination of carbonyls 2.2 Other Standards
between 0.5 and 8 mol/kg. CEN/TR17103:2017 PetroleumandRelatedProducts-Fast
Pyrolysis Bio-oils for Stationary Internal Combustion
1.2 Review the current and appropriate Safety Data Sheets
Engines - Quality Determination
(SDS) for detailed information concerning toxicity, first aid
EN 16900:2017 Fast Pyrolysis Bio-oils for Industrial
procedures, and safety precautions and proper personal protec-
Boilers—Requirement and Test Methods
tive equipment.
1.3 Units—The values stated in SI units are to be regarded
3. Terminology
as standard. No other units of measurement are included in this
3.1 Definitions:
standard.
3.1.1 bio-oil, n—thecrudeliquidproductofconvertingsolid
1.4 This standard does not purport to address all of the
biomass into a liquid via fast pyrolysis or other thermochemi-
safety concerns, if any, associated with its use. It is the
cal conversion process.
responsibility of the user of this standard to establish appro-
3.1.2 carbonyl, n—the chemical functional group consisting
priate safety, health, and environmental practices and deter-
of a carbon-oxygen double bond, C=O.
mine the applicability of regulatory limitations prior to use.
3.1.2.1 Discussion—For this method, this includes all alde-
1.5 This international standard was developed in accor-
hydes and ketones; carboxylic acids, esters, and lactone groups
dance with internationally recognized principles on standard-
are not measured by this method.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
3.1.3 fast pyrolysis, n—pyrolysis conducted with rapid heat-
mendations issued by the World Trade Organization Technical
ing and short residence time; typically less than 10 s.
Barriers to Trade (TBT) Committee.
3.1.3.1 Discussion—Otherdefinitionsforfastpyrolysisstate
residence times of typically less than 10 s (1, 2), 5 s (CEN/TR
2. Referenced Documents
2 17103:2017, EN 16900:2017), and 1 s (3, 4).
2.1 ASTM Standards:
3.1.4 pyrolysis, n—chemical decomposition of organic ma-
D664 Test Method for Acid Number of Petroleum Products
terials by heating in the absence of oxygen.
by Potentiometric Titration
3.1.5 oxime, n—a group of compounds containing the
D1193 Specification for Reagent Water
chemical functional group >C=NOH, produced by the conden-
D6299 Practice for Applying Statistical Quality Assurance
sation of ketones or aldehydes with hydroxylamine.
and Control Charting Techniques to Evaluate Analytical
3.1.6 oximation reaction, n—reaction with or conversion
into an oxime.
This test method is under the jurisdiction of ASTM Committee E48 on
Bioenergy and Industrial Chemicals from Biomass and is the direct responsibility of
Subcommittee E48.05 on Biomass Conversion.
Current edition approved May 1, 2020. Published June 2020. Originally
approved in 2018. Last previous edition approved in 2018 as E3146 – 18a. DOI: Available from European Committee for Standardization (CEN), Avenue
10.1520/E3146-20. Marnix 17, B-1000, Brussels, Belgium, http://www.cen.eu.
2 4
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from British Standards Institution (BSI), 389 Chiswick High Rd.,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM London W4 4AL, U.K., http://www.bsigroup.com.
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parentheses refer to the list of references at the end of
the ASTM website. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3146 − 20
4. Summary of Test Method 7.4 Dry Block Heater with Magnetic Stirrer, capable of
maintainingatemperatureof80°C,forusewithmicroreaction
4.1 A bio-oil sample is dissolved in dimethylsulfoxide
vials. See Fig. 2.
(DMSO) and solutions are added containing hydroxylamine
7.4.1 A hot water bath with flat circular magnetic stirrer is
hydrochloride (NH OH·HCl) and triethanolamine (TEA). The
also acceptable.
mixtureissealed,stirred,andheatedto80 °Cfor2h.Carbonyl
compounds (aldehydes and ketones) react with NH OH·HCl 7.5 Potentiometric Titrator—Automatic titration systems
forming the corresponding oxime and liberating HCl. Liber- capable of adding fixed increments of titrant at fixed time
ated HCl is consumed by TEA, which drives the reaction intervals (monotonic) or variable titrant increments with elec-
forward.After the reaction, unconsumed TEAis titrated with a trode stability between increment additions (dynamic) with
standardized HCl titrant to determine the molar concentration endpoint seeking capabilities as prescribed in the method. At
of carbonyls in the sample. the very least, the automatic titration system shall meet the
performance and specification requirements as warranted by
5. Significance and Use
the manufacturer.
7.5.1 Amonotonic or dynamic mode of titrant addition shall
5.1 While pyrolysis bio-oils are comprised of a large variety
be used. During the titration, the speed and volume of the
of compounds and chemical functional groups, quantification
addition may vary depending on the rate of change of the
of carbonyl groups is especially important. Carbonyls are
system. The recommended minimum volume increment is
known to be responsible for the instability of bio-oil during
0.05 mL, and the recommended maximum volume increment
both storage and processing. This method can be used to
is 0.1 mL. A signal drift of 10 mV/min and endpoint recogni-
quantify the total carbonyl content of bio-oils.
tion set to last is recommended to ensure endpoint detection.
6. Interferences When using a monotonic titrant addition, the waiting time
between increment additions shall be sufficient to allow for
6.1 The selectivity of the method was tested by using
mixing and a stable electrode response. Wait at least 10 s
1-butanol, 1-pentanol, tertiary-butanol, 2-propanol, ethyl
between additions.
acetate, acetic acid, xylose, and glucose as model compounds,
representing alcohol, ester, carboxylic acid, and carbohydrates 7.6 Buret, capable of delivering titrant in 0.02 mL or larger
in the bio-oil. No interferences were seen for ethyl acetate or increments. The buret tip shall deliver titrant directly into the
acetic acid. Monosaccharides are measured using this method. titration vessel (immersed about 25 mm in liquid) without
Addition of alcohols causes interferences, but it is dependent exposure to the surrounding air.
on chain length. The reason is as yet undetermined but may be
7.7 Titration Stand, suitable for supporting the electrode,
related to solvent properties of the alcohol rather than reaction
stirrer, and buret.
with NH OH·HCl or TEA. Tests with primary, secondary, and
7.8 Sensing Electrode, standard pH, suitable for non-
tertiary butanol have shown the same effect.
aqueous titrations.
7. Apparatus
7.9 Reference Electrode—Silver/Silver Chloride (Ag/AgCl)
Reference Electrode, filled with 1M-3M LiCl in ethanol.
7.1 Analytical Balance, accurate to 0.0001 g.
7.10 Combination pH Electrodes—Sensing electrodes may
7.2 Micro Reaction Vial, borosilicate glass, cone shaped
have the Ag/AgCl reference electrode built into the same
inside with at least 5 mL capacity and PTFE lined caps. See
electrode body, which offers the convenience of working with
Fig. 1.
and maintaining only one electrode. A combination pH elec-
7.3 Triangular Magnetic Stirring Bar, PTFE lined and
trode designed for non-aqueous titrations of organic solvents is
suitable size for use with micro reaction vessels.
needed for titration of bio-oils. The combination pH electrode
shall have a sleeve junction on the reference compartment and
shall use an inert ethanol electrolyte, 1 to 3 mol/L (M) LiCl in
FIG. 1 Micro Reaction Vial with PTFE Lined Cap and Triangular
Magnetic Stirring Bar FIG. 2 Dry Block Heater
E3146 − 20
ethanol. Combination pH electrodes shall have the same or 8.11 Triethanolamine Solution (Solution B)—Add 17.4 mL
better response than a dual electrode system. They shall have a of triethanolamine to a 250 mLvolumetric flask, then dilute up
movable sleeve for easy rinsing and addition of electrolyte. to the mark with ethanol.
7.11 Titration Beaker, borosilicate glass or plastic beaker of 8.12 Hydrochloric Acid (HCl), concentrated (Warning—
suitable size for the titration. Toxic and corrosive).
7.12 Variable-Speed Mechanical Stirrer, a suitable type, 8.13 Hydrochloric Acid Solution—Prepare 0.1N solution by
equipped with either magnetic stirrer and stirring bars or adding 10 ml concentrated HCl and 1 L water.
propeller-type stirring paddle. The rate of stirring shall be
8.14 Carbonyl Validation Sample—4-
sufficient to produce vigorous agitation without spattering and
(Benzyloxy)benzaldehyde (4-BBA), ≥ 99 % purity.
without stirring air into the solution.
8.15 Commercially available solutions may be used in place
7.12.1 If an electrical stirring apparatus is used, it shall be
of laboratory preparations, provided the solutions have been
electrically correct and grounded so that connecting or discon-
certified as being equivalent.
necting the power to the motor will not produce a permanent
change in the instrument reading during the course of the 8.16 Alternate volumes of the solutions may be prepared,
titration. provided the final solution concentration is equivalent.
9. Sampling, Test Specimens, and Test Units
8. Reagents and Materials
9.1 Make sure the oil sample is at room temperature prior to
8.1 Purity of Reagents—Reagent grade chemicals shall be
withdrawing an aliquot for analysis. Bio-oil shall be thor-
used in all tests. Unless otherwise indicated, it is intended that
oughly homogenized to obtain a representative sample. Mix by
all reagents shall conform to the specifications of the commit-
shaking vigorously for at least 1 min, and visually inspect the
tee onAnalytical Reagents of theAmerican Chemical Society,
6 sample to ensure it is homogenous. Some bio-oils may require
where such specifications are available.
longer shaking times.
8.2 Purity of Water—Unless otherwise indicated, reference
9.2 Exposure to oxygen and heat shall be minimized to
to water shall be understood to mean reagent water that meets
prevent sample degradation prior to analysis.
the requirements of either Type I, II, or III of Specification
D1193.
10. Preparation of Apparatus
8.3 Ethanol, reagent grade (Warning—Flammable and
10.1 Prepare the titrator in accordance with the manufactur-
toxic).
er’s instructions. Any visible air bubbles in the buret tip shall
be eliminated prior to titration since this can lead to errors.
NOTE 1—Do not use ethanol containing 2-butanone or other ketone
denaturant as this will interfere with this method.
10.2 Preparation of Electrodes—When the combination pH
8.4 Lithium Chloride, LiCl.
electrode contains Ag/AgCl reference with an electrolyte,
which is not 1 to 3 mol/L (M) LiCl in ethanol, the electrolyte
8.5 Lithium Chloride Electrolyte—Prepare a 1M–3M solu-
shall be replaced. Drain the electrolyte from the electrode
tion of lithium chloride (LiCl) in ethanol.
(vacuum suction), wash away all the salt (if present) with
8.6 Commercial Aqueous pH 4 and pH 7 Buffer Solutions—
water, and then rinse with ethanol. Rinse several times with
These solutions shall be replaced at regular intervals consistent
LiCl electrolyte solution. Finally, replace the sleeve and fill the
with their stability or when contamination is suspected. Infor-
electrode with the LiCl electrolyte to the filling hole. When
mation relating to their stability is provided by the manufac-
refitting the sleeve, ensure that there will be a free flow of
turer.
electrolyte into the system.
8.7 Hydroxylamine Hydrochloride (NH OH·HCl), ≥ 99 %
10.3 Maintenance and Storage of Electrodes:
purity.
10.3.1 Follow the manufacturer’s instructions for storage
8.8 Hydroxylamine Hydrochloride Solution (Solution A)— and use of the electrode.
Add 7.7 g of hydroxylamine hydrochloride and 50 mLof water 10.3.2 Prior to each titration, the glass membrane needs to
to a 250 mL volumetric flask. Swirl until all solids are be rehydrated by soaking the prepared electrode in water for at
dissolved, then dilute up to the mark with ethanol. least 2 min. Rinse the electrode with water immediately prior
to use.
8.9 Sodium Carbonate (Primary Standard, Na CO ),
2 3
10.3.3 When not in use, immerse the lower half of the
≥ 99 % purity.
combination electrode in LiCl electrolyte. Do not allow elec-
8.10 Triethanolamine (TEA), ≥ 99 % purity.
trodes to remain immersed in a titrated sample solution for any
longer than it is necessary. While the electrodes are not
extremely fragile, handle them carefully at all times.
Reagent Chemicals, American Chemical Society Specifications, American
11. Calibration and Standardization
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
listed by the American Chemical Society, see Analar Standards for Laboratory
11.1 Calibration of Electrode:
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
11.1.1 Verify that the electrode is filled with 1 to 3 mol/L
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. (M) LiCl in ethanol solution (see 10.2).
E3146 − 20
11.1.2 Prepare the two buffer solutions, pH 7.0 and pH 4.0 12.2.2 Weigh 0.1 g to 0.15 g of 4-BBAintoa5mLreaction
by placing approximately 50 mLof each solution in individual vial. Record weight and add 0.5 mL DMSO and triangular stir
beakers. bar.
12.2.3 Add 2 mL of Solution A and dissolve sample.
11.1.3 Calibrate the electrode using the two buffer solutions
12.2.4 Add 2 mL of Solution B.
according to the manufacturer’s instructions. Immerse the
12.2.5 Cap tightly, place in preheated (80 °C) heater block
electrode in each buffer solution, adjust the stirring speed so
or water bath, and stir for 2 h.
thatadequatemixingoccurswithoutformingavortex,andwait
for the instrument reading.When the reading is complete, rinse
12.3 Sample Preparation:
the electrode in high purity water, wipe gently, and repeat the
12.3.1 Prepare each sample in duplicate.
measurements with the other buffer solution. Record the pH
12.3.2 Weight 0.1 g to 0.15 g of bio-oil sample intoa5mL
value with an accuracy of 0.01 and the temperature with an
reaction vial. Record weight and add 0.5 mL DMSO and
accuracy of 0.1 °C. The measured pH values should be within
triangular stir bar.
60.05 pH units of the buffer’s certified value.
12.3.3 Add 2 mL of Solution A and dissolve sample.
11.1.3.1 Verify that the calibration slope is between 0.95
12.3.4 Add 2 mL of Solution B.
and 1.02. An ideal pH glass electrode has a slope of 1.00
12.3.5 Cap tightly, place in preheated (80 °C) heater block
(100 % of the Nernst slope) and an electrode zero point of
or water bath, and stir for 2 h.
0 mV for pH 7 at 25 °C. In practice, the electrode zero point
12.4 For blanks, samples, and validation sample, the vol-
potential shal
...

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: E3146 − 18a E3146 − 20
Standard Test Method for
Determination of Carbonyls in Pyrolysis Bio-Oils by
Potentiometric Titration
This standard is issued under the fixed designation E3146; 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
1.1 This test method covers the determination of the carbonyl content of bio-oils derived from thermochemical decomposition
of lignocellulosic biomass and their deoxygenated products. This method is used for determination of carbonyls between 0.5 and
8 mol/kg.
1.2 Review the current and appropriate Safety Data Sheets (SDS) for detailed information concerning toxicity, first aid
procedures, and safety precautions and proper personal protective equipment.
1.3 Units—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.
2. Referenced Documents
2.1 ASTM Standards:
D664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration
D1193 Specification for Reagent Water
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
2.2 Other Standards
CEN/TR 17103:2017 Petroleum and related productsRelated Products - Fast pyrolysis bio-oils for stationary internal
combustion engines - quality determinationPyrolysis Bio-oils for Stationary Internal Combustion Engines - Quality
Determination
EN 16900:2017 Fast Pyrolysis bio-oilsBio-oils for industrial boilers—Requirement and test methodsIndustrial Boilers—
Requirement and Test Methods
3. Terminology
3.1 Definitions:
3.1.1 Bio-Oil,bio-oil, n—Thethe crude liquid product of converting solid biomass into a liquid via fast pyrolysis or other
thermochemical conversion process.
This test method is under the jurisdiction of ASTM Committee E48 on Bioenergy and Industrial Chemicals from Biomass and is the direct responsibility of Subcommittee
E48.05 on Biomass Conversion.
Current edition approved June 1, 2018May 1, 2020. Published January 2018June 2020. Originally approved in 2018. Last previous edition approved in 2018 as
E3146E3146 – 18a.–18. DOI: 10.1520/E3146–18A.10.1520/E3146-20.
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.
Available from European Committee for Standardization (CEN), Avenue Marnix 17, B-1000, Brussels, Belgium, http://www.cen.eu.
Available from British Standards Institution (BSI), 389 Chiswick High Rd., London W4 4AL, U.K., http://www.bsigroup.com.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E3146 − 20
3.1.2 Carbonyl,carbonyl, n—Thethe chemical functional group consisting of a carbon-oxygen double bond, C=O. For this
method, this includes all aldehydes and ketones; carboxylic acids, esters, and lactone groups are not measured by this method.
3.1.2.1 Discussion—
For this method, this includes all aldehydes and ketones; carboxylic acids, esters, and lactone groups are not measured by this
method.
3.1.3 fast pyrolysis, n—Pyrolysispyrolysis conducted with rapid heating and short residence time; typically less than 10
seconds.s.
3.1.3.1 Discussion—
– Other definitions for fast pyrolysis state residence times of typically less than 10 secondss (1, 2), 5 seconds (CEN standards,s
(CEN/TR 17103:2017, EN 16900:2017), and 1 seconds (23, 34).
3.1.4 pyrolysis, n—Chemicalchemical decomposition of organic materials by heating in the absence of oxygen.
3.1.5 oxime, n—a group of compounds containing the chemical functional group >C=NOH, produced by the condensation of
ketones or aldehydes with hydroxylamine.
3.1.6 oximation reaction, n—reaction with or conversion into an oxime.
4. Summary of Test Method
4.1 A bio-oil sample is dissolved in dimethylsulfoxide (DMSO) and solutions are added containing hydroxylamine
hydrochloride (NH OH·HCl) and triethanolamine (TEA). The mixture is sealed, stirred, and heated to 80 °C for 2 hours.h.
Carbonyl compounds (aldehydes and ketones) react with NH OH·HCl forming the corresponding oxime and liberating HCl.
Liberated HCl is consumed by TEA, which drives the reaction forward. After the reaction, unconsumed TEA is titrated with a
standardized HCl titrant to determine the molar concentration of carbonyls in the sample.
5. Significance and Use
5.1 While pyrolysis bio-oils are comprised of a large variety of compounds and chemical functional groups, quantification of
carbonyl groups is especially important. Carbonyls are known to be responsible for the instability of bio-oil during both storage
and processing. This method can be used to quantify the total carbonyl content of bio-oils.
6. Interferences
6.1 The selectivity of the method was tested by using 1-butanol, 1-pentanol, tertiary-butanol, 2-propanol, ethyl acetate, acetic
acid, xylose, and glucose as model compounds, representing alcohol, ester, carboxylic acid, and carbohydrates in the bio-oil. No
interferences were seen for ethyl acetate or acetic acid. Monosaccharides are measured using this method. Addition of alcohols
causes interferences, but it is dependent on chain length. The reason is as yet undetermined but may be related to solvent properties
of the alcohol rather than reaction with NH OH·HCl or TEA. Tests with primary, secondary, and tertiary butanol have shown the
same effect.
7. Apparatus
7.1 Analytical balance,Balance, accurate to 0.0001 g.
7.2 Micro Reaction Vial, borosilicate glass, cone shaped inside with at least 5 mL capacity and PTFE lined caps. See Fig. 1.
7.3 Triangular Magnetic Stirring Bar, PTFE lined and suitable size for use with micro reaction vessels.
7.4 Dry Block Heater with Magnetic Stirrer, capable of maintaining a temperature of 80 °C, for use with micro reaction vials.
See Fig. 2.
7.4.1 A hot water bath with flat circular magnetic stirrer is also acceptable.
7.5 Potentiometric Titrator—Automatic titration systems capable of adding fixed increments of titrant at fixed time intervals
(monotonic) or variable titrant increments with electrode stability between increment additions (dynamic) with endpoint seeking
capabilities as prescribed in the method. At the very least, the automatic titration system shall meet the performance and
specification requirements as warranted by the manufacturer.
7.5.1 A monotonic or dynamic mode of titrant addition shall be used. During the titration, the speed and volume of the addition
may vary depending on the rate of change of the system. The recommended minimum volume increment is 0.05 mL, and the
recommended maximum volume increment is 0.1 mL. A signal drift of 10 mV/min and endpoint recognition set to last is
The boldface numbers in parentheses refer to the list of references at the end of this standard.
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FIG. 1 Micro Reaction Vial with PTFE Lined Cap and Triangular Magnetic Stirring Bar
FIG. 2 Dry Block Heater
recommended to ensure endpoint detection. When using a monotonic titrant addition, the waiting time between increment additions
shall be sufficient to allow for mixing and a stable electrode response. Wait at least 10 s between additions.
7.6 Buret, capable of delivering titrant in 0.02 mL or larger increments. The buret tip shall deliver titrant directly into the
titration vessel (immersed about 25 mm in liquid) without exposure to the surrounding air.
7.7 Titration Stand, suitable for supporting the electrode, stirrer, and buret.
7.8 Sensing Electrode, standard pH, suitable for non-aqueous titrations.
7.9 Reference Electrode—Silver/Silver Chloride (Ag/AgCl) Reference Electrode, filled with 1M-3M LiCl in ethanol.
7.10 Combination pH Electrodes—Sensing electrodes may have the Ag/AgCl reference electrode built into the same electrode
body, which offers the convenience of working with and maintaining only one electrode. A combination pH electrode designed for
non-aqueous titrations of organic solvents is needed for titration of ethanol and ethanol blends. bio-oils. The combination pH
electrode shall have a sleeve junction on the reference compartment and shall use an inert ethanol electrolyte, 1 to 3 mol/L (M)
LiCl in ethanol. Combination pH electrodes shall have the same or better response than a dual electrode system. They shall have
a movable sleeve for easy rinsing and addition of electrolyte.
7.11 Titration Beaker, borosilicate glass or plastic beaker of suitable size for the titration.
7.12 Variable-Speed Mechanical Stirrer, a suitable type, equipped with either magnetic stirrer and stirring bars or propeller-type
stirring paddle. The rate of stirring shall be sufficient to produce vigorous agitation without spattering and without stirring air into
the solution.
7.12.1 If an electrical stirring apparatus is used, it shall be electrically correct and grounded so that connecting or disconnecting
the power to the motor will not produce a permanent change in the instrument reading during the course of the titration.
8. Reagents and Materials
8.1 Purity of Reagents—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
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such specifications are available. Other grades may be used provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
8.1.1 Commercially available solutions may be used in place of laboratory preparations provided the solutions have been
certified as being equivalent.
8.1.2 Alternate volumes of the solutions may be prepared, provided the final solution concentration is equivalent.
8.2 Purity of Water—Unless otherwise indicated, reference to water shall be understood to mean reagent water that meets the
requirements of either Type I, II, or III of Specification D1193.
8.3 Ethanol, reagent grade (Warning—Flammable and toxic).
NOTE 1—Do not use ethanol containing 2-butanone or other ketone denaturant as this will interfere with this method.
8.4 Lithium Chloride, LiCl.
8.5 Lithium Chloride Electrolyte—Prepare a 1M–3M solution of lithium chloride (LiCl) in ethanol.
8.6 Commercial Aqueous pH 4 and pH 7 Buffer Solutions—These solutions shall be replaced at regular intervals consistent with
their stability or when contamination is suspected. Information relating to their stability is provided by the manufacturer.
8.7 Hydroxylamine hydrochlorideHydrochloride (NH OH·HCl), ≥ 99%99 % purity.
8.8 Hydroxylamine hydrochloride solutionHydrochloride Solution (Solution A)—Add 7.7 g of hydroxylamine hydrochloride and
50 mL of water to a 250 mL volumetric flask. Swirl until all solids are dissolved, then dilute up to the mark with ethanol.
8.9 Sodium Carbonate (primary standard,(Primary Standard, Na CO ), ≥ 99% ≥ 99 % purity.
2 3
8.10 Triethanolamine (TEA), ≥ 99%99 % purity.
8.11 Triethanolamine solutionSolution (Solution B)—Add 17.4 mL of triethanolamine to a 250 mL volumetric flask, then dilute
up to the mark with ethanol.
8.12 Hydrochloric acidAcid (HCl), concentrated (Warning—Toxic and corrosive).
8.13 Hydrochloric acid solution—Acid Solution—Prepare 0.1N solution by adding 10 ml concentrated HCl and 1 L water.
8.14 4-(Benzyloxy)benzaldehyde (4-BBA), Carbonyl Validation Sample—4-(Benzyloxy)benzaldehyde (4-BBA), ≥ 99%99 %
purity.
8.15 Commercially available solutions may be used in place of laboratory preparations, provided the solutions have been
certified as being equivalent.
8.16 Alternate volumes of the solutions may be prepared, provided the final solution concentration is equivalent.
9. Sampling, Test Specimens, and Test Units
9.1 Make sure the oil sample is at room temperature prior to withdrawing an aliquot for analysis. Bio-oil shouldshall be
thoroughly homogenized to obtain a representative sample. Mix by shaking vigorously for at least 1 minute,min, and visually
inspect the sample to ensure it is homogenous. Some bio-oils may require longer shaking times.
9.2 Exposure to oxygen and heat shouldshall be minimized to prevent sample degradation prior to analysis.
10. Preparation of Apparatus
10.1 Prepare the titrator in accordance with the manufacturer’s instructions. Any visible air bubbles in the buret tip shall be
eliminated prior to titration since this can lead to errors.
10.2 Preparation of Electrodes—When the combination pH electrode contains Ag/AgCl reference with an electrolyte, which is
not 1 to 3 mol/L (M) LiCl in ethanol, the electrolyte shall be replaced. Drain the electrolyte from the electrode (vacuum suction),
wash away all the salt (if present) with water, and then rinse with ethanol. Rinse several times with LiCl electrolyte solution.
Finally, replace the sleeve and fill the electrode with the LiCl electrolyte to the filling hole. When refitting the sleeve, ensure that
there will be a free flow of electrolyte into the system.
10.3 Maintenance and Storage of Electrodes:
10.3.1 Follow the manufacturer’s instructions for storage and use of the electrode.
10.3.2 Prior to each titration, soak the the glass membrane needs to be rehydrated by soaking the prepared electrode in water
for at least 2 min. 2 min. Rinse the electrode with water immediately prior to use. The glass membrane needs to be rehydrated after
titration of non-aqueous solutions.
Reagent Chemicals, American Chemical Society Specifications, 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.
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10.3.3 When not in use, immerse the lower half of the combination electrode in LiCl electrolyte. Do not allow electrodes to
remain immersed in a titrated sample solution for any longer than it is necessary. While the electrodes are not extremely fragile,
handle them carefully at all times.
11. Calibration and Standardization
11.1 Calibration of Electrode:
11.1.1 Verify that the electrode is filled with 1 to 3 mol/L (M) LiCl in ethanol solution (see 10.2).
11.1.2 Prepare the two buffer solutions, pH 7.0 and pH 4.0 by placing approximately 50 mL of each solution in individual
beakers.
11.1.3 Calibrate the electrode using the two buffer solutions according to the manufacturer’s instructions. Immerse the electrode
in each buffer solution, adjust the stirring speed so that adequate mixing occurs without forming a vortex, and wait for the
instrument reading. When the reading is complete, rinse the electrode in high purity water, wipe gently, and repeat the
measurements with the other buffer solution. Record the pH value with an accuracy of 0.01 and the temperature with an accuracy
of 0.1 °C. The measured pH values should be within 60.05 pH units of the buffer’s certified value.
11.1.3.1 Verify that the calibration slope is between 0.95 and 1.02. An ideal pH glass electrode has a slope of 1.00 (100 % of
the Nernst slope) and an electrode zero point of 0 mV for pH 7 at 25 °C. In practice, the electrode zero point potential shall be
within 615 mV (corresponding to pH 6.75 to 7.25) and the slope shall be >0.95 (>56.2 mV per pH at 25 °C). The electrode zero
point and the electrode slope may change as a result of the aging of the glass membrane or contamination of the diaphragm. If
the electrode slope falls below 0.95, follow the electrode manufacturer’s instructions for electrode maintenance or replace the
electrode. The pH electrode shall be calibrated at regular intervals using (per manufacturer’s instructions) fresh buffer solutions.
11.1.3.2 The slope is automatically stored in the titrator.
11.1.3.3 The slope is not used for sample analysis, but rather, it provides information on the responsiveness of the electrode.
An electrode not meeting the stated criteria in 11.1.3.1 is not suitable to perform this method.
11.2 Standardization of HCl titrant:Titrant:
11.2.1 Weigh 0.10 to 0.15 g of sodium carbonate into titration beaker and record weight.
11.2.2 Add magnetic stir bar and 25 mL of water.
11.2.3 Titrate with HCl titrant using automatic titrator and record endpoint.
11.2.4 Prepare two additional sodium carbonate solutions to standardize the titrant a total of three times.
11.2.5 Use the Determine HCl molarity from each sodium carbonate titration using the calculation in 13.1three determinations
to . If the range of the three determinations (maximum-minimum) is ≤ 0.003, calculate the average concentration (mol/L) of the
HCl. The average of the titrant mol/L determinations should agree 6 0.0005 M. mol/L. If the range is > 0.003, the source of
imprecision shall be investigated and corrected.
12. Procedure
12.1 Preparation of Titration Blanks:
12.1.1 Blank A:
12.1.1.1 Prepare Blank A in triplicate.duplicate (two separate vials).
12.1.1.2 Add 0.5 mL DMSO to a 5 mL reaction vial and add triangular stir bar.
12.1.1.3 Add 2 mL of Solution A and 2 mL Solution B.
12.1.1.4 Cap tightly, place in preheated (80 °C) heater block or water bath, and stir for 2 hours.h.
12.2 Preparation of Carbonyl Validation Sample: Sample (4-BBA):
12.2.1 Pr
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