ASTM D6748-22

Standard Test Method for Determination of Potential Instability of Middle Distillate Fuels Caused by the Presence of Phenalenes and Phenalenones (Rapid Method by Portable Spectrophotometer)

SIGNIFICANCE AND USE
5.1 Storage stability depends on complex interactions. It varies with feedstock type and source, and the processing used. The rate of degradation may not change uniformly with temperature. Chemical reactions may lead to a change in color followed by the formation of soluble gums and insoluble sediments. Insoluble sediments may overload filters, and plug nozzles and injectors.  
5.2 This test method, which does not require the test sample to be heated, uses a portable apparatus and allows tests to be carried out on site or in the laboratory to give a result within 35 min.  
5.3 The potential beneficial effects of stability additives in fuels may not be recognized by this test method. Therefore, the actual storage stability of middle distillate fuels with stability additives may not be correctly indicated by these test results.  
5.4 The unstable reactive compounds (phenalenes and phenalenones) detected by this test method may be present in fuels containing catalytically cracked or straight run materials and can affect the potential instability of the fuel.  
5.5 If this test method is used by any party for a rapid assessment of stability, it is the responsibility of parties concerned to decide whether or not this procedure yields meaningful results.  
5.6 Interpretation of results and correlation with other test methods is given in Appendix X1.
SCOPE
1.1 This test method covers a procedure3 for the rapid determination of phenalenes and phenalenones in middle distillate fuels, including marine, automotive, heating, and gas turbine fuel such as those specified in Specifications D396, D975, D2069, and D2880. Phenalenes and phenalenones affect the potential instability of fuels, leading to fuel degradation products during storage, which may cause performance problems.  
1.2 This test method is applicable to both dyed and undyed fuels at all points in the distribution chain from refinery to end-user. It is not applicable to fuels containing residual oil. The portable apparatus allows the whole test to be conducted on site or in a laboratory and does not require the test sample to be heated.  
1.3 This test method is suitable for testing samples with a relative absorbance of up to 5.00 absorbance units (AU).
Note 1: The precision of the test method has been established on relative absorbance up to 1.00 AU. For relative absorbance above 1.00 AU the precision may not apply.  
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-2022
• ICS: 75.160.20 - Liquid fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.14 - Stability, Cleanliness and Compatibility of Liquid Fuels

Relations

• Refers: ASTM D975-23a - Standard Specification for Diesel Fuel
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D396-19a - Standard Specification for Fuel Oils
• Effective Date: 15-Dec-2019
• Refers: ASTM D396-19 - Standard Specification for Fuel Oils
• Effective Date: 01-May-2019
• Refers: ASTM D975-19 - Standard Specification for Diesel Fuel Oils
• Effective Date: 01-Feb-2019
• Refers: ASTM D975-18a - Standard Specification for Diesel Fuel Oils
• Effective Date: 01-Dec-2018
• Refers: ASTM D2880-18a - Standard Specification for Gas Turbine Fuel Oils
• Effective Date: 01-Oct-2018
• Refers: ASTM D396-18a - Standard Specification for Fuel Oils
• Effective Date: 01-Oct-2018
• Refers: ASTM D2880-18 - Standard Specification for Gas Turbine Fuel Oils
• Effective Date: 01-May-2018
• Refers: ASTM D396-18 - Standard Specification for Fuel Oils
• Effective Date: 01-May-2018
• Refers: ASTM D975-17a - Standard Specification for Diesel Fuel Oils
• Effective Date: 15-Dec-2017
• Refers: ASTM D396-17a - Standard Specification for Fuel Oils
• Effective Date: 01-Dec-2017
• Refers: ASTM D396-17 - Standard Specification for Fuel Oils
• Effective Date: 01-Jul-2017
• Refers: ASTM D975-17 - Standard Specification for Diesel Fuel Oils
• Effective Date: 01-May-2017

Overview

ASTM D6748-22, "Standard Test Method for Determination of Potential Instability of Middle Distillate Fuels Caused by the Presence of Phenalenes and Phenalenones (Rapid Method by Portable Spectrophotometer)," establishes a rapid and convenient procedure for assessing the potential storage instability of middle distillate fuels. This test method enables the detection and quantification of unstable reactive compounds-specifically, phenalenes and phenalenones-that can lead to degradation, soluble gums, and insoluble sediments during storage. Fuel instability can result in operational issues such as filter overloading, nozzle plugging, and injector fouling. ASTM D6748-22 allows for on-site or laboratory analysis in under 35 minutes and requires no heating of the sample, making it highly practical for field operations and fuel quality management.

Key Topics

• Phenalenes and Phenalenones Content: Measures the concentration of these key compounds, which are critical indicators of potential fuel instability.
• Middle Distillate Fuels Coverage: Applicable to marine, automotive, heating, and gas turbine fuels, including those specified in ASTM D396, D975, D2069, and D2880.
• On-site and Laboratory Use: Utilizes a portable spectrophotometer for flexible testing environments.
• Rapid Turnaround: Delivers results within 35 minutes, supporting timely decision-making across the fuel supply chain.
• Non-destructive and No-heat Method: Reduces sample handling complexity and safety risks compared to traditional heated tests.
• Influence of Additives: May not fully account for the stabilizing effects of fuel additives, highlighting the need for complementary test methods when stability additives are present.

Applications

ASTM D6748-22 is critical across various industries and scenarios where middle distillate fuel quality is essential to safe and efficient operation:

• Fuel Quality Assurance: Enables fuel producers, distributors, and end-users to rapidly determine the potential for degradation before storage or usage.
• Supply Chain Management: Suitable for use at any point in the distribution chain-from refineries and terminals to point-of-use-to monitor fuel stability and prevent performance issues downstream.
• On-site Diagnostics: The portable, simple-to-use equipment allows for immediate assessment of fuel samples in the field, avoiding delays associated with laboratory-based methods.
• Routine Monitoring and Compliance: Supports compliance with fuel specifications and helps prevent equipment downtime resulting from fuel instability-related deposits.
• Development of Fuel Additive Strategies: Informs decision-making regarding the need for additional stabilization, especially when dealing with fuels derived from high-risk feedstocks such as catalytically cracked or straight-run materials.

Related Standards

To ensure comprehensive fuel analysis and stability assessment, ASTM D6748-22 is commonly referenced alongside the following standards:

• ASTM D396: Specification for Fuel Oils
• ASTM D975: Specification for Diesel Fuel
• ASTM D2880: Specification for Gas Turbine Fuel Oils
• ASTM D4625: Test Method for Middle Distillate Fuel Storage Stability at 43°C (110°F)
• ASTM D6468: Test Method for High Temperature Stability of Middle Distillate Fuels
• ASTM D4057 and D4177: Practices for Manual and Automatic Sampling of Petroleum Products
• Def Stan 91-4 and Def Stan 05-50 Part 40: UK Ministry of Defence specifications for storage stability of diesel fuels

Practical Value

Implementing ASTM D6748-22 enhances fuel reliability, reduces operational interruptions, and empowers proactive maintenance and fuel management. Its rapid, portable, and non-destructive approach addresses the growing need for real-time fuel stability assessment in diverse operational contexts, ensuring compliance with international standards and minimizing the risks associated with storage-induced fuel deterioration.

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: D6748 − 22
Standard Test Method for
Determination of Potential Instability of Middle Distillate
Fuels Caused by the Presence of Phenalenes and
Phenalenones (Rapid Method by Portable
1,2
Spectrophotometer)
This standard is issued under the fixed designation D6748; 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* ization established in the Decision on Principles for the
3 Development of International Standards, Guides and Recom-
1.1 This test method covers a procedure for the rapid
mendations issued by the World Trade Organization Technical
determination of phenalenes and phenalenones in middle
Barriers to Trade (TBT) Committee.
distillate fuels, including marine, automotive, heating, and gas
turbine fuel such as those specified in Specifications D396,
2. Referenced Documents
D975, D2069, and D2880. Phenalenes and phenalenones affect
2.1 ASTM Standards:
the potential instability of fuels, leading to fuel degradation
D396 Specification for Fuel Oils
products during storage, which may cause performance prob-
D975 Specification for Diesel Fuel
lems.
D2069 Specification for Marine Fuels (Withdrawn 2003)
1.2 This test method is applicable to both dyed and undyed
D2880 Specification for Gas Turbine Fuel Oils
fuels at all points in the distribution chain from refinery to
D4057 Practice for Manual Sampling of Petroleum and
end-user. It is not applicable to fuels containing residual oil.
Petroleum Products
The portable apparatus allows the whole test to be conducted
D4175 Terminology Relating to Petroleum Products, Liquid
on site or in a laboratory and does not require the test sample
Fuels, and Lubricants
to be heated.
D4177 Practice for Automatic Sampling of Petroleum and
1.3 This test method is suitable for testing samples with a
Petroleum Products
relative absorbance of up to 5.00 absorbance units (AU). D4306 Practice for Aviation Fuel Sample Containers for
Tests Affected by Trace Contamination
NOTE 1—The precision of the test method has been established on
D4625 Test Method for Middle Distillate Fuel Storage
relativeabsorbanceupto1.00AU.Forrelativeabsorbanceabove1.00AU
the precision may not apply. Stability at 43 °C (110 °F)
D5854 Practice for Mixing and Handling of Liquid Samples
1.4 This standard does not purport to address all of the
of Petroleum and Petroleum Products
safety concerns, if any, associated with its use. It is the
D6468 Test Method for High Temperature Stability of
responsibility of the user of this standard to establish appro-
Middle Distillate Fuels
priate safety, health, and environmental practices and deter-
E131 Terminology Relating to Molecular Spectroscopy
mine the applicability of regulatory limitations prior to use.
E275 Practice for Describing and Measuring Performance of
1.5 This international standard was developed in accor-
Ultraviolet and Visible Spectrophotometers
dance with internationally recognized principles on standard-
2.2 Other Standards:
Def Stan 05-50 Methods for Testing Fuels and Lubricants
This test method is under the jurisdiction of ASTM Committee D02 on
and Associated Products, Part 40 — Storage Stability of
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Diesel Fuels
Subcommittee D02.14 on Stability, Cleanliness and Compatibility of Liquid Fuels.
Current edition approved Dec. 1, 2022. Published December 2022. Originally
approved in 2002. Last previous edition approved in 2017 as D6748 – 02a (2017).
DOI: 10.1520/D6748-22. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This test method is being jointly developed with the Institute of Petroleum contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
where it is designated IP 463. Standards volume information, refer to the standard’s Document Summary page on
This process is covered by US Patent 5,378,632. Interested parties are invited the ASTM website.
to submit information regarding the identification of an alternative(s) to this The last approved version of this historical standard is referenced on
patented item to ASTM International Headquarters. Your comments will receive www.astm.org.
careful consideration at a meeting of the responsible technical committee, which Available from United Kingdom Defence Standardization, Room 1138, Kenti-
you may attend. gern House, 65 Brown Street, Glasgow, G2 8EX. United Kingdom.
*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
D6748 − 22
DefStan91–4 Fuel,Naval,DistillateNATOCode:F76Joint absorbance of light is a measure of the concentration of the
Service, Designation DIESO F76 colored salts that are formed.
3. Terminology
5. Significance and Use
3.1 Definitions:
5.1 Storage stability depends on complex interactions. It
3.1.1 For definition of terms used in this test method, refer
varies with feedstock type and source, and the processing used.
to Terminology D4175.
The rate of degradation may not change uniformly with
3.1.2 For definitions of terms relating to absorption spec-
temperature. Chemical reactions may lead to a change in color
troscopy see Terminology E131. Terms of particular signifi-
followed by the formation of soluble gums and insoluble
cance are the following:
sediments. Insoluble sediments may overload filters, and plug
3.1.3 radiant energy, n—energy transmitted as electromag-
nozzles and injectors.
netic waves.
5.2 This test method, which does not require the test sample
3.1.4 radiant power P, n—the rate at which energy is
to be heated, uses a portable apparatus and allows tests to be
transported in a beam of radiant energy.
carried out on site or in the laboratory to give a result within
3.2 Definitions of Terms Specific to This Standard:
35 min.
3.2.1 absorbance, A, n—the logarithm to the base 10 of the
5.3 The potential beneficial effects of stability additives in
reciprocal of the transmittance, T. In symbols:
fuels may not be recognized by this test method.Therefore, the
A 5 log ~1/T!52log T (1)
actual storage stability of middle distillate fuels with stability
10 10
additives may not be correctly indicated by these test results.
where:
5.4 The unstable reactive compounds (phenalenes and phe-
T = transmittance as defined in 3.2.5.
nalenones) detected by this test method may be present in fuels
3.2.2 absorbance units (AU), n—units of relative absor-
containing catalytically cracked or straight run materials and
bance reported by the portable spectrophotometer.
can affect the potential instability of the fuel.
3.2.3 pathlength of test portion b, n—the distance in mm,
5.5 If this test method is used by any party for a rapid
measuredinthedirectionofpropagationofthebeamofradiant
assessment of stability, it is the responsibility of parties
energy, between the surfaces of the portion on which the
concerned to decide whether or not this procedure yields
radiant energy is incident and the surface of the test portion
meaningful results.
from which it emerges.
5.6 Interpretation of results and correlation with other test
3.2.4 relative absorbance, n—the difference between the
methods is given in Appendix X1.
absorbance (near infrared-visible band results) measured at the
two wavelengths, and reported in AU.
6. Apparatus
3.2.5 transmittance, T, n—the ratio of the radiant power
6.1 Spectrophotometer, double beam, capable of measuring
transmitted by the test portion in the test cuvette to the radiant
absorbance at one visible wavelength in the range 600 nm to
power transmitted by the Reagent 1 control in the cuvette.
800 nm and one near infrared wavelength in the range 800 nm
Expressed in the following equation.
to 850 nm with a spectral bandwidth of 10 nm 6 2 nm and an
T 5 P /P (2)
T R1
accuracy of 63 nm (see Fig. 1). The display shall have a
resolutionof0.01ofAU,andarepeatabilityofmeasurementof
where:
60.02 AU for ranges up to 1.00 AU. See Practice E275.
P = radiant power transmitted by the test portion, and
T
P = the radiant power transmitted by the Reagent 1
R1 NOTE 2—The two wavelengths used are proprietary and are not
control. adjustable.
6.1.1 Zero Adjustment, a facility shall be incorporated to
4. Summary of Test Method
allow the absorbance measured at the two individual wave-
4.1 A5 mLvolumeofmiddledistillatefuelismixedwithan
lengths to be set to zero when using Reagent 1 as a control.
equal volume of an immiscible reagent solution. A second
6.1.2 Absorbance Display, the relative absorbance, in AU,
reagent is then added, the new blend mixed and allowed to
shall be the instantaneous difference between the absorbance
settle for 30 min. for two phases to separate. The top reagent
measured at the two wavelengths. The peak wavelength
layer (darker) is then placed in the portable spectrophotometer
represents the absorption due to the colored indolylphenalene
and the relative absorbance of near infrared and visible light, at
salts which are formed, and the baseline wavelength is for
fixed single wavelengths, is measured instantaneously and
normalizing the result.
automatically, and reported in AU.
4.2 When mixed with the oil sample containing phenalenes,
the oxidizing Reagent 2 oxidizes the phenalenes to phenale-
The equipment, as
...

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: D6748 − 02a (Reapproved 2017) D6748 − 22
Standard Test Method for
Determination of Potential Instability of Middle Distillate
Fuels Caused by the Presence of Phenalenes and
Phenalenones (Rapid Method by Portable
1,2
Spectrophotometer)
This standard is issued under the fixed designation D6748; 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 a procedure for the rapid determination of phenalenes and phenalenones in middle distillate fuels,
including marine, automotive, heating, and gas turbine fuel such as those specified in Specifications D396, D975, D2069, and
D2880. Phenalenes and phenalenones affect the potential instability of fuels, leading to fuel degradation products during storage,
which may cause performance problems.
1.2 This test method is applicable to both dyed and undyed fuels at all points in the distribution chain from refinery to end-user.
It is not applicable to fuels containing residual oil. The portable apparatus allows the whole test to be conducted on site or in a
laboratory and does not require the test sample to be heated.
1.3 This test method is suitable for testing samples with a relative absorbance of up to 5.00 absorbance units (AU).
NOTE 1—The precision of the test method has been established on relative absorbance up to 1.00 AU. For relative absorbance above 1.00 AU the precision
may not apply.
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:
D396 Specification for Fuel Oils
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
D02.14 on on Stability, Cleanliness and Compatibility of Liquid Fuels.
Current edition approved Oct. 1, 2017Dec. 1, 2022. Published November 2017December 2022. Originally approved in 2002. Last previous edition approved in 20122017
as D6748D6748 – 02a (2017).–02a (2012). DOI: 10.1520/D6748-02AR17.10.1520/D6748-22.
This test method is being jointly developed with the Institute of Petroleum where it is designated IP 463.
This process is covered by US Patent 5,378,632. Interested parties are invited to submit information regarding the identification of an alternative(s) to this patented item
to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
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
D6748 − 22
D975 Specification for Diesel Fuel
D2069 Specification for Marine Fuels (Withdrawn 2003)
D2880 Specification for Gas Turbine Fuel Oils
D4057 Practice for Manual Sampling of Petroleum and Petroleum Products
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D4177 Practice for Automatic Sampling of Petroleum and Petroleum Products
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D4625 Test Method for Middle Distillate Fuel Storage Stability at 43 °C (110 °F)
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
D6468 Test Method for High Temperature Stability of Middle Distillate Fuels
E131 Terminology Relating to Molecular Spectroscopy
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
2.2 Other Standards:
Def Stan 05-50 Methods for Testing Fuels and Lubricants and Associated Products, Part 40 — Storage Stability of Diesel Fuels
Def Stan 91–4 Fuel, Naval, Distillate NATO Code: F76 Joint Service, Designation DIESO F76
3. Terminology
3.1 Definitions:
3.1.1 For definition of terms used in this test method, refer to Terminology D4175.
3.1.2 For definitions of terms relating to absorption spectroscopy see Terminology E131. Terms of particular significance are the
following:
3.1.3 radiant energy, n—energy transmitted as electromagnetic waves.
3.1.4 radiant power P, n—the rate at which energy is transported in a beam of radiant energy.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 absorbance, A, n—the logarithm to the base 10 of the reciprocal of the transmittance, T. In symbols:
A 5 log ~1/T! 52log T (1)
10 10
where:
T = transmittance as defined in 3.2.5.
3.2.2 absorbance units (AU), n—units of relative absorbance reported by the portable spectrophotometer.
3.2.3 pathlength of test portion b, n—the distance in mm, measured in the direction of propagation of the beam of radiant energy,
between the surfaces of the portion on which the radiant energy is incident and the surface of the test portion from which it
emerges.
3.2.4 relative absorbance, n—the difference between the absorbance (near infrared-visible band results) measured at the two
wavelengths, and reported in AU.
3.2.5 transmittance, T, n—the ratio of the radiant power transmitted by the test portion in the test cuvette to the radiant power
transmitted by the Reagent 1 control in the cuvette. Expressed in the following equation.
T 5 P /P (2)
T R1
where:
P = radiant power transmitted by the test portion, and
T
P = the radiant power transmitted by the Reagent 1 control.
R1
The last approved version of this historical standard is referenced on www.astm.org.
Available from United Kingdom Defence Standardization, Room 1138, Kentigern House, 65 Brown Street, Glasgow, G2 8EX. United Kingdom.
D6748 − 22
4. Summary of Test Method
4.1 A 5 mL volume of middle distillate fuel is mixed with an equal volume of an immiscible reagent solution. A second reagent
is then added, the new blend mixed and allowed to settle for 30 min. for two phases to separate. The top reagent layer (darker)
is then placed in the portable spectrophotometer and the relative absorbance of near infrared and visible light, at fixed single
wavelengths, is measured instantaneously and automatically, and reported in AU.
4.2 When mixed with the oil sample containing phenalenes, the oxidizing Reagent 2 oxidizes the phenalenes to phenalenones
which are subsequently converted to colored indolylphenalene salts by the acidic Reagent 1. The spectrophotometer measures the
absorbance of light caused by the colored salts while eliminating the effect of the initial color of the fuel. The absorbance of light
is a measure of the concentration of the colored salts that are formed.
5. Significance and Use
5.1 Storage stability depends on complex interactions. It varies with feedstock type and source, and the processing used. The rate
of degradation may not change uniformly with temperature. Chemical reactions may lead to a change in color followed by the
formation of soluble gums and insoluble sediments. Insoluble sediments may overload filters, and plug nozzles and injectors.
5.2 This test method, which does not require the test sample to be heated, uses a portable apparatus and allows tests to be carried
out on site or in the laboratory to give a result within 35 min.
5.3 The potential beneficial effects of stability additives in fuels may not be recognized by this test method. Therefore, the actual
storage stability of middle distillate fuels with stability additives may not be correctly indicated by these test results.
5.4 The unstable reactive compounds (phenalenes and phenalenones) detected by this test method may be present in fuels
containing catalytically cracked or straight run materials and can affect the potential instability of the fuel.
5.5 If this test method is used by any party for a rapid assessment of stability, it is the responsibility of parties concerned to decide
whether or not this procedure yields meaningful results.
5.6 Interpretation of results and correlation with other test methods is given in Appendix X1.
6. Apparatus
6.1 Spectrophotometer, double beam, capable of measuring absorbance at one visible wavelength in the range 600 nm to 800 nm
FIG. 1 Spectrophotometer
The equipment, as listed in RR:D02-1522 was used to develop the precision statement. The apparatus described in Section 6 and the reagents listed in Section 7 are both
supplied by Stanhope-Seta, Chertsey, Surrey KT16 8AP, United Kingdom. To date, no other equipment has demonstrated through ASTM interlaboratory testing the ability
to meet the precision of this test. This is not an endorsement or certification by ASTM International.
D6748 − 22
and one near infrared wavelength in the
...