ASTM D8383-21

Standard Test Method for Methyl Hydrogen Content of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance Spectroscopy

SIGNIFICANCE AND USE
5.1 Methyl hydrogen content is a key characteristic of hydrocarbon lubricating oils and can affect a variety of properties of the oil including its boiling range, viscosity, low temperature flow, and oxidation stability.  
5.2 The NMR procedure does not require calibration standards of known methyl hydrogen content and is applicable to a wide range of hydrocarbon lubricating oils that are completely soluble in chloroform at ambient temperature.
SCOPE
1.1 This test method covers the determination of the total methyl hydrogen content of unadditized base stock (lubricating oils) hydrocarbon oils that are completely soluble in chloroform at ambient temperature using high-resolution nuclear magnetic resonance (NMR) spectrometers.  
1.2 The reported units are mol percent methyl hydrogen atoms. For pulse Fourier transform (FT) spectrometers, the detection limit is typically 0.1 % mol hydrogen atoms. The interim precision is applicable in the range 20.5 % to 38.7 % mol methyl hydrogen.  
1.3 This method is applicable to samples containing  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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. Specific precautionary statements are given in 7.2 and 7.3.  
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.04.0F - Absorption Spectroscopic Methods

Relations

• 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 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
• Refers: ASTM D6299-13e1 - Standard Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• Effective Date: 01-Oct-2013
• Refers: ASTM D6300-13 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 15-Jul-2013

Overview

ASTM D8383-21 - Standard Test Method for Methyl Hydrogen Content of Hydrocarbon Oils by High Resolution Nuclear Magnetic Resonance (NMR) Spectroscopy - provides an authoritative and precise method for determining the total methyl hydrogen content in unadditized base stock hydrocarbon oils. This test method is applicable to samples that are fully soluble in chloroform at ambient temperature and is vital for characterizing hydrocarbon lubricating oils.

Measuring methyl hydrogen content is essential because it influences several critical properties of lubricating oils, such as boiling range, viscosity, low-temperature flow, and oxidation stability. The use of high-resolution NMR spectroscopy allows for direct, calibration-free assessment of these molecular characteristics, streamlining testing for petroleum and lubricant manufacturers.

Key Topics

• Methyl hydrogen content determination: The method focuses on quantitative analysis of methyl hydrogens in hydrocarbon oils using 1H NMR spectroscopy.
• Applicable sample types: Unadditized base stock lubricating oils that are completely soluble in chloroform-d.
• NMR advantages:
  • No need for external calibration standards.
  • Applies to a broad variety of hydrocarbon oils.
• Units of measurement: Results are reported in mol percent methyl hydrogen atoms.
• Precision and detection limit:
  • Detection limit of typically 0.1% mol hydrogen atoms.
  • Interim measurement precision for samples within 20.5% to 38.7% mol methyl hydrogen.
• Safety and compliance:
  • Adheres to internationally recognized principles on standardization.
  • Users are responsible for implementing appropriate safety, health, and environmental practices.

Applications

ASTM D8383-21 is especially valuable in the petroleum, lubricants, and quality control sectors. Specific practical applications include:

• Product quality evaluation: Assessing and ensuring consistency in key properties of hydrocarbon lubricating oils during manufacturing and product development.
• Specification compliance: Verifying that base stocks meet required industry specifications for methyl hydrogen content, which is directly linked to performance attributes, such as low-temperature operation and oxidation resistance.
• Research and development: Enabling R&D teams to analyze and optimize formulations based on molecular composition.
• Statistical quality assurance: Integration with statistical quality control methods for continuous process monitoring as referenced by ASTM D6299.

This standard enhances laboratory efficiency by minimizing the need for reference calibration and leveraging the quantitative nature of NMR spectroscopy to deliver fast, trustworthy results.

Related Standards

The following ASTM standards are frequently used in conjunction with or as references for ASTM D8383-21:

• ASTM D4057: Practice for Manual Sampling of Petroleum and Petroleum Products
• ASTM D6299: Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measurement System Performance
• ASTM D6300: Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• ASTM E386: (Withdrawn) Practice for Data Presentation Relating to High-Resolution NMR Spectroscopy

Summary

Adopting ASTM D8383-21 increases the accuracy and reliability of methyl hydrogen content measurements in hydrocarbon oils, supporting quality control, regulatory compliance, and product optimization efforts within the petroleum and lubricants industries. As a globally recognized method, it leverages high-resolution NMR spectroscopy for direct, calibration-free, and reproducible quantification, ensuring that oil manufacturers and laboratories stay at the leading edge of analytical testing and industry standards compliance.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D8383 − 21
Standard Test Method for
Methyl Hydrogen Content of Hydrocarbon Oils by High
Resolution Nuclear Magnetic Resonance Spectroscopy
This standard is issued under the fixed designation D8383; 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 D5292Test Method for Aromatic Carbon Contents of Hy-
drocarbon Oils by High ResolutionNuclear Magnetic
1.1 This test method covers the determination of the total
Resonance Spectroscopy (Withdrawn 2018)
methylhydrogencontentofunadditizedbasestock(lubricating
D6299Practice for Applying Statistical Quality Assurance
oils) hydrocarbon oils that are completely soluble in chloro-
and Control Charting Techniques to Evaluate Analytical
form at ambient temperature using high-resolution nuclear
Measurement System Performance
magnetic resonance (NMR) spectrometers.
D6300Practice for Determination of Precision and Bias
1.2 The reported units are mol percent methyl hydrogen
Data for Use in Test Methods for Petroleum Products,
atoms. For pulse Fourier transform (FT) spectrometers, the
Liquid Fuels, and Lubricants
detection limit is typically 0.1% mol hydrogen atoms. The
E386Practice for Data Presentation Relating to High-
interim precision is applicable in the range 20.5% to 38.7%
Resolution Nuclear Magnetic Resonance (NMR) Spec-
mol methyl hydrogen.
troscopy (Withdrawn 2015)
1.3 Thismethodisapplicabletosamplescontaining<0.1%
3. Terminology
mol olefinic hydrogens.
3.1 Definitions of Terms Specific to This Standard:
1.4 The values stated in SI units are to be regarded as
3.1.1 methyl hydrogen, n—H-NMR signal in the spectral
standard. No other units of measurement are included in this
region of 0.1ppm to the valley at approximately 1ppm as a
standard.
percentage of total hydrogens.
1.5 This standard does not purport to address all of the
3.1.1.1 Discussion—NMR spectrometers meeting vendor
safety concerns, if any, associated with its use. It is the
specifications for signal to noise ratio and resolution are
responsibility of the user of this standard to establish appro-
acceptable as defined in 6.1.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. 3.2 Definitions of chemical shift (reported in parts per
million (ppm)), internal reference, spectral width, and other
Specific precautionary statements are given in 7.2 and 7.3.
1.6 This international standard was developed in accor- NMR terminology used in this test method can be found in
Practice E386 or any suitable vendor recommended method to
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the convert to ppm.
Development of International Standards, Guides and Recom-
3.3 Chloroform-d refers to chloroform solvent in which
mendations issued by the World Trade Organization Technical
hydrogen is replaced by deuterium, the heavier isotope of
Barriers to Trade (TBT) Committee.
hydrogen. Chloroform-d is available from a variety of chemi-
cal and isotope suppliers (Test Method D5292).
2. Referenced Documents
2.1 ASTM Standards:
4. Summary of Test Method
D4057Practice for Manual Sampling of Petroleum and
4.1 Hydrogen ( H) nuclear magnetic resonance (NMR)
Petroleum Products
spectra are obtained on solutions of the sample in
chloroform-d, using a pulse FT high-resolution NMR spec-
This test method is under the jurisdiction of ASTM Committee D02 on
trometer.Tetramethylsilaneispreferredasaninternalreference
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.04.0F on Absorption Spectroscopic Methods. in these solvents for assigning the 0.0parts per million (ppm)
Current edition approved April 1, 2021. Published April 2021. DOI: 10.1520/
chemical shift position in the H spectra.
D8383-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D8383 − 21
4.2 Themethylhydrogencontentofthesampleismeasured used, provided it is first ascertained that the reagent is of
by comparing the total integral for the H NMR spectrum of sufficiently high purity to permit its use.
the 0.1ppm to about 1ppm chemical shift region with the 1
7.2 Chloroform-d—For H NMR, chloroform-d must con-
integral from 0.1ppm to about 8ppm. Integration is for all the
tain less than 0.2% by volume residual chloroform. Care must
signal peaks greater than 0.1%, excluding the solvent peaks.
be taken not to contaminate the solvent with water and other
4.3 The integral of the hydrogen content must be corrected extraneousmaterials.(Warning—Healthhazard.Highlytoxic.
for the NMR absorption line due to residual chloroform
Cancer suspect agent. Can be fatal when swallowed and
(7.25ppm chemical shift) in the predominantly chloroform-d harmful when inhaled. Can produce toxic vapors when
solvent.
burned.)
7.3 Tetramethylsilane, American Chemical Society (ACS)
5. Significance and Use
1 13
reagent internal chemical shift reference for H and C NMR
5.1 Methyl hydrogen content is a key characteristic of
spectra. (Warning—Flammable liquid.)
hydrocarbon lubricating oils and can affect a variety of
7.4 Pristane 2,6,10,14-Tetramethylpentadecane, ≥98 %
properties of the oil including its boiling range, viscosity, low
mass purity. (Warning—Flammable liquid.)
temperature flow, and oxidation stability.
5.2 The NMR procedure does not require calibration stan-
8. Sampling
dards of known methyl hydrogen content and is applicable to
8.1 It is assumed that a representative sample acquired by a
a wide range of hydrocarbon lubricating oils that are com-
procedureofPracticeD4057orequivalenthasbeenreceivedin
pletely soluble in chloroform at ambient temperature.
the laboratory. If the test is not to be conducted immediately
6. Apparatus
upon receipt of the sample, store in a cool place until needed.
6.1 High-Resolution Nuclear Magnetic Resonance
8.2 A minimum of approximately 10mL of sample is
Spectrometer—Ahigh-resolution pulse Fourier transform (FT)
required for this test method. This should allow duplicate
NMR spectrometer capable of being operated according to the
determinations, if desired.
conditions in Table 1 and of producing peaks having widths
8.3 All samples must be homogeneous prior to subsam-
less than the frequency ranges of the majority of chemical
pling. If any suspended particles present are attributable to
shifts and coupling constants for the measured nucleus and
foreign matter such as rust, filter a portion of the sample to be
yielding the required values on the specified quality control
tested through a small plug of glass wool, contained in a clean
standard may be used. Precision was developed using
small funnel, into a clean and dry vial, or NMR sample tube
400MHz and 500MHz spectrometers.
containing chloroform-d.
6.2 NMR Tubes—Usually a 5mm outside diameter tube
8.4 If the sample contains waxy materials, heat the sample
compatible with the configuration pulse FT spectrometer.
in the container to approximately 60°C and mix with a
high-shear mixer prior to sampling. It may be necessary to
7. Reagents and Materials
transfer a portion of the sample to an NMR tube containing
7.1 Purity of Reagents—Reagent grade chemicals shall be
chloroform-d by means of a pipet which has been heated to
used in all tests. Unless otherwise indicated, it is intended that
approximately 60°C to maintain the homogeneity of the
all reagents shall conform to the specifications of the Commit-
sample.
tee onAnalytical Reagents of theAmerican Chemical Society,
8.5 For a valid test result, samples must be completely
where such specifications are available. Other grades may be
solubleinchloroform-d.Checktoensurethatthefinalsolution
is homogeneous and free of undissolved particles.
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
Standard-Grade Reference Materials, American Chemical Society, Washington,
9. Procedure
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
9.1 The procedure is described in this section for determin-
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
ing the hydrogen methyl content of lubricating hydrocarbons.
copeial Convention, Inc. (USPC), Rockville, MD.
TABLE 1 Typical Sample and Instrument Conditions for Pulse Fourier Transform Measurements of H NMR Spectra Used to Obtain
Precision
Solvent Chloroform-d
Sample concentration Must be optimized for the instrument in use but may be as high as 5 % v/v
Sample temperature Instrument ambient
Internal lock Deuterium (when chloroform-d is used for H NMR)
Sample spinning rate As recommended by manufacturer, typically 10 Hz to 20 Hz
Pulse flip angle Approximately 45°
Sequence delay time H NMR 15 s
Memory size for acquisition Choose to give a minimum digitizing rate of 0.5 Hz ⁄point for H. Use a minimum acquisition time of 3 s to 4 s.
Spectral width At least 15 ppm in frequency and centered, as close as possible, to the 5 ppm chemical shift value
Signal to noise levels A minimum of 20:1 for the maximum height of the smaller integrated band
Chemical shift reference: Preferably tetramethylsilane (0.0 ppm) at no greater than 1 % volume concentration
D8383 − 21
9.2 Theprocedureselectedbytheanalystwilldependonthe in solvent. The concentration of hydrocarbon oil in solvent
available NMR instrumentation. should be optimized for the spectrometer in use but can be as
high as the indicated 5% v/v value. Check to ensure that the
9.3 Appendix X1 and Practice E386 should be used in
final solution is homogeneous and free of undissolved par-
conjunction with the NMR spectrometer manufacturer’s in-
ticles.
structionsinordertoensureoptimumperformanceoftheNMR
9.6.3 UsingtheinstrumentalconditionsindicatedinTable1,
instrument in the application of these procedures.
acquireandplotthepulseFT HNMRspectrum.Assigntothe
9.4 If tetramethylsilane is used as an internal chemical shift
internal standard tetramethylsilane absorption a chemical shift
standard,preparea1%v/vTMSinsolventsolutionbyadding
value of 0.0ppm.
tetramethylsilane to chloroform-d solvent. 1
9.6.4 Fig. 1 shows an acceptable pulse FT H NMR spec-
9.5 If it is inconvenient to prepare the test solution directly trum and integration of a lubricating oil sample dissolved in
in the NMR sample tube as suggested in the followi
...