ASTM E2977-15(2023)
(Practice)Standard Practice for Measuring and Reporting Performance of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR) Spectrometers for Liquid Samples
Standard Practice for Measuring and Reporting Performance of Fourier-Transform Nuclear Magnetic Resonance (FT-NMR) Spectrometers for Liquid Samples
SIGNIFICANCE AND USE
4.1 This practice permits an analyst to compare the performance of an NMR spectrometer for a particular test on any given day with the instrument's prior performance for that test. The practice can also provide sufficient quantitative performance information for problem diagnosis and solving. If complete information about how a test is carried out is supplied and sufficient replicates are collected to substantiate statistical relevance, the tests in this practice can be used to establish the setting and meeting of relevant performance specifications. This practice is not necessarily meant for the comparison of different instruments with each other, even if the instruments are of the same type and model. This practice is not meant for the comparison of the performance of different instruments operated under conditions differing from those specified for a particular test.
SCOPE
1.1 This practice covers procedures for measuring and reporting the performance of Fourier-transform nuclear magnetic resonance spectrometers (FT-NMRs) using liquid samples.
1.2 This practice is not directly applicable to FT-NMR spectrometers outfitted to measure gaseous, anisotropically structured liquid, semi-solid, or solid samples; those set up to work with flowing sample streams; or those used to make hyperpolarization measurements.
1.3 This practice was expressly developed for FT-NMR spectrometers operating with proton resonance frequencies between 200 MHz and 1200 MHz.
1.4 This practice is not directly applicable to continuous wave (scanning) NMR spectrometers.
1.5 This practice is not directly applicable to instruments using single-sideband detection.
1.6 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
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: E2977 − 15 (Reapproved 2023)
Standard Practice for
Measuring and Reporting Performance of Fourier-Transform
Nuclear Magnetic Resonance (FT-NMR) Spectrometers for
Liquid Samples
This standard is issued under the fixed designation E2977; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers procedures for measuring and
E131 Terminology Relating to Molecular Spectroscopy
reporting the performance of Fourier-transform nuclear mag-
E386 Practice for Data Presentation Relating to High-
netic resonance spectrometers (FT-NMRs) using liquid
Resolution Nuclear Magnetic Resonance (NMR) Spec-
samples.
troscopy (Withdrawn 2015)
1.2 This practice is not directly applicable to FT-NMR
2.2 ISO Standard:
spectrometers outfitted to measure gaseous, anisotropically
ISO Guide 31 Reference Materials—Contents of Certificates
structured liquid, semi-solid, or solid samples; those set up to
and Labels
work with flowing sample streams; or those used to make
hyperpolarization measurements.
3. Terminology
1.3 This practice was expressly developed for FT-NMR
3.1 Definitions—For definitions of terms used in this
spectrometers operating with proton resonance frequencies practice, refer to Terminology E131, Practice E386, and Refs
between 200 MHz and 1200 MHz.
(1-4). Chemical shifts are usually given in the dimensionless
quantity, δ, commonly expressed in parts per million. For a
1.4 This practice is not directly applicable to continuous
given nucleus, the chemical shift scale is relative and is
wave (scanning) NMR spectrometers.
commonly pegged to the resonance of an agreed upon refer-
1.5 This practice is not directly applicable to instruments
ence material as described by Eq 1.
using single-sideband detection.
δ 5 ~ν 2 ν ! ÷ ν (1)
sample sample reference reference
1.6 Units—The values stated in SI units are to be regarded
3.1.1 Frequencies are given in Hertz. Because the numerator
as the standard. No other units of measurement are included in
is very small compared with the denominator, it is usually
this standard.
convenient to express δ in parts per million.
1.7 This standard does not purport to address all of the
3.1.2 As the location of a resonance is determined in part by
safety concerns, if any, associated with its use. It is the
the ratio of the magnetic field to the radio frequency at which
responsibility of the user of this standard to establish appro-
it is observed, chemical shifts and spectral regions are often
priate safety, health, and environmental practices and deter- designated as lower frequency (increased shielding) or higher
mine the applicability of regulatory limitations prior to use.
frequency (decreased shielding) relative to a reference point.
Defined in this manner, chemical shifts are independent of
1.8 This international standard was developed in accor-
dance with internationally recognized principles on standard- either the magnetic field or the radio frequency used. Coupling
constants, which are independent of the magnetic field or radio
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- frequency used, are expressed in Hertz.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
1 3
This practice is under the jurisdiction of ASTM Committee E13 on Molecular The last approved version of this historical standard is referenced on www.ast-
Spectroscopy and Separation Science and is the direct responsibility of Subcom- m.org.
mittee E13.15 on Analytical Data. Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
Current edition approved Jan. 1, 2023. Published February 2023. Originally 4th Floor, New York, NY 10036, http://www.ansi.org.
approved in 2014. Last previous edition approved in 2015 as E2977–15. DOI: The boldface numbers in parentheses refer to the list of references at the end of
10.1520/E2977-15R23. this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2977 − 15 (2023)
3.1.3 nuclear magnetic resonance (NMR) tube camber, 5.4 Analytes, Solvents, and Chemical Shift Standards—
n—maximum total deflection of any part of the outer wall of Analyte concentration is defined as a volume percentage (v/v)
the tube held at the ends and rotated 360°; a measure of the at 25 °C, that is, the volume of the analyte divided by the total
bow in the tube. volume of the solution.
5.4.1 Unless otherwise specified, the chemical purity of
3.1.4 NMR tube concentricity, n—maximum variation in
each component for standard samples used to test sensitivity
wall thickness of the tube; a measure of how centered the tube
shall be ≥99.5 weight % and the purity of each component for
inside diameter is relative to the tube outer diameter.
all other standard samples shall be ≥99 weight %. The
resonances of impurities observed in the spectrum of the
4. Significance and Use
standard sample should not interfere with the resonances of
4.1 This practice permits an analyst to compare the perfor-
interest in the standard sample. This usually means that the
mance of an NMR spectrometer for a particular test on any
impurity peaks shall not appear within the region of the
given day with the instrument’s prior performance for that test.
satellite peaks, particularly for resolution standard samples.
The practice can also provide sufficient quantitative perfor-
However, samples with higher water content may still be
mance information for problem diagnosis and solving. If
usable so long as the water signal does not interfere with the
complete information about how a test is carried out is supplied
spectral test. Water content may be determined by Karl Fischer
and sufficient replicates are collected to substantiate statistical 1
titration or by H NMR spectroscopy (protic water only). The
relevance, the tests in this practice can be used to establish the
purity of the analyte(s) shall be stated.
setting and meeting of relevant performance specifications.
5.4.2 Except as noted, the sample solvent should be deuter-
This practice is not necessarily meant for the comparison of
ated to provide a field/frequency lock for the spectrometer, of
different instruments with each other, even if the instruments
the highest purity commonly obtainable, and have an atom-
are of the same type and model. This practice is not meant for
percent deuteration of at least 99 %. The solvent’s purity and
the comparison of the performance of different instruments
level of deuteration shall be stated.
operated under conditions differing from those specified for a
5.4.3 When used, chemical shift standards should be of the
particular test.
highest purity commonly available and added to the sample to
achieve a concentration approximately one tenth that of the
5. Test Samples
analyte. The purity and concentration of the chemical shift
standard shall be stated.
5.1 In general, the test samples called for in this practice are
commercially available materials made explicitly for the test-
5.5 Sample Preparation—Either a m/m method or a v/v
ing of NMR spectrometer performance. The particular samples
method may be used for sample preparation; however, care
chosen are those that have been widely accepted by the NMR
shall be taken to assure better than 1 % accuracy in the
community of users and vendors for these purposes. However,
measurements. If a v/v method is used, the densities used for
in certain instances, especially with higher field instruments,
the liquid components shall be stated. Unless specified
the commonly accepted samples may exhibit characteristics
otherwise, any impurities in the final sample (including water)
that render them less than ideal for such uses.
should be less than 10 mol % of the analyte concentration. The
final analyte concentration and its uncertainty shall be stated.
5.2 Each sample shall be uniquely identifiable, and a cer-
5.5.1 The sample should be sealed under nitrogen or argon
tificate containing information about the sample shall be
taking care that the final sample is near atmospheric pressure.
available (ISO Guide 31). In addition to the information
5.5.2 Each sample tube shall bear a label stating its content
required elsewhere in this practice, the certificate shall list the
and reference identifier.
manufacturer of the sample, the date of manufacture, the name
of the sample, and a reference number (for example, sample 5.5.3 For long-term storage, samples should be maintained
in the dark to prevent photolysis. Except as noted, samples may
serial or lot number) (see Fig. 1).
be stored at room temperature. For long-term storage, samples
5.3 Sample Tubes—Although sample tubes with sizes rang-
containing chloroform should be kept between −25 °C and
ing from about 1 mm to 25 mm outside diameter (OD) are used
8 °C unless the sample is known to have been deoxygenated.
in modern NMR spectrometers, the 5 mm OD tube remains the
most common size. To avoid detailing test procedures for all
6. Preliminary Experimental Procedures
possible tube sizes, this practice specifies tests for use with
5 mm OD sample tubes. Users requiring sample tubes of 6.1 To achieve consistent results, the following shall be
differing size should scale the quantities, dimensions, and completed before the performance measurement:
volumes given here to the requirements of their spectrometers 6.1.1 The sample temperature should be stabilized at ap-
taking into account any specific recommendations of the proximately 25 °C, controlled during the measurement (8.16),
instrument’s manufacturer. and specified in the report.
6.1.2 The magnetic field homogeneity shall be adjusted to
5.3.1 The inside diameter of the sample container shall be
stated along with tolerances from the manufacturer. the best achievable on the sample to be used (8.9 – 8.12).
5.3.2 The quality of the tube in terms of its concentricity and 6.1.3 The observe radio frequency (rf) circuitry shall be
camber shall be stated. The concentricity and camber of the well-tuned and matched to the sample to be used. If decoupling
tube should be smaller than 0.025 mm and 0.013 mm, is used, the decoupling rf circuitry shall be tuned and matched
respectively. to the sample to be used.
E2977 − 15 (2023)
FIG. 1 Example of a Certificate of Analysis for an NMR Test Sample
6.1.4 The 90° pulse for the probe to be used should be T values is insufficient. Unless experimental conditions such
measured and reported. If decoupling is used, parameters, such as temperature or field strength are changed, the T need only
as peak power in Hertz, mean power level in Hertz, and the be determined once for a sealed sample.
decoupling modulation pattern shall be measured and reported. 6.1.6 For sensitivity tests in which the signal-to-noise ratio
The decoupling power is defined in Hertz as one divided by the (S/N) is insufficient, signal averaging may be used. If multiple
duration of the decoupling channel 360° pulse in seconds at the transients are collected, the resulting sensitivity value shall be
power level being used for decoupling. adjusted as described in 7.2.
6.1.5 The T relaxation time of the specific sample reso- 6.1.7 In cases in which the natural abundance of the
nance of interest should be measured on each sample to assure measured isotope is low, it may be necessary to correct the S/N
that the equilibration period is adequate. As T relaxation times for the actual abundance of the measured isotope in the sample
13 15
are dependent on the specific resonance observed, sample itself. Examples of this are S/N determinations for C, N,
concentration, sample temperature, magnetic field strength, and Si.
and the concentration of certain impurities (most notably 6.1.8 For both sensitivity and resolution tests, decoupling
dissolved oxygen), basing the equilibration period on literature should not be used unless specified.
E2977 − 15 (2023)
7. Reporting Results sample shall be less than 1 mol % of the ethylbenzene
concentration. The peak height of the signal from dissolved
7.1 General Tests—Results may be reported from determi-
water in the sample shall be smaller than that of the methyl
nations made by single procedures.
triplet. For very high-sensitivity systems, a more dilute sample
7.2 Signal Averaging—If signal averaging is used, the
may be used. Sensitivity shall then be converted to and clearly
measured sensitivity value shall be adjusted by dividing by the
reported as “equivalent to 0.1 % (v/v) ethylbenzene at 25 °C.”
square root of the number of transients.
The final concentration and its uncertainty shall be specified.
7.3 Tests for Establishing and Meeting Specifications—
8.1.2 Data Acquisition—The following data acquisition pa-
Specification-level test results shall be reported as the average rameters shall be used:
along with the standard deviation of the results from ten
8.1.2.1 Spectral Region—The larger of 30-ppm or 11-kHz
replications of the specified test made with no intervening
(for proton frequencies below 400 MHz) width centered on the
adjustments. For specification results, actual analyte concen-
methylene resonance of ethylbenzene.
trations and their uncertainties and tube dimensions
8.1.2.2 Equilibration Delay—At least five times the T
(specifically, either the internal diameter or the external diam-
relaxation time of the ethylbenzene methylene resonance
eter and wall thickness) shall be reported.
reduced by the acquisition time.
8.1.2.3 Pulse Flip Angle—90°.
8. Specific Test Procedures
8.1.2.4 Data Acquisition Time—4 s to 8 s.
8.1 H Sensitivity—This practice describes the determina-
8.1.2.5 Number of Transients—One.
tion of the proton sensitivity of the NMR system.
8.1.2.6 Receiver Gain—Optimized to take advantage of the
8.1.1 Sample—The sample is 0.1 % (v ⁄v) ethylbenzene in
full dynamic range of the receiver.
deuterochloroform (chloroform-d) containing 0.003 % (v/v) to
8.1.2.7 Spin
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