What Is Nuclear Magnetic Resonance NMR?
Nuclear Magnetic Resonance (NMR) spectroscopy is an analytical technique that determines the molecular structure, composition, and purity of a substance by probing the magnetic behavior of its atomic nuclei. Certain nuclei – most importantly ¹H (proton) and ¹³C, but also ¹⁹F, ³¹P, and others – behave like tiny magnets because they possess a property called spin. When placed in a strong magnetic field and irradiated with radiofrequency energy, these nuclei absorb and re-emit energy at frequencies that depend on their precise chemical environment.
By measuring those frequencies, NMR reveals how atoms are connected, what functional groups are present, and how the molecule is arranged in space. Because the signal from each nucleus shifts depending on the neighboring atoms and electrons (the “chemical shift”), a single spectrum carries a detailed map of the molecular structure. This makes NMR one of the most powerful tools available for identifying unknown compounds and confirming the structure of known ones.
NMR was first observed in 1945–46 by the groups of Felix Bloch at Stanford and Edward Purcell at Harvard, work for which the two shared the 1952 Nobel Prize in Physics. Since then it has become a routine, non-destructive method across chemistry, pharmaceuticals, polymers, and materials science, valued for the depth of structural detail it provides without consuming or altering the sample.
Applications and Benefits of Nuclear Magnetic Resonance NMR Testing
Scope
NMR testing covers the structural identification, compositional analysis, and purity assessment of organic and many inorganic substances through the measurement of nuclear magnetic resonance signals. The nucleus observed, the field strength, and the experiment type are selected to suit the analytical question.
Key aspects of the technique include:
- Common nuclei observed – ¹H (proton) and ¹³C are the most widely used; ¹⁹F, ³¹P, ¹⁵N, and others are observed for specific applications
- Chemical shift – the resonance frequency of each nucleus shifts with its local electronic environment, revealing functional groups and connectivity
- One-dimensional experiments – ¹H and ¹³C spectra giving the fundamental structural information
- Two-dimensional and advanced experiments – correlation experiments (e.g., COSY, HSQC, HMBC) that map how nuclei are connected to each other, used to elucidate complex or unknown structures
- Sample form – most commonly solution-state, with the sample dissolved in a deuterated solvent in a thin glass NMR tube; solid-state NMR is available for insoluble materials
- Information obtained – molecular structure, functional groups, isomer and conformational information, relative purity, and the composition of mixtures
Applications
- Structure elucidation – determining the structure of unknown compounds and confirming the structure of synthesized molecules, a core use in chemistry and pharmaceutical development
- Polymer characterization – determining polymer composition, tacticity, end groups, copolymer ratios, and branching
- Chemical identification and verification – confirming the identity and purity of chemicals, reagents, and raw materials
- Mixture analysis – identifying and quantifying components in mixtures by matching signals against known spectra
- Metabolomics and natural products – characterizing complex biological and natural-product samples
- Quality control – confirming batch-to-batch consistency of composition and structure for chemical and polymer products
Benefits
- Provides detailed structural information from a single measurement – NMR reveals connectivity, functional groups, and molecular arrangement at a level of detail few other single techniques can match
- Non-destructive – the sample is not consumed or altered, so it can be recovered and used for further testing after analysis
- Quantitative – signal intensity is proportional to the number of nuclei, so NMR can quantify components and assess relative purity directly, without compound-specific calibration in many cases
- Works on known and unknown compounds – NMR both confirms expected structures and helps identify unknowns, including by matching against spectral libraries
- Versatile across sample types – solution- and solid-state methods, and the choice of observed nucleus, let the technique address a wide range of organic, polymeric, and inorganic materials
Our Testing Procedure
Prepare the Sample
Dissolve the sample in a deuterated solvent and transfer it to an NMR tube.
1Set Up the Instrument
Insert the sample, lock and shim the spectrometer, and select the required experiment.
2Acquire the Data
Apply radiofrequency pulses and collect the NMR signal over multiple scans.
3Process and Interpret
Convert the data into a spectrum, analyse the peaks, and report the structure, composition, or purity.
4Test parameters and requirements
| Parameter | Details |
|---|---|
| Common Nuclei | ¹H, ¹³C (also ¹⁹F, ³¹P, ¹⁵N, others) |
| Experiment Types | 1D (¹H, ¹³C); 2D correlation (COSY, HSQC, HMBC, etc.) |
| Sample State | Solution-state (deuterated solvent) and solid-state |
| Information Obtained | Molecular structure, functional groups, composition, relative purity |
| Sample Holder | Glass NMR tube (solution); rotor (solid-state) |
| Key Parameters | Chemical shift, multiplicity/coupling, integration |
| Nature | Non-destructive; quantitative |
- NMR spectrometer with superconducting magnet
- Radiofrequency transmitter and pulse-generation system
- RF receiver and detector for signal acquisition
- Field lock and shim system for field homogeneity
- Probe(s) for the relevant nuclei (and solid-state probe where required)
- NMR sample tubes and deuterated solvents
- Data acquisition and spectral processing software
Equipment and Instrumentation Used for Testing
What You Receive: Test Report, Data, and Certification
- NMR analysis report – annotated spectra with the structural, compositional, or purity interpretation, and the experiment conditions documented
- Assigned spectra – ¹H and/or ¹³C (and other nuclei as run) spectra with peak assignments
- Structure determination – proposed or confirmed molecular structure based on the chemical shifts, coupling, integration, and any 2D correlations
- Composition/purity data – component identification and relative quantitation for mixtures, or purity assessment, where applicable
- 2D correlation data (where run) – correlation spectra supporting the structural assignment for complex or unknown samples
- Sample records – sample description, solvent used, nucleus/experiments run, and instrument field strength
Nuclear Magnetic Resonance NMR FAQs
The sample is placed in a strong magnetic field and exposed to radiofrequency energy. Atomic nuclei absorb and release this energy, producing signals that reveal information about molecular structure and chemical bonding.
Proton NMR, or ¹H NMR, and carbon-13 NMR, or ¹³C NMR, are the most common methods. Other nuclei such as fluorine-19, phosphorus-31 and silicon-29 may also be evaluated.
An NMR spectrum shows signal position, intensity, splitting patterns and coupling between neighbouring nuclei. These features help identify functional groups, molecular connectivity, purity and chemical structure.
Chemical shift describes the position of an NMR signal relative to a reference compound. It reflects the electronic environment surrounding a nucleus and helps identify different chemical groups within a molecule.
Solution-state NMR analyses samples dissolved in a suitable solvent and usually produces high-resolution spectra. Solid-state NMR is used for insoluble or solid materials such as polymers, ceramics and catalysts.
Nuclear Magnetic Resonance (NMR) testing places a sample in a strong magnetic field and applies radiofrequency pulses to excite certain atomic nuclei. The signals produced are analyzed to identify molecular structure, chemical composition, and the properties of the material.
NMR stands for Nuclear Magnetic Resonance. It works by detecting how atomic nuclei respond to radiofrequency energy in a magnetic field, producing signals that reveal information about a molecule’s structure and chemical environment.
NMR testing services analyze submitted samples using an NMR spectrometer. The resulting spectra are interpreted to identify compounds, determine molecular structure, assess purity, or quantify components, depending on the sample and testing requirements.
Why Choose Infinita Lab for Nuclear Magnetic Resonance NMR Testing
When your Nuclear Magnetic Resonance NMR results have to hold up - for compliance, a customer audit, or an engineering decision - accuracy and an unbiased third-party report matter more than price. Infinita Lab routes your nuclear magnetic resonance NMR testing to ISO/IEC 17025-accredited U.S. partner labs with hands-on method experience, so you get defensible data, transparent reporting, and turnaround times built around your project deadline - not ours.
Looking for an Accredited Partner for Nuclear Magnetic Resonance NMR Testing?
Send query us at hello@infinitalab.com or call us at (888) 878-3090 to learn more about our services and how we can support you.
