NMR Analysis | EUROLAB

What Is NMR Analysis?

Nuclear magnetic resonance spectroscopy is based on atomic nuclei within a strong magnetic field absorbing radiofrequency energy. The electron density around each nucleus shifts the absorption frequency; these shifts allow reading of the molecule's skeleton.

Purpose of NMR Analysis

The purpose is to directly elucidate a molecule's structure. Mass spectrometry gives the molecular mass; NMR shows how atoms are bonded to one another. A new compound's structure is therefore usually confirmed with NMR.

Which Products Is NMR Analysis Applied To?

Pharmaceutical active ingredients and synthesis intermediates
Polymer structure and copolymer composition
Natural products and plant extracts
Authenticity and adulteration examinations in food
Petrochemical products

In Which Sectors Is NMR Analysis Used?

ChemistryPharmaceuticalsFoodCosmeticsEnvironmentBiotechnologyPetrokimya

Standards Related to NMR Analysis

European Pharmacopoeia 2.2.33 (nuclear magnetic resonance spectrometry)
ISO 24583-type qNMR application guidelines

NMR Analysis Conditions

Sunflower seed: Usually ¹H and ¹³C; also nuclei like ¹⁹F, ³¹P
Solvent: Deuterated solvent required; selected according to the sample
Experiment type: Tek boyutlu veya iki boyutlu (COSY, HSQC, HMBC) korelasyon deneyleri
Quantitative measurement: qNMR requires relaxation time and internal standard

Equipment for NMR Analysis

Superconducting-magnet NMR spectrometer
Multinuclear probe
Automatic sample changer
Cryogen supply infrastructure
Spectrum processing software

Sample Requirements for NMR Analysis

The sample must dissolve in a deuterated solvent
Generally a few milligrams to tens of milligrams of sample is required
Paramagnetic impurities (iron, manganese) distort the spectrum
The sample must be filtered to remove solid particles
The analysis is non-destructive; the sample can be recovered from the solution

Duration of NMR Analysis

A routine ¹H spectrum takes minutes. ¹³C and two-dimensional experiments can extend to hours; quantitative measurements require longer wait times.

NMR Analysis Procedure

1The sample is dissolved in a deuterated solvent and transferred to an NMR tube.
2Magnetic field homogeneity is adjusted (shimming).
3A suitable pulse programme is selected and the spectrum is collected.
4The spectrum is processed by Fourier transform, and phase and baseline are corrected.
5Chemical shifts, splitting patterns and integrals are interpreted.
6Connectivities are confirmed with two-dimensional experiments if required.

NMR Analysis Acceptance Criteria

Acceptability of structure confirmation is assessed by comparison with a reference spectrum or monograph; the purity limit comes from the registration dossier or the pharmacopoeia.

Evaluation of Results

Structural interpretation relies on the joint assessment of chemical shift, integral and coupling constants. If quantitative NMR is performed, relaxation times must have been accounted for the result to be valid; otherwise integrals do not reflect the true ratio.

NMR Analysis Report

Sample description, receipt date and laboratory number
Method applied and reference standard, if any
Instrument and measurement conditions
Sample preparation steps
Measurement results and units
Measurement uncertainty (if requested)
A statement that the results relate only to the sample submitted for testing

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

European Pharmacopoeia and USP monographs
ICH Q6A (specifications)
Reference databases used in food authenticity audits

Pages Where This Method Is Used

Analytical Methods — What Does This Group of Methods Do?

The section below describes the field that the NMR Analysis test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

Analytical method pages are pages about a MEASUREMENT TECHNIQUE rather than about a test. The difference matters: "salt spray testing" is a test and answers one question; "ICP-MS" is a technique and is used in dozens of different tests. Sometimes the user is looking not for the test but for the technique — because the method name is what appears in their specification.

This distinction becomes decisive in choosing a laboratory. When a customer asks for "heavy metal analysis", the real question is by which technique it will be done: XRF is fast and non-destructive but does not distinguish compounds; AAS is economical for a single element; ICP-OES screens multiple elements; ICP-MS sees trace levels. The same sample gives results with different detection limits and different uncertainties across the four techniques.

Method selection is made against three criteria. DETECTION LIMIT: is the concentration sought within the range the method can see? MATRIX COMPATIBILITY: is the sample matrix (plastic, food, soil, metal) one the method can handle, and is pre-treatment required? SPECIFICATION LINK: does the product standard or legislation mandate a particular method? The third often overrides the first two — the specification binds the method.

Method pages build a CHAIN. A technique is linked to the test pages where it is used, to the standards those tests rest on, to the legislation those standards are tied to and ultimately to market access regimes. The example chain in the source document works like this: XRF → metal analysis → RoHS compliance → heavy metal restriction → coating pages. Whichever link the user enters from, they reach the others.

Sample preparation is the invisible half of the result in this family and is a greater source of error than the technique itself. The digestion method, degree of grinding, extraction solvent and dilution ratio change the result markedly. The same sample on the same instrument gives a different result with different preparation; the definition of the method therefore covers preparation too.

Calibration and verification are the third determining component. An instrument is calibrated with certified reference material, the calibration curve is verified periodically and a control sample is run in each batch. Without these steps, a number produced is not traceable even if the instrument is working correctly.

Method groups in this field

Elemental analysis
ICP-OES, ICP-MS, AAS and XRF. They differ in detection limit, matrix tolerance and multi-element capacity.
Chromatography
GC, GC-MS, HPLC, LC-MS/MS and ion chromatography. It separates a mixture into its components and measures each separately.
Spectroscopy
FTIR, Raman, UV-Vis and optical emission. For material identity, functional group identification and alloy composition.
Thermal analysis
DSC, TGA, DMA and dilatometry. Transition temperatures, composition, decomposition and dimensional behaviour.
Microscopy and imaging
Optical microscopy, SEM-EDS, radiography and tomography. Structure, defects and elemental distribution.
Classical (wet) chemistry
Titration, gravimetry and colorimetry. Used as a reference method and in confirming instrumental results.

Commonly confused in this field

XRF is a screening tool; it sees elements and does not distinguish compounds. A decision on a restricted compound requires confirmation by wet chemistry.
The phrase "not detected" is not proof of absence; it is read together with the detection limit of the method.
The specification binds the method. A technically better method is not accepted if the specification calls for another.
Sample preparation is part of the result; a report that does not state the preparation is not reproducible.
Results obtained by different techniques cannot be compared directly; their detection limits and uncertainties differ.
A method page is not a test page; which method applies to which test comes from the product standard.

Which decisions these results support

Matching the method written in the specification to the laboratory's scope
Method selection according to detection limit and matrix compatibility
Confirming an instrumental result with a reference method
Eliminating deviations arising from sample preparation

Related Tests

Frequently Asked Questions About NMR Analysis

Can purity be measured with NMR?

Yes. Quantitative NMR (qNMR), with a suitable internal standard and relaxation conditions, can give absolute purity; this method is also used in reference material certification.

Can the sample be recovered?

The method is non-destructive. The sample can largely be recovered by evaporating the solvent, though deuterated solvent residue may remain.