Relaxometry vs. Spectroscopy. What’s the difference?

Both relaxometry and spectroscopy are valued NMR tools for chemical analysis. Both techniques are useful in revealing information on chemical samples.  Spectrometers have extremely homogeneous magnetic fields and can provide structural information about composition and connectivity about a molecule whereas relaxometers are less homogenous and provide time-domain data that give information about the bulk properties of a sample such as viscosity and solid fat content.

Both of these techniques are based on the observation of the interaction of radiofrequency electromagnetic radiation with an atomic nuclei’s local magnetic field (often referred to as spin). This causes an excitement in the molecule that can provide useful information, followed by a relaxation of the spins back to their equilibrium position.  

What makes NMR relaxometry different from NMR spectroscopy?

While both techniques are based upon the same principle, the speed at which the spins return to equilibrium can provide very useful information.  Relaxometers typically run a T2 CPMG based experiment. Relaxometry is used for a wide variety of things in industry analyses including spin coating, solid fat content, moisture or oil content.

NMR spectroscopy, on the other hand, gives chemically-specific information about each part of a chemical structure. This is crucial for chemists who play an integral role in the multi-billion dollar drug discovery industry.  While lesser used, it can also be beneficial in specifying samples and can therefore provide more information.  For example, relaxometry can determine the oil content of a flax seed whereas spectroscopy can provide information of the types of oils - saturated vs omega-3, for example.  

Using both NMR spectrometers and NMR relaxometers, chemists can determine a greater amount of information about the chemical structures of specific samples. 

As high-field NMR spectrometers aren’t always easy to access, benchtop NMRs can provide you the accessibility, affordability and automatability required to get the most information.  However, high-field NMR spectrometers aren't always easy to access.  Benchtop spectrometers are compact in size, robust, and easy-to-use. What's more, they're also suitable for the process environment.

Interested in adding NMR benchtop spectrometers to your lab equipment? We've got you covered. Nanalysis offers an array of benchtop spectrometers with NMR interpretation software to meet your needs. For more information on our products, contact Nanalysis today.