Related Experiment Video
Updated: Oct 17, 2026

Atomic Scale Structural Studies of Macromolecular Assemblies by Solid-state Nuclear Magnetic Resonance Spectroscopy
Published on: September 17, 2017
The effect of sample freezing on proton magic-angle spinning NMR spectra of biological tissue
D A Middleton1, D P Bradley, S C Connor
1Department of Analytical Sciences, SmithKline Beecham Pharmaceuticals, Herts, UK.
Abstract:
Magic-angle spinning (MAS) has recently been shown to enhance spectral resolution in NMR examinations of intact biological tissue ex vivo. This work demonstrates that freezing certain tissue samples before examination by 1H MAS NMR can have a marked effect on their spectra. Spectra of rat kidney after freezing in liquid nitrogen, compared with spectra before freezing, showed a significant increase in signal intensities from alanine (>100%), glutamine (>40%), and glycine (>100%), and a decrease in signals assigned to lipids and other macromolecules. Some resonances--such as from leucine, valine, isoleucine, and aspartate--only became visible after freezing the tissue. These observations suggest that low temperature storage of tissue necropsies or biopsies might affect the results of a MAS NMR analysis, possibly resulting in the misinterpretation of metabolite changes to pathogen or disease effects.
More Related Videos
Related Concept Videos
Proton (¹H) NMR: Chemical Shift
Absorption signals of all the protium nuclei in a...
NMR Spectrometers: Resolution and Error Correction
NMR Spectroscopy: Spin–Spin Coupling
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
¹³C NMR: ¹H–¹³C Decoupling
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...

