Continuing electron paramagnetic resonance (EPR) innovation with rapid scan EPR
Analogous to nuclear magnetic resonance spectroscopy, EPR measures electron spins, rather than those of atomic nuclei. Its investigative power has always offered unique insight, but it seems that only now is the technique coming into its own.
ELECTRON PARAMAGNETIC resonance (EPR), also known as electron spin resonance (ESR), was originally developed as a means of measuring electron spin relaxation times but has become a widely applicable tool with numerous applications within both bioscience and the pharmaceutical industry. It is used to monitor product stability, impurity profiles, degradation, flavour stability and shelf life for quality and process control. Biomedical EPR applications include the detection of free radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), to observe and evaluate oxidative stress and cell damage. Furthermore, structural insights – ranging from chemical structure to intermolecular interactions – can be obtained from both continuous wave (CW) and pulsed EPR techniques.
The evolution of EPR
Yevgeny Zavoisky first discovered EPR in 1944 in Kazan, Russia. Although EPR signals were likely observed before this time, the results were not thought to be reproducible. Zavoisky’s observations led to the development of the first EPR spectrometers, which initially used MHz frequency ranges.