Spin trapping

Spin trapping is an analytical technique employed in chemistry[1] and biology[2] for the detection and identification of short-lived free radicals through the use of electron paramagnetic resonance (EPR) spectroscopy.

The spin adduct usually yields a distinctive EPR spectrum characteristic of a particular free radical that is trapped.

The identity of the radical can be inferred based on the EPR spectral profile of their respective spin adducts such as the g value, but most importantly, the hyperfine-coupling constants of relevant nuclei.

It is worth noting that the radical adduct (or products such as the hydroxylamine) can often be stable enough to allow non-EPR detection techniques.

A major advance has been the development of anti-DMPO antibodies by Mason's group, allowing study of spin trapping reactions by a simple immuno-based techniques.

An EPR spectrometer used for spin-trapping technique.
Spin trapping with phenyl N -t-butylnitrone (PBN); a commonly used spin trap.
Spin trapping with 5,5-dimethyl-1-pyrroline- N -oxide (DMPO); another common spin trap.